Hydrocracking Of Heavy Oil Research Articles

Slurry-phase hydrocracking of heavy oil and model reactant: effect of dispersed Mo catalyst

Thermal hydrocracking and catalytic hydrocracking of heavy oil and model reactant have been carried out to investigate the effect of dispersed Mo catalyst on slurry-phase hydrocracking. The XRD and XPS patterns suggested that the major existence form of dispersed Mo catalyst in slurry-phase hydrocracking was MoS2. Experimental data revealed that the conversion of feedstock oils and model reactant increased with the presence of catalyst, while the yields of light products (gas, naphtha) and heavy products (vacuum residue, coke) decreased, the yields of diesel and vacuum gas oil increased in the meantime. Besides, the yields of aromatic hydrocarbon and naphthenic hydrocarbon in naphtha fraction decreased. Effect parameters R G (the ratio of i-C4H10 yield to n-C4H10 yield) and isoparaffin/n-paraffin ratio were proposed to study the reaction mechanism of slurry-phase hydrocracking, the smaller effect parameters showed that there was no carbonium ion mechanism in slurry-phase hydrocracking, which still followed the free radical mechanism, and that the isomerization ratio of products decreased with the presence of Mo catalyst.

ChemInform Abstract: A Review of Experimental Procedures for Heavy Oil Hydrocracking with Dispersed Catalyst

AbstractReview: 149 refs.

Preparation of Co–Mo supported multi-wall carbon nanotube for hydrocracking of extra heavy oil

In this study, multi-wall carbon nanotube (MWCNT) supported Co–Mo nanocatalysts with changes in synthesis steps, one and two-step, were prepared through impregnation to be used in extra heavy oil hydrocracking process. In both of the synthesized nanocatalysts, the Co/Mo weight ratio was 1/3. The nanocatalysts were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and accelerated surface area and porosimetry (ASAP) methods. The results showed that the nanocatalysts prepared through a two-step impregnation method had higher surface area and pore volume than the other synthesized nanocatalysts.The nanocatalysts were used in hydrocracking process under mild operating conditions, 260–300°C and at H2 initial pressure of 5MPa. Hydrocracking of extra heavy oil was conducted in an autoclave reactor. The results indicated that both nanocatalysts were capable of hydrocracking heavy oil at mild operating conditions. However, the nanocatalysts synthesized through the two-step impregnation exhibited higher performance, better heavy oil to light oil conversion, and better sulfur removal than the other methods. This superiority is due to the nanocatalyst's structure and better distribution of metal clusters on the support.

Hydrocracking of Heavy Oil by Means of In Situ Prepared Ultradispersed Nickel Nanocatalyst

This work adopts a water-in-oil (w/o) microemulsion method for the in situ preparation of ultradispersed metallic nickel (Ni0) nanocatalyst in heavy oil and assesses its hydrocracking activity. Catalyst preparation involved reducing Ni2+ added to the water pools of the heavy oil matrix in the form of aqueous Ni(NO3)2 solution using hydrazine. The volume of the aqueous precursors was limited to values which corresponded to visually stable single heavy oil phase. The product particles were collected by addition of toluene and characterized using XRD, TEM, and EDX. These techniques confirmed the formation of nickel nanoparticles of 22 ± 5 nm mean diameter. The hydrocracking activity of the as-prepared ultradispersed catalyst was evaluated using a semibatch reactor setup under 110 bar of hydrogen and 370 °C. Although no presulfiding was performed, XRD of the spent catalyst confirmed the formation of Ni3S2 nanoparticles with a mean particle size of the same range as the Ni0 particles. Results showed 2-fold imp...

A review of experimental procedures for heavy oil hydrocracking with dispersed catalyst

This paper summarizes the technical knowledge necessary to study the hydrocracking of heavy oil with dispersed catalysts. Chemical kinetics aspects of the hydrocracking of heavy oil reaction are reviewed. The discussion also includes a description of the experimental setups, operation modes and suitable reactors for conducting heavy oil hydrocracking experiments. Reactors and their hydrodynamics are described in order to establish the more appropriate operating conditions to perform the experiments. The most common catalyst precursors used in the reaction are listed as well as the analytical techniques employed in characterizing and quantifying gas, liquid and solid samples. Procedures for pretreatment of feed, catalyst dispersion and sulfurization of catalyst precursors are also presented

Investigation on Asphaltene Structures during Venezuela Heavy Oil Hydrocracking under Various Hydrogen Pressures

