正庚烷催化裂解生产低碳烯烃的影响因素探索

The influence of zeolite structure and process parameters (including reaction temperature and catalyst/oil ratio) on rules for formation of ethylene and propylene in the course of catalytic pyrolysis of n-heptane was studied in a small- scale fixed fluid catalytic cracking unit. Test results have revealed that compared to the USY zeolite and Beta zeolite, the catalytic pyrolysis of n-heptane in the presence of the ZRP zeolite catalyst can result in higher yield and selectivity of ethyl- ene and propylene, while a higher reaction temperature and a higher catalyst/oil ratio can promote the formation of ethylene and propylene during catalytic pyrolysis of n-heptane. The ethylene formation reaction is more sensitive to the changes in reaction temperature, whereas the changes in catalyst/oil ratio are more influential to the propylene formation reaction. This paper has made a preliminary exploration into the different reaction pathways for formation of ethylene and propylene on zeolites with different structures.     

Synthesis of Modified β-Zeolite Under Microwave Irradiation and Its Use on Etherification

β -zeolite was synthesized by using tetraethyl ammonium hydroxide as the template reagent and microwave radiation as the heat source. The effect of the sol composition and the radiation temperature on zeolite crystallinity was investigated. The zeolite was tested and compared with the commercial product, which was produced by conventional hydrothermal synthesis method. ,The physico-chemical properties of the synthesized samples, the specific surface area of the samples synthesized under microwave irradiation and pore volume measured by X-ray diffraction apparatus, were better than the conventional samples. The etherification experiment on FCC light naphtha in the presence of transition metals modified H β -zeolite, which was synthesized firstly under microwave irradiation, was studied in a fixed-bed reactor. The effect of catalyst preparation conditions on its activity, stability and the effect of reaction temperature, methanol/tertiary-carbon olefin molar ratio and liquid hourly space velocity on the etherification reaction were discussed. The experimental results showed that the different metals modified H β -zeolite had different etherification performances. And the conversion of tertiary carbon-olefins of the molybdenum modified H β zeolite, which was loaded at a concentration of 3 percents, was higher than that on 6.0 percent of H β zeolite. The modified H β zeolite catalysts possessed favorable prospects for its higher stability.     

Propane Dehydrogenation on PtSnNa/AlSBA-15 Catalyst:Influence of Tin as a Promoter

PtSnNa/AlSBA-15 catalysts with different amounts of Sn were prepared for propane dehydrogenation.The catalysts were characterized by XRF,BET,H2 chemisorption,NH3-TPD,H2-TPR,and TPO techniques.Test results indicated that the presence of tin not only modified the acid function and the interfacial character between metal and support,but also reduced the coke deposition effectively.Among these catalysts investigated thereby,the PtSn(0.7%)Na/AlSBA-15 catalyst had the best catalytic performance in terms of propane conversion and stability.With the continuous addition of Sn,more amounts of Sn0 species appeared,which was unfavorable to the reaction.The PtSn(0.7%)Na/AlSBA-15 catalyst was parametrically characterized in order to obtain necessary information to integrate the process operating conditions.A weight hourly space velocity of 3 h-1,a reaction temperature of 610 ℃ and a H2/C3H8 molar ratio of 0.25 were found to be optimum conditions for achieving a higher dehydrogenation activity of the catalyst.     

Synthesis,characterization and catalytic application of H4SiW12O40/MCM-48 in the esterification of methacrylic acid with n-butyl alcohol

A novel environmental friendly catalyst, H4SiW12O40/MCM-48, was prepared by impregnation method. The catalysts were characterized by means of XRD and FT-IR. The synthesis of n-butyl methacrylate catalyzed by H4SiW12O40/MCM-48 was studied with methacrylic acid and n-butyl alcohol as reactants. H4SiW12O40/MCM-48 was an excellent catalyst for the synthesis of n-butyl methacrylate and Keggin structure ofH4SiW12O40 kept unchanged after impregnated on surface of the molecular sieve support. Effects of n（methacrylic acid）： n（n-butyl alcohol）, catalyst dosage, cyclohexane （water-stripped reagent） and reaction time on the yields of the product were investigated. The optimum conditions have been found, that is, molar ratio of acid to alcohol is 1：1.5, mass ratio of catalyst used to the reactant is 1.5%, cyclohexane is 10 mL and reaction time is 1.5h. Under these conditions, the yield of n-butyl methacrylate can reach 73.2%.     

