REnescience - PSO report 7335

Transcription

1 REPORT REnescience - PSO report 7335 Prepared Nanna Dreyer Nørholm (NADNO), 26 September 2011 Checked Inger Marie Nielsen (INGNI), 22 December 2011 Accepted Georg Ørnskov Rønsch (GEORR), 19 January 2012 Approved Nanna Dreyer Nørholm (NADNO), 23 January 2012 Ver. no A Case no

2 Contents 1. Introduction and project background Reading instructions Summary Project execution Scientific and technical findings WP1 Optimisation of liquefaction of waste in lab scale Process optimisation in Lab scale Results Enzyme optimisation WP5 Design of demonstration plant for waste liquefaction Lab-scale to full-scale Data sampling and reliably of the process Experiments in heating-, cooling- and enzyme- batch reactor WP8 Procurement and construction of a demonstration plant for waste liquefaction WP12 Demonstration and optimisation of waste liquefaction Pilot plant Experiments in continuous process WP6 Continuous liquefaction of straw WP4.1 Supercritical gasification test of liquefied straw and waste, lab. scale Objective Background to the CatLiq technology Prestudy Pilot study Conclusion WP4.2 Scanning of biogas potential from the bioliquid Test II Conclusion WP4.3 Full scale tests in Fredericia Rensningsanlæg (Fredericia Spildevand A/S) Purpose of fermentation trial at Fredericia Spildevand A/S Full-scale test Conclusion September 2011

3 5.9 WP16 Products and system evaluation Handling the solid fraction washing and sorting Heating waste with water instead of using steam Using the bioliquid for incineration or gasification Waste inputs and value outputs Feedstock Outputs from the REnescience process Bioliquid RDF (Refuse Derived Fuel)/SRF (Specified recovery fuel) Solid fuel Recyclables Use of output from the REnescience process WP7 Evaluation of the liquefaction concept, environmental assessment, feasibility etc Life cycle assessment Initial feasibility WP13 Environmental evaluation and feasibility study of the concepts Calculation model for the REnescience technology Life cycle assessment Feasibility WP9 Testing of the liquefied straw on existing entrained flow gasifiers WP10 Design and construction of a gasoline demonstration plant WP11 Demonstration of a flexible gasoline production based on entrained flow gasifier WP15 Gasification and poly-generation WP15.1 Poly-generation. Identification of the optimum layout of an integrated gasoline/power plant WP15.2 Re-fuel with biomass by a gasification process WP14 Project management Financial Conclusion References Enclosures List of publications September 2011

4 1. Introduction and project background REnescience refers to an amalgamation of Renewables, Science and Renaissance of the energy system. The PSO REnescience project has been executed in cooperation with Amagerforbrænding, the Technical University of Denmark, the University of Copenhagen, Haldor Topsøe, Novozymes and DONG Energy. DONG Energy is initiator and with the reasonability of project management. The work has been supported by Energinet.dk. This report is submitted in accordance with the provisions of the updated Terms of Reference agreed with Energinet.dk. The technological invention is based on a municipal solid waste (MSW) separation method that uses enzymes to liquefy the organic compounds so that they can be easily separated from the inorganic waste such as plastic, metals and textiles. A schematic overview can be seen in Figure 1. Figure 1 The REnescience process Other separation techniques have been used over time and developed for the purpose of separating the unsorted waste. Most of these techniques involve mechanical treatment including severe shredding for downstream separation techniques. Mechanical separation techniques have a low separation power, losing between 30-50% of the organic and degradable material. Source sorting is another way of collecting the household waste in its respective fractions. However, this separation technique is hard to practise and expensive to run. The REnescience technique worked perfect in small scale test runs and this project with the financial support from the Danish Energy Authority funded research project called PSO REnescience aims to investigate the possibilities to make the separation process in large scale. Page 4/89

5 The project started with two main objectives, to liquefy and separate organic waste from MSW and to investigate the possibility to generate a fuel suitable for a polygenerated energy system. The aim with the latter was to investigate whether it was possible to use waste as a flexible fuel source. The organic part of the waste should be treated in such a way that it would be possible to use it in a gasification process. The products from the gasifier could then be used directly in a turbine or processed to a liquid fuel that could be stored and used in the transport sector. The system can be seen in Figure 2. Figure 2 Polygeneration system where energy can be used in the sector with the biggest need. A number of work packages (WP) including well defined goals were set up and they will be presented in this report. Though some of the experimental work has been executed in close collaboration with Amagerforbrænding, the comparisons stated with respect to economic or environmental feasibility are related to average Danish waste CHP plants, not specifically to existing or planned Amagerforbrænding conditions. Page 5/89

6 2. Reading instructions In order to make this report as easy to read as possible for those who have not been involved in the project, this is a short guide to the disposition of the report. Section 1, Introduction states the original project aim and purpose and gives a short background to the technology. During the project, some changes have been made to the original concept, which is stated in section 4, project execution. Due to the changed project description, some of the work packages have already been reported and some have been reduced, which is why the order of the work packages has been changed to make the report easier to read. The work packages and the order of these are presented in section 5. The work package WP15.1, which have been reported already, is presented as a summary and attachment in this final report. The financial and project evaluation (WP14) can thereafter be found in sections 6 and 7. The project conclusion can be found in section 8. Due to the project split, the sections about gasification and poly generation should be seen as isolated investigations and very little focus is put on these studies in the conclusion in this document. Page 6/89

7 3. Summary Enzymatic liquefaction process What initiated this project was that a promising method for separating household waste into an organic liquid fraction (bioliquid) and a solid fraction by means of enzymatic liquefaction had be identified. The method had been screened with different waste types in bench scale level and the aim of this project was to develop the enzymatic process to a continuous run process in pilot scale as well as to investigate the possibilities for the method regarding technological exploitation of the fractions and the economic feasibility for the method. Initially a number of identical waste mixes was produced to be able to test and compare the different enzyme mixtures and process parameters in both lab scale and bench scale. The tests on the waste mixes provided valuable information for designing the first pilot-scale batch reactor, which was constructed and put into operation ultimo 2008 at Amagerforbrænding. The reactor was designed to later become the first reactor of the continuous run pilot plant. Tests performed in this reactor made good basis for the design and construction of the continuous run pilot plant which was put into operation in during the COP15 in December The pilot plant which can be operated automatically and it has now been in operation on daily basis for nearly two years on MSW from the Copenhagen citizens. This has given very good experiences on mechanical and operational challenges and it has been possible to produce downstream fractions for tests in larger scale. Page 7/89

8 The plant comprises the following process steps; heating, cooling and enzymatic treatment. At the pilot plant the enzymatic treatment step is followed by a simple sieve system, but in a commercial set up the separation system shall comprise steps suitable for the later usage of the fractions. The solid fraction can potentially be used for several purposes and the focus has been on utilization for energy purposes as well as sorting out metals and inorganic parts. The heating value of the solid fraction can be compared to the heating value of industrial waste or RDF which for instance is suitable as fuel for cement kilns and power plants. To assure an optimal separation of the solid fraction and the bioliquid a washing plant was designed and later installed in another project. The bioliquid has an organic dry matter content of approximately 20% and yet still a low viscosity that enables pumping. Potentially the ways to use of the bioliquid are numerous, as indicated in the figure above. The bioliquid was investigated and tested to produce several products, such as biogas, ethanol, syngas and bio-oil. The bioliquid was immediately suitable for biogas production both in combination with manure and sewage sludge and solely. The bioliquid has a very short digestion time and thus a short conversion time of biogenic mass to methane. The biogas potential was measured in the span from 340 to 400 Nm3 CH4/ton VS and it is considered as a very appropriate feedstock for biogas production. It is possible to capture more than 90% of the biodegradable part of MSW in the bioliquid, which corresponds to more than 50% of an average The preliminary financial and environmental studies that have been made indicates that the REnescience technology can be a competitive technology, even for the Danish market with a highly energy efficient waste treatment system. Thermal gasification & Polygeneration Thermal gasification of biomass was investigated as a study with the existing power plant Skærbæk Power Station used as case study. The main fuel source was considered to be wood chips or wood pellets. It was also investigated whether the gasification process could use the dried bioliquid fraction from the REnescience process in a combination with wood or even the plastic fraction from the solid fraction. The conclusion of the investigation was that project seems technically feasible, even though some of the techniques are immature, especially the gas filtration technique. It is a viable business case, provided that existing subsidy schemes on biogas from gasifiers exists during the lifespan of the installations. The investigation of the flexible energy system - or as it is called the polygeneration concept - is based on a TIGAS (Topsøe Integrated Gasoline Synthesis) process where the synthesis gas from the gasifier is converted into either gasoline or power and heat depending on the value of the products. Due to the high fluctuations in power price the optimal product may change on an hour-tohour basis. Two different polygeneration concepts were studied; one optimised for "max gasoline" and one for "max power". These concepts were investigated regarding to the predicted forecast for the Danish Page 8/89

9 energy system. Due to the forecast of large amount of wind power in the energy system it turned out that the max gasoline concept was the most profitable. The polygeneration concept shows a promising way to provide low cost green fuel for transportation and green district heating with both high energy and exergy utilisation of the biomass. The key challenges to mature the polygeneration concept is development of high temperature dust filter and tar reformer. Page 9/89

10 4. Project execution The REnescience project has been characterised by great flexibility from both project partners and our sponsor to continuously learn from the knowledge gained in the project to adjust the direction, cut out parts that was evaluated not to be feasibly and put in other alternatives that showed up to be very interesting. In that way the project description has never stopped developing. This has of course generated some extra work in the project management and for our sponsor, but also led to a final product, meant as a technology development, which is highly relevant for today s market, and wanted by key market interests. The major change in the project was agreed on in May 2010, when the idea of pressurised gasification of bioliquid from household waste was altered to a biogasification of the bioliquid. The decision secured the feasibility and the relevance of the project but cut up the original concept in two separate technology concepts. One concept regarding the energy production from household waste, and one concept regarding the use of syngas from gasification for a flexible liquid fuel and/or power production depending on the market demand. Both projects are still very relevant but the connection between them turned out not to be viable. Liquefaction, gasification and polygeneration were therefore separated as shown in Figure 3. Figure 3 Illustration of the project split This major project change generated a new work package description and budget for most work packages and a new time schedule for the remaining part of the project. The changes in the work package descriptions and time schedule are found in the letter PSO Project REnescience Change of the Work Packages dated May A new work package was announced in this letter, Work package 16: Products and system evaluation. The main focus in this work package was to evaluate the products from the REnescience process, mainly the solid fractions. The evaluation of the solid fractions was a two-step task: First to design a washing system to produce high quality solid fractions, secondly to test these fractions for Page 10/89

11 several uses. In the change letter these two steps was weighted equally, but step one turned out to be significantly more difficult and time consuming than expected. Therefore more efforts have been put in step one than planned, and consequently less in step two of the evaluation. During the project period, status reports have been sent to Energinet.dk every half year describing the progress and the work in every work package, and the intermediate results from the work. These results were the main reason for the work package change in May Furthermore, steering group meetings have been held to coordinate the work between the work packages and between the partners of the project. Page 11/89

12 5. Scientific and technical findings This section will describe some of the scientific and technical findings that have been found. Some of the work packages will be presented in a different order with regard to their number, to make the presentation of the work as logical as possible WP 1 WP 5 WP 8 WP 12 WP 6 WP 4.1 WP 4.2 WP 4.3 WP 16 WP 7 WP 13 WP 15 WP 15.1 WP 15.2 WP 9 WP 10 WP 11 Optimisation of liquefaction of waste in lab scale Design of demonstration plant for waste liquefaction Procurement and construction of a demonstration plant for waste liquefaction Demonstration and optimisation of waste liquefaction Continuous liquefaction of straw Supercritical gasification test of liquefied straw and waste, lab. scale Scanning of biogas potential from the bioliquid Full scale tests in Fredericia Rensningsanlæg Products and system evaluation Evaluation of the liquefaction concept, environmental assessment, feasibility etc. Environmental evaluation and feasibility study of the concepts Gasification and poly-generation Poly-generation. Identification of the optimum layout of an integrated gasoline/power plant Re-fuel with biomass by a gasification process Testing of the liquefied straw on existing entrained flow gasifiers Design and construction of a gasoline demonstration plant Demonstration of a flexible gasoline production based on entrained flow gasifier Page 12/89

13 5.1 WP1 Optimisation of liquefaction of waste in lab scale The aim of this work packages was to optimise the liquefaction of waste. The work has been conducted in two parallel tracks. One of the tracks has been an overall optimisation for the liquefaction process including pretreatment, mechanical influence, enzymes, water etc. The work has to a high degree been directed by the need for data and information in relation to design and construction of the pilot plant. Some of the work is presented in section The other track has been related to enzyme optimisation. The main part of the work related to this has been carried out as a PhD project. The PhD project focussed on studying the enzymatic hydrolysis and liquefaction of waste biomass with the purpose of studying whether the liquefaction of waste biomass was uniform bioliquid generation. Highlights from the PhD thesis are presented in Process optimisation in Lab scale The aim of the lab scale test has been to simulate the process conditions in the pilot plant that was to be designed and constructed. Therefore, different process configuration and process conditions have been simulated. For the different tests there has been used MSW, designed waste and green waste (sources separated) Equipment used The core in all the initial test at lab scale has been the test reactor ELSE. ELSE was constructed before the beginning of the PSO project. The best description of ELSE is that it is a large washing machine, with an inner rotating drum (see Figure 4). The treatment capacity of ELSE is 50kg waste per batch. Figure 4 Lab scale testing reactor ELSE There are four different drums for the reactor, one with a solid drum surface and three with a perforated drum surface (5, 10 and 15 mm holes). The reactor is equipped with a heat/cooling jacket Page 13/89

