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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 2. Department of Earth Resource Engineering, Kyushu University, Japan 3. National Institute of Advance Industrial Science and Technology, Japan Slide 2 Outline 1. LCA Methodology (ISO 14040) 2. LCA of Plastic Wastes from Discarded TV Sets 3. Concluding Remarks Slide 3 1. LCA Methodology (ISO 14040) 2. LCA of Plastic Wastes from Discarded TV Sets 3. Concluding Remarks Outline Slide 4 Scope of LCA to evaluate or compare the life cycle of products Slide 5 Life-Cycle Stages and Boundaries Source ( Source: EPA, 1993) Slide 6 Definition of products; Choice of alternatives; Definition of system boundary; Data collection; Theoretical calculation; Evaluation Reporting the results; Propose improvement; Methodology: Life Cycle Assessment, (ISO 14040)Phase 1: Phase 2: Phase 3: Phase 4: Source ( Source: Consoli et.al., 1993) Slide 7 Aim of Study to evaluate and compare different recycling options plastic wastes old TV sets for plastic wastes from old TV sets LCA in context of LCA Slide 8 Compositions of a TV Set (weight %) Source (Source: O. Murakami, Mitsubishi Elec. ADVANCE, pp. 6-9, 2001). Slide 9 Source: Source: Association for Home Electrical Appliances of Japan http://www.aeha.or.jp/assessment/en/english_flame.html Conventional Recycling System for TV sets Problem: How to recycle plastic wastes? Slide 10 Objective plastic wastes old TV sets LCA to compare two different recycling options for plastic wastes from old TV sets in context of LCA. Option 1: Incineration energy recovery Option 1: Incineration of plastics for energy recovery (also known as thermal recycling) Option 2: Sorting mechanical recycling Option 2: Sorting plastics for mechanical recycling (also know as material recycling) Slide 11 1. LCA Methodology (ISO 14040) 2. LCA of Plastic Wastes from Discarded TV Sets 3. Concluding Remarks Outline Slide 12 Definition of products; Choice of alternatives; Definition of system boundary;Phase 1: Source ( Source: Consoli et.al., 1993) Methodology: Life Cycle Assessment, (ISO 14040) Slide 13 a. Subject of the study are plastic wastes from old TV sets (display: 25, weight = 30 kg), which contain: 1.8 million 10 years. b. Functional unit: is defined as 1.8 million TV sets per year, over a period of 10 years. Phase 1 of LCA Phase 1 of LCA: Goal Definition and Scope 1. PS 1. PS (6.0 wt%, i.e. 1.80 kg), 2. PVC 2. PVC (3.5 wt%, i.e. 1.05 kg), 3. PE 3. PE (1.0 wt%, i.e. 0.30 kg). Slide 14 Special cases: c = 0 %; (1). Energy recovery, i.e. c = 0 %; c = 100 % r = 67 % (2). Mechanical recycling, i.e. c = 100 % and r = 67 % Life-cycle of plastics for TV sets Slide 15 Data collection; Theoretical calculation;Phase 2: Source ( Source: Consoli et.al., 1993) Methodology: Life Cycle Assessment, (ISO 14040) Slide 16 The data of the processes, namely: JEMAI were from the LCA database of the Japan Environmental Management Association for Industry (JEMAI). Phase 2 of LCA: Inventory analysis a) Data collection 1. production of PS, 2. production of PVC, 3. production of PE, 4. production of electricity, 5. production of a TV set, Slide 17 Option 1: 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 CO 2 /kg Source: K. Krekeler et al., Kunstsoffe, 55/10, pp. 758, 1965 Phase 2 of LCA: Inventory analysis a) Data collection Source: Ministry of Environment of Japan, Guidelines, 2004 Slide 18 PS1050 PE960 PlasticsDensity, [kg/m 3 ] PVC 1400 1 st Step 2 nd Step Option 2 Option 2: Separation of plastic wastes prior to mechanical recycling Slide 19 Option 2 Option 2: Separation of plastic wastes (by combining triboelectric separation and air tabling) Energy:0. 