Activity of hydroprocessing catalysts prepared by reprocessing spent catalysts

In this study, two spent catalysts from the 3rd and 4th fixed beds of the atmospheric residue desulfurization (ARDS) process and one spent catalyst from the H-Oil process employing the expanded bed were used as the starting material for preparation of hydroprocessing catalysts. The spent catalysts were used either in a coked or decoked form. The procedures involved pulverizing the spent catalysts before mixing, kneading and extruding with boehmite in the presence of peptizing agent such as HNO₃. The hydrodesufurization (HDS) and hydrodemetallization (HDM) activities of the new catalysts were evaluated in the microreactor using the atmospheric residue derived from Kuwait crude. The new catalysts prepared from the spent catalysts used in the fixed bed reactors exhibited higher activity than that of commercial catalysts. The HDS activity of the new catalysts prepared from spent catalysts used in the ebullated bed reactor was much lower than that of the other catalysts. This was attributed to a high content of vanadium in the former spent catalyst. At the same time, the adverse effect of vanadium on HDM was much less evident.     

Coking threshold in hydroprocessing of asphaltenic oils

The coking propensity of asphaltenic oils is quantitatively described using experimentally determined threshold values for temperature and hydrogen pressure. Results using this method are compared with more conventional information based on solubility properties. The threshold values are shown to be more pertinent for quantitative analyses. A model exponential function based on a simple mechanistic consideration is fitted through experimental points and used to explain curve patterns.     

Characterization of dispersed hydroprocessing catalysts prepared in reversed micelles

Fe, Co and Ni particles were prepared in water/polyoxyethylene-4-laurylether/n-hexane and water/polyoxyethylene-4-laurylether/decahydronaphthalene microemulsions by reduction of metal nitrates dissolved in the water pools of the reversed micelles. The particles were mostly monodispersed with average diameters in the range 8 to 23 nm, as determined by dynamic light scattering (DLS). However, significantly smaller size estimates were obtained using transmission electron microscopy (TEM). The average DLS particle diameters increased with increased average diameter of the reversed micelles, and the diameter of the reversed micelles increased with an increase in the microemulsion water: surfactant ratio and metal ion concentration. The diameter of the reversed micelles was also dependent upon the metal dissolved in the water pool, increasing in the order Ni < Co < Fe. These trends are explained in terms of changes that occur to the microemulsion hydrophilic-lipophilic balance. Preparation of nickel and cobalt sulfides by sulfidation of the metal salt with H₂S at low temperature, yielded much larger diameter particles (average diameter 75 nm). Measurement of the activity of the sulfided catalysts showed that the Co catalyst was more active than the Ni catalyst for the hydrocracking of diphenylmethane, and Co was more effective than Fe in reducing coke yield during Cold Lake residue hydroprocessing.     

Effect of multistage hydroprocessing on aromatic and nitrogen compositions of shale oil

Geokinetics crude shale oil, a distillate and processing intermediates sampled during four-stage catalytic hydroprocessing of the distillate were analysed for total nitrogen, basic nitrogen and olefinic and aromatic contents. Successive hydroprocessing stages yielded products containing 80, 46, 16 and 2% of the nitrogen content in the feedstock. Total nitrogen, basic nitrogen and aromatic contents were also reduced. Apparent relative reactivities of aromatic hydrocarbons and nitrogen-containing compounds are in agreement with reactivities observed in model compound studies. Hydrodenitrogenation of nitrogen-containing compounds occurred concurrently with hydrogenation of non-nitrogen-containing aromatic hydrocarbons. Hydroprocessing conditions necessary for essentially complete removal of nitrogen yielded a refined oil with low aromatic content.     

