Solid biofuels from torrefied biomass Production of Solid Sustainable Energy Carriers from Biomass by Means of Torrefaction The SECTOR project Wolfgang Stelte, Ph.D. Center for Biomass and Biorefinery Danish Technological Institute DTI
Danish Technological Institute -DTI Private, self-owned and not-for-profit institution Development and dissemination of research- and technologicallybased knowledge for the Danish and international business sectors
Center for Biomass & Biorefinery Biomass logistics and storage : Safety, cost reduction, supply chain modeling and optimization Characterization: Chemical analysis, heating value, combustion properties, ash content, impurities Pre-treatment: Mechanical, thermal, enzymatic pre-treatment of biomass High value side streams: Materials, nutrients, food, feed, fertilizer Liquid, solid, gaseous biofuels Industry consulting R&D Projects with industry and universities
Pellet related activities at DTI Pelletizing process: Laboratory and pilot scale facilities Lab scale: Single pellet press - Parameter screening and optimization, friction and quality test (100 g material) Bench scale: Kahl press, flat die (50 kg/h) Pilot and production scale facilities: Andritz presses (250-2000 kg/h)
Pellet related activities at DTI Storage and handling and safety of pellets Research activities and consulting in the following areas: Monitoring of critical parameters: Risk evaluation, hazard reduction and fire prevention Self heating, oxygen depletion and off-gassing during transport & storage Safety in silos and during shipping, ATEX, dust Prevention
Pellet related activities at DTI Standardization and quality analysis Offering commercial analysis Wide range of standard methods (EN/ISO) Development of new test methods Biomass Analysis: Ash, heavy metals, sulfur, chlorine, C, H, N, Ash melting and slagging, etc. Pellet quality: Mechanical durability, heating value, density, etc. Consulting pellet producers: Standardization and certification
SECTOR Project Production of Solid Sustainable Energy Carriers from Biomass by Means of Torrefaction SECTOR Collaborative project financed by European Commission Project start: 01.01.2012 Duration: 42 months Total budget: 10 Mio. Euro Participants: 21 from 9 EU-countries Coordinator: DBFZ
SECTOR SECTOR Project Project
Pellets from torrefied biomass Advantages of torrefaction and pelletization Torrefaction is a mild roasting of biomass in an inert atmosphere Removal of water and volatiles from biomass Increased heating value Increased C/O ratio: better combustion / fuel properties Fibers are converted into a brittle material Easy to grind (coal mill) Dry product with hydrophobic characteristics Biomass with coal like properties Pelletization Increase density and reduce dust formation Lowering transportation and handling costs Standardized size and automated feeding
Pellets from torrefied biomass Possible problems when pelletizing torrefied biomass High friction in press channel High energy uptake of pellet mill up to 150 kwh/t (usually 50-60 kwh/t for wood pellets) Heat generation in pellet mill (risk of fire / dust explosion) Lower capacity More wear on the pellet mill parts Pellet quality Durability Self heating Density Hydrophobicity Storage of torrefied pellets Dust Issues are closely linked to - Biomass feedstock - Torrefaction parameters - Pelletization parameters - Can be different case by case Requires knowledge and further studies
Pellets from torrefied biomass Single pellet press tool: Fast and only few grams of material needed Set-up allows variation of: Temperature, pressure, particle size, moisture, and additive addition Determination of: Compression energy, friction and quality analysis of pellets Earlier tests have shown correlation between friction and energy consumption of industrial scale pellet press
Pellets from torrefied biomass Example: Pelletization of torrefied pine tree Friction increase when pelletizing torrefied pine tree Increase of friction for torrefied biomass Pellet mill: Energy requirements increase Capacity gets lower More heat development in press
Pellets from torrefied biomass What can we do to improve the pelletizing properties? Increase moisture content Increase die temperature Add a lubricant to reduce friction Additives Change press channel dimensions Torrefaction parameters Temperature Reaction time We have looked on a few of them Some examples
Pellets from torrefied biomass Example: Pelletization of torrefied pine tree Increase of die temperature 125-190 C Friction is reduced by 50% No effect on the untreated pine tree
