FCC汽油加氢改质催化剂及改质工艺

研究开发出了适于FCC汽油加氢改质的选择性加氢脱硫催化剂和辛烷值恢复催化剂,并在300 mL绝热装置上,分别以全馏分FCC汽油或切割后的重馏分FCC汽油为原料,进行了FCC汽油加氢改质工艺的系统研究,结果表明：单独采用辛烷值恢复工艺或辛烷值恢复-选择性加氢脱硫组合工艺不能完全满足FCC汽油加氢改质的要求;而单独采用选择性加氢脱硫工艺或选择性加氢脱硫-辛烷值恢复组合工艺可以满足全馏分FCC汽油或切割后重馏分FCC汽油加氢改质的要求。将全馏分FCC汽油切割后进行加氢改质可以得到硫含量更低的改质产品或直接生产符合国Ⅳ标准的清洁汽油。     

催化裂化汽油在磷改性Ni/ZSM-5催化剂上的降烯烃工艺研究

采用浸渍法制备了Ni/ZSM-5和NiP/ZSM-5催化剂,其中Ni、P分别为HZSM-5质量的3％和0.5％。以锦州石化公司重油FCC汽油为原料,考察了助剂P加入前后催化剂的降烯烃反应性能。结果表明, NiP/ZSM-5催化剂具有较好的加氢降烯烃、异构化和芳构化活性,液体收率较高;考察了工艺条件对NiP/ZSM-5催化剂降烯烃反应的影响。在温度310 ℃、液时质量空速3 h^－1、氢油体积比300和反应压力2.5 MPa的最佳反应条件下,FCC汽油烯烃转化率、液体收率、产品中异构烷烃和芳烃的质量分数分别为72.9％、82.1％、45.84％和30.44％,而产品辛烷值不降低,达到了既降烯烃又不损失辛烷值的预期目的。     

ZSM-5/SAPO-5催化合成二芳基乙烷

对二甲苯与苯乙烯烷基化反应制二芳基乙烷反应体系进行考察。采用固定床反应器,在ZSM-5/SAPO-5复合分子筛催化剂下,研究了原料配比、反应温度、反应压力和空速对苯乙烯转化率和二芳基乙烷选择性的影响,确定了最佳工艺条件:苯乙烯与二甲苯物质的量比为1∶6,反应温度70℃,反应压力3.0 MPa,空速1.0 h~(-1),此条件下,苯乙烯转化率达100%,二芳基乙烷的选择性达80.48%。     

多级孔ZSM-5/SAPO-34复合分子筛制备及催化MTO性能研究

为制备性能更加优异的甲醇制烯烃（MTO）催化剂及进一步探究多级孔道对MTO催化反应的影响,采用柠檬酸溶液（CA）运用后处理方法对复合分子筛进行刻蚀,成功制备了具有多级孔道结构的ZSM-5/SAPO-34复合分子筛（CA-Z-S）。对复合分子筛的晶相、骨架、孔结构等理化性质进行了表征;将复合分子筛用于催化MTO反应,考察了复合分子筛的催化性能。表征结果表明,使用CA处理对ZSM-5/SAPO-34复合分子筛的形貌、结构会产生影响,使CA-Z-S具有更紧密的复合结构、适量的弱酸中心和多级孔道复合结构。催化测试结果表明,甲醇转化率达到100%时,CA-Z-S的寿命为1 200 min,较SAPO-34提高79%,较ZSM-5/SAPO-34提高30%;CA-Z-S对轻烯烃的选择性达到90.5%,较SAPO-34提高约3.7%。研究结果表明,利用CA对复合分子筛进行后处理,有利于复合分子筛催化MTO反应性能的提升。     

Effect of hydrothermal treatment temperature on FCC gasoline upgrading properties of the modified nanoscale ZSM-5 catalyst

