The Synthesis Of Modified Molecular Sieve MCM-41 For Adsorptive Removal Of H₂S From Natural Gas

Hydrogen sulfide is a rotten and toxic gas.Hydrogen sulfide can corrode pipelines and production facilities,and cause catalysts poisoning in the middle and lower reaches of the device.Therefore,before putting the natural gas into use processing,hydrogen sulfide needs removal from natural gas.In this paper,modified MCM-41 molecular sieve adopted impregnation by amine were prepared as a adsorbent to desulphurization.The adsorbents were characterized by thermogravimetric-differential thermal analysis(TG-DTA),X-ray diffraction(XRD),fourier transform infrared(FT-IR),specific surface area(N2-BET),scanning electron microscope(SEM)and transmission electron microscope(TEM).The mixture of hydrogen sulphide,nitrogen,and oxygen and mix was used to simulate the raw gas.In a fixed-bed reactor for removal of hydrogen sulfide test,the influence of preparation condition and adsorption condition on t he performance of hydrogen sulphide removal were studied.Results of the experiment showed that(1)Polyethyleneimine modified MCM-41 molecular sieve adsorbent: the absorbent with PEI impregnation concentration of 30 %,Impregnation time 30 min,drying time of 4 h,drying temperature 100 oC were discovered to give the best preparation conditions.The rate of gas flow by 20mL/min and adsorption temperature of 25 oC were discovered to give the best process conditions.The saturated H2 S capacity and H2 S removal rate reached 40.19 mg/g and 42.15 %,respectively.On the Nitrogen condition,the regeneration temperature 250 oC,regeneration time 3 h,regeneration 3 times,the adsorbent till maintains excellent adsorption performance.And found that the adsorption kinetics of hydrogen sulfide of adsorbent followed Bangham dynamic equation,and obtained the ideal adsorption equation by fitting.(2)N-[3-(Trlmethoxyslly)propyl] ethylenedlamine modified MCM-41 molecular sieve adsorbent: the absorbent with APTMS impregnation concentration of 20%,refluxing temperature 100 oC,drying temperature of 100 oC,the drying time for 12 h w ere discovered to give the best preparation conditions.The rate of gas flow by 20 mL/min and adsorption temperature of 45 oC were discovered to give the best process conditions.The saturated H2 S capacity and H2 S removal rate reached 46.58 mg/g and 44.83%,respectively.The H2 S adsorption kinetics suits Bangham equation and after fitting we can obtain the ideal adsorption equation.Regeneration experiments show that the absorbent have excellent recycling properties.On the Nitrogen condition,the regeneration temperature 100 oC,regeneration time 3 h,r egeneration 3 t imes,the adsorbent till ma intains excellent adsorption performance.And found that the adsorption kinetics of hydrogen sulfide of adsorbent followed Bangham dynamic equation,and obtained the ideal adsorption equation by fitting.(3)3-amino-propyl trimethoxy silane modified MCM-41 molecular sieve adsorbent: the absorbent with APTMS impregnation concentration of 0.6mL,refluxing temperature 90 oC,drying temperature of 20 oC,the drying time for 12 h were discovered to give the best preparation conditions.The rate of gas flow by 20 m L/min and adsorption temperature of 45 oC were discovered to give the best process conditions.The saturated H2 S capacity and H2 S removal rate reached 138.4 mg/g and 54.2 %,respectively.On the Nitrogen condition,the regeneration temperature 150 oC,regeneration time 3 h,regeneration 3 times,the adsorbent till ma intains excellent adsorption performance.And found that the adsorption kinetics of hydrogen sulfide of adsorbent followed Bangham dynamic equation,and obtained the ideal adsorption equation by fitting.