湿法脱硫配套烧结烟气脱硝装置设计浅析

Brief Analysis on Design of Flue Gas Denitration Unit for Wet Desulfurization of Sintering Flue Gas

随着我国大气污染防治工作的有序推进,钢铁行业大气污染物净化处理已经成为目前环保工程的热门问题。烧结烟气中的SO2、氮氧化物和二噁英等污染物是钢铁行业产生的主要污染物,针对新的排放要求,对烧结烟气脱硝改造工程提出了最适合烧结烟气湿法脱硫的配套烟气SCR脱硝技术方案,并对SCR脱硝工程设计中的注意事项进行了分析总结。烧结机外排烟气量影响因素很多,单纯依据烧结主抽风机和湿法脱硫系统烟气量的增加值来确定脱硝系统烟气量会导致脱硝系统增压风机选型偏小,建议在正确计算基础上,额外增加不低于20%的设计裕量;烧结烟气SCR脱硝催化剂应选择耙式吹灰器,尽可能选用过热蒸汽作为吹灰介质,蒸汽过热度不低于50℃,无法提供过热蒸汽时,应采用加热后的压缩空气或氮气作为吹灰气源,同时,对压缩空气和氮气的参数应有明确的要求;另外,需要注意湿电、烟道等的防腐和排水等。

With the orderly progress of air pollution prevention and control in China,the purification treatment of air pollutants in the steel industry has become a hot spot in environmental protection projects.The pollutants such as SO2,nitrogen oxides and dioxins in the sintering flue gas are the main pollutants produced by the steel industry.To meet the new emission requirements,this paper proposes the most suitable technology of SCR denitration for the wet desulfurization of sintering flue gas,and summarizes the precautions in the design of SCR denitration projects.There are many factors affecting the amount of flue gas discharged from the sintering machine.Determining the amount of flue gas in the design of SCR denitration system simply based on the increase of flue gas from sintering main exhauster and wet desulfurization system will lead to the se-lection of a relatively smaller booster fan of the denitration system.It is suggested that an additional design margin of no less than 20% should be added on the basis of correct calculation.Rake soot blower should be selected for the catalyst of SCR denitration system,and superheated steam should be used as the soot blowing medium as far as possible.The superheat of steam should be not lower than 50 ℃.If it is impossible to provide superheated steam,heated compressed air or nitrogen should be used as the source of soot blowing gas.Meanwhile,there should be clear requirements for the parameters of compressed air and nitrogen.In addition,attentions should be paid to the anticorrosion and drainage of Wet ESP and flue duct.