The catalytic properties of transition metal sulfides synthesized from Anderson-type heteropoly compounds in hydrogenation, hydrodesulfurization, and hydrodenitrogenation reactions

XMo₆HPC/Al₂O₃ catalysts based on Anderson-type heteropoly compounds (HPCs) with heteroatoms X = Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, and Al were synthesized. The catalytic properties of the prepared samples were studied in naphthalene hydrogenation, dibenzothiophene hydrodesulfurization, and quinoline hydrodenitrogenation. The highest activity was exhibited by the catalysts with X = Co and Ni; the lowest, with X = Cu. It was found that dibenzothiophene hydrodesulfurization and naphthalene hydrogenation occur on different active sites, whereas the sites of the hydrogenation of naphthalene and dibenzothiophene have a similar nature. Quinoline (at a nitrogen content of 100 ppm) had a different effect on the catalytic properties: it inhibited the hydrogenation of dibenzothiophene and naphthalene, but promoted the desulfurization of dibenzothiophene.     

Co掺杂对CuO/ CeO2-Co3O4优先氧化CO催化性能的影响

采用共沉淀-浸渍法制备了一系列不同Ce/Co物质的量比的CeO₂-Co₃O₄载体和CuO负载量(质量分数)为7% 的CuO/CeO₂-Co₃O₄催化剂,考察了它们在富氢气氛中对CO的优先氧化性能。采用BET、XRD、H₂-TPR等对催化剂进行了表征。测试结果表明:Ce/(Co+Ce)物质的量比为0.9时,CuO/ CeO₂-Co₃O₄催化剂活性最好。少量的Co掺杂有利于提高催化剂的比表面积和铜物种在载体上的分散,少量的Co进入了CeO₂的晶格,增强了钴铈相互作用,进而提高了载体的氧化还原性能。      

Effect of surface modification of the support of hydrotreating catalysts with transition metal oxides (sulfides) on their catalytic properties

CoMo/MeO _x (S _y )/Al₂O₃ catalysts have been synthesized on supports modified with oxides (sulfides) of transition metals (Co, Ni, Mn, and Zn) using decamolybdodicobaltic heteropoly acid H₆[Co₂Mo₁₀O₃₈H₄]. A correlation between the activity of the catalysts and the ability of transition metal sulfides to accumulate molecular hydrogen has been found in the hydrodesulfurization (HDS) of dibenzothiophene (DBT) and in the hydrotreating of the diesel fraction. It has been shown that the presence on the surface of Al₂O₃ of sulfides (NiS _x , CoS _x ) capable of activating hydrogen has a positive effect on the activity of the supported catalysts. It has been found that the hydrogen spillover effect, which was studied in a range of 300–350°C, contributes to an increase in the hydrogenating function of the catalyst systems.     

Co-hydrotreating of straight-run diesel fraction and vegetable oil on Co(Ni)-PMo/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> catalysts

The process of co-hydrotreatment of straight-run diesel fraction (DF) and vegetable oil (VO) on Co(Ni)-PMo/Al₂O₃ catalysts prepared from H₃PMo₁₂O₄₀ and cobalt (nickel) citrate has been studied. It has been shown that under conditions close to those in the industry, the complete conversion of fatty acid triglycerides (FATG) is achieved on the catalysts of both types to give an ultraclean hydrotreating product in a 97% yield and a cetane number of 5 points above that of the hydrotreating product of the DF alone. The degree of hydrodesulfurization (HDS) is reduced more significantly on the Co-PMo/Al₂O₃ catalyst than in the case of Ni-PMo/Al₂O₃. The catalysts are more susceptible to deactivation in the hydrotreating of the blended feedstock containing VO. The Co-PMo/Al₂O₃ sample is less stable than Ni-PMo/Al₂O₃. Examination of the spent catalysts by transmission electron microscopy has shown that the average particle length of the active phase of Co-PMo/Al₂O₃ increases, whereas this increment for Ni-PMo/Al₂O₃ is insignificant, indicating higher stability of particles of the NiMoS phase. Thus, the co-hydrotreating of petroleum fractions and vegetable oil is more reasonable to carry out on NiMo/Al₂O₃ catalysts.     

