湿法脱硫系统中二水硫酸钙结晶特性分析

STUDY ON CRYSTALLINE PROPERTIES OF CALCIUM SULFATE DIHYDRATE IN WET DESULFURIZATION SYSTEM

为解决脱硫塔内部结垢问题,通过探究系统温度、pH值、过饱和度对二水硫酸钙结晶诱导时间的影响,以及不同过饱和度下Cl^-、Na^+和Mg^(2+)对晶体诱导时间、抑制效率、表面能和成核率的影响来表征结晶成垢的趋势。结果表明:温度和过饱和度升高均会显著缩短二水硫酸钙结晶诱导时间,而pH值的影响相对较小;添加Mg^(2+)、Cl^-、Na^+可以延长结晶诱导时间、增大晶体表面能并缩小晶体成核速率,且均对二水硫酸钙的结晶起到抑制作用,抑制强度遵循Mg^(2+)>Cl^->Na^+的规律。

To solve the problem of scaling inside desulphurization towers,scaling-tendency was explored through studying the effects of temperature,pH value and supersaturation on the induction time of crystal as well as the effects of chloride ions,sodium ions and magnesium ions on induction time,inhibition efficiency,surface energy and nucleation rate. The results showed that the increase of temperature and supersaturation could shorten the induction time significantly,while pH value had relatively lower effect. The addition of Mg^2+,Cl^-and Na^+could prolong the induction time,increase the surface energy and reduce the crystal nucleation rate,which inhibited the crystallization of calcium sulfate dihydrate,and the inhibition intensity followed the order of Mg^2+>Cl^->Na^+.