MILD HYDROCRACKING OF VACUUM GAS OILS TO IMPROVE FCC PERFORMANCE AND MAXIMIZE DISTILLATE YIELDS

ABSTRACT

A pilot plant study was conducted on mild hydrocracking of heavy vacuum gas oils derived from two different crude sources over a commercially available catalyst to determine the possibility of utilizing mild hydrocracker bottoms as fluidized catalytic cracking feedstock along with improved middle distillate yields. The mild hydrocracking experiments were conducted at 390°C, 60 kg/cm², 1.0/h liquid hourly space velocity and H₂/oil ratio of 390 l/l in a pilot plant trickle bed reactor using two catalyst beds for pretreatment and mild hydrocracking reactions. The experimental results showed that mild hydrocracking would result in valuable middle distillates with low sulphur and nitrogen content. With research octane number of 78, the naphtha obtained from mild hydrocracking was found to be a good blending stock for gasoline pool. The middle distillate fraction (140–370°C) obtained from mild hydrocracking product was found to have cetane number in the range of 48–54. The bottom product from mild hydrocracking of heavy vacuum gas oils was found to be a good feedstock for fluidized catalytic cracking unit because of its low sulphur, nitrogen and aromatic contents. The data obtained from pilot plant studies showed that the processing of mild cracker bottom in FCC unit would result in better quality fuels.     

Application of a Continuous Kinetic Model for the Hydrocracking of Vacuum Gas Oil

Hydrocracking is one of the most versatile petroleum refining processes for production of valuable products including gasoline, gas oil, and jet fuel. In this paper, a five-parameter continuous lumping model was used for kinetic modeling of hydrocracking of vacuum gas oil (VGO). The model parameters were estimated from industrial data obtained from a fixed bed reactor operating at an average temperature of 400°C and residence time of 0.3 h. Product distributions were obtained in terms of the weight fraction of various boiling point cuts. The model parameters were estimated using the Nelder-Mead optimization procedure and were correlated with temperature. Comparison of experimental and predicted product distributions indicated that the model was successful in predicting the products from hydrocracking reactions.     

MILD HYDROCRACKING OF VACUUM GAS OILS TO IMPROVE FCC PERFORMANCE AND MAXIMIZE DISTILLATE YIELDS

A pilot plant study was conducted on mild hydrocracking of heavy vacuum gas oils derived from two different crude sources over a commercially available catalyst to determine the possibility of utilizing mild hydrocracker bottoms as fluidized catalytic cracking feedstock along with improved middle distillate yields. The mild hydrocracking experiments were conducted at 390°C, 60 kg/cm², 1.0/h liquid hourly space velocity and H₂/oil ratio of 390 l/l in a pilot plant trickle bed reactor using two catalyst beds for pretreatment and mild hydrocracking reactions. The experimental results showed that mild hydrocracking would result in valuable middle distillates with low sulphur and nitrogen content. With research octane number of 78, the naphtha obtained from mild hydrocracking was found to be a good blending stock for gasoline pool. The middle distillate fraction (140-370°C) obtained from mild hydrocracking product was found to have cetane number in the range of 48-54. The bottom product from mild hydrocracking of heavy vacuum gas oils was found to be a good feedstock for fluidized catalytic cracking unit because of its low sulphur, nitrogen and aromatic contents. The data obtained from pilot plant studies showed that the processing of mild cracker bottom in FCC unit would result in better quality fuels.     

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.     

Slurry-phase catalytic hydrocracking of mazut (heavy residual fuel oil) using Ni-bentonite

Abstract

In this work, Ni-bentonite catalyst was synthesized through exchange method. The synthesized catalyst and the pristine clay were characterized by XRD, XRF, TGA/TDA, TEM, EDX-mapping, nitrogen adsorption-desorption at ?196?°C, H₂-TPD and NH₃-TPD. The catalytic efficiency of the dispersed nickel catalyst toward the hydrocracking of mazut (heavy residual fuel oil) under reduced pressure has been evaluated. The experimental results showed increasing yield of middle distillate fraction to 71?wt.% as the reaction temperature raised to 430?°C under pressure 2.0?MPa.     

