天津大学等单位合作在独山子进行新型镍基裂解汽油一段加氢催化剂性能评价

裂解汽油是热裂解制乙烯时的副产物，其主要组成为C5～C9烃类，包括烷烃、烯烃、二烯烃和芳烃。裂解汽油的产量可达乙烯装置生产能力的60％～80％，是抽提芳烃的重要来源。裂解汽油稳定性差，通常必须经过两段催化加氢处理后才能进行进一步加工。裂解汽油一段加氢的主要目的是将原料中的双烯烃与链烯基芳烃进行选择性加氢而转化为单烯烃和烷基芳烃，目前工业上一般采用负载型Pd基贵金属催化剂或Ni基非贵金属催化剂。     

C_5抽余油与非芳烃汽油混合加氢工艺技术研究与工业应用

对C_5抽余油与非芳烃汽油混合加氢制备蒸汽裂解料技术的工艺条件进行了研究,考察工艺条件对转化率的影响。得出适宜的工艺条件为:稀释进料,C_5抽余油/非芳烃汽油体积比(1∶5)~(1∶7)、平均反应温度120~140℃、压力4.0~5.0 MPa、体积空速1.0~4.0h~(-1)、氢油体积比200~400。在此条件下加氢后反应产物中二烯烃质量分数不大于0.1%。1 500h的稳定性试验结果表明,该催化剂具有良好的活性和稳定性。     

FCC轻汽油非贵金属二烯烃选择加氢催化剂

采用非贵金属镍基二烯烃选择加氢催化剂,以催化裂化汽油不大于C6馏分(干点不大于75℃)为原料,在50~60℃,1.5 MPa,液体空速为2.0~4.0 h-1,氢气/原料体积比为12~24的条件下,进行选择性加氢反应。结果表明,反应中二烯烃转化率为100%;叔戊烯质量分数增加率始终大于2%;反应至800 h后,C5单烯质量分数减少量小于1%。     

在HZSM—5催化剂上重质原油的催化裂解／重整试验

本文考察了重质原油在HZSM-5分子筛催化剂上直接催化裂解/重整反应的试验情况.在反应温度为400℃～600℃,重量空速为1.0～5.0h~(-1),常压下原油的转化率可达60～80%,汽油产品的收率可达40～55%,它的芳烃含量高达70～85%,焦炭产率在5%以下.同时也探讨了重质油品在HZSM-5分子筛催化剂上的两步式裂解/重整反应机理.     

FCC操作条件对汽油族组成及辛烷值的影响

通过对一种工业FCC催化剂在固定流化床上的评价 ,揭示了反应温度、剂油比和空速对汽油族组成及辛烷值影响的一些规律。研究发现 :随着反应温度的上升汽油中的总烷烃和异构烷烃含量下降 ,烯烃和芳烃含量上升 ;随着剂油比的增加 ,汽油中的总烷烃、异构烷烃和芳烃含量上升 ,烯烃含量下降 ;环烷烃、总烷烃、烯烃和芳烃的含量随着空速的变化出现相互交叉的现象 ;而汽油的辛烷值 (RON和MON)仅是转化率的函数 ,与达到同一转化率的操作条件无关     

分子筛改性Co/SiO_2催化剂对Fischer-Tropsch合成汽油类烃的影响

在中孔SiO2中添加USY,HZSM-5,β分子筛组成双功能载体,并采用初湿浸渍法在载体上浸渍钴盐,制备了一系列分子筛改性的Co/SiO2催化剂,考察了分子筛的类型、HZSM-5分子筛的骨架硅铝比、HZSM-5分子筛在载体中的含量对Fischer-Tropsch合成汽油类烃(C5~12)的影响。实验结果表明,载体中SiO2和分子筛共同作用,提高了催化剂的活性,并使产物分布向汽油类烃偏移,其中,以HZSM-5分子筛改性的Co/SiO2催化剂的催化性能最好。HZSM-5分子筛改性催化剂对催化性能的影响受其骨架硅铝比的影响。当骨架硅铝比n(SiO2)∶n(Al2O3)=38、HZSM-5分子筛在载体中的质量分数为20%时,CO转化率达到80%以上,汽油类烃的选择性高达55%,其中异构烷烃的选择性在10%以上。     

