加氢催化剂预硫化的影响因素

加氢催化剂的预硫化是提高催化剂活性、优化加氧催化操作,获得理想经济效益的关键技术之一。为获得理想的预硫化效果,必须严格控制各阶段的反应条件。介绍了加氢催化剂预硫化的反应原理,探讨了在预硫化过程中影响催化剂预硫化效果的因素。预硫化操作中,温度是最敏感的因素之一。     

加氢催化剂预硫化的影响因素

加氢催化剂的预硫化是提高催化剂活性，优化加氢催化操作，获得理想经济效益的关键技术之一。为获得理想的预硫化效果，必须严格控制各阶段的反应条件。文章介绍了加氢催化剂预硫化的反应原理，探讨了在预硫化过程中影响催化剂预硫化效果的因素。预硫化操作中，温度是最敏感的因素之一。     

加氢催化剂的器外预硫化技术研究

加氢催化剂硫化的预处理过程是决定催化剂活性和选择性的重要环节。采用气相硫化技术在小型固定床流化反应器上对加氢催化剂进行器外预硫化的研究，通过N₂吸附、TEM、TG-DTA、XRD和H₂-TPR等技术对处理后的催化剂进行表征。结果表明,不同的硫化方法对催化剂中硫的质量分数和活性均有很大影响。预硫化后的催化剂中硫的质量分数高，活性好。     

加氢催化剂预硫化技术探讨

1前言加氢催化剂大多采用Mo、Co、Ni、W等金属元素作组分，并以氧化态分散在多孔的载体上。大量的研究试验结果表明，这种形态的催化剂加氢活性低，活性稳定性差。若将催化剂经过预硫化处理，即在硫化剂和氢气存在下使氧化态金属转化为硫化态金属，则硫化态催化剂的活性和稳定性均高于氧化态催化剂。催化剂预硫化技术是加氢催化剂开发应用的关键步骤之一。当今，随着催化剂制备技术的发展，促进了国内外对加氢催化剂预硫化技术的基础研究和应用研究。最佳的预硫化技术能够使加氢催化剂保持最佳的加氢活性和活性稳定性，提高催化剂的选择性…     

器外预硫化催化剂加氢脱酸性能研究

为探索器内硫化与器外预硫化催化剂的催化活性,采用等体积浸渍法制备同一批次镍-钨氧化态催化剂,分别采用器内硫化与器外预硫化得到3种不同的催化剂,考察3种新鲜催化剂的物化性质、催化活性和使用后催化剂的物化性质。结果表明：随着催化剂上硫化物负载量增加,预硫化催化剂的表观密度增加,比表面积、孔容、平均孔径均降低,同时预硫化催化剂在各个孔径范围内的分布均降低;3种催化剂中高负载硫的器外预硫化催化剂上W ⁴⁺态金属和NiWS活性相原子分数最高,器内硫化催化剂次之,低负载硫的器外预硫化催化剂最低;在反应压力为3.0 MPa、空速为1.0 h ^-1、氢油体积比为400∶1条件下,以绥中常二线、减三线馏分油为原料在不同反应温度下评价催化剂的活性,高负载硫的器外预硫化催化剂的脱酸、脱硫、脱氮活性最高,器内硫化催化剂次之,低负载硫的器外预硫化催化剂的催化活性最差。     

加氢催化剂预硫化技术现状

介绍了器内预硫化和器外预硫化两种加氢催化剂预硫化技术,阐述了催化剂预硫化反应原理,并对硫化剂进行了比选,讨论了干法硫化和湿法硫化两种器内预硫化技术的特点。干法硫化技术主要适用于分子筛含量较高的加氢催化剂,而湿法硫化技术主要适用于加氢精制类催化剂。通过对比器内预硫化与器外预硫化技术的优缺点,并对国内外器外预硫化技术研究现状进行了综述,认为器外预硫化技术具有开工时间短、环境污染小等优点,必将逐渐替代现有的器内预硫化技术成为加氢催化剂预硫化的主要技术,将是加氢催化剂预硫化技术未来研究发展的方向。     