Synthesis, characterization and catalytic properties of Y-β zeolite composites

Y-β zeolite composites were hydrothermally synthesized by using high silica Y zeolite as the precursor and characterized by XRD,N2 adsorption,SEM and IR spectra of pyridine.The result showed that the N2 adsorption-desorption isotherm of the zeolite composites had a distinct hysteresis loop,and the SEM result showed that the zeolite composites had a different morphology from Y,β and the corresponding physical zeolite mixture.The acid catalytic performance of the zeolite composite catalysts was investigated in the hydrocracking and hydroisomerization of n-octane,and the results showed that the composite materials exhibited an excellent hydrocracking activity and good hydroisomerization performance.The yield of i-C4 over the zeolite composite catalyst was 4.45% higher than that on the corresponding zeolite mixture in the n-octane hydrocracking process at 553 K.The isomerization ability of n-octane over the composite catalyst was 3.6 fold that of the corresponding mixture at 503 K.     

活性膨润土在甲苯叔丁基化中的应用

tert-Butylation of toluene with tert-butanol used as the alkylating agent was investigated over the activated bentonite and HY zeolite used as the catalyst.The influences of various butylation reaction parameters,including the toluene/tert-butanol ratio,the reaction temperature,and the space velocity were discussed.The optimal results were obtained at a reaction temperature of 180 ℃,a space velocity of 4 h-1,and a mole ratio of toluene to tert-butanol equating to 2.The structure and acidic properties of catalyst were characterized by the BET method and the Fourier transform infrared (FTIR) spectroscopy.Compared with the HY zeolite,the activated bentonite possessed high activity for toluene conversion and high para-selectivity because it had larger pore diameter,smaller micropore surface area and higher ratio of total Lewis acids to total Br nsted acids.     

Research on Ethylene and Propylene Formation during Catalytic Pyrolysis of Methylcyclohexane

The influence of operating parameters and type of zeolite catalysts on formation of ethylene and propylene during catalytic pyrolysis of methylcyclohexane (MCH) was studied in a laboratory fixed fluidized bed reactor. The results indicated that higher reaction temperature and lower WHSV tended to produce more ethylene and propylene, among which the reaction temperature was an important factor influencing the ethylene formation. Compared with the FAU and BEA type zeolites, the MFI structured zeolite catalyst, thanks to more acid sites and smaller pore diameter of the catalyst, was conducive to the formation of ethylene and propylene. The protonation occurred on different C—C bonds and C—H bonds in the carbon chain of MCH led to different product slates, and the protonation on C—C bonds located at naphthenic ring was favorable to the formation of ethylene and propylene.     

Preparation of a highly efficient Pt/USY catalyst for hydrogenation and selective ring-opening reaction of tetralin

Ultrastable Y zeolite(USY)-supported Pt catalyst was prepared by gas-bubbling-assisted membrane reduction. The influence of reaction conditions and the metal and acid sites of catalysts on the catalytic performance of catalyst in hydrogenation and selective ring opening of tetralin, 1,2,3,4-tetrahydronaphthalene(THN), was studied. It was found that the optimal reaction conditions were at a temperature of 280 °C, hydrogen pressure of 4 MPa, liquid hourly space velocity of 2 h~(-1) and H_2/THN ratio of 750. Under these optimal conditions, a high conversion of almost 100% was achieved on the 0.3 Pt/USY catalyst. XRD patterns and TEM images revealed that Pt particles were highly dispersed on the USY, favorable to the hydrogenation reaction of tetralin. Ammonia temperature-programmed desorption and Py-IR results indicated that the introduction of Pt can reduce the acid sites of USY, particularly the strong acid sites of USY. Thus, the hydrocracking reaction can be suppressed.     

二氧化硅负载Cr(acac)3/PNP催化剂的制备及其催化乙烯四聚反应性能研究

Chromium acetylacetonate and bis(diphenylphosphino)isopropylamine were coordinated in situ and supported on methylaluminoxane-modified silica. The catalyst structure and effects of reaction temperature, reaction pressure and Al/Cr molar ratio on ethylene tetramerization were investigated in detail. Chromium was uniformly and firmly immobilized on the support and could not be leached off by methylaluminoxane. The supported catalyst, upon being activated with methylaluminoxane, exhibited catalytic activity of 1.70×107 g/(mol Cr·h) for ethylene tetramerization to form 1-octene at a reaction temperatures of 80 ℃, a pressure of 2.0 MPa and an Al/Cr molar ratio of 300. The supported catalyst presented a good tolerance to high temperature.     

