Desulfurization of FCC Gasoline by Solvent Extraction and Photooxidation

A deep desulfurization process for FCC light gasoline has been investigated. The process is comprised of liquid-liquid extraction with acetonitrile, and photooxidation with ultraviolet light from a high-pressure mercury lamp. After the extraction the sulfur-containing compounds transfer from the oil to the solvent and then the solvent containing these sulfur compounds was photo-irradiated with ultraviolet light from a high pressure mercury lamp 300 W and with λ 200-300 nm, using strengthen electronic stirrer during the irradiation .The oil from the solvent was recovered with water. An azeotropic mixture (containing 86% acetonitrile and 14% water) was recovered successfully with one distillation column, and can reuse. The total sulfur content in this gasoline decreased from 309 to 68 ppm following 8 h of photo-irradiation .The total yield of the oil vary between 90-96%. The main sulfur compounds of this gasoline are alkyl substituted thiophenes.     

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

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.     

Advantages of Mild Hydrocracking FCC Feed—A Pilot Plant Study

In view of increasingly stringent environmental regulations with respect to SOx and particulate emissions, the allowable sulphur and nitrogen levels in diesel and gasoline are reducing all over the world. Fluid catalytic cracking (FCC) unit is a major source of fuels produced from a refinery. Any attempt to reduce sulphur and nitrogen content of distillates produced from FCC unit will greatly improve the quality of fuels. In the present work, pilot plant studies were conducted to evaluate the options of hydrotreating and mild hydrocracking (MHC) of FCC feedstock. Experiments were conducted on commercially available catalyst samples using high nitrogenous vacuum gas oil (VGO) as feedstock. MAT experiments were also conducted to compare the conversions and yields of untreated, hydrotreated, and MHC VGO at constant operating conditions. Pilot plant data showed that MHC of VGO would produce additional fuels to the extent of 15% under moderate operating conditions besides improving the quality of FCC feedstock. The mild hydrocracked VGO as feed was found to increase FCC conversion by 2 wt%, increase fuels by 2.5 wt%, reduce residue by 2.8 wt% compared to untreated vacuum gas oil.     

RECOVERY OF ORGANIC MATTER FROM GREEN RIVER OIL SHALE AT TEMPERATURES OF 400°C AND BELOW

Experiments to recover organic matter from Green River oil shale in high yields at temperatures of 400^°C and below are described. Three different recovery procedures are discussed: 1) experiments wherein liquid organic materials were extracted at atmospheric pressure and temperatures below 75^°C by solvents of different strengths, 2) autoclave experiments where liquid organics were recovered by heating the shale with a variety of solvents at temperatures between 300 and 400^°C and pressures between 5 and 32 MPa, and 3) an autoclave experiment where liquid organics were recovered by heating shale in an argon atmosphere for 1 hour at 400^°C. The liquid organic materials recovered in these experiments represent from four to 90 weight percent of the total organic material in the shale. The liquid organic materials have an average molecular weight of between 500 and 600 amu as compared to a typical shale oil that has an average molecular weight of 300 to 350 amu. Elemental analyses show that the liquid organic materials contain high percentages of hydrogen and nitrogen, as does shale oil. Moreover, the liquid organic materials also contain much larger concentrations of oxygen-containing compounds than shale oil. The experimental results suggest the possibility of developing a new process for recovering both organic and inorganic material from Green River shale.     

Abrasive Water Jet Perforation—An Alternative Approach to Enhance Oil Production

This article investigates the mechanisms, the results of laboratory experiments, and the results of field tests on the abrasive water jet (AWJ) perforation for enhancing oil production. The mechanism investigation showed that the AWJ perforation is a two-stage process, the ductile casing erosion stage and the brittle rock penetration stage, and each stage follows different failure mechanisms. The laboratory AWJ-parameter experiments were conducted on pressure, flow rate, abrasive material, abrasive granule size, abrasive flow rate, ambient pressure, rock material, and exposure time. The field tests of 10 oil wells (11 runs) illustrated that the AWJ perforation depth could reach about 0.78 m with pump pressure of 45-60 MPa at different formations, while the location error was less than 0.1 m. The oil production rate comparison, before and after implement, showed the AWJ perforation technology can effectively and prominently enhance oil production.     

Thermal Hydrocracking Kinetics of Chinese Gudao Vacuum Residue

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.     

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.     

