延缓烟气洗涤废水预处理过程硫酸钙结垢的工艺研究及实践

Study on Delaying Calcium Sulfate Scaling in the Pretreatment of Flue Gas Washing Wastewater

烟气洗涤废水预处理过程会产生大量硫酸钙结晶析出,影响设备正常运行和连续化生产。本文研究了几种不同试剂组合方案中硫酸钙的结晶行为,并就强化沉淀过程进行了探索,考察了反应温度、搅拌速度、二次强化沉淀等对硫酸钙结晶的影响。综合研究结果,确定了采用碳酸钠强化沉淀法打破硫酸钙溶解-结晶平衡,实现了维持预处理过程硫酸钙的浓度低于饱和浓度及减少其在压滤机及管道中结垢的目标。与此同时优化了试剂方案,大幅降低了试剂成本。

The pretreatment process of flue gas washing wastewater produced a large amount of calcium sulfate crystallization,which affected the normal operation and continuous production of the equipment.The crystallization behavior of calcium sulfate in several different reagent combinations was studied,and the enhanced precipitation process was explored.The effects of reaction temperature,stirring speed and secondary enhanced precipitation on the crystallization of calcium sulfate were investigated.Based on the comprehensive research results,it was determined that the sodium carbonate enhanced precipitation method was used to break the dissolution crystallization balance of calcium sulfate,achieve the goal of maintaining the concentration of calcium sulfate below saturation in the pretreatment process and reducing its scaling in the filter press and pipeline.Meanwhile,the reagent scheme was optimized and the reagent cost was greatly reduced.