14 (operating temperature 5-95 C). With this cofugration of the bench reactor, it has been possible to conduct many different types of tests and simulate different process configurations. The reactor was used to perform boiling and enzyme treatment and the separation of the waste fractions. It was important to find the optimal boiling time, enzyme treatment time and amount of water that was optimal for the treatment. At the end of the project ELSE was used for the initial test with washing of the solid fraction (see WP 16 section 5.9.1) Experiments with design waste The first experiments in ELSE was conducted with MSW. MSW is very inhomogeneous (difficult to sample) and the composition varies a lot. This resulted in a large variation from experiment to experiment. The variation between two identical experimental set-ups could be up to three times the expected effect of change in experimental parameters. It was therefore concluded that it did not make sense to keep making experiments with MSW in lab scale. It was therefore decided to substitute MSW with a designed waste fraction that could be replicated in all further lab scale experiments. The Danish Technical University, DTU, supplied a waste composition 1 that could be used to generate a design waste that reflected real MSW. The pictures in Figure 5 are from the first mix of design waste. Figure 5 Design the waste representing composition of Danish MSW When using the design waste for experiments there was found a good compliance between replicates with the same experimental settings Initial test with designed waste Over a period of nine months a total of 19 test runs were conducted in ELSE. The 19 test runs were grouped in three experimental designs, with the following design parameters: The first setup Temperature in the boiling step (55 C and 95 C) Open and closed reactor drum (5mm holes and smooth drum surface) 1 Waste composition from DTU was later published in Waste Management 29 (2009) Page 14/89

15 The second setup Water content (addition of 25, 35 and 45kg water per 45kg design waste) Types of enzymes (cellulase and mix of cellulase, alfa-amylase and pectinase) The third setup Water content (25, 45 and 65kg water per 45kg design waste) Enzyme concentration, enzymes used (mix of cellulase, alfa-amylase and pectinase) The same standard experimental procedure was followed in all the experiments. The procedure can be summarised as: Definition of the experimental setup 2 and the experimental parameters Preparation of the design waste (6-7 portions at the time) Heating ELSE to desired temperature (eg 95 C) Adding the design waste and keep boiling temperature for desired time Cool to desired temperature for enzyme treatment and ad enzymes Keep temperature and rotating of inner reactor drum for desired time After ended treatment time a bucket is placed under ELSE and the liquid fraction is drained through a valve into the bucket. The amount of bioliquid is measured and samples are taken for analysis (dry matter (DM), ph, ash content) The inner drum is emptied and the solid fraction is weighed Optional, a washing step can be added (eg repeated 2-3 times) o A defined amount of water is added and drum rotated for a given time period o The washing water is drained through a valve into a bucket under ELSE (samples are taken for analysis) o The inner drum is emptied and the solid fraction is weighed 2 REnescience has a history using Design of Experiments (DOE) when running experiments. In a typical DOE experimental setup there is seven individual test runs. A setup with seven test runs in an experimental setup gives the opportunity to run a simple two-level factorial design (2 2 ) with three centre points or a reduced three-level factorial design (2 3-1 ) with three centre points. Page 15/89

16 The setup is illustrated in the pictures below. The design waste consists of "fresh waste" from the supermarket (bread, meat and vegetables), "used" paper (newsprints, advertisements), cardboard (eg milk cartons), plastic (foil, containers), glass, metal, soil (and more). The design waste was not size reduced or pre-treated in any way. After enzymatic treatment, a bioliquid could be sieved from the inner drum and drained through a valve into the bucket under the reactor (picture to the left). The solid fraction with metals, textile, plastic and wood was left in the inner drum (picture above). Dry matter, ash content, particle size distribution and ph have been some of the standard analysis used for characterisation of the bioliquid. All the test runs in ELSE were conducted in the period where the focus was to liquefy the biomass so that it could be added to a pressurised coal gasification unit. The main focus was therefore on achieving a bioliquid with high dry matter (DM) content and a low particle size. Another focus was to extract the main part of the bio-degradable from the waste into the bioliquid. Page 16/89

17 5.1.2 Results In the following section, the results from one of the test runs will be presented. After one hour at 95 C, the main parts of the biomass turn into a grey pulp (picture above to the topleft). After enzymatic treatment in 12 hours the grey biopulp is turned into a liquid fluid (picture above at the top-right) called the bioliquid or bioliquid fraction. The bioliquid can then be separated from the solid fraction. After washing the solid fraction, the metals and the main part of the plastics are free of bioliquid (picture above at the bottom-right). A screen dump of a mass balance is shown in Figure 6 to illustrate a mass distribution in the different fractions from a typical experiment. Guide through the mass balance: The first blue box illustrates ESLE As output from ELSE after enzymatic treatment there are a bioliquid fraction (Bioliquid 1) and a solid fraction (Residual 1) Water is added to the solid fraction in ELSE and a washing step is performed After the washing step the washing water (Bioliquid 2) is separated from the solid fraction (Residual 2) Residual 2 is then pressed into a 20 tonne workshop press From the workshop press there are a solid fraction and a press bioliquid Figure 6 Typical mass balance from one test in ELSE Page 17/89

18 From the mass balance above it can be seen that a total of 14kg dry matter ends up in one of the three bioliquid fractions (approx 60% of the dry matter in the design waste). Of this dry matter approx 55% is recovered in the bioliquid 1 (primary bioliquid), approx further 40% in the bioliquid 2 after the washing step and the last approx 5% is recovered in the press bioliquid. This indicates that in order to recover the main part of the biomass, it is necessary to include a washing step in the REnescience process. The bioliquid from the press only includes a small amount of dry matter but approx 20% total amount of water in the system. The REnescience process needs addition of water. It therefore seems obvious to include a pressing step in the process and use the recovered water as process water. This could reduce the consumption of water with approx 20% (when 1kg of water is added to 1kg of MSW, which is the experience from the pilot plant) Enzyme optimisation The enzyme optimisation work was carried out as a PhD project. The Ph.D. project focussed on studying the enzymatic hydrolysis and liquefaction of waste biomass with the purpose of studying the liquefaction of waste biomass was uniform bioliquid generation. The work involved evaluation of 1) different enzymes and their liquefaction performance on modelled waste simulating Danish household waste in composition and weight, 2) evaluating the performance of best enzyme candidates on MSW with and without additional additives. Model waste was mixed from different types of organic fractions (paper, meat, vegetables etc.) and minced to an even particle size of < 5 mm. This model waste is used for enzyme screening in lab scale concerning small bottle trials on samples as small as 30 grammes in small 100ml bottles. Model waste is collected according to the statistical data from Denmark, mixed and chopped for labscale trials. The fabrication steps concerning the chopping and mixing of model substrate components is about lowering the variation between trials and trial samples. Model waste contains around 40% cellulose, 13% fat and lignin, 11% ash and other constituents in lower concentrations. Composition results show cellulolytic enzymes to be highly relevant enzyme preparations but other enzymes and preparations may be beneficial for the liquefaction of MSW. The initial work shows that only few enzyme preparations perform satisfactorily when evaluated on particle size and viscosity of liquid product. There is no effect of a starch degrading enzyme; a- amylase even when using an a-amylase performing where starch is gelatinised at a temperature of 80C. Proteases degrading protein has small effect on liquefaction of household waste but negative effect when used in interaction with other enzymes. Cellulolytic enzymes, which are a complex preparation of several enzymes working on cellulose, have the singular effect on liquefaction of household waste. The work of liquefaction is evaluated based on viscosity change (lowered viscosity) and particle size distribution. Degradable material with a particle size above 1mm after treatment evaluated using SEM microscopy shows paper particles to be main obstacles needing additional treatment in order to become fully liquefied. Enzymes found in initial work are tested on authentic MSW in the pilot scale reactor, ELSE, comprising all MSW components as unsorted waste. Starch degrading a-amylase is co-added in some trials with cellulolytic enzymes in order to look for synergistic effect that may show possible in Page 18/89

19 large scale trials. Results show that it is possible to gain 90% of degradable material such as organic constituents and paper in the liquefied product. Concurrently, results show that a-amylase has no synergistic effect when co-added with cellulolytic enzymes. Cellulolytic enzymes have the singular significant effect on the liquefaction of unsorted MSW that is similar to the lab-scale trials. Following the enzymatic hydrolysis, the liquefied product is separated from the non-degradable solid fraction by simple sieving. The nondegradable solid fraction consists of components such as glass, metal, wood and plastic. Enzymatic treatment of MSW is shown to be able to separate the biogenic fractions from the solid non-degradable fraction. The pilot scale reactor performs enzymatic treatment at up to 35% DM, showing that this process can manage high DM loadings. MSW treatment involves an enzyme process environment much different from common utilisation of enzymes such as cellulolytic enzymes. Performance of cellulolytic enzymes in concentrated wastewater is investigated. Concentrated wastewater is collected at the demo-scale pilot plant treating MSW in continuous process that concentrate dissolved substances like ions, salts and water extractive molecules. This wastewater contains calcium, sodium, potassium, chloride and others that may affect cellulolytic enzymes. EDTA was suggested as an additional component to react and bind ions in the waste, which was tested for optimised cellulase performance. The addition of EDTA shows no measurable effect on the cellulolytic enzyme performance in the MSW wastewater matrix compared to the performance in buffered MilliQ water when hydrolysing clean filter paper. It is therefore concluded that the cellulases are stable and tolerate the presence of several contaminants. Surfactants or surface-active-agents are chemicals or compounds that contain a lyophilic (solvent loving) group and a lyophobic (solvent fearing) group. Surfactants are used in many industrial processes such as washing powder and for the emulsification of chemicals in aqueous solutions. Surfactants are used in connection with: wetting, foaming, emulsification, dispersion of solids in liquids, solubilisation of solvent-insoluble material, or viscosity increase or decrease of the solution phase. Surfactants have shown positive results at enzymatic hydrolysis of agricultural waste such as wheat straw. A focus point for the enzymatic hydrolysis of thermally treated MSW is the addition of surfactants to the process. No effect of surfactant addition is found as measured by viscosity and particle size distribution. Used enzymes do not seem to be bound on surface that can be occupied by surfactants, which may increase the concentration of free and active enzyme proteins in the process. These tests include samples with very low enzyme addition compared to samples containing four and seven times the enzyme concentration. The low enzyme addition shows no positive effect of surfactant addition. Concurrently, we test two different commercial cellulolytic enzyme preparations resulting in the same results; improved performance at higher enzyme concentration and no effect of surfactant addition at any level of enzyme addition. Page 19/89

20 5.2 WP5 Design of demonstration plant for waste liquefaction The aim of designing a continuous fed plant for waste liquefaction is to verify the potentials of the REnescience technology. A continuously fed plant has the possibility to investigate waste variation over time and how this will impact the enzymes as well as the chemical composition of the treated waste. A contiguously fed plant is also one step closer to a commercial full-scale plant. With the plant mechanical investigations could be made to investigate the stress and corrosion of material in the plant. Technical solutions for transporting, feeding, separation and reactor design could be evaluated. It was important for further investigations to get a better view of the process design of the plant. Energy consumption was an important issue to investigate as well as the handling and enzymatic treatment in a continuously fed reactor. Process control is also an important aim of the pilot plant, proper water concentration, dry matter control and measuring of liquefied fraction. It is also important to investigate the ratio of separation of the organic fraction. The plan for the pilot plant was that the sections should consist of three almost identical units: one heating reactor section, one cooling reactor section and one enzymatic treatment reactor section. Figure 7 Early process and flow diagram over the process Lab-scale to full-scale One of the challenges when moving from lab-scale to full-scale for the REnescience plant was to adjust the scale of the pilot plant to the large verity in particle size in MSW. One of the targets was to design a plant as small as possible but without having to shred or pre-treat the waste before adding it to the process. By treating the material unshredded it was possible to receive results that would Page 20/89

21 reflect a full-scale plant as much as possible. The best solution was to only use MSW from areas in Copenhagen using underground waste collection systems. The inlet and outlets from these containers are reduced to 300mm which naturally reduces the size of the waste. The original plan was to design a continuous plant for 100kg/h. However, with the new requirement for the waste dimension the plant could handle a much higher capacity. The plant was therefore designed with a capacity of 600kg/h Data sampling and reliably of the process MSW is such a variable source that it was important to collect data that reflect the variation over the year and also over the day to be able to track the chemical composition of the products. It was therefore important to design a plant that could process waste over a long period of time. It was therefore designed as a fully automatic plant with few or no manual operations. Data were collected every day and sometimes every second hour. The sampling was performed manually by the operator. Another important parameter to check was the process reliability. Waste is produced every day all year round and waste containing organic waste needs to be treated directly to prevent release of methane and other gases. Reliability is therefore important both to the environment and for the storage capacity in the waste collection silo. A daily inspection routine was performed to inspect the mechanical component and a weekly report was written to document improvements or errors. The main focus during the inspection rounds has been to inspect the sealings between the feeders (and vibrating sieves) and the rotating drum reactors, pumps and bearings Experiments in heating-, cooling- and enzyme- batch reactor As it quite early in the design process became obvious that the core of the REnescience process should consist of a series for drum reactors, it was decided to first design and construct one of the reactor drums and test the design in relation to boiling, cooling and the hydrolysis process. The first reactor was named ROMLE (REnescience Organic Matter Liquefying Equipment). The setup consisted of a feeder and a vertical rotating drum reactor. The setup was temporally placed on the unloading ramp at Amagerforbrænding I/S. With this location there was easy access to MSW, and it was possible to make the initial test of the equipment. The waste was loaded into the feeder funnel by using a telescopic front lifter equipped with a tilt container. The waste was preheated in the feeder pipe just before going into the reactor. The reactor was designed to contain 1200kg MSW and experiments were conducted in both continouos and batch modes. Page 21/89

