金属氮化物／碳化物加氢催化剂研究进展

过渡金属氮化物与碳化物是一类间充性化合物,其结构特点决定其在催化反应上具有独特的催化效果。本文介绍了过渡金属氮化物与碳化物基本性质与作为加氢催化剂的制备进展,综述了其在催化加氢,脱氢,脱硫等方面的研究进展,并展示了重要的理论研究意义和潜在的应用前景。     

氮化物对柴油加氢脱硫影响的研究进展

分别从催化剂,工艺条件等方面介绍了氮化物对柴油加氢脱硫反应(HDS)影响的机理。介绍了氮化物对柴油HDS反应影响的动力学研究。结果表明:氮化物对柴油HDS反应具有抑制作用;在不同催化剂活性中心上和不同的工艺条件下氮化物对柴油HDS反应的影响存在差异且符合于拟一级反应动力学。氮化物对柴油HDS的影响研究,可以指导高活性催化剂的开发,寻求最优柴油HDS反应工艺。     

过渡金属氮化物催化性能研究进展

过渡金属氮化物具有类似于Pt族贵金属的催化性能得到了广泛的研究.综述了过渡金属氮化钼及助剂促进的氮化钼在加氢脱硫与脱氮、氨合成与分解、芳烃加氢和其他涉氢反应(如炔烃、烯烃加氢、丙酮缩合、肼的分解)中的应用,并介绍了其他金属氮化物(如氮化钒、氮化钴)在催化反应中的应用.     

非加氢脱除油品中碱性氮化物的研究进展

介绍了酸中和、离子液体、络合、吸附、微波等非加氢方法脱除油品中碱性氮化物的研究进展。每种方法都有其各自的优缺点,组合工艺脱氮以其投资少、操作简单、见效快的特点,将会成为油品脱氮的主要工艺方法。     

煤焦油加氢脱硫脱氮催化剂研究进展

随着石油资源的日趋减少,煤焦油加工技术受到关注。汽车尾气中含有的硫和氮污染环境,各国对油品中的硫和氮含量进行了严格限制,脱硫和脱氮成为煤焦油化工行业的重要课题。介绍煤焦油加氢工艺,综述金属碳化物、氮化物、磷化物和硫化物作为催化剂的研究现状。贵金属催化剂具有较强的加氢能力,并且通过使用强酸性载体分子筛和双金属催化剂的方法提高贵金属催化剂的抗硫毒性。碳化物催化剂具有较高的熔点和硬度、较好的机械稳定性和热稳定性,室温下几乎可以耐各种腐蚀性物质。根据金属源和碳源的不同,介绍使用程序升温还原法、气相法、热分解法和液相反应法制备碳化物催化剂的制备工艺。过渡金属磷化物催化剂具有优异的加氢脱硫和加氢脱氮选择性,添加钒的磷化物催化剂能改变加氢脱氮路径的选择性,明显增加咔唑加氢脱氮反应活性,钙的添加明显提高磷化物催化剂的加氢脱硫活性。工业上通常以ⅥB族和ⅧB族金属为活性物质制备过渡金属硫化物催化剂,使用的贵金属主要包括Pt、Pd和Ru,非贵金属主要包括W、Mo、Co和Ni等,其中,贵金属通常使用Al₂O₃或SiO₂为载体。ZrO₂载体可与活性组分产生较强的相互作用,热力学稳定性较高,但比表面积小,价格昂贵。Al₂O₃载体机械强度大,比表面积高,ZrO₂-Al₂O₃复合载体将两者的优良性能结合,可以获得性能更加优异的载体。     

过渡金属氮化物制备方法及吸氢机理研究进展

介绍了过渡金属氮化物的制备方法,讨论了影响程序升温氮化法的因素;分析了过渡金属氮化物催化剂的吸氢活性、吸附机理.与传统的过渡金属硫化物催化剂相比具有更加优异的氢吸附、活化和转移能力.在加氢脱硫、加氢脱氮和其他涉氢反应中有着广泛的应用.     

