1、Environmental Life Cycle Assessment,An LCA Introduction and an investigation of Biodiesel LCAs Joyce Smith Cooper Mechanical Engineering University of Washington cooperjsu.washington.edu,Material processing,Product manufacturing,Product use, maintenance, upgrade,recovery,disposal,Other life cycles,A
2、ssessment Questions: Why? What? Who? Where? How? When? With what environmental implications? At what cost? What opportunities exist for partnerships, elimination of toxics, material recovery, ?,Material extraction,Defining the Product Life Cycle,A coffee makers life cycle,From Pr Consultants, “The E
3、co-indicator99: A damage oriented method for Life Cycle Impact Assessment, Manual for Designers,“ http:/www.pre.nl/eco-indicator99/index.html,Life Cycle Assessment,LCA is a technique for assessing the environmental aspects and potential impacts associated with a product by: compiling an inventory of
4、 relevant inputs and outputs of a product system evaluating the potential environmental impacts associated with those inputs and outputs interpreting the results of the inventory and impact analyses in relation to the objective of the study.,Goal and Scope Definition,Inventory Assessment,Interpretat
5、ion,Impact Assessment,Direct Applications Product development and improvement Strategic planning Public policy making Marketing,From ISO14040-1997, Environmental management- Life cycle assessment- Principles and framework,Goal and Scope of the study,The goal of a LCA describes the intended applicati
6、on (what is being assessed?), the reasons for carrying out the study, the intended audience (to whom the results of the study are intended to be communicated) The scope of the LCA considers System function Included materials and processes Type of impact assessment,From ISO14040-1997, Environmental m
7、anagement- Life cycle assessment- Principles and framework,Different ways to provide the same function,Hold coffee Plastic cup, polystyrene cup, ceramic cup, china cup, thermos, Maintain a tidy haircut Plastic comb, metal comb, razor Mowing your lawn Power mower, reel mower, a goat Protecting a surf
8、ace from corrosion Painting, anodizing, make from plastic .,From Wenzel, H., M. Hauschild, L. Alting, 2000, Environmental Assessment of Products: volume 1: Methodology, tools, and case studies in product development, Chapman Hall Publishers, New York.,Functional Unit,ISO14040-1997: “a measure of the
9、 performance of the functional outputs of the product system” Includes: A magnitude A duration A level of quality,System Boundaries,ISO14040-1997: What materials/ equipment will be included How will this be determined What phases of the life cycle will be included The reality often by material weigh
10、t (% of product) facilities, equipment, and infrastructure are often neglected,The Life Cycle Inventory,Create a process flow diagram/ mass balance for the life cycle. Identify The product flows between unit processes Material and energy use and waste that comes from or goes to the environment,The U
11、nit Process,Unit Process,Outputs Product Co-Products= open loop reuse/ recycle Waste (fugitive or to treatment: air, water, solid),Inputs Raw or Intermediate Materials Energy,For each unit process, identify inputs, outputs, and recovery as follows:,Closed Loop Reuse/ Recycle,Process Data Sources,Mea
12、surements LCI databases: USDatabase Project, Boustead, SimaPro, GaBi, DEAM, BUWAL, APME (plastics data) Literature data: LCA reports Engineering References: Encyclopedia of Chemical Technology, Kirk-Othmer, Ulman, etc. Journal and conference papers National laboratory research reports Emission facto
13、rs (AP-42, etc.) EPA sector notebooks Computation/ Parametric Models (for example, GREET),“Gasoline combustion in industrial equipment” Data from the US Database Project at www.nrel.gov/lci/ user name of lcilci.org and a password of lci,“Electricity Production” Data from the US Database Project at w
