Removal Of Trace Hydrogen Sulfide From Natural Gas By Titanosilicite Zeolite

Natural gas is an important marine resource.Natural gas often contains hydrogen sulfide,which can cause equipment corrosion and catalyst poisoning in natural gas extraction,processing,and transportation.As clean production and green petrochemical concepts have received widespread attention,the research on resource utilization,pollution-free and efficient removal of trace hydrogen sulfide from natural gas is of great significance.titanosilicite zeolite was used to catalyze the oxidation of hydrogen peroxide to remove organic sulfur from fuel.It is a structurally stable oxidation catalyst.If titanosilicite zeolite and hydrogen peroxide are used to catalyze the oxidation of hydrogen sulfide,the product will be elemental sulfur and water or dilute sulfuric acid.The process is a resource-free and pollution-free process.In this paper,a mixture of hydrogen sulfide and nitrogen is used as a simulated natural gas,and the effect of molecular sieves with different silicon-to-titanium ratios on desulfurization is investigated,the desulfurization process is optimized,and the desulfurization mechanism is preliminary analyzed.Using ethyl orthosilicate as the silicon source,tetrabutyl titanate as the titanium source,and tetrapropyl ammonium hydroxide as the template,the titanosilicite zeolite with different silicon-to-titanium ratios were successfully synthesized by the hydrothermal synthesis method,and they were loaded separately by the impregnation method.With 3%,8%,15% iron element by mass ratio.The catalyst was characterized by X-ray powder diffraction,Fourier infrared and thermogravimetry.The results show that the samples with the molar ratio of silicon to titanium of 20,50,and 100 all have TS-1 molecular sieves with MFI topology.At 20 ℃ and 0.5 g of catalyst,the removal rates of hydrogen sulfide were9.20%,0.17%,and 0.17%,respectively.When 1% hydrogen peroxide was added to the system,the removal rates of hydrogen sulfide were 74.01%,82.84%,and 67.32%,respectively,it can be seen that the titanosilicite zeolite with a silicon to titanium ratio of 50 has a better removal rate of hydrogen sulfide.The removal rates of hydrogen sulfide after loading iron are 77.77%,79.06%,and 84.22%,respectively,indicating that loading iron has no significant effect on the removal of hydrogen sulfide.The factors affecting the removal rate of hydrogen sulfide were studied,and the results showed that the removal rate of hydrogen sulfide increased with the increase of hydrogen peroxide concentration and temperature;with the decrease of p H,the removal rate of hydrogen sulfide decreased.The desulfurization process was optimized by response surface analysis,and it was concluded that the optimal reaction conditions were 78 g/L of hydrogen peroxide,temperature of 20 ℃,and p H of 4.18.Using arsenazo Ⅲ and X-ray photoelectron analysis,it is found that the desulfurization product is elemental sulfur.The molecular sieve after the desulfurization reaction is calcined at high temperature to remove the elemental sulfur,and the desulfurization reaction is repeated,and it is found that the desulfurization rate is still high.Isopropanol,p-benzoquinone,ascorbic acid,and 2,6-di-tert-butyl-4-methylphenol were added to the reaction system.As a result,it was found that no hydroxyl radicals and Superoxide anion radical were involved in the reaction.It is the free radical titanium peroxide Ti-OOH that participates in the reaction.