请帮忙找一份有关于产品生命周期评价（LCA）的英语资料2000单词~急用~谢谢
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发布时间：2022-05-06 15:01
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时间：2023-10-10 05:19
The goal of LCA is to compare the full range of environmental damages assignable to procts and services, to be able to choose the least burdensome one. The term 'life cycle' refers to the notion that a fair, holistic assessment requires the assessment of raw material proction, manufacture, distribution, use and disposal including all intervening transportation steps necessary or caused by the proct's existence. The sum of all those steps - or phases - is the life cycle of the proct. The concept also can be used to optimize the environmental performance of a single proct (ecodesign) or to optimize the environmental performance of a company. Common categories of assessed damages are global warming (greenhouse gases), acidification, smog, ozone layer depletion, eutrophication, eco-toxicological and human-toxicological pollutants, desertification, land use as well as depletion of minerals and fossil fuels.
A classic application of LCA is, for example, to determine whether beverage packaging made of glass is more or less burdensome than plastic bottles. All life cycle phases for both options need to be investigated. For glass bottles those phases are the mining of glass minerals from the biosphere, bottle proction, bottling, all transports, and final disposal. For plastic bottles they are raw oil proction, oil refining, polymer proction, bottle proction, bottling, transports, and final disposal. For all necessary auxiliary materials or services similar process chains need to be considered: for example, a catalyst needed ring the polymer proction needs to be included with its life cycle pro rata. Ecological interventions generated along these complex process chains are inventoried, like emissions to air, water or soil, resources taken from the biosphere, land uses, or noise generation. These interventions are then interpreted relating to their severity and compared for both options to make a fair and holistic judgement. Simultaneously it is possible to establish which processes in a proct's life cycle are important contributors to damages and gain an understanding on the major determinants of environmental performance of the assessed procts.
The proceres of life cycle assessment (LCA) are part of the ISO 14000 environmental management standards: in ISO 14040:2006 and 14044:2006. (ISO 14044 replaced earlier versions of ISO 14041 to ISO 14043.)
Green Seal is a well known non-profit organization that utilizes life-cycle analysis to evaluate and certify procts and services that have a lesser impact on the environment and human health.
[edit] Four main phases
According to the ISO 14040[1] and 14044[2] standards, a Life Cycle Assessment is carried out in four distinct phases.
[edit] Goal and scope
In the first phase, the LCA-practitioner formulates and specifies the goal and scope of study in relation to the intended application. The object of study is described in terms of a so-called functional unit. For the example of comparing glass vs. plastic bottles, the functional unit could be “1 liter bottle container for refrigerated juices”. Comparing 1 kg of plastic bottles directly with 1 kg of glass bottles, disregarding the packed volume, would not be an appropriate functional unit for the desired functionality of bottles. Apart from describing the functional unit, the goal and scope should address the overall approach used to establish the system boundaries. The system boundary determines which unit processes are included in the LCA and must reflect the goal of the study. In recent years, two approaches to system delimitation have emerged. These are often referred to as ‘consequential’ modeling and ‘attributional’ modeling. Finally the goal and scope phase includes a description of the method applied for assessing potential environmental impacts and which impact categories that are included.
[edit] Life cycle inventory
This second phase 'Inventory' involves modelling of the proct system, data collection, as well as description and verification of data. This implies data for inputs and outputs for all affected unit processes that compose the proct system. The inputs and outputs include inputs of materials, energy, chemicals and 'other' - and outputs in the form of air emissions, water emissions or solid waste. Other types of exchanges or interventions such as radiation or lanse should also be included.
The data must be related to the functional unit defined in the goal and scope definition. Data can be presented in tables and some interpretations can be made already at this stage. The results of the inventory is an LCI which provides information about all inputs and outputs in the form of elementary flow to and from the environment from all the unit processes involved in the study.
[edit] Life cycle impact assessment
The third phase 'Life Cycle Impact Assessment' is aimed at evaluating the contribution to impact categories such as global warming, acidification etc. The first step is termed characterization. Here, impact potentials are calculated based on the LCI results. The next steps are normalization and weighting, but these are both voluntary according the ISO standard. Normalization provides a basis for comparing different types of environmental impact categories (all impacts get the same unit). Weighting implies assigning a weighting factor to each impact category depending on the relative importance.
[edit] Interpretation
The phase stage 'interpretation' is the most important one. An analysis of major contributions, sensitivity analysis and uncertainty analysis leads to the conclusion whether the ambitions from the goal and scope can be met. More importantly: what can be learned form the LCA? All conclusions are drafted ring this phase. Sometimes an independent critical review is necessary, especially when comparisons are made that are used in the public domain.
[edit] Variants
[edit] Cradle-to-grave
Cradle-to-grave is the full Life Cycle Assessment from manufacture ('cradle') to use phase and disposal phase ('grave'). For example, trees proce paper, which is recycled into low-energy proction cellulose (fiberised paper) insulation, then used as an energy-saving device in the ceiling of a home for 40 years, saving 2,000 times the fossil-fuel energy used in its proction. After 40 years the cellulose fibers are replaced and the old fibres are disposed of, possibly incinerated. All inputs and outputs are considered for all the phases of the life cycle.
[edit] Cradle-to-gate
Cradle-to-gate is an assessment of a partial proct life cycle from manufacture ('cradle') to the factory gate, i.e. before it is transported to the consumer. The use phase and disposal phase of the proct are usually omitted. Cradle-to-gate assessments are sometimes the basis for environmental proct declarations (EPD).
[edit] Cradle-to-Cradle
Cradle-to-cradle is a specific kind of cradle-to-grave assessment, where the end-of-life disposal step for the proct is a recycling process. From the recycling process originate new, identical procts (e.g. glass bottles from collected glass bottles), or different procts (e.g. glass wool insulation from collected glass bottles).
Well-to-wheel
Well-to-wheel is the specific LCA of the efficiency of fuels used for road transportation. The analysis is often broken down into stages such as "well-to-station" and "station-to-wheel, or "well-to-tank" and "tank-to-wheel".
The factor "Tp = Petroleum refining and distribution efficiency = 0.830" from the DOE regulation accounts for the "well-to-station" portion of the gasoline fuel cycle in the USA. To convert a standard Monroney sticker value to a full cycle energy equivalent, convert with Tp. For example, the Toyota Corolla is rated at 28 mpg station-to-wheel. To get the full cycle value, multiply mpg by Tp=0.83 to account for the refining and transportation energy use - 23.2 mpg full cycle. The same adjustment applies to all vehicles fueled completely with gasoline, therefore, Monroney sticker numbers can be compared to each other with or without the adjustment. A recent study examined well-to-wheels energy and emission effects of various vehicle and fuel systems [
