Preparation Of Alumina Ceramic Substrate Molecular Sieve Membranes And Their Dehydration Performance For Natural Gas

The presence of water vapor in natural gas may cause corrosion of pipes and equipment,even form ice plugs,block pipes,and affect the normal transportation of natural gas.Therefore,dehydration is required before natural gas is delivered.Membrane separation is an effective method for dehydration from natural gas.At present,the hotspots of membrane materials research have begun to change inorganic membranes from organic membranes.The research on molecular sieve membranes has attracted people's attention in the past 10 years.The molecular sieve membrane is synthesized by molecular sieve loading onto a carrier,it has a uniform pore size,effective pores,and its corrosion resistance and high temperature resistance,and has extremely critical theoretical and application value.Global researchers have begun to research and develop to this technology.In this experiment,A-type molecular sieves and T-type molecular sieves were synthesized by hydrothermal synthesis.These two molecular sieves were used for seed crystals,with the Alumina ceramics as basement membrane,T-type and A-type zeolite membranes were synthrsized by precoating the substrate on the seeds successfully.These two membrane meterials were used for the research of natural gas dehydration performance,and the results showed that the H₂O/CH₄ selectivity of T-type molecular sieve membrane and A-type molecular sieve membrane for natural gas dehydration were 2.80 and 3.16 respectively.The effects of the thickness of the T-type zeolite membrane and the ion exchanges of the A-type zeolite membrane on the natural gas dehydration performance were investigated respectively.The results showed that the thickness of the T-type zeolite membrane has a certain influence on the permeability and H₂O/CH₄ selectivity of natural gas dehydration.For the A-type zeolite membrane,the selectivity of H₂O/CH₄ could be added from 1.19 to 3.16 through the ion exchange number.The surface coating and soaking methods were used to repair the defects of the two molecular sieve membrane,and the result showed that the surface coating repairing method could effectively improve the natural gas dehydration performance of the membrane material,the H₂O/CH₄ selectivity of the repaired T-type molecular sieve membrane increased from 2.80 to 10.52,the H₂O/CH₄ selectivity of the type A zeolite membrane increased from 3.16 to 17.71.Two molecular sieve membranes had good recycling performance,they could be recycled at least three times,and the natural gas dehydration performance almost have no changes.