铝电解生产过程全氟化碳排放现状与分析

Current Situation and Analysis of Perfluorocarbon Emissions from Aluminum Electrolysis Production Process

全氟化碳(PFCs)是目前被认为增温潜势非常强的温室气体,铝电解生产过程中产生的全氟化碳包括CF_(4)和C_(2)F_(6)。我国电解铝产量连续十多年位居世界首位,降低铝电解生产过程中PFCs排放是铝工业温室气体减排的路径之一。本文分析了铝电解PFCs的产生机理和排放情况,并以某企业300 kA系列电解槽为例,测量计算其PFCs的CO_(2)当量排放,并与按照指南缺省值核算的PFCs排放数据进行对比。对比结果表明,按缺省值计算的PFCs排放量为0.2523 t CO_(2)e/t-Al,远小于测量值0.8839 t CO_(2)e/t-Al,无法体现企业的真正PFCs排放情况。根据铝电解析出碳氟化合物的反应机理,降低铝电解生产PFCs排放的直接途径是减少阳极效应次数和缩短效应时间。因此,为了减少PFCs排放,从电解槽优化设计、槽控系统升级、工艺技术优化、大宗原料把控、设备运行维护等建方面提出了建议。

Perfluorocarbons(PFCs)are currently considered to be greenhouse gases with a very strong warming potential.The perfluorocarbons produced during the production of aluminum electrolysis include CF_(4)and C_(2)F_(6).China s electrolytic aluminum production has ranked first in the world for more than ten years.Reducing PFCs emissions during aluminum electrolysis production is one of the ways to reduce greenhouse gas emissions in the aluminum industry.In this paper,the generation mechanism and emission of PFCs in aluminum electrolysis were analyzed.Taking a 300 kA series electrolytic cell of an enterprise as an example,the CO_(2)equivalent corresponding to PFCs emission was measured and calculated,and compared with the PFCs emission data calculated according to the default value of the guide.The comparison results show that the CO_(2)equivalent intensity of PFCs emissions is 0.2523 t CO_(2)e/t-Al,which is far less than the measured value of 0.8839 t CO_(2)e/t-Al,which cannot reflect the real PFCs emissions of enterprises.The direct way to reduce PFCs emissions from aluminum electrolysis production is to reduce the number of anode effects and shorten the effect time.Therefore,in order to reduce PFCs emissions,suggestions are made from the aspects of electrolytic cell optimization design,cell control system upgrade,process technology optimization,bulk raw material control,equipment operation and maintenance,etc.