DEVELOPMENT OF A NOVEL TECHNOLOGY FOR AIR POLLUTION CONTROL BY USING ELECTROSPRAY METHOD

在本研究中，我们提出了一种新的脱硝技术，利用电喷雾法产生的微细水滴。第一种是在低温下通过雾化苯酚和/或氨溶液来增强热脱硝反应。我们得到了以下结果。(1)在较低温度范围内（650-750 ℃），氨与苯酚共存时，NO的还原反应进行得很顺利，而在较高温度范围内（750-850 ℃），NO的还原反应受到抑制。(2)通过电喷雾法以液滴形式注入苯酚/氨水溶液，证实了NO还原的显著提高。在NO 388 ppm、O_24%，NH_3400ppm、苯酚102 ppm、H_2O6.4%，N_2余量、停留时间1.5- 1.8秒的条件下，650 ℃时，NO的还原率约为30%（是预蒸发溶液的两倍），700 ℃时，NO的还原率约为50%。(3)通过对出口气体中CO、CO_2含量的测定，发现在600-650 ℃的低温下，CO的含量较高，说明在反应器中加入雾化液可以有效地分解苯酚。其次，考察了雾化液滴进入电晕放电反应器对NOx还原的影响，得到以下结果：(1)通过将细小水滴雾化到放电等离子体中，提高了NOx的去除效率。(2)减小电晕放电中喷射的液滴平均直径，可以提高脱硝效率。特别是，我们获得了最大的脱硝效率，通过使用喷雾器。(3)研究了pH值对脱硝效率的影响。在pH 5.0左右，脱硝效率均有所提高。(4)H_2O_2的加入提高了NOx的还原率。H_2O_2对NO的还原量是水滴的1.5倍。(5)该技术所需水量比传统的湿法脱硝工艺少约1/100。

In this study, we proposed the novel De-NOx technologies by using the fine water droplets which produced by electrospray method. First one is the enhancement of thermal De-NOx reaction at low temperature by atomization of phenol and/or ammonia solution. We obtained the following results.(1) By coexisting ammonia with phenol aqueous solution, reduction of NO was proceeded at the range of lower temperature, 650-750ﾟC,but was restrained at the range of higher temperature, 750-850ﾟC.(2) By injecting phenol/ammonia aqueous solution as droplet by electrospray method, the markedly improvement of NO reduction was confirmed. About 30% of nitrogen monoxide was reduced at 650ﾟC (twice as much as the case of pre-vaporized solution), and about 50% at 700ﾟC in the following condition, NO 388ppm, O2 4%, NH_3400ppm, phenol 102ppm, H_2O6.4%, N_2 balance, residence time 1.5-1.8sec.(3) As a result of the measurement of CO,CO_2 in outlet gas, we could see more CO concentration at low temperature, 600-650ﾟC.So phenol seems to be decomposed by adding sprayd solutions.Second, the effects of the atomization of droplets into corona discharge reactor on the NOx reduction were examined and have obtained the following results.(1) The efficiency of NOx removal was improved via atomization of fine water droplets into the discharge plasma.(2) Decreasing the mean diameter of droplets, which were injected in the corona discharge, the De-NOx efficiency improved. Especially, we obtained the maximum De-NOx efficiency by using nebulizer.(3) The effect of pH on the De-NOx efficiency was investigated. The efficiency of De-NOx was improved both side of pH5.0.(4) NOx reduction was improved by the addition of H_2O_2. The amount of NO reduction was in the case of H_2O_2 was 1.5 times that of water droplets.(5) The necessary amount of water of this technology are less than that of conventional wet De-NOx process by a factor of about 1/100.