石灰石-石膏湿法烟气脱硫过程的试验研究

Experimental Study of Limestone/Gypsum-based Wet Process Flue Gas Desulfuration

利用所建立的并流有序降膜式湿法脱硫装置,对石灰石-石膏湿法烟气脱硫过程进行了试验研究。试验结果表明:沿烟气行程上,脱硫率上升趋势逐步减弱,脱硫率较高时,再提高脱硫率,吸收段高度或液气比要大幅增加,火电厂机组在确定脱硫系统脱硫率时,应有适当选择;脱硫浆液pH值下降,且在吸收塔入口至0.5 m范围内,浆液pH值下降迅速,而后下降变缓;浆液中石灰石含量下降趋势逐步增强;同时浆液中Ca2+、六价硫S6+及四价硫S4+浓度均增加,Ca2+、S6+浓度增加使得石膏过饱和度有所增加。

By making use of a parallel-flow orderly falling film type of wet process desulfuration device established by the authors,an experimental study has been conducted of limestone/gypsum-based wet flue gas desulfuration process.The test results show that along the flue gas path,the rising trend of the desulfuration rate gradually weakened.When the desulfuration rate is comparatively high,to further raise the desulfuration rate will require an increase of the absorption section height or the liquid-gas ratio by a large margin.When the desulfuration rate of a boiler unit in a thermal power plant is to be determined,a proper choice must be made.The pH value of the desulfuration slurry decreases and there will be a rapid reduction of the pH value of the desulfuration slurry in an area from the inlet of the absorption tower extending to 0.5 m distance followed by a slower pH value reduction.The reduction trend of the limestone content in the slurry should be gradually intensified.In the meantime the concentration of Ca2+,S6+ and S4+ will be all enhanced.The increase of Ca2+ and S6+ concentration will somewhat increase the supersaturation of the gypsum.