Hydro-conversion of 1-methyl naphthalene into (alkyl)benzenes over alumina-coated USY zeolite-supported NiMoS catalysts

Hydro-conversion reactions were carried out at 360 °C under 5 MPa of H₂ pressure to study ring opening reactions of 1-methyl naphthalene using NiMoS supported on γ-alumina and alumina-coated/mixed USY zeolites. The catalysts were characterized using N₂ BET, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), pyridine FT-IR, and high-resolution transmission electron microscopy (HR-TEM) to study the influence of morphological and acidic properties on hydrogenation (HYD) and hydrocracking (HC) reactions. NMACZ-2 (NiMoS supported on the minimum amount of alumina-coated USY zeolite) showed enhanced reactivity for HC and produced (alkyl)benzenes with the highest yield, of ca. 80%. By-products were tetralin, decalin and cyclo-paraffin species. The tetralin species produced using NMACZ-2 moved into the alumina-coated USY zeolite support before undergoing HYD to produce decalin species, which were rapidly and selectively hydro-cracked into (alkyl)benzenes. A large amount of decalin was produced through the HYD of tetralin without significant cracking, possibly due to the weak acid character of γ-alumina. Bulk phase Mo oxide species on NMAZ (physical mixture of alumina and USY zeolite), as well as deactivation of the catalysts due to coke formation over the naked zeolite surface, inhibited the ring opening of tetralin, decreasing the yield of (alkyl)benzene. Various morphologies, such as the MoS₂ structure and acidic characteristics of the catalysts, were crucial factors affecting the HC reactivity of 1-methyl naphthalene.     

改性Y分子筛加氢裂化催化剂耐氮性能的研究

采用水热处理法制备了两种改性Y型分子筛NTY和USY，并用含吡啶正庚烷和甲苯为模型化合物，对引入这两种分子筛制备的加氢裂化催化剂性能进行了考察，发现引入表面积大、二次孔多、结晶度高的NTY分子筛制备的加氢裂化催化剂，其耐氮性能明显优于USY分子筛制备的催化剂。     

Hydrocracking of petroleum gas oil over NiW/MCM-48-USY composite catalyst

MCM-48-USY composite materials were prepared by coating USY zeolite by a layer of MCM-48 mesoporous material at different meso/microporous ratios (SiO₂/USY ratios of 0.1, 0.2, 0.3, 0.4, 0.5) and used as support for nickel and tungsten. The NiW/MCM-48-USY catalysts were prepared using the incipient wetness method. The prepared catalysts were characterized by TPD-TGA acidity, TGA thermal stability, BET surface area, pore volume, pore size, XRD, SEM and TEM and then tested for hydrocracking of petroleum gas oil at reaction temperature of 450 °C, contact time of 90 min and catalyst to gas oil ratio of 0.04. In all prepared samples, the catalyst activity and properties were improved with increasing SiO₂/USY ratio and found that maximum values of a total conversion and liquid product (total distillate fuels) were obtained at SiO₂/USY ratio of 0.5. Finally, the obtained results from hydrocracking of gas oil over composite MCM-48-USY catalysts were compared with those obtained over physically mixed USY and MCM-48 catalysts.     

沸石孔结构对植物油催化裂化性能的影响

制备出硅铝比相近但介孔体积逐渐增加的超稳Y（USY）沸石，进而制备成微球状催化剂。本文在固定流化床装置上，考察了两种植物油的催化裂化性能。小桐子油的评价结果表明，催化剂中USY沸石的介孔体积越大，汽柴油收率越高；汽油族组成中烯烃收率越高，芳烃收率越低，汽油辛烷值和抗爆指数也越低；采用铵交换和水热改性制备介孔体积为0.142cm³/g的USY沸石催化剂的裂化产物中，汽柴油总收率为62.21%（质量分数），焦炭收率最低，汽油研究法辛烷值达到90.5；大豆油的催化裂化反应规律与小桐子油的一致，中等介孔催化剂裂化得到的汽油研究法辛烷值达到92.2。研究结果表明，采用催化裂化工艺，利用适当介孔的USY沸石催化剂，可以将植物油高效转化为车用轻质燃料，并且得到高辛烷值的汽油。     