活性炭负载型催化剂的制备及其在渣油加氢中的应用

渣油加氢工艺是一项重要的渣油深度转化技术,高性能渣油加氢催化剂的研发是其核心。本文介绍了一种新型渣油加氢催化剂——金属/活性炭负载型催化剂,从催化剂制备方法、反应活性、活性相等多个方面,阐述了其在渣油加氢中的应用研究情况。提出应该从增强催化剂机械强度、改进催化剂成型工艺、提高催化剂稳定性等方面改进催化剂的性能。     

Ni---Mo/Al2O3 catalysts promoted with phosphorus and fluoride

Ni---Mo/Al₂O₃ catalysts containing two promoters, fluoride and phosphorus, were studied to learn whether the benefits of both promoters could be combined to produce a superior catalyst. Initially, two series of catalysts differing in the sequence of impregnation of the additives were prepared and tested in the hydrocracking of cumene and the hydrodesulfurization of thiophene. Catalysts impregnated in the sequence phosphorus—metals (Ni and Mo)—fluoride were clearly superior to those prepared by adding first phosphorus, then fluoride and finally metals. The more effective series of catalysts was tested in the hydroprocessing of a gas oil feedstock; to determine the resistance of these surfaces to poisoning, tests were also carried out with the same feedstock spiked with quinoline. The bi-promoted catalysts retained fluoride well, and were quite effective in hydrogenation and hydrodesulfurization. They were even more effective than phoshorous-only promoted catalysts in quinoline hydrodenitrogenation.     

钼/活性炭渣油加氢催化剂的制备

渣油加氢工艺是一种渣油深度加工技术,高性能渣油加氢催化剂的研发是其核心。本文以钼酸铵为活性组分前体,采用等体积法制备了钼/活性炭催化剂（Mo/AC）,考察了制备条件如金属负载量、焙烧温度、溶液pH值等对催化剂的影响,利用XRD、SEM、XPS等手段对催化剂进行了表征。在浸渍时间4h,焙烧温度440 ℃条件下制备出负载量8%（以MoO3 计）的Mo/AC 催化剂,活性组分钼呈高度分散的单层分布,催化剂活性评价结果表明,渣油转化率可达79%,馏分油收率为75%,同时,生焦率控制在1.5%的较低水平上。     

Hydrogenation active sites of unsupported molybdenum sulfide catalysts for hydroprocessing heavy oils

The purpose of the present study was to elucidate the nature of the hydrogenation active sites on unsupported molybdenum sulfide catalysts, aimed at the improvement of the catalysts for the slurry processes. The number of hydrogenation active sites was found to relate to the “inflection” on the basal plane of the catalyst particles. The comparison of the catalytic activity to that of an oil-soluble catalyst in the hydroprocessing of heavy oils suggests that the performance of the oil-soluble catalyst was near the maximum, unless another component such as Ni or Co was incorporated.     

Life cycle of hydroprocessing catalysts and total catalyst management

Hydroprocessing catalysts based on Ni, Co, Mo and W are used in various refinery processing applications where several deactivation mechanisms become of importance (coke formation, active phase sintering, metals deposition, poisoning) in the catalyst's life cycle. The life cycle of commercial hydroprocessing catalysts is very complex and includes the catalyst production, sulfidation, use, oxidative regeneration followed by re-sulfidation and reuse or, if reuse is not possible, recycling or disposal. To understand the changes in catalyst properties taking place during a life cycle, the catalyst quality in the different stages can be best monitored by using advanced analytical techniques. The catalyst's life cycle is further complicated by numerous technical, environmental and organizational issues involved. In principle, different companies can be involved in each of the life cycle steps. Leading catalyst manufacturers, together with specialized firms, offer refineries a total catalyst management concept, starting with the purchase of the fresh catalyst and ending with its final recycling or disposal. Total catalyst management includes a broad range of services, ensuring optimal timing during the change-out process, reliable, smooth and safe operations, minimal downtime and maximum catalyst and unit performance.     

