Residue Hydrodesulfurization Research Articles

A five-lump coupled kinetic model for residue hydrodesulfurization in an ebullated bed based on hydrocracking model

Extensive attention is usually paid to sulfur removal in the residue hydrodesulfurization (HDS) process, however, the sulfur transfer (sulfur compounds are cracked into the low molecular weight sulfur compounds) is always neglected. In order to solve above problems, a five-lump coupled kinetic model for residue HDS based on hydrocracking model was proposed. A residue hydrocracking model with an absolute average error of less than 5 % was established firstly. Then the correlation between hydrocarbon conversion and sulfur transfer was established and the kinetics of sulfur transfer was described by employing this correlation. Subsequently, a coupled model for residue HDS was developed and the results showed the heavier the components were, the greater the amount of sulfur transfer would be. Compared to the conventional HDS model, the coupled model could calculate sulfur transfer and sulfur removal synchronously. For example, for components with boiling point above 600 °C, 52.4 % sulfur was converted into the hydrogen sulfide and 22.4 % sulfur was transferred within 4 h at 400 °C. The developed coupled model could provide a deep insight into the understanding of residue HDS.

Design of active phase structure with high activity and stability in residue hydrotreating reactions

The catalyst with well-dispersed (Ni)MoS2 active phase characteristic of short slab length and low stacking numbers was designed by strengthening metal-support interaction (MSI) and metal dispersion, which displayed high activity and long-term stability in real-life residue hydrodesulfurization (HDS) reactions. Furthermore, the impacts of pseudo-boehmite and catalyst calcination temperature on surface properties were thoroughly investigated. Mo equilibrium adsorption method, Al27 NMR, XRD, Raman, UV–Vis DRS, and H2-TPR characterization showed that the hydroxyl groups concentration and tetrahedral cation vacancies increased upon reducing the pseudo-boehmite extrudates calcination temperature. Increasing calcination temperature of the catalysts further strengthened MSI, resulted in well-dispersed Mo species with enhanced MSI. Therefore, well-dispersed (Ni)MoS2 active phase was acquired on novel designed catalyst. XPS coupled with HRTEM indicated that the more potential active sites, less propensity for active phase evolution and gradual increase in sulfidation degree with processing time contributed to the high HDS performance of the designed active phase. This work can deepen our understanding toward evolution pattern of active phase during residue HDS catalysts, and give guidance for developing high performance catalyst by strengthening MSI and enhancing metal dispersion.

Upgrading the catalytic activity recovery capacity of a Ni–Mo/γ–Al2O3 catalyst via a modified remanufacturing process for residue hydrodesulfurization: Effect of acid leaching conditions and process sequence

In this study, the improvement of catalytic activity recovery capacity of a modified catalyst remanufacturing process for Ni–Mo/γ–Al2O3 catalysts in residue hydrodesulfurization (RHDS) is evaluated by comparing it with our previous study. The enhancement of catalytic activity recovery is achieved by modifying the sequence and conditions of the acid leaching process in the catalyst remanufacturing process. The proposed improved process successfully restored the collapsed pore structure caused by contaminant deposition, a major deactivation factor identified in our previous study. The selective leaching of vanadium through the addition of ferric nitrate in the acid leaching process effectively addresses the issue of simultaneous removal of active species caused by excessive leaching. Consequently, the remanufactured catalyst exhibited an impressive catalytic activity recovery of 99% compared to the fresh catalyst at a reaction temperature of 395 °C, approaching a near-perfect state. Notably, the reducibility of the catalyst emerges as a key factor influencing catalytic activity recovery. The restored pore structure and selective removal of vanadium using ferric nitrate application increase the contact area between reactants and active precursors, enhancing reducibility and leading to a higher number of active sites. Additionally, a threshold effect is observed in the recovery of catalytic activity through improved specific surface area, where the enhancement of pore diameter resulting from vanadium removal on the exterior of catalyst surface becomes crucial. These findings contribute to advancing catalyst remanufacturing processes and understanding the factors influencing catalytic activity recovery.