22 The test and some of the results are briefly described in the following. Table 1 shows the test performed and purpose of each individual test. Table 1 Test performed in batch reactor, Romle. Test Purpose Result Enzymatic retention time Cooling test Enzymatic treatment capacity (in batch mode) Boiling capacity in continuous mode Temperature optimisation Water content Separation test (soild/bioliquid after hydrolysis) Find the optimum treatment time of the waste generate design data for the hydrolysis reactor Test cooling method and cooling time dertermine if cooling in a drum reactor was possible Find out how much waste the reactor can handle To estimate the boiling capacity in the drum reactor. Check the ability to obtain an uniform temperature distribution in the waste Find the optimum water content, during both heat and enzymatic treatment Evaluate the optimum separation method Depending on the load and type of enzymes the retention time varied between hours 1000kg of waste could be cooled 50 C within 30 minutes 1000kg of waste could be treated in one batch. At this load it was still possible to maintain balance in the reactor 500 kg of waste could be heated to 90 C and treated for 30 minutes in continouos operation mode. The bottleneck was the capacity of the steam generator At the beginning it was difficult was document the temperature in the waste. A homemade setup was therefore developed, see text in Ratio of waste/water was tested from 1/0 to 1/2. It was found that the optimal ratio is very dependent on the waste composition Different techniques were tested and the best solution was found to be a vibrating sieve. It was not possible to obtain a sufficient separation of the solid and liquid fraction. The optimisation of the separation is an on-going process Some of the experiments listed above are in the following described in more details Mechanical test The first test that was conducted was in relation to the transporting ability in the drum (getting the waste from the inlet to the outlet). Another issue was to investigate the mixing effect in the reactor. The first test was conducted at the manufacture and was only done on dry material. The scope of the test was to investigate the mixing and transport in the reactor. The reactor was filled with a mix of newspaper, plastic foil, grain, wooden blocks, plastic bottles and pieces of metal pipes. Page 22/89

23 The test indicated that the controls of the residence time by forward and backward rotation needed to be optimised. The challenge was to keep balance in the reactor so that the flow out of the reactor could be controlled precisely. The test also indicated that there was a good mixing in each chamber in the reactor and only a small mixing between the chambers (important in relation to maintain a plug flow through the reactor). With the test successfully completed, the reactor and feeder system was transported to Amagerforbrænding I/S. At Amagerforbrænding, the same test was conducted with MSW and similar results were obtained Boiling test It was demonstrated that it was possible to heat the waste from approx 20 C to 95 C within five minutes and to hold this temperature through the whole reactor. This was documented by sending a Temperature Data Logger through the reactor. The data logger was sealed in a homemade container which protected the data logger in the hostile environment in the reactor. In order to be able to monitor the temperature in the reactor, a temperature sensor was sent through the reactor together with the waste. The large metal disc made it easier to find the temperature sensor after it had been in the large boiling reactor. It was at the same time demonstrated that the temperature measurement inline in the reactor was representative of the temperature in the waste. Figure 8 shows four temperature logs during heat treatment. Page 23/89

24 Figure 8 Temperature logs during heat treatment The yellow line indicates the set point of the temperature in the reactor. During the test run, the reactor has been set to different retentions times, which can be seen on the length of the period at 95 C. Test runs with the data loggers have been a central part of the documentation of the temperature and retention time in the reactors. The retention time can be estimated when there is rapid change in the temperature profile (eg feeder to reactor, reactor to container). Page 24/89

25 Enzymatic treatment The pictures in the following illustrate the typical setup used in test of the enzymatic treatment. In the picture to the left, waste is loaded into the feeder funnel. There has been conducted tests on different types of waste (different types of MSW and green waste from source separation). In the picture to the right, Amagerforbænding personal is separating the treated waste using a vibrating sieve. The setup was used to test different configuration of the sieve. An example of treated waste can be seen in the picture above. It is a mixture of solid fraction and bioliquid Parameters that were changed were mesh size, slope and amplitude of the vibrating sieve. Output from the vibrating sieve was a solid fraction with a dry matter of 30-50% and a liquid fraction with a dry matter of 15-30%. Samples of the bioliquid was collected and analysed of eg biogas potential, heavy metals and xenobiotic (se picture below). The bioliquid can be characterised as a brownish liquid with a typically sweet smell of waste. The particles in the liquid are very small due to the enzymatic treatment. This ensures fast digestion in a biogas process. Some key figures: Volatile solids : 17-25% Ash content: 2-4 % ph: ~5 Bio-methane potential: Nm 3 CH 4 / t VS Degree of digestion: 85% of VS Page 25/89

26 5.3 WP8 Procurement and construction of a demonstration plant for waste liquefaction In the start of 2008, the first detailed drawing was sent out to manufacturers for the combined heating, cooling and enzyme reactor. The reactor was constructed to be able to test enzymatic treatment of household waste in large scale. The reactor would treat the waste in batches and be used to make analyses and test both mechanically and chemically. Figure 9 The combined heating, cooling and enzyme reactor ready for transportation to Amagerforbænding The installation was in operation in October 2008 and after a 2-3 months test period the results were used to design the cooling and enzyme reactor for the continuously fed demonstration plant. Both the batch reactor and later the pilot plant were placed at Amagerforbrænding I/S in Copenhagen. The reactor was operating with almost 100% availability, only small adjustment had to be made on the seal between the feeder and the rotation drum for the pilot plant. The seal was made less tight and the material was changed. The test proved that the reactor could be used as the heating reactor and all the desired tests could be performed to finalise the basic design of the complete pilot plant. The test showed that the original assumption that the reactors should be identical was possible but needed a special layout. It was not possible to construct three drum reactors in the layout available for the pilot plant. Tests were therefore performed to investigate whether the cooling system could be made in a different way. This was found possible and the cooling and transport between the two reactors could be combined in a conveyer belt solution. In this way the layout could be modified and fit to the available area at Amagerforbænding I/S. Page 26/89

27 The site where the pilot plant was to be constructed had to be modified to fit the new plant. The foundation for the reactors, transport system and a new floor had to be constructed. Electricity had to be upgraded to the steam generator and the new control room had to be installed. The overhead crane had to be converted from manual to automatic operation. This was performed by Amagerforbænding I/S simultaneously with the equipment being designed and purchased. In the picture to the left is shown the area where the pretreatment was to be placed. Picture below shows the location where the enzyme reactor was to be constructed. In the start of 2009, the detailed drawings for the enzyme reactor were sent to the manufacturer and the discovery from the initial tests led to the size of the reactor as is it is built today, 14m long and with a diameter of 2.5m. The feeding solution used for the heating reactor worked without problems and the same solution was therefore used for feeding the pretreated waste into the enzyme reactor. At the same time, the design of the vibration sieves and cooling section was also started. Test result from over two years of testing led to the specific design of the two vibration sieves placed after the heating reactor and the enzyme reactor. New small-scale tests and modelling had to be performed to evaluate how the waste would react when transported on a rubber belt. After that the final details on the design were made, the large components were ordered and the erection was started in August The erection also included the movement of the heating reactor to the new location. Page 27/89

28 The combined cooling and transport system at its final location. To the right in the picture, the feeding system for the enzyme reactor and the inlet end of the enzyme reactor. The pretreatment was sealed off with the wall to reduce the dust and risk for contamination in the enzyme zone where most of the tests and analyses were performed. The first part of the cooling and transport system. The heating reactor has been moved during erection at its final location. The enzyme reactor and the vibration sieve during erection. The control room was the last heavy component that was lifted into its final location. The equipment for the treatment of the product is of temporarily standard only, until the test runs has shown the character of as well the bioliquid as the solid streams. A small vibration sieve rented from SCAN-VIBRO is in operation for classifying the bioliquid product. It gives valuable data for the later utilisation of the bioliquid. The first test reactor ELSE has been utilised for washing the solid materials after the enzymatic treatment procedure. The data found have formed basis for the design of a washing system. A design group for the washing system has been established, and the first outline of such a system has been made. The washing plant will be put in operation during Page 28/89

29 5.4 WP12 Demonstration and optimisation of waste liquefaction On December , a number of people and journalists were invited to celebrate the start of the test period of the continuous REnescience pilot plant at Amagerforbrænding I/S. Figure 10 Showing the first amount of waste added to the plant during the opening ceremony for the new REnescience pilot plant. It was scheduled that the plant could be in operation during the COP 15 period. As this period started shortly after the commissioning of the plant, a great focus was put on the reliability of the process. The plant was operating as designed, showing the capability to separate household waste into the bioliquid and the solid inorganic fraction. Since the start up in December 2009, the plant has been operating very stable. A number of small stops in the production mostly caused by the modified overhead crane and the steam generator have been observed. But none of the stops have had duration of more than a few hours or days. A high number of tests have been carried out to evaluate all the plant parameters and also to demonstrate the figures foreseen during the design phase. The results have been incorporated in the control system. Today, the plant is operating with such a high reliability that it is possible to switch over the operation and monitoring of the entire plant to operators in the remote central control room at Amagerforbrænding I/S. Personal are further able to monitor, assist and extract data from the control system by connecting via internet Pilot plant The REnescience core process involves non-pressurised thermal pre-treatment, cooling, liquefaction of waste and separation of the degradable bioliquid fraction and the solid fraction. The pilot plant was designed to handle unsorted household waste with a maximum particle size of 300x300mm. The limitation in particle size is due to the overall scale of the pilot plant. In the full-scale plant, MSW can be treated with no limitation in particle size. In Figure 11, an overview of the continuous demonstration plant at Amagerforbrænding can be seen, with steps of the core process indicated: 1. Waste silo 2. Thermal treatment 3. Vibrating sieve 4. Waste transport and cooling system 5. Waste feeder 6. Enzyme reactor 7. Separation sieve Page 29/89

30 Figure 11 Overview of the pilot plant Non-pressurised thermal pre-treatment The first step in the process (number 2 in Figure 11) is a non-pressurised thermal pre-treatment, where the waste is heated with low pressure steam to 95 C for 30 minutes. The purpose of the pretreatment is to open the structure of the biomass to make it accessible for the enzymes in the hydrolysis process. The heating in the thermal pre-treatment is performed with an addition of water to ensure that the biomass is saturated. Access of water is drained off in a vibrating sieve (number 3 in Figure 11) and returned to the boiling reactor. In the boiling reactor the waste is prepared for enzyme addition. Before the hydrolysis step, the waste is cooled on a conveyer belt with air to approximately 50 C (number 4 in Figure 11). Enzymatic treatment Following the non-pressurised pre-treatment, the next step in the process is the hydrolysis of the liberated starch, cellulose and hemi-cellulose (number 5 and 6 in Figure 11). If the purpose of the enzymatic treatment is to prepare for the fermentation, a large number of different enzymes with different modes of action are needed to produce monosaccharide. In a traditional ethanol production process based on straw, one of the major costs is the consumption of enzymes. If the purpose is only a liquefaction eg for biogas production or direct gasification substantially less enzyme is required, and the enzyme costs will be reduced. Thus savings are possible, compared to the fermentation process. For enzymatic treatment of waste, enzymes for lipids and proteins may be needed together with enzymes for breakdown of the sugar components ie cellulose, hemicellulose, starch and pectin. Separation Separation of the liquefied fractions from the non-liquefied solids is carried out by vibrating sieves in one or more steps depending on the exploitation of the downstream products (number 7 in Figure 11). The vibrating sieve separates the liquid and solid fractions. Page 30/89

31 5.4.2 Experiments in continuous process The first period was focused on process control and calibration of the plant. This was a challenging task as the retention time and the total volume waste in the plant were high. Some of the measurements had a high deviation, some due to manually handled measuring stations, and other due to very few measuring points. A great effort had to be made to get the mass balance to fit the theoretical figures. After a few months, all the measuring instruments were calibrated and personal educated and trained in handling the measuring equipment and the methology. Hereafter the first tests could be performed. Also in the continuously fed plant all tests were carried out according to DoE. In the first test runs some of the set point and operation modes had to be set to also test the mechanical design. By making the uncertain operational set points early in the test run, the plant design could be adjusted without jeopardising many days of testing. The main focus on the experiments setup was to step test the plant. In a step test a disturbance is made to one of the vital control parameters and register the effect. In this way it is possible to map the characteristic of the process and the dynamics. In June and July 2010, the experimental focus was to find the optimal process conditions for the biogas experiments that were planned in the autumn. The aim was to keep a stable production without interuptions and to be able to keep an constant DM of the bioliquid. As the plant at Amagerforbrænding was operating almost all hours around the clock, a full time engineer was employed to the test facility for taking care of the tests and being responsible for the maintenance and service work Steam economy optimisation There has been a constant improvement of steam economy over the plant s lifetime. Several tests have been performed to quantify and reduce the amount of steam used. The main challenges have been to measure and keep the amount of waste constant and to control the temperature through the boiling reactor. A challenge was also to control the steam generator. At the small amounts of steam that were used, the steam generator s cleaning process was too high in the beginning and may have affected the results in the first test runs. There are still improvement possibilities in the pilot plant to improve steam economy. One of these is to insulate the vibration sieve after the boiling reactor. The seal between the boiling reactor and the cooling plant did not work properly at the start and was hard to solve mechanically due to the rotation outlet and vibrating sieve directly attached to the reactor. The seal was shifted to a tight ring of rubber that followed the rotating drum. There is no indication that the seal has to be shifted again Mechanical test After one year in operation visual, internal inspection was made of all components, the welding of the enzyme reactor was inspected with ultra-sonic testing. No exceptional corrosion or erosion problems was found. Reliability test One of the very important factors for future plant is a high reliability, and it was important to find the limitations for each component. This was done be allowing long uninterrupted operation periods with normal conditions and large load changes. By this, the plant s limitations could be found, such as tearing of seals, erosion and corrosion to metal parts, risks that waste was blocked in some part of the plant or accumulation of compounds or small objects that over time will block the circulation pumps. Page 31/89

32 It was also important to find the minimum and maximum loads for the plant. The plant was run with very low capacity and with high capacity slowly stepping up to see how the plant reacted. Load capacity Early in the process, it was discovered that the load capacity of the enzyme reactor could be increased by changing the gear motor for the rotation of the reactor. After the gear motor had been changed the load was slowly increased to be able to find the maximum capacity. It is a known phenomenon that rotating reactors can form an unbroken core of the rotating material. When treating waste, this core will be wrapped with plastic and textiles and will over time form a large waste braid. It was found that during load changes at high load, there is a high risk that this kind of braid is formed. This was found to be the limiting factor regarding the load capacity Vibration sieve, mesh sizes The amount and the particle sizes of bioliquid were evaluated be changing the mesh sizes in the vibration sieves. Feeding waste to the plant One of the big challenges with waste, as a material, is the unconformity and the variable sizes. During the first year, many fine adjustments have been made to the feeder of the fresh waste. The adjustment has been to tune the amount of waste that has been added in every sequence and the length and the pressure used in every push. In this small plant there is an increased risk with long textiles such as towels and nylon socks that can get stuck around corners. This risk is reduced in a large scale plant when the cross section in the entire plant is bigger Boiling test A couple of boiling tests were performed to evaluate the effect of boiling time, water content and temperature. The tests were evaluated by monitoring the dry matter content, ph-value and amount of bioliquid and the dry matter and the ph value of the recirculated water Enzymatic treatment No enzyme optimisation was made in the continuously fed reactor. The optimisation was made in small-scale lab tests. The experiences were tested and evaluated in the pilot plant. The bioliquid from the pilot plant was logged and measured in terms of dry matter, ph-value and amount of produced bioliquid. The theoretic value and the received valued were compared and studied in a mass balance as shown in Figure 12. Page 32/89