ZnNi/HZSM-5催化剂上混合C4烃的芳构化反应

考察了ZnNi/HZSM-5催化剂制备方法和反应条件对混合C4烃芳构化反应的影响，并探讨了反应机理，结果表明：（1）在ZnNi/HZSM-5催化剂制备过程中，采用先浸渍Zn^2 后浸渍Ni^2 的方法可以获得性能好的催化剂；（2）混合C4烃在ZnNi/HZSM-5上的芳构化反应有最佳温度范围，在该温度范围内可以获得高的BTX的收率及选择性；（3）低的质量空速有利于芳构化反应，空速长高会因催化剂结焦而使BTX的收率及选择性下降；（4）在优化的反应温度520－540℃，质量空速1．0h^-1，以及常压非临氢的条件下连续反应6h，芳烃收率平均值为45％－56％，BTX收率达40％－46％，液态烃中芳烃含量达97％－99％。     

Fe-Co/SiO_2双金属催化剂上费托合成反应的研究

采用浸渍法制备Fe-Co/SiO2双金属催化剂,考察了不同反应温度、压力、空速下催化剂的反应性能。实验结果表明,在230~300℃的温度范围内,随反应温度升高,催化剂活性提高,甲烷选择性上升,水煤气变换程度逐渐增大,而C2~C4烯烃/烷烃比和C5+选择性下降;压力增加有利于反应活性的提高和重质烃的合成,当压力大于1.5MPa后,CO的转化率、水煤气变换程度、C5+选择性C2~C4烯烃/烷烃比变化不太明显;随空速增加,CO转化率下降,产物中低碳烃含量增加,说明高空速不利于重质烃的生成。XRD结果表明反应前催化剂主要成分为Co3O4和Fe2O3,反应后则为Fe-Co合金。     

FCC轻汽油临氢醚化催化剂反应特性的研究

在实验室以FCC汽油75℃前的轻馏分为原料，研究了负载贵金属具有二烯烃选择性加氢、双键异构化和叔碳烯烃与甲醇醚化反应三种功能的HSY型催化剂的反应性能。在反应温度60℃、氢分压1．5MPa、轻汽油与甲醇体积比10：l和混合进料的液体空速2．0h^-1的条件下，戊二烯的加氢转化率达100％，叔戊烯醚化转化率为68％左右，叔己烯醚化转化率为47％，非活性烯烃3—甲基—l—丁烯异构化为2—甲基—l—丁烯的异构化转化率达67％左右。临氢醚化后的轻汽油经催化蒸馏深度醚化，叔戊烯总转化率达到90．6％，叔己烯总转化率达61．5％，与重汽油调合后，汽油总烯烃含量降至29．6％，汽油辛烷值提高1．6—2．2个单位。     

纳米HZSM-5沸石催化剂上催化裂化轻汽油的芳构化

利用小型固定床加压反应器在纳米 HZSM-5沸石催化剂上进行了流化催化裂化(FCC)轻汽油(馏出温度小于等于85℃的馏分)的芳构化反应。实验结果表明,在反应温度为360～400℃、反应压力为1.0～3.0 MPa、重时空速为1.0～4.0 h~(-1)、V(H_2)∶V(原料)为260、反应时间48 h 的条件下,FCC 轻汽油中的 C_5~+烯烃转化率为39.11%～97.92%,产物中芳烃净增量为2.59%～19.05%,说明 FCC 轻汽油可在纳米 HZSM-5沸石催化剂上有效进行芳构化反应。汽油收率低和催化剂失活快是 FCC轻汽油在纳米 HZSM-5沸石催化剂上进行芳构化反应需要解决的两个主要问题。对纳米 HZSM-5沸石催化剂进行必要的改性处理及脱除原料中的二烯烃杂质呵以改进 FCC 轻汽油芳构化催化剂的性能。     

Ga改性HZSM-5催化剂芳构化性能的考察

以不同温度水热处理的纳米HZSM-5为母体制备了Ga/HZSM-5催化剂,并对该催化剂在FCC汽油芳构化上的性能进行考察。结果表明：以600 oC水热处理、硝酸洗涤的HZSM-5为母体制备的Ga/HZSM-5（GaHS600）的芳构化性能最优,当温度为480 oC,WHSV为1 h-1时,GaHS600上所得产品中芳烃和（C3+C4）体积分数分别为58.3%和7.6%。在本实验考察条件下,金属二次改性对Ga/HZSM-5芳构化性能的提高并无有利影响。     