Feasibility Assessment on Remanufacturing of Ni–Mo/γ–Al2O3 Catalyst for Residue Hydrodesulfurization

Residue hydrodesulfurization (RHDS) is a critical process in the petroleum refining industry for removing sulfur compounds from heavy residual oils. However, catalysts used in RHDS can easily be deactivated by numerous factors, leading to reduced process efficiency and economic benefits. The remanufacturing of spent catalysts can be a useful strategy for extending the lifespan of catalysts, reducing waste, and improving process sustainability. This paper proposes an effective catalyst remanufacturing process for commercial RHDS catalysts. In detail, sequential unit processes including oil washing (OW), complete incineration (CI), and acid leaching (AL) were conducted to remanufacture the spent RHDS catalysts. We also highlight some of the key challenges in remanufacturing catalysts, such as the key factors involved in catalyst deactivation. Finally, we provide future perspectives on the development of an effective catalyst remanufacturing process for RHDS, with the goal of improving the efficiency, sustainability, and competitiveness of the petroleum refining industry.

Residue Hydrodesulfurization Catalyst Research & Advancements by 2031

Residue Hydrodesulfurization Catalyst Research & Advancements by 2031

Molecular Behaviors on Asphaltenes during Atmospheric Residue Hydrodesulfurization

Molecular Behaviors on Asphaltenes during Atmospheric Residue Hydrodesulfurization

Optimal Design of Petroleum Refinery Configuration Using a Model-Based Mixed-Integer Programming Approach with Practical Approximation

We present a model-based optimization approach to determine the configuration of a petroleum refinery for grassroots (new) or existing site that considers a large number of commercial technologies particularly for heavy oil processing of crude oil residue from an atmospheric distillation unit. First, we develop a superstructure representation for the refinery configuration to encompass all possible topology alternatives comprising 96 technologies and their interconnectivities. The superstructure is postulated by decomposing it to incorporate representative heavy oil processing scheme alternatives that center on the technologies for atmospheric residual hydrodesulfurization (ARDS), vacuum residual hydrodesulfurization (VRDS), and residual fluid catalytic cracking (RFCC). We formulate a mixed-integer linear program (MILP) based on the superstructure by devising logic propositions on design and structural specifications that represent these processing options to aid convergence to an optimal refinery configu...

Effect of structure and stability of active phase on catalytic performance of hydrotreating catalysts

For environmental protection and efficient utilization of oil resources, higher requirements for the selectivity, activity and stability of hydrotreating catalysts are proposed. To effectively solve this issue, the influence of structure and stability of active phase on catalytic performance of hydrotreating catalysts was reviewed. It was realized that the active phase structure essentially depends on the extent of metal-support interaction, and can be properly designed by adjusting catalyst preparation parameters (e.g. support properties and metal precursors in the impregnating solution) and sulfidation conditions (e.g. pressure, temperature and gas composition). As the hydrotreating conditions for gasoline, diesel and residue become severer, the active phase structures need much higher stability. The selectivity of gasoline hydrodesulfurization can be notably increased by selective post-treatment of the active phase structure. Well-dispersed active phase slabs with moderate metal-support interaction are needed for highly active and stable CoMo and NiMo diesel catalysts. New generation NiMo catalyst by strengthening metal-support interaction exhibits better residue hydrodesulfurization activity and stability.

Separation of molybdenum and vanadium from oxalate leached solution of spent residue hydrodesulfurization (RHDS) catalyst by liquid–liquid extraction using amine extractant

Alamine-336, diluted with kerosene and iso-decanol, was used for separation of vanadium (IV) and molybdenum (VI) from leached solution generated by oxalic acid washing of spent residue hydrodesulfurization (RHDS) catalyst. The variation of aqueous pH represented that there was complete extraction of both vanadium (IV) and molybdenum (VI) at equilibrium pH 3.8. Both metals were extracted by two stages counter current process using 10% Alamine-336 along with 5% iso-decanol at organic to aqueous phase ratio 1:2. The metal loaded organic was then used for selective stripping of each metal. About 99% of vanadium (IV) and molybdenum (VI) was selectively stripped with 1.5M sulfuric acid and 2M ammonia solution, respectively. Both stripped solutions can be further processed for the preparation of respective oxide components of vanadium and molybdenum.

