碳酸钠和过硫酸铵对砷中毒脱硝催化剂清洗再生效果对比  

Comparison of effects of ammonium peroxydisulfate and sodium carbonate on regeneration of arsenic poisoned catalysts

作　　者：范美玲[1] 杨晓博[1] 赵长多 李晓刚[2] 许兆鹏[2] 孙希德 崔立业 夏启斌[1] 

机构地区：[1]华南理工大学化学与化工学院,广东广州510640 [2]吉林电力股份有限公司科技开发分公司,吉林长春130021

出　　处：《热力发电》2017年第9期112-116,共5页Thermal Power Generation

基　　金：广东省科技计划项目(2011B010100030);江苏省金坛市科技支撑计划(工业)重点项目(JT2014038)~~

摘　　要：选择性催化还原(SCR)烟气脱硝工艺中,砷中毒是脱硝催化剂失活的主要原因之一,且脱硝催化剂难以清洗再生。对此,本文以砷中毒脱硝催化剂为研究对象,研究催化剂表面砷的价态和含量对催化剂活性的影响;并分别采用1.0 mol/L碳酸钠和1.0 mol/L过硫酸铵对其进行再生。结果表明:砷中毒脱硝催化剂表面砷元素主要以As^(5+)形式存在,其含量对催化活性有显著影响,当催化剂表面的As/V质量比由2.04增大至3.52时,脱硝效率降低15.71%;碳酸钠和过硫酸铵对砷中毒脱硝催化剂的清洗再生效果有明显差异,对砷的去除率分别为66.0%和25.3%,表明碳酸钠具有更好的除砷效果;碳酸钠可与砷生成易溶于水的砷酸钠,从而降低了砷中毒脱硝催化剂表面的砷含量,恢复催化剂活性。Arsenic poisoning is an important reason for deactivation of selective catalytic reduction （SCR） catalysts during SCR denitration process. Once the catalyst is poisoned by arsenic, it is difficult to regenerate by common washing methods. To solve this problem, this article investigates the influence of valence state and content of arsenic on activity of the SCR catalysts, by taking the arsenic poisoned catalysts as the research object. Moreover, the deactivated catalysts were washed and regenerated by ammonium peroxydisulfate with concentration of 1.0 mol/L and sodium carbonate with concentration of 1.0 mol/L. The results show that, the arsenic species mainly exist in valence state ofpentavalent （As5＋） on the arsenic poisoned catalysts＇ surface, and the content of As has a significant effect on the catalytic denitrification activity. Importantly, as the mass ratio of As to V was increased from 2.04 to 3.52, the denitrification efficiency decreased by 15.71%. Besides, the removal rate of As was 66.0% when washed by Na2CO3 aqueous, while that of the ammonium peroxydisulfate was merely 25.3%. The reason was probably that arsenic on the catalyst surface could convert into Na3AsO4, which was removed easily due to its well solubility in H2O. Consequently, the catalytic denitrification efficiency recovered.

关 键 词：烟气脱硝 砷中毒 SCR 催化剂 再生 过硫酸铵 碳酸钠 催化活性 脱硝效率 

分 类 号：X505[环境科学与工程—环境工程]