Molecular sieve catalysts are one of the most studied fluidized bed catalysts.Molecular sieve microsphere catalysts are typically prepared by spraydrying processes,which used double aluminum-based sol,silica-aluminum composite sol,phosphorus-aluminum sol,etc.as binders in industry.The fluidized bed catalysts required not only good catalytic performance,but also superiorattrition resistance,favourable sphericity and appropriate particle size distribution to match the actual industrial manufacturing.The attri-tion resistance,particle size distribution,sphericity and catalytic performance of molecular sieve catalysts are significantly affected by the selection of binders and supports,the slurry preparation processes,the inlet and outlet temperatures of the spraydrying processes,the atomizer speed and the post-processing of the catalysts.The current research progresseson improving the attrition resistance of fluidized bed molecular sieve catalysts(FCC catalysts and MTO catalysts are taken as examplesin this paper)are summarized from three aspects including optimization of catalyst slurry components,optimization of spraydrying proces-ses and post-processing of catalysts,and provide some references for the research & development of other attrition resistant fluidized bed catalysts.
Aldol condensation of furfural with cyclopentanone is one of the important steps in preparation of the high-quality biofuels.The synthesis of renewable biofuels from biomass furfural and cyclopentanone is sustainable and meets the requirements of green chemistry.However,the catalytic mechanism of this reaction are not very clear.Under different catalysis,two products can be obtained,2,5-bis(2-furanylmeth-ylene)cyclopentanone(F2Cp)and 2-(2-furanylmethylene)cyclopentanone(FCP).In this paper,the catalytic performances of acid catalyst,base catalyst and acid-base bifunctional catalyst used in the reac-tion for target product of F2Cp were analyzed.The analysis shows that both acidic Al2O3 catalyst and acid-base bifunctional Na-HAP catalyst have better catalytic performance.The microwave radiation method can increase the reaction rate under free solvent.On this basis,the catalytic mechanism is described and ana-lyzed.The mechanism analysis shows that the acid-base synergism is beneficial to the aldol condensation reaction.Therefore,the design and preparation of solid acid-base bifunctional catalysts with appropriate acid-base ratio is the focus of the follow-up study of this reaction,and also provide some references for the aldol condensation reaction of other aldehydes or ketones.
5％TiO2-nMoO3 catalysts with different amounts of MoO3 were prepared by molten salt roasting and impregnation.The hydrodesulfurization activity of the catalysts was evaluated by using dibenzothio-phene/cyclohexane solution as model reactant in a self-made high pressure micro reactor.XRD,BET,H2-TPR and NH3-TPD were used to characterize the phase structure,specific surface area,reduction per-formance and surface acidity of the catalysts.The results showed that when the reaction pressure was 4.0 MPa,liquid hourly space velocity was 10 h-1,and the volume ratio of hydrogen to oil was 600∶1.the hydrodesulfurization activity increased firstly and then decreased with increasing of MoO3 amount.When the amount of MoO3 was 15％,the maximum hydrodesulfurization conversion of dibenzothiophene could reach 30.08％,95.35％and 97.42％at 280 ℃,300℃and 320 ℃.The desulfurization of dibenzothio-phene over 5％TiO2-nMoO3 catalyst was mainly carried out by direct desulfurization.
The performance of ruthenium catalysts supported by different carriers based on impregnation method in liquid hydrogenation of 4,4'-diaminodicyclohexyl methane to trans-trans isomeric PACM was investigated,and the influence of the second metal additive on the performance of catalysts was studied.The results showed that the activity and selectivity of catalysts were significantly improved after the addi-tion of metal Re,and the optimal loading ratio of Ru∶Re is 5∶1.The content of PACM trans-trans isomer is less than 20％.The catalyst has good stability.
Copper metal organic framework material(Cu-MOF)was synthesized by steam induction method,and cerium was introduced into the Cu-MOF skeleton structure by impregnation method to obtain com-posite precursor.Then,a new type of Cu-based composite oxide was prepared by high-temperature heat treatment.It was found that the doping of cerium could modify the crystal structure of Cu-based composites.As well-prepared catalysts,the effect of cerium loading was investigated on the catalytic performance of Cu-Ce composite oxides,and to obtain the optimal preparation conditions of the catalyst.The optimized composite catalyst exhibited efficient catalytic oxidation activity for CO under 180 ℃ conditions,with a space velocity of 50 000 h 1 and CO removal efficiency of over 99％.In addition,the addition of TiO2 in the synthesis of Cu-MOF could modulate the formation of CuO and promote the catalytic performance of the catalyst for CO oxidation.