不同铝源对SBA-15分子筛改性影响

为比较不同铝源对SBA-15分子筛改性的影响,以正硅酸乙酯为硅源,分别用异丙醇铝、氯化铝和硝酸铝对SBA-15分子筛进行改性, 运用XRD、N2等温吸附-脱附、SEM、 TEM和气相色谱对样品进行表征。将3种不同铝源改性SBA-15分子筛与USY分子筛复合制备加氢裂化催化剂,在固定床微型反应装置进行加氢裂化性能评价,结果表明,异丙醇铝在酸性条件下水解生成的Al(OH)^-₄更容易进入SiO₂骨架中,生成的产物异丙醇不影响铝离子的掺杂,由于异丙醇铝与正硅酸乙酯的水解速率一致,改性后所得材料孔分布更均一,规整性更高。将异丙醇铝对SBA-15分子筛改性后,与USY制备的复合分子筛催化剂用于正十二烷加氢裂化反应,选择性和转化率优于氯化铝和硝酸铝改性的分子筛。     

浸渍方法对Ni-W/Y-ASA催化剂加氢裂化性能的影响

以高比表面积无定形硅铝（ASA）和改性Y型分子筛（USY）为原料制备催化剂载体,分别采用传统浸渍法、铝溶胶浸渍法、USY粉体浸渍法和ASA粉体浸渍法制备Ni-W/Y-ASA催化剂。采用氮气吸附-脱附、扫描电镜（SEM）、氨气程序升温脱附（NH₃-TPD）、吸附吡啶原位红外（Py-IR）和颗粒强度测定仪等表征手段,探究不同的浸渍方法对催化剂的织构性质、形貌、酸性以及机械强度的影响,并将制备的催化剂应用于正癸烷的加氢裂化反应。结果表明,采用ASA粉体浸渍方法,因较多地保留了Ni-W/Y-ASA催化剂中USY粉体上的B酸性位,使催化剂具有最多的B酸含量,增强了催化剂的酸性质,进而提高了催化剂在以正癸烷为模型化合物的加氢裂化反应中的裂化活性。     

超稳Y分子筛脱铝改性的研究进展

超稳Y分子筛(USY)在石油化工催化领域应用广泛,尤其是作为加氢裂化和异构化反应的催化剂。随着工业化的发展,超稳Y分子筛逐渐满足不了催化剂的要求,达不到生产目的,而脱铝的超稳Y分子筛(DUSY)作为催化剂载体或活性组分的效果比母体USY分子筛要好,因此对脱铝改性的USY分子筛的研究引起关注。综述超稳Y分子筛的制备与脱铝改性方法的研究进展,改性方法包括水热法、化学法和水热-化学法,重点介绍化学脱铝改性对超稳Y分子筛的性质影响,展望超稳Y分子筛脱铝改性的发展方向。     

Hydrocracking of heavy oil using zeolites Y/Al-SBA-15 composites as catalyst supports

A series of Y/Al-SBA-15 composites were prepared by a two-step synthesis procedure in mild acidic medium. The materials were characterized by powder X-ray diffraction (XRD), N₂ sorption isotherms and TEM techniques. Catalytic cracking of cumene and 1,3,5-tri-isopropylbenzene was carried out as the probing reactions on these composites. The XRD results showed that these materials are composites of Al-SBA-15 and Y zeolite. N₂ sorption isotherms and TEM displayed that these composites were abundant in micropores and mesopores. At the same time, the mesopores may communicate with the␣micropores in some domains, which may result in the high catalytic activities of Y/Al-SBA-15 composites for the␣cracking of both small-molecule (cumene) and large-molecule (1,3,5-tri-isopropylbenzene) hydrocarbons. The existence of mesopores may also make the acid sites easily accessible for reactants. Catalysts of W–Ni supported on Y/Al-SBA-15 and modified Y zeolites with mesopores were prepared by impregnation method, and the hydrocracking of heavy oil was performed on these catalysts. The catalyst using zeolite Y/mesoporous Al-SBA-15 composites as support gave higher yield of diesel compared to the catalysts using modified zeolite Y as support. In addition, the higher aromatics potential of heavy naphtha and the significantly lower BMCI (U.S. Bureau of Correlation Index) of tail oil revealed Y/Al-SBA-15 composite catalyst possessed integrated performance in the hydrocracking of heavy oil. These results proved that the combination of Y zeolites and mesoporous Al-SBA-15 plays a great role in improving the performance of catalysts for hydrocracking heavy oils.     

