The Fine Removal Of H₂S By Activated Carbon Modified By Loading CuO

There are many ammonia and methanol synthesis plants using coal as feedstock in China. In particular, some large-scale chemical fertilizers use coal to replace oil as feedstock lately. Sulfur compounds contained in syngas derived from coal can easily poison the activities of synthesis catalysts. With the development of advanced synthesis catalysts and new processes, it is demanded that the H2S content in syngas isn't more than 0.05ppm.Active carbon is an absorbent with large in surface area ,complex in pore structure, and rich in surface active group as well as simple in application, which is used as desulfurizer. But, while the common active carbon was used in fine desulfurization, its sulfur removal capacity is very low. Therefore, the research of modifying active carbon play an important role in improving fine desulfurization.In this paper, two sorts of activated carbons (originating from coal), columnar and granular, were used as raw material. They are modified by two activation methods of high-pressurehydrothermal and loading CuO, thus fine desulfurizers were prepared. The influences of preparation conditions including hydrothermal activation pressure , the charge amount, the calcination temperature and the technological conditions including the desulfurization temperature, oxygen atmosphere on fine desulfurization on activated carbons were evaluated in a fixed-bed reactor. The properties of the activated carbons before and after fine desulfurization were characterized by nitrogen adsorption at low temperature, TGA, DTA, XRD methods.The conclusions obtained from experimental results are as follow:1. High-pressure hydrothermal activation improves the desulfurization activities of granular activated carbon, but for columnar activated carbon the reverse result is obtained. The reason may be that high-pressure hydrothermal has the action of enlargeing pore and causes the increase of micropore diameter.2. The loading CuO on active carbon greatly increase the breakthrough sulfur capacity of both granular activated carbon and columnar activated carbon. The optimal charge amount for CuO is 4% wt. CuO play an important role in catalytic and adsorption removal H2S.3. The technological temperature slightly change the desulfurization activities of activated carbon in the rang of experimental temperature.4. The existence of O2 in syngas also increases thebreakthrough sulfur capacity of desulfurizer. 5. The specific surface area isn't critical factor determining the breakthrough capacity of the desulfurizer.