Rheology of Middle Distillate. I. Role of Composition

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.     

STUDIES ON THE PLOW PROPERTIES OF VACUUM GAS OIL FRACTION FROM BOMBAY HIGH CRUDE OIL IN RELATION TO ITS COMPOSITION

ABSTRACTS

The vacuum gas oil fraction 375–Crude oil is highly waxy in nature associated with high pour point (48°C). Influence of various hydrocarbon constituents viz. n-alkane, aromatic and iso + cycloparaffins on the cold flow properties of this fraction was studied. Also the dependency of nature and boiling range of liquid hydrocarbon solvent matrix on the response towards cold flow properties as a function of n-alkane concentration have been determined. It is observed that the flow properties viz. pour point, plastic viscosity and yield stress in the non-Newtonian region are a result of wax liquid matrix interaction.     

Catalytic Dewaxing for Lube Oil Production

Abstract

The selective cracking of long-chain normal paraffin's of medium neutral raffinate, derived from a lube oil-phenol extraction unit, by the catalytic dewaxing technique over H-ZSM-5 and NiMo-H-mordenite catalysts was studied. The runs were conducted to produce lube oils with acceptable cold flow properties. The influences of zeolite types, metals loading, and operating reactor temperatures (290°C–475°C) can have a great effect on cracking high pour point n-paraffins into lower ones, and hence a reduction in pour points. An increase in temperature (between 290°C and 375°C) increased wax conversion (percent dewaxing) on H-ZSM-5 compared with NiMo-H-mordenite catalysts due to its higher cracking activity. As a result, large amounts of C₁-C₄ gases and C₅-170°C naphtha were produced. The low pour point lube oils produced from catalytic dewaxing over H-ZSM-5 compared with NiMo-H-mordenite catalyst indicates that the former was more selective for removing wax components than the later. On the other hand, high concentrations of aromatics were obtained on both catalysts, since the waxy paraffins are converted to lower boiling products. The reduction in dewaxed pour points (Δpp) was observed to be in the range of 38°C–42°C over H-ZSM-5, compared to 37°C–40°C over NiMo-H-mordenite at the same reaction temperature ranges (290°C–375°C), but NiMo-H-mordenite has advantages at higher temperature ranges (above 375°C) in pour point reduction (Δpp range: 41°C–42.5°C). The addition of bimetallic components to the mordenite-catalyst enhances its activity, and the rate of normal paraffin cracking was increased due to the hydrogenolysis activity of the active metals. This means that the bimetallic H-mordenite catalyst has the advantage over H-ZSM-5 in its refining activities (hydrodesulfurization [HDS] and hydrodenitrogenation [HDN]) under the tested operating conditions. These results may be attributed to shape-selective discriminating behavior due to differences in zeolite pore openings (i.e., 6.5 × 7.0 Å for mordenite and 5.3 × 5.6 Å for ZSM-5). In other words, a combination of isomerization and selective cracking reactions of high n-paraffins may occur during the dewaxing process using NiMo-H-mordenite catalyst. The influences of process parameters (temperature, pressure, and liquid hourly space velocity [LHSV]) on the relations between wax conversion to maintain maximum low pour points and maximum dewaxed oil yields or minimum yields of the least desired gases were optimized to produce dewaxed lube oils of acceptable characteristics.     

Thermodynamic Aspects of Aromatic Hydrogenation

Abstract

Aromatic hydrogenation is one of the important classes of hydrotreating reactions and its thermodynamics play a significant role in achieving the product specifications. This article comprehensively reviews the available experimental thermodynamic data as well as the methods to estimate the data for aromatic hydrogenation. The data indicate that aromatic hydrogenation reactions are thermodynamically more favorable at about 200°C–250°C and moderate pressures (3–5 MPa). Industrially, however, these reactions are carried out at 300°C–375°C to have reasonable kinetics. Hence there is a need for highly active catalysts, which can facilitate significant kinetics of hydrotreating reactions at around 200°C–250°C.     

