Deasphalting of crude oils using supercritical fluids

A crude oil has four main SARA constituents: saturates, aromatics, resins, and asphaltenes. The asphaltenes in crude oil are the most complex and heavy organic compounds. The asphaltenes contain highly polar substituents and are insoluble in an excess of n-heptane (or n-pentane). The classic definition of asphaltenes is based on the solution properties of petroleum residuum in various solvents. Asphaltenes are a solubility range that is soluble in light aromatics such as benzene and toluene, but is insoluble in lighter paraffins. The particular paraffins, such as n-pentane and n-heptane, are used to precipitate asphaltenes from crude oil. The effects of four different solvents (water, carbon dioxide, propane, and ethanol) on the deasphalting process under the supercritical conditions were reviewed. Supercritical water is an excellent solvent for removing of high molecular weight organic compounds such as asphaltenes from crude oils under the supercritical conditions.     

Gasoline- and diesel-like products from heavy oils via catalytic pyrolysis

Heavy oil is less expensive than light crude oil, but heavy oil is more expensive to obtain light oil products. Conventional light crude oil resources are decreasing, therefore heavy oil resources will be needed more in the future. There are huge differences from field to field for heavy oil deposits. In terms of final productive use, heavy oil is considered as an unconventional resource. Heavy oil upgrading depends on four important factors: catalyst selection, heavy oil classification, process design, and production economics. Heavy and extra-heavy oils are unconventional reservoirs of oil. Globally, 21.3% of total oil reserves are heavy oil. Heavy oil is composed of long chain organic molecules called heavy hydrocarbons. The thermal degradation of the heavy hydrocarbons in heavy oil generates liquid and gaseous products. All kinds of heavy oils contain asphaltenes, and therefore are considered to be very dense material. The most similar technologies for upgrading of heavy oils are pyrolysis and catalytic pyrolysis, thermal and catalytic cracking, and hydrocracking. The amount of liquid products obtained from pyrolysis of heavy oil was dependent on the temperature and the catalyst. Pyrolytic oil contains highly valuable light hydrocarbons as gasoline and diesel components range. The constant increase in the use of crude oils has raised prices of the most common commercial conventional products and consequently seeking for new alternative petroleum resources, like some unconventional oil resources, becomes an interesting issue. The mass contents of gasoline, diesel, and heavy oil in the crude oil are 44.6%, 38.3%, and 17.1%, respectively. The gasoline yield from the heavy oil catalytic (Na₂CO₃) pyrolysis is higher than the diesel efficiency for all conditions. The yield of gasoline products increases with increasing pyrolysis temperature (from 230°C to 350°C) and percentage of catalyst (from 5% to 10%). The yields of gasoline-like product are from 21.5% to 39.1% in 5% catalytic run and from 32.5% to 42.5% in 10% catalytic run. The yields of diesel-like product are from 9.3% to 29.8% in 5% catalytic run and from 15.5% to 33.7% in 10% catalytic run.     

稠油和油砂中沥青质等重质组分的轻度氧化降解

稠油和油砂是广泛存在的重要资源，沥青质等重质组分的存在是难以直接开发利用这些资源的关键因素。移动稠油和油砂中重质组分的轻度氧化降解问题进行了实验研究，氧化降解体系为NaIO4/NaH2PO4和30%H2O2/CH3COOH。实验结果，稠油中沥青质的降解率达到45%以上，并且沥青质降解后主要向胶质组分转化，这非常有利于增加稠油体系的稳定性；油砂经降解处理后，与空白实验相比，油砂中的重质组分得到化学降解改造，可抽提的总有机质含量明显提高。氧化降解处理可以改善稠油、油砂等重质油的理化性质，可望在稠油油藏的开发利用方面得到应用。     