Nanoscale HZSM-5 zeolite was hydrothermally treated with ammonia water at different temperatures and then loaded with La₂O₃ and ZnO. The parent and the modified nanoscale HZSM-5 catalysts were characterized by SEM, NH₃-TPD, IR and XRF. The performance of the modified HZSM-5 catalysts for FCC gasoline upgrading was evaluated in a fixed bed reactor in the presence of hydrogen. The results indicated that the modified catalyst which was hydrothermally treated at 400 °C exhibited excellent aromatization activity, isomerization activity and higher ability of reducing olefin content in FCC gasoline. Under the given reaction conditions, the olefin content in FCC gasoline could be decreased from 49.6 to 8.1 vol.%. The catalytic performance of the modified nanoscale ZSM-5 catalyst hardly changed within 300 h time on stream, and the research octane number (RON) of gasoline was preserved.     

Synthesis of ZSM-5 zeolite from expanded perlite and its catalytic performance in FCC gasoline aromatization

A hydrothermal synthesis method for ZSM-5 preparation was investigated by using expanded perlite as the only alumina source. The effect of crystallization conditions on ZSM-5 zeolite formation, such as temperature, time, pH, chemical composition of the reaction mixture, were studied. The samples were characterized by XRD, IR, SEM, XRF and BET surface area measurements. The ZSM-5 zeolite from expanded perlite showed better catalytic activity for the FCC gasoline aromatization reaction compared to ZSM-5 prepared by the standard method.     

催化裂化轻汽油在改性HZSM-5上的芳构化研究

采用同步浸渍法制备了w（ZnO）=2%、w(P₂O₅)=4%的ZnP/HZSM-5催化剂,以沸点75～120 ℃的催化裂化汽油馏分为原料,在小型固定床反应器上考察了工艺条件对该汽油馏分芳构化反应的影响。探讨了催化剂的失活机理。对汽油调合前后产品组成进行了对比。结果表明,在反应温度450 ℃、反应压力0.1 MPa和液空速1.0 h^-1的最佳反应条件下,原料中烯烃和烷烃转化率分别达到96.77%和88.94%,液相产品中烯烃质量分数及芳烃质量分数分别为6.79%和74.57%。再生后催化剂活性与新鲜催化剂相差无几,说明主要是由于积炭而导致失活。调合产品中烯烃质量分数较以前下降9个百分点,而芳烃质量分数上升12个百分点。     

Co-conversion of methanol and n-hexane into aromatics using intergrown ZSM-5/ZSM-11 as a catalyst

The conversion of n-hexane and methanol into value-added aromatic compounds is a promising method for their industrially relevant utilization. In this study, intergrown ZSM-5/ZSM-11 crystals were synthesized and their resulting catalytic performance was investigated and compared to those of the isolated ZSM-5 and ZSM-11 zeolites. The physicochemical properties of ZSM-5/ZSM-11 intergrown zeolite were analyzed using X-ray diffraction, N₂ isothermal adsorption-desorption, the temperature-programmed desorption of ammonium, scanning electron microscopy, Fourier transform infrared spectra of adsorbed pyridine, and nuclear magnetic resonance of ²⁷Al , and compared with those of the ZSM-5 and ZSM-11 zeolites. The catalytic performances of the materials were evaluated during the co-feeding reaction of methanol and n-hexane under the fixed bed conditions of 400°C, 0.5 MPa (N₂), methanol:꞉n-hexane=7꞉:3 (mass ratio), and weight hourly space velocity=1 h^–1 (methanol). Compared to the ZSM-5 and ZSM-11 zeolites, the ZSM-5/ZSM-11 zeolite exhibited the largest specific surface area, a unique crystal structure, moderate acidity, and suitable Brønsted/Lewis acid ratio. The evaluation results showed that ZSM-5/ZSM-11 catalyst exhibited better catalytic reactivity than the ZSM-5 and ZSM-11 catalysts in terms of methanol conversion rate, n-hexane conversion rate, and aromatic selectivity. The outstanding catalytic property of the intergrown ZSM-5/ZSM-11 was attributed to the enhanced diffusion associated with its unique crystal structure. The benefit of using zeolite intergrowth in the co-conversion of methanol and alkanes offers a novel route for future catalyst development.     