Separation and recovery of vanadium from leached solution of spent residuehydrodesulfurization (RHDS) catalyst using solvent extraction

Leached solution, generated by oxalic acid washing of spent residue hydrodesulfurization (RHDS) catalyst, was used for separation and recovery of vanadium. First of all, solvent extraction, using mixture of 20% (v/v) Alamine-336 and 5% (v/v) tri-butyl phosphate (TBP) as a phase modifier, was conducted to extract molybdenum completely at pH 0.50. Then molybdenum-free solution was used for vanadium extraction at pH 1.25 with 20% Alamine-336 and 5% TBP. Stripping of vanadium from loaded organic solution was performed with 1.5 M H2SO4 at O/A phase ratio of 5:1 where more than 99% of vanadium was stripped in two stages. The stripped vanadium solution was further processed by precipitating with ammonium hydroxide to recover ammonium-meta-vanadate which was calcined to obtain vanadium pentoxide. Finally a conceptual process was established for recovery of high purity vanadium pentoxide from oxalic acid leached solution of spent residue hydrodesulfurization (RHDS) catalyst.

Regeneration of Residue Hydrodesulfurization Catalyst

Regeneration of Residue Hydrodesulfurization Catalyst

Denitrogenation of raw diesel fuel by lithium-modified mesoporous silica

Lithium-modified mesoporous silica adsorbents (YSP-Li and MCF-Li) were prepared in order to selectively remove nitrogen compounds from residue hydrodesulfurization diesel (RHDS DSL: 271.3 ppmw of nitrogen compounds and 430.2 ppmw of sulfur compounds) provided by a refinery factory. Adsorption properties, such as the adsorption capacity, adsorption rate, and the regeneration ability toward nitrogen and sulfur compounds, were measured through batch experiments at 15 and 45 °C. They were compared with the results of previously reported Si–Zr cogel experiments. The lithium-modified mesoporous silica adsorbents exhibited a much stronger adsorption affinity for nitrogen compounds than for sulfur compounds. With regards to the adsorption capacity and the adsorption rate, the lithium-modified mesoporous silica adsorbents exhibited improved performance when compared to Si–Zr cogel. Furthermore, the Li-modified adsorbents, especially YSP-Li, could be easily regenerated by MIBK, an organic solvent.

Assessment of CO2 emissions and its reduction potential in the Korean petroleum refining industry using energy-environment models

We assessed potential future CO2 reduction in the Korean petroleum refining industry by investigating five new technologies for energy savings and CO2 mitigation using a hybrid SD-LEAP model: crude oil distillation units (CDU), vacuum distillation units (VDU), light gas-oil hydro-desulfurization units (LGO HDS), and the vacuum residue hydro-desulfurization (VR HDS) process. The current and future demand for refining industry products in Korea was estimated using the SD model. The required crude oil input amounts are expected to increase from 139 million tons in 2008 to 154 million tons in 2030 in the baseline scenario. The current and future productivity of the petroleum refining industry was predicted, and this prediction was substituted into the LEAP model which analyzed energy consumption and CO2 emissions from the refining processes in the BAU scenario. We expect that new technology and alternative scenarios will reduce CO2 emissions by 0.048% and 0.065% in the national and industrial sectors, respectively.

Mechanism of NiMoO<sub>4</sub> Formation during Oxidative Regeneration of Resid HDS Catalyst

Aggregation of the active metal components as NiMoO4 during oxidative regeneration of residue hydrodesulfurization catalyst was studied by conventional and micro X-ray diffraction (XRD). The formation of NiMoO4 was observed only on catalyst regenerated above 723 K by conventional XRD. Distribution of NiMoO4 formation through the section of a catalyst particle was investigated by micro-XRD. The center of the catalyst particle showed higher aggregation of NiMoO4 compared to the outside of the catalyst. These results indicate that NiMoO4 formation is mainly caused by temperature increase inside the catalyst due to the heat accumulation from coke burning. Since the distribution of NiMoO4 was not associated with that of vanadium, which was mainly present on the outside of the catalyst particle, vanadium did not chemically affect the active metal states.