Effect of Olefins on Formation of Sulfur Compounds in FCC Gasoline

The effect of olefins on formation of sulfur compounds in FCC gasoline was studied in a small-scale fixed fluidized bed （FFB） unit at temperatures ranging from 400℃ to 500℃, a weight hourly space velocity （WHSV） of 10 h-1, and a catalyst/oil ratio of 6. The results showed that C4--C6 olefins contained in the FCC gasoline could react with HzS to form predominantly thiophenes, alkyl-thiophenes as well as a fractional amount of thiols, while large molecular olefins such as heptene could react with hydrogen sulfide to form benzothiophenes. The amount of sulfur compounds formed at different tem- peratures over different catalysts were in proportion to the mass fractions of olefins in the feedstock, with the amount of sulfur compounds formed over REUSY catalyst exceeding those formed over the shape selective zeolite catalyst owing to the effect of catalyst performance and the impact of catalyst on the degree of olefin conversion. The amount of sulfur compounds generated and their increase reached a maximum at 450℃ and a minimum at 400℃ because of the influence of temperature on the thermodynamic and kinetic constants for formation of sulfur compound as well as on the olefin conversion degree. Based on the above-mentioned study, a reaction network and a model for prediction of sulfur compounds generated upon reaction of olefins in FCC gasoline with HES were established.     

Catalytic performance of Pt/HY-β in n-octane hydroisomerization

A bifunctional catalyst Pt/HY-β was prepared from a bimicroporous composite zeolite Y-β. Characterization results showed that the specific surface area, pore volume, and acid amount of the catalyst Pt/HY-β all decreased compared to the original zeolite. The catalytic performance of this catalyst in n-octane hydroisomerization was investigated in a fixed bed stainless steel tubular reactor. The results showed that at a hydrogen/n-octane volume ratio of 1000, pressure of 0.6 MPa, temperature of 230 ℃ and LHSV of 3 h^-1, the conversion of n-octane, yield of liquid, hydrocracking rate and yield of iso-octane were 52.32%, 88.66%, 12.60%, 39.51%, respectively.     

Effect of Addition Sequence during Neutralization and Precipitation on Iron-based Catalysts for High Temperature Shift Reaction

The preparation of the iron-based catalysts promoted by cobalt with a small amount of copper and aluminum for the high temperature shift reaction(HTS)with different sequences of adding catalyst raw materials during neutralization and precipitation was investigated.XRD,BET and particle size distribution(PSD)were used to characterize the prepared catalysts.It was found that the catalyst crystals were allγ-Fe 2 O3,and the intermediate of the catalyst after aging was Fe3O4.The crystallographic form of the catalyst and its intermediate was not affected by the addition sequence in the neutralization and precipitation process.The results showed that the specific surface area and the particle size of the catalysts depended on the addition sequence to the mother liquor. Cobalt with a small amount of copper and aluminum could increase the specific surface area and decrease the particle size of catalysts.     

硅钨酸酸化的新型MIL-101（Cr）催化剂及其对正庚烷异构化反应的催化性能

0.4%Pt/xSTA-MIL-101(Cr) metal-acid bifunctional catalysts were prepared by impregnation using STA-MIL-101(Cr) as the support. The synthesized samples were verified to exhibit a typical octahedral structure of MIL-101(Cr) and the pore structure were arranged orderly. The specific surface area of the samples was extremely high and the samples were micro-mesoporous composite materials. Silicotungstic acid could retain its Keggin structure in the 0.4%Pt/xSTA-MIL-101(Cr) samples and the catalyst possessed moderately strong Br?nsted acid sites. Besides, the dispersion of Pt particles in MIL-101(Cr) was relatively high. n-Heptane isomerization was first used as a probe to test the novel 0.4%Pt/xSTA-MIL-10(Cr) catalyst. Compared with the conventional silicate catalysts, the catalytic performance of 0.4%Pt/30wt%STA-MIL-101(Cr) was significantly improved with n-heptane conversion of 58.93% and iso-heptane selectivity of 95.68%, respectively, when the reaction time was 2 h at the reaction temperature of 260 oC. The catalyst could still maintain a relatively high catalytic performance during the reaction time of 5 h. Compared with the non-noble metal catalysts, the catalytic efficiency is relatively high. The mechanism model of n-heptane isomerization over 0.4%Pt/xSTA-MIL-101(Cr) catalyst was established.     

