SEPARATIONS AND CHARACTERIZATIONS OF FRACTIONS FROM MAYAN,HEAVY ARABIAN,AND HONDO CRUDE OILS

ABSTRACT

Mayan, Heavy Arabian, and Hondo crude oil resids have been separated with a modified, extended ASTM D2007 procedure. The fractions obtained have been characterized with various analytical techniques. Chemical properties, hydrodesulfurization, and hydrodemetallation activities of the resids have been correlated with the chemical properties of the separated fractions. Many correlations were indicative of the overall bulk properties of the resids and the broad chemical classes obtained from the separation schemes. Other correlations reflected the unique chemical nature of each crude oil resid. Some potentially important correlations were found between hydrodesulfurization activity and sulfur concentration in polars and asphaltenes, and between hydrodemetallation activity and nitrogen concentration in the acid and bases fractions.     

PHYSICAL AND CHEMICAL PROPERTIES OF CORNCOB FOR THERMAL CONVERSIONS

Abstract

In order to increase thermal efficiency and reduce pollution, it is necessary to understand the physical and chemical properties of corncob for the service of its gasification and liquefaction. Physical properties of melting point, cohesiveness, heating value, specific gravity, thermal conductivity and specific heat, and chemical properties of chemical composition (cellulose, lignin, semi-cellulose, extractives and ash), element composition (C, H, O. S. N), industrial analysis (content of water, ash, volatile and fixed carbon), reactivity and volatility of corncob have all been tested or collected.     

MODELLING OF HYDROTREATING PROCESS IN A TRICKLE-BED REACTOR

ABSTRACT

Pilot scale hydrotreating experiments have been conducted on straight run high speed diesel oil (SR HSDO)using commercially available Co-Mo on Al₂O₃ catalyst. Kinetics of hydro-desulphurization and hydrodenitrogenation are studied using the models that took into account the physical and chemical complexities of the three phase system. Correlations are developed to predict the product properties based on operating conditions. The results show a good agreement with the experimental data.     

Influence of Asphaltenes on the Rheological Properties of Blended Paving Asphalts

Abstract

Some of the refineries in India produce asphalt by blending propane deasphalting (PDA) pitch and heavy extract. This investigation reports the rheological and chemical characterization of various blends made with PDA pitch and heavy extract. The main objective is to develop an understanding on the influence of asphaltene change on the changes in the rheological properties under all aged conditions. Three blend proportions were manufactured using three different crude sources, and all the blends were subjected to short- and long-term aging. All the blends were tested for steady shear, creep and recovery, and stress relaxation properties. A chemical composition analysis of all the blended asphalt samples was carried out under all three aging conditions. It was seen that the proportion of PDA pitch considerably controls the rheological properties and that the kinetics of short-term aging are completely different when compared to long-term aging for blended asphalt.     

AN IMPROVED INHIBITION OF PARAFFIN DEPOSITION FROM WAXY CRUDES

ABSTRACT

A series of cold spot tests of progressively increasing complexity was employed to evaluate the potential of several chemical additives for inhibiting paraffin deposition from waxy crudes. Test data revealed that trichloroethylene-xylene (TEX) binary system has a unique ability to effect substantial pour point depression and improved transport properties for a wide range of waxy crudes. This led to improved inhibition of paraffin deposition by TEX additive in comparison with the perfonnance of some tested, commercial anti-paraffin chemical products.     

CHARACTERZATION OF VENEZUELAN HEAVY OIL VACUUM RESIDUA

ABSTRACT

Vacuum residua from Venezuela heavy and medium oils upgraded under the same conditions ware characterized using different analytical techniques: TLC-FID, H NMR, HPLC, SEC-DCP. Parameters or chemical properties such as crude maturity, size distibution of hydrocarbons and metal compounds. asphaltene characteristics, sulphur contents, correlate with the process-ability of these heavy ends.     

