Rheology of Middle Distillate. I. Role of Composition

Abstract

The rheological behavior of middle distillate (250–375°C) fraction, obtained from the waxy Bombay-High Off-shore crude oil, and its five narrow sub-fractions of 25°C interval each, i.e., Fr 1 (250–275°C), Fr 2 (275–300°C), Fr 3 (300–325°C), Fr 4 (325–350°C), and Fr 5 (350–375°C), have been studied below their ASTM pour point temperatures. The rheograms (the shear stress vs. rate of shear) of the fraction and sub-fractions, at various temperatures below their pour points, are recorded on a Haake RV-12 Co-axial Rota Viscometer fitted with a NV sensor and a temperature programmer (PG-20) and attached with a programmed heating/cooling system. From these rheograms the flow parameters like plastic viscosity, apparent viscosity, and yield stress are obtained and their variations with temperature and shear rate have been studied in terms of compositions of the fraction/sub-fractions. These results might be useful in devising methodology for overcoming the wax separation phenomenon from middle distillates at low temperatures.     

Effect of some prepared superplasticizers on the rheological properties of oil well cement slurries

Three superplasticizers namely: cyclohexanone glyoxylic sulfanilate (CGS), acetone glyoxylic sulfanilate (AGS) and melamine glyoxylic sulfanilate (MGS) were prepared and characterized using FT-IR. The prepared admixtures were evaluated as additives for improving the rheological properties of oil well cement. The effect of temperature (25°, 45° and 65?°C) and admixture dose (0.25, 0.5, 0.75 and 1%) were determined on the apparent viscosity, plastic viscosity and yield stress. The results showed that the prepared superplasticizers, CGS, AGS and MGS decreased these parameters. The results concluded that the CGS, AGS and MGS admixtures act as retarders and dispersant for oil well cement. The three prepared admixtures exhibited high enhancement on the rheological properties which mean that it can use in oil cementing processes.     

The use of grass as an environmentally friendly additive in water-based drilling fluids

Excellent drilling fluid techniques are one of the significant guaranteed measures to insure safety,quality,efficiency,and speediness of drilling operations.Drilling Quids are generally discarded after the completion of drilling operations and become waste,which can have a large negative impact on the environment.Drilling materials and additives together with drill cuttings,oil.and water constitute waste drilling fluids,which ultimately are dumped onto soil,surface water,groundwater,and air.Environmental pollution is found to be a serious threat while drilling complex wells or high-temperature deep wells as these types of wells involve the use of oil-based drilling fluid systems and high-performance water-based drilling(luid systems.The preservation of the environment on a global level is now important as various organizations have set up initiatives to drive the usage of toxic chemicals as drilling fluid additives.This paper presents an approach where grass is introduced as a sustainable drilling fluid additive with no environmental problems.Simple waterbased drilling fluids were formulated using bentonite,powdered grass,and water to analyze the rheological and filtration characteristics of the new drilling fluid.A particle size distribution test was conducted to determine the particle size of the grass sample by the sieve analysis method.Experiments were conducted on grass samples of 300.90.and 35 μm to study the characteristics and behavior of the newly developed drilling fluid at room temperature.The results show that grass samples with varying particle sizes and concentrations may improve the viscosity,gel strength,and tiltration of the bentonite drilling fluid.These observations recommend the use of grass as a theological modifier,filtration control agent,and pH control agent to substitute toxic materials from drilling fluids.     

影响聚合物段塞流变性因素的研究

本文针对我国表面活性剂/聚合物驱油的实际,研究了石油磺酸盐(PS)、正丁醇(R_4OH)和矿化水对水解聚丙烯酰胺(HPAM)溶液流变性的影响。结果表明,PS对HPAM溶液流变性的影响与介质的矿化度有关:非矿化水介质中,PS对HPAM溶液性质的影响类似于无机盐,能降低HPAM溶液的表现粘度(η_α)和稠度系数(k);当系统中含有一定浓度矿化水时,PS却能升高系统的η_α和k值,降低流型指数(n),使系统的非牛顿性增强。在含有PS和矿化水的HPAM系统中加入R_4OH,系统的η_α和k值会有所增加。     

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为使各类流体能应用漏斗粘度计测量其流变参数,研究不同流体流动时间与流变参数的数学模型,是非常重要的问题。作者从塑性流体的本构方程出发,建立了非恒定静液柱作用下,该流体垂直下落的流动规律及其管嘴流动时间与流变参数及摩阻的相互关系,从而为计算漏斗粘度计中塑性流体的流变参数提供了理论依据。文章同样采用幂律流体等比例下降的多点式测量方法及其相关的试验数据,较简便地求解出塑性粘度和动切力的具体数值。文章最后应用具体实例,进一步说明测量和计算动切力和塑性粘度的步骤和过程。     

