铁锰系脱硫剂对煤气中羰基硫的脱硫机理初探

The desulfurization mechanism of iron-manganese compound oxide desulfurizer for removal of COS from coal gas

采用气相质谱、XRD，SEM，EDS等多种分析方法对脱硫剂、气氛及出口气成分等进行分析，在240～400℃、常压及空速为500～2000h^-1的条件下，制备的脱硫剂对羰基硫脱除效果较好、从脱硫剂还原-吸附-脱硫过程的分析，推断脱硫剂的反应历程是羰基硫在还原性气氛下首先被加氢转化成硫化氢气体，之后硫化氢分子吸附在脱硫剂表面，并与脱硫剂中活性组分发生反应，转化为金属硫化物和水的过程．在无含碳氧化物气氛中，脱硫剂的脱硫净化度高，优于添加含碳氧化物气氛．碳氧化物的存在抑制了羰基硫加氢和水解两反应向正方向进行，导致COS出口浓度的增加，表明羰基硫在反应体系中以化学转化为主，即羰基硫优先在脱硫剂的活性中心作用下，进行加氢反应生成H2S，进而被吸收.

The sorbent, atmosphere and components of outlet gas were analyzed by mass spectra, XRD, SEM, EDS etc. Desulfurization performance of sorbents is commendable at 240 - 400 ℃, atmospheric pressure and space speed of 500 - 2 000 h^-1 The possible mechanism of desulfurization reactions was obtained by analyzing the reduction-adsorption-sulfidation process. COS was converted to H2S by hydrogen in strongly reducing atmosphere firstly. Then H2S was adsorbed on the surface of desulfurizers, reacted with active components, and transformed metal sulfides and water. At the atmosphere without carbonaceous oxide, efficiency of removal of carbonyl sulfur is better than that of the atmosphere with carbonaceous oxide in test conditions. The existence of carbonaceous oxide restrains hydrogenation and hydrolytic process of COS, which leads to a higher concentration of COS in outlet. It shows that chemical conversion is the main partway in reaction system of COS. It indicates that hydrogenation conversion is the main reaction of COS removal from syngas. COS is preferentially catalyzed with active components in desulfurization sorbents, and generates H2S which is absorbed whereafter.