Experimental Investigation on Binary Compound System Performance Changes During Migration

Abstract

The authors created a 30 m long physical model. Many sampling points are arranged on different location of the model. By collecting sample at the real time, chemical concentration, viscosity, and other properties of binary compound system were measured separately. Results from the experiment show that from model import to model export, the chemical concentration and viscosity of binary system is gradually declining. The loss of surfactant concentration is much larger than that of polymer concentration, and viscosity loss of the binary system is greater than concentration loss of polymer.     

Studies on Nigerian Crudes IV. Improvement of Asphaltic Properties of Residual Asphalts

Abstract

Residual asphalts obtained from 25 samples of Nigerian light, medium, and heavy crude oils were chemically treated by air-oxidation and sulfurization to improve their characteristic properties. The asphalt yield for light crudes varied from 27.7–33.7 wt% and 33.4–67.5 wt% for medium crudes. The chemical treatment brought about changes in chemical composition, increase in molecular mass and modification of consistency resulting in highly improved asphaltic properties. There were manifold increases in viscosity and softening points, which came as a result of the higher asphaltene content of the treated materials. The asphalts obtained meet quality specifications for typical commercial grade products thus confirming the suitability of Nigerian crude oils for the production of residual asphalts.     

An Experimental Investigation of the Impact of Diffusion Osmosis and Chemical Osmosis on the Stability of Shales

Abstract

Wellbore instability in shales is the most challenging and costly issue in drilling operations. Wellbore instability in shales can be attributed to many factors, some of which have been well studied and documented. However, the physicochemical and mechanical properties alterations in shales that eventually lead to wellbore failure have been largely ignored. Water and ion movements in and out of shales play a major role in the alteration of the physicochemical and mechanical properties of shales, thus leading to wellbore instability problems and possible hole collapse. Water and ions can move in and out of shales by many mechanisms, including, but not limited to, diffusion osmosis, chemical osmosis, convective flow, and capillary suction.

This work presents experimental data analyzing the impact of chemical osmosis and diffusion osmosis on water and ion movements when shale interacts with drilling fluids. The adopted experimental work minimized the effect of convective flow and capillary suction. Results show that water movement is not only controlled by chemical osmosis (water activity) as previously thought but is also influenced by diffusion osmosis. This insight provides information and guidelines to optimize drilling fluids to effectively control and mitigate wellbore instability when drilling through troublesome shale.     

KINETIC PARAMETERS OF HYDROPROCESSING REACTIONS IN A FLOW REACTOR

ABSTRACT

The change in distillation properties of a blend of light and heavy distillates over a commercial hydrotreating catalyst was studied using a small packed bed reactor. The results were interpreted assuming a pseudo-component model that took into account the physical and chemical complexity of the system. A first order series-parallel reaction mechanism was found to be valid for the operating conditions involved. Pore diffusion effects were also taken into consideration.     

CHARACTERIZATION OF HEAVY AND MEDIUM OILS FROM SASKATCHEWAN RESERVOIRS

ABSTRACT

Physical and chemical properties of oils are not available for most of Saskatchewan reservoirs. Hence, standard and specialized oil and water analyses were performed on fluids obtained from nineteen medium and heavy oil reservoirs. Seven of these reservoirs are producing under steam and fireflood processes.

The results of the oil analysis suggest that thermal history of the oil can be monitored by GC-MS techniques and viscosity measurements. 011 samples from different wells within a reservoir demonstrated significant differences 1n density, viscosity and other properties.

The water analysis data show that the variation in resistivity, total dissolved solids, pH and the concentration of the Ions present 1n the wellhead water samples as a function of time could be a useful Indicator for the flow pattern and flushing efficiency of steam or the advancement of the firefront and the extent of oil oxidation during thermal recovery processes.     

