噻吩加氢脱硫和四氢萘催化加氢反应中的载体和助剂的影响

 为了更好地认识加氢脱硫和催化加氢反应中的载体影响和助剂效应，在同样的催化剂制备方法及反应条件下，研究了噻吩加氢脱硫（HDS）和四氢萘催化加氢（HYD）反应．结果表明，对于无助剂的Mo和W催化剂，载体对催化活性的影响顺序为TiO2－Al2O3＞ZrO2＞Al2O3．助剂的添加改变了催化剂活性顺序．Ni助剂催化剂的活性明显高于Co助剂催化剂．ZrO2担载的添加Ni的Mo和W催化剂分别获得了最佳的HDS和HYD活性．然而，添加Pt的Mo和W催化剂其HDS和HYD活性仅是Pt与Mo（W）二者的加和，Pt与Mo（W）之间没有协同效应．先将担载的Mo和W预硫化再将助剂引入体系的催化剂制备方法可以避免Ni和Co过早硫化形成类硫化镍（或硫化钴）物相，与采用螯合物分子方法制备的催化剂间有一定的相似性．     

Mo（W）－Co（Ni，Fe）簇合物的加氢脱硫催化活性

对线型、立方烷型和笼状３种不同构型的Ｍｏ（Ｗ）－Ｃｏ（Ｎｉ，Ｆｅ）－Ｓ（Ｏ）簇共１２种化合物进行了噻吩加氢脱硫和环己烯加氢的催化活性研究．讨论了簇合物的组成，金属原子的配比、价态与催化活性的关系．探讨了不同构型对活性的影响．     

CO吸附原位红外光谱结合分子模拟计算研究FCC汽油加氢脱硫催化剂的选择性

以脱硫选择性不同的2组催化裂化汽油加氢脱硫催化剂为研究对象, 采用CO吸附原位红外光谱表征了2组催化剂的活性相特征, 并通过分子模拟计算方法比较了助剂Co加入前后噻吩和1-己烯在催化剂表面的电荷分布、吸附能及其加氢反应的活化能等, 探讨了助剂Co的加入对选择性加氢脱硫催化剂脱硫选择性的作用机理. 结果表明, 加氢脱硫催化剂CoMoS活性相的增加有利于提高催化剂的加氢脱硫/加氢降烯烃(HDS/HYD)选择性. 与1-己烯加氢位相比, Co的加入显著提高了噻吩分子加氢位的缺电子性, 噻吩在催化剂表面的吸附度增强, 显著降低噻吩加氢反应的能垒, 从而使噻吩加氢反应更易进行. 这也表明CoMoS为高HDS活性、高HDS/HYD选择性的活性相.     

镍钼杂多酸制备NiMo/γ-Al2O3催化剂及硼、钴或镍改性氧化铝的影响（英文）

A hydrotreating NiMo/γ-Al2O3 catalyst(12 wt% Mo and 1.1 wt% Ni) was prepared by impregnation of the support with the Anderson-type heteropolyoxomolybdate(NH4)4Ni(OH)6Mo6O18.Before impregnation of the support,it was modified with an aqueous solution of H3BO3,Co(NO3)2,or Ni(NO3)2.The catalysts were investigated using N2 adsorption,O2 chemisorption,X-ray diffraction,UV-Vis spectroscopy,Fourier transform infrared spectroscopy,temperature-programmed reduction,temperature-programmed desorption,and X-ray photoelectron spectroscopy.The addition of Co,Ni,or B influenced the Al2O3 phase composition and gave increased catalytic activity for 1-benzothiophene hydrodesulfurization(HDS).X-ray photoelectron spectroscopy confirmed that the prior loading of Ni,Co or B increased the degree of sulfidation of the NiMo/γ-Al2O3 catalysts.The highest HDS activity was observed with the NiMo/γ-Al2O3 catalyst with prior loaded Ni.     