基于分子矩阵的馏分油组成的分子建模

将MTHS分子矩阵(Molecular type homologous series matrix)应用于馏分油组成的分子建模,提出了表征馏分油的IMTHS(Improved MTHS matrix)分子矩阵,并建立了IMTHS分子矩阵中等价组分的性质关联方法,实现了基于分子尺度的馏分油的分子表征。实例研究表明,IMTHS分子矩阵是一种可行的预测石油馏分近似分子组成的方法。     

Stabilization Studies of Middle Distillate Fuels: Structural Composition of Insoluble by FTIR Spectroscopy

Abstract

For reducing the supply-demand gap of diesel fuel, blending of cracked stocks is essential with straight run products. This enhances the instability problem. This problem can be reduced using various stabilization procedures. In the present paper blends of cracked stocks light cycle oil (LCO) with straight run gas oil (SRGO) were stabilized by methanol extraction and hydrostabilization techniques. The insoluble from these fuels as such and their blends were stabilized and characterized using FTIR spectroscopy.     

Stabilization Studies of Middle Distillate Fuels: Structural Composition of Insoluble by FTIR Spectroscopy

For reducing the supply-demand gap of diesel fuel, blending of cracked stocks is essential with straight run products. This enhances the instability problem. This problem can be reduced using various stabilization procedures. In the present paper blends of cracked stocks light cycle oil (LCO) with straight run gas oil (SRGO) were stabilized by methanol extraction and hydrostabilization techniques. The insoluble from these fuels as such and their blends were stabilized and characterized using FTIR spectroscopy.     

The Effect of Weathering on the Rheology of an Atypical Waxy Crude Oil

Abstract

The Stoney Creek field, located outside Moncton, New Brunswick, Canada, has been challenged by production problems throughout its history. The oil is identified as paraffinic oil with high wax content (estimates between 19.5% to over 50% wax) but no wax deposits have been found throughout the life of the field. The pour points and viscosities were found to vary greatly with weathering and thermal history, so previous rheological information may not be accurate. The effect of weathering on the rheology of the oil was studied and results presented.     

矿物基础油对锂基润滑脂流变性的影响

选用不同类型与黏度的11种矿物基础油,以锂基润滑脂为对象,系统研究基础油对流变性的影响,并基于烃类分子水平进行深入探讨。结果表明,同皂量下,线性黏弹区内润滑脂的表观黏度与基础油高度相关,关键决定因素是基础油的倾点,其次是黏度。随链烷烃含量增加,基础油倾点升高,润滑脂的表观黏度随之增大;而芳烃影响则相对复杂,其含量增加时,在降低油品倾点的同时,却增大了黏度,两者的综合作用决定着润滑脂的表观黏度,一般黏度占主导地位。     

流变学及粘度检测技术新发展

文章简述了流变学原理及其三个学派（实效学派、理论学派和学院学派）和观点和方法，概述了流体了主要是非牛顿流体的粘度特性以及影响流体流变特性的诸因素。介绍了８０年代的粘度测量技术和先进的流变分析方法和粘度测量技术。     

膨润土造浆率测定方法探讨

造浆率是勘探行业用膨润土的主要技术指标,利用实验手段确定膨润土的造浆率指标时,事先需要进行大量的摸索性实验工作。由于受检土样技术参数不明确,实验人员操作经验存在差别,导致操作过程的盲目性很大,特别是人工处理实验数据的过程会造成明显误差,致使造浆率指标的测定过程比较繁琐,准确度不高,方法的可操作性较差。室内实验结果表明,利用Excel的趋势线拟合功能能够有效消除上述各环节中存在的误差,并且可以从根本上消除实验过程中的盲目性。实验数据的验证过程证实,以拟合趋势线方程计算得到的膨润土含量为基准配制悬浮液,测得的Fann35黏度计读数与理论值十分吻合,表明该方法可以快速而准确地确定膨润土的造浆率。     

An empirical correlation for estimating the viscosity of non-Newtonian waxy crude oils

Non-Newtonian fluids are the most complex ones when it comes to predicting their flow behavior. In the pre-existing models, rheological behavior in waxy crude oils is mainly affected by shear rate and thermal history of crude oils. In the present work, rheological characteristics of four different crude oils were studied by coaxial cylindrical rheometer at three different temperatures (40°C, 50°C, and 60°C) and a model was proposed keeping into consideration wax content for the first time. This model is prepared to predict the viscosity of four different crude oils with different wax content and at different temperature. The proposed model can efficiently estimate the viscosity as compared to other established models.     

稠油油田边部油井井筒乳化降黏技术研究及应用

渤海某油田边部3口油井投产后产油量低,未达到预测水平。通过与同区块油井对比分析,研究出原因是油井原油黏度高,增加了井筒举升过程中的阻力,影响了电泵效率。优选成本低、降黏率高的井筒乳化降粘的技术工艺,其机理为乳化降粘和润湿降阻两方面。实验表明该复合型稠油助采剂加入定量比例的情况下,可形成黏度在10~100m P·s范围内的乳化体系;并且在温度30~60℃范围内,黏度水平稳定,降粘效果明显。3口油井实施后日均增油26m3,降粘增油效果显著。     

Physical Properties of Petroleum Waxes. I. Effect of Oil Content

The effect of oil content on the physical properties of five microcrystalline waxes having widely different oil content have been investigated. It has been observed that the physical properties are affected to a great extent by the variation in oil content. Oil content has a profound effect on viscosity, hardness, and crystallinity of waxes. The effect is not so profound in the case of melting point.     

