How To Understand The Environmental Impacts Of A Plastic Bottle

Transcription

1 COUPLING LIFE CYCLE ASSESSMENT AND PROCESS SIMULATION TO EVALUATE THE ENVIRONMENTAL IMPACTS OF PLASTICS WASTE MANAGEMENT: APPLICATION TO PET BOTTLES RECOVERY LCA SRCR June 2014, Falmouth Amélie Botton 1, Hai AnBillaudot², Leslie Jacquemin 3, Alan Jean-Marie 2 Process simulation Recycling 1 Laboratoire de Génie des Procédés Plasmas et Traitements de Surface, Chimie ParisTech, Paris, France 2 Altran RESEARCH, Vélizy-Villacoublay, France 3 Altran RESEARCH, Blagnac, France Contact: [email protected]

2 1. Introduction Context Altran Research, the in-house research department of Altran, will provide Altran with new assets for new product development. Transverse and multidisciplinary research Technology transfer Methodology transfer New Product Development Innovative services New markets between established industries Numerous stakeholders with different needs APS Advanced Products & Solutions Develop models & simulation tools for new product development. Investigate state-of-the-art technologies. Demonstrate feasibility in complex context. SEA Sustainability Engineering & Assessment Develop knowledge, models, processes, and simulation tools to assess sustainability of products and services. 2/14

3 1. Introduction Context Context: Rarefaction of the fossil resources ; pollutions engendered by plastics to landfill. Problem: How to make sure that the existing or future recycling solutions are sustainable? Case of PET bottles: >>Amatureenoughsubjecttomakeaninterestingcase study for the development of a modeling and optimisation methodology of the environmental impacts by simulation process. 3/14

4 1. Introduction Context What is the considered system? PET is a thermoplastic which can be recycled or valuated by thermal conversion, thermochemical conversion, chemical conversion, mechanical recycling, etc. Simplified system:wehaveconsidered2pathwaysand5processes 4/14

5 2. Methodology - Life cycle assessment Midpoint indicators are considered to assess the sustainability of each pathway. LCI Midpoint indicators NO x CO 2 CH 4 C 2 H 4 Naphtha LPG Coal Natural gas CML2 (2000) Abiotic depletion (kg eq of Sb) Acidification (kg eq of SO 2 ) Selected Eutrophication (kg eq of PO 3-4 ) indicators Global warming/gwp 100 (kg eq of CO 2 ) Ozone layer depletion (kg eq of CFC-11) Human toxicity (kg eq of 1,4-DB) Fresh water aquatic ecotoxicity (kg eq of 1,4-DB) Marine aquatic (kg eq of 1,4-DB) Terrestrial ecotoxicity (kg eq of 1,4-DB) Photochemical oxidation (kg eq of C 2 H 4 ) Midpoint indicators are deduced from the inventory by CML 2 Baseline 2000 method. We need to get accurate data for the Life Cycle Inventory (LCI). Relevant indicators are selected from LCI. 5/14

6 2. Methodology - Life cycle assessment Our method differs from classical Life Cycle Inventories (LCI) based on the Ecoinvent data. The classical assessment method : the REFERENCE Life cycle analysis using the Ecoinvent database. Considers total conversion and products with high level of purity. No or few information on the process conditions. Our method : the SIMULATED process Life cycle analysis coupled with a process simulation tool for each pathway. Purification steps and conversion rates are taken into account. Heat and matter are recovered and considered as avoided products in the system. For both : the functional unit is the production of 1kg of PET converted. 6/14

7 2. Methodology - Process simulation Example of process simulation PET recycled by glycolysis Purity of outgoing products, purification technique used, temperature, pressure Energy efficiency: 65% BHET EG PET DMT Type of reactor, operating conditions, products, conversion rates Energy source: french energy mix Hot steam produced : coal, natural gas Purity of outgoing products, purification techniques used, temperature, pressure Thermodynamic model: NRTL/SRK Software: Aspen Hysys 7.2 7/14

8 3. Results and Discussions The classical approach (based on the Ecoinvent data) underestimates the environmental impacts but generally, in a life cycle analysis, a difference is significant from 20 points. Example with the case of hydrocracking 100% 80% 60% Témoin REFERENCE 40% 20% Simulation SIMULATED 0% Abiotic depletion Acidification Eutrophication Global warming Relative gap between 3 and31 31% Working hypotheses Parameters REFERENCE SIMULATED Conversion 99,3% 80 % Wastes treatment 0 kg 0,25 kg 8/14

9 3. Results and Discussions Comparison between both methods After calculating the impacts: Same substance but different quantity between each method Causes : Take into account of Technology Readiness Level (TRL) in REFERENCE may explain the differences of results between these two methods. Impacts between each process : Importance of solvent used and more energy consumption for the chemical processes. 100% REFERENCE method 100% SIMULATED method 80% 80% 60% 60% 40% 40% 20% 20% 0% Abiotic depletion Acidification Eutrophication Global warming 0% Abiotic depletion Acidification Eutrophication Global warming 9/14

10 3. Results and Discussions Main results of the study Comparison of pathways Impacts of thermochemical processes < impacts of chemical processes Causes: take into account of matter and energy recovery Matter recovery = avoided production of raw material Energy recovery = avoided of energy inputs Comparison of process pathway (case of thermochemical) Impacts of pyrolysis < impacts of incineration < impacts of hydrocracking Causes: Hydrocracking : low energy recovery in comparison with pyrolysis and incineration + high impact from hydrogen production (95% from fossil resource) Incineration : Good level of energy recovery but, significant CO 2 emission Pyrolysis : High level of energy recovery and process in inert atmosphere (few greenhouse gases emissions) 10/14

11 4. Modeling and Simulation of results Research of a supply chain optimum Context 1mattertorecover:thePET 5 processes studied : glycolysis, methanolysis, hydrocracking, pyrolysis, incineration Modeling of system 5 decision variables: X 1 = glycolysis, X 2 = methanolysis, X 3 = hydrocracking, X 4 = pyrolysis, X 5 = incineration 3 response criteria: Y 1 =acidification,y 2 =eutrophication,y 3 =globalwarmingpotential Working hypotheses Flowofmatterarefixed matterbalanceconstantforthe5processes Response criteria vary linearly with the feedstock Modeling form : Y n = f(x m ) 11/14

12 4. Modeling and Simulation of results Approachby«completeblockdesign» Simulation method Example of X m combination minimizing the impacts for SIMULATED method X 1 X 2 X 3 X 4 X ,1 0,1 0,8 0 0,1 0,1 0,1 0,7 Global warming potential Eutrophication Acidification Example of X m combination minimizing the impacts for REFERENCE method X 1 X 2 X 3 X 4 X ,1 0,1 0,8 0,1 0,1 0,1 0,1 0,6 12/14

13 4. Conclusion and perspective Conclusion Coupling process simulation and life cycle assessment is an efficient approach method for environmental assessment. Process simulation is a relatively simple method. This work has been realized with only six parameters: the type of chemical reaction, the conversion rate, the temperature, the pressure, the purification technique, the purity level of the products. Process simulation is particular interesting when data are not available : incomplete or imprecise. Most of all, process simulation makes possible to take into account real conversion rates and the need of separation steps to get required purity. These purification steps drastically increase the environmental impacts. Our method by process simulation is complementary to the industrial data collection to build a decision making tool. Perspective For further studies, we want to: integrate economic indicators, study the sensibility of results, validate the method on a more complex case study (composite material for example). 13/14

14 Thank for your attention!