33 Figure 12 Mass balance extracted from the model used to evaluate the process Bioliquid samples Every day that the plant had been in operation, a sample of bioliquid was collected. The sample was directly frozen and then later examined. The samples from each weak were mixed so that the composition from one weak of production could be evaluated. Figure 13 DONG Energy personal taking bioliquid samples from the enzyme reactor. Page 33/89

34 5.5 WP6 Continuous liquefaction of straw When the project application was created, it was expected to take some time before production of bioliquid from household waste would be developed to a stage where steady production for test runs on several gasification technologies was possible. Therefore liquefied straw was seen as a reasonable way of gathering experience in gasification of bioliquid. But the development of the REnescience liquefaction process on household waste gained so much momentum that is was agreed to level down the liquefied straw as a test media and concentrate fully on the bioliquid from household waste. Therefore, no liquefied straw was produced for co-gasification tests with coal. In the project description change agreed on May 2010, WP 6 was cut down in budget to 1/3 of the original budget. One new task was introduced regarding bio-gasification of Inbicon's C-5 liquid 3. The REnescience bioliquid contains mainly C6 sugars (glucose) while the Inbicon C5 liquid mainly contains C5-sugars, such as Xylose. Only few microorganisms are capable of converting both sugars. The test was planned to be run in Foulum, but due to the number of biogas tests necessary to be run in WP 4.2 and WP 6, it was most cost effective to invest in own biogas test equipment. This new equipment was purchased and installed and the biogas potential of mixtures of Inbicon's C 5 liquid and REnescience bioliquid was tested. Test setup and results from the biogas test is shown in Table 2. The actual reached bio-methane yield of the mixtures is shown in column 3, while the theoretical bio-methane yield of the mixture is calculated in column 5. The difference between these two is shown are shown in column 6. Table 2 Biogas test results Test (g C 5 : g bioliquid) ml CH 4 /g DM Average value Standard deviation Ino Ino Ino Only bioliquid Only bioliquid Only C Only C :2 (C 5 / bioliquid) Expected biogas yield. ml CH 4 /g DM 6 Synergy ml CH 4 /g DM 2:2 (C 5 / bioliquid) :3 (C 5 / bioliquid) :3 (C 5 / bioliquid) :1 (C 5 / bioliquid) :1 (C 5 / bioliquid) :3 (C 5 / bioliquid) :3 (C 5 / bioliquid) Inbicon is like REnescience a subsidiary company to DONG Energy producing second generation ethanol. Page 34/89

35 The results show no detectable synergy in co-fermenting C 5 liquid and REnescience bioliquid; rather the opposite effect. A reason for this can be that the bio-culture that works well on the REnescience bioliquid is not suited for converting the Inbicon mixture. To adapt the bio-culture to both REnescience bioliquid and the Inbicon C 5 liquid, if possible, a continuous working biogas process is necessary. Page 35/89

36 5.6 WP4.1 Supercritical gasification test of liquefied straw and waste, lab. scale The Danish company SCF Technologies has developed a method for converting a liquid biomass stream into mainly bio-oil through near-supercritical reactions. The process is called CatLiq. This technology could be a shortcut to convert the REnescience Bioliquid into a transport fuel. Therefore is was decided to test REnescience Bioliquid in the CatLiq process to evaluate if this could be a feasible alternative to either normal pressurised gasification or bio-gasification. As described in section 0, WP 6, it was expected to take some time before production of bioliquid from household waste would be developed into a stage where steady production for test runs on several gasification technologies was possible. Therefore, liquefied straw was seen as a reasonable way for gathering experience in gasification of the bioliquid. But the development of the REnescience liquefaction process on household waste gained so much momentum that is was agreed to level down the liquefied straw as a test media and concentrate fully on the bioliquid from household waste Objective The purpose of this work package was to study the conversion of bioliquid in the CatLiq pilot plant ( Figure 15). The study was not a complete evaluation but merely an initial study to evaluate the potential of processing this material in the CatLiq process. Liquefied household waste has not been evaluated before and it is in some aspects different from the materials that previously have been processed in the CatLiq pilot plant. The work consisted of two phases: 1) An initial phase during which the conversion was studied in a batch high pressure cell and 2) A trial phase during which the material was processed in the pilot plant Background to the CatLiq technology CatLiq is a technology for converting wet biomass to bio-oil with high heat value. No drying of the raw material is required; on the contrary, water is an important reactant that catalyses the oil formation. In the CatLiq process the organic fraction of the feed stream is converted into oil in the presence of a homogeneous (K 2 CO 3 ) and a heterogeneous (Zirconia) catalyst, at subcritical conditions ( C and bar). The full product consists of a bio-oil, a gas-phase mainly consisting of CO 2, a water phase with soluble organic compounds and a solid bottom-phase mainly consisting of inorganic matter. Figure 14 The CatLiq process Page 36/89

37 Figure 15 The CatLiq pilot plant Figure 16 The CatLiq batch reactor Prestudy The initial study was carried out to investigate oil formation from liquefied waste and to monitor the effect of parameters such as temperature and protein addition. The experiments were carried out without heterogeneous catalyst, since it cannot be kept suspended but remains on the bottom of the container. All trials were carried out with a residence time of 40 min, corresponding to a flow rate of 13l/h in the CatLiq plant. An initial pressure of bar of N2 was applied. The pressure increases during heatup and ends at approximately 250 bar, identical with the working pressure in the CatLiq plant. The trials in the batch cell only give an indication of what parameter settings to use in the pilot plant. The relatively rapid heat-up in the CatLiq plant in comparison with the batch cell is one of the major differences. Others are the absence of Zirconia and recirculation in the bath reactor. However, it can with certainty be concluded that high temperature and protein addition have a positive impact on oil formation and oil properties when converting the bioliquid. The implications for the parameters to be used when processing bioliquid in the pilot plant are: The process temperatures should preferably be above 365 C. The K2CO3 addition should be at least 0.10g/g dry matter Protein in some form should be added, however, the addition should be minimised No major difference between gluten or casein addition Pilot study After the prestudy, trials were carried out in the pilot plant. Originally, it was decided to perform 16 runs and 100 hours of operation; however, this proved impossible due to problems with the high pressure feed pump and oil/salt separation problems. Therefore, only half of the initially agreed operation time was reached. However, the total time required including troubleshooting was more than 100 hours. The bioliquid, unlike materials previously evaluated in the CatLiq pilot plant, contained a large fraction of rather large hard particles consisting of glass and metal. These disrupted the action of the ball valves in the feed pump. A lot of effort was put in pre-treatment as well as modification of the Page 37/89

38 feed pump. The content of inorganics/ash in the liquefied waste was relatively high in comparison with other feeds used in the CatLiq plant. Therefore, an intensive pre-treatment of the REnescience bioliquid was conducted prior to the tests. The optimised pre-treatment can be described as follows: 1. Filtration 2 times with 0.8mm filter 2. Addition of protein 3. Milling in bead mill with 6mm steal beads, residence time 3 min, 800rpm 4. Addition of 15% K2CO3 based on dry matter to increase ph above Using a 0.3mm feed filter. Six test runs were conducted. The setups for these are shown in Table 3. Table 3 Test runs made in the pilot plant Already from DONG 1, it was early observed that the produced product (full product) contained a large quantity of inorganic compounds and no obvious oil phase as is normally the case (Figure. 10). Centrifuged samples contained an opaque water phase and a brownish bottom phase, but still no oil phase (Figure. 11). The product though had a typical CatLiq oil smell. When centrifuged in the 2 L desk-top centrifuge, the water could be removed leaving a compact bottom phase with a clay-like appearance (Figure. 12). It was obvious that this clay contained the adsorbed oil. From all other DONG experiments the same pattern was observed with a clay-like bottom phase in which the oil was adsorbed. Page 38/89

39 Figure 17 Showing results from the tests It was concluded that the oil could be released from the clay bottom phase by heat and centrifugation or by extraction with some proper solvent, in this case ethanol. With heat and centrifugation no complete removal of the oil was achieved, whereas extraction with ethanol seemed to give a more effective oil recovery from the bottom phase, even though it required repeated extractions. The water phase was much cloudier than is normally seen when running on other materials. It contained a large amount of suspended salt, some of it remaining also after centrifugation. The levels of total organic carbon in the water phase were somewhat higher than in runs with DDGS, (Distillers Dried Grain and Solubles, rest product from grain based ethanol production) Conclusion It was demonstrated that oil could be produced from liquefied waste. The oils from DONG 1 to DONG 5 had a heat value of 35MJ/kg, which is in line with other raw materials processed at the CatLiq pilot plant. DONG 6 and 7 had values of just 30MJ/kg. In general, two major challenges appeared when processing the liquefied waste: 1) Severe problems with the operation of the high pressure feed pump occurred due to particles in the waste. The particles consisted of glass, metal and stone and it was not straightforward to remove or eliminate them. In the end, a combination of improved filtration, milling with large beads and modification of the feed pump solved the problem. Page 39/89

40 2) The product was different from what has been the case when other materials, such as DDGS, have been processed in the plant. Instead of a top-phase of oil, an aqueous middle phase and a bottom-phase, consisting of salt, the oil this time was adsorbed on the inorganic particles. The oil could be separated from the inorganic phase by centrifugation in combination with heat or by extraction and evaporation, however, those procedures were time consuming and a proper mass and energy balance could therefore not be established. The behaviour has not been seen before and probably has to do with the composition of the inorganics in the sludge, which were rich in for example silica and aluminium. These elements most likely come from glass, metal, stone and other minor sources. The milling of the feed might also have contributed by producing very small particles of these relatively insoluble compounds. It seemed like that the particles were too small to be trapped in the salt trap and therefore continued through the process together with the oil product. REnescience s conclusion of the results from the SCF test is that the SCF process is not suited for treatment of bioliquid. Several issues both of mechanical, process related and economic art disqualified the SCF process as feasible for treatment of the REnescience bioliquid. Page 40/89

41 5.7 WP4.2 Scanning of biogas potential from the bioliquid The purpose of the study was to measure the biochemical methane potential of the liquefied biogenic MSW material. The methane potential trials are measuring the methane potential after extended anaerobic digestion and also comparing the difference between thermal treated waste to thermal and enzymatic treated MSW, bioliquid. Bioliquid analyses show high amounts of Volatile Fatty Acids (VFA) such as acetic acid, and in total we find 19grams/litre of VFA in bioliquid (Table 4). In the thermal treated waste (control) we find a VFA concentration of 5 g/l. Concurrently, the control has a higher concentration of propionic acid, which is considered an inhibitory VFA or rather an indicator of anaerobic digestion failure. Overall the VFA concentration in the bioliquid fraction is higher than what we find in the control. Table 4 Analysis of volatile fatty acids (VFA) and sugars in bioliquid and control. n.d.: not detected VFA type Inoculum (mg/l) Control (mg/l) Bioliquid (mg/l) Acetic acid C 2 H 4 O 2 (mg/l) Propionic acid C 3 H 6 O 2 (mg/l) methylpropionic acid C 4 H 6 O 2 (mg/l) Butanoic acid C 4 H 8 O 2 (mg/l) Pentanoic acid (valeric) C 5 H 10 O 2 (mg/l) Methyl butanoic acid C 5 H 10 O 2 (mg/l) Total VFA content Sugars (g/l) (g/l) (g/l) Cellobiose (g/l) n.d Glucose (g/l) n.d Xylose (g/l) n.d Lactate (g/l) n.d Not surprisingly, the sugar content in bioliquid is much higher than the control (Table 4). Sugar is also one of the products of the first step, hydrolysis, of the anaerobic digestion. The fact that the bioliquid is pre-hydrolysed biomass means that the hydrolysis of the anaerobic digestion is unnecessary and will be surpassed. Bioliquid to methane is therefore moving through fewer steps, whereby the retention time is lowered. Anaerobic digestion trials are conducted as complete digestion trials in triplicate. The inoculums used in these trials are adapted to nonhydrolysed biogenic MSW and wastewater sludge and collected at a nearby municipal wastewater facility. Bioliquid ph is around 5.0, which is below the optimal anaerobic digestion ph between 7.5 and 8.0. No antagonistic effect is found when adding bioliquid to anaerobic digestion. The buffer capacity of inoculums is high and neglects the low ph of the bioliquid. Lowering the ph in anaerobic digestion may have a positive effect as it serves to lower the ammonium shift to ammonia. Ammonia is inhibitory to anaerobic digestion. Page 41/89

42 The control is mixed with bioliquid or used alone in the digestion trial setup to evaluate the possible performance contrast of these two substrates (Table 5). The gas production from the (100%) bioliquid has decreasing gas production from first gas release until day 19th after which it increases and decreases again. The 100% control samples show a clear increase in gas production until day 10 from which the increase in production rate ceases. The inoculum may well be better adapted to the control compared to the bioliquid. The gas production is comparable even though the bioliquid samples show initial lag phases. The high amount of acetate in the bioliquid may call for a mobilisation of acetoclastic methanogens that possibly will cause the observed lag-phase. This splitting of acetate is important as it accounts for approximately 70% of methane production, the remaining 30% coming from CO 2 and H 2 methane formation. Table 5 Experimental design. Content of MSW bioliquid and/or MSW control of the samples. Average sample ph and methane production is also provided n=3. Different letters describe significant difference among groups; there is no statistical significant difference (P=0.661) Group with three replicates each MSW bioliquid (%) MSW control (%) Average initial ph Methane production (ml/g VS) 1 Blank (Inoculum) A A A A A The cumulative methane production of samples with 75% bioliquid and 25% control reaches the highest gas production with a steep and linear increase until the 28th day similar with 100% bioliquid and with 100% control samples (Table 5). Samples with 50% control and samples with 75% control show a midterm cease in gas production at day 19. It may be due to a fast utilisation of enzymatically treated material in the bioliquid part before moving on to the hydrolysation of nonhydrolysed control material. Page 42/89