Study on Olefins Yield from Methanol Conversion over Different Catalysts

Conversion of Methanol to Olefins （MTO） under different reaction conditions was experimentally investigated over different catalysts, and comparison was made between the SAPO-34 and GOR-MLC catalysts. Optimization of reaction conditions has been explored. Conversion of methanol to olefins over these catalysts under different reaction temperatures was experimentally studied. In a fixed bed micro-reactor, the influence of temperature was found to be one of the major factors. For both catalysts the olefins yield was increased significantly when water was added to the methanol feed. A temperature range of 460 480℃ appeared to be the optimum range suitable for methanol conversion with appropriate catalyst activity and C2-C3 olefins yield. Some other hydrocarbons appeared during the MTO reaction in the presence of the SAPO-34 catalyst, while a lot of dimethylether was formed when the GOR-MLC catalyst was used. In the course of the MTO reaction, the GOR-MLC catalyst was found to have a faster catalyst deactivation rate compared to the SAPO-34 catalyst.     

Catalytic performance of Cu- and Zr-modified beta zeolite catalysts in the methylation of 2-methylnaphthalene

2,6-Dimethylnaphthalene(2,6-DMN) is a commercially important chemical for the production of polyethylenenaphthalate and polybutylene naphthalate. However, its complex synthesis procedure and high production cost significantly reduce the use of 2,6-DMN. In this study, the synthesis of 2,6-DMN was investigated with methylation of 2-methylnaphthalene(2-MN) over metal-loaded beta zeolite catalysts including beta zeolite, Cu-impregnated beta zeolite and Zr-impregnated beta zeolite. The experiments were performed in a fixed-bed reactor at atmospheric pressure under a nitrogen atmosphere. The reactor was operated at a temperature range of 400–500 °C and varying weight hourly space velocity between 1 and 3 h~(-1).The results demonstrated that 2,6-DMN can be synthesized by methylation of 2-MN over beta type zeolite catalysts.Besides 2,6-DMN, the product stream also contained other DMN isomers such as 2,7-DMN, 1,3-DMN, 1,2-DMN and 2,3-DMN. The activity and selectivity of beta zeolite catalyst were remarkably enhanced by Zr impregnation, whereas Cu modification of beta zeolite catalyst had an insignificant effect on its selectivity. The highest conversion of 2-MN reached81%, the highest ratio of 2,6-DMN/2,7-DMN reached 2.6 and the highest selectivity of 2,6-DMN was found to be 20% by using Zr-modified beta zeolite catalyst.     

盐酸三乙胺-三氯化铝离子液体催化甲苯与氯代叔丁烷烷基化反应

Alkylation of toluene with 2-chloro-2-methylpropane (t-Bu-Cl) to synthesize para-tert-butyltoluene (PTBT) was carried out in the presence of triethylamine hydrochloride-aluminum chloride ionic liquids used as the catalyst. The ionic liquids were prepared with different molar ratios of Et3NHCl to AlCl3 , and the effect of the molar ratio between AlCl 3 and Et3NHCl, the reaction time, the reaction temperature, the ionic liquid dosage, as well as the molar ratio of toluene to chloro-2-methylpropane on the alkylation reaction of toluene with chloro-2-methyl-propane was investigated. The test results showed that the acidic ionic liquids prepared with Et3NHCl and AlCl3 had good activity and selectivity for the alkylation reaction of toluene with alkyl chloride to produce PTBT. The optimal reaction conditions were specified at anAlCl3 to Et3NHCl ratio of 1.6, a reaction temperature of 20℃, a mass fraction of toluene to ionic liquid of 10%, and a chloro-2-methylpropane to toluene molar ratio of 0.5. Under the suitable reaction conditions, a 98% conversion of chloro-2-methylpropane and an 82.5% selectivity of PTBT were obtained. Ionic liquids could be reused 5 times with its catalytic activity unchanged, and the regenerated ionic liquids can be recycled.     