Zr改性对NiW/Al2O3催化剂加氢性能的影响

引言随着原油重质化趋势的不断加剧和环保法规对轻质油品质量要求的不断提高,劣质重油轻质化及清洁化生产成为石油加工技术发展的主要方向。溶剂脱沥青是重油脱碳改质工艺之一,得到的脱沥青油一般作为催化裂化的掺炼原料,脱沥青油中较高的硫氮含量及稠环芳烃含量容易造成催化裂化催化     

过渡金属催化剂加氢脱硫作用机理研究

从过渡金属催化剂的活性相结构和反应物在催化剂表面活性位上的吸附—催化反应机理两个方面阐述了过渡金属催化剂的催化作用研究进展,并对过渡金属催化剂催化机理研究存在的争议和未来的研究方向进行了分析。     

孔道结构对渣油加氢脱金属催化剂活性的影响

选择性制备3种不同孔道结构的渣油加氢脱金属催化剂,并进行渣油加氢脱金属和加氢脱硫活性评价。结果表明,一定量大孔(>50 nm)的存在,能够提高催化剂单位表面积的加氢脱金属活性;加氢脱硫活性与体积比表面积成正比。     

重整原料预加氢催化剂的性能评价

为了考察086-11-46催化剂（W-Ni/SiO₂-Al₂O₃）加氢脱硫、加氢脱氮性能以及处理劣质原料油的能力,分别以直馏石脑油、加入吡啶的直馏石脑油和加入催化汽油的直馏石脑油为原料油,进行了086-11-46催化剂与国内某重整原料预加氢催化剂（Mo-Co/γ-Al₂O₃）的对比评价,并以直馏石脑油为原料,考察其稳定性。结果表明,086-11-46催化剂的加氢脱硫和加氢脱氮性能均优于对比剂,更加适合处理氮含量及烯烃含量较高的劣质原料油。086-11-46催化剂在入口温度低于对比剂15 ℃的条件下,产品与对比剂相当,稳定性优于对比剂。     

Characterization of early transition metal carbides and nitrides by NEXAFS

Powder materials of a series of early transition metal (groups 4–6B) carbides and nitrides, including TiC, VC, NbC, Mo₂C, WC, TiN, VN and Mo₂N, have been characterized by nearedge X-ray absorption fine structure (NEXAFS). A comparison of the carbon and nitrogen K-edge features reveals systematic trends in the electronic properties of these materials. These results are compared to an earlier NEXAFS characterization of thin VC films produced on a single crystal V(110) surface. In addition, the NEXAFS data are also compared to existing band-structure calculations for carbides and nitrides of early transition metals.     

贵金属硫化物催化剂的制备及其在催化加氢反应中的应用

贵金属硫化物催化剂对含硫化合物加氢、加氢脱硫、加氢脱氮和卤代硝基化合物加氢等方面有特殊应用,选择性高,不易失活.总结了国内外贵金属硫化物制备方法,综述了各类贵金属硫化物在催化加氢方面的应用,并对贵金属特别是Pd的不同种硫化物种间相互转变条件进行了探讨.     

Synthesis, characterization and hydrotreating performance of supported tungsten phosphide catalysts

Supported tungsten phosphide catalysts were prepared by temperature-programmed reduction of their precursors (supported phospho-tungstate catalysts) in H₂ and characterized by X-ray diffraction (XRD), BET, temperature-programmed desorption of ammonia (NH₃-TPD) and X-ray photoelectron spectroscopy (XPS). The reduction-phosphiding processes of the precursors were investigated by thermogravimetry and differential thermal analysis (TG-DTA) and the suitable phosphiding temperatures were defined. The hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) activities of the catalysts were tested by using thiophene, pyridine, dibenzothiophene, carbazole and diesel oil as the feedstock. The TiO₂, γ-Al₂O₃ supports and the Ni, Co promoters could remarkably increase and stabilize active W species on the catalyst surface. A suitable amount of Ni (3%–5%), Co (5%–7%) and V (1%–3%) could increase dispersivity of the W species and the BET surface area of the WP/γ-Al₂O₃ catalyst. The WP/γ-Al₂O₃ catalyst possesses much higher thiophene HDS and carbazole HDN activities and the WP/TiO₂ catalyst has much higher dibenzothiophene (DBT) HDS and pyridine HDN activities. The Ni, Co and V can obviously promote the HDS activity and inhibit the HDN activity of the WP/γ-Al₂O₃ catalyst. The G-Ni5 catalyst possesses a much higher diesel oil HDS activity than the sulphided industrial NiW/γ-Al₂O₃ catalyst. In general, a support or promoter in the WP/γ-Al₂O₃ catalyst which can increase the amount and dispersivity of the active W species can promote its HDS and HDN activities.     