43 Cumulative methane (ml/g VS) Slurry 100% Slurry 75%, Fibre 25% Slurry 50%, Fibre 50% Slurry 25%, Fibre 75% Fibre 100% Day Figure 18 Cumulative methane production for the 90 days of digestion. Please note that the methane production of the inoculum is not shown in this graph. Inoculum gas production has been subtracted from the other samples. Gas release was performed at day: 3 and 10. Average final yield in this study is 360ml CH 4 /g VS and the highest yield is the mixture of 75% bioliquid and 25% control sample with 385ml CH4/g VS (table 2). The theoretical methane potential is calculated as 350ml CH 4 /g Chemical Oxygen Demand (COD) giving that the theoretical potential is 452ml CH 4 /g VS for bioliquid samples and 507ml CH 4 /g VS for the control samples (table 4). This means that 25 75% control bioliquid sample has a theoretical potential of 466ml CH4/g VS, whereby the result is 83% of theoretical potential. The 100% bioliquid sample ended at 346ml CH4/g VS, which is 76% of theoretical methane potential. The statistical analysis showed, however, no significant difference among the treatment groups (P=0,661) (Table 5) Test II Test II was performed in an inoculum from Grindsted and Fredericia municipal wastewater treatment plants (Fredericia Spildevand A/S). This test concerned the loading of biogenic substrate to the respective batch and the inhibitory effect of loading. The test was performed on an automatic methane potential test system allowing the dynamic biogas production to be monitored. The system also includes a CO₂ capture prior to the volumetric gas measure. Thus, the capture and measure system ensures the measure of only the methane production. The test setup involved three different VS loadings: 5g VS/l, 10g VS/l and 15g VS/l with three replicates per loading, three inoculum blind tests and three control tests with pure cellulose. Test is performed at mesophilic temperature at 38 C. Results show that the bioliquid performs equally well considering the loading difference. The batch system does not seem to be inhibited by the increased loading from 5 to 15g VS/l biogenic loading (Figure 19). The test shows that 95% of the methane potential of the bioliquid was reached within 7 days and 12 days for the fraction containing more fat (Figure 19). Page 43/89

44 Figure 19 Dynamic methane potential test of REnescience bioliquid at different biogenic loadings. REnescience High fat samples are made from industrial diary waste. Through the automatic methane tests we find that the methane potential is 350Nm3 CH 4 /ton VS. The REnescience High fat samples were bioliquid from the treatment of MSW similar industrial waste and especially containing waste from butter production at a local dairy. These high fat samples show a methane potential of 400Nm3 CH 4 /ton VS. The fast digestion of seven days is completely contrary to the current MSW anaerobic digestion plants where the retention time is often above 20 days. Lower cost of anaerobic digestion plant is a consequence of the decreased retention time of bioliquid. The decreased retention time means higher gas production per volume of digestion chamber/tank. However, the low retention and thereby the high organic loading rate that will be a consequence of low retention time, will mean that the digestion plant has to be built with a effluent filtration unit. The filtration unit will ensure that the microbial biomass is retained and kept inside the digester. The high loading rate causes the microbial biomass to follow the effluent due to the high flow of liquid media Conclusion We find that enzymatic MSW bioliquid is a potential biogas substrate that shows no antagonistic effect even with or without the co-digestion of small amounts of non-hydrolysed material. Provided a better understanding of the interaction between the feedstock composition and the anaerobic digestion, it may show beneficial to use the enzymatic processing of MSW to optimise the methane production from MSW. Future trials will show the effect of continuous bioliquid feeding and the effect of co-digestion with eg animal manure. Bioliquid has a very short digestion time and thus a short conversion time of biogenic mass to methane. Page 44/89

45 5.8 WP4.3 Full scale tests in Fredericia Rensningsanlæg (Fredericia Spildevand A/S) Purpose of fermentation trial at Fredericia Spildevand A/S The purpose of adding REnescience bioliquid to the 4000m3 Anaerobic Digestion (AD) reactors at Fredericia Spildevand A/S was to verify the lab results from test II in full scale, and to test for other effect eg foaming, viscosity change, sludge dewatering etc Full-scale test The full-scale trial was performed on 15 September m 3 of REnescience bioliquid was produced on REnescience pilot plant at Amagerforbrænding. The bioliquid was based on MSW from Holsterbro collected by nomi A/S. The bioliquid was supplied as an addition to the normal flow of waste water sludge (5m 3 /h). The bioliquid was bypassing the Cambi hydrolysis prior to the AD treatment. In an hour from 11:40 pm the bioliquid was added to both AD reactor 1 and AD reactor 2. Figure 20 shows the immediate results on the biogas production. The dark blue and the red lines show the biogas production from AD reactor 1 and AD reactor 2. To find the total biogas production the biogas production from AD reactor 1 (RT1) and AD reactor 2 (RT2) has to be added. Figure 20: Biogas flow from AD process at Fredericia Spildevand A/S Figure 20 indicates a significant boost of the biogas production almost immediately after supplying the bioliquid. The biogas production increases from an average of 175m 3 /h (addition of RT1 and RT2) to a maximum of 250m 3 /h at 1:30 pm less than an hour after the supply of bioliquid has Page 45/89

46 stopped. After this, the biogas production is decreasing but still higher than before addition of bioliquid. By summarising the extra biogas production for the first 24 hours after addition of bioliquid, the total biogas production related to the bioliquid is found. Assuming methane content at 63% the bio methane yield for the bioliquid is found to be 68m 3 bio methane/m 3 bioliquid. With dry matter content at 20% and VS at 17% for the bioliquid, the specific bio-methane yield for the bioliquid addition is 400m 3 /ton VS. This level of methane yield is very high compared to other biogas substrates and also in the high end of yields achieved in lab scale tests. Regarding the none-yield properties, like foaming viscosity etc., no kinds of complications related to the addition of REnescience bioliquid were seen Conclusion So, if it is possible to draw any conclusion on a single trial, the conclusion must be that the bioliquid is highly potent for biogas production also together with waste water sludge, and that cofermentations with waste water sludge seem uncomplicated. REnescience has through this biogas trial and lab tests been confirmed in the assumption that co-fermentation of bioliquid and waste water sludge is a very promising way of combining waste water treatment and MSW handling. Both tests also indicate a possible synergy of the combined fermentation, meaning that the total biogas production at co-fermentation is higher than what can be reached by separate fermentation. This is a possible positive effect that has to be documented through more trials. Page 46/89

47 5.9 WP16 Products and system evaluation WP 16 was not a part of the original project description. It was formulated in relation to change of scope in the spring The main scope of WP 16 was to generate more knowledge of the products generated in the REnescience process and how the REnescience process can be integrated in different energy scenarios. Many aspects of the bioliquid are handled in different parts of this rapport why the main focus here is utilisation of the solid fraction Handling the solid fraction washing and sorting The solid fraction coming from the hydrolysis contains approx 30-40% of the bioliquid produced. In order to obtain a high biomass recovery (aim for 95%) it is necessary to do further processing of the solid fraction. The first type of processing to be investigated is initial washing and sorting of the solid fraction. The goal within the frames of the PSO project was to design the equipment for this washing and initial sorting of the solid fraction. The design face was initiated with a series of small-scale tests and a test in an existing equipment rented from a supplier. This work did take more effort than expected and ended up taking six months longer than estimated Initial tests In the initial design phase with idea generation, two different washing approaches came up. The two approaches that were identified, was a drum washing and washing in a dewatering unit normally used in wastewater treatment. The initial test was split in two to cover both approaches. Drum washing Our lab scale reactor ELSE was used to simulate washing in a drum washing unit. In order to minimise the water consumption a setup was created that should simulate counter current. Setup for washing in ELSE 75 kg solid fraction kg 1. rinse water kg 2. rinse water kg water Solid fraction Solid fraction Solid fraction - Weight 1. rinse water - Weight - Dry metter 2. rinse water - Weight - Dry metter 3. rinse water - Weight - Dry metter The rinse water from the first repetition of the setup above was stored. The setup above was repeated again using the rinse water from the first setup. The setup then repeated once more (three repetitions in total). By doing this, the rinse water was concentrated and the relation between DM in the washing water and its ability to obtain more DM from the solid fraction could be evaluated. Page 47/89

48 Some of the results can be seen in the Figure 21. The horizontal axes are grouped in three in the relation to the first, second and third rounds of washing each containing the three portions of rinse water. From the graph it can be seen that the concentration of DM in the first portion of rinse water reaches almost 10%. It can also be seen that the amount of DM increases in the third portion of rinse water as the washing effect in the first two steps is reduced due to increased DM in the washing water used. Figure 21 Test result for washing of the solid fraction in ELSE. It has also been identified that the water used in the first washing step should have a starting DM content below 7-8% in order to have sufficient capability to obtain more dry matter. On the picture below. the solid faction after washing can be seen. The solid fraction after washing in three steps can be seen in the picture to the left. Key findings: With 3 washing steps more than 90% of the bioliquid sticking to the solid fraction can be washed of. The dry matter in the 3 portions of washing water can be as high as 10% DM The water used in the last washing step has to be with a starting dry matter content below 0.5% to obtain an sufficient washing effect The overall impression of washing in a drum is very positive. It has been indicated that 3-4 washing steps are needed to obtain 90% recovery of the DM on the solid fraction. The only concern is related Page 48/89

49 to the perforated drum and blocking of the holes. Another disadvantage is that there is no separation of the solid fraction during the washing process. Washing in a dewatering unit The equipment manufacturer ReTec constructs a washing unit for washing tree roots. The construction of this washing unit was similar to what came up in the idea generation. A semi-manual version of the washing unit was therefore rented at ReTec and tested at the pilot plant (a picture of an automatic version can be seen in picture Figure 22). The unit consisted of a 14m 3 vat (traditional container) equipped with a large rolabar rake conveyor (se picture below to the left) in one end and container doors in the other end. The washing unit/container was filled with water and portions of 250kg solid fraction form the hydrolysis was added and washed. The pictures below are from the washing and can to some extent document the effect of the washing and separation of the solid fraction in a floating (light fraction) and sinking (heavy fraction) fraction. Adding water to the washing unit. The rolabar rake conveyor consists of a chain conveyor with large metal spikes. The first part of the floating fraction removed from the unit. The DM content in the washing water was at this point <1%. The last part of the floating fraction removed from the unit. The DM content in washing water was at this point 2.4%. Figure 22 Washing in dewatering unit After washing the 4*250 kg solid fraction, the water was drained off and the sinking fraction became visible. Page 49/89

50 The DM content in the washing water was approx 1% after washing of the first 500kg solid fraction. The floating fraction that was generated was almost completely free of bioliquid. The ratio between water and solid faction was approx 28/1 in this setup which explains the high washing ability (in the setup with ELSE the total ratio of water and waste was 6/1). To obtain a more realistic picture of the washing ability, 450kg of bioliquid (DM 15%) was added to the unit. The DM in the washing water increased hereby to approx 2%. Another 2*250 kg solid fraction was added and washed. After these two portions were washed, the DM in the washing water increased to 2.4%. It was very clear that the washing ability was reduced considerably when the DM in the washing water came over 2%. A key learning from the experiment is therefore that the washing unit must be equipped with a recirculation setup that extracts DM from the washing unit. By visual inspection it was assessed that the floating/sinking separation worked fairly well and that it was worth including in a washing unit. The setup using a tear to get the floating fraction out of the vat might not be the best solution. During the test it was observed that plastic foil and textile had a tendency to get stuck in the spikes of the rolabar rake conveyor The design After the two test runs were completed, a new idea generation was arranged. At the end of this process it was decided to work in the direction of a washing unit similar to the one tested from ReTec (see Figure 23). Water-based gravitational separation system from ReTec for separation of light and heavy materials such as woodchips and stone/sand ( Figure 23 Showing washing and separation system from ReTec. Schematic drawing of the washing/separation unit for ReTec. There were indicated some issues that had to be changed in the original design from ReTec to fit the unit to be used for washing of the solid fraction. The setup with the rolabar rake conveyor was changed to a traditional conveyer belt The zone for gravitational separation was increased A setup for recirculation the washing water was added To ensure transport of the floating from the input point to the conveyer the recirculate water was flushed in direction of the conveyer Page 50/89

51 To optimise the gravitational separation a setup was added that made it possible to inject an air/water mixture in the washing unit. It was decided to let ReTec make the first sketch of the new washing unit. During this process,regular design meetings were held where sketch was presented and discussed. The result of this process can be seen in Figure 24. Figure 24 Final design of the washing plant In Match 2011, it was decided to order the washing and sorting unit at ReTec. The installation was planned to be at the end of May The construction of the washing and sorting unit/equipment was covered by the EUDP project REnescience Waste Refinery. Due to delay in design, construction and commission of the equipment, only a few results were generated in the period of the PSO project. Due to this, it has not been possible to generate washed fractions for test in other sorting systems and for test of storages stability of RDF made from the washed fraction. After the first test in the washing equipment it has also become clear that more than one washing step is needed to reach a sufficient quality of the solid fraction if further processing should be possible Heating waste with water instead of using steam The pilot plant at Amagerforbrænding is presently heated with steam which is produced by a steam generator. To be able to optimize the usage of water and to be able to connect the REnescience plant to an existing plant, the steam and the washing water needs to be re-circulated. A setup was constructed where steam was injected in a vessel with re-circulated water. This water then was used to heat the waste in the heating reactor. A couple of boiling tests were performed using the heated re-circulated water as the heating media. Results from these tests indicates that it is possible to heat the waste using water instead of steam, but further test are necessary before final conclusions can be drawn. Page 51/89