Modeling of oil generation by Domanik carbonaceous shale

Experiments on artificial maturation of carbonaceous rock of the Domanik age in an autoclave in the presence of water at temperatures of 250, 275, 300 and 325°C have been performed. It has been shown that a significant amount of soluble organic matter (OM) is produced from insoluble OM under these conditions. Changes have been observed in both the biomarker composition of the bitumen and the Rock-Eval OM maturity parameters characteristic of natural catagenesis. By the solid-state ¹³C NMR technique, it has been shown that the amount of aliphatic units decreases and that of aromatic units increases in residual kerogen. Study the product composition of the pyrolysis of residual kerogen has revealed that the relative amount of precursors of n-alkyl structures increases as compared with low-molecular-weight aromatic and thiophenic structures.     

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     

Characterization of Thermally Degraded Asphaltene Fractions Using Gel Permeation Chromatography

Abstract

Petroleum asphaltene goes through three stages of mass reduction under thermogravimetric analysis from 25°C to 1,000°C at a heating rate of 1°C/min. The products from thermal degradation of asphaltene at three different temperature intervals are collected. Two residual fractions left in the sample cup are also obtained at two specific temperatures. The collected fractions and the residual fractions are characterized using gel permeation chromatography. The fraction collected between 25°C and 350°C demonstrates similar molecular weight distribution to that collected between 350°C and 450°C, with both fractions showing a typical molecular weight distribution for polymeric material. The fraction collected between 450°C and 650°C illustrates three different molecular weight distributions. The chromatogram of the residual fraction obtained at 350°C resembles that of the undegraded asphaltene. The residual fraction obtained at 450°C also demonstrates three different molecular weight distributions. The experimental data indicate that the mass reduction of asphaltene heated from 25°C to 350°C is mainly due to the evaporation of low boiling point and/or low molecular weight substances in asphaltene. Thermal decomposition and coke production occur significantly in the 350°C–450°C temperature interval. Thermal degradation continues to finish until 650°C.     

THE EFFECT OF ANTIOXIDANT ADDITIVE ON THE THERMOXIDATION STABILITY OF DISTILLATES FROM MEDIUM CRUDE OIL

ABSTRACT

Fractions 100-150, 150-200, 200-250°C were distilled from medium Iraqi crude oil. The thermo-oxidation stability experiments were carried out on original and inhibited (with Topanol 0) distillate fractions using the Alcor Jet Fuel Thermal Tester, over a temperature range 516-573 k. It was found that the antioxidant (Topanol 0) efficiency depends on the fractions composition and the oxidation temperature. Only 30 PPM of Topanol 0 stabilizes fraction 100-150°C to a considerable extent. Also, an inhibition effect is obtained in fraction 150-200°C but at a higher antioxidant concentration (90 PPM). Only, slight inhibition effect was observed in fraction 200-250°C at low oxidation temperature (below 551 K), while effect will be of no value at higher oxidation temperatures.     

Conversion of resin-asphaltene substances under conditions modeling the thermal methods of enhanced oil recovery

The composition of the products of hydrothermal conversion of a natural concentrate of resin-asphaltene compounds (asphaltite) at temperatures of up to 575°C was studied within the scope of laboratory-scale simulation of transformations of high-molecular-mass components of reservoir oils using the thermal methods of enhanced oil recovery. It was found that thermal degradation takes place in the range 175–575°C, leading to the formation of gases, in particular H₂S, and liquid and insoluble products (oil and carbenes-carboids, respectively). The amount of saturated and aromatic compounds in the liquid products of hydrothermal conversion is greater than in the starting sample. The ratio of benzene-extractable to alcohol-benzene-extractable resins substantially varies in favor of the latter compounds, which are enriched in oxygen-containing structural units. The relative amount of higher (>20°C) n-alkanes in the products of conversion at 175–325°C or 350–575°C is respectively higher or lower than in the virgin asphaltite. At conversion temperatures of ≥400°C, the products contain α-olefins.     

Preparation of synthetic hydrocarbon oil by high-pressure hydrocracking of ethylene-propylene copolymers

Degradation reactions of ethylene-propylene copolymers at a high temperature (380–430°C) and a high pressure (180–220 atm) in the presence of a nickel catalyst and hydrogen have been studied. In contrast to the previously known processes, the degradation reactions have been conducted simultaneously with hydrogenation reactions. The effects of temperature, pressure, and time on the yield of each fraction have been examined. As a result, optimal process conditions have been found for each fraction. The physicochemical properties of the lube oil fraction (C₁₈–C₂₅) used as a base oil have been studied. It has been found that as in the case of oils derived from ethylene-propylene copolymers by other methods, these oils have a high viscosity index (VI > 95), a high flash point (T _f > 210°C), and a low pour point (T _p < ?50°C).     

