Hydrocracking of Gudao Residual Oil with Dispersed Catalysts Using Supercritical Water-Syngas as a Hydrogen Source

Abstract:

Heavy oil upgrading is a very important process in the petroleum industry, but is very difficult because it has a high impurity content. A variety of heavy oil upgrading technologies have been developed in the world, including the catalytic hydrocracking process, which can process various heavy oils with a high yield of liquid products. Although this technology is one of the most widely used methods for upgrading heavy oil, the use of expensive molecular hydrogen is costly. The heavy oil upgrading technology with alternative hydrogen is very important. The catalytic hydroconversion of Gudao residue with different catalysts using water-syngas as an alternative hydrogen was investigated in this study. Hydrogen is provided in-situ for hydrocracking through the water-gas shift reaction (WGSR). The experimental results show that catalysts play a very important role in catalytic hydroconversion of Gudao residue using water-syngas as an alternative hydrogen. Addition of catalysts to residue was found to improve the distribution or properties of cracking products and inhibit the asphaltene or TI formation.     

Hydrocracking of Gudao Residual Oil with Dispersed Catalysts Using Supercritical Water-Syngas as a Hydrogen Source. Part II: The Comparison of Residue Hydrocracking in Different Hydrogen Sources

Abstract

Different catalytical hydrogen sources were compared with molecular hydrogen gas in the hydrocracking of Gudao residue in the presence of catalysts (PMA). The results showed that alternative hydrogen sources were effective in catalytic hydroconversion of heavy oil. The hydroconversion of residue in supercritical water-syngas system showed similar results when performed with molecular hydrogen.     

Hydrocracking of Gudao Residual Oil with Dispersed Catalysts Using Supercritical Water-Syngas as a Hydrogen Source

Heavy oil upgrading is a very important process in the petroleum industry, but is very difficult because it has a high impurity content. A variety of heavy oil upgrading technologies have been developed in the world, including the catalytic hydrocracking process, which can process various heavy oils with a high yield of liquid products. Although this technology is one of the most widely used methods for upgrading heavy oil, the use of expensive molecular hydrogen is costly. The heavy oil upgrading technology with alternative hydrogen is very important. The catalytic hydroconversion of Gudao residue with different catalysts using water-syngas as an alternative hydrogen was investigated in this study. Hydrogen is provided in-situ for hydrocracking through the water-gas shift reaction (WGSR). The experimental results show that catalysts play a very important role in catalytic hydroconversion of Gudao residue using water-syngas as an alternative hydrogen. Addition of catalysts to residue was found to improve the distribution or properties of cracking products and inhibit the asphaltene or TI formation.     

Hydrocracking of Gudao Residual Oil with Dispersed Catalysts Using Supercritical Water-Syngas as a Hydrogen Source. Part II: The Comparison of Residue Hydrocracking in Different Hydrogen Sources

Different catalytical hydrogen sources were compared with molecular hydrogen gas in the hydrocracking of Gudao residue in the presence of catalysts (PMA). The results showed that alternative hydrogen sources were effective in catalytic hydroconversion of heavy oil. The hydroconversion of residue in supercritical water-syngas system showed similar results when performed with molecular hydrogen.     

The Mechanism of Diesel Hydrogenation Using Supercritical Water-Syngas

Many reactions were involved in the diesel hydrorefining processes in the supercritical water-syngas system, as the mechanism of diesel hydrogenation using supercritical water-syngas was investigated by using isotopic D₂. The ²H-NMR results of hydrogenated products revealed that the supercritical water-syngas could be used as an alternative hydrogen source for diesel hydrotreating because much higher deuterium content appeared in the products. The results also indicated that the hydrogen derived from supercritical water-syngas could exchange the sulfur, so hydrogen was added to the diesel molecule.     

Kinetic Study on the Hydrocracking Reaction of Vacuum Residue Using a Lumping Model

Abstract

Based on the experimental hydrocracking of vacuum residue, a kinetic study using a lumping model was carried out to gain insight into the characteristics of catalytic reactions. The lumped species were the saturates, aromatics, resins, and asphaltenes (SARA) constituents in the residue (798 K⁺) fraction and gas, naphtha, kerosene, gas oil, vacuum gas oil, and coke in the products. The pyrite reaction favoring hydrocracking to lighter products was more temperature-dependent than that using a mixture of pyrite and active carbon. The kinetic study showed that the addition of active carbon to pyrite limited the transformation of resins to asphaltenes.     