Ni2P加氢脱硫催化剂

环境法规对硫氧化物脱出的限制日益严格以及原油品质的不断下降,使得有必要研发高效的加氢脱硫催化剂。Ni2P由于具有优异的加氢脱硫活性和稳定性,引起了广泛的关注。本文综述了Ni2P加氢脱硫催化剂的特性、反应活性相、制备方法、改进和加氢脱硫活性等方面的研究进展。在Ni2P中存在两种不同的初始活性位,四面体几何构型的Ni(1)初始活性位在加氢脱硫反应中参与直接脱硫反应,四方锥几何构型的Ni(2)初始活性位则与催化剂的高加氢活性有关。在加氢脱硫反应中,催化剂表面生成的NixSyP相被认为是真正的活性相。制备Ni2P的方法主要是程序升温还原和液相合成。载体、助剂和络合剂对Ni2P活性相的形成和催化剂的活性有重要影响。相比于商用硫化物催化剂,Ni2P催化剂对噻吩、二苯并噻吩和4,6-二甲基二苯并噻吩均表现出更高的加氢脱硫活性。     

Co调变MoS2催化剂的作用本质及其FCC汽油选择性加氢脱硫机理

采用含硫前驱体四硫代钼酸铵直接构建MoS₂催化剂,通过调变Co/Mo原子比深入认识Co调变MoS₂催化剂的作用本质及其FCC汽油选择性加氢脱硫机理。借助XRD、HRTEM、XPS、H₂-TPR和Py-FTIR表征发现,Co/Mo原子比能够影响催化剂的活性相微观结构组成,从而影响催化剂的加氢脱硫活性和选择性。当Co/Mo（atomic ratio）<0.2时,助剂Co原子倾向于占据MoS₂相的边角位而形成CoMoS活性相,明显提高了催化剂的加氢脱硫活性;当0.2 < Co/Mo（atomic ratio） < 0.6时,助剂Co在催化剂表面形成适量的Co₉S₈相,其产生的溢流氢能提高硫化物的脱除活性而对烯烃饱和活性的影响较小;当Co/Mo（atomic ratio）>0.6时,过量的Co会形成大颗粒的Co₉S₈相,阻碍硫化物和烯烃与催化剂活性中心的接触,从而降低催化剂的活性和选择性。     

β-Mo2N0.78/γ-Al2O3催化剂的制备及其噻吩加氢脱硫活性的研究

以γ-Al2O3为载体，钼酸铵为氧化钼前驱体，采用在N2-H2气氛下的程序升温还原氮化反应，制备β-Mo2N0.78/γ-Al2O3催化剂，以噻吩为模型化合物，考察了该催化剂的加氢脱硫反应性能，以及反应温度、氢还原预处理和钴、镍助剂的引入等因素对催化剂活性的影响。结果表明，在320 ℃～400 ℃之间，随着反应温度的升高，催化剂的活性逐渐增加；预还原则降低了催化剂的活性；添加钴、镍均在一定负载量范围内可以改善β-Mo2N0.78/γ-Al2O3催化剂的加氢脱硫活性，但镍对催化剂活性的影响要小于钴。     

Comparing the hydrodesulfurization reaction of thiophene on γ-Al2O3 supported CoMo, NiMo and NiW sulfide catalysts

The thiophene hydrodesulfurization (HDS) reaction on γ-Al₂O₃ supported CoMo, NiMo and NiW sulfide catalysts was compared in order to gain insight into the promoter effect on direct desulfurization (DDS) and hydrogenation (HYD) pathways. Ni-promoted Mo (or W) sulfide catalysts favor the hydrogen transfer reactions relative to CoMo sulfide catalyst, which facilitates the direct route instead. This different performance and also the dependence of the apparent Arrhenius parameters with the catalyst formulation were attributed to the major participation of Mo (or W) edge for the Ni-containing catalysts and S edge for CoMo sulfide catalyst upon the thiophene-HDS reaction.     

Kinetics of thiophene hydrodesulfurization over a supported Mo–Co–Ni catalyst

In this study, the kinetics of thiophene (TH) hydrodesulfurization (HDS) over the Mo–Co–Ni-supported catalyst was investigated. Trimetallic catalyst was synthesized by pore volume impregnation and the metal loadings were 11.5 wt % Mo, 2 wt % Co, and 2 wt % Ni. A large surface area of 243 m²/g and a relatively large pore volume of 0.34 cm³/g for the fresh Mo–Co–Ni-supported catalyst indicate a good accessibility to the catalytic centers for the HDS reaction. The acid strength distribution of the fresh and spent catalysts, as well as for the support, was determined by thermal desorption of diethylamine (DEA) with increase in temperature from 20 to 600 °C. The weak acid centers are obtained within a temperature range between 160 and 300 °C, followed by medium acid sites up to 440 °C. The strong acid centers are revealed above 440 °C. We found a higher content of weak acid centers for fresh and spent catalysts as well as alumina as compared to medium and strong acid sites. The catalyst stability in terms of conversion as a function of time on stream in a fixed bed flow reactor was examined and almost no loss in the catalyst activity was observed. Consequently, this fact demonstrated superior activity of the Mo–Co–Ni-based catalyst for TH HDS. The activity tests by varying the temperature from 200 to 275 °C and pressure from 30 to 60 bar with various space velocities of 1–4 h^?1 were investigated. A Langmuir–Hinshelwood model was used to analyze the kinetic data and to derive activation energy and adsorption parameters for TH HDS. The effect of temperature, pressure, and liquid hourly space velocity on the TH HDS activity was studied.     

