Experimental study of selective non-catalytic reduction process with methylamine as reducing agent

doi:10.11949/j.issn.0438-1157.20171687

Abstract

Abstract:

Selective non-catalytic reduction (SNCR) denitration efficiency is lower than the minimum designed requirement when the boiler is operating under low load. To improve the characteristics of such working conditions, the feature of selective non-catalytic reduction denitration with methylamine as reductants is studied and the reaction mechanism is analyzed in the tube furnace reaction system. The effect of oxygen content, NSR, initial concentration of NO, SO₂ and water content on the denitrification properties of methylamine SNCR is discussed. The results show that:the relationship between denitration efficiency and temperature is bimodal, the inflection point temperature is 750℃, and the best temperature window for practical industrial application is 450-600℃. The NO reduction efficiency was increased with the increase of NSR, and the concentration of NO₂ and N₂O was also augmented. The maximum NO removal efficiency was 85.0%. The oxygen content has dual characteristics to SNCR denitrification reaction, the efficiency of NO reduction is the greatest under the condition of 3% oxygen content. The increase of the initial concentration of NO makes the material concentration of the simulated flue gas increase, the NO reduction efficiency and the by-product increase. The higher concentration of SO₂, the greater the reduction of NO reduction efficiency. The increase of water content was beneficial to the denitrification reaction. The experimental conclusion of methylamine SNCR denitrification in this paper is helpful to the application of selective non-catalytic reduction process with methylamine as reducing agent to industrial furnace and to optimize the denitrification characteristics of the boiler at low load operation.

Key words: methylamine, NO reduction, SNCR, nitrogen oxide, control factors

摘要：

为改善工业窑炉以及锅炉低负荷运行工况下的脱硝特性，本文对甲胺作还原剂的选择性非催化还原（SNCR）脱硝特性进行了实验研究，探讨了各控制因素对脱硝特性的影响以及分析了反应机理。实验结果表明：脱硝效率随反应温度呈双峰特性，拐点温度为750℃，最佳温度窗口为450～600℃；脱硝效率随氨氮比（NSR）增大而升高，反应产生的副产物NO₂和N₂O浓度随之增大；氧含量对SNCR脱硝特性具有双重特性，高浓度和低浓度氧气均对脱硝反应不利；物料浓度随NO初始浓度增加而增大，脱硝效率和副产物也提高； SO₂浓度越高，脱硝效率下降越多；水汽含量增大，脱硝效率也随之增大。本文的实验结论有助于SNCR脱硝工艺应用于工业窑炉以及优化锅炉低负荷运行时的脱硝特性。

关键词: 甲胺, 脱硝, 选择性非催化还原, 氮氧化物, 控制因素

CLC Number:

PU Ge, DU Jiantai, ZHANG Zhang, ZHANG Dinghai, WU Bang, HUANG Beibei, ZHU Tuanhui. Experimental study of selective non-catalytic reduction process with methylamine as reducing agent[J]. CIESC Journal, 2018, 69(7): 3234-3241.

蒲舸, 杜建太, 张章, 张定海, 吴棒, 黄蓓蓓, 朱团辉. 甲胺作还原剂的选择性非催化还原脱硝特性的实验研究[J]. 化工学报, 2018, 69(7): 3234-3241.

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