Hydrocracking of Tetralin over Mo–Ni/Usy Dual Functional Catalysts

Abstract

Tetralin was chosen as a model compound to investigate the reaction networks and kinetics of hydrocracking of polynuclear aromatic hydrocarbons on modified zeolite Y based molybdenum–nickel dual functional catalysts using a continuous flow microreactor at 320–380°C, 8.5 MPa. According to the product distributions, the reaction network of hydrocracking of tetralin was proposed. The pseudo-first-order kinetics rate constants of each step in the network of hydrocracking of tetralin were evaluated by the nonlinear parameter estimation method. The results showed that reaction of hydrocracking of tetralin was a complicated parallel and serial reaction including hydrogenation, isomerization, and cracking (ring opening and dealkylation). The key steps of hydrocracking of tetralin, the conversion of double ring compounds and the yields of mono-ring compounds were affected by reaction temperature and acidity of supports on the catalysts.     

THE ROLES OF CARBON DIOXIDE IN METHANOL SYNTHESIS

ABSTRACT

The roles played by carbon dioxide in the chemistry of methanol synthesis over CuO/ZnO/A1₂O₃ catalysts have been experimentally investigated. It was concluded based on reaction rate measurements and thermodynamic considerations, that the two reactions that best describe the chemical system of methanol synthesis are the CO₂-hydrogenation and water-gas shift reactions. It was also found experimentally that the presence of CO₂ is vital for maintaining the catalytic activity. The significance of the study is enhanced by the fact that this was the first such investigation of the global chemistry of methanol synthesis to be based on the novel liquid phase process. It was also observed that the rates of methanol synthesis attained a maximum when the concentration of carbon dioxide in the reactor feed was controlled at a certain optimal value. The optimal CO₂ content was found to be a function of the operating temperature and syngas composition. The experimental data are especially important because the apparatus and the operating conditions have been well-defined and carefully chosen to closely simulate industrial reactors.     

Mild Hydrocracking—A Review of the Process,Catalysts, Reactions,Kinetics, and Advantages

Abstract

The demand for high quality middle distillates is increasing world wide while the demand for residue and fuel oil is decreasing. Hydrocracking is the major conversion process that meets the twin objectives of producing more middle distillates of very high quality. Since hydrocracking is a capital-intensive process, many refiners consider the option of converting their existing vacuum gas oil hydrotreating units into mild hydrocracking units. The use of mild hydrocracker bottom as FCC feedstock can improve the quality of FCC products. In view of the advantages of mild hydrocracking process, it is essential to understand the process, catalysts used, reactions, kinetics, and advantages. This article reviews recent literature on MHC process, various catalysts used, reactions involved and advantages of mild hydrocracking process in terms of improved product qualities and increased distillates. The kinetics of the mild hydrocracking process and kinetic challenges with respect to aromatic saturation have been summarized. The limitations of the process and future scope of work in this area are also discussed briefly.     

MILD HYDROCRACKING — A STATE OF THE ART

ABSTRACT

This paper is a brief, but not exhaustive review of the literature of the catalytic mild hydrocracking processes. It includes data characterizing reactivities, reaction network and kinetics of mild hydrocracking reactions. This review is designed for use as a reference for further research and development work in the field of mild hydrocracking.     

CHARACTERIZATION OF VACUUM RESIDS,HYDROCRACKED PRODUCTS AND ASPHALTENES BY PYROLYSIS-GAS CHROMATOGRAPHY (FID-FPD)

ABSTRACT

This paper describes an exploratory study on the characterization of oil heavy-end fractions through pyrolysis coupled with gas chromatography. A pulse heating pyrolyzer with a platinum-strip sample holder, directly coupled with a capillary column gas chromatograph and equipped with a universal detector (FID) and a sulfur-selective detector (FPD), was used for that purpose.

An analysis of vacuum residua, asphaltenes and resins from different crudes was made, as well as analogous fractions from the hydrocracking products of these vacuum residua. Hydrocarbon qualitative profiles (pyrograms) were very much alike for all fractions studied. However, some differences were observed in pyrogram intensity. In general, fractions from untreated samples showed more intense signals than those from the hydrotreated ones. Besides, each of the fractions from vacuum residua generated more intense pyrograms than the combination thereof (entire residue). It was possible to correlate the process-ability of a vacuum residue during hydrocracking and its hydrocarbon yield in analytical pyrolysis.     

