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Life Cycle Assessment: A Tool for Evaluating and Comparing Different Treatment Options for Plastic Wastes

Life Cycle Assessment: A Tool for Evaluating and Comparing Different Treatment Options for Plastic Wastes. G. Dodbiba 1 , K.Takahashi 1 , T. Furuyama 2 , J. Sadaki 1 , T. Kamo 3 , and T. Fujita 1. 1. Department of Geosystem Engineering, The University of Tokyo, Japan

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Life Cycle Assessment: A Tool for Evaluating and Comparing Different Treatment Options for Plastic Wastes

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  1. Life Cycle Assessment: A Tool for Evaluating and Comparing Different Treatment Options for Plastic Wastes G. Dodbiba1, K.Takahashi 1, T. Furuyama 2, J. Sadaki 1, T. Kamo 3, and T. Fujita 1 1. Department of Geosystem Engineering, The University of Tokyo, Japan 2. Department of Earth Resource Engineering, Kyushu University, Japan 3. National Institute of Advance Industrial Science and Technology, Japan

  2. Outline 1. LCA Methodology (ISO 14040) 2. LCA of Plastic Wastes from Discarded TV Sets 3. Concluding Remarks

  3. Outline 1. LCA Methodology (ISO 14040) 2. LCA of Plastic Wastes from Discarded TV Sets 3. Concluding Remarks

  4. Scope of LCA … to evaluate or compare the life cycle of “products”

  5. Life-Cycle Stages and Boundaries (Source:EPA, 1993)

  6. Methodology:Life Cycle Assessment, (ISO 14040) Definition of products; Choice of alternatives; Definition of system boundary; Data collection; Theoretical calculation; Evaluation Reporting the results; Propose improvement; Phase 1: Phase 2: Phase 3: Phase 4: (Source:Consoli et.al., 1993)

  7. Aim of Study … to evaluate and compare different recycling options for plastic wastesfrom old TV sets in context ofLCA

  8. Compositions of a TV Set (weight %) (Source:O. Murakami, Mitsubishi Elec. ADVANCE, pp. 6-9, 2001).

  9. Conventional Recycling System for TV sets Problem: How to recycle plastic wastes? Source:Association for Home Electrical Appliances of Japan http://www.aeha.or.jp/assessment/en/english_flame.html

  10. Objective … to compare two different recycling options for plastic wastesfrom old TV setsin context ofLCA. Option 1: Incineration of plastics for energy recovery (also known as thermal recycling) Option 2: Sorting plastics for mechanical recycling (also know as material recycling)

  11. Outline 1. LCA Methodology (ISO 14040) 2. LCA of Plastic Wastes from Discarded TV Sets 3. Concluding Remarks

  12. Methodology:Life Cycle Assessment, (ISO 14040) Definition of products; Choice of alternatives; Definition of system boundary; Phase 1: (Source:Consoli et.al., 1993)

  13. Phase 1 of LCA: Goal Definition and Scope a. Subject of the study are plastic wastes from old TV sets (display: 25”, weight = 30 kg), which contain: b. Functional unit: is defined as 1.8 million TV sets per year, over a period of 10 years. • PS (6.0 wt%, i.e. 1.80 kg), • PVC (3.5 wt%, i.e. 1.05 kg), • PE (1.0 wt%, i.e. 0.30 kg).

  14. Life-cycle of plastics for TV sets Special cases: (1). Energy recovery, i.e.c = 0 %; (2). Mechanical recycling, i.e.c = 100 %andr = 67 %

  15. Methodology:Life Cycle Assessment, (ISO 14040) Data collection; Theoretical calculation; Phase 2: (Source:Consoli et.al., 1993)

  16. Phase 2 of LCA: Inventory analysis a) Data collection The data of the processes, namely: were from the LCA database of the Japan Environmental Management Association for Industry (JEMAI). • production of PS, • production of PVC, • production of PE, • production of electricity, • production of a TV set,

  17. Phase 2 of LCA: Inventory analysis a) Data collection Option 1:Incineration of 1 kg plastic material Energy generated: PS – 9,604 kcal/kg PVC – 4,300 kcal/kg PE – 11,140 kcal/kg Emission: 2,640 g CO2 /kg Source:K. Krekeler et al., Kunstsoffe, 55/10, pp. 758, 1965 Source:Ministry of Environment of Japan, Guidelines, 2004

  18. Plastics Density, [kg/m3] PVC 1400 Option 2:Separation of plastic wastes prior to mechanical recycling 1st Step 2nd Step PS 1050 PE 960