Influence of Chemical Composition on the Physical Characteristics of Paving Asphalts

Abstract

The simplest general compositional model considers asphalt to be made up of asphaltenes, heavy oils, and resins. In the present study the extent of similarity between the properties and composition of various types of asphalt obtained from different sources has been carefully explored. It shows how ductility, penetration, and softening point are related to the chemical nature of paving asphalts in the range 41–58 softening points. Asphalt properties are found to be a direct function of its chemical constituents. The relationship between softening point and asphaltene content was found to be linear while asphalts of the same softening point are easily distinguished by the content of the resins. Evaluation of the two asphalt indices—the asphaltene index (I _A ) and the Gaestel index (I _C ), reveals that they both vary linearly with the composition of asphaltenes and resins thus confirming their suitability in the characterization of asphalts. Comparison of the two indices shows that IC is more suitable in estimating the colloidal stability of different groups of asphalts. The observed correlations can be found useful in the areas of asphalt blending and rejuvenating through the appropriate selection of asphalt components.     

The solubility of gases under pressure in liquid propellants

Abstract

A corresponding states correlation has been developed for the solubility of pure gases and mixtures in LGP 1846, a HAN based liquid propellant [1]. For nitrogen, methane, xenon, krypton, and argon, and their mixtures the correlation can be used to estimate gas solubilities for pressures upto 100 MPa in the temperature range 258 < T < 303 K. The correlation is in satisfactory agreement with all available experimental data for these systems. Dissolved gases are expected to significantly effect many physical and chemical properties of liquid propellant systems.     

DETERMINATION OF THE CONTINUITY IN OIL RESERVOIRS USING PRINCIPAL COMPONENT ANALYSIS OF BIOMARKERS DATA

ABSTRACT

In order to develop an optimum production scheme in an oil reservoir it is very important to determine accurately the internal geometry (continuity and compartmentalisation). Usually geophysical logging methods are used for this purpose, which are expensive and time consuming. Additional information can be derived on the basis of differences in physical properties and/or in chemical composition within oil samples produced from separate compartments in a reservoir. The major problem is that oil samples coming from the same formation exhibit minor physico-chemical differences. Hence, it is difficult to develop a reliable discriminating algorithm. This paper presents a novel analytical approach, which enables accurate discrimination between the oil samples coming from different wells in a layered reservoir, which exhibit minute differences in physical and in chemical properties. The method uses the biomarkers data obtained from the GC–MS m/z 191 fragmentogram of the saturated fraction of the oils. Principal Component Analysis (PCA) method was applied to discriminate oils into groups. The classification scheme obtained using the proposed analytical method was found to be in agreement with the available geological and geophysical data, which describes the internal geometry of the reservoir under study.     

Effect of Catalysts on Effluents During Air Blowing of Asphalt

Abstract

Air blowing of asphalt was performed in presence of catalysts. The effluents (distillate) obtained during air blowing were analyzed to see the effect of catalysts on them. This study investigates the effluents in detail, using physical and chemical methods. Catalysts used were metallic chlorides in varying quantities and also in combination with manganese dioxide. The aim of using different catalysts was to develop a suitable catalyst, which can perform hardening of asphalt at par with other available catalyst, at the same time keeping the effluents relatively low and free of acidic gases. These acidic gases decrease the life of the plant and cause environmental problems. During a 15 h air oxidation period, it was observed that for feed I asphalt the physical (specific gravity & viscosity) and chemical (acidity & composition) properties of the effluent oils, were effected by the catalysts. Amount of effluents were different for different catalysts. Saturate contents of the effluent were increased due to catalyst, while naphthalene and polar aromatic decreased. Effluents were free of asphaltene. The variation in the properties of effluents obtained during feed asphalts II and III air blowing, were not so distinct than with feed I. It indicates that the extent of changes in the properties of effluents depends on the composition of feedstock. Effluent oils were investigated by instrumental analytical techniques such as GLC, UV. Some of the properties of blown asphalt are also reported.     