Effect of Vanadium Introduction on the Activity of NiMo/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> Catalysts in the Hydrotreating of Diesel Fractions

The influence of the introduction of V₂O₅ into NiMo/Al₂O₃ catalysts on their activity in hydrodesulfurization (HDS) and hydrogenation reactions of the components of petroleum fractions has been studied. The activity of the synthesized catalysts has been determined in the straight-run diesel and light coker gas oil hydrotreating processes in a flow-through unit under hydrogen pressure. The most active catalyst for HDS and hydrogenation of polycyclic aromatic hydrocarbons has been synthesized using VMo₁₂ heteropoly compounds: the activity increases by 6–10 and 11–13 wt % in HDS and PAH hydrogenation, respectively, at different temperatures. It has been shown that the activity of the regenerated catalyst further impregnated with the vanadium compound in HDS and PAH hydrogenation increases by 2–5 rel. %, as compared to the regenerated catalyst.     

Hydrogen treatment of vacuum gas oil on sulfide catalysts: Influence of composition and porous structure

Three samples of γ-Al₂O₃ with different textural characteristics have been synthesized from AlOOH powders (Sasol). Ni(Co)Mo/Al₂O₃ catalysts have been prepared by single impregnation of the γ-Al₂O₃ samples with solutions of active ingredients. The morphology of the active phase of the sulfided samples has been studied by high-resolution transmission electron microscopy. The catalytic activity has been measured with the use of vacuum gas oil (VGO) as a feedstock at temperatures of 360, 390 and 420°C. After catalytic activity measurements, the catalysts have been investigated by means of differential thermal and thermographic analysis (DTA-TGA). Textural characteristics of the catalysts in the oxide and sulfide forms have been determined, including those after the measurement of activity in VGO hydrotreating. The textural characteristics of the samples have been shown to correlate with the extent of the hydrogenation reactions of aromatic hydrocarbons and hydrodesulfurization. The highest hydrogenating and hydrodesulfurizing activity has been displayed by the sample on the support with the largest specific surface area and the smallest effective pore radius.     

Selective Oxidation of Cyclohexane Using a Co-M/Al2O3 Catalyst without Additives

Abstract

Without any organic solvent or activator, the selective oxidation of cyclohexane with air to afford cyclohexanol and cyclohexanone was investigated over Co/Al₂O₃ and Co-M/Al₂O₃ (M = Cu, Zn, and Ni) catalysts prepared by sol-gel method. The activity of the catalysts decreases in the following order: Co-Ni/Al₂O₃ > Co/Al₂O₃ > Co-Zn/Al₂O₃ > Co-Cu/Al₂O₃. The optimum contents of cobalt and nickel are 4.0 wt% and 3.0 wt% in Co-Ni/Al₂O₃ catalyst, respectively. The best result was obtained over Co-Ni/Al₂O₃ catalyst with a conversion of 9.9% and a selectivity of 94.6% and the ratio of cyclohexanone to cyclohexanol of 2.8 when the reaction was carried out at 443 K for 120 min under 4.5 MPa, and catalytic activity did not change after five consecutive reactions.     

负载型氮化物催化剂的性质及加氢精制性能

 采用N₂/H₂程序升温还原法制备了非负载型氮化钼(Mo₂N)和氮化镍钼(Ni₂Mo₃N)催化剂，并以Al₂O₃为载体制备了负载型氮化钼(Mo₂N/Al₂O₃)和氮化镍钼(Ni₂Mo₃N/Al₂O₃)催化剂。采用XRD、BET、H₂-TPR和NH₃-TPD等方法对制备的氮化物催化剂的性质进行了研究，并分别以含2%（质量分数，下同）噻吩和10%四氢萘的环己烷溶液为含硫、含芳烃的柴油模型化合物，考察了制备的负载型氮化物的加氢脱硫（HDS）及加氢脱芳烃（HAD）性能。结果表明，以金属氧化物为前驱物，采用N₂/H₂程序升温还原法制得的氮化钼为Mo₂N(γ型)、氮化镍钼为Ni₂Mo₃N；经钝化处理后，氮化物表面形成了金属氧化物保护层，其中Mo₂N/Al₂O₃和Ni₂Mo₃N/Al₂O₃表面氧化层的还原温度分别为350和300℃。Mo₂N/Al₂O₃和Ni₂Mo₃N/Al₂O₃催化剂的表面酸性以弱酸为主；二者均表现出较好的HDS性能，但Mo₂N/Al₂O₃的HDA性能很差，而Ni₂Mo₃N/Al₂O₃的HDA性能较Mo₂N/Al₂O₃有一定程度的提高，说明镍钼共存有利于提高金属组分的分散性及催化剂的加氢饱和性能。     

