| Natural gas,as a kind of high-quality clean fossil energy,has been widely used in many fields such as chemical industry,power generation,transportation and fuel cells.However,how to achieve deep desulfurization of natural gas,especially organic sulfur which is difficult to remove,has become a research hotspot in order to meet environmental protection and industrial requirements.The hierarchical zeolites material has broad application prospects in the field of adsorption desulfurization,because of the characteristics of multiple regular and orderly pore structure,high specific surface area,large pore volume,flexible skeleton composition and easy functional modification.In this paper,microporous ZSM-5 and ZSM-11 zeolites were prepared by hydrothermal crystallization method,and adsorbed dimethyl sulfide by dynamic fixed bed test compared with commercial HZSM-5(Si/Al=50),H?,13X and other zeolites.The experimental results showed that the order of adsorption of dimethyl sulfide is:Na ZSM-5?HZSM-5>13X>H?>>ZSM-11>USY>SAPO-34.The ZSM-5 zeolite with excellent adsorption effect was selected as the research object.A and P for soft templating agents were used to further one-step hydrothermal crystallization.A-ZS and P-ZS zeolites with micro-mesoporous structure were successfully prepared.It was found that hierarchical P-ZS zeolite presented better effect on adsorption of methyl sulfide.To use hierarchical P-ZS as the carrier,through the loading method(including solid phase grinding,equal volume ultrasonic impregnation,complex-assisted impregnation),metal salt or metal ammonia complex in-situ synthesis modification method,etc.P-ZS was functionally modified to prepare a series of copper-based modified hierarchical P-ZS adsorbents.The structure was characterized by Fourier transform infrared spectroscopy(FT-IR),X-ray powder diffractometry(XRD)and nano-particle size analyzer(DLS),and the adsorption performance of dimethyl sulfide was further investigated.The experimental results showed that the adsorption performance of[Cu,Al]P-ZS modified by metal ammonia complexes on dimethyl sulfide is better than other modification methods;the structural characterization showed that the hierarchical P-ZS has not changed through the introduction of metals.In order to further improve the deep desulfurization effect of adsorbent on dimethyl sulfide,the in-situ synthetic modified P-ZS under metals Ag(I),Cu(II),Ni(II),Ce(III)and their different concentrations were investigated.The desulfurization effect,in which[Ag,Al]P-ZS zeolite exhibited excellent adsorption performance for dimethyl sulfide,the saturated adsorption sulfur capacity can reach 24.93 mg S·g-1adsorbent,and the breakthrough sulfur capacity is also as high as 14.84 mg S·g-1adsorbent when the export sulfur content is controlled below 2?g·g-1.achieving the goal of deep desulfurization.The effects of adsorption temperature,initial sulfur concentration,water content and different sulfides on the desulfurization performance of hierarchical[Ag,Al]P-ZS were investigated by liquid-phase batch adsorption experiments.The results showed that the adsorption of dimethyl sulfide,ethyl sulfide,methyl mercaptan and ethanethiol is better at normal temperature,and the adsorption effect of dimethyl disulfide is general;in addition,the adsorbent took on a certain degree of water repellency.The water content has little effect on the desulfurization of the adsorbent.The thermal regeneration effect of the adsorbent at350°C under flowing nitrogen atmosphere is good.After the 8th regeneration,the saturated sulfur capacity of the adsorbent can still reach 93.93%compared with the fresh sample.At the same time,based on the experimental results and characterization analysis,the mechanism of[Ag,Al]P-ZS removal of methyl sulfide was presumed. |
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