DEEP DESULPHURISATION OF A DIESEL BLEND IN A PILOT PLANT TRICKLE BED REACTOR

A pilot plant investigation was conducted to study the influence of hydrotreating conditions on conversion and characteristics of diesel blend and to determine the severity of operating conditions required to meet the proposed product specifications for diesel fuel in India. A typical diesel blend derived from various refinery streams with sulphur content of 2·06 wt% was hydrodesulphurised over a commercial NiO-MoO₃/Al₂O₃ catalyst in a pilot plant trickle bed reactor. The experiments were conducted at 300-370°C, 30-50 kg/cm², 2·0 3·0 hr^-1 liquid hourly space velocity and constant H₂/oil ratio of 185 m³/m³. The data showed that the diesel blend could be hydrotreated to meet revised product specifications of 0·25 wt% sulphur, 46 cetane number by increasing the severity of operation. The cetane number and aromatic saturation were limited by thermodynamic equilibrium at temperatures above 360°C. The influence of temperature was found to be more pronounced than that of pressure in the range of operating conditions studied.     

Molecular Weight Measurement of UG8 Asphaltene Using APCI Mass Spectroscopy

Asphaltene molecular weight has been a controversial issue in the past several decades and continues on nowadays. From industrial application point of view, asphaltene molecular weight is important for setting up a heavy oil refining strategy so that the process is efficient and economically viable. If the measured average molecular weight of asphaltene is high and is the true molecular weight, then substantial amount of energy will be needed, in order to break the molecule into light products during refining process. This is likely not an economical option. On the other, if the measured high molecular weight is due to self-association and the true molecular weight is low (e.g., less than 1500 Da), it will be energetically attractive to refiners to develop heavy oil cracking technology. Vapor pressure osmometry (VPO) has been routinely used for measuring molecular weight. However, it measures the apparent molecular weight and is likely not the true molecular weight. In order to unambiguously measure the molecular weight, it is necessary to develop a convincing technology and a reliable experimental procedure that allows one to measure the molecular weight accurately and consistently. We chose the Atmospheric Pressure Chemical Ionization (APCI) technique and Atmospheric Pressure Photo Ionization (APPI) to measure UG8 asphaltene. Both APCI and APPI have mild ionization processes and have been applied to many unstable drug compounds such as proteins and peptides with reliable outcomes. In addition, we measured the sample on two APPI instruments to compare the results. We also demonstrated how one can choose wrong set of operating parameters and lead to erroneous results. The relevant parameters for APCI and APPI are temperature, voltage, and sample concentration. We chose 0.01 mg/mL as the concentration, much below any known critical aggregation concentration. As for temperature and ionization voltage, we varied systematically varied (T = 300-600°C; V = 30-150 V) in order to demonstrate the consistency of the methods and how one can easily make mistake. Through these measurements, an average molecular weight of 400 to 900 Da was obtained for UG8 asphaltene.     

CATALYST EFFECTIVENESS FACTORS UNDER GAS-TO-LIQUID MASS TRANSFER LIMITING REGIME IN LIQUID PHASE METHANOL SYNTHESIS PROCESS

The effectiveness factors of methanol synthesis catalyst were experimentally measured under condition of gas-to-liquid mass transfer limiting regime in the liquid phase methanol synthesis process, where the synthesis catalyst is slurried in an inert liquid phase. The experimental measurements of effectiveness factors were based on an intrinsic methanol synthesis rate per unit mass of catalyst (gmol/kg cat.h) which is not limited by external mass transfer. The experiments were carried out under well-defined conditions of temperature, pressure, syngas feed flow rate, and impeller speed. The experiments were carried out in a 1-L stirred autoclave. The catalyst slurry ratios were varied from 10 g in 550 mL of Witco-40 oil (corresponding to a slurry ratio of 2.2%) to 150 g in 550 mLof Witco-40 oil (corresponding to a slurry ratio of 25.1%). The experimental measurements have been summarized in one single plot as generalized catalyst effectiveness factor as a function of catalyst slurry ratio. The results of this study are extremely significant and practical in their applicability because the data were obtained using commercial methanol catalysts under actual commercial operating conditions of liquid phase methanol synthesis process.     

丙烷制冷系统改造运行效果及水露点分析

苏里格气田天然气中含水和凝析油,基本不合硫等,苏里格第一天然气处理厂通过丙烷制冷低温分离工艺进行脱水脱烃,使露点达到国家二级气质标准要求,直接进入管道输送。苏里格气田在2002年先导性开发试验中,采用高压节流降温低温分离工艺取得了良好的效果。由于苏里格气田属于低压低产气田,单井压力下降快,2003年在原流程上增加了氨制冷设备,采用冷却法实现低温分离。现处理厂首先采用管壳式换热器利用净化后的产品气对原料气进行换热,再采用丙烷制冷方法来进一步进行降温来实现低温分离。现对丙烷制冷设备的现场运行情况进行分析,并针对运行中出现的问题提出整改的措施来保证以后生产的平稳运行。     

A Comprehensive Evaluation of High Viscous Crude Oil from Shuguang No. 1 Zone of Liaohe Oil Field