Deposition and flocculation of asphaltenes from crude oils

A crude oil has four main constituents: saturates, aromatics, resins, and asphaltenes. The asphaltenes in crude oil are the most complex and heavy organic compounds. The classic definition of asphaltenes is based on the solution properties of petroleum residuum in various solvents. Asphaltenes are a solubility range that is soluble in light aromatics such as benzene and toluene, but are insoluble in lighter paraffins. The particular paraffins, such as n-pentane and n-heptane, are used to precipitate asphaltenes from crude oil. Deposition of asphaltenes in petroleum crude and heavy oil can cause a number of severe problems. The precipitation of asphaltene aggregates can cause such severe problems as reservoir plugging and wettability reversal. Asphaltenes can precipitate on metal surface. Cleaning the precipitation site as well as possible appears to slow reprecipitation. To prevent deposition inside the reservoir, it is necessary to estimate the amount of deposition due to various factors. The processes can be changed to minimize the asphaltene flocculation, and chemical applications can be used effectively to control depositions when process changes are not cost effective. Asphaltene flocculation can be controlled through better knowledge of the mechanisms that cause its flocculation in the first place. The processes can be controlled to minimize the asphaltene flocculation, and chemical applications can be used effectively to control depositions when process changes are not cost effective.     

重质船用燃料油黏度预测模型研究

研究了现有黏度预测模型应用于重质船用燃料油黏度预测的可行性,筛选几种常见的黏度物理模型,进行试验数据对比和最优模型选取,基于重质船用燃料油数据库对Cragoe模型进行修正,并结合掺稀降黏试验数据分析混合机制对预测模型相对误差的影响。结果表明,针对目前市场上常用的重质船用燃料油调合组分,采用Cragoe黏度模型进行预测误差较小。这是由于Cragoe黏度模型的预测不受组分油黏度比的限制,在重质船用燃料油中的适用性最好。采用所提出的修正模型,可进一步降低对重质船用燃料油黏度预测的误差。分析多组分调合的结果显示,若组分中的黏度呈梯度分布时可降低预测误差。另外,渣油与稀组分油（简称稀油）调合时,沥青质的络合效应在一定程度上会影响模型的预测准确性。     

Concentrations of vanadium and nickel and their ratio in heavy oil asphaltenes

Trends in the vanadium and nickel concentrations in asphaltenes of heavy oils from different oilfields, in which the total content of these metals vary from 0.0049 to 0.1795 wt %, have been studied. It has been shown that as the vanadium and nickel content in heavy oils increases, vanadium concentrates faster than nickel in asphaltenes. In heavy oils, asphaltenes contain approximately 40–90% of total vanadium and 25–75% of total nickel. The summed concentration of vanadium and nickel in heavy oil asphaltenes can reach 1 wt %.     

后危机时代世界炼油工业面临的挑战和机遇

介绍了2008年国际金融危机对世界炼油工业带来的各种影响,分析了在后危机时代世界炼油工业面临的各种机遇与挑战。挑战：（1）炼油能力过剩增加;（2）国际油价走高;（3）轻重原油价差收窄;（4）汽柴油价格颠倒;（5）炼油工业要为提高汽车燃油效率,增加生物燃料用量和减排CO2付出沉重代价;（6）炼油工程建设项目投资难以大幅度减少。机遇：（1）石油基运输燃料将继续主导世界运输燃料市场,炼油厂仍将是汽油和柴油的主要来源地;（2）轻重原油价差会重新拉大;（3）升级换代炼油技术不断出现,重质劣质渣油深度转化技术取得突破性进展;（4）亚太地区将持续引领全球炼油能力的增长。     

The Mild Oxidative Degradation of the Heavy Constituents in Viscous Crude Oils/Oil Sands and Its Prospect in Oil Recovery

Viscous crude oils and oil sands are important energy resources, but it is difficult to exploit them due to the dominated heavy constituents such as asphaltenes. In this work, the mild oxidative degradation of the heavy constituents (oxidized by NaIO₄/NaH₂PO₄ and 30% H₂O₂/CH₃COOH) has been carried out. In the viscous oils, more than 45% asphaltenes has been degraded, and the asphaltenes are mainly chemically changed into the resin fractions, which is favorable to the stability of viscous crude oils. After the degradation, the total amount of extractable organic compounds from oil sands has been markedly increased than that of the blank experiment. The experimental results indicate that the mild oxidative degradation of asphaltenes can improve the physicochemical properties of the viscous oils and oil sands, which is particularly in favor of the exploitation of these energy resources.     