Studies on rejuvenation of spent residue hydroprocessing catalysts by leaching of foulant metals: influence of inorganic salt additives on the leaching efficiency of organic acids

A comparative study has been made on the efficiency of oxalic, malonic and acetic acids for selective removal of metal foulants (e.g. vanadium) from spent residue hydrotreating catalysts in the presence and absence of aluminium nitrate. The influence of concentration of the added salt (aluminium nitrate) on the leaching efficiency of the three acids was also studied. The treated catalysts were characterized and the improvements in surface area, pore volume and HDS activity as a result of leaching with each reagent compared. The studies revealed that addition of aluminium nitrate enhanced the leaching efficiency of each acid to a different degree. The rate of vanadium leaching by oxalic acid was increased substantially by aluminium nitrate addition whereas for acetic acid there was only a moderate enhancement in leaching rate. The enhanced leaching by the aluminium nitrate-organic acid system may be explained in terms of a synergistic mechanism involving oxidizing and complexing reactions. The improvement in surface area and pore volume achieved on rejuvenation were related to the extent of removal of vanadium from the catalyst. The HDS activity of the catalyst was also increased significantly by leaching of the deposited metals. The selectivity for vanadium leaching (V/Mo ratio) was found to be an important factor for HDS activity recovery.     

New type of tin support for hydroprocessing catalyst

TiN supported molybdenum sulfide catalysts showed much higher activity for cleavage of C-C bonds than oxide supported molybdenum sulfide catalysts, indicating the possibility of a new generation of supports for hydroprocessing catalysts.     

钴钼基加氢处理催化剂酸浸过程研究

采用响应曲面法研究废弃钴钼基加氢处理催化剂的硝酸浸出过程,目的在于将废催化剂中的钴和钼以水溶性的形式进入溶剂中以利于进行后续提纯和回收,实现固体废弃物无害化处理和资源化利用。影响酸浸过程的因素有搅拌速率、硝酸浓度、反应温度和固液比。通过响应曲面法确定主要影响因素,建立工艺参数与钴和钼浸出率的模型方程。由此模型得到的最优工艺条件下,钴浸出率大于96%,钼浸出率大于97%,表明响应曲面法得到的最优工艺参数准确可靠,可用于指导实际生产过程。     

An XPS study of the sulfidation-regeneration cycle of a hydroprocessing catalyst

The formation of sulphates in an industrial Ni-W Hydroprocessing (HP) catalyst was investigated by X-ray Photoelectron Spectroscopy (XPS). A small fluidized bed test unit with on-line sampling device was constructed to simulate industrial sulfidation and oxyregeneration processes of HP catalysts. The results obtained show that the sulfates observed on the surface of sulfided catalysts are not formed during the sulfidation process. Two oxidation processes seem to be responsible for the formation of sulfates. One of the processes happens when the catalyst is exposed to air before it is properly cooled. The other is a slow conversion at ambient temperature. The two different processes might be associated to different sulfidic species formed during the sulfidation processes, with the sulfides in the bulk of catalyst particles being more easily oxidized than the ones on the external surface of the catalyst particles. The sulfate formed during the air oxidation of sulfided catalysts, as well as that after oxyregeneration is not aluminum sulfate but nickel sulfate in both cases. XPS results also indicate that oxygenates in the feedstock are not directly involved in the sulfate formation.     

渣油加氢技术进展与发展趋势

炼油企业面临着原料油重质化和劣质化、产品绿色化和清洁化的双重压力,劣质重油成为全球未来石油资源开发的主题,重质渣油加工技术成为提升炼油企业经济效益、增加竞争力的关键环节.为应对这一挑战,炼油厂采用渣油加氢技术作为最重要的渣油加工手段之一.本文详细介绍了固定床、悬浮床、浆态床三种渣油加氢工艺技术进展与下一步发展趋势.其中...     