FCC汽油馏分在水热处理Zn/HZSM-5催化剂上的芳构化反应

制备了300 ℃、350 ℃、400 ℃和500 ℃不同水热处理温度下的Zn/HZSM-5催化剂，并用于FCC汽油馏分的芳构化反应。考察了水热处理温度对芳构化反应性能的影响，并与吡啶吸附红外光谱(FT-IR)相关联，研究了水热处理温度对催化剂表面酸性的影响。结果表明，水热处理Zn/HZSM-5的芳构化活性稳定性得以改善, 与未经水热处理的催化剂相比，400 ℃水热处理的Zn(2%)/HZSM-5催化剂芳构化反应36 h时，芳烃质量分数仍高达74.25%。随着水热处理温度的升高， B酸酸中心数在300～400 ℃变化不大，500 ℃显著减少，L酸酸中心数升高，400 ℃达到最大值后呈降低趋势，烯烃转化率、烷烃转化率和产品芳烃含量升高，水热处理400 ℃时均达到最大值，分别为83.62%、95.44%和92.23%，表明此时B酸中心和L酸中心比例协调性最佳。     

协同导向法合成ZSM-5/ZSM-11共生分子筛

使用四丁基铵(TBA~+)模板剂和Beta分子筛作晶种协同导向合成ZSM-5/ZSM-11共生分子筛。Beta分子筛晶种的加入扩大了ZSM-5/ZSM-11分子筛的合成相区,抑制了丝光沸石杂相的生成。研究了合成条件对共生结构中ZSM-5、ZSM-11的含量及分子筛晶体形貌的影响,发现相同条件下晶种添加量越大、合成碱度越小、投料硅铝比越高,共生结构中ZSM-11的含量越高,分子筛的晶粒尺寸越小。用X射线衍射(XRD)、扫描电镜(SEM)、N_2物理吸附(BET)、~(27)Al魔角旋转固体核磁(MAS-NMR)、NH_3程序升温脱附(NH_3-TPD)等对样品进行表征,发现ZSM-5/ZSM-11共生分子筛具有高的结晶度、丰富的孔结构、优良的Al的配位状态和强酸性,是具有潜在应用价值的优良催化剂。     

ZSM-5/SAPO-34复合分子筛的制备与甲醇芳构化性能研究

采用Na OH溶液处理法制备了介孔ZSM-5分子筛。采用包埋法合成了ZSM-5/SAPO-34复合介孔分子筛,并采用X射线衍射图谱(XRD)、电子扫描电镜(SEM)、氮吸附进行分析,在固定床反应器中进行了甲醇芳构化反应。研究结果表明,ZSM-5/SAPO-34复合分子筛孔径呈微孔和介孔多级孔分布,孔径和孔容均高于ZSM-5分子筛。当ZSM-5与SAPO-34分子筛的质量比为1∶2时,ZSM-5/SAPO-34复合分子筛具有较好的芳构化活性。在反应温度为475℃、反应压力0.5 MPa、空速(LHSV)1.2 h-1条件下,BTX(苯、甲苯和二甲苯)的收率可达30.8%。     

催化裂化汽油加氢改质催化剂的改进

针对催化裂化汽油加氢脱硫降烯烃组合工艺技术中,芳构化降烯烃改质催化剂M应用于重馏分汽油加氢时,存在因反应温度高而影响催化剂长周期运行及液体总收率等问题,对催化剂进行优化升级改进研究。结果表明,在M催化剂基础上,通过对HZSM-5分子筛原料改进及调变活性金属组分,研制出活性高和稳定性好的催化裂化重汽油芳构化降烯烃改质催化剂M-Ⅱ,与M催化剂相比,烯烃降低幅度相当时,芳烃增加1.5个百分点,研究法辛烷值提高0.8个单位。     