石油重油和煤混合加氢对重油性质的影响

在间歇式小型高压釜中进行了不同石油重油和煤混合加氢试验。结果表明，石油重油和煤混合加氢处理后，其轻质馏份增加，初馏点降低，处理后油的饱和烃含量和分子量均随加氢反应温度升高而降低，而芳烃含量则随加氢反应温度升高而增加。试验发现处理后重油中Ｆｅ、Ｎｉ、Ｃｕ等重金属和Ｓ含量都有不同程度降低，尤其是大庆重油与煤混合加氢后Ａｓ含量显著降低，其脱除率有的高达９０％以上     

Pyrolytic Distillation of No. 4 Fuel Oil

Fuel oils (numbers 1–6) are fractions of crude oil. The boiling point and carbon chain length of the fuel increases with fuel oil number. Viscosity increases with the number, and is needed to flow the heated heavy oil. No. 4 fuel oils are used as burner fuel for domestic and industrial heating and have to raise steam for power generation and marine propulsion. Recycling and rerefining are application processes for the treatment of petroleum-based heavy products by converting into reusable light products such as gasoline and No. 2 diesel fuel. Possible pyrolysis and cracking processes are appropriate. The purpose of this study is performed to obtain light products, especially gasoline and No. 2 diesel fuel from No. 4 fuel oil by the method of pyrolytic distillation. Sodium carbonate (Na₂CO₃) was used in pyrolysis as catalyst and the purified oil samples were blended separately with catalysts having a mass basis of 5% and 10%. If the objective is to maximize the yield of distillate producing from No. 4 fuel oil, a low temperature and a high heating rate process would be required. The yield of gasoline-like fuel was 10.6% in the noncatalytic conversion, while 13.3% was obtained in the catalytic conversion. The yield of No. 2 diesel-like fuel was 23.3% in the noncatalytic conversion, while of 32.6% was obtained in the catalytic conversion. The yield of No. 2 diesel-like obtained from the catalytic conversion was higher 39.9% than that of the noncatalytic conversion.     

TWO-DIMENSIONAL SOLUBILITY PARAMETER MAPPING OF HEAVY OILS

The solubility and insolubility of heavy oils and their fractions in dilute mixtures with various solvents were used to characterize heavy oil interactions. A two-dimensional solubility parameter, developed for the selection of solvents for organic polymers, was found to group all the solvents for each heavy oil fraction in polygon areas when the complexing solubility parameter component was plotted against the field force solubility parameter component. All fractions of Cold Lake vacuum residua, except for the saturate fraction, form concentric solubility areas. Therefore, in going in the direction of decreasing aromaticity from coke to asphaltenes to resins to aromatics, all solvents for the previous fraction in the series are also solvents for all subsequent fractions in the series. As a result, asphaltenes can be precipitated, but not extracted, from heavy oils. This is attributed to the interaction among polynuclear aromatics being the dominate interaction in petroleum that causes insolubility in hydrocarbon liquids. However, the paraffinic chains on the same petroleum molecules limit their solubility in highly complexing liquids. In contrast, even vacuum gas oils from the Exxon Donor Solvent coal liquefaction process are insoluble in aromatic liquids but soluble in moderately complexing liquids because of hydrogen bonding, resulting from oxygen functionality. Hydrotreating of these coal derived vacuum. gas oils reduces their oxygen functionality and increases their solubility areas so that they become compatible with petroleum liquids.     