临氢条件下NiMoS/γ-Al2O3催化辛烯-1与H2S的反应

 在高压反应釜中临氢条件下研究了NiMoS/γ-Al₂O₃催化辛烯-1与H₂S的反应,考察了反应温度、H₂S含量和烯烃体积分数对反应产物的影响,对反应产物进行GC-MS分析,探讨了辛烯-1与H₂S的反应机理。结果表明,辛烯-1与H₂S反应主要生成硫醇类和硫醚类化合物,辛烯-1本身还会发生加氢饱和反应和双键迁移异构化反应。随着反应温度升高,反应产物中的硫醇硫和总硫的量均逐渐减少,同时促进了辛烯-1的加氢饱和反应。反应体系中H₂S的含量越高,产物中硫醇硫和硫醚硫的含量越大;而且H₂S还会促进辛烯-1的双键迁移异构化反应,抑制辛烯-1的加氢饱和反应。随着反应体系中辛烯-1体积分数增大,产物中总硫的含量不断增大,而硫醇硫的含量先增大后减小,此外,辛烯-1的异构化产物和加氢饱和产物也会随之不断增多。     

Synthesis of carbon nanotubes by CCVD of natural gas using hydrotreating catalysts

Carbon nanotubes have been successfully synthesized using the catalytic chemical vapor deposition (CCVD) technique over typical refining hydrotreating catalysts (hydrodesulfurization and hydrodenitrogenation) containing Ni–Mo and Co–Mo supported on Al₂O₃ catalysts at 700°C in a fixed bed horizontal reactor using natural gas as a carbon source. The catalysts and the as-grown CNTs were characterized by transmission electron microscopy, HRTEM, X-ray diffraction patterns, EDX and TGA–DTG. The obtained data clarified that the Ni–Mo catalyst gives higher yield, higher purity and selectivity for CNTs compared to Co–Mo catalyst. XRD, TEM and TGA reveal also that the Ni–Mo catalyst produces mostly CNTs with different diameters whereas the Co–Mo catalyst produces largely amorphous carbon.     

煅烧还原一步制备Ni基催化剂及在CH4-CO2重整反应中的应用

采用大豆油研磨法制备了Ni/C-SiO_2系列催化剂,并用于CH_4-CO_2重整反应。通过XRD、TG-DTG、BET、H_2-TPR、CO_2-TPD等对催化剂进行了物理性能表征,利用固定床连续反应对催化剂进行了催化性能测试。结果表明,研磨法制得的催化剂前驱体在惰性气氛N2中煅烧后,催化剂上的镍元素全部转变成了Ni~0,实现了煅烧还原一步制备中孔Ni基催化剂。CH_4-CO_2重整反应后的催化剂上存在两种炭,一种是催化剂制备时残留的碳源炭,另一种是重整反应过程中产生的可致催化剂失活的积炭。考察了助剂CeO_2、ZrO_2、La_2O_3对催化剂性能的影响,结果表明,与Ni/C-SiO_2催化剂相比,Ni-CeO_2/C-SiO_2、Ni-ZrO_2/C-SiO_2、Ni-La_2O_3/C-SiO_2催化剂中Ni~0的粒径降低了,Ni-CeO_2/C-SiO_2、Ni-La_2O_3/C-SiO_2催化剂的反应活性提高了,反应后Ni-ZrO_2/C-SiO_2、Ni-La_2O_3/C-SiO_2催化剂上的积炭减少了。助剂La_2O_3不仅提高了催化剂活性,而且降低了催化剂上的积炭量,使用Ni-La_2O_3/C-SiO_2催化剂进行CH_4-CO_2重整反应,总碳转化率达到了52%。     

孔径双峰分布γ-Al2O3负载NiMoP催化剂的制备及对蜡油加氢催化性能

在氢氧化铝干胶挤条成型时,调节纳米炭黑的加入量和水/粉质量比,制备了孔径呈双峰分布、具有较大孔容和比表面积的γ-Al2O3载体。当炭黑加入质量分数为13%、水/粉质量比1.15时,制备的孔径呈双峰分布的γ-Al2O3载体的孔容为0.80mL/g、比表面积为309m2/g,4～10nm和10～15nm孔径分别占总孔容50.8%和35.1%(体积分数),采用该载体制备的NiMoP/γ-Al2O3催化剂的孔径呈明显的双峰分布。在反应温度370℃、氢分压10MPa、氢/油体积比700、体积空速1.5h-1的条件下,制备的NiMoP/γ-Al2O3催化剂可使减压和焦化混合蜡油的硫质量分数由25600μg/g降至2070μg/g,脱硫率为91.9%,而参比催化剂仅可使减压和焦化混合蜡油硫质量分数降至3450μg/g,脱硫率为86.5%。     