Catalytic Activity of Y Zeolite Supported CeO2 Catalysts for Deep Oxidation of 1, 2-Dichloroethane (DCE)

Three Y zeolites supported CeO₂ catalysts (CeO₂/USY, CeO₂/HY, CeO₂/SSY) were prepared and used for deep oxidation of 1,2-dichloroethane (DCE) in low concentration (about 1,000 ppm). The catalysts were characterized by XRD, N₂ adsorption/desorption and H₂-TPR. The results showed that the catalytic activity of the supported CeO₂ catalysts was much higher than that of Y zeolites, in particular, CeO₂/USY exhibited the highest activity, T_98% values of DCE was about 270 °C. And the catalytic activity was strongly related to the interaction between CeO₂ and Y zeolites.     

Short overview on the application of metal-modified molecular sieves in selective hydrogenation of cinnamaldehyde

This article shortly overviews our recent work on the application of metal supported molecular sieve catalysts in liquid-phase hydrogenation of cinnamaldehyde. The topic covers catalyst deactivation, influence of the support, active metals as well as the influence of reaction conditions on catalytic performance. Acquired results demonstrate superior performance of microporous supports (zeolites) compared to mesoporous MCM-41, which was relatively unselective and less active. At optimised conditions, selectivity towards cinnamylalcohol of about 60–70% and reasonable activity were achieved.     

Coupled hydrogenation and ring opening of tetralin on potassium modified Pt/USY catalysts

Coupled hydrogenation and ring opening of tetralin (THN) on Pt/USY catalyst were performed on a high-pressure fixed-bed reactor. The effect of reaction temperature in range of 100–300 °C and the nature of the catalyst (metal and acid sites) on the catalytic performance were studied. The results indicated that the extent of hydrocracking, a sequential reaction of ring opening, should be reduced in order to maintain high yields of the ring opening products (ROP). Introduction of the Pt component accelerated the hydrogenation and ring opening of the THN significantly. It was also found to be an effective way to optimize the acid properties of the catalysts by introducing an appropriate amount of potassium to the catalyst, such that the strong acid sites of the catalysts were diminished, and a higher ROP yield could be obtained as a result of the inhibiting of the hydrocracking activity of the catalyst. When the yield of the C10 fractions could be maintained at 90 wt.%, then a maximal ROP yield of 35.6 wt.% could be obtained on a 0.5 wt.% Pt/USY catalyst loaded with 2.0 wt.% of K.     

Novel Ni2P/zeolite catalysts for naphthalene hydrocracking to BTX

Ni₂P catalysts supported on ZSM-5, Beta, and USY zeolites were prepared by temperature-programmed reduction (TPR), applied for the hydrocracking of naphthalene, and characterized by BET, CO uptake, NH₃-TPD, TEM, X-ray diffraction (XRD), and extended X-ray absorption fine structure (EXAFS). The catalytic activity was tested at 673 K and 3.0 MPa in a three-phase fixed bed reactor for hydrocracking of naphthalene. The Ni₂P/Beta exhibited best activity with a naphthalene conversion of 99%, and a BTX yield of 94.4%. Well-dispersed Ni₂P particles combined with moderate acidity and porosity of zeolite Beta contributed to the enhanced hydrocracking activity of naphthalene into BTX.     

Cu/SSZ-13催化剂脱硝活性中心与催化性能构效关系的研究

NH₃选择性催化还原NO_x（NH₃-SCR）是目前最有应用前景的柴油车尾气净化技术,该技术的核心是开发具备优异催化性能的催化剂。以具有菱沸石（chabazite,CHA）结构的小孔分子筛SSZ-13为载体制备的Cu/SSZ-13催化剂,因具有优异的催化性能和水热稳定性能而受到广泛关注。制备了系列Cu_x/SSZ-13催化剂,并通过CO原位漫反射红外光谱（DRIFT）和H₂-TPR等方法能够确定具有高催化活性的铜离子在SSZ-13分子筛上的落位和存在状态。CO红外吸附实验发现,采用Cu(NO₃)₂水溶液离子交换法制备的Cu/SSZ-13催化剂上存在多种落位的Cu⁺活性中心。在较低的Cu⁺交换度条件下,Cu⁺优先落位于SSZ-13分子筛的八元环位置,随着交换度的提高,Cu⁺开始落位于SSZ-13分子筛双六元环的位置。H₂-TPR结果表明Cu_x/SSZ-13催化剂上也存在大量落位在八元环位置不稳定的Cu²⁺,这些Cu²⁺很容易被还原为Cu⁺。Cu_x/SSZ-13催化剂经800℃水蒸气连续老化16 h,分子筛骨架崩塌程度随着Cu含量的增加而提高,骨架铝的脱除,导致Cu物种发生团聚,而第二金属Ce元素的引入能够在一定程度上提高Cu/SSZ-13的水热稳定性。催化剂构效关系研究表明,具有一定量稳定存在的Cu⁺,并且拥有大量不稳定存在Cu²⁺的催化剂具有较宽温度范围的脱硝性能。     

