应用蒸汽相变协同脱除细颗粒和湿法脱硫的实验研究

Experimental Study on Combined Wet Flue Gas Desulfurization and Removal of Fine Particles by Heterogeneous Condensation Enlargement

在湿法烟气脱硫(wet flue gas desulfurization,WFGD)系统中进行了利用蒸汽相变原理协同脱除细颗粒的试验研究:通过添加蒸汽建立旋流板脱硫塔内蒸汽相变所需的过饱和水汽环境,利用过饱和水汽,以细颗粒为凝结核发生相变,促进细颗粒凝结长大并由脱硫液、除雾器高效脱除;研究采用Ca(OH)2、NaOH、Na2CO3、NH3·H2O等4种不同脱硫剂时,WFGD系统对细颗粒的脱除性能,并考察了脱硫剂种类、液气比、蒸汽添加量等对细颗粒脱除效果的影响。结果表明,采用NaOH、Na2CO3作为脱硫剂对细颗粒的脱除效果明显优于Ca(OH)2和NH3·H2O;在脱硫塔进口烟气、塔内脱硫液进口上方添加蒸汽,建立过饱和水汽环境,可使细颗粒脱除效率显著增加;液气比的影响与脱硫塔内是否存在蒸汽相变有关。

A novel process to remove fine particles and SO2 from coal combustion simultaneously by heterogeneous condensation enlargement using wet flue gas desulfurization （WFGD） system was presented. The supersaturated environment was established for heterogeneous condensation by adding water vapor in the inlet flue gas or above the liquid phase inlet in desulfurization tower. Fine particles grow in size by vapor heterogeneous condensation with the particles acting as nucleation centers, then the grown particles are removed efficiently by desulfurizer and demister. The fine particles removal performance, the influences of desulfurizer species, liquid-gas ratio and the addition amount of water vapor were investigated. The results show that removal efficiency of fine particles by NaOH, Na2CO3 desulfurizer is superior to Ca（OH）2 and NH3.H2O. Additionally, the removal efficiency increases observably with the addition of water vapor. The influence of liquid-gas ratio is related to whether the existence of heterogeneous condensation in the desulfurization tower.