Synthesis and characterization of Ni-Mo catalyst using pea pod (Pisum sativum L) as carbon support and its hydrotreating potential for gas oil,Jatropha oil,and their blends

Ni-Mo catalyst was prepared directly on pea pod using boric acid as a surface modifying agent. The BET surface area of the pea pod derived carbon based catalyst was found to be 380 m²/g. The activity of the inventive catalyst was tested in micro down flow reactor for hydrotreating of gas oil, 20% Jatropha oil in gas oil at the temperature range of 330–370°C, 90 bar H₂ pressure and space velocity of 1 h^?1 followed by Jatropha oil at 370°C, and keeping the other process parameters constant. The gas oil hydrotreating activity of the catalyst studied at temperatures below 370°C was found to be lower than that of the commercial alumina- and carbon-supported Ni-Mo catalysts; however, the activity was found to be comparable at 370°C.     

EFFECTS OF HYDROTREATING COKER LIGHT GAS OIL ON FUEL QUALITY

ABSTRACT

Coker light gas oil (LGO) derived from Athabasca bitumen was hydrotreated in a fixed bed reactor using two commercial NiO-MoO₃/Al₂0₃ catalysts. The effect of temperature on product quality was investigated in a pilot plant between 330 and 390 °C at 12.4 MPa, space velocity of 0.5 Ir1 and 700 liter of hydrogen per liter of coker LGO (L/L). The product quality was monitored by ^I3C NMR spectroscopy, elemental analysis, density and distillation techniques.

The data showed that coker LGO can be hydrotreated using nickel-molybdenum catalysts at 350 °C, 0.5 h¹, 12.4 MPa and 700 L/L to meet the diesel product specifications, namely, 0.5 wt % sulfur, 20% aromatics and cetane index of 40. The cetane index improvement and aromatic saturation, which are affected by thermodynamic equilibrium at temperature higher than 370?°C, could reach 29 and 86% respectively. The cetane improvement was attributed to aromatic saturation and hydrocracking with hydrogen consumption ranging from 215-340 L/L. The Ketjenfine KF-840 catalyst was found slightly better performance than Procatalyse HR-348 catalyst.     

Activity of Supported and In Situ Synthesized Beta Zeolite Catalysts in the Hydrocracking of Vacuum Gas Oil

Nickel–tungsten sulfide catalysts synthesized by two methods—conventional supporting of active components and in situ synthesis in the reaction medium—have been characterized by a complex of physicochemical analysis methods. The catalysts have been compared with respect to their activity in the hydrocracking of vacuum gas oil (VGO) in a batch mode under conditions of varying temperature (380–400°C), reaction time (3–10 h), and zeolite (4–8 wt %) and NiW content (0.85–1.7 wt %). It has been shown that the in situ synthesized catalyst is superior in the hydrocracking and hydrodesulfurization of VGO owing to the accessibility of active catalyst sites.     

Hydrocracking of Polyolefin Thermal Cracking Waxes Over Ni-loaded Molecular Sieve Catalysts

The hydrocracking of thermal cracking waxes obtained from pyrolysis of polyolefin at 360°C for 120 min has been studied using Ni-loaded molecular sieves catalysts. According to XRD, TPR, and BET data, the presence of nickel oxide did not seem to damage the crystalline framework of the catalytic supports. Hydrocracking experiments were carried out in a stirred autoclave reactor at 300°C for 120 min under 2.0 MPa of hydrogen. The results suggested the existence of a balance between the acid and metal function over bifunctional catalysts, which affects hydrogenation and hydroisomerization of thermal cracking waxes. Hydrocracking reactions took place extensively over mixture of Ni/HBeta and ZSM-5, leading toward higher fractions of gases (30.2%) and diesel (23.5%). The higher fractions of gasoline (33.5%) and lube base oil (19.0%) were obtained over mixture of Ni/HSAPO-11 and ZSM-5. In contrast, hydrocracking reaction occurred in a lower extent over mixture of Ni/NMCM-41 and ZSM-5, which produces lube base oil with lower pour point (–10°C), gasoline and diesel with lower bromine numbers (1.1 and 0.8 g Br₂/100 g sample). The viscosity index of lube base oil was in the range of 131–171 over all three mixed catalysts.     

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.     