JT-1G/JT-4型加氢精制催化剂在逆流等温-绝热加氢精制工艺上的应用

介绍了JT-1G/JT-4型加氢精制催化剂首次配合逆流等温-绝热加氢精制工艺,用于焦化富气制氢装置的使用情况。工业应用表明,JT-1G/JT-4型加氢精制催化剂在生产过程中催化性能良好,完全满足焦化富气作为制氢原料对烯烃饱和的要求,并将有机硫加氢转化为无机硫,经氧化锌脱硫剂脱硫后,原料中硫的质量分数降至0.2×10^-6。     

First-principle calculations of the bulk properties of 4d transition metal carbides and nitrides in the rocksalt, zincblende and wurtzite structures

Bulk properties and stability of the entire series of group 4d transition metal carbides and nitrides are reported in this work. The theoretical calculations were carried out within Local Density Approximation and Generalized Gradient Approximation using the Perdew, Burke and Ernzerhof exchange correlation functional. The generalized gradient approximation predictions were found to be closer to experimental values than the local density approximation predictions. In particular, LDA predictions were found to overestimate bulk moduli properties by as much as 5.6-11.5% while equilibrium lattice constants were found to be underestimated by as much as 0.2-5% compared to experimental values. On the other hand, GGA calculations were found to overestimate the lattice parameters by 0.2-6.9%, while underestimating the bulk moduli by as much as 0.07-5%. Out of the carbides considered, TcC and RuC were found to have the highest values of bulk moduli while YC and CdC had the lowest. Similarly, out of the nitrides, MoN and TcN were found to exhibit the largest bulk moduli, indicating that they were the hardest, while CdN had the lowest value and hence relatively softer. Overall, the nitrides presented higher values of bulk moduli than the carbides, an observation that is well supported by their correspondingly shorter bondlengths. The cohesive and structural properties of the 4d transition metal carbides and nitrides are also reported.     

硫化铂族金属加氢催化剂的研究进展

硫化铂族金属催化剂为可提高有机液相加氢反应选择性的高效催化剂,能提高含羰基、羟基和卤素等官能团化合物催化加氢反应的选择性,应用广泛。综述了国内外负载型Pt和Pd等硫化贵金属催化剂的制备方法,包括采用H_2S和Na_2S无机硫化以及Ph_2S和DMSO(二甲基亚砜)等有机硫化剂进行硫化;综述了Pt和Pd硫化贵金属催化剂在有机液相催化加氢体系中的应用;并对硫化Pt族金属催化剂的硫化机理和催化机理进行探讨,展望了硫化贵金属催化剂的应用前景。     

碳化钼催化剂上的烷烃异构化研究

综述了碳化钼催化剂上长链烷烃异构化反应的研究进展和研究成果。介绍了碳化钼催化剂的制备方法、长链烷烃异构化反应机理包括酸性催化剂的异构化机理和金属-酸性双功能催化剂异构化机理,分析了此类催化剂的发展趋势和应用前景。     

Synthesis and characterization of cobalt–molybdenum bimetallic carbides catalysts

Co₃Mo₃C, Co₆Mo₆C and MCM41-supported Co₃Mo₃C catalyst are prepared by a simple one-step thermal decomposition method without the conventional temperature-programmed carburization. The resultant carbides are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscope (HRTEM) and BET surface area measurements. The as-prepared Co₃Mo₃C/MCM41 catalyst exhibits good performance in both probe reactions of hydrodesulfurization (HDS) and hydrodenitrogenation (HDN), which proves the one-step decomposition method to be an effective route for the preparation of bimetallic carbide catalyst.     

The activity of transition metal nitrides for hydrotreating quinoline and thiophene

An investigation has been conducted of the activity of AlN, BN, TiN, VN, Mo₂N, and W₂N as catalysts for quinoline hydrodenitrogenation (HDN). The activity of Mo₂N and VN for thiophene hydrodesulfurization (HDS) and the concurrent hydrotreatment of quinoline and thiophene have also been examined. Bulk AlN, BN, and TiN were obtained with low surface areas and found to be inactive for the HDN of quinoline. Bulk Mo₂N, W₂N, and VN could be obtained with high surface area. Each of these nitrides exhibited high activity for quinoline HDN, the turnover frequency for this reaction decreasing in the order Mo₂N>W₂N>VN. Highly dispersed VN supported on SiO₂ was found to have a specific activity for quinoline HDN identical to that of bulk VN. Both bulk Mo₂N and 27% VN/SiO₂ exhibit high activity for the HDS of thiophene. The behavior of these two catalysts for the concurrent hydrotreatment of quinoline and thiophene is also discussed.