加氢催化剂预硫化技术分析

主要就加氢催化剂预硫化技术进行深入的探究,分析催化剂预硫化反应的原理,同时还需要开展一系列的硫化剂比对选择工作,总结各类预硫化技术的使用特点。其中干法硫化技术主要应用到分子筛含量比较高的加氢催化剂中,湿法硫化技术主要应用到加氢精制类的催化剂。对器内预硫化与器外预硫化技术进行了比较,分析了二者技术的优缺点,同时还论述了国内外器外预硫化技术的使用现状。器外预硫化技术的实际开工时间都比较短,且其给环境所造成的污染程度微弱,可以将其取代原本的器内预硫化技术,让其成为未来我国加氢催化剂预硫化技术的发展方向。     

浅析加氢催化剂预硫化技术研究进展

预硫化是加氢催化剂必不可少的活化步骤。综述了加氢催化剂预硫化技术的发展、反应原理,介绍了几种新型加氢催化剂预硫化技术及应用,提出了器外预硫化是预硫化技术的发展方向。     

苯加氢催化剂预硫化技术探讨

催化剂预硫化可以提高催化剂活性和稳定性,延长催化剂使用寿命。介绍了苯加氢催化剂预硫化的反应原理、目前工业应用的硫化技术及影响硫化的因素。对不同的催化剂硫化方法进行了比较,针对影响硫化的因素,提出了操作时的注意事项。     

加氢催化剂器外预硫化技术

简述了器外预硫化技术的优点,介绍了加氢催化剂器外预硫化技术的发展历程,并以浙江某化学公司采用的抚研院开发的FRIPP EPRES器外预硫化型催化剂一次开车成功的工业应用说明,器外预硫化技术可以消除开工过程中硫化剂对人体健康、安全的危害以及对环境的污染,减少装置污油排放,简化炼油装置的开工过程,大大降低开工成本。此项新技术具有良好的推广前景。     

一种体相加氢脱硫催化剂的程序升温硫化表征

在全自动化学吸附仪上,用程序升温硫化（TPS）技术对一种体相加氢脱硫催化剂进行表征,考察了金属与载体的相互作用、金属间的相互作用以及焙烧温度对这种催化剂硫化性能的影响。结果表明,MoO3负载于Al2O3载体后,硫化峰温大幅降低,并在TPS谱图中体现出分步硫化的过程,证明MoO3与载体间存在相互作用,形成了易于硫化还原的活性中心。当Mo和Ni共同作用于载体时,形成了更易于硫化的Mo-Ni-O复合相。Co的加入加强了Mo与Ni间的协同作用,Co、Mo、Ni与Al形成了更易硫化的活性中心。W的加入反而改变了硫化中心的性质,使硫化温度提高。对（Mo＋Ni）/Al2O3和（Co＋Mo＋Ni）/Al2O3催化剂,于500℃焙烧时,催化剂硫化性能最好。最后得出结论：当Co、Mo、Ni 3种金属共同作用于载体,并于500℃焙烧时,其硫化中心活性最高。     

MoS2基催化剂加氢脱硫反应活性相和作用机理研究进展

加氢脱硫工艺在清洁油品生产过程中发挥着重要作用，而MoS₂基催化剂是加氢脱硫的主要催化剂，因此对MoS₂基催化剂活性相和催化反应机理的深入研究有助于从原子层面上对催化剂进行优化设计。本文首先介绍了国内外有关MoS₂基催化剂活性相形貌结构的研究，着重探讨了硫化气氛、助剂和载体类型对活性相结构的影响，以及现有表征技术在MoS₂基催化剂活性相形貌结构研究中所面临的挑战，总结了不同条件下活性相的微观结构特征；同时，从MoS₂基催化剂的活性相组成和结构角度分析了噻吩的加氢脱硫机理，发现了加氢脱硫活性与催化剂微观结构之间的紧密联系；最后展望了理论计算在设计和开发高效加氢脱硫催化剂过程中的重要指导作用。     

