燃煤电厂干化灰渣中氯的脱除研究

Research on dechlorination from dry ash of coal-fired power plants

干化灰渣是燃煤电厂脱硫废水零排放的固态废弃物,但由于氯含量高限制其资源化利用。再加之脱硫废水零排放技术渐成主流,研究干化灰渣高效脱氯的方法具有重要的现实意义。通过XRF和XRD对干化灰渣进行元素成分和物相表征,通过IR分析灰渣的结构特性,采用添加脱氯剂三氧化二铝(质量分数为2.5%~10.0%)并结合高温煅烧(600~900℃)研究了干化灰渣中氯去除过程。得到的优化工艺参数为:煅烧温度为700℃、煅烧时间为2 h、三氧化二铝添加量为7.5%,优化工艺下脱氯率可达96.9%。并对脱氯剂三氧化二铝的作用机理作了初步分析。

Dry ash is a solid waste with zero discharge of desulphurization wastewater from coal-fired power plants,but its resource utilization is limited because of high content of chlorine.In addition,the zero-discharge technology of desulphurization wastewater has gradually become the mainstream.It is of great practical significance to study the efficient dechlorination method for dry ash.The element composition,crystal phase and structure of dry ash were characterized by XRF,XRD and IR.The process of chlorine removal in dry ash was studied by adding dechlorination agent Al2O3(mass fraction of 2.5%~10.0%)and combining with calcination method(600~900℃).The optimized process parameters were as follows:calcination temperature of 700℃,calcination time of 2 h,and Al2O3 addition amount of 7.5%.Under the optimized process,the dechlorination rate could reach 96.9%.And the preliminary mechanism of dechlorination agent Al2O3 was analyzed.