14、ww.nrel.gov/lci/ user name of lcilci.org and a password of lci,Impact Assessment,Impact assessment looks at how inventory flows (cause) contribute to impacts (effect) Impact assessment can include Classification inventory flows are placed in impact categories Characterization the contribution of eac
15、h inventory flow is estimated for each impact of interest Normalization the contribution of the product to each impact at the global, national, regional, or local level is assessed Valuation/ Weighting subjective preferences are used to prioritize impact categories and impacts,Impact Assessment,Clas
16、sification Inventory materials are categorized as: Abundant or rare, Hazards, Regulated materials, Recyclable materials, Materials that contribute to global warming, acidification.,Classification by Material Abundance,Materials can be classified as those in infinite supply: Ar, Br, Ca, Cl, Kr, Mg, N
17、, Na, Ne, O, Rn, Si, Xe ample supply: Al (Ga), C, Fe, H, K, S, Ti adequate supply: I, Li, P, Rb, Sr potentially limited supply: Co, Cr, Mo(Rh), Hi, Pb (As, Bi), Pt (Ir, Os, Pb Rh, Ru), Zr (Hf) potentially highly limited supply: Ag, Au, Cu (Se, Te), He, Hg, Sn, Zn, (Cd, Ge, In, Tl) (lists by-product
18、metals in parentheses after their reservoir parent),From Graedel, T., B. Allenby, Design for Environment, Prentice Hall (1996),Classification,Qualitative process of categorizing inventory flows,Classification,AcidificationEutrophication,Classification: Global Warming,-(CF2)4CH(OH)- (CF3)2CFOCH3 (CF3
19、)2CHOCH3 (CF3)2CHOCHF2 (CF3)2CHOH (CF3)CH2OH C2F6 CARBON DIOXIDE CARBON TETRAFLUORIDE C-C3F6 C-C4F8 CF3 CF2CH2OH CH3OCH3 FIC-1311 HCFE-235DA2 HFC-125 HFC-134 HFC-134A HFC-143 HFC-143A HFC-152 HFC-152A,HFE-338MCF2 HFE-347MCC3 HFE-347-MCF2 HFE-356MCF3 HFE-356MEC3 HFE-356PCC3 HFE-356PCF2 HFE-356PCF3 HF
20、E-374PCF2 HFE-7100 HFE-7200 HG-01 HG-10 H-GALDEN 1040X METHANE NF3 NITROUS OXIDE PERFLUOROBUTANE PERFLUOROHEXANE PERFLUOROPENTANE PERFLUOROPROPANE SF5CF3 SF6,HFC-161 HFC-227EA HFC-23 HFC-236CB HFC-236EA HFC-236FA HFC-245CA HFC-245FA HFC-32 HFC-365MFC HFC-41 HFC-4310MEE HFE-125 HFE-134 HFE-143A HFE-2
21、27EA HFE-236EA2 HFE-236FA HFE-245CB2 HFE-245FA1 HFE-245FA2 HFE-254CB2 HFE-263FB2 HFE-329MCC2,Classification: Carcinogens,1,1,1,2-TETRACHLOROETHANE 1,1,2,2-TETRACHLOROETHANE 1,1,2-TRICHLOROETHANE 1,1-DICHLOROETHANE 1,1-DICHLOROETHYLENE 1,1-DIMETHYLHYDRAZINE 1,2,3,4,6,7,8-HEPTACHLORODIBENZOFURAN 1,2-D
22、IBROMOETHANE 1,2-DICHLOROETHANE 1,2-DICHLOROPROPANE 1,3-BUTADIENE 1,3-DICHLOROBENZENE 1,3-DICHLOROPROPENE 1,4-DICHLOROBENZENE 1,4-DIOXANE 11,12-BENZOFLUORANTHENE 1-CHLORO-2,3-EPOXYPROPANE 1-CHLORO-4-NITROBENZENE 1-NAPHTYL N-METHYLCARBAMATE 2,3,4,7,8-PENTACHLORODIBENZOFURAN,1,2-DIBROMOETHANE 1,2-DICH
23、LOROETHANE 1,2-DICHLOROPROPANE 1,3-BUTADIENE 1,3-DICHLOROBENZENE 1,3-DICHLOROPROPENE 1,4-DICHLOROBENZENE 1,4-DIOXANE 11,12-BENZOFLUORANTHENE 1-CHLORO-2,3-EPOXYPROPANE 1-CHLORO-4-NITROBENZENE 1-NAPHTYL N-METHYLCARBAMATE 2,3,4,7,8-PENTACHLORODIBENZOFURAN 2,3,7,8-TCDD 2,3,7,8-TETRACHLORODIBENZOFURAN 2,
24、4,6-TRICHLOROPHENOL 2,4,6-TRINITROTOLUENE 2,4-D ACETIC ACID (2,4-DICHLOROPHENOXY)- 2,4-DIAMINOTOLUENE 2,4-DINITROTOLUENE 2,6-DINITROTOLUENE etc,Characterization,Characterization is the quantification of the contribution of each inventory flow to each impact of interest Whereas inventory analysis can
25、 be seen as a model which includes all types of complications (cut-off, multifunctionality, etc.) characterization uses the results of complicated models: Fate and transport Exposure assessment Dose-response Etc.,Characterization,Computational structurewhere hi= the contribution of the product syste
