摘要
Assessing and accounting for material consumption and environmental impact are necessary to measure environmental externalities of the aluminum industry and to construct an ecological civilization.In this research,life cycle assessment(LCA)theory was used to assess the environmental impact of primary aluminum based on the lime soda Bayer process and different power generation modes,and the sources and distributions of the four selected impact categories were analyzed.The results show that,(1)Negative environmental impact of aluminum industry generally occurs from alumina extraction,carbon anode fabrication and electrolysis,particularly electrolysis and alumina extraction.Primary energy demand(PED),water use(WU),global warming potential(GWP)and freshwater eutrophication potential(FEP)are main environmental impact categories.(2)The environmental load with thermal power is higher than that with hydropower,e.g.,for the former,the greenhouse gas emission coefficient of 21800 kg CO2 eq/t(Al)will be generated,while for the latter,4910 kg CO2 eq/t(Al)will be generated.(3)Both power mode methods reflect the energy structure,whereas direct emissions reflect the technical level,indicating the potential for large energy savings and emission reductions,and some policies,related to clean power,energy efficiency and technological progress,should be made for emission reduction.
在当前生态文明建设的背景下,对原铝生产过程中的物料消耗、环境影响进行评估和核算,是进行环境外部性计量和促进铝行业绿色发展的基础性工作。为此,本文作者利用生命周期评价理论,采用拜耳法制备氧化铝工艺,根据不同发电方式分别对原铝生命周期内的环境影响进行评估,并分析4种主要环境影响类型的来源和分布。结果表明:(1)铝工业的负面环境影响一般来自于氧化铝冶炼、碳阳极制备和电解工艺,尤其是电解和氧化铝工艺。初级能源消耗(PED)、水资源消耗(WU)、温室效应(GWP)和淡水富营养化(FEP)是主要的环境影响类型。(2)火力发电模式生产原铝产生的环境负荷明显高于水力发电模式(前者温室气体排放系数为21800 kg CO2 eq/t(Al),后者为4910 kg CO2 eq/t(Al))。(3)反映能源结构的发电方式和反映技术水平的直接排放所占比重揭示中国铝行业巨大的节能减排潜力,可制定发展清洁发电、提高能源效率和促进技术进步等相关的政策和措施。
基金
Projects(71633006,71403298) supported by the National Natural Science Foundation of China
Projects(14YJCZH045,15YJCZH019) supported by the Ministry of Education of Humanities and Social Science,China
作者简介
Corresponding author: Yao-qi GUO;Tel:+86-13787798224;E-mail: guoyaoqi@csu.edu.cn.