Selective preparation of light aromatic hydrocarbons from catalytic fast pyrolysis vapors of coal tar asphaltene over transition metal ion modified zeolites

The catalytic cracking of coal tar asphaltene (CTA) pyrolysis vapors was carried out over transition met-alion modified zeolites to promote the generation of light aromatic hydrocarbons (L-ArHs) in a pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) micro-reactor system.The effects of ultra stable Y(USY),Co/USY and Mo/USY on the selectivity and yield of L-ArHs products and the extent of deoxygena-tion (Edeoxygenation),lightweight (Elightweight) from CTA pyrolysis volatiles were investigated.Results showed that the yields of L-ArHs are mainly controlled by the acid sites and specific surface area of the catalysts,while the deoxygenation effect is determined by theirs pore size.The Elightweight of CTA pyrolysis volatiles over USY is 9.65％,while the Edeoxygenation of CTA pyrolysis volatiles over Mo/USY reaches 20.85％.Additionally,the modified zeolites (Mo/USY and Co/USY) exhibit better performance than USY on L-ArHs production,owing to the synergistic effect of metal ions (Mo,Co) and acid sites of USY.Compared with the non-catalytic fast pyrolysis of CTA,the total yield of L-ArHs obtained over USY (4032 mg·kg-1),Co/USY (4363 mg·kg-1) and Mo/USY (4953 mg·kg-1) were increased by 27.03％,38.19％ and 54.78％,respectively.Furthermore,the possible catalytic conversion mechanism of transition metal ion (Co and Mo) modified zeolites was proposed based on the distribution of products and the characterizations of catalysts.     

A comparative activity study of a new ultra-dispersed catalyst system for a hydrocracking/hydrotreating technology using vacuum residue oil: Merey/Mesa

Ultra-dispersed catalysts give an improvement over the main reactions activity by having a low deactivation rate. They provide as well other advantages like a diminution in the catalysts metal concentration, a reduction in contaminants and also these catalysts can be used in almost every area where heterogeneous catalysts are used. Catalysts synthesis optimization is important to improve process recovery, especially in hydrocracking/hydrotreating processes, where feedstock is vacuum residue. Here, we have evaluated the catalytic performance of two molybdenum–nickel catalysts prepared using different emulsion formulation, named E-T (base catalyst) and AT-48 (new catalyst). Our results showed that, the percentage of converted products for VR 500 °C⁺, asphaltenes and microcarbon are comparable for both E-T and AT-48 catalysts, despite the fact that for the latter a lower molybdenum concentration was used. In addition, post-catalytic particles analyses using SEM and TEM techniques demonstrated that AT-48 catalyst showed a non-aggregated and homogeneous narrower distribution of metallic particles than E-T one. The lower average particle size distribution is related to the improvement of the liquid product yields for the hydroconversion of Mery/Mesa VR using the AT-48 catalyst.     

A Comparative Study of Hydroxyapatite- and Alumina-Based Catalysts in Dry Reforming of Methane

The dry reforming of methane over hydroxyapatite- and alumina/magnesia (commercial Pural MG 30)-supported nickel catalysts was investigated. The catalytic performance of the catalysts prepared with fresh supports highly depended on the basicity, the metal-support interaction, and the metal particle size. Calcination of the supports at 1200 °C for 5 h made the catalysts less active because of specific surface area reduction and basicity destruction. However, this treatment allowed avoiding any further catalyst deactivation by thermal sintering and maintained excellent catalytic stability over 300 h of time-on-stream. These tests under simulated industrial conditions (high contact time and long time-on-stream) showed the competitiveness of the prepared catalysts in this important catalytic process.     