Elucidation of hydrodesulfurization mechanism on molybdenum‐based catalysts using 35S radioisotope pulse tracer methods

Elucidation of the hydrodesulfurization (HDS) mechanism on molybdenum‐based catalysts using radioisotope tracer methods and reaction kinetics is reviewed. Firstly, to investigate the sulfidation state in Mo/Al₂O₃ and Co–Mo/Al₂O₃ catalysts, presulfiding of these catalysts has been performed using a ³⁵S pulse tracer method. Secondly, HDS of radioactive ³⁵S‐labeled dibenzothiophene was carried out over a series of sulfided molybdena–alumina catalysts and cobalt‐promoted molybdena–alumina catalysts in a pressurized flow reactor to estimate the behavior of sulfur on the working catalysts. Finally, sulfur exchange of a ³⁵S‐labeled catalyst with hydrogen sulfide was performed to estimate the relationship between the amount of labile sulfur and catalytically active sites.     

助剂Ni与载体的相互作用及其对NiMo/γ-Al_2O_3催化剂加氢脱硫性能的影响

以γ-Al_2O_3为载体,制备了一系列不同NiO负载量的NiMo/γ-Al_2O_3催化剂,利用XRD、~(27)Al-MAS NMR、Py-FTIR和HRTEM等技术对其进行了表征;在高压微反装置对该系列催化剂的加氢脱硫性能进行了评价,研究了助剂Ni与载体γ-Al_2O_3中不饱和铝间的相互作用及其对催化剂活性相结构形貌和催化活性的影响。结果表明,助剂Ni优先作用于γ-Al_2O_3表面的四配位不饱和铝原子位置;随着NiO负载量的增加,硫化态NiMo/γ-Al_2O_3催化剂中MoS_2活性相的长度变短、堆垛层数增加。Ni的引入能明显提高NiMo/γ-Al_2O_3催化剂的加氢脱硫活性,但其加氢选择性则有所降低。     

准“原位”XPS技术研究加氢精制催化剂的硫化过程

用准“原位”XPS技术研究了Mo/Al_2O_3、Mo/TiO_2-Al_2O_3、CO/Al_2O_3、CO/TiO_2-Al_2O_3、Co-Mo-Al_2O_3和Co-Mo/TiO_2-Al_2O_3等催化剂的硫化过程．结果表明：对以Al_2O_3为载体的催化剂，当Mo或Co载量较低(分别低于0.05 gMoO_3/gAl_2O_3或0.03gCoO/gAl_2O_3)时，没有Mo或Co硫化物的生成，而以TiO_2改性的Al_2O_3为载体的催化剂，Mo/TiO_2-Al_2O_3催化剂的硫化较Mo/Al_2O_3容易得多, 表现为在较低温度下，负载在TiO_2改性Al_2O_3载体上的MoO_3，能很快硫化并达到相当大的硫化度, 对Co/Al_2O_3催化剂而言，即使在较高温度400 ℃时，载体上高分散的CoO物种仍难以硫化；而Co_3O_4微晶的硫化却容易得多, 载体用TiO_2改性，并不影响高分散形态的CoO催化剂的硫化，却明显地影响Co_3O_4微晶的硫化．噻吩加氢脱硫(HDS)的活性测量指出，对Co-Mo/Al_2O_3和Co-Mo/TiO_2-Al_2O_3催化剂而言，HDS活性和硫化度之间存在着良好的相关性．并用TiO_2改性载体，可以增加Co-Mo催化剂的HDS活性和硫化度.     

