The Study On Modified Alumina Based Catalyst For High Concentration Carbonyl Sulfide Hydrolysis

Carbonyl sulfide, widely existing in the coal gas, petroleum and natural gas, is considered to be a serious poison to many catalysts used in the synthesis process, so it is necessary to remove COS from feed gas like hydrogen sulfide . The hydrolysis of COS with low concentration have been studied over the world, however only few technology is concentrated on the hydrolysis of high concentration COS till now.This study focuses on developing a novel catalyst for high concentration COS hydrolysis. A series of catalysts with different kalium oxide content , support component and pore-making agent is prepared. The activity and resisted-sulfide performance of COS hydrolysis are evaluated in a fixed bed reactor, characterized by using the technique such as TPD, FTIR, XRD etc.The evaluation result carried in fixed bed reactor showthat the initial activity and the adsorption rate of H2S are increased with the increasing of the kalium oxide content, however a overload can be lead to a sharply decreasing of activity at end of reaction. The most favorable content of kalium oxide in catalyst is 9.5%. The performance of resist-poision of catalyst can be significantly improved by adding titanium and the use of mixed pore-making agents. The conversion of the modified COS hydrolysis can exceed 95% at temperature 50℃ and space velocity 1000h~-1,with COS concentration 2500mgS/m3 and O2 content 12%.The TPD experienced result reveals that there are two kind of basic species on the surfaces of catalyst. One is independent of alkali content and transition metal wherea the another base species has a strong relationship with the concent of K2O . The surface base of catalyst has not change remarkablely when titanium is add. Compensation effect exists between activation energy and pre-exponential factor.XRD and FTIR characterization result indicated that there are sulfate on the surfaces of poisoned catalysts,and the amount of sulfate increase with the increasing of the content of alkali. No sulfate is found on the surface of modified catalyst.