Composites as cracking catalysts in the production of biofuel from palm oil: Deactivation studies

Composite catalysts HZSM-5/alumina (CZA) and Al-MCM-41/alumina (CMA) were synthesized and tested for their catalytic cracking activity in the production of biofuel from palm oil. Both composite catalysts were characterized for their structure, acidity and surface morphology. The addition of alumina in the composite catalysts improved their hydrothermal stability due to the changes in the surface morphology. The deactivation of the catalysts was studied by obtaining time on stream data by varying the palm oil to catalyst ratio of 8–16. The deactivation data were analyzed using different activity models and the deactivation parameters were determined.     

固体酸催化淀粉一锅法制备果葡糖浆的研究

研究了几种负载型固体酸催化剂催化淀粉转化为果葡糖浆的催化效果,其中,超稳Y型分子筛（USY）负载硫酸制备得到的SO₄^2-/USY可以作为双功能催化剂,既催化淀粉水解为葡萄糖,又使葡萄糖异构为果糖,实现了淀粉一锅法制备果葡糖浆的工艺途径,具有良好的催化效果。对催化剂的制备条件进行优化,发现较佳的制备条件为1.5 mol/L H₂SO₄和550℃的焙烧温度。以此为催化剂对反应条件进行优化,获得较佳的反应条件是5%淀粉（淀粉/水）、催化剂用量为淀粉质量的30%、反应温度为150℃、反应时间为1 h、转速400 r/min,得到的果葡糖浆得率为86.18%,含58.34%的葡萄糖和27.84%的果糖。对催化剂进行物理吸附表征,发现USY具有较高的比表面积和孔隙度,通过浸渍焙烧过程能有效使硫酸通过键合作用吸附在USY表面上。对催化剂进行NH₃程序升温脱附和元素分析表征发现,催化剂的重复使用活性降低与含碳有机质沉积和催化活性中心的SO₄^2-流失有关。通过简单的焙烧（除去表面积碳）和硫酸中浸渍活化（增加SO₄^2-）的催化剂再生方法,可以有效地恢复SO₄^2-/USY的催化活性。     

Nickel Activation for Hydrogenolysis Reaction on USY Zeolite

The effects of the SAR (14 and 38) and of the methodology of introduction of nickel (wetness impregnation and ion exchange) on catalyst activation were investigated in Ni/USY model catalysts submitted to two activation treatments: reduction (A) and reduction/calcination/reduction, successively (B). the catalysts prepared by wetness impregnation, a marked increase in the catalytic activity after treatment B was observed. On the basis of the catalyst efficiency toward ethane hydrogenolysis, the lower SAR catalyst presents a threefold higher activity. On the contrary, the catalysts prepared by ion exchange, as well as a model catalyst prepared by wetness impregnation over a USY exhaustively exchanged with nickel ions, do not present measurable increasing of the catalytic activity under the same activation conditions. Monitoring the catalyst activation by EXAFS indicates the formation of nickel clusters in the impregnated catalysts after activation treatment B, which should be responsible for the high catalytic activity. However, TEM images reveal a bimodal particle size distribution, with large (ca. 20 nm) and small nickel particles. Temperature-programmed reduction performed under the same conditions of catalyst activation suggests that only the small nickel particles are activated under the experimental conditions adopted in this work.     

Pd-β/MCM-41复合分子筛加氢裂解废食用油性能研究

以碱处理β沸石作为硅铝源,以CTAB为模板剂,合成了β/MCM-41介孔-微孔复合分子筛,以其为载体制备Pd-β/MCM-41复合分子筛催化剂,利用XRD、N₂吸附-脱附、NH₃-TPD和XRF等技术对其进行了表征,并与γ-Al₂O₃、USY、ZSM-5等载体制备的催化剂比较了废食用油加氢裂解活性。结果表明：β/MCM-41复合分子筛同时具备β沸石和MCM-41分子筛的结构,β/MCM-41为载体时,Pd-β/MCM-41催化剂具有适宜的中强酸性中心,适宜的孔道分布结构,催化剂加氢裂解废食用油的活性最高。此外还考察了催化剂制备条件对废食用油加氢裂解反应的影响,结果表明：采用离子交换法制备负载量2%的Pd-β/MCM-41复合分子筛催化剂、焙烧温度为500 ℃时,催化剂对废食用油加氢裂解的效果最好。此时,原料油的转化率可以达到85.9%,生物汽油的收率可以达到16.4%,生物柴油的收率达到17.8%,且此催化剂水热稳定性较好,再生性能良好,工业化应用前景较好。