Kinetics and Selectivity of Asphaltene Thermal Cracking,Thermal Hydrocracking,and Catalytic Hydrocracking

Abstract

A pentane-insoluble asphaltene was processed by thermal cracking, thermal hydrocracking, and catalytic hydrocracking in a microbatch reactor at 430°C. The experimental data of asphaltene conversion fit second-order kinetics adequately to give the apparent rate constants of 1.704 × 10^?2, 2.435 × 10^?2, and 9.360 × 10^?2 wt frac^?1 min^?1 for the above three cracking processes, respectively. A three-lump kinetic model is proposed and solved to obtain rate constants of parallel reactions of asphaltenes to produce liquid oil (k₁) and gas + coke (k₃) and a consecutive reaction from liquid to gas + coke (k₂). The value of k₁ is 1.697 × 10^?2, 2.430 × 10^?2, and 9.355 × 10^?2 wt frac^?1 min^?1; k₂ is 3.605 × 10^?2, 2.426 × 10^?2, and 6.347 × 10^?3 min^?1; and k₃ is 6.934 × 10^?5, 5.416 × 10^?5, and 4.803 × 10^?5 wt frac^?1 min^?1 for asphaltenes thermal cracking, thermal hydrocracking, and catalytic hydrocracking, respectively. Analysis of selectivity shows that the catalytic hydrocracking process provides the highest liquid production, and the coking process provides the highest coke formation, as expected. An induction period of coke formation was found to increase from thermal cracking to thermal hydrocracking to catalytic hydrocracking process.     

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%.     

Isolation of adamantane hydrocarbons from Cenomanian oil of the Russkoe oilfield

Adamantane hydrocarbons have been isolated from Cenomanian heavy naphthenic oil of the Russkoe field using the thiocarbamide adduction method. Steam distillation of the oil has given a fraction (boiling range 105–150°C) containing 0.36 wt % adamantane, from which a concentrate containing 18.2 wt % C₁₀–C₁₄ adamantane derivatives has been obtained. Adamantane and its derivatives in the crude oil, oil fractions, and concentrate have been identified, and adamantane has been quantified using the gas chromatography—mass spectrometry technique.     

A study of the catalytic steam cracking of heavy crude oil in the presence of a dispersed molybdenum-containing catalyst

The features of the steam cracking of heavy crude oil in the presence of a dispersed molybdenumcontaining catalyst are studied. The effect of water, the catalyst, and process conditions on the composition and properties of the products of the thermal conversion of heavy crude oil is determined in experiments on thermal cracking, steam cracking, catalytic cracking in the absence of water, and hydrocracking. A complex analysis of the resulting products is conducted; the catalyst-containing solid residue (coke) has been studied by XRD and HRTEM. The effect of the process temperature (425 and 450°C) and time on the yields and properties of the resulting products is studied. The efficiencies of hydrocracking and steam cracking for the production of upgraded low-viscosity semisynthetic oil are compared; the fundamental changes that occur in the catalyst during the studied processes are discussed. Some assumptions about the principle of the catalytic action of the molybdenum-containing catalyst in the steam cracking process are made.     

Supercritical water gasification of a heavy fuel oil

In this research, the supercritical water gasification for a sort of heavy fuel oil, Mazut, has been investigated. Mazut was modeled with a 33-pseudo-component using the corresponding distillation curve. In a reactor, the equilibrium reactions were simulated using the Gibbs free energy minimization method. A parametric study was performed on this system. The parameters were included mass fraction of fuel and pressure and temperature of the gasifier. Two approaches were investigated, one with constant pressure (P = 22.1 MPa) and the other with constant temperature (T = 600°C), varying the other two parameters. H₂ production efficiency reaches a maximum at fuel mass fraction about 30 percent and gasifier temperature in the range of 500°C to 700°C.     

Sulfur compounds in the fuel range fractions from different crude oils

A gas chromatograph coupled with sulfur chemiluminscence detector (GC-SCD) has been used for the speciation of individual sulfur compounds in fractions of different crude oils. The crude oil fractions characterized were light naphtha (C5-90°C), heavy naphtha (90–140°C), kerosene (140–240°C), and gas oil (240–370°C) fractions obtained from true boiling point distillation process. Low boiling fractions (up to 140°C) were analyzed by existing ASTM D5623 (American Society for Testing and Materials, 2009a) method for sulfur compound speciation. As there is no standard method for the distribution of sulfur compounds in high boiling samples (up to 370°C), therefore, a methodology has been developed for the diesel range samples. The identification of individual sulfur compounds were carried out by using reference sulfur compounds. The results show that type of sulfur compounds depends upon the boiling range of the fraction and source of crude oil. The major changes in the sulfur compounds profiles of different fractions are discussed. The results of this study can be used to predict the suitability of crude oil for the production of Euro-IV and V gasoline and diesel fuels.     

