Study Of Preparation Of Moderate Temperature Carbonyl Sulfide Hydrolysis Catalysts And Their Hydrolysis And Deoxidation Performance

Compared with oil resources,there are more abundant coal resources,so it is particularly important to use coal resources scientifically and rationally.In coal,there is a large amount of sulfur-containing substances,and a large amount of sulfur-containing gas is generated in the use of coal.These gases will not only cause environmental pollution,but also lead to corrosion of equipment pipelines and inactivation catalysts in subsequent sections.Therefore,it is necessary to remove the sulfur-containing components from the gas,and one of the most important pathways for the desulfurization is carbonyl sulfide hydrolysis.Under moderate temperature conditions,traditional carbonyl sulfide hydrolysis catalysts are more prone to oxygen poisoning and the activity of the catalyst is reduced.Therefore,it is particularly important to develop a moderate-temperature carbonyl sulfur hydrolysis catalyst with the ability to resist poisoning.Oxygen poisoning of carbonyl sulfide hydrolysis catalyst is caused by a small amount of oxygen in the reaction system.In order to solve the problems caused by oxygen,it is considered to add a deoxidizing component in the catalyst so that the catalyst has the ability to remove oxygen in the system.This avoids oxygen poisoning of the catalyst.The molybdenum-based deoxidizer has the ability to withstand sulfur and deoxidize,and the hydrogen contained in the raw gas can provide the basis for the deoxidation of the molybdenum-based deoxidizer.In this paper,the law of hydrolysis activity of carbonyl sulfide hydrolysis catalysts with different potassium and molybdenum contents prepared by equal volume impregnation method and dry mixing method with space velocity was studied by using a fixed-bed integral reaction device.The variation of hydrolysis activity of different potassium and molybdenum content catalysts was investigated,and the mechanical strength of the catalysts prepared by different preparation methods was researched.Afterwards,the changing rules of deoxidation of catalysts with different compositions and reaction conditions were explored.The catalyst with the best ratio of potassium and molybdenum was selected to study the anti-oxidation ability.Its main conclusions are as follows:?1?Both the catalysts prepared by the dry-mixing method and equal volume impregnation method,their the COS hydrolysis activity increase with the increase of the potassium content and decreases with the increase of the molybdenum content.The COS hydrolysis ability of the catalyst increases with the increase of the reaction temperature,and the increasing of the COS hydrolysis activity of the catalyst with low conversion at low temperature is more obvious with the reaction temperature increasing.Pre-sulfidation,on the other hand,leads to a decrease in the COS hydrolysis activity of the catalyst.The more molybdenum content in the catalyst,the more pronounced the decrease in hydrolysis activity after presulfidation.?2?The catalysts prepared by the dry-mixing method have poor mechanical strength so they are not suitable for practical applications though they have higher COS hydrolysis activities then the catalysts prepared by the equal volume impregnation method.The catalysts prepared by the equal volume impregnation method are suitable for use in actual production because of their good mechanical strength.?3?The deoxidation ability of the catalyst showed a trend of increasing first and then decreasing with the potassium content,reaching the maximum at the molybdenum content of 5%;the deoxidizing ability increased with the increase of the potassium content,and the deoxidation activity began to decrease after the potassium content increased to 15%.The catalyst with higher deoxidation activity is sensitive to temperature and hydrogen concentration in the reaction gas.The higher the reaction temperature,the higher the hydrogen concentration,and the better the deoxygenation effect of the catalyst.The concentration of hydrogen sulfide in the reaction gas has little effect on the deoxidation of the catalyst,but the deoxidation effect of the catalyst with better activity in carbonyl sulfide is slightly better than that of deoxidation in hydrogen sulfide.The long-term storage of the catalyst after the pre-sulfidation treatment results in a decrease in the deoxidation activity of the catalyst due to the loss of sulfur-containing components,but the deoxygenation activity of the catalyst is recovered when the catalyst is put into a sulfur-containing atmosphere renewedly.?4?The best composition ratio of the catalyst is potassium content 15%,molybdenum content 5%,spherical alumina content 80%.The catalyst prepared by this ratio has the best deoxidation ratio 95.66%and better COS hydrolysis ratio 93.22%under the condition of the reaction temperature was 300°C and the space velocity was 5000h^-1 and the carbonyl sulfide content was 700mg S/m³ and the hydrogen concentration was 55%⁶0%..The COS hydrolysis activity was stable when the sulfidation reached saturated.The XRD pattern of the catalyst showed that the introduction of molybdenum in the catalyst could indeed achieve the purpose of anti-oxidation by removing the oxygen in the reaction.