52 5.9.3 Using the bioliquid for incineration or gasification The first investigation indicates that it will not be feasible to first dry and then incinerate or gasify the bioliquid. If the bioliquid is to be dried it can be done in an evaporator. It is important to notice that the bioliquid contains large amounts of sugar that has a tendency to caramelize and therefore is a challenge. The best way to process the bioliquid is in a wet process (biogas or fermentation). In combination with some of the first tests with washing of the solid fraction it was found that by filtration of the washing water a fibre fraction could be isolated. This fibre fraction can by pressed to a dry matter content of approx 45% and is hereby transformed into a material that is similar to masonite. This fraction could be dried further and then used for incineration of gasification. A similar fibre fraction can be isolated from the bioliquid. Depending on the degree of hydrolysis, this fibre fraction can be increased or reduced. When the bioliquid is used for biogas production, the main part of the dry matter is digested. The remaining fraction after biogas production can be dewatered, dried and used for incineration. More investigations are needed to determine if the fibre fraction in the bioliquid and washing water should be extracted before or after the biogas production. If the fibre fraction is poorly digested in the biogas process it makes sense to remove it before the biogas production. When the fibre fraction is extracted from the bioliquid it will contain sugar and organic acids that can easily be digested in a biogas process (the biogas potential is reduced). It must therefore be evaluated if the fibre fraction from the washing water and bioliquid in any way inhibits the biogas process. If not, it makes more sense to extract a fibre fraction after the biogas process. This issue will be evaluated in the individual setup that the REnescience process will be a part of Waste inputs and value outputs This section describes the in- and outputs from the REnescience process. First, the different kinds of waste, which can be treated in the REnescience process, are described, and then the outputs from the REnescience process are described Feedstock This section describes which kinds of waste types the REnescience process can handle. Though the input to the REnescience plant is mentioned as MSW, the REnescience technology can handle a large number of different waste sources. This could be: Unsorted or source segregated MSW Industrial waste fractions containing organic compounds Waste from agriculture (low lignin) Waste from market gardens Waste from retail business, restaurants etc. Landfill recovery Etc. The REnescience technology is very strong in handling waste fractions with mixed organic materials, paper and inorganic material. Page 52/89

53 The output from the REnescience process varies with the input waste composition. A typical Danish MSW composition is shown on Figure 25: Metal; 3% Glass; 3% Noncombustible rest; 5% Combustible rest; 15% Food waste; 42% Nonrecyclable plastic; 7% Recyclable Pastics; 2% Dirty paper and cardboard; 10% Cardboard; 2% Clean Paper; 11% Figure 25 Typical Danish MSW composition (Riber et. al. 2009) The composition of waste shown on Figure 25 is used for reaching the output figures presented in this report Outputs from the REnescience process This section describes the quantity of the output products from the REnescience process. The REnescience process generates three main outputs: A bioliquid containing the biodegradable part of the MSW One or two solid flows. Recyclables containing metals and inert material The main input flows to a REnescience process are MSW and water. The REnescience process uses less than 1m 3 of water to treat 1 tonne of MSW. Brown water (WWT effluent) or other precleaned but not necessary clean water can be used in the process. On the output side almost all biodegradable organics are found in the bioliquid. Despite the high dry matter, the liquid has very low viscosity. The solid fuel consists mainly of plastic, and has a high heating value. The solid fraction is in the REnescience process split in two fractions, where one is a pretty clean plastic fraction with very high heating value. Two recyclable products are leaving the REnescience process. One is a metal fraction and the other is an inert fraction suitable for road building material etc. More recyclable fractions can be obtained by adding further sorting equipment to the process. This is outside the REnescience core technology. A further description of what is inside the REnescience core technology is found in WP Bioliquid The bioliquid contains up to 95% of the digestible organic content of the MSW. The most obvious use of the bioliquid is shown in Figure 26: Page 53/89

54 Figure 26 Utilisation of bioliquid The biogas produced from the REnescience plant can then be used for power (and heat) production by gas engines. This is a high efficiency at low cost conversion of biogas to energy. The typical electric efficiency of a gas engine is 40%. If the REnescience plant is located near industries using steam the biogas can replace natural gas or oil in their steam boilers. Another option is to upgrade the biogas to natural gas quality, compress it and sell it to the natural gas grid. This option enables a high efficiency use of the gas, a flexible fuel for power production in peak consumption periods. Furthermore, the upgraded gas can be used as a green fuel in the transport sector to replace fossil fuel. The REnescience bioliquid can also be used for second generation bioethanol production because of the high carbohydrate (mainly glucose) content. The ethanol can be used as a fuel for the transport sector. The fermentation process to ethanol has been tested with success by REnescience. The sludge after biogas production will contain most of the phosphor and other fertilisers from the MSW. Several technology providers offer equipment for extraction of these for production of concentrated bio-fertilisers for agricultural use RDF (Refuse Derived Fuel)/SRF (Specified recovery fuel) The REnescience process produces a solid fuel product with high energy content. This product consists mainly of soft plastic and plastic containers. PVC and other hard plastics will typically not be found in this fraction. The product will typically have water content around 30% but can be dried, if necessary. With 30% water the lower heating value will typically be 18MJ/kg. Page 54/89

55 Figure 27 Utilisation of RDF/SRF The RDF is almost too good for normal waste-to-energy plants, but can, of course, be treated there. A better solution is to sell the product as a RDF/SRF fuel for power plants or cement industry. The fuel is very low in alkali content, and can therefore be used for high efficiency energy production. The benefit is a power efficiency increase from typically 25% to 42% improving the revenue from power generation. Furthermore, the RDF/SRF can be baled and stored and therefore nationally and internationally traded as other fuels such as coal and wood pellets. MSW is normally considered to be a fuel that must be used in the same pace as it is collected. By extracting the RDF fraction from the MSW it opens up for the opportunity to store a large part of the energy in the MSW and use it when there is a need for electricity in the energy system (as substitution for coal). Another opportunity is to recycle plastic fractions from the fuel and send the rest to a waste to energy plant (WtE plant). The plastic recycling could require process steps outside the REnescience core process Solid fuel The REnescience process is producing a small flow of solid fuel with low energy content. At 60% dry matter this fuel will typically have a LHV at 7MJ/kg. By increased dewatering, the heating value of this product can be raised further. This product is suitable for WtE plants as it has a low alkali content, due to that it has been washed. Page 55/89

56 Figure 28 Utilisation of solid fuel The solid fraction can also be separated further to recycle more fractions. This allows for the flexibility to optimise recycling and fuel production. Further separation will be outside the REnescience battery limit Recyclables The REnescience process generates several recyclable fractions. Figure 29 Recyclable streams from the REnescience process The metals recovered from the REnescience process are of a high quality for reuse, because the metal parts in the MSW are recovered after the biological process. This means that organic content is removed from eg cans. Furthermore, the metallic materials are not oxidised in contrast to metal recycled after combustion of MSW. The inert material consists mainly of sand, soil, small stones and small glass pieces. The material is washed and very suitable for road filling etc. The plastic fraction can be recovered from the solid fraction by applying appropriate sorting techniques. Investigations are on-going to identify the quality demand for the recovered plastic fraction to be actually recycled to the market. Furthermore work has been initiated to improve the quality of the plastic fraction. (The mentioned investigations and work are part of the EUDP project in progress). Page 56/89

57 Use of output from the REnescience process The output products described in section can be utilised in various ways. This section describes the expected quality of the products and the most common use of these. The output products from the REnescience process are intermediate products in the energy and resource chain. The products can either be utilised on site or sold/exported to companies specialised in utilising or further treatment of these products Study of plant concepts In this section some examples of total waste paths are set up. The section describes three cases, but several other cases could be set up depending on the economic, locational and legislational contexts the REnescience process is to be operating in. As described in section , the products produced by the REnescience process can be utilised in various ways. To illustrate how a total waste utilisation solution could look like, two total concepts are set up and total power (and heat) production is calculated. The different process plants in these concepts can be located at one site or at more than one site with different owners. The concepts below therefore do not necessarily illustrate one business concept, but rather the total value chain of the MSW, and the efficiencies of them Basic concept The basic concept shows the process concept REnescience right now is testing at the demonstration plant at Amagerforbrænding I/S. This concept for use of the REnescience products is very basic and well proven by REnescience. Process water Biogas and gas engine Unsorted MSW 86 GJ 10 t 3.2 t 26 GJ W-t-E plant 46 GJ Inert mat. Metals Figure 30 Basic concept The basic concept is interesting if the WtE gate fee is relatively low. The REnescience plant could typically be located at an existing WtE plant and use the plant s MSW receiving facilities. By more than halving the quantity of MSW to combustion, a REnescience add-on could up to double an Page 57/89

58 existing WtE plants MSW reception capacity. The REnescience plant could thereby replace a new WtE plant in an area with a growing capacity demand High power production concept The high power production concept utilises the REnescience process capability of splitting up the none-degradable MSW in a mainly plastic fraction with high energy content and a fraction with lower energy content. Figure 31 High power production concept The mainly plastic fraction can eg be used for co-combustion at coal-fired power plants, and thereby replaces coal, or it can be used in the cement production industry. The mainly plastic fraction can be baled, stored and sold in a market for RDF/SRF. This means a higher price for the solid fuel and a better utilisation of the energy content of the fuel. The high power production concept is very interesting in markets with high gate fees for WtE plants, as the quantity for treatment at WtE plant is reduced by 90%. Furthermore, this concept is very interesting in markets transferring from depositing waste to eg building WtE plants, as the number of needed WtE plants are reduced significantly. Furthermore, this concept is interesting in areas with no district heating system as more of the energy content in the MSW is converted into electricity. These two concepts are only examples of possible combinations of technologies. REnescience will be happy to assist in evaluation of other technology combinations relevant to our customers Green waste processing concept The green waste processing concept is relevant in areas where source separation of household waste is already established or obligatory. The four major benefits of implementing the REnescience process in a waste system with source separation are: The REnescience process works well even on green fractions containing much non-organic material. No minimum quality of the source separation is required. Page 58/89

59 There is no reject prior to the process, where much organic material typically is lost. The reject after the REnescience process is very limited and does only contain non-degradable products. The biogas production process on the bioliquid is very robust with no mechanical challenges. The biogas production from the green waste is increased. It is very difficult to set up a standard or typical green waste composition, as it heavily depends on the source sorting instructions and the quality of the source sorting. In this case, the composition shown on Figure 32 is used. Figure 32 Composition of source separated green waste (Riber et. al. 2009) Using the waste composition shown on Figure 32, the output from the REnescience process is calculated. The expected in- and outputs are shown on Figure 33: Bio-Liquid m: 13 t/h V: 1052 Nm 3 /h DM: 25 % Biogas CH4 LHV: 35,8 MJ/Nm 3 m: 10 t/h LHV: Unsorted MSW 5,3 MJ/kg Water Heat Power Enzymes Water: 3 m 3 /h Heat: 3 GJ/h Solid fuel Recyclables m: 1,0 t/h LHV: Metals: Inert mat.: 13 MJ/kg 0,1 t/h 0,2 t/h Figure 33: In- and outputs from the REnescience process with source separated household waste as feedstock If all the solid fuel is treated at a WtE plant, and the bioliquid is used for biogas production followed by gas engines for power production, the total concept and energy outputs will be as shown in Figure 34: Page 59/89

60 Process water Biogas and gas engine Unsorted MSW 53 GJ 10 t 1.0 t 18 GJ W-t-E plant 26 GJ Inert mat. Metals Figure 34 Green waste processing concept In the green waste processing concept, the green waste is converted into high value energy and concurrently, the nutrients eg phosphors can be recycled back to the agricultural use via the remaining liquid from the biogas process. This combines the benefits of composting (nutrient recycle) and the benefit of combustion (energy production) in one system without the respective disadvantages of the two systems. Page 60/89

61 5.10 WP7 Evaluation of the liquefaction concept, environmental assessment, feasibility etc Life cycle assessment Within the initial phase of the project, the structure of the Life cycle assessment (LCA) model was defined and a first version established in the modelling tool EASEWASTE. The aim was to present the REnescience process in a modelling tool and account for important mass and energy flows. Based on the above activities, the LCA model was continuously updated and improved with respect to process data. Meanwhile, system boundaries and assessment methodologies have been evaluated and coordinated with respect to state-of-the-art practices. A significant effort was put into developing a detailed description of energy flows and potential substitution of energy as a consequence of using the REnescience process on waste. The final results of the LCA work is described under WP 13 and technical papers listed in the publication list Initial feasibility The purpose of WP7 was to set up an early evaluation of the REnescience concept to decide whether to continue or to stop the work. This first evaluation was reported and delivered to Energinet.dk as: PSO Project no REnescience WP7, Preliminary Estimates on Liquefaction Process October The final evaluation of the process is described under WP13. Page 61/89

62 5.11 WP13 Environmental evaluation and feasibility study of the concepts As a part of the REnescience PSO project a mass and energy balance was designed to support technical, environmental and financial feasibility studies of the REnescience technology. The following section gives a brief overview of the model and the products where is has been used Calculation model for the REnescience technology The purpose of the model is to give a cohesive overview of the REnescience process, as well as being capable of predicting the treatment of a waste stream based on the composition of the waste Modelling the waste The description of the incoming MSW is based on the 48 fractions presented in the work by Riber et al. (2009). Based on this composition, an aggregate waste composition is constructed consisting of: Metals Plastic Glass Textiles Digestible organics Other combustibles Other non-combustibles In the first versions of the model the digestible organics were treated as a single fraction. In the current version it has, however, been found to be advantageous to divide the digestible organics into several constituents, such as cellulose, fat, starch etc. The model is then capable of predicting the products from the REnescience process based on a waste composition Modelling the process The REnescience process is modelled as a continuous process consisting of several steps. Each step has been modelled taking into account: Biochemical conversion Phase changes Heat demand Cooling demand Mass split of the different components. The conversion and mass splits have been estimated based on lab scale, bench scale and pilot scale experiments giving a model capable of capturing the real process. The model is furthermore constructed in such a manner that any new knowledge/findings can be incorporated in the model. Since a large part of the waste is water, typically 40 50%, and a substantial amount of water is added in the process, the IAPWS97 steam table (Wagner and Kretzschmar, 2008) has been incorporated in the model to give a good description of the state variables in the process, in particular the enthalpy of the waste stream. Physical properties of the other components in the waste have been found in a multitude of references. Page 62/89

