Nickel–molybdenum sulfide naphthalene hydrogenation catalysts synthesized by the in situ decomposition of oil-soluble precursors

Nickel–molybdenum sulfide catalysts for the hydrogenation of aromatic hydrocarbons have been prepared by the in situ decomposition of oil-soluble precursors Mo(CO)₆ and Ni(С₇H₁₅СOO)₂ in a hydrocarbon feedstock and characterized by HRTEM and XPS. The resulting Ni–Mo sulfide material exhibits high catalytic activity in the naphthalene hydrogenation reaction. An optimum Mo/Ni ratio of 1/2 has been selected.     

An Efficient Approach to Produce Clean Diesel Fuel: Development of Catalysts With Ultra-High Hydrogenation Performance

The sulfur specification for diesel fuel has been tightened exponentially over the years. To help resolve this question, the authors aimed to develop a novel unsupported Ni-Mo sulfide catalyst with ultra-high hydrogenation performance, for the production of clean diesel fuel. This catalyst was prepared directly with ammonium tetrathiomolybdate and basic nickel carbonate as the catalyst precursors through the low-temperature solid-state surface reaction. XRD and HRTEM characterization results indicate that the stacking number of MoS₂ layers is very high in the unsupported Ni-Mo sulfide. The evaluation results of model compound (dibenzothiophene) and FCC diesel fuel demonstrate that the unsupported Ni-Mo sulfide catalyst has excellent hydrodesulfurization activity and ultra-high hydrogenation performance, which can be attributed to the high stacking number of MoS₂ layers.     

二氧化钛对克劳斯反应气体吸附性能研究

目的 为了研究二氧化钛硫磺回收催化剂对克劳斯反应过程的催化机理,开展了催化剂对H₂S、SO₂和有机硫等主要反应物的吸附性能研究。方法 针对克劳斯化学反应所涉及反应物与产物在典型的二氧化钛催化剂上的吸附与脱附情况,采用微型反应器-质谱分析表征技术,研究了H₂S、SO₂产物在单独与共存条件下的吸附性能和水蒸气与硫蒸气产物的吸附性能。结果 在典型的一级克劳斯反应器操作条件下,H₂S与SO₂均能强吸附于二氧化钛催化剂上,其中,对SO₂的吸附性强于H₂S,前者的饱和吸附量是后者的3.3倍。在反应物与产物共存的状态下,催化剂对H₂S与SO₂的吸附性均会下降,硫蒸气的吸附性强于水蒸气,但扣除硫蒸气毛细凝聚产生的吸附量后,水蒸气对克劳斯反应的阻碍效应强于硫蒸气。结论 依托研究成果所开发的二氧化钛催化剂在3套硫磺回收装置上进行了工业应用。结果表明,催化剂有机硫水解效果显著,COS和CS<...     

煤-油共炼反应过程及氢转移机理

分别以1,2,3,4-四氢萘和正二十烷模拟原料油中的芳香分和饱和分,以9-苯基蒽和9-蒽甲醛为煤中多环芳烃的模型化合物,考察了模型化合物组成、反应气氛、铁基催化剂及硫化剂形态等因素对煤 油共炼反应过程的影响,研究了煤-油共炼反应机理。结果表明：铁基催化剂不仅加快了煤的裂解,促进了氢气向活性氢的转变及向煤热解中间产物转移,同时也促进了萘加氢和四氢萘脱氢的氢传递循环供氢能力,加速了氢在整个反应网络中的二次分布;有机硫化物和单质硫在高温、高压条件下均具有良好的硫化能力。氢气转变为活性氢、进行煤液化主要通过两条途径：一是重油中芳香类化合物(如萘等)的加氢;二是氢气在催化剂表面解离吸附。煤-油共炼反应以自由基反应为主,部分碳正离子可能参与反应,形成烷基化及断键重组产物。     

Promoted catalysts for hydrogenation of bicyclic aromatic hydrocarbons obtained in situ from molybdenum and tungsten carbonyls