Mo-Ni-γ-Al2O3体系中Mo、Ni近邻结构的EXAFS研究

运用EXAFS技术对加入P2O5或TiO2的MO-Ni-γ-Al2O3体系中Mo、Ni的K吸收边进行了分析，获得了体系中金属组分原子周围的微观结构信息，从而进一步证实P或Ti的加入有助于含量较高的Mo、Ni在载体表面的高度分散，样品中适量的P有助于形成较多的八面体结构，所有含P的样品中八面体结构含量均高于含Ti的样品，八面体结构Mo-O键上的氧在加氢脱硫反应中较易被硫取代，因而提高反应活性，这是含八面体结构较多的MoNiP样品的加氢脱硫活性优于MoNiTi样品的一个重要原因.     

On the relationship between the preparation method and the physicochemical and catalytic properties of the CoMo/gamma-Al(2)O(3) hydrodesulfurization catalysts

A series of CoMo/gamma-Al(2)O(3) catalysts have been prepared using various methodologies. One of them (EDF) was prepared by depositing the Mo species on the support via the equilibrium deposition filtration (EDF) technique and then the Co species by dry impregnation. Another catalyst (co-EDF) was prepared by depositing the Co and Mo species simultaneously via EDF. A third catalyst (co-WET) was prepared by depositing Mo and Co species simultaneously using the wet impregnation method. The fourth catalyst (WET) was prepared by depositing the Mo species through wet impregnation and then the Co species by dry impregnation. Finally, the fifth catalyst (s-DRY) was prepared by mounting the Mo species through successive dry impregnations and then the Co species by dry impregnation. In all cases the Mo and Co content was identical, giving a Co/(Co+Mo) ratio equal to 0.13. These catalysts were characterized using various physicochemical techniques (BET, NO chemisorption, DRS, LRS, TPR, and XPS), and their catalytic activity for the hydrodesulfurization of thiophene was determined. The trend observed for the HDS activity (namely, EDF>co-EDF>co-WET>s-DRY>WET) is attributed to similar trends observed for both the fraction of well-dispersed octahedral cobalt in the oxidic precursors and the concentration of the edge sulfur vacancies formed on the active phase of the sulfided samples. The EDF and co-EDF catalysts exhibited relatively low hydrogenating activity. The maximum HDS activity, achieved over the EDF catalyst, suggested the most suitable preparative strategy for the preparation of very active and less hydrogen-demanding CoMo/gamma-Al(2)O(3) HDS catalysts.     

Highly active CoMo HDS catalyst for the production of clean diesel fuels

HY–Al₂O₃-supported CoMo catalysts with a chelating agent and phosphorus for the hydrodesulfurization (HDS) of diesel fractions were prepared. The activity measurements with the prepared catalysts were carried out with straight-run light gas oil feedstocks in a pilot plant under industrial hydrotreating conditions. As a result, Cosmo Oil Co., Ltd. developed a new CoMoP/HY–Al₂O₃ catalyst, C-606A, which had three times higher HDS activity than the conventional CoMoP/Al₂O₃ catalyst. Commercial operations to produce ultra-low sulfur diesel (ULSD) with C-606A have successfully demonstrated its high performance and high stability. This catalyst has an extremely high activity, which enables to achieve <10-ppm sulfur in products in diesel hydrotreater designed to produce 500-ppm sulfur diesel fuels. Mo K-edge EXAFS, TEM and FT-IR of adsorbed NO were performed to investigate the nature of the active sites on the developed catalysts. The results showed that the new catalyst has multiple layers of MoS₂ slabs and the edges of MoS₂ are mainly occupied by Co–Mo–S phases. XPS and FT-IR were used to investigate the sulfiding behavior of Co and Mo in the formation process of the active sites during sulfidation. The results showed that addition of carboxylic acid to the impregnation solution postponed the sulfidation of Co at low temperatures, thereby increasing formation of the Co–Mo–S phase.     

Synthesis of Ni2P promoted trimetallic NiMoW/γ-Al2O3 catalysts for diesel oil hydrotreatment

The Ni2P promoted and γ-Al2O3 supported NiMoW sulfide catalyst consisting of 4 wt% Mo, 22 wt% W, 2 wt% Ni and 2.5 wt% Ni2P was synthesized by a co-impregnation method. The catalysts were characterized by N2 adsorption-desorption, X-ray diffraction (XRD), diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, NH3 temperature-programmed desorption (NH3-TPD) and transmission electron microscopy (TEM). The results showed that Ni2P, Ni, Mo and W species were highly dispersed over γ-Al2O3. The hydrodesulfurization (HDS) of dibenzothiophene (DBT) showed that the presence of Ni2P brought a strong promotional effect on the HDS activity, which was further confirmed by the HDS and hydrodenitrogenation (HDN) of diesel oil under industrial conditions. The enhancement in HDN activity and stability by Ni2P addition could be attributed more to the effect of new active sites of Ni2P than that of acidity modification. The as-prepared Ni2P-NiMoW/γ-Al2O3 catalyst showed better hydrotreating performance than NiMoW/γ-Al2O3 and commercial catalysts.     