Combustion Characteristics of Spent Catalyst and Paper Sludge in an Internally Circulating Fluidized-Bed Combustor

Combustion of spent vacuum residue hydrodesulfurization catalyst and incineration of paper sludge were carried out in thermo-gravimetric analyzer and an internally circulating fluidized-bed (ICFB) reactor. From the thermogravimetric analyzer-differential thermo-gravimetric curves, the pre-exponential factors and activation energies are determined at the divided temperature regions, and the thermo-gravimetric analysis patterns can be predicted by the kinetic equations. The effects of bed temperature, gas velocity in the draft tube and annulus, solid circulation rate, and waste feed rate on combustion efficiency of the wastes have been determined in an ICFB from the experiments and the model studies. The ICFB combustor exhibits uniform temperature distribution along the bed height with high combustion efficiency (>90%). The combustion efficiency increases with increasing reaction temperature, gas velocity in the annulus region, and solid circulation rate and decreases with increasing waste feed rate and gas velocity in the draft tube. The simulated data from the kinetic equation and the hydrodynamic models predict the experimental data reasonably well.

Life Extension of Residue Hydrodesulfurization Catalyst by Intermittent Injection of Oil-Soluble Metal Precursors to Feed Oil

A method to extend the life of a residue hydrodesulfurization (HDS) catalyst during use was devised by injecting oil-soluble metal precursors to the feed oil intermittently. The method is based on the idea that oil-soluble metal precursors are transformed to catalytically active particles and that conventional HDS catalysts capture most of them. The resulting catalyst possesses additional HDS activity. The scheme was experimentally verified with the commercial vacuum residue HDS catalyst and an atmospheric residual oil that contained 310 ppm of molybdenum naphthenate and 60 ppm of cobalt naphthenate. The catalyst, which was exposed to the metal-containing oil, captured most of the dispersed particles and its HDS activity was improved. The improved catalytic activity requires a less-severe temperature increase policy, which will extend the life of the catalyst further. A less-expensive molybdenum-containing organic compound, MOLYVAN L, was as effective as molybdenum naphthenate in improving HDS activity wh...

Pretreatment of Vacuum Residue Using HDS Unit for Production of RFCC Feedstock

The reactivity of hydrocracking and performance of vacuum residue (VR) pretreatment was studied before residue hydrodesulfurization (HDS) for successive RFCC to convert VR to gasoline. Large NiMo pores and many acid sites with moderate strength on the boria-alumina support were very favorable to enhance hydrodemetallization (HDM), HDS, and cracking of VR, which increased the yield of the lighter fraction, resulting in an atmospheric residue-like composition from VR feed for RFCC. The lifetime of the pretreatment catalyst was six months, so two alternating reactors allows one year of continuous operation of the total process without any problems. The properties of the VR pretreatment oil changed by VR pretreatment conditions were evaluated to investigate the hydrocracking reaction of VR, in particular the relationship between the reactivity of VR pretreatment oil and product properties in the HDS unit. Higher temperatures for the pretreatment led to improved quality of the product oil for successive HDS. Catalyst deactivation in the HDS unit was not influenced by the pretreatment conditions. VR conversion of more than 45% could be achieved with the combination of the VR pretreatment unit and HDS unit.

Recent studies of hydrotreating catalysts in Japan

Much effort is being made to invent noble catalysts for hydrotreatment of fuels derived from crude oils for preservation of the atmospheric environment. Studies of the catalysts for hydrotreatment in Japan, especially hydrodesulfurization of residual oils and deep hydrodesulfurization of diesel fuels, have been reviewed in this paper.

Residual oil hydrodesulfurization using dispersed catalysts in a carbon-packed trickle bed flow reactor

Residual oil hydrodesulfurization using dispersed catalysts in a carbon-packed trickle bed flow reactor

A MATHEMATICAL MODEL FOR THE CATALYST DEACTIVATION IN A COMMERCIAL RESIDUE HYDRODESULFURIZATION REACTOR SYSTEM

A mathematical model that describes catalyst deactivation in a commercial Residue Hydrodesulfurization (RDS) system is proposed. In this model, coking, metal deposition and the decrease of effective diffusivities are all considered, so that it can predict the dynamics of catalyst activity during a long run of an RDS system. The RDS system under consideration here is a complex trickle bed reactor system with four adiabatic reactors in series, between which the oil is quenched by hydrogen to prevent the catalysts in the next reactor from being damaged by high temperature. This article shows that by incorporating a catalyst deactivation model into the overall reactor system model, the predicted catalyst aging curve assumes the “S” shape, characteristic of real RDS system. The model prediction are compared with data from an operating refinery and the agreement is pleasing. KEYWORDS Residue Hydrodesulfurization(RDS) Apparent activity Catalyst deactivation curve Pore radius.