26、m to impact i qij= the equivalency (or characterization) factor for intervention j for impact i gj= components of the inventory vector for intervention j (remember g=Bs),Global Warming Potentials as Equivalency Factors,Process X emits 5 kg methane and 4 kg nitrous oxide gCH4 = 5 kg, gN2O = 4 kg The
27、equivalency factors are the 100-year Global Warming Potentials (GWPs): qglobal warming- CH4 = GWPCH4 = 21 g CO2/ g CH4 qglobal warming- N2O = GWPN2O = 310 g CO2/ g N2O THEREFORE the potential contribution to global warming for methane is qglobal warming- CH4 x gCH4 = 5,000 g x 21 g CO2/ g CH4=105,00
28、0 g CO2 AND the total contribution of Process X to global warming is: hglobal warming = (105,000 + 1,240,000) g CO2 = 1,345 kg CO2,Impact Assessment,Characterization Inventory materials are weighted by their contribution to different impacts Normalization Characterization results are compared to imp
29、ortant levels of impacts (at the national level, for the technology being replaced, etc.) Valuation Impacts are weighted by their value to decision makers,Biodiesel LCAs,Biodiesel is a renewable diesel fuel substitute. can be made from a variety of natural oils and fats. Biodiesel is made by chemica
30、lly combining any natural oil or fat with an alcohol such as methanol or ethanol. Methanol has been the most commonly used alcohol in the commercial production of biodiesel. In Europe, biodiesel is widely available in both its neat form (100% biodiesel, also known as B100) and in blends with petrole
31、um diesel. European biodiesel is made predominantly from rapeseed oil (a cousin of canola oil). In the United States, initial interest in producing and using biodiesel has focused on the use of soybean oil as the primary feedstock mainly because the United States is the largest producer of soybean o
32、il in the world.,From Sheehan, et al. (1998) “Life Cycle Inventory of Biodiesel and Petroleum Diesel for Use in an Urban Bus,”NREL/SR-580-24089 UC Category 1503,Why LCA of Biodiesel?,Proponents of biodiesel as a substitute for diesel fuel (in blends or in its neat form) can point to a number of pote
33、ntial advantages for biodiesel that could support a number of strategies for addressing national issues: Reducing dependence on foreign petroleum Leveraging limited supplies of fossil fuels. Mitigating greenhouse gas emissions. Reducing Air Pollution and Related Public Health Risks. Benefiting our d
34、omestic economy.,From Sheehan, et al. (1998) “Life Cycle Inventory of Biodiesel and Petroleum Diesel for Use in an Urban Bus,”NREL/SR-580-24089 UC Category 1503,Biodiesel Synthesis Pathways,From Holbein, et al. (2004) “Canadian Biodiesel Initiative: Aligning Research Needs and Priorities With the Em
35、erging Industry,” Prepared for Natural Resources Canada,Biodiesel LCAs,Several biodiesel LCAs have been performed (US, Canada, Germany) The foremost US study was a LCI funded by the USDOE and US Department of Agriculture:,Sheehan, et al. (1998) “Life Cycle Inventory of Biodiesel and Petroleum Diesel
36、 for Use in an Urban Bus,” at http:/www.nrel.gov/docs/legosti/fy98/24089.pdf,The US Biodiesel LCA,Reductions in Petroleum and Fossil Energy Consumption Substituting 100% biodiesel (B100) for petroleum diesel in buses reduces the life cycle consumption of petroleum by 95%. This benefit is proportiona
37、te with the blend level of biodiesel used. When a 20% blend of biodiesel and petroleum diesel (B20) is used as a substitute for petroleum diesel in urban buses, the life cycle consumption of petroleum drops 19%. It was found that the production processes for biodiesel and petroleum diesel are almost
38、 identical in their efficiency of converting a raw energy source (in this case, petroleum and soybean oil) into a fuel product. The difference between these two fuels is in the ability of biodiesel to utilize a renewable energy source. Biodiesel yields 3.2 units of fuel product energy for every unit