Sulfur‐33 Isotope Tracing of the Hydrodesulfurization Process: Insights into the Reaction Mechanism,Catalyst Characterization and Improvement

The novel approach based on ³³S isotope tracing is proposed for the elucidation of hydrodesulfurization (HDS) mechanisms and characterization of molybdenum sulfide catalysts. The technique involves sulfidation of the catalyst with ³³S‐isotope‐labeled dihydrogen sulfide, followed by monitoring the fate of the ³³S isotope in the course of the hydrodesulfurization reaction by online mass spectrometry and characterization of the catalyst after the reaction by temperature‐programmed oxidation with mass spectrometry (TPO‐MS). The results point to different pathways of thiophene transformation over Co or Ni‐promoted and unpromoted molybdenum sulfide catalysts, provide information on the role of promoter and give a key for the design of new efficient HDS catalysts.     

Sulfur‐33 Isotope Tracing of the Hydrodesulfurization Process: Insights into the Reaction Mechanism,Catalyst Characterization and Improvement

The novel approach based on ³³S isotope tracing is proposed for the elucidation of hydrodesulfurization (HDS) mechanisms and characterization of molybdenum sulfide catalysts. The technique involves sulfidation of the catalyst with ³³S‐isotope‐labeled dihydrogen sulfide, followed by monitoring the fate of the ³³S isotope in the course of the hydrodesulfurization reaction by online mass spectrometry and characterization of the catalyst after the reaction by temperature‐programmed oxidation with mass spectrometry (TPO‐MS). The results point to different pathways of thiophene transformation over Co or Ni‐promoted and unpromoted molybdenum sulfide catalysts, provide information on the role of promoter and give a key for the design of new efficient HDS catalysts.     

钴掺杂对碳化钼催化噻吩加氢脱硫性能的影响

以MoO3和CoMo混合氧化物为前驱体, 制备了碳化钼和碳化钼-钴催化剂, 采用XRD, BET, SEM和XPS等技术对其进行了表征, 研究了Co掺杂对碳化钼催化剂噻吩加氢脱硫性能的影响. 结果表明, 掺入适量的Co后制得的CoMo双金属混合氧化物为MoO3和CoMoO4的两相混合体, 经CH4/H2气氛程序升温还原碳化反应生成共生共存的Co-Mo2C, Co以金属细颗粒的形态均匀地分散在生成的Mo2C组分之间. 在共生过程中含Co物种的掺入可降低制备碳化钼所需要的还原碳化温度, 使制备的碳化钼颗粒变小, 比表面积增大, 表面Mo2+含量增多, 从而对碳化钼的噻吩加氢脱硫活性有较好的促进作用, Co的添加量以Co/Mo摩尔比为0.2左右较为适宜. 用化学共沉淀法制得的Co-Mo2C共生共存体系的噻吩加氢脱硫反应活性, 好于由金属Co与Mo2C机械混合法制得的Co+Mo2C二相共存体系. 这表明当两个活性相共存时, 只有经过相互共生过程才能发挥其最佳的协同效应.     

柴油馏分加氢脱硫动力学及反应器研究进展

当前各国环保法规对柴油中硫的质量分数的限制越来越严格。催化加氢脱硫是实现柴油低硫化的重要途径,动力学和新反应器的研究受到了研究者的广泛关注。本文介绍了柴油馏分中两种典型的难脱除含硫化合物二苯并噻吩和4,6-二甲基二苯并噻吩在各类催化剂上加氢脱硫的反应路径,比较了这两种模型含硫化合物的直接脱硫（DDS）和先加氢再脱硫（HYD）路径相对快慢的影响因素。详细综述了假1级、假2级、快慢1级、n级、L-H以及抑制剂H2S存在下的动力学模型在描述二苯并噻吩类模型化合物及真实油品的加氢脱硫过程中的研究现状,介绍了神经网络在柴油加氢动力学和脱硫率预测方面的研究进展。还对催化精馏、并流-逆流滴流床、两相床反应器等新型加氢脱硫反应器的最新发展作了综述,展望了加氢脱硫动力学及反应器的研究方向和面临的挑战。