63 Model output The output from the model is (based on a given MSW composition): Heat and power consumption in the process Water consumption in the process Quantity and composition of the outgoing streams In Figure 35, the overall mass and energy balance based on the composition in Riber et al. (2009) can be seen. Bio-Liquid mm: t/h DM: 21 20,8 % Biogas CH4 V: 934 Nm 3 /h LHV: 36 MJ/Nm 3 m: 2.4 t/h RDF LHV: 18 MJ/kg Unsorted MSW mm: 0,8 t/h 831 m: kg/h t/h Solid fuel LHV: 7 MJ/kg 7,1 LHV: #REF! 8,6 MJ/kg Water Heat Power Metals: 0.3 t/h m 266 Enzymes Recyclables minert mat.: 0,9 926 t/h Water: 8 t/h Heat: 5 GJ/h Figure 35. The overall mass and energy balance of the REnescience process Conclusions and future work. A model of the REnescience process has been constructed. The model is capable of predicting the conversion of waste based on a composition. As a part of the model the demand for energy and consumables is also predicted. The model is used as a central part in making feasibility studies for existing and potential customers. Since the solid separation and washing is not fully optimised yet, this part of the model will still need further improvement as more experience is gathered through laboratory and pilot plant tests Life cycle assessment The main activities and outcomes generated by DTU in WP13 can be summarised as the following: A working prototype LCA model of the REnescience waste refinery process Definition of relevant implementation scenarios and collection of associated inventory data Modelling and interpretation of LCA modelling results Publication of a scientific paper in a peer-reviewed journal Participation in international conferences, including publication of conference proceedings. In Tonini & Astrup (2011), a life cycle assessment and energy balance of a pilot-scale version of the REnescience process for the enzymatic treatment of MSW is presented. The process generated a liquid (liquefied organic materials and paper) and a solid fraction (non-degradable materials) from the initial waste. A number of scenarios for the energy utilisation of the two outputs were assessed. Co-combustion in existing power plants and utilisation of the liquid fraction for biogas production were concluded to be the most favourable options with respect to their environmental impacts (particularly global warming) and energy performance. The optimisation of the energy and Page 63/89

64 environmental performance of the waste refinery was mainly associated with the opportunity to decrease energy and enzyme consumption Methodology The functional unit of the life LCA was "treatment of one tonne (1000 kg) of Danish residual municipal solid (wet) waste". The assessment considered the waste as a zero-burden boundary (ie the waste as such was not assumed to carry any environmental impacts). Downstream utilisation of recovered heat/electricity and recyclable materials were credited the system by system expansion into the energy and industrial sectors (saved production of energy and virgin materials). The boundary of the system was set at the treatment facility gate (incinerator and waste refinery) and included downstream disposal of incineration ashes and recycling of materials. Following common practices in LCA studies, all environmental impacts (resource consumption, emissions to air, soil and water) related to the transportation and treatment (until final disposal) of the liquid and solid fractions, recyclables, bottom and fly ashes were included for a time horizon of 100 years. The assessment was carried out according to the LCA method EDIP 1997 following the principles of consequential LCA, ie focusing on the consequences of a decision (in this case implementation of the REnescience technology). This means for example that energy generated by the waste system was assumed to substitute energy production at the plants which actually respond to the change, rather than substituting average energy production. The following impact categories were included in the assessment: Global Warming (GW), Acidification (AC), Nutrient Enrichment (NE), Ecotoxicity in water chronic (ETwc), Human Toxicity via water (HTw), Human Toxicity via soil (HTs), Human Toxicity via air (HTa). The life cycle assessment included two sets of scenarios: 1) various approaches for energy utilisation of outputs from the waste refinery, and 2) various configurations of the surrounding energy system reflecting a range of assumptions regarding downstream energy substitution. The scenarios are presented and further discussed in Tonini & Astrup (2011). Input data about the REnescience process for use in the LCA model were obtained based on experimental data from the tests, from the calculation model described previously, and if needed from literature. A range of assumptions were necessary to carry out the LCA; these are described in more detail in Tonini & Astrup (2011) Conclusions The results of the LCA demonstrated that enzymatic refining of the waste with utilisation of the products for energy recovery can represent a valuable alternative to incineration from an environmental point of view. This is particularly the case if the downstream energy options for exploiting the solid and liquid fractions are co-combustion and anaerobic digestion for biogas production. The principal savings of the waste refinery process were related to higher metal and energy recovery (particularly with respect to electricity) compared to that of incineration. Improvement in the environmental as well as energy performance of the waste refinery itself was primarily related to the optimisation of energy and enzymes consumption. The LCA investigation reported here are under further development as part of the ongoing EUDP project. Page 64/89

65 Feasibility A preliminary feasibility study was drawn up in a first report, submitted in The emphasis at that time was on utilising the solid fraction as co-firing fuel in coal-fired power plants. In the meantime, it has become obvious that this possibility is not viable on a longer term due to the costs involved in transforming the solid fraction into a useful fuel for a coalpowder-fired power plant boiler and also due to the on-going phasing out of coal-firing in Denmark. We have therefore chosen instead to look at the more realistic option to provide fuel for less demanding applications such as cement kilns, where the firing equipment is more suited for directly applying the solid fraction from RSC without need for excessive costly fuel preparation. This section draws up a preliminary economic study on the application of the REnescience liquefaction concept, taking the present outlook into account. The envisaged possible scenarios for utilisation of the output stream from the RSC core process is depicted in Figure 36. Figure 36 Value chain for the REnescience liquefaction process We have in this study decided to focus on the combination of producing waste derived fuel (RDF) and utilising the bioliquid for producing biogas and subsequently renewable power and heat. The reason for this choice is that market prices for the products are well described as well as the subsidies available and taxation are known. Page 65/89

66 1) The liquid fraction is used for biogas production either for local power/heat production or as supplier to the NG net. 2) The solid combustible fraction is co-fired in conjunction with an industrial process such as an cement kiln or in an advanced gasification power plants. The economic calculations are made for a full-scale liquefaction plant which is considered to have a capacity of (10 t/h). As there are a lot of variables with a wide span, a number of sensitivity analyses have been made and on basis of these, a discussion and conclusion on the concept of waste liquefaction have been made Economy Methodology and presumptions A spread sheet model of RSC core plant together with the necessary additional process equipment enabling production of goods recognised in the market associated with a known market value have been developed. The additional equipment needed to complement the RSC core is a RDF preparation facility, a biogas plant and a gas engine. The economic control volume containing the entire value chain is shown in Figure 37. Figure 37 Value chain for the REnescience process It has been selected to calculate the treatment price for the net waste amount treated by RSC that is the amount of waste taken in minus the amount of waste output, which has to be treated at a conventional waste incineration plant. By doing so, we are circumventing the delicate problem of figuring out the financial aspects in a CHP waste incineration plant. DONG Energy is experienced in establishing waste incineration plants and CAPEX estimates on building costs, and other auxiliaries are for that reason based on a 20 tonnes per hour waste incineration plant, which was raised in Jönköping, Sweden. Experience from Inbicon A/S and other process plants are correspondingly used. Operational and design data solely for the enzymatic Page 66/89

67 liquefaction is based on the experience from operation of the pilot plant at Amagerforbrænding and the lab-scale tests. The calculation is made as a tool in the continued system optimisation in matters of process and economy, here in particular to shed light on parameter connections and sensitivities. The calculation is structured based on a plant with a reference capacity/size of 10 tonnes of waste per hour. "The Waste refinery" produces as mentioned before a bio-slurry, a solid combustible fraction containing plastics, metals and glass. Metals and glass are accounted for at the market price The combustible part is assumed to substitute fossil fuel such as petcoke at a cement kiln or similar firing application without need for shredding into fine particles. Prices for such fuel are conservatively estimated at 0 DKK/tonne according to what is heard unofficially in the market. Generally, Danish prices including tax are applied as these real prices are what prospective plant owners will look after in their decision whether to establish a RSC plant or other another solution. In the basis scenario, the following presumptions shown in Table 6 are used. Table 6 Presumptions used in the feasibility study Year of evaluation 2011 Time of commissioning 2014 Inflation 2% Cost of capital 6% Economic lifespan (year) 20 Annual operating period (h) 8000 Power and heating prices are according to forecast from the Danish energy agency. CAPEX and OPEX have been estimated from experiences from the pilot plant and discussions with potential suppliers of the main process equipment. No waste related tax is assumed for the processes within the economic control volume. This is in accordance with current practice at similar plants producing biogas and power from source segregated waste. Elaborate studies have been carried out to forecast the enzyme cost over the lifespan of a plant. The resulting prognosis shows an initial annual decrease in expected enzyme cost as seen in the past 2-3 years, followed by a gradually flattening out of the costs due to the decreasing interest in developing the technology as the enzyme costs becomes less important. The forecast tendency is depicted in Figure 38. Page 67/89

68 Enzyme cost forecast 400% 350% 300% 250% 200% 150% 100% Experienced development 50% 0% Figure 38 Forecasted specific enzyme cost Treatment cost in the basis scenario The results of the calculation for the basis scenario are shown in Figure 39. Figure 39 Basis calculation: Averaged treatment costs over operating period Page 68/89

69 The calculated net treatment in the basis scenario is significantly lower than for the majority of existing CHP waste incineration plant in Denmark. The cost structure also shows the crucial factors for an economic optimisation of the REnescience technology which are: Reduction of CAPEX Reduction of expenditure of enzymes Reduction of biogas related costs, mainly the deposition costs for the digestate Sensitivity analysis The idea of the sensitivity analysis is to show the impact of the treatment cost if some of the basic presumptions change: Size of plant, to show how economically feasible it will be to scale down the plant size Impact, if CAPEX and cost of capital show to be higher than anticipated As projected enzyme costs are very uncertainty of nature, treatment cost are calculated at a higher level of enzyme cost Uncertain level of subsidies for biogas based production, scenarios are calculated with elevated biogas subsidies. Figure 40 shows the results of the sensitivity analysis on these parameters. Figure 40 Sensitivity calculation for selected alternative scenarios Page 69/89

70 It can be noted that in a worst scenario, the resulting treatment cost can be 160% of the treatment cost in the basis scenario and still be in the same range as for the present Combined Heat and Power (CPH) waste incineration plants in Denmark. It is significant to notice that the calculations are made for Danish conditions. Looking through Europe quite different circumstances appear; first of all, there is not enough treatment capacity to follow the new and severe legislation put into force. Secondly, the available treatment plants are not nearly as energy efficient as Danish treatment plants. This adds even broader perspectives to the liquefaction process. Page 70/89

71 5.12 WP15 Gasification and poly-generation WP15.1 Poly-generation. Identification of the optimum layout of an integrated gasoline/power plant The aim of the study was to show how the Polygeneration concept can help to solve key challenges in the future Danish energy system regarding balancing of wind, cost efficient security of supply, "green" district heating and "green" transportation fuels. The Polygeneration concept is based on a TIGAS (Topsøe Integrated Gasoline Synthesis) process where biomass is gasified and the synthesis gas is converted into either gasoline ("max gasoline" concept) or power and heat ("max power" concept) depending on the value of the products. Due to the high fluctuations in power, price the optimal product may change on an hour-to-hour basis. Cooling of process streams and off-gases are also used to generate steam and subsequently power and heat. The breakdown of products [MJ/s] is shown below for two different 135MWth polygeneration concepts; one optimised for "max gasoline" and one where it is possible to use the syngas in a new power block for "max power" production during periods with high power prices. The backpressure mode is with max district heating production (steam condensing at ~1 bar) and condensing mode is with max power production (steam condensing at ~0.05 bar). Optimised for "Max gasoline" Optimised for "Max power" A "Max power" concept can also be achieved by combustion of syngas in an existing power plant during periods with high power prices. However, based on the power price forecast up to 2025 (wind development similar to a "50% wind power" scenario in 2025) and expected received gasoline price of 6DKK/l, the analysis finds that it is not profitable to invest in a "max power" concept for two reasons: The number of hours with sufficiently high power prices to switch from gasoline is too low It is not profitable to displace fossil fuel in an existing power plant with syngas from a polygeneration plant. Thus, the most economically profitable concept is "max gasoline" where mainly gasoline and heat are produced. A 135MWth plant using Danish woodchips can produce traditional octane 95 gasoline at approximately 5DKK/l and supply green district heating for 80DKK/GJ, with an IRR of 10%. Page 71/89

72 It is, however, expected that the gasoline based on biomass is more valuable than 5DKK/l, and as illustrated in Figure 41 an interesting return on investment can be obtained. Figure 41 Return on investment depending on the gasoline price To summarise, the Polygeneration concept shows a promising way to provide low cost green fuel for transportation and green district heating with both high energy and exergy utilisation of the biomass. The key challenges to mature the polygeneration concept is development of high temperature dust filter and tar reformer. A new tar reformer concept could potentially change the overall heat and mass balance, and thus the output of district heating and power. For the full report, see attached document no A. Page 72/89

73 WP15.2 Re-fuel with biomass by a gasification process Objective of the study The overarching objective of the study has been to identify whether eg SKV3 or another unit can partly be re-fueled with biomass by a gasification process. This should be seen as an alternative to the already suggested conversion to 100% wood pellets needing mills for pulverisation. Furthermore, it has been considered whether the gasification process can use either the plastic fraction or the dried bioliquid fraction from the REnescience process in a combination with wood. Various gasifier solutions have been studied, and various suppliers as well as external expertise have been contacted. Compared to the solution with wood pellets, the gasification process has several potential advantages. Investment in DeNOx and bag filter might be avoided and low cost fuels can be used. The concept offers flexibility, as it might be feasible to only replace say 1/3 of the natural gas consumption. These qualitative advantages have been quantified in a preliminary financial evaluation Available feedstock Biomass for a project at SKV3 with a view to the available gasifier technology from the above mentioned suppliers only woody biomass can come into consideration. The local possibilities identified are woodchip and willow. According to Statistics Denmark and Hededanmark, 150,000 tonnes of wood chip are being produced every year in the south region of Denmark. It is estimated that the production can be doubled with a resulting potential of 300,000 tonnes per year in total. From the energy report about energy from willow, Energipilerapport, which is published in collaboration with Landbrug & Fødevarer, it is stated that 100,000 tonnes of woodchips can be produced from willow in the surrounding of SKV3. Woodchips from willow seem to be somewhat more expensive compared to woodchips produced from other sources. But new harvesting methods are under development where the moisture content will be reduced to 25% thereby making woodchips from willow a more profitable option. If the domestic woodchip production will be insufficient, it is estimated to be possible to import woodchips from the baltic countries where only 70% of the potential 40 million m 3 /year is utilised. Page 73/89

