基于超低排放典型工艺的钢铁烧结模拟烟气冷凝特性研究
Research on gas condensation characteristics of sintering simulation based on ultra-low emission typical process
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摘要: 钢铁烧结烟气超低排放背景下,为有效控制可凝结颗粒物(CPM)产生和有色烟羽问题,论文针对钢铁烧结烟气的“半干法(干法)脱硫 + 中低温SCR脱硝”超低排放典型工艺,参考稀释间接法原理设计模拟冷凝实验装置,结合大气气溶胶相关热力学及动力学模拟计算结果,考察探究了烧结烟气“NH3、HCl、SO3、H2O”各组分冷凝的相互影响及其机制。实验研究结果表明,逃逸NH3的存在将引发SO3成核速率显著提升,形成潮解点较低、易团聚的硫酸盐气溶胶,使得SO3平均冷凝比提升至84%;而HCl则主要以离子态形式存在于硫酸盐气溶胶中,平均冷凝可达80%。HCl和SO3对NH3冷凝为促进作用,效果排序为:HCl + SO3 > SO3 > HCl,NH3的平均冷凝比可从27%最高升至78%,并且初始NH3浓度改变对CPM冷凝总量的影响最大。研究结果可为有效开展烧结烟气可凝结颗粒物控制提供了有益参考。Abstract: Under the background of ultra-low emission of sintering flue gas, in order to effectively control the generation of condensable particulate matter (CPM) and the problem of colored plume, this paper aimed at the ultra-low emission typical process of "semi-dry method (dry method) desulfurization + medium-low temperature SCR denitrification" of sintering flue gas, and designed the simulation condensation experiment device by referring to the principle of dilution indirect method. The interaction and mechanism of condensation of NH3, HCl, SO3 and H2O in sintering flue gas were investigated based on the thermodynamic and kinetic simulation results of atmospheric aerosol. The experimental results show that the existence of escaping NH3 will cause the nucleation rate of SO3 to increase significantly. Form sulfate aerosols with low deliquation point and easy agglomeration, so that the average condensation ratio of SO3 increases to 84%. HCl exists mainly in the form of ion in sulfate aerosol, with an average condensation ratio up to 80%. HCl and SO3 promote the condensation of NH3, and the order of effect is: HCl + SO3 > SO3 > HCl. The average condensation ratio of NH3 can be increased from 27% to 78%, and the change of initial NH3 concentration has the greatest impact on the total condensation of CPM. The results can provide useful reference for effective control of condensable particles in sintering flue gas.
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Key words:
- sintering /
- inorganic component /
- condensation /
- thermodynamic equilibrium /
- treatment measures
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