HYDROZEN TRANSFER HYDROCRAKING OF C.PROCERA UNDER AMBIENT PRESSURE CONDITIONS TO GET VALUE ADDED CHEMICALS AND FUELS

ABSTRACT

Biomass is renewable source of energy while the reserves of petroleum arc being depleted. The latex of a potential petrocrop, Colotropis procera, a lalicifcr, arid-plant which is rich in hydrocarbon type triterpene compounds etc. was found lo be a better feed slock for thermal hydrocracking as compared to whole plant biomass inlcrms of liquid product yield. Studies of chemical reaction dynamics of the thermal cracking of latex at 200-400°C showed that the process should be termed as hydrogen-tranfer (H-T) hydrocracking of latex under ambient pressure conditions. The hydrogen rich cracked trilcrpenoids act as the H-donors in this process, where nascent hydrogen atoms and free radicals chemically plug the cracked moities to stabilise these. Latex was also coagulated and the H-T hydrocracking of the feedstock coagulum gave a higher yield of cracked oil in comparision lo that from the dried latex. A model triterpene compound, ursolic acid has been subjected to H-T hydrocracking to understand the process of hydrocracking of latex under similar conditions and it was found that triterpencs on H-T hydrocracking produced only liquid and gaseous products and no solid char. The temperature for hydrocracking of latex has been optimized to 350°C and molecular sieve was round to catalyse the H-T Hytrocraking process to yield more liquid product The distillation range of cracked latex on(CLO)Obtained from H.T Hytrocracking of C procera Latex indicated that it can be used as fuel. Moreover CLO resembled diesel fuels and was predominantly paraffinic in nature as characterised by NMR and FTIR spectral analysis. A process has been recommended for gelling value added fuels and chemicals from C. procera latex.     

An Active Carbon Catalyst Prevents Coke Formation from Asphaltenes during the Hydrocracking of Vacuum Residue

Abstract

Active carbons were prepared by the steam activation of a brown coal char. The active carbon with mesopores showed greater adsorption selectivity for asphaltenes. The active carbon was effective at suppressing coke formation, even with the high hydrocracking conversion of vacuum residue. The analysis of the change in the composition of saturates, aromatics, resins, and asphaltenes in the cracked residue with conversion demonstrated the ability of active carbon to restrict the transformation of asphaltenes to coke. The active carbon that was richer in mesopores was presumably more effective at providing adsorption sites for the hydrocarbon free-radicals generated initially during thermal cracking to prevent them from coupling and polycondensing.     

孤岛减压渣油在CO-SCW体系中催化加氢

对孤岛减压渣油在CO -SCW体系中加氢改质研究表明 ,利用CO与SCW发生的水 -气变换反应获得加氢所需氢源是可行的。在适宜的条件下 ,渣油在CO -SCW体系中改质可达到在H2 -SCW体系中改质同样的效果     

Thermal Hydrocracking Kinetics of Chinese Gudao Vacuum Residue

Abstract

The thermal hydrocracking kinetics of Chinese Gudao vacuum residue was studied in a batch autoclave reactor. The temperature ranged in 390–435°C and the initial hydrogen pressure was 7.0 MPa at 20°C. Ammonium phosphomolybdate (APM) in its dispersed phase was the catalyst. The reaction products, gas, naphtha, atmospheric gas oil (AGO), vacuum gas oil (VGO) and coke, were separated during and after experiments, and their yields vs. reaction time were obtained, for four reaction temperatures: 390, 405, 420, and 435°C. The activation energy was calculated from a traditional kinetic model to be 218.6 kJ/mol. A new kinetic model was proposed in this work that allows for the calculation of activation energy with a minimum number of three tests, each at a different temperature. This is comparable to the traditional model which requires a minimum of 12 tests; a minimum of four tests for one temperature and a minimum of three temperatures. The activation energy calculated from the new model with four tests is 229.6 kJ/mol, only 5% greater than that obtained from the traditional model. The reaction rate constants obtained from this model are also consistent with those from the traditional model.     

SEDIMENT FORMATION DURING HEAVY OIL UPGRADING

ABSTRACT

A soft coke-like substance often forms In the liquid product of visbreaking and hydrocracking processes for upgrading vacuum residue of heavy crude oil. This material usually limits the severity, or conversion of the process because it accumulates in downstream equipment. Although the amount of such material produced depends on the crude oil, it has not been possible before to correlate its production rate to chemical characteristics of the vacuum residue in a quantitative manner. In this work we show that the amount of sediment produced per unit weight of vacuum residue feed in laboratory hydrotreating experiments can be correlated with four chemical characteristic of the vacuum residue: the degree of condensed polynuclear aromaticity, the average number of alkyl-groups substituting the polynuclear aromatics, the ratio of heptane insolubles to pentane insoluble-heptane solubles, and the H/C ratio of the latter fraction. The correlation coefficient is 0.95     

Performance Evaluation Studies of First- and Second-Stage Hydrocracking Catalysts Using Kuwait Vacuum Gas Oil Feedstocks