39、 of fossil energy consumed in its life cycle. The production of B20 yields 0.98 units of fuel product energy for every unit of fossil energy consumed. By contrast, petroleum diesels life cycle yields only 0.83 units of fuel product energy per unit of fossil energy consumed. Such measures confirm the
40、 “renewable” nature of biodiesel.,From Sheehan, et al. (1998) “Life Cycle Inventory of Biodiesel and Petroleum Diesel for Use in an Urban Bus,”NREL/SR-580-24089 UC Category 1503,The US Biodiesel LCA,Reductions in CO2 Emissions Given the low demand for fossil energy associated with biodiesel, it is n
41、ot surprising that biodiesels life cycle emissions of CO2 are substantially lower than those of petroleum diesel. Biodiesel reduces net emissions of CO2 by 78.45% compared to petroleum diesel. For B20, CO2 emissions from urban buses drop 15.66%. In addition, biodiesel provides modest reductions in t
42、otal methane emissions, compared to petroleum diesel. Methane is another, even more potent, greenhouse gas. Thus, use of biodiesel to displace petroleum diesel in urban buses is an extremely effective strategy for reducing CO2 emissions.,From Sheehan, et al. (1998) “Life Cycle Inventory of Biodiesel
43、 and Petroleum Diesel for Use in an Urban Bus,”NREL/SR-580-24089 UC Category 1503,The US Biodiesel LCA,Changes in Air Pollutant Emissions The effect of biodiesel on air quality is more complex. Biodiesel, as it is available today, offers substantial improvements in some air pollutants, while it lead
44、s to increases in others. The use of B100 in urban buses results in substantial reductions in life cycle emissions of total particulate matter, carbon monoxide and sulfur oxides (32%, 35% and 8% reductions, respectively, relative to petroleum diesels life cycle).,From Sheehan, et al. (1998) “Life Cy
45、cle Inventory of Biodiesel and Petroleum Diesel for Use in an Urban Bus,”NREL/SR-580-24089 UC Category 1503,The US Biodiesel LCA,Particulates, Carbon Monoxide and Sulfur Oxides. are targeted by EPA because of the important role they play in public health risks, especially in urban areas where the ac
46、ute effects of these pollutants may be greater. Given the concern over urban air quality, it is important to note that most of these reductions occur because of lower emissions at the tailpipe. For buses operating in urban areas, this translates to an even greater potential benefit: Tailpipe emissio
47、ns of particulates less than 10 microns in size are 68% lower for buses run on biodiesel (compared to petroleum diesel). In addition, tailpipe emissions of carbon monoxide are 46% lower for buses run on biodiesel (compared to petroleum diesel). Biodiesel completely eliminates emissions of sulfur oxi
48、des at the tailpipe. The reductions in air emissions reported here are proportional to the amount of biodiesel present in the fuel. Thus, for B20, users can expect to see 20% of the reductions reported for biodiesel used in its neat form (B100).,From Sheehan, et al. (1998) “Life Cycle Inventory of B
49、iodiesel and Petroleum Diesel for Use in an Urban Bus,”NREL/SR-580-24089 UC Category 1503,The US Biodiesel LCA,Increased Emissions of Nitrogen Oxides (NOx) NOx is one of three pollutants implicated in the formation of ground level ozone and smog in urban areas (NOx, CO and hydrocarbons). The use of
50、B100 in urban buses increases life cycle emissions of NOx by 13.35%. Blending biodiesel with petroleum proportionately lowers NOx emission. B20 exhibits a 2.67% increase in life cycle emissions of NOx. Most of this increase is directly attributable to increases in tailpipe emissions of NOx. B100, for example, increases tailpipe levels of NOx by 8.89%.,