  19. Phase 2 of LCA: Inventory analysis a) Data collection Option 2: Separation of plastic wastes (by combining triboelectric separation and air tabling) Energy: 0. 74 kWh/kg Triboelectric separator 0.04 kWh/kg Air table 0.66 kWh/kg Size reduction 0.02 kWh/kg Sieving 0.02 kWh/kg Recovery of products: 67 % Grade of products: > 95 %

  20. the matrix A represents the flow of products and materials g is the vector of the environmental interventions the vector frepresents a special process where the functional unit is an output the matrix B represents the flow of environmental loads Steps to be followed in theoretical calculation: • Calculate the inverse of matrix of A(i.e.A-1) • Calculate the inventory vector g Phase 2 of LCA: Inventory analysis b) Theoretical calculations

  21. Methodology:Life Cycle Assessment, (ISO 14040) Evaluation Phase 3: (Source:Consoli et.al., 1993)

  22. Phase 3 of LCA: Impact assessment The categories of the environmental impacts: • a) Abiotic resources: ADP (in kg Sb eq.) • b) Global warming: GWP (in kg CO2 eq.)

  23. Phase 3 of LCA: Impact assessment a) Depletion of Abiotic Resources, (ADP)

  24. 1.6 x Phase 3 of LCA: Impact assessment a) Depletion of Abiotic Resources, (ADP)

  25. Phase 3 of LCA: Impact assessment b) Global Warming Potential (GWP)

  26. 1.4 x Phase 3 of LCA: Impact assessment b) Global Warming Potential (GWP)

  27. Methodology:Life Cycle Assessment, (ISO 14040) Reporting the results; Propose improvement; Phase 4: (Source:Consoli et.al., 1993)

  28. 1.5 x Phase 4 of LCA: Main ResultsEnvironmental Impact

  29. Outline 1. LCA Methodology (ISO 14040) 2. LCA of Plastic Wastes from Discarded TV Sets 3. Concluding Remarks

  30. Concluding Remarks • The energy recovery (option 1) and the mechanical recycling (option 2) of plastic wastes from the discarded TV sets were compared in the context of LCA. • The energy recovery is an treatment option that generated more energy due to the incineration of plastic wastes. Nevertheless, this option also uses more resources and emits a larger quantity of greenhouse gases. • The separation of plastics for mechanical recycling is more effective alternative, because it consumes fewer energy and resources, as well as has a lower environmental impact on global warming.

  31. Conventional Recycling System for TV sets Source: Matsushita Eco Technology Center (METEC) Available from internet: http://panasonic.co.jp/eco/en/metec/tv/material2-1.html

  32. Three alternativesare being considered when dealing with plastic wastes: • energy recovery (also known as thermal recycling), i.e. direct incineration of plastic wastes for energy recovery • mechanical recycling (also known as material recycling),i.e. the method by which plastic wastes are recycled into new resources without affecting the basic structure of the material; • feedstock recycling (also known as chemical recycling), i.e. the technique that break down polymers into their constituent monomers, which in turn can be used again in refineries or petrochemical and chemical production.

  33. Required Purity of Sorted Plastics for Reuse (courtesy of KINKI KOGYO Co. Ltd., Japan) Reuse of plastics in circulating system as low grade plastics : > 95.0 % Reuse of plastics in circulating system as virgin plastics : > 99.5 % Reuse of plastics for agricultural, horticultural industry, etc. : > 99.0 % Use of plastics as oxidant in blast furnaces : < 1.0 % (PVC impurity)

  34. Life Cycle Assessment Framework (Source:LCA, ISO 14040)

  35. Bond’s Method: Size-reduction Wi = 13.81 kWh/t DP = 2.63 mm DF = 5.00 mm

  36. Production of 1 kg PS (Source: JEMAI-LCA On-line Database)

  37. Production of 1 kg PVC (Source: JEMAI-LCA On-line Database)

  38. Production of 1 kg PE (Source: JEMAI-LCA On-line Database)

  39. Production of 1 kWh Electricity (Source: JEMAI-LCA On-line Database)

  40. Production of a TV set (Sources: a. JEMAI-LCA On-line Database; b. Murakami, 2001)

  41. Matrix B of Environmental interventions

  42. Demand vector, f

  43. Technological Matrix, A

  44. Structure of LCA model

  45. After choosing the FINAL DEMAND of the product, the simplest UNIT PROCESS can be written as follows: INPUT (product flow) x (scaling parameter) = (final demand) OUTPUT (environmental flow) x (scaling parameter) = (environmental intervention) Ref.: Leontief, 1970 (Winner of Nobel Prize in 1973)

  46. Input ( - ) Output ( + ) Technological parameters Emission from the process Inventory data Process Technology matrix; A Final demand vector; f Process 1……………Process n ?? Environmental intervention matrix; B Inventory; g

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