TWO-DIMENSIONAL SOLUBILITY PARAMETER MAPPING OF HEAVY OILS

ABSTRACT

The solubility and insolubility of heavy oils and their fractions in dilute mixtures with various solvents were used to characterize heavy oil interactions. A two-dimensional solubility parameter, developed for the selection of solvents for organic polymers, was found to group all the solvents for each heavy oil fraction in polygon areas when the complexing solubility parameter component was plotted against the field force solubility parameter component. All fractions of Cold Lake vacuum residua, except for the saturate fraction, form concentric solubility areas. Therefore, in going in the direction of decreasing aromaticity from coke to asphaltenes to resins to aromatics, all solvents for the previous fraction in the series are also solvents for all subsequent fractions in the series. As a result, asphaltenes can be precipitated, but not extracted, from heavy oils. This is attributed to the interaction among polynuclear aromatics being the dominate interaction in petroleum that causes insolubility in hydrocarbon liquids. However, the paraffinic chains on the same petroleum molecules limit their solubility in highly complexing liquids. In contrast, even vacuum gas oils from the Exxon Donor Solvent coal liquefaction process are insoluble in aromatic liquids but soluble in moderately complexing liquids because of hydrogen bonding, resulting from oxygen functionality. Hydrotreating of these coal derived vacuum. gas oils reduces their oxygen functionality and increases their solubility areas so that they become compatible with petroleum liquids.     

松辽盆地北部西斜坡区稠油成因与油源关系

松辽盆地北部西斜坡区分布的稠油资源是油气勘探的潜在领域。油藏流体地球化学分析表明，该地区稠油形成主要与厌氧细菌的生物降解作用有关。稠油的高温气相色谱分析，可以把稠油划分为2种成因类型、5个亚类。生物降解成因类型包括严重降解稠油、中等降解稠油和轻度降解稠油3个亚类；混合成因类型包括降解原油与原油蒸馏轻烃混合形成的稠油和降解原油与未降解原油混合形成的稠油2个亚类。生物标志化合物参数揭示的油岩关系表明，稠油来自斜坡东部的齐家—古龙凹陷的成熟烃源岩和该地区的未熟—低熟烃源岩，优越的油源条件为该地区稠油勘探展示了广阔前景。     

The Mild Oxidative Degradation of the Heavy Constituents in Viscous Crude Oils/Oil Sands and Its Prospect in Oil Recovery

Abstract

Viscous crude oils and oil sands are important energy resources, but it is difficult to exploit them due to the dominated heavy constituents such as asphaltenes. In this work, the mild oxidative degradation of the heavy constituents (oxidized by NaIO₄/NaH₂PO₄ and 30% H₂O₂/CH₃COOH) has been carried out. In the viscous oils, more than 45% asphaltenes has been degraded, and the asphaltenes are mainly chemically changed into the resin fractions, which is favorable to the stability of viscous crude oils. After the degradation, the total amount of extractable organic compounds from oil sands has been markedly increased than that of the blank experiment. The experimental results indicate that the mild oxidative degradation of asphaltenes can improve the physicochemical properties of the viscous oils and oil sands, which is particularly in favor of the exploitation of these energy resources.     

沥青质对稠油黏度的影响

选用新疆地区的6种高黏稠油为主要研究对象,测定各稠油的性质并配制不同沥青质含量的同源调合稠油、异源调合稠油,利用黏度法考察沥青质含量对稠油黏度的影响。结果表明：无论是同源调合稠油还是异源调合稠油,随着沥青质添加量的增加,稠油黏度均呈增大的趋势,且在沥青质添加量达到一定值时黏度出现突变;相同温度、相同沥青质含量下,四氢呋喃处理过的稠油黏度比甲苯处理过的稠油黏度要大,且增加幅度较甲苯处理过的要大。     

Behavior and Role of Asphaltenes in a Two-stage Fixed Bed Hydrotreating Process

Residue upgrading processes are very important for the production of distillates and low sulfur fuel oils. Among those, fixed bed technologies are very efficient for deep desulfurization of petroleum residue heavy oils, even for highly asphaltenic feeds. This work analyzes the effects of the operating conditions on the evolution of asphaltenes and on their inhibition effect during the hydrodesulfurization reactions. Residue hydrotreating experiments were performed on a pilot plant and asphaltene fractions were investigated using size exclusion chromatography (SEC), ¹³C nuclear magnetic resonance (NMR), liquid chromatography, and elemental analyses. Besides the overall decrease in asphaltenes yield, significant changes in the average structure of the asphaltenes were also observed.     

