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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.

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Presentation on theme: "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."— Presentation transcript:

1 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

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

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

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

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

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)

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

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

9 Source: Source: Association for Home Electrical Appliances of Japan Conventional Recycling System for TV sets Problem: How to recycle plastic wastes?

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)

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

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)

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 kg), 2. PVC 2. PVC (3.5 wt%, i.e kg), 3. PE 3. PE (1.0 wt%, i.e kg).

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

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

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,

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

18 PS1050 PE960 PlasticsDensity, [kg/m 3 ] PVC st Step 2 nd Step Option 2 Option 2: Separation of plastic wastes prior to mechanical recycling

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

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

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

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

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

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

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

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

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

28 Phase 4 of LCA: Main Results Environmental Impact 1.5 x

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

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.

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34 Source: Matsushita Eco Technology Center (METEC) Available from internet: Conventional Recycling System for TV sets

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.

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)

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

38 Bonds Method: Size-reduction W i = kWh/t D P = 2.63 mm D F = 5.00 mm

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

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

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

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

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

44 Matrix B of Environmental interventions

45 Demand vector, f

46 Technological Matrix, A

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48 Structure of LCA model

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)

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

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)

52 Equations can be written in terms of matrixes

53 Technology matrix Final demand vector Scaling vector Intervention matrix Inventory vector

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)

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

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

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

58 Characterization factors, k i Characterization factors, k i Source: Handbook of LCA, 2002

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

60 World (1995) ADP kg (Sb eq.) yr -1 GWP kg (CO 2 eq.) yr -1 AP kg (SO 2 eq.) yr -1 POCP kg (C 2 H 4 eq.) yr -1 EP kg (PO 4 eq.) yr -1 HTP kg (1,4-DCB eq.) yr -1 Weighting factors, k i Source: Handbook of LCA, 2002

61 Phase 3 of LCA: Impact assessment a) Energy Depletion (ED) 3 x 1.4 x

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, ,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

63 An Estimate for the Environmental Burden (EEB)

64 Sensitivity Analysis - perturbation method, g (Matrix of Environmental Load, g) where:

65 Sensitivity Analysis Scenarios for: a. saving resources (ADP), and b. reducing the greenhouse gas emission (GWP)

66 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)


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