煤气发电厂湿法脱硫废水工艺优化

Study on Process Optimization of Wet Desulfurization Wastewater in Gas Power Plant

以某超高温亚临界煤气发电湿法脱硫废水处理项目为例,对该项目脱硫废水采用三联箱化学沉淀法,进行pH值、助凝剂、污泥产量工艺条件优化试验。结果表明,随着石灰乳投加量增加,中和箱废水pH值逐渐增大,废水电导率逐渐降低。石灰乳溶液投加量为24 g/L时,脱硫废水中Mg^(2+)、SO_(4)^(2-)离子浓度大幅减少,而Ca^(2+)离子浓度有所增加,超出国家标准要求。为了去除Ca^(2+)离子,添加碳酸钠溶液,碳酸钠最佳投加量为6.9 g/L;非离子型助凝剂处理脱硫废水的效果优于阴离子型和阳离子型助凝剂;污泥产量随脱硫废水pH值增加而提高,pH值为11时,污泥产量达到最大值,污泥主要成分为CaSO_(4)·2H_(2)O、Mg(OH)_(2)、Ca(OH)_(2)。

Taking a wet desulfurization wastewater treatment project of ultra-high temperature subcritical gas power generation as an example,the desulfurization wastewater of this project was treated by triple-box chemical precipitation method,and the process conditions of pH value,coagulant aid and sludge production were optimized.The results showed that with the increase of lime milk dosage,the pH value of neutralization tank wastewater increased gradually,and the conductivity of wastewater decreased gradually.When the dosage of lime milk solution was 24 g/L,the concentration of Ca^(2+)and SO_(4)^(2-) ions in the desulfurization wastewater decreased significantly,while the concentration of Ca^(2+) ions increased,which exceeded the national standard requirements.In order to remove Ca^(2+) ions,sodium carbonate solution was added,and the optimum dosage of sodium carbonate was 6.9 g/L;the flocculation effect of non-ionic coagulant aid in the treatment of desulfurization wastewater is better than that of anionic and cationic coagulant aid.The sludge yield increased with the increase of pH value of desulfurization wastewater.When the pH value was 11,the sludge yield reached the maximum.The main components of the sludge were CaSO_(4)·2H_(2)O,Mg(OH)_(2) and Ca(OH)_(2).