Hydrogen production by catalytic methane decomposition over Ni,Co, and Ni-Co/Al2O3 catalyst

Hydrogen is a chief source of energy. Catalytic decomposition produces hydrogen and carbon. In this work, x%M/Al₂O₃ (where M is Ni, Co and combined Ni-Co, and x is 10%, 15%, and 30%) has been successfully employed as a catalyst. The effect of activation temperature and active metal type and loading on catalyst perfomance was investigated. The catalysts were characterized with BET, XRD, TPO, TPR, TEM, XPS, and Raman. The results displayed that the 30%Co/Al₂O₃ catalyst activated at 500°C provided the greatest catalytic performance toward methane conversion. 30%Co/Al₂O₃ catalyst activated at 500°C formed amorphous carbon.     

NiV/Al_2O_3催化剂的渣油加氢活性研究

以孔饱和浸渍法制备不同Ni/(Ni+V)原子比的NiV/Al2O3催化剂,并对催化剂进行拉曼光谱和H2-程序升温还原(H2-TPR)表征。以科威特常压渣油为原料,考察不同Ni/(Ni+V)原子比的NiV/Al2O3催化剂的渣油加氢脱金属和脱硫活性。研究结果表明:Ni可促进V的聚集,减弱V与载体间的相互作用;Ni与V具有协同作用,Ni/(Ni+V)原子比为0.25时,催化剂的渣油加氢脱金属活性明显高于其它Ni/(Ni+V)原子比的催化剂,渣油加氢脱硫活性略高于其它Ni/(Ni+V)原子比的催化剂。     

An Investigation of the Deactivation Behavior of Industrial Mo/Al2O3 and Ni-Mo/Al2O3 Catalysts in Hydrotreating Kuwait Atmospheric Residue

Abstract

The catalyst system for fixed-bed residue hydrotreating processes usually consists of different types of catalysts designed to promote hydrodemetallation (HDM), hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) reactions to desired levels. Overall catalyst life is determined by the performance of the individual catalysts in the different reactors. Therefore, information about the activity, stability, selectivity, and deactivation behavior of the individual catalyst is highly desirable to design improved catalysts that can prolong catalyst life, increase stream efficiency, and improve process economics. In the present work, residue hydrotreating experiments were conducted on two types of industrial hydrotreating catalysts, namely Mo/Al₂O₃ and Ni-Mo/Al₂O₃, that have been used as HDM and HDS catalysts, respectively, in an industrial ARDS process. The primary objective of the study was to compare the deactivation behavior of both types of catalyst. The characterization of the used catalysts by elemental analysis, surface area, pore volume, and pore size measurements along with TPO-MS, ¹³C NMR, and electron microprobe analysis showed significant differences in the nature of the coke and metal deposits on the two types of catalysts. The role of initial coking, the relative importance of the coke, and metal depositions on the deactivation of the two types of catalyst are discussed.     

ZSM-5/MCM-41介孔硅铝分子筛担载Pd和Pt制备加氢脱硫催化剂

将ZSM-5溶于偏硅酸钠水溶液,以十六烷基三甲基溴化铵作模板剂,用水热合成法自组装合成了具有较强酸性和不同SiO₂/Al₂O₃摩尔比(n(SiO₂)/n(Al₂O₃))的ZSM-5/MCM-41介孔硅铝分子筛（记为ZM(x),x=n(SiO₂)/n(Al₂O₃)）。以二苯并噻吩（DBT）质量分数为0.8%的十氢萘溶液为模型化合物,考察了Si-MCM-41和ZM(x)担载的Pd和Pt催化剂催化加氢脱硫（HDS）反应的活性。结果表明,担载Pt和Pd不会破坏ZM(x)的介孔结构;DBT在Pd催化剂上主要通过加氢路径脱硫,而在Pt催化剂上则直接脱硫和加氢2条反应路径并重;Si-MCM-41为载体的催化剂HDS活性较低并且失活较快,以ZM(x)为载体的Pd和Pt催化剂加氢活性、加氢脱硫活性、加氢裂化活性及稳定性都有显著提高;ZM(x)担载的Pt和Pd催化剂催化HDS反应的活性可能与其活性组分分散度以及载体的B酸和L酸比例（B/L）有关,具有较好的活性组分分散度和较高B/L比例的ZM(60)担载的Pd和Pt催化剂表现出最佳的加氢脱硫活性和稳定性。     