74 Plant design Concept The conceptual idea is a partial replacement of natural gas at SKV3 allowing the plant to operate nearly continuously over the year at technical minimum load, still supplying a substantial part of the district heating consumption. Continuous operation of the plant is vital for allowing it to support grid stability in a volatile power market due to the development in wind power. This calls for a firing capacity of the gasifier of approximately 200MW which can be divided on two units, if required. A quick overview of the main technical implications of adding such a gasifier installation to the existing plant scheme is presented in the following figure: Wood chips unloading Quay crane and load point from truck, including screen and magnetic separator. Wood chips storage Fuel silo with a capacity of 25,000m 3, corresponding to one week s full load. Wood chips drying Atmospheric chip dryer, equipped with steam tapping at approx. 6 bar condensate returning to the process. Discharged water is led to a new wastewater treatment plant. Gasifier Atmospheric circulating fluidised bed gasifier 2 x 100MW t Gas cooler Gas cooling, C to C Equipped with feed water parallel with the main boiler, steam returns to the boiler start-up vessel. Hot gas filter Ceramic hot gas filter, C removes alkali chloride, heavy metals and dust, to be purged with N 2. Main boiler The main boiler is equipped with two new burners, located at the centre of the front and rear walls at burner level 20. Page 74/89

75 A few comments are given to the technical implications of each of the mentioned operations are given in the subsequent sections Fuel drying In order to make the process more efficient, it is necessary to dry the woodchips to obtain a moisture content of 20% before gasification. It means that approx. 33% of the moisture content in the wood chips must be removed. Steam, flue gas, hot air or hot water can be used as drying media. Drying systems can be divided into two main types: Atmospheric and pressurised. The most common type is an atmospheric drum dryer where the drum is heated in a closed cycle. Heated air and/or flue gas is blown into the drum and evaporates the water from the wood chips and transports it into open air through one or more stacks. An alternative to the drum dryer is the belt dryer where heated air and/or flue gas is blown below the belt and through the wood and into the open air. Emission of water vapour can be avoided if the water vapour is condensed and afterwards purified before the waste water is discharged. As a heating source, a closed cycle with outlet steam from steam existing tapping at the Intermediate Pressure (IP) turbine (7bar/427 C) is assumed, where the condensate returns to the main condensate system Gasifier The gasifier is an atmospheric CFB (Circulating Fluidised Bed) where the bed material and the fuel are fluidised and circulated by separating the solid particles by means of a cyclone which returns the particles to the reactor. Depending on fuel characteristics, especially alkali chloride content, the bed temperature can vary from C. Thus, the fuel s tendency to agglomerate in the bed is minimised/eliminated. The gasifier consists of reactor, cyclone, air blower, air preheater, system for bed material, bottom ash system, start-up burner and connecting duct work. All components are manufactured in carbon steel, and the plant installations, which are in contact with hot gas, are protected by brickwork where the first layer is insulating, and the other layers are resistant to physical and chemical erosion. Typical main data per gasifier selected from experience from existing plants: Syngas composition: CO 2 : %-vol.-wet H 2 O: N 2 : CO: H 2 : 8.61 C x H y : 5.42 (hereof assumed, 5.12 % CH 4 and 0.3 %C 3 H 8 ) COS: 0.00 H 2 S: 0.01 On top of that there is 15g/Nm 3 (dry) tar in the gas (calculated as benzene C 6 H 6 in the boiler calculations) Page 75/89

76 Syngas is delivered to the boiler at 424 C Before this, the gas is cooled during production of steam: 9.4MW Internal consumption for the process is estimated to be 600kW for a gasifier including a dryer with a fired capacity of 100MW based on dried fuel (20% moisture). Gas filtration The temperature of the product gas must be below 450 C to ensure condensation of the biomass related alkali metals, released during the gasification process. To prevent condensation of tar the product gas needs to be kept warm during the cleaning process. Keeping the temperature above 350 C will reduce the risk of tar condensation. This temperature limit can be expected lowered by making a more specific investigation of the actual tar dew point. Investigations of the tar dew point related Fluid Bed Biomass Gasifiers have shown: ECN (Wood, gasification temp.: 750 C C, variations in residence time and moisture content): - Highest tar dew point measured: around 300 C LT-CFB (Digested manure) - Measured tar dew point: around 150 C C) This means that temperature window of particle cleaning is given to 350 C to 450 C (safe mode). But further investigations of the actual tar dew point related to this gasification process are likely to expand this window of operation to around 250 C C Heat balances The main data stated in section is used to perform a consequence study for SKV3 for the four operational set point, Technical minimum and maximum load in combined heat and power operation and during solely power production. An impression of the results of these calculations can be acquired from Figure 42. Page 76/89

77 Figure 42 Mass and heat balance for the four cases investigated at SKV Market survey Gasification of solid fuels such as biomass and waste is a developing technology, and on a global basis there are various processes and demonstration plants. Gasification of oil, lignite and peat is based on well-proven technologies in scales of up to several hundreds of MW. Meanwhile, the challenges of gasification of biomass are far greater than those of gasification of fossil fuels. There are several demonstration plants for gasification of biomass based on different technologies. Most of the demonstration plants have limited thermal load. Technologies that are based on thermal loads ranging from a few KWs to approx. 25MW are not considered relevant to SKV3. This is because upscaling to a 100MW commercial plant is considered too uncertain and risky. The following are realised projects based on processes that may be of interest to SKV3 in terms of fuel, technology and size: Ruien PS/Belgium Foster Wheeler 80MW/biomass Lahti Energia/Finland Foster Wheeler 50MW/biomass, SRW 4 Lahti Energia/Finland (LathiStreams 5 ) Metso Power 2x80MW/SRW AmerCentral/Holland Envirotherm 83MW/biomass Supplier contact Based on the above argumentation it was chosen to contact the following companies, in order to understand the technical maturity of large-scale biomass gasification and filtration. Discussions with these companies also enabled us to create realistic CAPEX estimations: Metso (Finland) FWC (Finland) 4 Solid Recovered Waste 5 Page 77/89

78 Envirotherm (Germany) Andritz-Carbona (Finland) Uhde (Germany). None of the companies were prepared to offer full process guarantee for the entire scope, especially not for the gas filtration part, which they still consider as an immature technology. Hence, if such a project has to be executed, it has to be based on some kind of joint development project, where the owner has to accept limited process guaranties CAPEX estimate and overall financial considerations First estimates on CAPEX and OPEX have been made for the entire installations necessary for establishing 2 x 100MW firing capacity. The total cost of establishing the concept partly based on received budget offers on main equipment has been estimated to DKK1.2 Billion +/- 30%. An initial simulation of the potential operating pattern of the plant indicates a possible IRR of 16%- 20% for this investment Conclusion It has been shown through the project activities that: the project seems technically feasible, though process guarantees will be hard to obtain due to immature character of especially the gas filtration technique (immature technology) a viable business case exists, provided that existing subsidy schemes on biogas from gasifiers exist during the lifespan of the installations. DONG Energy is considering to pursue this option in a subsequent, more detailed study, as this could increase the use of domestic fuels. Page 78/89

79 5.13 WP9 Testing of the liquefied straw on existing entrained flow gasifiers This work package was cancelled as agreed on in the change letter of May WP10 Design and construction of a gasoline demonstration plant This work package was cancelled as agreed on in the change letter of May WP11 Demonstration of a flexible gasoline production based on entrained flow gasifier This work package was cancelled as agreed on in the change letter of May Page 79/89

80 6. WP14 Project management DONG Energy has been the coordinator of the REnescience project and therefore responsible for the project management. In general, the project partners have succeeded in developing very promising technology, a technology that has already developed way further than the PSO application level. The project has also been characterised by great flexibility from both project partners and our sponsor to continuously learn from the knowledge gained in the project to adjust the direction, cut out parts that have been evaluated not to be feasible and put in other alternatives that turned out to be very interesting. In that way the project description has never stopped developing. This has, of course, generated some extra work in the project management and for our sponsor, but also led to a final product, meant as a technology development, which is highly relevant to the today market - and wanted - by key market interests. Page 80/89

81 7. Financial Project Number 7335 Title (automatic) Budget Financing (including feed-in tarif ) Total (DDKx1000) Other (DDKx1000) Internal (DDKx1000) PSO funding (DDKx1000) Contract sum , , ,0 Supplementary grant , ,0 Supplementary grant 2 - Total , , ,0 Accumulated costs (sum of periods) Residual sum / residual commitment REnescience A flexible and integrated energy system based on gasification of liquefied biomass and waste , , ,5 (12 493,2) - (13 498,8) 1 005,5 Net expenses realised during the periods (sum of periods) Total Other (DDKx1000) (DDKx1000) Internal (DDKx1000) PSO funding (DDKx1000) Before ,5-919,5 940,0 1. half ,7-785,6 805,1 2. half , , ,6 1. half , , ,4 2. half , , ,9 1. half , , ,2 2. half , , ,4 1. half , , ,8 2. half , , ,0 1. half half Accumulated costs , , ,5 Page 81/89

82 Total PSO funding PSO share Dong Energy , ,3 47,2% Amagerforbrænding 9 308, ,0 50,0% Novozymes 25,2 12,6 50,0% Haldor Topsøe 3 700, ,1 47,8% KU 4 749, ,0 92,7% DTU 1 500, ,0 100,0% Total , ,0 53,1% Page 82/89

83 8. Conclusion During the four years that this project has been running, the main drivers in both the energy system and the waste treatment systems have changed toward extended flexibility as well as sustainability and resource protection. This project fits very well into this changed view, and the developed technologies can become important players in the future energy and resource landscape, nationally and internationally. Flexibility has been the keyword in execution of the project. Even though the initial purpose of the project was very visionary and focused on flexible energy and fuel production, it was possible to redefine the purpose when it during the first analysis and tests became visible that a fossil-free solution was possible and even closer to becoming a commercial possibility. The initial focus was on liquefying MSW and producing the bioliquid suitable for gasification in pressurised gasification process (as a minor feedstock together with coal) with a following use of the synthesis gas in a flexible gasoline/power production. The changed setup focuses on using the bioliquid for biogas production, and the decision secured the feasibility and the relevance of the project but cut up the original concept in two separate technology concepts. One concept regarding the energy production from household waste, and one concept regarding the use of syngas from biomass gasification for a flexible liquid fuel and/or power production depending on the market demand. Both projects are still very relevant but the connection between them turned out not to be viable. The waste liquefaction technology has during this project matured from being a technology scanned in lab-scale indicating good potentiality to being a technology that has been tested in a continuous process for a long period and in pilot-scale showing feasibility in several settings. An early construction of the first pilot-scale batch reactor was mandatory in the progress of getting a continuous process. The tests made on the reactor gave very good input for the design and later the installation of a continuous run pilot plant. The pilot plant has now been in operation for nearly two years and this has given a unique opportunity to test the produced downstream fractions for different purposes in larger scale. The setup of a commercial scale waste liquefaction plant will depend very much on the local waste and energy infrastructure. The kind of waste source segregation systems used will for instance to a high degree affect the quality and split of the bioliquid and the solid fraction. And an establishment of a gas motor would not be necessary if an introduction of the biogas to a nearby natural gas system is possible. A scenario in an urban district will differ from a scenario in a country district. In the latter, a solution with bio-gasification together with manure with a following utilisation of the biogas residue on farmland will be probable. In an urban scenario, on the other hand, a bio-gasification of the bio-liquid together with sewage sludge at a waste water treatment plant would be a likely setup. Here an utilisation of the residue on farmland seems not as apparent. Page 83/89

84 Calculating the net treatment cost in a basis scenario shows somewhat lower costs than for the majority of the existing CHP waste incineration plants in Denmark. The results of the LCA demonstrated that enzymatic refining of the waste with utilisation of the products for energy recovery can represent a valuable alternative to incineration from both an energy and environmental point of view. This is particularly the case if the downstream energy options for exploiting the solid and liquid fractions are co-combustion and anaerobic digestion for biogas production. The principal savings of the waste refinery process were related to higher metal and energy recovery (particularly with respect to electricity) compared to that of incineration. Improvement in the environmental as well as energy performance of the waste refinery itself was primarily related to the optimisation of energy and enzymes consumption. For both financial and environmental purposes there should be a strong and constant focus on reducing enzyme consumption. Regarding financial feasibility focus should also be on reducing CAPEX as well as reduction of biogas related costs, mainly the deposit costs for the digestate. The feasibility evaluations are made in a general Danish context. Looking through Europe quite different circumstances appear; first of all, there is not enough treatment capacity to follow the new and severe legislation put into force. Secondly, the available treatment plants are not nearly as energy efficient as Danish treatment plants. This adds even broader perspectives to the liquefaction process. The findings in the project have made most of the partners initiate another R&D project Funded by the Danish EUDP fund scaling up the technology to commercial size and comparing the treatment costs of the REnescience technology with those of the proposed new incineration facility at Amagerforbrænding. DONG Energy has chosen to emphasise the development of the technology even more intensive and has formed a subsidiary company, REnescience A/S, with the purpose of commercialising the waste liquefaction concept. Page 84/89

85 9. References Literature Riber, C., Petersen, C., & Christensen, T. H. (2009), Chemical composition of material fractions in Danish household waste, Waste Management 29, pp Wagner, W. & Kretzschmar, H.-A. (2008), International Steam Tables Properties of Water and Steam Based on the Industrial Formulation IAPWS-IF97, 2 nd ed., Springer. Electronic references Inbicon A/S. 2011, LahtiStreams IP. 2011, ReTec A/S, 2011, Page 85/89

86 10. Enclosures Polygeneration report Page 86/89