Venezuela heavy oil under various hydrogen pressures has been hydrocracked to investigate the variation of asphaltene components during reaction. Asphaltenes have been isolated from the product and analyzed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and nuclear magnetic resonance (NMR). The experimental data revealed that the interlamellar spacing and interchain spacing of the asphaltenes increased while the layer diameter decreased with the hydrogen pressure increasing. At the same time, the amount of aromatic carbon and alkyl carbon of the asphaltenes decreased gradually and the amount of naphthenic carbon increased. As the hydrogen pressure increased, the substitution ratio and the condensation degree parameter (HAU/CA) of the aromatic system in the periphery increased gradually and the replacement index and peri-position condensation index of asphaltenes decreased obviously.

Hydrocracking of Maya Vacuum Residue with NiMo Catalysts Supported on Mesoporous Alumina and Silica–Alumina

Hydrocracking of heavy oils poses greater challenges than that of lighter feeds in terms of catalyst properties and resistance to deactivation. The development of larger pore size catalysts may be beneficial to improve their effectiveness toward cracking the larger molecules present in these feedstocks. Mesoporous alumina and mesoporous silica–alumina (MSA) with different textural properties were used as supports to prepare NiMo-based catalysts. These catalysts were tested in the hydrocracking of a vacuum residue (VR) from Maya crude oil and compared against a commercial Al2O3 catalyst. The conversion of VR and asphaltenes into lighter hydrocarbons obtained with supports and catalysts was determined, and the coke deposition process was studied. The in-house developed catalysts were utilized for two consecutive runs with fresh feed to evaluate coke deposition during reutilization of the materials. It was found that coke deposition occurred mainly in the first run, with carbonaceous deposits stabilizing for all the catalysts during their reutilization. Reaction temperature had an important impact on conversions and product distributions, with higher reaction temperatures accounting for higher VR and asphaltene conversions at the expense of a large increase in gas yields. Although the NiMo/Al2O3 catalyst achieved similar VR conversion to the other catalysts, it displayed higher asphaltene conversion with lower coke deposition and a reduced gas yield. The effectiveness of this catalyst can be attributed to its larger pores that can allow better diffusion of asphaltene molecules than MSA or NiMo/MSA as well as the commercial catalyst.

Kinetic model for hydrocracking of heavy oil in a CSTR involving short term catalyst deactivation

A five-lump model previously reported in the literature was used for the kinetic modeling of an atmospheric residue (312°C+) hydrocracking. The model has ten reaction rate coefficients, makes a distinction of different hydrocarbon groups based on boiling ranges, and includes the following lumps: unconverted vacuum residue (538°C+), vacuum gas oil (VGO; 343–538°C), middle distillates (204–343°C), naphtha (IBP-204°C), and gases. The kinetic study was carried out in a CSTBR at the following operating conditions: 380–420°C, 100kgf/cm2, 5000std ft3 H2/bbl of oil, and 0.5–1.25mlfeed/(mlcath). Experiments were performed with a commercial size tetra lobular catalyst. The model also incorporates the effectiveness factor, and a time-dependant deactivation function for obtaining the intrinsic kinetic parameters. The hydrocracking of vacuum residue, VGO and middle distillates exhibited a higher selectivity toward the heavier lumps as temperature is increased. The predicted product composition is in good agreement with experimental values with an average absolute error less than 5%.

Kinetics of thermal hydrocracking of heavy oils under moderate hydroprocessing reaction conditions

Thermal hydrocracking (non-catalytic) of a heavy oil residue was studied in a bench-scale fixed-bed reactor unit. The reaction temperature and the ratio of total mass flow to inert material volume were varied from 380 to 420°C and from 0.23 to 0.65gTcmSiC-3h-1 respectively, at constant hydrogen-to-oil ratio (890m3/m3) and pressure (100kg/cm2). The reactor was loaded with silicon carbide as inert material. The results from the simulated distillation of the feed and of the products were used to calculate conversion of vacuum residue and the yield of each specific fraction (vacuum gasoil, middle distillates, naphtha and gases). The lumping approach was used to study the kinetics of the hydrocracking reaction. The results confirm that hydrocracking reactions proceed by cascade mechanism from the heavier fractions to the lighter fractions. Naphtha does not hydrocrack to form gases at the operating conditions studied. The reaction order that better fits the experimental data of vacuum residue conversion is two with activation energy of 42kcal/mol.