Catalytic activities of Co(Ni)Mo/TiO2–Al2O3 catalysts in gasoil and thiophene HDS and pyridine HDN: effect of the TiO2–Al2O3 composition

The effect of the TiO₂–Al₂O₃ mixed oxide support composition on the hydrodesulfurization (HDS) of gasoil and the simultaneous HDS and hydrodenitrogenation (HDN) of gasoil+pyridine was studied over two series of CoMo and NiMo catalysts. The intrinsic activities for gasoil HDS and pyridine HDN were significantly increased by increasing the amount of TiO₂ into the support, and particularly over rich- and pure-TiO₂-based catalysts. It is suggested that the increase in activity be due to an improvement in reducing and sulfiding of molybdena over TiO₂. The inhibiting effect of pyridine on gasoil HDS was found to be similar for all the catalysts, i.e., was independent of the support composition. The ranking of the catalysts for the gasoil HDS test differed from that obtained for the thiophene test at different hydrogen pressures. In the case of gasoil HDS, the activity increases with TiO₂ content and large differences are observed between the catalysts supported on pure Al₂O₃ and pure TiO₂. In contrast, in the case of the thiophene test, the pure Al₂O₃-based catalyst appeared relatively more active than the catalysts supported on mixed oxides. Also, in the thiophene test the difference in intrinsic activity between the pure Al₂O₃-based catalyst appeared relatively more active than the catalysts supported on mixed oxides. Also in the thiophene test, the difference in intrinsic activity between the pure Al₂O₃- and pure TiO₂-based catalysts is relatively small and dependent on the H₂ pressure used. Such differences in activity trend among the gasoil and the thiophene tests are due to a different sensitivity of the catalysts (by different support or promoter) to the experimental conditions used. The results of the effect of the H₂ partial pressure on the thiophene HDS, and on the effect of H₂S concentration on gasoil HDS demonstrate the importance of these parameters, in addition to the nature of the reactant, to perform an adequate catalyst ranking.     

Co-Mo系耐硫变换催化剂硫化行为的研究

本文采用程序升温硫化(TPS)技术,对未负载的Co?Mo氧化物和负载在不同载体上的Co和/或Mo系催化剂的硫化过程进行了研究,分析了活性组分Co?Mo在催化剂硫化过程中的形态变化和催化剂的硫化机理,同时还探讨了载体在催化剂硫化过程中的作用。     

Effect of the activation process on thiophene hydrodesulfurization activity of activated carbon-supported bimetallic carbides

The effect of passivation and presulfidation after carbiding of activated carbon-supported Fe–Mo, Co–Mo and Ni–Mo catalysts on their thiophene HDS activity was evaluated. Catalytic precursors were prepared by co-impregnation of the support with solutions of ammonium heptamolybdate and the promotor nitrates or sulfates. Carbiding was achieved by means of the carbothermal method, employing pure H₂ as reductant and the support as the carbon source. Carbided samples were submitted to one out of three types of procedures before HDS tests: (a) passivation at room temperature followed by presulfiding; (b) presulfiding (no passivation); and (c) neither passivation nor sulfiding before HDS. Samples of passivated catalysts prepared from the sulfates of Fe, Co or Ni contained variable amounts of sulfur, as shown by XPS and elemental analysis, while XRD showed only metals and mixed Fe₃Mo₃C or η-M₆Mo₆C₂ (MCo, or Ni) phases. The nitrate-derived catalysts only presented β-Mo₂C and metals (XRD). Sulfur containing catalysts showed high initial activities although deactivate strongly during the first 40 min on the reaction stream, while the unsulfided nitrate-derived samples showed a more stable behavior and lower activities during the 2–3 h of testing. In general, samples submitted to passivation followed by presulfiding showed the higher steady state activities and those neither passivated nor sulfided were the less active. The results show the benefits of a passivating treatment on these carbon-supported catalysts, and point out to the importance of sulfided surface phases in HDS on carbides of transition metal catalysts.     

