燃煤烟气脱硝副产物硫酸氢铵/硫酸铵沉积与分解特性研究

Study on deposition and decomposition characteristics of ammonium bisulfate/ammonium sulfate as by-product of denitration in coal-fired flue gas

搭建模拟空预器多段控温实验台,研究不同SO3浓度、SO3/NH3比、不同温度下硫酸氢铵(ABS)与硫酸铵(AS)的生成、沉积与分解特性。在高温条件下发生的初始沉积部位,沉积物均为液态ABS,其失重特性与纯ABS基本一致。而在低温条件下,则根据SO3/NH3比的不同沉积物特性有所变化。SO3/NH3比为2∶1时,沉积物为H2O、H2SO4与少量ABS的混合物,以密集液滴形态存在,呈多段分解特性;SO3/NH3比为1∶1与1∶2时,沉积物为分散性较强的干AS粉末,分解特性与纯AS基本一致。研究结果可为ABS防控提供指导。

A special multi-stage temperature control experimental bench for simulated air preheater was built,and the generation,deposition and decomposition of ammonium bisulfate(ABS)and ammonium sulfate(AS)under different SO3 concentrations,SO3/NH3 ratio,and different temperature conditions were studied.At the initial deposition site under high temperature conditions,the deposits are all liquid ABS,and its weight loss characteristics are basically the same as pure ABS.However,under lower temperature ranges,the characteristics of the sediments will change with SO3/NH3.When SO3/NH3 is 2∶1,the sediments are the mixture of H2O,H2SO4 and a small amount of ABS,which exists in the form of dense droplets,and it has multi-stage decomposition characteristics.When SO3/NH3 is 1∶1 and 1∶2,the sediments are the dry AS power with strong dispersion,and its decomposition characteristics are basically the same as pure AS.The results can provide guidance for ABS prevention and control.