研究报告
叶小莉,吴晓琴,王淑娟.氨水/FeⅡEDTA溶液同时脱硫脱硝实验研究[J].环境科学学报,2014,34(6):1560-1566
氨水/FeⅡEDTA溶液同时脱硫脱硝实验研究
- Simultaneous desulfurization and denitration of sintering flue gas using ammonia/FeⅡEDTA solution
- 基金项目:国家高技术研究发展(863)计划(No.2012AA062501)
- 叶小莉
- 武汉科技大学化学工程与技术学院, 武汉 430081
- 吴晓琴
- 武汉科技大学化学工程与技术学院, 武汉 430081
- 王淑娟
- 武汉科技大学化学工程与技术学院, 武汉 430081
- 摘要:在间歇鼓泡反应器中,采用FeⅡEDTA复配氨水对协同吸收SO2和NO进行了研究,研究过程中考察了NH3-NH4+的浓度、吸收液温度、初始pH值、络合剂浓度及种类对SO2和NO吸收效果的影响.结果表明,当NH3-NH4+的浓度小于2.1412 mol·L-1时,NO的脱除率随着NH3-NH4+浓度的增加而增大,当NH3-NH4+的浓度大于2.1412 mol·L-1以后,由于过多的硫酸根的影响,对NO的吸收有抑制作用;温度的升高不利于SO2和NO的吸收;随着pH值由小到大的变化,FeⅡEDTA在液相中的组成形态发生改变,其络合能力在pH为6.5时达到最大值;络合剂浓度增加,脱硝率随之增加.当FeⅡEDTA浓度增加到0.03 mol·L-1以后,脱硝率的增长趋势随着络合剂浓度的增大变缓;与氯化钴、高锰酸钾、三乙醇胺、尿素和氨水复配后的溶液吸收NO过程相比较,FeⅡEDTA络合剂对NO的脱除率明显高于其他添加剂,是最佳的氨水复配络合吸收剂.根据实验结果,本系统中最佳协同脱除SO2和NO的工艺条件为:NH3-NH4+浓度为2.1412 mol·L-1,吸收温度为50℃,pH为6.5和FeⅡEDTA浓度为0.03 mol·L-1.
- Abstract:This paper studied simultaneous desulfurization and denitration by ammonia containing FeⅡEDTA in a batch bubbling-absorber. The factors, such as concentration of NH3-NH4+, temperature of aqueous absorbent, initial pH value, FeⅡEDTA and other complexants with different concentrations, were investigated. Experimental results showed that desulfurization capacity of aqueous absorbent increased significantly with the increase of NH3-NH4+ concentration when NH3-NH4+ concentration was less than 2.1412 mol·L-1. When NH3-NH4+ concentration was more than 2.1412 mol·L-1, the desulfurization capacity didn't change markedly, and the efficiency of denitration was restrained by more SO42- ions in solution. Higher temperature is not favorable to simultaneous desulfurization and denitration because the reactions of defulsurization and denitration are exothermal. The complexation capacity of FeⅡEDTA reached the maximum point at pH value of 6.5. The efficiency of denitration increased with the increasing FeⅡEDTA concentration until 0.03 mol·L-1, and then the efficiency of denitration increased slowly. Denitration efficiency of FeⅡEDTA was 20 percent higher than those of cobalt chloride, potassium permanganate, triethanolamine and urea, therefore was selected as the optimum complexant mixed with ammomia solution. According to experimental results, the optimum factors of the system for simultaneous desulufurization and denitration by ammonia solution mixed with FeⅡEDTA were the concentration of NH3-NH4+ of 2.1412 mol·L-1, aqueous absorbent temperature of 50℃, initial pH value of 6.5, and FeⅡEDTA concentration of 0.03 mol·L-1.
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