Process Development of Effective Semi-Dry Flue Gas Desulfurization by New Type of Fluidized Bed (Powder Particle Spouted Bed)

为开发一种新型半干法烟气脱硫工艺，将粉末颗粒喷射床（PPSB）应用于低温脱硫工艺。将平均粒径为400 ~ 1000mum的粗颗粒与含SO_2 500 ~ 1500ppm的气体在120 ~ 200‰的温度下进行流态化处理，得到的SO_2吸附剂浆料（如熟石灰）连续入床。SO_2气体在反应器中与SO_2吸附剂反应，反应后的吸附剂被带出反应器，由袋式过滤器收集。考察了SO_2吸附剂种类、粒径、饱和温度、Ca/S比、反应温度和气速对SO_2脱除效果的影响。SO_2吸附剂种类、粒径、Ca/S比、接近饱和温度（即反应器温度-湿球温度）对SO_2去除率有较大影响。当接近饱和温度较小时，水在反应器中的蒸发速率变慢，溶解在水中的SO_2吸附剂与SO_2气体之间的快速反应起主要作用。当熟石灰作为SO_2吸附剂时，当Ca/S比大于1.2，饱和温度≤13K时，SO_2去除率可达95%以上。

To develop a new type of semi-dry flue gas desulfurization process, powder particle spouted bed (PPSB) was applied to low temperature desulfurization process. The coarse particles of average diameter of 400-1000mum were fluidized with gas involing 500-1500ppm SO_2 at the constant temperature of 120-200ﾟCThe slurry of SO_2 sorbent like slaked lime are continuously fed to the bed. SO_2 gas reacted with SO_2 sorbent in the reactor and the reacted sorbent was entrained from the reactor and collected by the bag filter.The effects of kind and size of SO_2 sorbent, approach to saturation temperature, Ca/S ratio reaction temperature and gas velocity on SO_2 removal were investigated.SO_2 removal was strongly affected by kind and size of SO_2 sorbent, Ca/S ratio, approach to saturation temperature, that is, the temperature of reactor- wet bulb temperature.If the approach to saturation temperature is small, the evaporation rate of water in the reactor becomes slow and very fast reaction between dissolved SO_2 sorbent in water and SO_2 gas plays main part of this reaction.When the slaked lime was used as SO_2 sorbent, more than 95% of SO_2 removal was obtained in the case where Ca/S ratio is larger than 1.2 and the approach to saturation temperature is smaller than 13K.