74 kWh/kg Triboelectric separator0.04 kWh/kg Air table0.66 kWh/kg Size reduction0.02 kWh/kg Sieving0.02 kWh/kg Recovery of products: 67 % Grade of products:> 95 % Phase 2 of LCA: Inventory analysis a) Data collection Slide 20 Steps to be followed in theoretical calculation: 1.A -1 1.Calculate the inverse of matrix of A (i.e. A -1 ) 2.g 2.Calculate the inventory vector g Phase 2 of LCA: Inventory analysis b) Theoretical calculations the matrix A represents the flow of products and materials g is the vector of the environmental interventions the matrix B represents the flow of environmental loads the vector f represents a special process where the functional unit is an output Slide 21 EvaluationPhase 3: Source ( Source: Consoli et.al., 1993) Methodology: Life Cycle Assessment, (ISO 14040) Slide 22 The categories of the environmental impacts: ADP a) Abiotic resources:ADP (in kg Sb eq.) GWP b) Global warming:GWP (in kg CO 2 eq.) Phase 3 of LCA Phase 3 of LCA: Impact assessment Slide 23 Phase 3 of LCA: Impact assessment a) Depletion of Abiotic Resources, (ADP) a) Depletion of Abiotic Resources, (ADP) Slide 24 Phase 3 of LCA: Impact assessment a) Depletion of Abiotic Resources, (ADP) a) Depletion of Abiotic Resources, (ADP) 1.6 x Slide 25 Phase 3 of LCA: Impact assessment b) Global Warming Potential (GWP) b) Global Warming Potential (GWP) Slide 26 Phase 3 of LCA: Impact assessment b) Global Warming Potential (GWP) b) Global Warming Potential (GWP) 1.4 x Slide 27 Reporting the results; Propose improvement;Phase 4: Source ( Source: Consoli et.al., 1993) Methodology: Life Cycle Assessment, (ISO 14040) Slide 28 Phase 4 of LCA: Main Results Environmental Impact 1.5 x Slide 29 Outline 1. LCA Methodology (ISO 14040) 2. LCA of Plastic Wastes from Discarded TV Sets 3. Concluding Remarks Slide 30 Concluding Remarks energy recoveryoption 1mechanical recyclingoption 2plastic wastes LCA 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. energy recovery 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. mechanical recycling 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. Slide 31 Slide 32 Slide 33 Slide 34 Source: Matsushita Eco Technology Center (METEC) Available from internet: http://panasonic.co.jp/eco/en/metec/tv/material2-1.html Conventional Recycling System for TV sets Slide 35 Three alternatives are being considered when dealing with plastic wastes: 1. 1.energy recovery (also known as thermal recycling), i.e. direct incineration of plastic wastes for energy recovery 2. 2.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; 3. 3.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. Slide 36 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) Slide 37 Life Cycle Assessment Framework Source (Source: LCA, ISO 14040) Slide 38 Bonds Method: Size-reduction W i = 13.81 kWh/t D P = 2.63 mm D F = 5.00 mm Slide 39 Production of 1 kg PS (Source: JEMAI-LCA On-line Database) Slide 40 Production of 1 kg PVC (Source: JEMAI-LCA On-line Database) Slide 41 Production of 1 kg PE (Source: JEMAI-LCA On-line Database) Slide 42 Production of 1 kWh Electricity (Source: JEMAI-LCA On-line Database) Slide 43 Production of a TV set (Sources: a. JEMAI-LCA On-line Database; b. Murakami, 2001) Slide 44 Matrix B of Environmental interventions Slide 45 Demand vector, f Slide 46 Technological Matrix, A Slide 47 Slide 48 Structure of LCA model Slide 49 INPUT (product flow) x (scaling parameter) = (final demand) FINAL DEMAND UNIT PROCESS After choosing the FINAL DEMAND of the product, the