Sulfuration Pretreatment of Ni/Al2O3 Catalyst to Remove Butadiene in FCC C4 Fraction

Abstract

The Ni-based catalysts have more advantages than the most widely used Pd-based catalysts in selective hydrogenating of the butadiene in fluid catalytic cracking (FCC) C₄ fraction. But the selectivity and stability of the Ni-based catalysts aren't good. The sulfuration pretreatment is an effective process to improve the performance of the Ni/Al₂O₃ catalysts. The sulfuration conditions of the Ni/Al₂O₃ catalyst have been studied in this article. The results showed the fittest conditions are that the catalyst was in-situ presulfurized for 60 min by the solution of S concentration 0.07 mol/L. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis indicated that the presulfurization declined the Ni crystal dimension.     

CA和EDTA对Co-Mo-P/TiO2-γ-Al2O3选择性加氢脱硫催化剂性能的影响

 制备了添加螯合剂柠檬酸(CA)和乙二胺四乙酸(EDTA)的Co-Mo-P/TiO₂-γ-Al₂O₃加氢脱硫催化剂,并对其进行了BET、SEM和H₂-TPR表征。以FCC汽油重馏分为原料,考察了螯合剂对Co-Mo-P/TiO₂-γ-Al₂O₃催化剂选择性加氢脱硫性能的影响。结果表明,添加CA或EDTA均可不同程度地提高Co-Mo-P/TiO₂-γ-Al₂O₃催化剂的比表面积;适量的加入CA或EDTA可有效改善活性组分在载体上的分散状态,减弱活性组分与载体间的相互作用;加入CA可明显改进催化剂的选择性加氢脱硫性能;而加入EDTA同时提高了催化剂的脱硫活性和加氢活性,没能改善催化剂的选择性加氢脱硫性能。     

The Role of Nitrogen in Facilitating Methylcyclohexane Aromatization on Pt/Al2O3 and Pt-Re/Al2O3 Catalysts

Abstract

The kinetics of methylcyclohexane aromatization on commercial Pt/Al₂O₃ and Pt-Re/Al₂O₃ catalysts was investigated in a micro-reactor using N₂ and/or H₂ as carrier gases at temperatures ranging between 300–500°C, W/F values ranging between 0.83–3.75 mg min/mL and at a total pressure of 4.0 kg/cm². On both catalysts in N₂ atmosphere, aromatization accompanied by demethylation was observed with the formation of cracked products, benzene and toluene. However, in H₂ methane was the predominant product of methylcyclohexane reforming on PtA1₂O₃ and Pt-Re/Al₂O₃ at 500°C and 400–500°C respectively, whereas at 350°C, aromatization was predominant on Pt/Al₂O₃ but on Pt-Re/Al₂O₃, aromatization was accompanied by fragmentation to methane. In N₂–H₂ mixtures, demethylation activity was observed to decrease with H₂ content of the mixture on Pt-Re/Al₂O₃. A preliminary test of the kinetic data using Sica's method of pulse kinetic analysis suggests a first order rate in methylcyclohexane with activation energies of 3.21 kcal/gmol in N₂ and 19.70 kcal/gmol in H₂ for the Pt/Al₂O₃ catalyst and 16.66 kcal/gmol in N₂ and 34.94 kcal/gmol in H₂ for the Pt-Re/Al₂O₃ catalyst. However, a more comprehensive kinetic analysis suggested an aromatization mechanism for Pt-Re/Al₂O₃, where adsorbed H₂ was a participant. A different aromatization mechanism for the reaction in N₂ where hydrogen was not needed explained the data on Pt/Al₂O_3. In both cases, the desorption of toluene was determined as the rate determining step.     

预处理方法对Mo-Ni/γ-Al2O3催化剂加氢脱氧性能的影响

采用浸渍法制备了Mo-Ni/γ-Al2O3催化剂,利用BET、XRD、NH3-TPD等方法对还原态和硫化态Mo-Ni/γ-Al2O3催化剂进行了表征,并以模型化合物乙酸和F-T合成轻质油为原料,研究了还原态和硫化态催化剂的加氢脱氧(HDO)性能。结果表明,还原态催化剂具有较大的比表面积和孔体积,活性组分分散度较高;硫化态催化剂的酸性大于还原态催化剂。还原态催化剂具有比硫化态催化剂更好的HDO催化活性,不论是对模型化合物乙酸还是F-T合成轻质油都能获得更高的转化率;但用模型化合物乙酸的研究结果表明,硫化态催化剂不利于C—C键的断裂。