Abstract

In a two-stage hydrocracking process, two types of catalyst are used to remove undesirable contaminants (such as S, N, hydrogenation of aromatic compounds, etc.) and convert the heavy feedstock to lighter products. In the present work, individual set of experiments were conducted to obtain information regarding activity and selectivity with emphasis on the evaluation of kinetic parameters of first- and second-stage commercial catalysts used in hydrocracking process. The performance tests were conducted in a down-flow fixed-bed hydrocracking pilot plant using a single reactor. The hydrotreating type A catalyst and hydrocracking type B catalyst were used individually with typical Kuwaiti refinery feedstocks, namely, hydrotreated vacuum gas oil (HVGO) and unconverted residual oil (UCRO), respectively. The order of reaction in this study shows first-order kinetics for HDS and HDN over CAT-A, and first-order hydrocracking conversion over CAT-B. For CAT-A the activation energies were found for HDS and HDN reactions at 22 and 27.3 kcal/gmole, while for CAT-B activation energies were 27.4 kcal/gmole.     

REACTIVITY OF SULPHUR SPECIES IN BITUMEN PITCH AND RESIDUA DURING FLUID COKING AND HYDROCRACKING

X-ray photoelectron spectroscopy (XPS) was used to determine sulphur species and their distribution in fractions of fluid coking residue (CK) and hydro-cracking residue (HC) derived from an Athabasca bitumen pitch (ABP). The major sulphur species were sulphides/mercaptans and thiophenes in each case. No sulphoxides and sulphones were detected in any non-oxidised samples. Each residua was separated into between 9 and 15 front-cut samples and a single end-cut fraction by supercritical fluid extraction and fractionation (SFEF). This approach has been used to produce different molecular weight fractions, depending on the severity of separation conditions. In the fractions from the parent Athabasca bitumen pitch about 65-80 wt% of the total sulphur occurs as thiophenes with the remainder being sulphide species. The reactivity of the sulphur species in the parent pitch was determined under mild conditions using a standard technique for selective oxidation. In this procedure sulphides are preferentially oxidized to sulphoxides while thiophenic sulphur remains unchanged; under the same reaction conditions the degree of sulphide conversion generally declined with increasing molecular weight of the fractions. Commercial catalytic hydrocracking completely removed sulphides from the front-cut fractions of the parent pitch. However, the composition of the end-cut fraction from the residua produced by this process was virtually the same as that for the comparable fraction from fluid coking. This observation demonstrates that hydrocracking has little effect on intractable heavy ends. Also, hydrocracking removed only a relatively small proportion of thiophenic sulphur. On the other hand, while commercial fluid coking removed most of the sulphides from the parent pitch the residue was enriched with thiophene compared to the parent feed. This observation demonstrates the partitioning effect occurring during coking reactions.     

渣油悬浮床加氢裂化反应中助剂的作用机制Ⅰ

 在高压釜中对辽河常压渣油（LHAR）在分散型催化剂和助剂存在下的悬浮床加氢裂化反应进行了研究,从助剂对反应体系胶体性质的影响方面探讨了助剂的作用机制。结果表明,助剂的加入能在保证渣油转化率的同时显著降低生焦量,提高反应体系的胶体稳定性;在反应升温过程中,助剂能使反应体系在较广的温度范围内保持稳定的胶体结构,提高渣油对热扰动的免疫力,从而延长第二液相——沥青质聚集相的出现时间,降低生焦量。     

LIQUEFACTION OF CELLULOSIC WASTE V. WATER FORMATION AND EVALUATION OF PYROLYTIC CHAR AS A BY —PRODUCT OF PYROLYSIS REACTION

ABSTRACT

Liquid hydrocarbon oil and water have been produced from the liquefaction of cellulosic matter present in municipal solid wastes (MSW). Gases and residual char have also been produced as by-products resulting from the pyrolysis reaction of cellulose. Quantities of water and pyrolytic char were estimated at different conditions of the process (temperature pressure of hydrogen, carrier oil medium and concentration of boric acid). From the results obtained, it was suggested that the formation of water seems to be sensitive to the operational conditions which enhance a water-gas shift reaction (in which water molecules are consumed to produce carbon dioxide and hydrogen). Decreasing of the undesired chary by-product could be achieved by increasing the concentration of boric acid that catalyzes the liquefaction reaction. Two petroleum distillates, namely gas oil and residual fuel oil, were used as carrier media of a solid refuse. It was found that fuel oil is more efficient as a buffering medium that prevents cellulose macromolecules from a rapid and complete charing during the liquefaction process. The pyrolytic char was characterized and evaluated by means of different analytical procedures and solvent extraction using petroleum ether 40–60°C and methanol. Calorific value of the pyrolytic char was found to be 4.6 Kcal g^?1 which is quite close to that of a brown coal. Dropping point test of the extracted material by petroleum ether indicated that the extract can be utilized for producing lubricating greases via saponificattion with a salt of sodium or calcium.