Study On The Mechanism Of COS Formation In Desulfurization Using Iron Oxide Sorbent At Ambient Temperature

Coal gas desulfurization technology has become one of the key technologies of clean coal conversion and utilization. Because of its wide in temperature range, high in desulfurization efficiency, low chalking ratio for desulfurization sorbent, and other advantages, dry desulfurization technology has been widely applied to complex atmosphere, complex conditions, and different forms of sulfur fine desulfurization. Among them, the metal oxide adsorbent is considered to be the most potential coal gas purification desulfurization sorbent. Researchers and technicians who apply and research of iron oxide desulfurizer found the phenomenon of sulfur release. Sulfur releases are that outlet of sulfur more than that of inlet or form in outlet is different from that of inlet, such as carbonyl sulfide existed in outlet gas. Sulfur releases play a negative role in the downstream production, catalyst, and instrument, pipe and so on. However, there was few thorough research on this phenomenon, so the research on COS formation in desulfurization is very important.In this paper, combined with the main research content of National Natural Science Foundation (20976116) and Basic Research project of Shanxi Province (2009011010-2), iron oxide sorbent(TG) was selected to study. The method of nitrogen adsorption, XRD, SEM, XPS and infrared spectroscopy characterization methods were used to explore the various complexes parameter. H2S and CO2gas phase reaction to form COS and gas solid catalytic reaction to form COS in a fixed bed reactor were studied, results are as follows: ①Under the condition of water and without water, the effect of temperature and CO2concentration was researched.The results show that at ambient temperature,normal press, under CO2condition there was no COS formation.②Under the condition of water and without water,the effect of CO concentration、H2S concentration and space velocity on COS formation were researched. Results show that:The CO is carbon source of carbonyl sulfur formation in iron oxide desulfurization process; A certain amount of water are good for hydrogen sulfide removing and inhibiting carbonyl sulfur formation; The bigger the carbon monoxide concentration and hydrogen sulfide the higher the amount of carbonyl sulfide concentration; The higher of the temperature the higher concentration of carbonyl sulfide; The higher the space velocity the shorter of gas residence time,so it is bad for H2S adsorption and COS conversion.③Iron sulfide is catalysis on COS formation of CO reaction with H2S.④The load of sulfur on desulfurization sorbent has no effect on COS formation, the sulfur formed by regeneration is a catalyst of COS formation.⑤The catalytic mechanism of COS in desulfurization using iron oxide desulfurization sorbent at normal temperature was Put forward and the way of COS removal was given.