合成烃类航空润滑油高温金属催化氧化研究

利用高温氧化加速实验装置,以金属Cu、Fe作催化剂,研究合成烃类航空润滑油在温度为180,200,230,250,300 ℃条件下的氧化反应,测定反应后油品的运动黏度、酸值及倾点,并结合二元相关方法计算三者间的相关系数,利用GC/MS对其组成进行分析。结果表明：油品的运动黏度与酸值、运动黏度与倾点的关系为高度负相关性,酸值与倾点的关系为高度正相关性;正构烷烃、异构烷烃、烯烃以及其它化合物的相对含量与氧化后油品的酸值及倾点的变化具有高度正相关性,但与运动黏度的变化呈高度负相关性;己二酸二异辛酯及抗氧剂的相对含量与氧化后油品的酸值及倾点的变化具有高度的负相关性,而与运动黏度的变化呈高度正相关性。     

The Formation of Waxy Crude Oil-in-water Emulsions for the Reduction of Pour Point and Viscosity

Waxy crude oil is characterized by high pour point and poor flow properties, which bring great difficulty to the oil exploitation and transportation. In this study, the fluidity of waxy crude oil with the pour point of 47°C was highly improved by emulsification with synthetic formation water used as aqueous phase. It was found that the combination of CAO-35 and sodium oleate was an effective emulsifier mixture to form stable waxy crude oil-in-water emulsion and when the mass ratio of oil to water was 7:3, the optimum composition of emulsifying additives with respect to the total mass of the emulsion was obtained as follows: emulsifier mixture (the mass ratio of CAO-35 to sodium oleate was 8:2) 0.4% (w/w), sodium triphosphate 0.028% (w/w), NaOH 0.05% (w/w), and polyacrylamide 0.15% (w/w). Diverse factors affecting the pour point of the formed emulsion were also studied. It was found that the pour point of emulsion increased as oil content increased and the optimum mixing speed and cooling rate were 600 rpm and 0.5°C/min, respectively. Under the optimum emulsifying conditions, when mixing speeds were 250 and 600 rpm, respectively, by forming O/W emulsions with the oil content of 70%, the pour point reductions were 20 and 25°C, respectively, and the corresponding viscosity reductions were 89.79% and 97.46% (40°C), respectively. Thus the pour point and viscosity of waxy crude oil are obviously reduced by forming oil-in-water emulsion, which is highly promising for the exploitation and transportation of waxy crude oil.     

Conversion of triglycerides to fuel hydrocarbons over a Pt–Pd–Al–HMS catalyst

The hydroconversion of rapeseed oil fatty acid triglycerides (TGs) over a mesoporous platinum–palladium aluminosilicate catalyst has been studied. It has been shown that, in a temperature range of 250–375°C at a hydrogen pressure of 60 atm, the TGs undergo complete deoxygenation and the resulting products undergo isomerization. Under optimum process conditions, the diesel fraction yield is 94%. The resulting fraction can be used as an environmentally safe fuel component.     

Comparative Evaluation of Catalysts Containing 0.35% Pt Supported on H-BEA Zeolite Dealuminated via EDTA,HCl Leaching,or Hydrothermally With Steam

Abstract

H-BEA was steamed at 500°C for 2 hr and then loaded with Pt to produce 0.35% Pt/St-H-BEA catalyst. Also, H-BEA was dealuminated with ethylenediamine tetraacetic acid (EDTA) and then loaded with Pt to produce 0.35% Pt/EDTA-H-BEA catalyst. Finally, H-BEA was dealuminated via HCl leaching followed by Pt loading to produce 0.35%Pt/HCl-H-BEA catalyst. These catalysts were reduced under H₂ flow at 500°C to give Pt metal. All catalysts were tested at 250°C–450°C for n-hexane hydroconversion. Maximum hydroisomerization of n-hexane was attained (75.1%) on 0.35% Pt/EDTA-H-BEA and 0.35% Pt/HCl-H-BEA catalysts but at 275°C on the former catalyst and at 300°C on the latter. At this temperature, n-hexane hydrocracking is only 1.2%. The hexane isomers selectivity on both catalysts was >99%. For the 0.35% Pt/St H-BEA catalyst, isohexanes yield and selectivity were lower than the above-mentioned catalysts. The catalyst of choice is 0.35% Pt/EDTA-H-BEA for its economic application at 275°C.     