Promoted Мo and W catalysts have been prepared in situ via thermal decomposition of precursors, oil-soluble salts Mo(CO)₆, W(CO)₆, С°C₁₆H₃₀O₄, and NiC₁₆H₃₀O₄. TiO₂, Al₂O₃, and ZrO(NO₃)₂ · 6H₂O have been used as the acidic additives. Also, Mo and W unsupported sulfide catalysts have been prepared in the presence of elemental sulfur as the sulfiding agent. The catalysts have been characterized by transmission electron microscopy and X-ray photoelectron spectroscopy. The activity of the catalysts prepared in situ has been evaluated in the hydrogenation reaction of bicyclic aromatic hydrocarbons by the example of model mixtures of 10% solutions of naphthalenes (unsubstituted naphthalene, 1- and 2-methylnaphthalenes, and 1,5- and 2,3-dimethylnaphthalenes) in n-hexadecane. The effect of the precursor/acidic oxide ratio on the activity of the formed catalyst has been found. Hydrogenation of bicyclic aromatic hydrocarbons has been conducted at a hydrogen pressure of 2 and 5 MPa and a temperature of 380 and 400°C for 2 h. Hydrogenation of the unsubstituted aromatic ring has been preferable due to the absence of steric hindrances. The degree of conversion of n-hexadecane under the reaction conditions has been 1.5–7.5% depending on the reaction temperature. It has been found that the activity of the sulfided catalyst in the conversion of 1- and 2-methylnaphthalenes is inferior to the activity of the unsulfided analogue, while partial replacement of TiO₂ by Al₂O₃ results in a decrease in the conversion of the substrates as opposed to the unsulfided catalysts, in which the use of nanocrystalline Al₂O₃ promotes an increase in the conversion.     

Hydrogenation of petroleum resins in the presence of supported sulfide catalysts

The hydrogenation of petroleum resins (PRs) in the presence of commercial NVS-A, GO-15K, AGKD-400, and AKM nickel–tungsten, cobalt–molybdenum, and nickel–molybdenum sulfide catalysts and sulfided palladium MA-15 has been studied. Features of changes in the average molecular mass (M) of the PRs in the presence and absence of sulfur compounds in the reaction medium have been determined. The highest degree of hydrogenation is achieved in dilute PR solutions with a concentration of 10–20%; an increase in the process temperature and pressure leads to an intensification of the polymer chain degradation reactions. Swelling of the polymer globules in “good” solvents (benzene, toluene) makes the polymer chains more accessible to the active sites of the catalyst and thereby leads to an intensification of both the hydrogenation and thermal degradation reactions. The process run without any solvent does not provide a sufficient degree of hydrogenation of aromatic moieties owing to the high viscosity of the reaction mass and the resulting high diffusion restrictions.     

Application of Zeolite Y-Based Ni–W Supported and In Situ Prepared Catalysts in the Process of Vacuum Gas Oil Hydrocracking

The activity of supported and in situ synthesized sulfide Ni–W catalysts based on a low-silicon zeolite Y (SiO₂/Al₂O₃ = 5.2) in the hydrocracking of vacuum gas oil is studied. It is shown that the temperature and time of reaction affect the fractional composition and the sulfur content in conversion products. It is found that the phase of tungsten sulfide as well as the mixed Ni?W?S phase active in hydrogenation are formed on the catalyst surface. It is proposed that an increase in activity for the in situ formed catalyst may be explained by a high content of sulfide phases on the catalyst surface and accessibility of the zeolite pore system.     

Quantum-Chemical and Experimental Investigation of the Catalytic Activity of Nanosized Particles of Nickel-Promoted Molybdenum Disulfide in the Hydroconversion Process

The paper is devoted to the investigation of the catalytic properties of nickel-promoted molybdenum disulfide nanoparticles in the hydroconversion process. The formation of Mo and Ni compounds under hydroconversion conditions has been studied using chemical thermodynamics methods. Quantum-chemical calculations in the cluster approximation have confirmed the catalytic activity of Mo_nNi_mS_p nanoparticles in the reactions of hydrogen activation and aromatic-ring hydrogenation. It has been shown that the main role in the activation of hydrogen and the hydrogenation of aromatic rings is played by Mo- and Ni-containing active sites of the catalyst, respectively. To confirm theoretical assumptions, the yield of products of fuel oil hydroconversion on nanosized particles of the catalyst, nickel-promoted and in situ formed molybdenum disulfide, has been investigated. It has been shown that the promotion with nickel enhances the hydrogenating functions of the molybdenum-containing catalyst and lowers coke formation during hydroconversion.     