A novel catalyst system based on quadruple silicoaluminophosphate and aluminosilicate zeolites for FCC gasoline upgrading

To develop a novel catalyst system that has excellent olefin reduction capability for FCC gasoline without loss in octane number, different catalysts supported on multiple composite carriers consisting of SAPO-11, Hβ, HMOR and HZSM-5 were prepared and their catalytic performances for FCC gasoline upgrading were assessed in the present investigation. The pore structure and acidity of the catalysts were characterized by N₂ adsorption and pyridine adsorption FTIR, respectively. Based on the results obtained over the catalysts supported on binary-zeolite carriers (Hβ/HZSM-5, HMOR/HZSM-5 and SAPO-11/HZSM-5) using FCC gasoline as the feedstock, various multiple-zeolite supported catalysts were developed from different combinations of the binary-zeolite systems. It was found that the SAPO-11/HMOR/β/ZSM-5 quadruple composite zeolite supported catalyst gave higher liquid yield, improved gasoline RON, and lower coke deposit amount for the hydro-upgrading of FCC gasoline and thus can be considered as a potential catalyst system. A comprehensive analysis based on the catalytic activities and acidity measurements revealed that acid strength and acid type were two very important factors influencing hydroisomerization and aromatization activities, and the difference in catalyst acid strength determined which factor predominates.     

Synergisms between matrices and ZSM-5 in FCC gasoline non-hydrogenating upgrading catalysts

This article describes a novel non-hydrogenating FCC gasoline upgrading catalyst system consisting of a kaolin/γ-Al₂O₃ binary-matrix and an active component zeolite HZSM-5. Different catalysts made from the different combinations of HZSM-5 with the three matrices (two kaolins and γ-Al₂O₃) or their binary mixtures were prepared and their catalytic performances were assessed in a continuously flowing fixed-bed reactor using FCC gasoline as feedstock. The results showed that compared with the single-matrix based HZSM-5 catalysts, the binary-matrix based HZSM-5 catalysts had much better catalytic performance. The characterization results of the acidity, specific area and pore structure properties of the catalysts revealed that the synergisms between the matrices and HZSM-5 in the acidity and pore distribution of the binary-matrix based catalysts accounted for their improved catalytic performance. Our results demonstrated that the non-hydrogenating catalyst system developed in the present investigation can convert olefins in FCC gasoline into aromatics that have higher research octane number (RON) and thus has potential application for FCC gasoline upgrading because of its excellent olefin reduction ability and RON preservability.     

A novel method for enhancing on-stream stability of fluid catalytic cracking (FCC) gasoline hydro-upgrading catalyst: Post-treatment of HZSM-5 zeolite by combined steaming and citric acid leaching

This article describes a novel modification method consisting of steaming and subsequent citric acid leaching to finely tune acidity and pore structure of HZSM-5 zeolite and thereby to enhance the on-stream stability of the zeolite derived fluid catalytic cracking (FCC) gasoline hydro-upgrading catalyst. A series of dealuminated HZSM-5 zeolites and their derived catalysts were prepared and characterized by X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), ²⁷Al MAS NMR, nitrogen adsorption, temperature programmed desorption of ammonium (NH₃-TPD) and infrared (IR) spectroscopy of chemisorbed pyridine. The results showed that the citric acid leaching could preferentially remove the extra-framework Al (EFAl) species formed by steaming treatment and thus reopen the EFAl-blocked pore channels of the steamed zeolite. The steaming treatment at a suitable temperature and subsequent citric acid leaching not only decreased the strength of acid sites to a desirable degree but also increased the ratio of medium and strong Lewis acidity to medium and strong Brönsted acidity, both of which conferred the resulting catalyst with superior selectivity to aromatics, good hydroisomerization activity and gasoline research octane number (RON) preservability, as well as enhanced on-stream stability. The results fully demonstrated that the treatments by steaming and followed citric acid leaching can serve as an important method for adjusting the physicochemical properties of HZSM-5 zeolite.     