Prediction of Asphaltene Precipitation in Live and Tank Crude Oil Using Gaussian Process Regression

The study of asphaltene precipitation properties has been motivated by their propensity to aggregate, flocculate, precipitate, and adsorb onto interfaces. The tendency of asphaltenes to precipitation has posed great challenges for the petroleum industry. Since the nature of asphaltene solubility is yet unknown and several unmodeled dynamics are hidden in the original systems, the existing models may fail in prediction the asphaltene precipitation in crude oil systems. The authors developed some Gaussian process regression models to predict asphaltene precipitation in crude oil systems based on different subsets of properties and components of crude oil. Using feature selection techniques they found some subsets of properties of crude oil that are more predictive of asphaltene precipitation. Then they developed prediction models based on selected feature sets. Results of this research indicate that the proposed predictive models can successfully predict and model asphaltene precipitation in tank and live crude oils with good accuracy.     

基于多产化工品的重油原料烃类结构导向研究

石油炼制的化工转型及中间基原油供给比例持续增大的趋势均愈发明显。但中间基劣质渣油中硫、氮、重金属等杂原子含量高,稠环芳烃、胶质、沥青质等难裂化重组分多,对多产化工品途径带来挑战,需通过加氢等前处理工艺进行改质。基于重油分子水平组成、烃分子结构结合催化裂解反应化学研究,提出多产化工品的优势原料烃类组成结构为链烷烃、一环～四环环烷烃及烷基苯,需要渣油加氢与催化裂解两个单元很好地耦合。中间基渣油加氢改质的方向为稠环芳烃超深度加氢饱和并适度裂化。从分子水平表征中间基渣油加氢前后烃组成结构的变化显示,中国石化石油化工科学研究院以烃类结构为导向,采用加氢过程实现了多环芳烃、噻吩型含硫芳烃、胶质、沥青质的深度加氢饱和,定向转化为链烷烃和环烷烃尤其是一环～三环环烷烃等可多产化工品的优势烃类结构,进而与高选择性催化裂解技术耦合可实现劣质中间基渣油多产低碳烯烃和BTX（苯、甲苯、二甲苯）等化工品的目标。     

Behavior and Role of Asphaltenes in a Two-stage Fixed Bed Hydrotreating Process

Abstract

Residue upgrading processes are very important for the production of distillates and low sulfur fuel oils. Among those, fixed bed technologies are very efficient for deep desulfurization of petroleum residue heavy oils, even for highly asphaltenic feeds. This work analyzes the effects of the operating conditions on the evolution of asphaltenes and on their inhibition effect during the hydrodesulfurization reactions. Residue hydrotreating experiments were performed on a pilot plant and asphaltene fractions were investigated using size exclusion chromatography (SEC), ¹³C nuclear magnetic resonance (NMR), liquid chromatography, and elemental analyses. Besides the overall decrease in asphaltenes yield, significant changes in the average structure of the asphaltenes were also observed.     

Removing of resins from crude oils

Crude oil contains four chemical group classes, namely saturates, aromatics, resins, and asphaltenes (SARA fractions). Resins fraction of crude oil comprises polar molecules often containing heteroatoms such as nitrogen, oxygen, or sulfur. Resin is a heavier fraction than aromatics and saturates. Resins are composed of fused aromatic rings with branched paraffin and polar compounds. The resin fraction is soluble in light alkanes such as pentane and heptane, but insoluble in liquid propane. The resins are adsorbed on a solid such as alumina, clay, or silica, and subsequently recovered by use of a more polar solvent and the oils (aromatics and saturates) remain in solution. The resins often coprecipitate with the asphaltenes in controlled propane deasphalting procedures. The composition of the resins can vary considerably and is dependent on the kind of precipitating liquid and on the temperature of the liquid system. The resins are adsorbed on a solid such as alumina, clay, or silica, and subsequently recovered by use of a more polar solvent and the oils (aromatics and saturates) remain in solution.