针对氨/尿素溶液湿法同时脱硫脱硝工艺在工业应用中存在脱硝效率不高的问题,在鼓泡吸收反应器中采用不同的吸收剂和添加剂,考察了不同操作条件下湿法同时脱硫脱硝特性,并对吸收反应后溶液中的离子浓度和pH值进行了分析与研究.研究发现:在尿素/铵根溶液脱硫脱硝过程中,溶于液相中的氧对NO具有一定的氧化作用,而NO气相氧化是脱硝的主要作用机制；O2的存在是添加剂起催化作用的必要条件,SO2的存在对NO的吸收起到了协同促效作用.实验研究还发现,不同的添加剂对脱硫脱硝的作用机制和效果不同,醇胺类添加剂具有缓冲和催化作用,且混合醇胺的效果更好,而高锰酸钾作添加剂时,脱硫和脱硝过程是相互竞争的.实验中尿素溶液的脱硝效率最高,而单一氨水溶液的脱硝效率最低；尿素能抑制亚硝酸分解生成NO,碳酸氢铵的加入使得吸收液的pH值下降明显,不利于氮氧化物的脱除.%The ammonia/urea solution wet desulfurization and denitrification technology has low denitration efficiency in industrial application. In this study, the performance of simultaneous removal of SO2 and NOX by the aqueous urea/ammonium ion/additive solution in a bubbling reactor was investigated, and the ions concentration and pH values of the solution after absorption was analyzed. The results show that the oxidation of NO by O2 in the gas phase is the dominant mechanism of Nox removal by the aqueous urea/ammonium ion solution. The additive has no catalytic effect on NO absorption without the presence of O2, and the presence of SO2 promotes the NO absorption. The experimental results indicate that the reaction mechanism and the effect concerning NO removal by various additives are different. The alkanolamines additive has buffer and catalytic effects, and the mixing alkanolamines additive works better. However, the SO2 absorption is in competition with the NO removal in the aqueous urea solution with KMnO4. Under the experimental condition, the NO removal efficiency is lowest in the ammonia/water solution, and highest in the urea solution. The urea could prevent the nitrous acid from decomposing into NO, and the pH of the absorption solution decreases obviously while adding ammonium bicarbonate, which is unfavourable to Nox removal.
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