Organic template-free synthesis of ZSM-5/ZSM-11 co-crystalline zeolite

A series of ZSM-5/ZSM-11 co-crystalline zeolites with various compositions and morphologies were successfully synthesized via an organic template-free hydrothermal route and characterized by XRD, XRF, SEM, NMR and N₂ adsorption/desorption technologies. The effects of raw materials and batch composition were investigated systematically. Various silicon sources can be employed in the organic template-free synthesis of ZSM-5/ZSM-11 co-crystalline zeolite, however only a few types of aluminum sources are available. This organic template-free system is favorable to the aluminum-rich zeolite. With the increase of initial SiO₂/Al₂O₃ ratio, the ZSM-5 percentage in the ZSM-5/ZSM-11 co-crystalline zeolite increases as well as the crystal size, and especially the morphology of ZSM-5/ZSM-11 co-crystalline zeolite prepared from the colloidal silica-NaAlO₂ solution system changes gradually from nano-rod aggregation, micro-spindle to single hexagon and then to twinned hexagon crystals. Moreover, Na⁺ and OH⁻ in the initial materials can promote the nucleation of the ZSM-5/ZSM-11 co-crystalline zeolite significantly and are beneficial to the formation of crystals with relatively low length/width ratio, while K⁺ postpones the crystallization process seriously.     

轻烃低温芳构化制取高辛烷值汽油

考察了反应温度、空速和高径比条件对轻烃在分子筛催化剂上低温芳构化制取高辛烷值汽油性能的影响。结果表明,反应温度和空速对催化剂的催化性能有明显影响,提高反应温度有利于提高芳烃收率,增加进料空速,催化剂芳构化性能下降,芳烃二次反应也减少。在450 ℃、1.0 h^-1和高径比为6.0的条件下,此轻烃在ZSM-5催化剂作用下,可得到高辛烷值汽油,其初馏点为49 ℃,干点为203 ℃,烯烃质量分数为13.42%,芳烃质量分数为84.24%,辛烷值为101,可作汽油调和组分,也可直接作汽油使用。     

MCM-22/REHY催化剂上的FCC汽油改质

采用USY、REY和REHY分子筛为催化剂，在固定流化床上进行了催化裂化(FCC)汽油改性试验。结果表明，REHY催化剂表现出较好的芳构化和异构化性能。在反应温度400 ℃、液态汽油空速2 h^－1和反应时间15 min条件下，质量分数为5%的MCM-22对REHY催化剂起到很好的助催作用，液体收率达94.4%，而添加相同量的ZSM-5时，液体收率仅为90.46%；两者的异构化产物选择性和芳烃收率差别不大。考察了反应条件对5%MCM-22/REHY上反应的影响。     

NiMo/SAPO-11催化剂上正辛烷的异构化性能

以正辛烷为模型化合物,在连续微型反应装置上考察了金属Ni和Mo改性后的NiMo/SAPO-11催化剂的异构化和芳构化的反应性能,探讨了工艺条件对异构化产物分布的影响。结果表明:改性后的NiMo/SAPO-11催化剂在温度为400℃、压力为2.0MPa、液态空速为1.0h-1、VH2∶Vn.octane为400∶1的反应条件下反应性能较好,正辛烷的转化率、C5 液体产物收率,异构化和芳构化产物的选择性分别为69.80%、56.95%、79.73%、1.29%。     

催化裂化汽油馏分芳构化降烯烃研究

以75～120 ℃的FCC汽油馏分为原料，在连续固定床反应器上考察了Zn P/HZSM-5催化剂的芳构化反应性能，探讨了工艺条件对芳构化反应的影响以及工业化的可行性。结果表明，Zn-P/HZSM-5催化剂具有很高的活性、稳定性和芳烃选择性。在温度430 ℃、压力0.1 MPa、空速1 h^－1的反应条件下，得到了烯烃含量低、芳烃和异构烷烃较协调的汽油调合产品。