Elimination of the negative effect of nitrogen compounds by CO2–water in the hydrocracking of anthracene

Development of green and efficient methods to eliminate the negative effect of the nitrogen compounds in the hydrocracking of heavy oils is of great importance, and model compounds (e.g. anthracene) are often used to get the related chemical knowledge. In this work, we studied the effect of CO2 and/or water on the hydrocracking of anthracene catalyzed by NiFe + HZSM-5 in the presence of nitrogen compounds. Using 2-methylimidazole as the nitrogen compound, the influences of different factors, such as the amount of water, amount of the nitrogen compound, and the Si/Al molar ratio of HZSM-5 on the reaction were investigated. It was demonstrated that without water and CO2 the nitrogen compound had significant negative effect on the hydrocracking by poisoning the catalyst. Water or CO2 could reduce the negative effect to a considerable degree. Interestingly, CO2–water mixture could eliminate the negative effect completely, and the yields of the products could be even higher than that in the absence of the nitrogen compound. Further study indicated that some other nitrogen compounds like pyrrole, pyridine and 2-methylpyrazine also had a positive effect on the hydrocracking in the presence of CO2–water mixture. The reason for this phenomenon was discussed.

Preparation and Application of an Oil-Soluble CoMo Bimetallic Catalyst for the Hydrocracking of Oil Sands Bitumen

An oil-soluble CoMo bimetallic catalyst was prepared for an application to hydrocracking reaction of heavy oil. Layered ammonium cobalt molybdate was synthesized by precipitation, and the bimetallic dispersed catalyst was prepared by coating the layered material with oleic acid as an organic ligand. The prepared catalyst was characterized by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The oleic acid added during the preparation step was found to be chemisorbed as a carboxylate onto the particles. The activities of the CoMo bimetallic dispersed catalyst were compared to those of other monometallic dispersed catalysts and simple physical mixtures of these catalysts in an effort to evaluate the applicability and synergistic catalytic effect of the CoMo bimetallic dispersed catalyst in the hydrocracking of heavy oil. The catalyst promoted the asphaltene and sulfur conversion activities, maximizing the yield of the liquid product. These results suggest that a bimetallic effect can be created when two metals are chemically bound to form a single catalyst.

On the detailed solution and application of the continuous kinetic lumping modeling to hydrocracking of heavy oils

The solution of the continuous kinetic lumping model is reviewed with detail in this work by solving the mass balance equation that describes a particular hydrocracking process of crude oil at moderate reaction conditions. The main aspects of the continuum description are discussed and others are addressed for future research. Not all model parameters can reach the convergence directly but an iterative procedure is necessary. Arbitrary selection of the possible highest boiling point compound in the mixture can arrive to different values of parameters of the continuous kinetic lumping approach and some discussion about its determination is provided.

A protein inspired RNA genetic algorithm for parameter estimation in hydrocracking of heavy oil

Hydrocracking is a crucial process in refineries and suitable model is useful to understand and design hydrocracking processes. Simulating the procedure from RNA to protein, a protein inspired RNA genetic algorithm (PIRGA) is proposed to estimate the parameters of hydrocracking of heavy oil. In the PIRGA, each individual is represented by a RNA strand and a new fitness function combining traditional fitness value and individual ranking is employed to maintain population diversity. Furthermore conventional crossover operators are replaced by RNA-recoding operator and protein-folding operators to improve the searching ability. An adaptive mutation probability in the PIRGA makes the algorithm have more chance to jump out of local optima. Numerical experiments on seven benchmark functions indicate that the PIRGA outperforms other genetic algorithms on both convergence speed and accuracy greatly. 10 parameters are obtained by the PIRGA and the kinetic model for hydrocracking of heavy oil is established. Experimental results reveal that the predictive values are in good agreement with the experimental data with relative error less than 5%. The effectiveness and the robustness of the model are also validated by experiments.

Dynamic study on the dispersion of water-soluble catalysts for heavy-oil hydrocracking

The dispersion of water-soluble salts in heavy-oil residues has been analyzed by means of a microscopic image analyzer, and the effectiveness of the dispersion of the water-soluble salts in the residues has been evaluated in terms of the dispersion parameter. A dynamic dispersion model has been built on the basis of a previous model, and the dispersion process of the water-soluble salts in the residues has been studied with respect to time. The results have indicated that the model adequately rationalizes the observed changes in solubility in the different residues; the dispersion parameter of a water-soluble Mo salt shows a temporal change in accordance with a Lorentzian mathematical model in an oil sample designated as Kelamay heavy oil, that of a water-soluble Co salt changes in accordance with a Boltzmann model in a sample designated as Daqing heavy oil, and that of a water-soluble Ni salt changes in accordance with a Gaussian model in Liaohe heavy oil.