KINETICS OF HYDRODESULFURIZATION OF HEAVY GAS OIL DERIVED FROM OIL-SANDS BITUMEN

ABSTRACT

With gradual shortage in the supply of crude oil, the importance of producing synthetic crude oil from oil sands and shale oil is increasing day by day. In the present paper, the effects of various process variables such as temperature, liquid hourly space velocity and hydrogen/heavy gas oil volumetric ratio on the removal of sulfur compounds from oil sands derived heavy gas oil has been studied. The experiments have been carried out in a micro scale trickle bed reactor over a commercial Ni–Mo catalyst. The temperature, liquid hourly space velocity and hydrogen/heavy gas oil volumetric ratio have been varied from 365 to 415°C, 0.5 to 1.9 h^?1 and 400 to 1000 ml, respectively. Under optimum reaction conditions over 96% conversion of sulfur compounds was achieved. The kinetics of the rate of sulfur removal from the oil sands derived heavy gas oil has also been discussed in this article.     

加氢裂化反应工艺参数对喷气燃料馏分收率和性质的影响规律研究

为通过调整加氢裂化装置反应条件来控制喷气馏分燃料收率和质量,以中间基蜡油为原料在双剂串联一次通过流程下考察了裂化反应温度、氢分压、体积空速和氢油比对喷气燃料馏分收率和性质的影响。结果表明：不同反应条件下蜡油原料中大于350℃馏分的转化率影响喷气燃料馏分收率,蜡油原料中大于350℃馏分转化率越高,喷气燃料馏分收率越高;不同氢分压下,喷气燃料馏分的芳烃加氢饱和程度影响其烟点,其他反应条件参数对烟点的影响均和蜡油原料的转化深度相关。     

Performance-focused Catalyst Design to Meet Diesel Quality Improvements—Part II

Abstract

In this work, we present an experimental evaluation concerning the catalytic hydrocracking of gas oil (GO) feedstock. The study was carried out using five types of supported NiMo-based catalysts (100A, 100AP, 100AB, 100H-DY, and 30H-DY). Screening tests of the performance of these sulfided catalysts were carried out in a high-pressure batch autoclave at temperatures of 350°C–425°C, reaction time of 1–3 hr, catalyst/feed ratios of 5–10%, and initial hydrogen pressure of 6.0 MPa. This study clearly shows that the incorporation of H-DY zolite into aluminum borate (AB) matrix led to a greatly improved hydrocracking catalyst for production of lighter products, in addition to depressing the pour point of the diesel fuel product. In all experiments, the yield of gasoline and gaseous products increased dramatically by increasing the severity of the process variables. A high-pressure test unit was used to study the effect of different process variables as pressure (3.0–6.0 MPa), liquid hourly space velocity (1.5–3 hr^?1), hydrogen/ GO volumetric ratio (400 vol./vol.), and temperatures of 375°C, on the GO conversion to various products using 30H-DY catalyst, and to correlate the impact of process conditions on the yield and quality of diesel fuel and gasoline products to optimize the process     

The Effects of Multi-component Thermal Fluids on the Viscosity of Offshore Heavy Oil

Multi-component thermal fluids stimulation is a feasible way to recover offshore heavy oil reservoir. As a new technology, its mechanism of enhanced oil recovery should be understood through systematic simulation experiments and quantitative analysis. Laboratory experiments were carried out to investigate the effects of temperature, natural gas, and various gases (N₂, CO₂, or N₂+CO₂) on the viscosity of heavy oil from Nanbao block of Bohai offshore oilfield. The results show that in the range of 56°C (reservoir temperature) to 120°C, natural gas saturated and degassed oils are all very sensitive to temperature, and the viscosity is reduced by more than 90% when heated to 120°C; under lower temperature condition, injection of 5MPa N₂, N₂+CO₂, or CO₂ can significantly reduce the viscosity of natural gas saturated heavy oil, with a viscosity reduction ratio of about 20%, 50%, and 80%, respectively, at 56°C. Therefore, heavy oil production by viscosity reduction can be achieved by raising temperature or through gas injection. Taking into account the equipment, heat loss, and cost of steam injection, the technology of moderate heating, auxiliary gas injection is very promising for the recovery of Nanbao heavy oil.