The high viscous crude oil from Shuguang No. 1 zone of Liaohe oil field has the characteristics of high density (ρ₂₀ = 0.9977 g cm^-3), great viscosity (ν₁₀₀ = 1223.9 mm² s^-1) and high pour point (48°C), which are similar to those of the residue distillation of general crude oils. It contains no gasoline distillation and the diesel oil fraction yield is just 7.19%. It is often used as fuels after emulsification. But this oil is so vicious that it cannot be atomized uniformly and burned fully. In order to make full use of it, this kind of high viscous crude oil has been evaluated comprehensively and the properties of its various distillations are analyzed respectively. The results indicate that this crude oil contains less wax, but more resins and asphaltene, which belongs to low-sulfur naphthene-base crude oils and it is the suitable material to produce high-quality paving asphalt. Based on its characteristics, the optimum processing scheme is put forward and the high-quality paving asphalt is produced by using the distillation higher than 350°C.     

凝析油充注对油藏沥青质分子结构的影响

用原油沥青质的地球化学研究结果分析油气藏形成条件，前提是油藏沥青质分子结构不因后期天然气或凝析油的再次充注而变化。在塔里木盆地轮南1井产出原油中加入不同体积的石油醚，模拟后期凝析油充注早期油藏的过程，测定不同沉淀条件下原油的沥青质沉淀量变化，并用瞬间热解-色谱-质谱的方法研究沥青质的分子结构。实验结果，原油沥青质随低分子烃类注入量的变化发生沉淀和再溶解，但沉淀出的沥青质分子结构相同。据此认为，低分子烃类加入原油体系不会改变沥青质的分子结构特征，沥青质热解产物能够反映原油的母质结构特征，可以根据该特征进行油／源、油／油对比或探讨混源油的母源类型。图5参19     

A NOVEL TECHNIQUE OF ASPHALTENE DEPOSITION TREATMENT USING ULTRASONIC IRRADIATION

The need for better understanding of asphaltene behavior in the crude oil and treatment techniques of its deposition in porous medium has been recognized but still requires extensive research and experimental activities. The ambitious goals of this study are to investigate: (1) influences of using ultrasonic irradiation on asphaltene behavior in the UAE crude oil, with consideration of solvent and temperature effects; and (2) influences of ultrasonic irradiation characteristics such as frequency and time interval on damaged oil permeability (due to asphaltene deposition) of carbonate reservoir rocks. To achieve the above-mentioned goals, three groups of experiments using ultrasonic irradiation were carried out. In the first group, 18 identical crude oil samples of 2.47 wt% initial asphaltene content were subjected to different time intervals of ultrasonic irradiation of 0, 5, 10, 15, 25 and 30 min and under different temperatures of 25, 40 and 60°C, respectively. Oil viscosity was measured and microscopic images of the centrifugated oil samples of asphaltene clusters were obtained. In the second set of experiments, 12 identical crude oil samples with different toluene concentrations of 5, 10, and 15 vol% were subjected to four different durations of ultrasonic irradiation and under different temperatures. In the third group, seven actual carbonate core samples of damaged oil permeability due to the injection of 60 pore volumes of asphaltic crude oil were subjected to different ultrasonic time interval of 5, 10, 15, 20, and 25 min and frequencies of 10, 15 and 20 kHz, respectively. Both the oil permeability of these samples was measured and the scanning electron microscope (SEM) images were carried out before and after the ultrasonic irradiation process. The results showed that subjection of the UAE crude oil to ultrasonic irradiation decreases the size of asphaltene clusters. Consequently, this effect reduces asphaltene tendency to precipitate at 10 min or more time interval of ultrasonic irradiation. In addition, similar results were obtained with solvent effect, but with more reduction in oil viscosity. The results also indicated that the increase of ultrasonic time interval and/or frequency drastically improve(s) damaged oil permeability.     

Sulfur Reduction in FCC Gasoline with a Commercial Additive: A Microactivity Study

The use of advanced FCC catalysts and additives to reduce sulfur in gasoline remains the preferred option to refiners because of its economic and operation incentives. The performance of a commercial sulfur-reducing additive blended with a fresh RE-USY catalyst was assessed in a microactivity (MAT) unit using Arabian Light vacuum gas oil (VGO). The additive was evaluated at different concentrations (0-15 wt%) in terms of sulfur reduction capability and its effect on product yield structure, mainly gasoline. At 5 wt% additive, the results showed a 14 wt% reduction in total gasoline sulfur with minor effect on catalytic activity and product selectivity. Minimal reduction capability was observed towards benzothiophene (BT), which is difficult to crack and remove under cracking conditions. Upon increasing additive concentration to 10 wt%, total sulfur was reduced to 21 wt% compared to 27 wt% reduction at 15 wt% additive. At this additive concentration, aromatic sulfur compounds mainly C4-thiophenes and a portion of BT were cracked to tetrahydrothiophene, or thiophene, which were subsequently cracked to H₂S and light gases.     