A Study on the Coke Behaviors During Alkylation of Benzene with Ethanol Over Different HZSM-5 Catalysts

Abstract

Four different kinds of HZSM-5 zeolites with different acid properties and crystal size were used as catalysts in alkylation of benzene with ethanol to produce ethylbenzene and the coke behaviors were studied. The catalysts were characterized by X-ray diffraction (XRD), Brunacr-Emmett-Teller (BET), scanning electron microscopy (SEM), wet chemical analysis, NH₃-temperature programmed desorption (TPD), and Py-infrared (IR). The coke amount was measured by thermal gravity (TG) and the nature of the coke deposition was characterized by ultraviolet-visible (UV-Vis) and C/H analysis. The results showed that besides acid property, the crystal size could also affect the catalytic performance, coke content, and the nature of the coke deposition. The effect of reaction conditions including temperature, weight hourly space velocity, and time on stream on the catalytic performance and coke behaviors were also discussed over S-4.     

OIL COKING PROPENSITY UNDER HYDROPROCESSING CONDITIONS

ABSTRACT

If the processability of heavy or residual oil is assessed in terms of conversion to distillate oils, the tendency to form carbonaceous (coke) deposits in the reactor would impose limits on the operating conditions, since any significant coke accumulation on a continuing basis would be prohibitive. Experimentally, one can evaluate the feedstock coking propensity in a bench-scale reactor for a set of typical hydroprocessing conditions by varying the temperature near the threshold of coking. For a number of different feedstocks examined by this method, an empirical function can be found correlating the coking propensity with some of the characteristic properties determined by routine analyses. The present approach used a combination of physical and chemical properties including density and contents of Conradson Carbon residue, pentane and toluene in-solubles, fraction of high-boiling pitch, and carbon, hydrogen, nitrogen, sulfur and ash. Feedstocks were chosen to cover a wide but practical range of properties to establish their impact on the coking propensity. Although these relationships apply to thermal hydroprocessing, the role of catalysts is also indicated.     

CHEMICAL CHARACTERIZATION OF ROADWAY ASPHALT

ABSTRACT

The condition of ten roadways constructed between February 1983 and Hay 1984 has been evaluated with respect to distortion, cracking, raveling, rutting, and overall condition. These observations have been correlated with laboratory measurements of rheological and chemical properties of the refinery liquid from which the roadway was made. Rheologic parameters include penetration, ductility, and viscosity. Chemical measurements include elemental analyses, fractionation into asphaltenes, oils, and resins, infrared and C-13 nuclear magnetic resonance spectra, molecular size of asphalt components by high performance liquid chromatography, and solvent solubility     

Prediction of transient pressure change during natural gas hydrate formation

Abstract

The increasing demand for fossil fuels and diminishing natural energy reserves have necessitated the exploration of gas hydrates. Gas hydrates find importance in oil and gas industries where the formation and dissociation of gas hydrate become important. Thus, the proper understanding of formation, decomposition and properties of gas hydrates is a required. In this work, a macroscopic kinetic model is analyzed and modified to predict the pressure change with time during the hydrate formation based on the chemical affinity of compounds. With the help of experimental data, the degree of parity of the modified and unmodified models are explained. The dependency of the chemical affinity of the gas hydrate reformers is explained based on the kinetic model validation with the experimental results. The modified model predict the transient pressure during gas hydrate formation with an average absolute error of 3.6%.     

THE ANTI-STRIPPINC PROPERTIES OF BASIC NITROGEN IN HYDROCRACKED RESIDS

ABSTRACT

The hydrocracked residues were found to be considerably enriched both in total nitrogen and in basic nitrogen relative to total nitrogen with respect to the feed asphalt. The matrix in which these basic nitrogen components are most likely to be found consisted of compact aromatic structures containing relatively few naphthenic and paraffinic moieties

Upon hydrocracking, the basicity of the remaining basic nitrogen increased with the level of conversion. It is this increased nitrogen basicity which most probably accounted for the enhanced anti-stripping properties of the hydrocracked residues.

Hot storage, such as could be expected during the transportation of the paving asphalt, resulted in the apparent loss of approximately 10%, on average, of basic nitrogen without a commensurate decrease in the anti-stripping effectiveness of the additive. Possible explanations lie in the chemical reactivity of the asphaltic binder

Attempts at isolation of a basic nitrogen concentrate have met with a modicum of success. Indications are that the nitrogen compounds extracted depend largely on the method of extraction