A comparative study for heavy oil hydroprocessing catalysts at micro-flow and bench-scale reactors

CoMo and NiMo catalysts were prepared and the catalytic activities were evaluated in fixed bed micro-flow and bench-scale reactors with different feed composition. Experiments were conducted at conditions close to those that exist in the industrial practice. Due to the different nature of the feeds, the conditions were varied with respect to both evaluation scales. The fresh and spent catalysts were characterized. Spent catalyst textural properties indicated that catalysts were deactivated and the surface area and pore volume dropped by 20–60%. The adsorption–desorption hysteresis of spent catalysts indicated that cylindrical pores are deactivated at the pore mouth and played an important role in modification by either closing one end of the pore or forming a narrow neck pore, which is indicative of the formation of “ink-bottle” type pores. Thus, the deposition of metal and carbon takes place preferentially at the pore entrance, which causes pore mouth plugging. These results are also supported by the SEM–EDAX analysis, where metal and carbon depositions are evident and taking place at the superficial region of a catalyst particle. The increase in absolute area of hysteresis is based on the catalyst's average pore diameter: the higher the average pore diameter, the lower the area of the spent catalyst. The activity and deactivation of the catalyst are discussed on the basis of catalyst porosity and deposited metal characterization. The composition of catalysts varies, considering two applications in a multi-reactor system: a CoMo catalyst for the first reactor, and a NiMo in the second reactor; the former is supported on γ-Al₂O₃ and the latter on TiO₂/Al₂O₃. As a comparison, the CoMo catalyst exhibited better hydrogenolysis while the NiMo catalyst showed better hydrogenation activity in both micro-flow and bench-scale reactors. It appears that there is a moderate effect of TiO₂ content in support on Ni and V hydrodemetallization (HDM) while hydrodeasphaltenization (HDAs) and hydrodesulfurization (HDS) activities were slightly improved when a partially hydrotreated feed, which contains more refractory compounds than virgin feedstock, was employed.     

Structural changes in catalytic hydroprocessing of syncrude coker gas oil

A method of Structural Group Analysis (SGA) was used to characterize feed and liquid products from catalytic hydroprocessing using a commercial Ni-Mo catalyst. Comparison of the structural profiles revealed significant changes in the concentration of various structural groups. SGA is a promising tool for investigating chemical changes in complex reacting systems.     

植物油加氢制备高十六烷值柴油组分研究进展

介绍了植物油加氢制备柴油的主要化学反应、工艺方法以及该项技术的工业化状况,分析了植物油直接加氢、先加氢后异构、直接脱羧工艺以及植物油与矿物柴油掺炼工艺的特点,阐述了各工艺采用的催化剂类型、工艺条件以及产品属性。指出了该领域存在的问题和研究方向。     

Studies on recycling and utilization of spent catalysts: Preparation of active hydrodemetallization catalyst compositions from spent residue hydroprocessing catalysts

Spent catalysts form a major source of solid wastes in the petroleum refining industries. Due to environmental concerns, increasing emphasis has been placed on the development of recycling processes for the waste catalyst materials as much as possible. In the present study the potential reuse of spent catalysts in the preparation of active new catalysts for residual oil hydrotreating was examined. A series of catalysts were prepared by mixing and extruding spent residue hydroprocessing catalysts that contained C, V, Mo, Ni and Al₂O₃ with boehmite in different proportions. All prepared catalysts were characterized by chemical analysis and by surface area, pore volume, pore size and crushing strength measurements. The hydrodesulfurization (HDS) and hydrodemetallization (HDM) activities of the catalysts were evaluated by testing in a high pressure fixed-bed microreactor unit using Kuwait atmospheric residue as feed. A commercial HDM catalyst was also tested under similar operating conditions and their HDS and HDM activities were compared with that of the prepared catalysts. The results revealed that catalyst prepared with addition of up to 40 wt% spent catalyst to boehmite had fairly high surface area and pore volume together with large pores. The catalyst prepared by mixing and extruding about 40 wt% spent catalyst with boehmite was relatively more active for promoting HDM and HDS reactions than a reference commercial HDM catalyst. The formation of some kind of new active sites from the metals (V, Mo and Ni) present in the spent catalyst is suggested to be responsible for the high HDM activity of the prepared catalyst.