Removal Of Low Concentration COS From N₂ By Adsorption

Pure carbonyl sulfide (COS) is an organicacidity gas without odor and color. Its acidity and polarity are weak in H2S. Molecules are linear molecular structure. COS widely exists in many industrial gases which include natural gas, liquefied petroleum gas, coke oven gas and water gas. Because the materials and processes are different, the content also varies. Although its concentration is lower, it can't be removed easily. Removing low concentration COS is key to realize fine desufurization if reducing the total sulfur of industrial gases and food-grade CO2. Thus, to remove low concentration COS is an important issue.On the basis of background of this paper, four aspects about how to remove low concentration COS have been studied. The main contents were listed as follows:1. A study of removal of low concentration COS by using modified ACF with alkaliThe activated carbon fibres were modified with some alkali such as NaOH,KOH,Na2CO3,K2CO3 by the impregnation method. Some factors which maybe affect the performance of removing carbonyl sulfide such as the kinds and the concentration of alkali, the adsorption temperature and the components of feed gas were investigated on the fixed-bed reactor. It was showed that the activated carbon fibres modified with 15%KOH had a higher breakthrough sulfur capacity than the others. The best adsorption temperature is 40℃. CO2 in feed gas decreased the COS adsorption capacity due to competition adsorption.2. A study of removal of low concentration COS by using modified SBA-15 with PEIThe SBA-15 were modified with PEI by the impregnation method and some factors which maybe affect the performance of removing COS such as the kinds and the concentration, the temperature of reaction, size of adsorbent and the components of feed gas were investigated on the fixed-bed reactor. It was showed that the 50%PEI modified SBA-15 had a higher sulfur capacity than others at room temperature. The best adsorption temperature is 60℃. When the size of adsorbent was 60-80 mesh, the desulfurization had a better effect. The result showed that chemical adsorption and physical adsorption occurred. CO2 in feed gas tremendously decreased the COS adsorption capacity due to competition adsorption. And the mechanism of removal carbonyl sulfide with PEI/SBA-15 was deduced.3. A study of removal of low concentration COS by using modified SBA-15 with transitional metalsThe SBA-15 were modified with transitional metals such as Zn,Fe,Co,Ni,Cu and Ag by the impregnation method and some factors which maybe affect the performance of removing COS such as the kinds and the concentration, the temperature of asdorption and the components of feed gas were investigated on the fixed-bed reactor. It was showed that the 40%Ag modified SBA-15 had a higher sulfur capacity than others at room temperature. The best adsorption temperature is 40℃. CO2 in feed gas greatly decreased the COS adsorption capacity due to competition adsorption.4. A study of regeneration method for sorbent using removing low concentration COSSorbent used to remove low concentration COS were regenerated with gas method. The experiment showed that ACF modified with some alkalis can not regeneration and 50% wtPEI/SBA-15 can regeneration. But the sulfur capacity of the sorbent is far away initial value. SBA-15 modified with 40%Ag had a bad regeneration.