Co—Mo系耐硫变换催化剂的TPS表征研究

使用程度升温硫化（ＴＰＳ）实验手段研究了一系列Ｃｏ、Ｍｏ和Ｃｏ－Ｍｏ耐硫变换催化剂。结果表明：Ｃｏ３Ｏ４和ＭｏＯ３的硫化还原温度较高;而负载在载体上的活性组分Ｃｏ、Ｍｏ的硫化还的温度大大降低,而且催化剂的硫化还原反应是多步进行的,受Ｏ－Ｓ交换反应控制。     

SBA-15-supported nickel phosphide hydrotreating catalysts

A series of Ni₂P and Ni₁₂P₅ hydrotreating catalysts supported on SBA-15 ordered mesoporous silica were prepared by impregnation of nickel phosphate precursors followed by reduction in hydrogen at 873 K. The major product was Ni₂P with additional phosphate species when a high excess of phosphorus was used (P/Ni = 2). When a stoichiometric amount of P was used (P/Ni = 0.5), the sole product was Ni₁₂P₅ without Ni₂P and phosphate byproducts. The active site density as determined by CO chemisorption for such Ni₁₂P₅ phases was about three times higher than typically found for Ni₂P/SiO₂ catalysts and in good accord with active site densities following from particle size. The excess phosphorus results in mesopore blocking by unreduced phosphate species, impeding the accessibility of the Ni₂P active sites as probed by CO chemisorption. The catalysts exhibited lower hydrodesulfurization (HDS) but similar or somewhat higher hydrodenitrogenation (HDN) activities than reference alumina-supported NiMo or CoMo catalysts in simultaneous thiophene HDS and pyridine HDN, as well as parallel dibenzothiophene HDS and ortho-methyl aniline HDN hydrotreating reactions. In general, the intrinsic activities of the Ni₂P catalysts were higher than those of Ni₁₂P₅ catalysts. The activities of these phosphide catalysts were found to be stable or increasing with reaction time. X-ray photoelectron studies of reduced catalysts exposed to a sulfiding mixture suggest that this increase is due to in situ sulfidation of the nickel phosphide to nickel phosphosulfide. Thus, it seems reasonable that surface phosphosulfides form the active catalytic surface in these catalysts.     

载体性质对耐硫变换催化剂硫化性能的影响

利用程序升温硫化（TPS）技术考察了四种不同类型载体的耐硫变换催化剂的硫化性能，结果发现,载体性质是影响催化剂硫化性能的重要因素，在载体中添加特种助剂，能显著提高催化剂的易硫化性能，降低硫化温度。     

Effect of sulfidation process on catalytic performance over unsupported Ni-Mo-W hydrotreating catalysts

Oxidic unsupported Ni-Mo-W catalysts were chosen to elucidate the effect of sulfidation conditions on the catalytic performance. The catalysts were sulfided in situ by using dimethyl sulfide as sulfiding agent. The relationships between the time needed for sulfidation and the sulfiding conditions were studied by GC-analysis method. Straight-run gas oil with high sulfur and nitrogen content was used to evaluate the hydrotreating performance. The oxidic catalyst precursors and sulfided catalysts were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS). With increasing sulfiding liquid hourly space velocity (LHSV) of the sulfiding agent, the reaction time necessary for the sulfidation decreased, while the activity of the catalyst increased significantly. The higher catalytic activity might be due to the MoS₂/WS₂ slabs with shorter length and higher stacking number, which might contribute to the catalyst with more active sites. Sulfiding at 330 °C took the longest sulfidation time, while the catalytic activity was also the highest after sulfiding at this temperature. Furthermore, within a certain range, the sulfidation pressure had no evident effect on the catalytic behavior or activity. The purpose of this work was to provide a basis for actual production and a reference for further research.     

环烷基润滑油加氢催化剂补硫过程分析及优化

针对环烷基油高氮、低硫的特点,通过对硫化钨和硫化镍在氢气中相平衡态所需硫化氢浓度的理论分析,对反应器入口所需补硫量作了详细的阐述,得出了最经济的补充注硫量。装置近4年的应用结果表明,催化剂活性下降缓慢,节约了大量的硫化剂,取得了较好的效果。