LCA 产品生命周期分析解读课件.ppt
Life Cycle Assessment LCA,Why LCA?Quantify the environmental impact of a product or process*Answer questions about product life cyclesCompare two alternatives - which is greener?Identify the harmful stages of the life cycle*or carry out a qualitative assessment quick but subjective,The LCA system,+ Transport,Waste management,ENERGY,RAWMATERIALS,SOLIDWASTE,UTILITY (FUNCTION),system boundary,Stages of an LCA: 1 goal, scope and units,Example electric and disposable razors- why are we doing it?- what is the system?- what is the functional unit?,- to improve designs- manufacture, use and disposal- 1 years close shaves at 1 per day,The system processes - flowcharts,Example: wooden tableIdentifies the system boundaryFlows in and out materials, energy (E) and transport use (T)Shows all the processes involved in the life cycleExcludes selected processes e.g. minor ones, or unknownShows end-of-life alternatives, with probability,Flowchart exercise 1: electric shaver,Shaver disposal,Landfill,SOLIDWASTE,UTILITY (shaving),system boundary,UK Elec. generation,E,Electronics production,Recycling,30%,70%,E,E,E,T,whats missing?,T,Flowchart 2: disposable razor & blades,Razor disposal,Landfill,SOLIDWASTE,UTILITY (shaving),system boundary,UK Elec. generation,E,E,T,Packaging production,whats missing?,T,Blades,The functional unit,Milk packaging methods Goal of study: to compare packaging materials and designs from dairy to consumer, including disposal.Functional unit: 1000 litres of packed milk, for one trip.Light bulbs Goal: to compare alternative light bulb designs for consumers.Functional unit: 10,000 hours illumination at a given brightness (x lumens).Commuting Goal: to compare different modes of transport to work, e.g. bus, bike, carFunctional unit: 1 years commuting 10km/day by 100 peopleExercises:Food transport (to compare road and rail for food from farm to supermarket)House design (to compare the energy and materials use of alternative designs)Refrigerators (to compare different models of various sizes),Food transport: 100 ton.kmHouse design: 500m2 dwelling in a specified climateRefrigerator: 2m3 volume, cooled by 20 for 1 year, 5kg food added/week,Stage 2: Inventory analysis,A complete record of quantities of:Inputs of energy, fuel, etc.Raw materials by typeTransport used (hence fuels, energy, etc)Outputs to air, water; solid waste - many chemicals listed here,The inventory is normally a spreadsheet or table of many entries,Example: shaving systemsInventory of processes includes:Polymers from oil; copper; etc.transport energy and emissionsdisposal solid waste and air pollution,Stage 3: Impact assessment,The inventory is usually translated into a set of environmental effects:,Fuels & energyRaw materials(Land)(Water)Solid wasteAir: CO2, NOX, SOX, etc.Water: Acid, nitrates, phosphates, etc.Waste heat,Use of non-renewable resourcesGlobal warmingOzone depletionHuman toxicityEcosystem toxicityAcidificationEutrophicationCOD, BOD in waterSmogNoise. etc.,?,Impact assessment - classification,The correspondence between inventory (aspects) and effects is not one-to-one:,Fuels & energyRaw materials(Land)(Water)Solid wasteAir: CO2, NOX, SOX, etc.Water: Acid, nitrates, phosphates, etc.Waste heat,Use of non-renewable resourcesGlobal warmingOzone depletionHuman toxicityEcosystem toxicityAcidificationEutrophicationCOD, BOD in waterSmogNoise. etc.,Impact assessment,ExampleImpact of electric shaver:resource depletion (oil, copper)global warming (CO2) from elec.toxicity from transport emissionsetc.,Impact of razor & blades:global warming (CO2, CH4)Eco-toxicity from waste waterLand use from landfill of waste inc. packagingetc.,Impact assessment - characterisation,The totals for each effect can then be added up and compared:,Impact assessment - valuation,The last stage, optional - and controversialIf subjective values are placed on health, ecosystems, etc. - then the impacts can be valued in a single unitMost common example: Dutch Ecoindicator methodsuggests relative importance of impactsthe whole LCA can be expressed in terms of Pointsonly valid for a country or region, e.g. ECgood for internal comparisons; used by PhilipsE.g. Electric shaver250 points to make, 1 to charge= 2 pts per shaveRazor & blades30 pts handle, 12 per cartridge= 3 pts per shave,Stage 4 interpretation,Example: shavingInterpreting the study:Electric shaver - major impact in manufacture and charging, hence large GW impactRazor and blades more waste, depending on assumptions on blade durability, method of heating water,hence better understanding and design ideas,LCA software,Database contains inventory for common materials, energy sources, transport types and waste strategiesdata quality is important; is it reliable?Can carry out impact assessment if desiredEasy software: EcoIT,for products and packaging; see http:/www.pre.nl/eco-it/default.htmMore detailed: Simapro Both from (Pre Consultants, NL) using Ecoindicator method for valuation. See www.pre.nl,