La_2O_3对NiO/HMCM-56催化剂C_9~+重芳烃加氢脱烷基性能的影响

采用等体积浸渍法制备了NiO质量分数6%、La2O3添加量不同的La2O3-NiO/HMCM-56催化剂,考察了La2O3添加量和工艺条件对C9+重芳烃加氢脱烷基反应性能的影响,并采用XRD、H2-TPR、NH3-TPD和BET等技术对催化剂的物化性质进行了研究。实验结果表明,添加La2O3可以提高NiO在催化剂上的分散性,改变催化剂的酸性分布与酸量,改善了催化剂的加氢脱烷基性能;在实验范围内,随La2O3添加量的增加,加氢脱烷基反应的深度增加,C9+重芳烃转化率及苯、甲苯和二甲苯(统称BTX)收率增大,但二甲苯的选择性在La2O3添加量(质量分数)为3%时达到最大。采用La2O3添加量为3%的La2O3-NiO/HMCM-56催化剂,在460℃、3.0MPa、重量空速3.62h-1及V(H2)∶V(C9+)=1600的条件下,C+9重芳烃的转化率、BTX收率及BTX选择性分别为75.23%,63.36%,84.23%。     

Transformation of Cycloparaffin over Zeolite-Supported Metal Catalyst for Improving the Octane Number of Gasoline

In order to improve the octane number of gasoline, Ni/HZSM-5 and NiMo/HZSM-5 catalysts were prepared by impregnation method, and their activities for hydrocracking, hydroisomerization, and aromatization were investigated by the transformation of cylcohexane. The experimental results show that the conversion of cyclohexane is affected greatly by the reaction temperature. The production of methyl-cyclopentane is the result of the hydroisomerization of cyclohexane. The olefin distribution reveals that the hydrocracking reaction of cyclohexane over acidic zeolite catalyst probably obeys the dimolecular mechanism and the C₅ and C₇ olefins come from the cracking of the dimer of cyclohexane. The activities of the presulfided Ni/HZSM-5 and NiMo/HZSM-5 catalyst for the transformation of cyclohexane were evaluated and the product selectivities for two presulfided catalysts are similar to those obtained over reduced Ni/HZSM-5 catalyst.     

镍改性HZSM-5催化剂上甲醇芳构化反应性能的研究

采用浸渍法制备Ni改性的HZSM-5催化剂,采用BET,XRD,Py-FTIR,NH3-TPD等分析手段对催化剂进行表征。以纯甲醇为原料,在固定床微反装置上,考察不同Ni负载量改性HZSM-5催化剂对甲醇芳构化（MTA）反应性能的影响。实验结果表明：Ni的引入使催化剂产生了比较稳定的新L酸位;随着Ni负载量的增加,Ni/HZSM-5催化剂的总酸量增加,尤其是弱酸酸量;MTA反应的芳烃总收率随着Ni负载量的增加呈现先减少后增加然后又减少的趋势;Ni的引入可能改变了HZSM-5催化剂上MTA反应的路径,由氢转移芳构化向脱氢芳构化转变;生成的芳烃主要以C7~C9芳烃为主,C6和C10+芳烃相对较少;副产物甲烷和COx收率则随Ni负载量的增加而增加,这可能与Ni促进了甲醇的甲烷化反应有关。     

Kinetic Pecularities of Benzene Production from the Benzene-Toluene-Xylene Fraction of Pyrolysis Gasoline by Catalytic Hydrodealkylation at High Temperature

Hydrodealkylation (HDA) of the benzene-toluene-xylene (BTX) fraction of pyrolysis gasoline is an industrial route to produce benzene. Complicated kinetics of aromatic and nonaromatic hydrocarbon reactions has been experimentally investigated at the conditions of this process, employing a polyfunctional Al-Cr-KF catalyst with a high benzene selectivity, model feeds and BTX. The study reports effects of nonaromatic hydrocarbons on high temperature catalytic conversion of toluene. Above 525°C the process is found to be thermo-catalytic meaning that reactions take place on the catalyst surface and between catalyst pellets. The “pure” catalytic component of conversion is taken to be the difference between a thermo-catalytic and a thermal (i.e., without catalyst) run at the same conditions. Nonaromatic hydrocarbons substantially boost interpellet toluene HDA which is explained by a mechanism involving very fast decomposition of the nonaromatics into active radicals. The accompanying slight fall in catalytic toluene HDA, on the other hand, is considered to be due to nonaromatics and/or their hydrocracking products impeding toluene diffusion to the catalyst surface whose active centers they partially occupy. There is evidence that the C6-C8 nonaromatics of BTX influence the toluene conversion in the same manner as n-octane and cyclohexane. Benzene seems to render a small fall in surface conversion of toluene probably by inhibiting its diffusion. It apparently has no significant influence on nonaromatic hydrocracking or thermal toluene HDA. The hydrocracking products of the model feeds and BTX are 97-99 mol% C1-C4 alkanes and 1-3 mol% C2-C4 alkenes irrespective of the run type (i.e., thermal or catalytic). Moreover, given more time the hydrocracking reactions in the voids surpass those on the catalyst surface. Changing hydrogen:BTX molar ratio from 1.5 to 10 raises thermal (respectively “pure” catalytic) contribution significantly (respectively slightly) to conversions of toluene, C8 aromatics, n-octane, cyclohexane, and other C6-C8 nonaromatics.     

