Modification Of Na Y And MCM-41 Zeolites And Their Adsorption Capacity In The Adsorption Desulfurization From Diesel

Recent years,fuel desulfurization methods are mainly hydrodesulfurization,adsorption desulfurization,extraction desulfurization,oxidation desulfurization,biologicaldesulfurization,alkylationdesulfurization.Theconventional hydrodesulfurization requires high temperature and high pressure conditions,consuming large amounts of hydrogen,reducing the octane number of the fuel,and making it difficult to remove cyclic sulfides.The adsorption desulfurization has the characteristics of low operating temperature,no consumption of hydrogen and little octane loss,and hence the research on adsorption desulfurization is deepening.The widely used adsorbents are mainly metal oxides,activated carbon,molecular sieve and so on.Among them,Y molecular sieve possess unique pore structure,hydrothermal stability and surface acidity and other characteristics,can be applied in a large number of production applications.However,the current research on microporous zeolite Y as adsorbent is not perfect,and its adsorption capacity of sulfur compounds in fuel is not high.Therefore,the experiment needs to microporous molecular sieve Y modification method for more in-depth study.The desulfurization performance of the adsorbent was investigated in a laboratory static reactor.The physical and chemical properties of the adsorbent were characterized by XRD,BET,XRF,NH₃-TPD and TEM.And the desulfurization performance of the adsorbent was discussed.The adsorption of sulfur compounds on the adsorbent was also discussed.Alkali treatment?0.10mol/L NaOH?introduces some mesoporous channels inside the NaY molecular sieve,which not only makes the thiophene and benzothiophene molecules more easily diffused through the channels of the molecular sieve,so that the sulfur-containing compounds are rapidly contacted with the molecular sieve,increasing the adsorption rate and the adsorption capacity of the sulfur-containing compound.In addition,Ni²⁺and Ce⁴⁺were introduced into NaY and Alkali treated NaY by ion exchanging.The results of static adsorption showed that Ni²⁺and Ce⁴⁺could increase the adsorption capacity of molecular sieve after introduction of mesopores.In this paper,the adsorption isotherms and adsorption kinetics of thiophene and benzothiophene were also studied.The different model equations Langmuir and Freundlich were used to calculate the adsorption isotherms.The psedo-first and second model equations were used to calculate??G,?H,?S?of the molecular sieve adsorption of thiophene and benzothiophene by molecular sieve adsorption activation energy.The mesoporous molecular sieve was used to adsorb desulfurization directly after the introduction of mesoporous molecular sieves and mesoporous molecular sieves.The adsorption of sulfur compounds in fuel was investigated by MCM-41molecular sieves after introducing K⁺ions and Ce⁴⁺.The results show that the introduction of K⁺ions can make the distribution of metal ions in the molecular sieve more uniform.