我国硫磺回收装置排放烟气中SO2达标方案探讨

针对硫磺回收装置烟气中SO_2排放问题,指出烟气中SO_2主要有液硫脱气、加氢还原吸收尾气及其他非共性原因3个来源,提出了根据不同来源分别处理以降低排放烟气中总SO_2质量浓度的对策,形成了天然气研究院硫磺回收及加氢还原吸收尾气升级达标核心技术,主要包括H2S深度脱除溶剂CT8-26、钛基硫磺回收催化剂CT6-8和新型加氢还原吸收尾气水解催化剂CT6-11B,适用于现有带加氢还原尾气处理的硫磺回收装置,特别是具有独立加氢还原溶剂再生的装置,可将硫磺回收及尾气处理装置排放尾气中SO_2质量浓度降至100mg/m3以下,为解决硫磺回收装置尾气达标排放问题提供了新的实施方案。     

Removal of sulfur from sulfur-bearing natural gas to produce clean jet fuel

Despite the low percentage of trace level sulfur in natural gas (NG), its use as a jet fuel for reduction from the ultra level is very important. Clean and efficient NG as a fuel has major advantages and importance. If the sulfur content of natural gas will decrease in how much it is substantially upgraded. The main problems and difficulties encountered method of removing minor amounts of sulfur remaining in gases after conversion of the major portion of the sulfur content of the gas to elemental sulfur by the Claus or Stretford methods, or any method. Low-quality NG contains hydrogen sulfide, carbon dioxide, and nitrogen, but is not suitable for treatment using current conventional gas treating methods due to economic and environmental challenges. To remove sulfur from natural gas as the most common on the Claus process is applied. However, the Claus process itself is not sufficient for removal of sulfur in the ultra level. The tail gas from the Claus reaction is then passed through a catalytic hydrogenation reactor together with a supply of hydrogen to reduce the sulfur and sulfur compounds to hydrogen sulfide. As a results, hydrogen sulfide is completely removed from the NG streams by washing with alkanolamine solutions.     

The role of sulfur in modification of active sites of reforming catalysts

The features of the interaction of hydrogen sulfide with the surface of supports (alumina and silica) and catalysts (Pt/SiO₂, Pt/Al₂O₃, Re/Al₂O₃, and Pt–Re/Al₂O₃) have been studied. It has been found that the adsorption of sulfur on the supports is completely reversible. The amount of irreversibly adsorbed sulfur (S_irrev) and S_irrev/metal ratios in the catalysts after treatment in a hydrogen atmosphere at 500°C have been determined. Sulfurization reduces the dispersion of platinum to 5% and increases the amount of ionic platinum on the catalyst surface. Regarding the dehydrocyclization reaction of n-heptane, the optimal amount of sulfur required for sulfurization of the catalyst with the composition 0.25% Pt 0.3% Re/γ-Al₂O₃ (0.3% Zr) is 0.072 wt %.     

Hydrodesulfurization of Dibenzothiophenic Compounds in a Light Cycle Oil

Abstract

A hydrotreating study was conducted in a bench-scale hydroprocessing reactor, over a wide range of operating conditions of industrial interest, to look in detail at hydrodesulfurization (HDS), hydrodenitrogenation (HDN), and aromatics hydrogenation, and the interactions between these reactions. This article focuses on preliminary HDS results and some general findings. The feed used was a fluid catalytic cracking (FCC), light cycle oil (LCO) and the catalyst was a commercial NiMo/Al₂O₃ hydrotreating catalyst. The HDS results were analyzed by focusing on individual dibenzothiophenic sulfur species in the feedstock and products. Some of those species were positively identified while others were grouped into classes. It was observed that above 385°C, the assumption of irreversible pseudo-first-order reaction is not applicable for both total sulfur removal and sulfur removal of individual dibenzothiophenic species. All HDS reactions involving dibenzothiophenic structures reach a point where they are affected by hydrogenation/dehydrogenation equilibrium. Among all the 14 difficult-to-remove sulfur species identified in this work 4-methyldibenzothiophene (4-MDBT) has the highest HDS reactivity, while 4,6-dimethyldibenzothiophene (4,6-DMDBT) has the lowest HDS reactivity attributable to steric hindrance by methyl substitutes at 4 and 6 positions. It was also found that H₂S significantly reduces the reaction rates of HDS. However, this effect reaches a plateau as H₂S concentration in the gas phase increases. At low reactor temperature, HDS rates linearly increase with the increase in hydrogen partial pressure. At high temperature it reaches the limit of complete conversion.     