Pellets from torrefied biomass Example: Pelletization of torrefied pine tree 5 % water addition Friction is reduced by 50%
Pellets from torrefied biomass Example: Pelletization of torrefied pine tree 2% rape seed oil Friction is reduced by 70 % But Negative impact on pellet strength
Pellets from torrefied biomass Parametric study which parameters are the important ones Design of experiments - Torrefaction degree expressed as mass yield (90.5% - 71.1%) - Temperature 250 to 300 C - Moisture content (0 to 10%) - Die temperature (125-180 C) - Particle size( small / big)
Pellets from torrefied biomass Parametric study which parameters are the important ones Key results: - Main parameters affecting friction and pellet durability are: torrefaction degree, moisture content and die temperature - High torrefaction degree increases friction and decreases pellet strength - Water addition and increasing temperature counteracts this effect Mathematical modeling of the interaction between the parameters and their dependency is in progress and will be published soon
Pellets from torrefied biomass Successful Pilot and production scale trials - Partners in SECTOR project have successfully produced several tons of torrefied pellets - Large scale production facilities in SECTOR project - Energy center of The Netherlands (ECN) - National Renewable Energy Center, Spain (CENER) - Umeå University & Swedish Agricultural University (SLU), Sweden - Topell, The Netherlands - Feedstock: Pine, spruce, poplar, willow, forest residues, straw, - Material are used in logistics, storage and combustion trials right now Successful demonstration of the technology
Briquetting of torrefied biomass Spruce 240 C 260 C 280 C
Briquetting of torrefied biomass Feeding tank Conditioning of raw material : Water addition Briquetting press: outlet Cooling conveyor Production trials with Industry partner C.F. Nielsen Briquette press manufacturer
Briquetting of torrefied biomass Results from production trials Raw material Spruce (fresh) 240 C 260 C 280 C Density (raw material) kg/m3 153 181 157 162 Moisture % 13,4 5,2 4,3 4,8 Particle size min mm 1x1 0,1x0,1 0,1x0,1 0,1x0,1 Particle size max mm 10x5 5x2 5x2 5x2 Process Power consumption A 70 85 85 80 Die Temperature C 160 165 200 205 Strokes per min 1/min 269 269 269 269 Strokes number n 13 9 16 17 Capacity (measured) kg/h 600 660 600 600 Product Diameter mm 59 59 60 59,5 Length mm 155 115 162 159 Volume cm3 424 314 450 442 Weight g 446 318 456 444 Density (briquette) kg/m3 1053 1012 1013 1005
Briquetting of torrefied biomass Continuous briquetting of torrefied spruce without stoppages Briquette quality is good but slightly decreasing for higher torrefaction temperatures Water addition can improve the briquette strength, there is an optimum moisture content further tests required to confirm Unit Density is around 1000 kg/m 3 but can most likely be improved by adjusting die diameter and length and by adding additives. Latest developments shows densities up to 1300 kg/m 3 for small tests. Briquette surface is porous, flake like structures Latest developments shows improvements Process needs further optimization to obtain a sealed surface of the briquette Best results when briquettes remain under heat and pressure for longer time Baking of the briquette Friction increases with degree of torrefaction (Temperature increase), however Capacity and Power consumption of press remains stable
Market situation for torrefied fuels Barriers for commercialization of torrefied pellets Technology is ready but, manufacturers and buyers are risk averse to new technologies Producers are willing to implement torrefaction technology and produce torrefied biomass, but before investing in a full size commercial plant they need long term off take contracts from bankable customers Buyers are not un-willing to buy, but first they need to prove that promises concerning torrefied biomass use are met, including quality and volume guarantees, and on operational issues. Classic Chicken and Egg problem One has to make the first move
Thank you for your attention! For more information please contact: Wolfgang Stelte Consultant, Ph.D. Biomass & Biorefinery Danish Technological Institute Energy and Climate Mobile: +45 7220 1072 wst@teknologisk.dk Gregersensvej 2 DK- 2630 Taastrup Denmark Tel. +45 7220 2000 Fax +45 7220 2019 www.teknologisk.dk
"The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement n 282826."