simplest UNIT PROCESS can be written as follows:OUTPUT (environmental flow) x (scaling parameter) = (environmental intervention) Ref.: Leontief, 1970 (Winner of Nobel Prize in 1973) Slide 50 Technology matrix;A Final demand vector;f Environmental intervention matrix;B Inventory;g ? Process Input ( - ) Output ( + ) Inventory data Process 1 Process n Technological parameters Emission from the process Slide 51 Linear programming a Product flow, a s Scaling parameter, s f Demand, f b Environmental flow, b g Environmental intervention, g (Heijung et.al, 2002) Slide 52 Equations can be written in terms of matrixes Slide 53 Technology matrix Final demand vector Scaling vector Intervention matrix Inventory vector Slide 54 Inverse matrix of technology matrix A Final demand vector Scaling vector Environmental intervention matrix Inventory vector Solution: Linear programming / Matrix manipulation (Heijung et.al, 2002) Slide 55 The outcome of the inventory analysis was the vector g, which is a list of the quantities g i of pollutants released to the environment and the amount of energy and materials consumed during the life-cycle of plastics for TVs production (Matrix B), i.e.: for i = 1, 2, , n LCI Results g vector Slide 56 The categories of the environmental problems: a)ADP a)Resource depletion/Abiotic depletion ADP (in kg Sb eq.) b)GWP b)Global warming GWP (in kg CO 2 eq.) c)AP c)Acidification, AP (in kg SO 2 eq./kg) d)POCP d)Photo-oxidant formation, POCP (in kg C 2 H 4 eq./kg) e)EP e)Eutrophication, EP (in kg PO 4 eq./kg) f)HTP f)Human toxicity, HTP (in kg 1,4-DCB eq./kg) Phase 3 of LCA Phase 3 of LCA: Impact assessment Slide 57 How to calculate the environmental impact? The impact indicator I j of each category was calculated after all the environmental loads g i within a category were characterized and aggregated using the following equations, g Results of LCI, g vector Slide 58 Characterization factors, k i Characterization factors, k i Source: Handbook of LCA, 2002 Slide 59 Normalization q indicates the number of the environmental impact categories. The indicator I j of each environmental impact category is divided by a reference value known as normalization factor w j Slide 60 World (1995) ADP 1.57 10 11 kg (Sb eq.) yr -1 GWP 3.86 10 13 kg (CO 2 eq.) yr -1 AP 2.99 10 11 kg (SO 2 eq.) yr -1 POCP 4.55 10 10 kg (C 2 H 4 eq.) yr -1 EP 1.29 10 11 kg (PO 4 eq.) yr -1 HTP 4.98 10 13 kg (1,4-DCB eq.) yr -1 Weighting factors, k i Source: Handbook of LCA, 2002 Slide 61 Phase 3 of LCA: Impact assessment a) Energy Depletion (ED) 3 x 1.4 x Slide 62 energy recovery mechanical recycling Comparing energy recovery (option 1) with mechanical recycling (option 2) Environmental IndicatorsOption 1, (Energy recovery) Option 2, (Mechanical recycling) Energy balance (ED), in [kcal] -158,808,456,261-186,049,047,033 Abiotic depletion potential (ADP), in [kg Sb. eq.] 1,143,091698,156 Global warming potential (GWP), in [kg CO 2 eq.] 452,329,521334,977,313 Slide 63 An Estimate for the Environmental Burden (EEB) Slide 64 3.4.3. Sensitivity Analysis - perturbation method, g (Matrix of Environmental Load, g) where: Slide 65 Sensitivity Analysis Scenarios for: a. saving resources (ADP), and b. reducing the greenhouse gas emission (GWP) Slide 66 3.4.4. Strategy to reduce the environmental burden 1. 1.Collect as many TV sets as possible 2.PS PVC or PE 2.Use PS instead of PVC or PE for production of TV sets (i.e. possibly excluding PVC) in turn: a. The efficiency of the separation process will be improved reducing the ADP indicator, b. The emission of CH 4 and CO 2 will be reduced (i.e. GWP)