含硫气井络合铁脱硫工艺技术及经济适应性研究

目的 确定含硫气井采用络合铁脱硫工艺进行脱硫净化的技术及经济适应性。方法 分析了络合铁脱硫工艺的原理、流程及特点,根据含硫气井工业应用实例,研究提出了络合铁脱硫工艺的技术及经济适应性条件。结果 在技术性方面,络合铁脱硫工艺适用于任何H₂S含量的天然气脱硫,H₂S脱除率可达到99.9%以上,且脱除效果稳定,短期内不受H₂S含量波动的影响;CO₂脱除率由吸收塔运行压力及原料气中CO₂含量决定;对不同含量的甲硫醇、乙硫醇脱除率可分别达到97%、92%以上,对羰基硫的脱除率约为6.51%～35.02%;合理硫容应为药剂及电耗综合成本最低时的硫容,不同的运行工况,合理硫容也不同;工艺产生的单质硫目前主要以硫膏形式脱除及处理,对硫磺进行经济、环保的回收处理是络合铁脱硫工艺的一个难点。在经济性方面,开展了工艺完全成本分析,提出了在潜硫量为12.35 t/d的条件下工艺的经济极限H₂S含量及经济极限处理量的计算公式。结论 上述研究结果对络合铁脱硫工艺技术优选、优化及经济效...     

Nickel–molybdenum sulfide catalysts supported on an ordered mesoporous polymer for hydrogenating–hydrocracking of model biaromatic petroleum compounds

Nickel–molybdenum sulfide catalysts have been synthesized in situ in a hydrocarbon medium by the decomposition of the [(n-Bu)₄N]₂Ni(MoS₄)₂ precursor complex supported on an ordered mesoporous phenol–formaldehyde polymer in the presence of a sulfiding agent (dimethyl disulfide). The catalytic properties of the samples have been studied in a batch reactor at 380°C and a hydrogen pressure of 5.0 MPa using the example of naphthalene, 1-methylnaphthalene, and 2-methylnaphthalene. The tests have shown that the conversion of biaromatic substrates is close to quantitative and the use of dimethyl disulfide as a sulfiding agent leads to an increase in the amount of complete hydrogenation products, as evidenced by the high content of the active phase in this case.     

Hydrogenation of aromatic hydrocarbons over nickel–tungsten sulfide catalysts containing mesoporous aluminosilicates of different nature

The hydrogenation of naphthalene, toluene, and 2-methylnaphthalene used as model compounds; the hydrodearomatization of the methylnaphthalene fraction; and the hydrocracking of oil sludge over Ni–W sulfide catalysts supported on BEA/TUD, BEA/SBA-15, and ZSM-5/SBA-15 composites containing SBA-15 and TUD mesoporous silicates have been studied. Catalytic tests have been conducted in an autoclave at 300–400°C and an initial hydrogen pressure of 50–90 atm. It has been found that the highest activity is exhibited by the catalyst based on the ZSM-5/SBA-15 (1) composite prepared by the double-templating synthesis and characterized by a specific surface area of 400 m²/g and an acidity of 409 μmol/g. Thus, in the case of dearomatization of the methylnaphthalene fraction at 300°C and an H₂ pressure of 50 atm, the content of diaromatic compounds has decreased from 99.0 to 53.4%, while the amount of sulfur compounds has decreased almost 15-fold. The hydrocracking of oil sludge over NiW/ZSM-5/SBA-15 (2) at 400°C and an H₂ pressure of 90 atm has led to an increase in the content of light fractions to 52%.     