Hydrothermal transformations of organic matter of low permeability rocks from domanic formation of the romashkino oil field

Abstract

The oil generating potential of Domanic rocks from Dankov–Lebedyan horizon of the Zelenogorsk area of Romashkino oil field was evaluated by Rock-Eval pyrolysis technique. The result of given method depends on the content, composition, and thermal stability of organic matter in rocks. During hydrothermal processes, the distinctive conversion behavior of organic matter at temperatures of 200°С, 250°С, 300°С, and 350°С in CO₂ environment was revealed. The yield of obtained aquathermolysis products and their quality were evaluated. The results of the studies suggest that low-permeability carbonate rocks of the Dankov–Lebedyan horizon contain productive beds with content of C_org 1.89–3.03%, which when developed using thermal methods, can become an additional source of liquid hydrocarbons.     

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

ABSTRACT

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.     

LOW TEMPERATURE FLOW CHARACTERISTICS OF SOME WAXY CRUDE OILS IN RELATION TO THEIR COMPOSITION : PART I WITH AND WITHOUT POUR POINT DEPRESSANT ADDITIVES

ABSTRACT

The yield stress, plastic viscosity and apparent viscosity and the dependence of the latter on the shear rate have been studied at different temperatures below pour point of Lingala (Krishna-Godavari basin, Eastern coast), Duliajan (Eastern region of Assam), Rava (Godavari basin) and Bombay-High (off-shore western region) indigenous crude oils

Four different commercial pour point depressant additives have been used to study their effects on the pour point, yield stress and plastic viscosity

From this study it has been found that wax concentration and its composition are primarily responsible for the variation in the pour point, and crude base composition has a small effect. However, the response of the pour point depressant additive in effecting the change in the pour point is primarily governed by the liquid matrix. As the temperature is lowered both the yield stress and plastic viscosity increase in case of each crude oil. However, the magnitude is dependent on the nature of the crude oil. With pour point depressant additives, the yield stress and plastic viscosity are decreased and this decrease is a function of nature of the liquid matrix of the crude oil and concentration of the additive     

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

Abstract

The high viscous crude oil from Shuguang No. 1 zone of Liaohe oil field has the characteristics of high density (ρ ₂₀ = 0.9977 g cm^?3), great viscosity (ν ₁₀₀ = 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.     

Characteristics of organic acids in lacustrine organic-rich shale,Ordos Basin,China

Organic acids are critical to studying the formation of secondary porosity in tight lacustrine reservoirs, Ordos Basin. The expelled fluids produced through hydrocarbon evolution in a semi-closed system under different pressure and temperature settings (16.9?MPa, 250?°C; 22.1?MPa, 300?°C; 32.5?MPa, 350?°C; 37.7?MPa, 370?°C; 42.9?MPa, 400?°C; and 52.2?MPa, 450?°C) were collected. In this study, 12 different organic acids were identified using ion chromatography, and both the concentration and species of organic acids indicate a two-step process.     

Transformations of hydrocarbons of Ashal’hinskoe heavy oil under catalytic aquathermolysis conditions

The influence of temperatures of 250, 300, and 350°C on the character of changes in the group and hydrocarbon compositions of heavy oil from the Ashal’chinskoe field in laboratory experiments on the simulation of oil aquathermolysis processes under reservoir conditions has been revealed. The experiments have been carried out in the presence of kaolin as a rock-forming mineral, using oil-soluble iron carboxylate and tetralin as a proton donor. It has been shown that temperature elevation to 300 and 350°C increases the amount of saturated fractions by factors of 1.5 and 1.75, respectively, and decreases the resin content almost by half in comparison with the initial oil. The proportion of n-alkanes and light alkylcyclohexane and trimethylalkylbenzene homologues in the saturated fractions increases as a result of cracking reactions involving the preferential degradation of high-molecular-weight resins. A noticeable increase in the amount of newly formed hydrocarbons and asphaltenes at the temperature of 350°C indicates that not only intensive cracking processes, but also condensation processes occur under these conditions. Changes in the quantitative and qualitative composition of the proton donor tetralin by its dehydrogenation to form naphthalene and hydrogenation to yield the cis- and trans-isomers of decalin have been revealed.