Physical Properties of Petroleum Waxes. I. Effect of Oil Content

Abstract

The effect of oil content on the physical properties of five microcrystalline waxes having widely different oil content have been investigated. It has been observed that the physical properties are affected to a great extent by the variation in oil content. Oil content has a profound effect on viscosity, hardness, and crystallinity of waxes. The effect is not so profound in the case of melting point.     

异构脱蜡润滑油基础油组成对其性质的影响

以加氢裂化尾油和加氢处理重质减压馏分油为原料,采用异构脱蜡工艺制备润滑油基础油。分析基础油的性质,并采用质谱和¹³C核磁共振分析异构脱蜡基础油的烃组成和烃结构,考察异构脱蜡润滑油基础油的烃组成和烃结构对其性质的影响。结果表明,对于异构脱蜡润滑油基础油,在多环环烷烃质量分数、链烷碳质量分数和平均碳数相近的条件下,黏度指数随着异构烷碳与正构烷碳质量分数之比的增大而减小,倾点随着异构烷碳与正构烷碳质量分数之比的增大而降低;在多环环烷烃质量分数、异构烷碳与正构烷碳质量分数之比相近的条件下,黏度指数和倾点随着分子的平均碳数减少而降低。     

Practical Applications of a Process Simulator of Middle Distillates Hydrodesulfurization

Abstract

An analysis of the diesel hydrodesulfurization process using a developed reactor model is presented. The reactor model within process simulator architecture was applied to different industrial process schemes. The analysis in this work uses a commercial simulator (Aspen), to conform the process scheme with a user model for the reactor unit. This user model consists of a rigorous diesel hydrodesulfurization reactor model. To couple the user model with Aspen, the kinetic and the reaction network must be available and based on model compounds. The user model employs two model compounds for the hydrodesulfurization reactions. These represent the sulfur families (dibenzothiophene and 4,6-dimethyl-dibenzothiophene). The species take the reactivity range of the sulfur compounds found in the middle distillate fractions of the Mexican crudes. One and two rings aromatic compounds are represented by the cyclohexylbenzene and methylcyclohexyltoluene, the naphthenes by the dicyclohexane and the paraffins by the n-hexadecane. Results obtained are shown by using this model in three industrial plants. The results were used to analyze the critical variables of the process showing good agreement with industrial data. The use and application of the model show the advantages of this tool to analyze actual processes, to test new configurations and the effect on the product quality when different loads with different characteristics or different processability conditions are used.     

Practical Applications of a Process Simulator of Middle Distillates Hydrodesulfurization

An analysis of the diesel hydrodesulfurization process using a developed reactor model is presented. The reactor model within process simulator architecture was applied to different industrial process schemes. The analysis in this work uses a commercial simulator (Aspen), to conform the process scheme with a user model for the reactor unit. This user model consists of a rigorous diesel hydrodesulfurization reactor model. To couple the user model with Aspen, the kinetic and the reaction network must be available and based on model compounds. The user model employs two model compounds for the hydrodesulfurization reactions. These represent the sulfur families (dibenzothiophene and 4,6-dimethyl-dibenzothiophene). The species take the reactivity range of the sulfur compounds found in the middle distillate fractions of the Mexican crudes. One and two rings aromatic compounds are represented by the cyclohexylbenzene and methylcyclohexyltoluene, the naphthenes by the dicyclohexane and the paraffins by the n-hexadecane. Results obtained are shown by using this model in three industrial plants. The results were used to analyze the critical variables of the process showing good agreement with industrial data. The use and application of the model show the advantages of this tool to analyze actual processes, to test new configurations and the effect on the product quality when different loads with different characteristics or different processability conditions are used.     

气相色谱-飞行时间质谱表征馏分油芳烃分子组成的馏程分布

建立了气相色谱-飞行时间质谱表征馏分油芳烃分子组成馏程分布的分析方法。以不同环数芳烃标样的"沸点-色谱保留时间"关系曲线为芳烃试样色谱图馏分切割的依据,利用此方法表征了试样Y中芳烃的分子组成、平均相对分子质量和平均结构的馏程分布。实验结果表明,各馏分段中芳烃的平均相对分子质量与此馏分段的温度呈良好的线性关系,相关系数为0.995 4,可由此预测芳烃试样在任意馏分段的平均相对分子质量;在相同馏分段中,芳烃不饱和度越高,平均碳数和平均相对分子质量越小,侧链碳率越低。该方法开拓了分子水平表征石油及其产品的新思路。