生命周期评价在废旧电脑管理策略中的应用

生命周期评价在废旧电脑管理策略中的应用

吕彬，杨建新

中国科学院生态环境研究中心城市与区域生态国家重点实验室，北京，100085

摘要：

近年来，随着中国经济的快速发展，电脑等电子信息产品更新速度加快，随之而来，废旧电脑大量产生，而且产生速度也在持续增长。废旧电脑中既含有可回收材料（金属、塑料等），又含有有毒物质（铅、汞、含溴阻燃剂等）。若对其进行不当处理，不仅造成环境污染，也会浪费大量资源。因此，需要对废旧电脑的管理策略进行评价与分析，为制订相应的环境管理政策提供支持。生命周期评价可以对各种废物处理策略的环境影响进行量化评价，可作为一种有效工具分析废旧电脑的管理策略。

本文选取台式机电脑电源作为研究对象。电脑电源是电脑中较易损坏的部分，在电脑生命周期内其报废量要高于电脑本身，其中可再利用的元件也较多。在目前中国废旧电脑回收处理实践中，针对电脑电源具有三种生命终期处理选择：整体再利用，元件再利用和材料回收。由于再利用与回收材料的再生涉及到产品的第二次生命周期，因此本文使用了两种不同的功能单位进行了两次生命周期评价。第一种功能单位是处理一定数量的废旧电脑电源，第二种是废旧电源经过处理后的第二次生命周期正常向电脑主机供电的时间。清单数据以国内基础数据与废旧电脑处理厂的实地调研数据为主，使用Eco-invent数据库作为补充。废旧电脑具有资源特性与污染特性，而国内目前的废旧电脑回收处理系统主要以深度人工拆解为主，而且在材料回收过程中造成了一定程度的污染。因此，本研究重点考虑全球尺度的资源耗竭影响以及区域的人类健康与生态系统损害程度。实际的评价模型采用了Eco-Indicator 99模型。

评价结果表明，在第一次生命周期评价中，以固定的淘汰量作为功能单位，整体再利用具有最优的环境表现，元件再利用次之，材料回收环境表现最差，但元件再利用与材料回收之间的差别不大。而在第二次生命周期评价中，使用产品二次生命周期的正常运行时间作为功能单位，整体再利用依然最优，材料回收次之，元件再利用最差，并且后二者差别较大。由于数据可得性、分配原则以及生命期假设等都存在较大的不确定性，因此，本文的结论还需要进一步的研究与讨论。

关键词：废旧电脑  生命周期评价 生命终期策略 再利用 材料回收

Application of LCA in the End-of-Life strategies of obsolete PCs in China

            Bin Lu, Jianxin Yang

State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences,

Chinese Academy of Sciences, Beijing, 100085, China

Abstract:

With the fast economy growth in China, Personal Computers (PCs) are penetrated more deeply in the society and are upgraded more frequently. As a result, a large quantity of obsolete PCs is and will be generated. It becomes an urgent problem to choose effective End-of-Life (EoL) strategy for obsolete PCs to balance the materials recovery and related pollution prevention. In this study, Life Cycle Assessment (LCA) is used to assess environmental impacts of different EoL options of PCs.

Power Supply Unit (PSU) of desktop computer is taken as the target object due to its vulnerability and its massive reusable components. In the end of life of PSU, such three scenarios are built based on practical activities in China as Unit Reuse (UR), Component Reuse (CR) and Materials Recovery (MR). Because UR, CR and MR are all concerned with second life cycle, two kinds of functional units are used within two life cycle systems in this study. The first functional unit is a certain number of obsolete PSUs to be treated, and the second one is a fixed period of normal operation time of the second life cycle of PSU. Eco-Indicator 99 method is used in the life cycle impact assessment (LCIA), because of the impact on global resource and damage to regional ecosystem and health of human along with treatment of obsolete PCs.

The LCA results show that: In the first LCA with the first functional unit, the classical EoL strategies hierarchy is reasonable, in which UR is most environmentally friendly followed by CR and MR. In the second LCA with the second functional unit, UR is still best in environmental performance, but MR is better than CR. However, there are significant system uncertainties such as allocation methods, data availability and quality and life span assumptions, which need further study.

Keywords:  Obsolete PCs   End-of-Life    Life Cycle Assessment    Reuse   Materials Recovery