New, effective carbon dioxide and hydrogen sulfide corrosion inhibitors based on white phosphorus, sulfur, alcohols, and amines

New ammonium salts of dithiophosphoric O,O′-diesters have been obtained by simple and convenient (one pot) methods of synthesis from white phosphorus (P4), elemental sulfur, alcohols, phenols (including hydroxyethylated nonylphenols), and amines. It has been revealed that the ammonium salts of O,O-dialkyl dithiophosphoric acids obtained are effective inhibitors of carbon dioxide corrosion (protective effect Z = 90–99%) and hydrogen sulfide corrosion (Z = 88–89%) of a mild steel. It has been shown that the inhibitory activity against carbon dioxide corrosion depends on neither theamine nature nor the chain length of the alkyl substituent in the ester group and the protective effect in the case of hydrogen sulfide corrosion depends on the nature of the reactant alcohol or amine and may slightly decrease (by 10–15%). An advantage of these inhibitors is that their protective effect in carbon dioxide corrosion is enhanced with temperature (30–80°C), rather than decreases.     

Preparation of Ni—W aromatic hydrocarbon hydrogenation catalysts by breaking reverse emulsions or suspensions of a precursor in hydrocarbon feedstock

Reverse emulsions (hydrocarbon feedstock)/(aqueous precursor solution) for synthesizing aromatic hydrocarbon hydrogenation catalysts have been prepared using the water-soluble salts (NH₄)₂WS₄ and Ni(NO₃)₂ · 6 H₂O as precursors. It has been found that the optimum stabilizer for the emulsions is the nonionic surfactant SPAN-80. The resulting emulsions exhibit low catalytic activity in the hydrogenation of aromatic hydrocarbons; it has been shown that the activity of the systems in hydrodearomatization reactions is adversely affected by the presence of water. A procedure for preparing suspensions of solid precursor particles in a hydrocarbon feedstock by the removal of water from the resulting reverse emulsions has been developed. The catalytic activity of the resulting suspensions in the hydrogenation of aromatic hydrocarbons has been studied using naphthalene, 1-methylnaphthalene, and 2-methylnaphthalene as examples. It has been shown that the catalytic activity of the suspensions is higher than that of the reverse emulsions of the same composition. It has been found that the feedstock should be subjected to additional sulfurization with elemental sulfur for further sulfiding the surface of the nickel—tungsten catalyst. The W: Ni molar ratio of 1 : 1 has been found to be optimum.     

MICROWAVE INDUCED CONVERSION OF HYDROGEN SULFIDE

Abstract

The reaction of hydrogen sulfide with trona and calcium oxide in the presence of char started as soon as microwave energy was applied. However, with conventional heating, the reaction started only when the bed temperature reached approximately 540^°c. char absorbing microwave energy is rapidly heated to very high temperatures, enhancing the H₂S reaction with oxides contained in char or oxides added to char in the reaction. A 100% conversion of trona was achieved but the maximum conversion of calcium oxide was only 79%. The minimum content of char required to induce the reaction of H₂S with trona using microwave energy was 20% of char-trona mixture. When the trona content in the mixture of char-trona mixture was greater than 50%, an additional conversion of H₂S occurred to produce some amount of elemental sulfur that was deposited in the bed. This clearly demonstrates that char combined with microwave induces H₂S reaction with mineral oxides.     

Metal sulfides and elemental sulfur –catalysts for conversion of hydrocarbon systems

Certain functional characteristics of sulfide catalysts in the hydrotreating process are used to obtain ecologically clean fuels, and the hydrogenation reaction, which is an inseparable part of this process, as well as the dehydrocondensation and sulfuring action of elemental sulfur on hydrocarbons are examined.     

天然气净化厂尾气加氢催化剂认识与实践

目的 开发一种高性能的尾气加氢催化剂,以解决硫磺回收装置排放烟气中SO₂质量浓度超标的问题。方法 对天然气净化厂尾气处理装置加氢催化剂活性组分对加氢、水解和变换等主要化学反应的催化性能进行了研究。通过微反应和动态表征技术进行催化剂动力学研究,获取其加氢与水解反应的活化能与反应级数,从而提升催化剂性能。结果 研究结果表明,氢气吸附在钴钼加氢催化剂上后对SO₂加氢有一定的抑制作用,水吸附在催化剂上后对COS水解有很强的抑制和阻碍作用。依托催化剂活性组分和动力学研究结果,开发了一种加氢催化剂。结论 与镍钨和铁钼催化剂相比,该催化剂的SO₂与硫磺加氢性能、有机硫水解性能、CO变换性能均较好,适用于天然气净化厂与炼油厂的操作工况,可实现尾气处理装置排放烟气中SO₂质量浓度低于400 mg/m³的目标。