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

为开发新型半干法烟气脱硫工艺，将粉末颗粒喷动床（PPSB）应用于低温脱硫工艺。平均粒径为400- 1000 μ m的粗颗粒，在120-200 ℃恒温条件下，与含SO_2量为500- 1500 ppm的气体一起流化。研究了SO2吸收剂的种类和粒径、接近饱和温度、Ca/S比、反应温度和气速等因素对脱硫效果的影响，结果表明，SO2吸收剂的种类和粒径、Ca/S比、接近饱和温度、反应温度和气速等因素对脱硫效果影响较大，接近饱和温度，即反应器的温度-湿球温度。如果接近饱和温度很小，反应器中水的蒸发速率变慢，溶解在水中的SO_2吸收剂与SO_2气体之间的快速反应是这一反应的主要部分，当使用消石灰作为SO_2吸收剂时，当Ca/S比大于1.2，接近饱和温度小于13 K时，脱硫率可达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.