A Review of Process Aspects and Modeling of Ebullated Bed Reactors for Hydrocracking of Heavy Oils

The main characteristics of ebullated bed reactors have been reviewed in this work. Key factors of the application of these reactors to hydrocracking of heavy petroleum fractions, such as sediments formation, catalyst attrition and catalyst deactivation, have been clearly discussed. Mathematical representation of ebullated bed systems has been organized into hydrodynamics, scaling down and reactor modeling. Only a few reports dealing with the topic of this review were found in the literature, which employ different levels of sophistication to establish the model equations. These literature reports were summarized and properly discussed, from which it has been recognized that modeling of ebullated bed reactors is a complex task and deserves more attention.

Application of continuous kinetic lumping modeling to moderate hydrocracking of heavy oil

The continuous lumping approach was used for modeling of hydrocracking of heavy crude oil at moderate reaction conditions. The model parameters were estimated from experimental results obtained in an isothermal fixed bed reactor at different temperatures (380–420 °C) and space velocity (1.5, 0.5 and 0.33 h −1) at constant pressure and hydrogen-to-oil ratio of 9.8 MPa and 5000 ft 3/bbl respectively. Four model parameters showed linear trend with temperature whereas only one parameter remained almost constant. The optimized values of model parameters were employed to predict results obtained at different reaction conditions from which they were derived. Comparisons between experimental data and predictions using the continuous lumping kinetic model showed good agreement with average absolute error lower than 5%.

Study on a Water-Soluble Catalyst for Slurry-Phase Hydrocracking of an Atmospheric Residue

The slurry-phase hydrocracking of Karamay atmospheric residue (AR) with water-soluble dispersed catalyst was studied, and the catalyst after being separated from the reaction products was analyzed using laser Raman spectroscopy (LRS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) to identify the crystal structure of the catalyst. In this paper, the catalytic functions of molybdenum, nickel, and iron were studied respectively during the slurry-phase hydrocracking while using diphenylmethane as the model compound and AR from Karamay crude as the feedstock. The test results showed that, during the slurry-phase hydrocracking of heavy oil, the metal sulfides entered into chemical reactions with the free-radical intermediate H• formed on the catalyst surface. The free-radical intermediate H• formed on the catalyst surface could react with the free radicals of large molecules and could suppress coke deposition.

Preparing and characterizing the active carbon produced by steam and carbon dioxide as a heavy oil hydrocracking catalyst support

Active carbon was prepared from Yallourn brown coal char using steam and carbon dioxide activation in a laboratory rotary kiln. The activation rate with steam was faster than that with carbon dioxide. The pore structure of the active carbons was characterized using the nitrogen isotherms at 77 K. The pore volume and specific surface area of the active carbon increased with the carbon burn-off, and compared to carbon dioxide, steam activation produced active carbon that was richer in mesopores by increasing the pore size from micropores to mesopores. The porosity of the active carbons was related to the ability to adsorb maltene, the normal hexane-soluble fraction, in the vacuum residue of petroleum crude. The steam-activated carbon rich in mesopores had a greater ability to adsorb maltene, which consists of large-molecular-weight hydrocarbons.

A Review of Slurry-Phase Hydrocracking Heavy Oil Technology

The technologies of slurry-phase hydrocracking of heavy oil and the latest development of dispersed catalysts were reviewed. Catalysts for slurry-phase hydrocracking of heavy oil have undergone two development phases, that is, heterogeneous solid powder catalysts and homogeneous dispersed catalysts. The homogeneous dispersed catalysts are divided into water-soluble dispersed catalysts and oil-soluble dispersed catalysts. Solid powder catalysts have low catalytic activity, which will produce a large number of solid particles in bottom oil; thus it is difficult to dispose and utilize. Dispersed catalysts are highly dispersed and have greater surface area to volume ratio. Therefore, they show high catalytic activity and good performance. They are desirable catalysts for slurry-phase hydrocracking of heavy oil.

1-3 重質油のスラリー床型水素化熱分解((2)重質油改質・アップグレーディング,Session 1 石炭・重質油等,研究発表(口頭発表))

1-3 重質油のスラリー床型水素化熱分解((2)重質油改質・アップグレーディング,Session 1 石炭・重質油等,研究発表(口頭発表))