EWAN C-2/C-3 POLYMER FLOOD: PERFORMANCE PREDICTIONS

This paper describes the study carried out to predict the performance of polymer flooding in Ewan C-2 and C-3 reservoir sands. The polymer flood predictions model employed is a three-dimensional, stratified, five-spot, two-phase (water and oil) model based on a polyacrylamide. Peak recoveries were found to exhibit remarkable sensitivity to operating parameters. At the base case conditions of 124.2 acres spacing, polymer adsorption of 15 lb/ac.ft, polymer concentration of 600 ppm and injection rate of 1000 RB/D, it was established that oil recovery up to 45% OOIP corresponding to oil/polymer ratio of 15STB/Ib are attainable in both Ewan C-2 and C-3 reservoirs, with the C-3 exhibiting greater potential.     

Desulfurization of FCC Gasoline by Solvent Extraction and Photooxidation

Abstract

A deep desulfurization process for FCC light gasoline has been investigated. The process is comprised of liquid-liquid extraction with acetonitrile, and photooxidation with ultraviolet light from a high-pressure mercury lamp. After the extraction the sulfur-containing compounds transfer from the oil to the solvent and then the solvent containing these sulfur compounds was photo-irradiated with ultraviolet light from a high pressure mercury lamp 300 W and with λ 200–300 nm, using strengthen electronic stirrer during the irradiation .The oil from the solvent was recovered with water. An azeotropic mixture (containing 86% acetonitrile and 14% water) was recovered successfully with one distillation column, and can reuse. The total sulfur content in this gasoline decreased from 309 to 68 ppm following 8 h of photo-irradiation .The total yield of the oil vary between 90–96%. The main sulfur compounds of this gasoline are alkyl substituted thiophenes.     

TIRE-TREAD AND BITUMEN PARTICLE CONCENTRATIONS IN AEROSOL AND SOIL SAMPLES

Tire and bitumen particle concentrations are determined in aerosol and soil samples. They each constitute about 5 wt-% of the total suspended particulate matter (TSP) in inner city air, collected with a Berner low pressure impactor, 5 m from a road. The particle size distribution shows that 92% of the mass of airborne particulate tire debris have aerodynamic diameters smaller than 1 µm. The mean aerodynamic diameter is about 1 µm for the bitumen particles. This size range enables the possibility for far range transport and inhalation by humans. Soil concentrations in the vicinity of a highway indicate an approximate exponential decrease with increasing distance from the road. Constant values are reached after about 5 m for the tire particles and 10 m for the bitumen particles. Concentrations in soil that has not been touched for at least 30 years show a decrease in tire concentration by a factor of 30 when moving from the top soil to a depth of 3 cm. The bitumen concentration is approximately constant to a depth of 10 cm.     

Comparisons Between Asphaltenes from the Dead and Live-Oil Samples of the Same Crude Oils

Asphaltenes precipitated from pressure-preserve bottomhole oil samples have been obtained for three oils at different pressures, using a bulk high-pressure filtration apparatus. The precipitates captured on the filter were recovered, the asphaltenes defined by the n-heptane insolubility were extracted and analyzed. These pressure-driven asphaltenes found on the filter were found to make up in the range between 50 and 100 ppm of the whole crude oil. Opening of the cell did not reveal asphaltenes retained due to wall adhesion. Size exclusion chromatography tests performed on both the live-oil-derived asphaltenes and the standard asphaltenes as precipitated by atmospheric titration on the same crude oil, revealed that the live-oil asphaltenes had apparent smaller hydrodynamic volume and narrower distributions than the standard asphaltenes for two oils. Further FTIR tests also showed large differences between standard asphaltenes and the asphaltenes obtained at high pressure filter. The latter appeared to contain more functional groups and be less saturated. Implication of these structural differences on precipitation modeling is discussed.     

COKE CHARACTERISTICS IN RELATION TO THE COLLOIDAL. MATTER OF PETROLEUM FOR THERMAL. PROCESSES

The purpose of this work is to research the characteristics of the production of coke in thermal and hydrothermal cracking from residual oils and their deasphalted oils Using ethyl acetate, because it allows the elimination of both resins and asphaltenes (colloidal matter) from the parent oil in only one step. This improves the deasphalted oil as coke precursors and basic nitrogen compounds present in the resin fraction are practically eliminated.

A 104 ml batch autoclave reactor with a cooling system was used for the thermal and hydrothermal cracking experiments. This reactor can withstand temperatures of up to 500^°C, pressures of 500 bar and a rocking velocity of 1 Hz. The influence of the temperature was investigated at 400, 425 and 450^°C and at 0, 20, 40, 80,