The Preparation Of Supported Catalyst With Re And Its Application In Gasoline And Diesel Hydrofining

Recent years,our country is widespread by the haze especially in Beijing,Tianjin and Hebei region.It has been unbearable of the air pollution for the people.The research shows that most of the pollution comes from the vehicle exhaust.In May 20 1 2,a new automobile fuels emission standard was issued by the govemment.It provides that the sulfur content of gasoline need to be decreased from 50ppm to lOppm or less.Now,we designed a new efficient kind of catalysts to test the reactions of hydrodesulfurization(HDS)and hydrodenitrogenation(HDN)of gasoline and diesel.The sulfur content of gasoline is about of 50ppm,and the diesel is 900pprm.The catalytic results show that the gasoline can completely meet the demands of the new automobile fuels emission standard.The diesel also has generate significantly lower.First,the ternary composite oxide of SiO2-TiO2-ZrO2 which was our support was prepared following the "co-precipitation"method.Then,many series of supported Re-Mo-Ni,W-Re-Co,W-Re and Ni-Mo oxide catalysts were prepared in a aqueous solution called "co-maceration" method.The supports and the catalysts were characterized by X-ray diffraction(XRD)and N2 adsorption-desorption.By XRD,the identification of the crystalline was carried out.The XRD patterns of support show well diffraction peaks of silica and titanium dioxide.The diffraction profiles of catalysts,for the calcined materials,show peaks in the form of composite oxides.After characterizing of the support and catalysts with the N2 adsorption-desorption,it shows that they both have sizeable specific surface and small pore diameter.The average specific surface of support is 265.80m2.g-1 and the pore diameter is 6.86nm.The average specific surface and pore diameter of catalysts are smaller than the support,they are 126.15m.g-1 and 6.43nm.The results show that the active ingredient may be into the pore structure of the support which well obtain the active ingredient.We should make the powder catalyst into 20-40 mesh graininess.The HDS and HDN of the gasoline and diesel were performed in a high-pressure fixed-bed continuous-flow stainless steel catalytic reactor,operated in the down-flow mode.Prior to the activity test,the catalyst was reduced at a high temperature for hours under a hydrogen flow of 50-60mL.min-1.After that,the H2 gas was mixed with a solution of gasoline or diesel,which was supplied by means of a piston pump with liquid hourly space velocities(LHSV)ranging between 2 to 8 h-1,and then introduced to the reactor.For the activity tests,0.3mL of catalyst were used,and they were measure at different temperature(200-500?),under 2-5Mpa of H2,and with the hydrogen to oil volume ratio of 300-600.We collected the liquid samples after 60min at the wanted operating conditions to monitoring the reaction.The samples were kept in sealed vials and subsequently analyzed by TS-2000 UV&fluorescence sulfur analyzer and gas chromatography(Shimadzu SP-2100).Then we selected the catalyst with higher yields to probe the most suitable operating condition include the pressure,space velocity,hydrogen oil ratio,temperature and how long it can be used.At last,we test the gasoline and diesel which were hydrotreated to make sure they were with the nature of the former.