三段氨吸法回收硫酸尾气副产固体亚硫酸铵

Co-production of solid ammonium sulfite by three-stage absorption of SO_2 in sulphuric acid tail gas with ammonia

接触法硫铁矿制酸工艺排出的尾气中二氧化硫一般为0.2%～0.5%(体积分数,下同),酸雾一般为0.004%～0.008%,目前中国普遍采用一转一吸或两转两吸流程来吸收硫酸尾气,可使二氧化硫含量降至0.01%～0.1%。但随着硫酸产能的增大或企业扩产,二氧化硫排放总量仍然大大超过环保部门的控制要求。结合武汉中东化工有限公司硫酸车间的实际生产情况,总结了采取三段氨吸法处理硫酸尾气的技术改造。

The offgas discharged during the preparation of acids from pyrite by contacting method contains generally 0.2%~0.5%（volume fraction,same below） SO2 and 0.004%~0.008% acid mist.At present,＇one conversion and one absorption＇ process or ＇two conversions and two absorptions＇ process are commonly used in China to absorb sulphuric acid tail gas such that the SO2 content thereof is as low as about 0.01%~0.1%.With the increase of sulphuric acid producti-vity or the capacity expansion of enterprises,however,the total emission of SO2 still overpasses significantly the requirement of Environmental Protection Department.Technical improvement on treating sulphuric acid tail gas by three-stage amine absorption process was summarized,based on the practice carried out in the sulphuric acid workshop of Zhongdong Chemical Engineering Limited Corporation of Wuhan.