Study On The Performance Of Hierarchical ZSM-35 Zeolite In Dimethyl Ether Carbonylation

China will fully promote the use of E10 ethanol gasoline（90wt%gasoline+10wt%ethanol）in 2020,while the ethanol market gap is huge.Coal-to-ethanol technology meets our country’s energy structure characteristics"more coal,less gas,and lean oil",and can solve the problem of"competing with people for food and competing with food for land"with the fermentation method effectively.The dimethyl ether（DME）carbonylation route method is an emerging coal-to-ethanol technology,which has attracted much attention due to its mild reaction conditions,high atomic economy,good selectivity and cheap needed catalyst,whose key step is to get DME carbonylation prepare methyl acetate（MA）.Due to the regular pore structure and uniform acid distribution of Ferrierite（ZSM-35 molecular sieve,FER molecular sieve）,it performs well in the DME carbonylation reaction.Its reaction characteristics are high selectivity,good stability and low activity.It has good stability because the smaller ten-membered ring channel does not allow macromolecular hydrocarbons to enter,reducing the rate of carbon formation.Its low activity limits its industrial application,probably owing to the presence of a smaller FER cage,preventing most molecules from entering the cage.In this thesis,the modification of Ferrierite is to improve its reactivity under the premise of ensuring its reaction stability as much as possible.In this paper,the commercial ferrierite was treated with HNO₃ solution,Na OH solution,sequential Na OH solution-HNO₃ solution and NH₄F solution,then it was exchanged to H-ZSM-35 molecular sieve with NH₄NO₃ solution,which utimately is used in the DME carbonylation reaction to examine its reaction performance after undergoing Extrusion molding and milling.The structure and acid characterization of H-ZSM-35molecular sieve include XRD,XRF,SEM,TEM,N₂ adsorption desorption,NH₃-TPD and FE-IR.The DME carbonylation reaction is carried out on a high-pressure fixed-bed reactor,whose reaction conditions are as follows:pressure is 4.5 MPa,temperature is190℃,the molar ratio of mixed raw materials is DME:CO=2:5,and the space velocity of the mixed raw materials is 3000ml/（g·h）.The DME conversion rate of commercial ferrierite during the stationary phase of the reaction was 31.7%,and the stationary phase lasted to 22h.After treated with 2mol/L HNO₃ solution,the DME conversion rate of ferrierite during the stationary phase of the reaction dropped to 25.6%,but the stationary phase was extended to 68h.After treated with 0.4mol/L Na OH solution,the DME conversion rate of ferrierite in the stationary phase of the reaction rose to 35.4%,and the stationary phase was prolonged to 48h.After sequential treated with 0.4mol/L Na OH solution-2mol/L HNO₃ solution,the DME conversion rate of ferrierite during the plateau of the reaction decreased to 30.3%,but the stationary phase extended to 62h.The treatment with NH₄F solution can nearly desiliconize and dealuminate at the same time,and might open the FER cage while forming a small amount of mesopores.