常温条件下O2和NO2对Ca(OH)2吸附SO2产物的影响

INFLUENCE OF O2 AND NO2 ON ADSORPTION PRODUCTS OF SO2 BY Ca(OH)2 AT LOW TEMPERATURE

在100℃的无水蒸气条件下研究以Ca(OH)2为吸收剂同时脱硫脱硝过程中SO2的固定和氧化过程,以及O2和NO2的作用。分别用原位漫反射傅里叶红外光谱和固定床反应器,研究过程中Ca(OH)2表面和气相的成分变化。结果表明:SO2吸附在Ca(OH)2表面形成的CaSO3不易被O2氧化,但可以被NO2氧化。同时脱除过程中,NO2对CaSO3的氧化具有选择性:930~936 cm^-1位置的红外吸收峰在反应过程中先升高后降低,980~995 cm^-1位置的红外吸收峰只升高不降低。无O2条件下,参与反应的NO2以接近1∶1的比例转化为NO,而有O2条件下Ca(OH)2同时脱除NO2和SO2时,Ca(NO3)2的含量明显增加,且反应前期CaSO4的生成速率加快。

In order to analyze the fixation and oxidation reaction of SO2 in simultaneous removal of SO2 and NO x by Ca(OH)2,and the influence of O2 and NO2 on this progress,DRIFTS(diffuse reflectance infrared Fourier transform spectrometry)and fixed bed reactor were used respectively for composition changes of solid and gas phase at 100℃ and 0% RH.The results showed that firstly SO2 was rapidly adsorbed on Ca(OH)2 to form CaSO3,which could hardly be oxidized by O2,but could be oxidized to CaSO4 by NO2.CaSO3 showed selectivity during simultaneous removal process,of which the infrared absorption peak at the position of 930~936 cm^-1 first increased and then decreased,while the peak at 980~995 cm^-1 monotonically increased.When SO2 and O2 coexisted in the gas,it could react with Ca(OH)2 to form CaSO4.When NO2 and SO2 were simultaneously removed by Ca(OH)2 in the absence of O2,the ratio of produced NO/consumed NO2 was around 1∶1,but in the presence of O2,the content of Ca(NO3)2 increased significantly,and the formation rate of CaSO4 was accelarated in the early stage of reation.