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

为开发一种新型的半干法烟气脱硫工艺，将粉末颗粒喷动床(PPSB)应用于低温烟气脱硫工艺。在120-200ﾟ的恒温下，用含500-1500 ppm SO_2的气体对平均直径400-1000微米的粗颗粒进行流态化，使SO_2脱硫剂如熟石灰的浆液连续进入床层。SO2气体在反应器中与SO2脱硫剂反应，反应后的脱硫剂被带出反应器，通过袋式过滤器收集。考察了脱硫剂种类和尺寸、接近饱和温度、Ca/S比、反应温度和气速对脱除SO2的影响。脱硫剂种类和尺寸、Ca/S比、接近饱和温度即反应器-湿球温度对脱硫率有很大影响。当接近饱和温度较小时，反应器内水的蒸发速率变慢，水中溶解的SO2脱硫剂与SO2气体发生很快的反应，以熟石灰为脱硫剂，在Ca/S比大于1.2，饱和温度小于13K的情况下，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.