基于电解海水的模拟船舶尾气湿法脱硝性能试验

Performance Test of Wet Denitration of Simulated Ship Exhaust Gas Based on Electrolyzed Seawater

采用电解海水法制备具有强氧化性的有效氯溶液,基于鼓泡反应器开展模拟船舶尾气湿法脱硝试验,分别研究了电解海水溶液初始pH值、有效氯浓度、用量及NO浓度和SO_2浓度等参数对脱硝性能的影响,并探讨相关反应机理。试验结果表明,电解溶液初始pH值的大小影响其氧化性的强弱;当电解溶液初始pH值为4～6时,电解溶液的ORP在1 000 mV以上,其氧化性较强,NO_X脱除率可达48%;当电解溶液初始pH值超过6时,其氧化性变弱,NO_X脱除率随着pH值的增大而急剧下降。随着电解溶液有效氯浓度和用量的增大,NO_X脱除率呈线性增大。NO浓度的增加有利于增大气液传质推动力,进而提高NO_X脱除率。SO_2浓度的变化对NO_X脱除率的影响较小。研究结果表明,电解海水溶液具有良好的脱硝效果,在船舶柴油机尾气脱硝方面有一定的应用潜力。

Available chlorine with strong oxidizability is prepared by using the method of seawater electrolysis,and the wet denitration test of simulated ship exhaust gas is conducted based on bubbling reactor. The effects of such parameters as the initial pH value, available chlorine concentration, dosage of the electrolyzed seawater and the NO concentration and SO2 concentration on the denitration performance are studied respectively. The related reaction mechanism is discussed. The test results show that the initial pH value of the electrolyte affects its oxidizing strength. When the initial pH value of the electrolyte is 4~6, the ORP of the electrolyte is above 1000 m V, the oxidative property is strong, and the NOX removal rate is up to 48%. When the electrolyte’s initial pH value is above 6, the oxidative property of the electrolyte becomes weak and the NOX removal rate decreases sharply as the pH value increases. The NOX removal rate increases linearly with the increase of the electrolyte’s available chlorine concentration and dosage. The increase of NO concentration is beneficial to increase the gas-liquid mass transfer force, and thereby increasing the NOX removal rate. SO2 concentration has little effect on NOX removal rate. The research results show that electrolyzed seawater has a good effect on denitration and has some application potential in the denitration of marine diesel engine exhaust gas.