Influence of ZnO and P2O5 Content on Modified HZSM-5 on Aromatization of FCC Gasoline

Catalytic properties of different content of ZnO and P₂O₅ supported on HZSM-5 zeolites were studied in the conversion of FCC gasoline (75°C-120°C) into aromatic hydrocarbons with a temperature of 430°C, a liquid hourly space velocity of 1.0 hr^-1, and a pressure of 0.1 MPa. In the reaction, when the contents of ZnO and P₂O₅ are 2% and 4%, respectively, Zn-P/HZSM-5 showed the highest selectivity and activity to aromatic hydrocarbons and conversion of olefins. The content of aromatics in the liquid product and the yield of aromatics reached as high as 94.53%, 68.87%, and 51.74%, respectively.     

Transformation of Cycloparaffin over Zeolite-Supported Metal Catalyst for Improving the Octane Number of Gasoline

Abstract

In order to improve the octane number of gasoline, Ni/HZSM-5 and NiMo/HZSM-5 catalysts were prepared by impregnation method, and their activities for hydrocracking, hydroisomerization, and aromatization were investigated by the transformation of cylcohexane. The experimental results show that the conversion of cyclohexane is affected greatly by the reaction temperature. The production of methyl-cyclopentane is the result of the hydroisomerization of cyclohexane. The olefin distribution reveals that the hydrocracking reaction of cyclohexane over acidic zeolite catalyst probably obeys the dimolecular mechanism and the C₅ and C₇ olefins come from the cracking of the dimer of cyclohexane. The activities of the presulfided Ni/HZSM-5 and NiMo/HZSM-5 catalyst for the transformation of cyclohexane were evaluated and the product selectivities for two presulfided catalysts are similar to those obtained over reduced Ni/HZSM-5 catalyst.     

Kinetic Pecularities of Benzene Production from the Benzene–Toluene–Xylene Fraction of Pyrolysis Gasoline by Catalytic Hydrodealkylation at High Temperature

Abstract

Hydrodealkylation (HDA) of the benzene–toluene–xylene (BTX) fraction of pyrolysis gasoline is an industrial route to produce benzene. Complicated kinetics of aromatic and nonaromatic hydrocarbon reactions has been experimentally investigated at the conditions of this process, employing a polyfunctional Al–Cr–KF catalyst with a high benzene selectivity, model feeds and BTX. The study reports effects of nonaromatic hydrocarbons on high temperature catalytic conversion of toluene. Above 525°C the process is found to be thermo-catalytic meaning that reactions take place on the catalyst surface and between catalyst pellets. The “pure” catalytic component of conversion is taken to be the difference between a thermo-catalytic and a thermal (i.e., without catalyst) run at the same conditions. Nonaromatic hydrocarbons substantially boost interpellet toluene HDA which is explained by a mechanism involving very fast decomposition of the nonaromatics into active radicals. The accompanying slight fall in catalytic toluene HDA, on the other hand, is considered to be due to nonaromatics and/or their hydrocracking products impeding toluene diffusion to the catalyst surface whose active centers they partially occupy. There is evidence that the C6–C8 nonaromatics of BTX influence the toluene conversion in the same manner as n-octane and cyclohexane. Benzene seems to render a small fall in surface conversion of toluene probably by inhibiting its diffusion. It apparently has no significant influence on nonaromatic hydrocracking or thermal toluene HDA. The hydrocracking products of the model feeds and BTX are 97–99 mol% C1–C4 alkanes and 1–3 mol% C2–C4 alkenes irrespective of the run type (i.e., thermal or catalytic). Moreover, given more time the hydrocracking reactions in the voids surpass those on the catalyst surface. Changing hydrogen:BTX molar ratio from 1.5 to 10 raises thermal (respectively “pure” catalytic) contribution significantly (respectively slightly) to conversions of toluene, C8 aromatics, n-octane, cyclohexane, and other C6–C8 nonaromatics.     

ZSM-5/MCM-48复合分子筛基催化剂上甲醇制汽油反应工艺条件的研究

<正>甲醇转化为烃类液体燃料和化学品是当前替代石油技术研究的热点之一。早期由Mobil公司首先以提其出独了特甲的醇孔制道汽结油构(在MMTTG)G反技应术。中Z表S现M-出5良分好子筛的催化性能[1],但其强酸性导致油相产物中的芳烃含