助剂对甲烷自热重整制氢反应NiO/Al2O3催化剂引发过程的影响

The catalysts Ni/Al2O3, Ni/ZrO2-CeO2-Al2O3 and Ni/CuO-ZrO2-CeO2-Al2O3 were prepared by the co-precipitation method at a pH of 9 using Na2CO3 as the precipitant. The Ni loading(mass fraction) of the catalysts was 10%. The ignition process on the catalysts for the autothermal reforming of methane to hydrogen was investigated and the surface properties of the catalysts were characterized by XPS. The results showed that the Ni/Al2O3 catalyst could not ignite the process of autothermal reforming of methane to hydrogen. However, the Ni/CuO-ZrO2-CeO2-Al2O3 catalyst could ignite the process of autothermal reforming of methane to hydrogen at lower reaction temperature(650 ℃) with the conversion of methane reaching 76%. The result of XPS analysis indicated that the promoters could change the binding energy(BE) of Ni2p3/2 obviously. The species of Cu in the Ni/CuO-ZrO2-CeO2-Al2O3 catalyst comprised Cu2 O and Cu2+. The formation of ZrO2-CeO2 solid solution and a large amount of Cu2 O might be the reason leading to good oxygen storage capacity and mobility of lattice oxygen of the Ni/CuO-ZrO2-CeO2-Al2O3 catalyst, which could ignite the process of autothermal reforming of methane to hydrogen at lower reaction temperature.     

ZrOCl2?8H2O: 一种低廉高效的催化剂在酯化反应中的应用

The esterification of lauric acid with methanol could be efficiently catalyzed by ZrOCl2·8H2O, and this reaction was studied to develop a green method for biodiesel production. The influencing factors, such as amount of catalyst, reaction time and molar ratio of acid to methanol, were investigated. The results indicated that the ZrOCl2·8H2O catalyst showed high catalytic activity, and gave a 97.0% methyl laurate conversion rate under the following optimized conditions, viz.: a lauric acid/methanol molar ratio of 1:10, a catalyst dosage of 4%, and a reaction duration of 2 h at methanol refluxing temperature. The catalyst could be easily recovered while its activity could be well retained after three cycles. The ZrOCl2·8H2O catalyst also exhibited excellent catalytic activity for the esterification of different free long-chain fatty acids(including nonedible oils with high acid value) with different short carbon chain alcohols. Therefore, the ZrOCl2·8H2O catalyst has good potential for the synthesis of biodiesel from low-cost feedstocks such as waste vegetable oils and non-edible oils.     

Synthesis of Polyalphaolefins on AlCl3/TiCl4 Catalyst

The oligomerzation reactions on different catalysts were investigated and discussed. 1-Octene, 1-decene, 1-dodecene, a mixture of olefins (with a mass ratio of w(1-octene): w(1-decene):w(1-dodecene) equating to 30:40:30), and the products from paraffin cracking were oligomerized on the AlCl3/TiCl4 catalyst. The results indicated that the AlCl3 catalyst led to severe coking reaction. With an increase in carbon number of alpha-olefins, the freezing point of oligomers increased and the kinematic viscosity decreased. The oligomers formed from the mixed olefins and the paraffin cracking products showed higher kinematic viscosity. Normal paraffins contained in the cracked products could increase the freezing point of oligomers. Furthermore, the distillation range of oligomers obtained from the cracked products was close to those of oligomers originated from 1-octene and 1-decene, while the oligomers obtained from the mixed olefins and 1-dodecene had similar distillation ranges.     

回炼油催化裂化及PSO-RBF神经网络模型

Catalytic cracking experiments of FCC cycle oil were carried out in a fixed fluidized bed reactor. Effects of reac- tion conditions, such as temperature, catalyst to oil ratio and weight hourly space velocity, were investigated. Hydrocarbon composition of gasoline was analyzed by gas chromatograph. Experimental results showed that conversion of cycle oil was low on account of its poor crackability performance, and the effect of reaction conditions on gasoline yield was obvi- ous. The paraffin content was very high in gasoline. Based on the experimental yields under different reaction conditions, a model for prediction of gasoline and diesel yields was established by radial basis function neural network （RBFNN）. In the model, the product yield was viewed as function of reaction conditions. Particle swarm optimization （PSO） algorithm with global search capability was used to obtain optimal conditions for a highest yield of light oil. The results showed that the yield of gasoline and diesel predicted by RBF neural network agreed well with the experimental values. The optimized reac- tion conditions were obtained at a reaction temperature of around 520 ~C, a catalyst to oil ratio of 7.4 and a space velocity of 8 h~. The predicted total yield of gasoline and diesel reached 42.2% under optimized conditions.