Efficiency of the Stage of Liquid-Phase Thermal Destruction of Petroleum Residues

Optimization of cracking process parameters, which determine the efficiency of the reaction volume, is the most important problem in creating industrial stages of thermal destruction of “native” petroleum residues – atmospheric and vacuum resids. A simplified approach to design of the reaction apparatus for refining such residues will result in large differences in these parameters during use and is due to insufficient information on the colloidal state of the feedstock mixture, kinetic characteristics of its conversion, and hydrodynamics of the material streams in the reaction volume.__________Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 3, pp. 24 – 26, May – June, 2005.     

Methods of Analysis of High-Wax Crude Oils. Resins,Asphaltenes, Paraffin Waxes

Methods of determining the content of resins, asphaltenes, and paraffin waxes and distillation of the waxes applied to high-wax crudes are reported. The method is based on the experience from many years of research on ozocerites, minerals of petroleum origin that primarily consist of paraffin waxes, and crudes with a high wax content.__________Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 3, pp. 48 –50, May – June, 2005.     

A Composite Additive for “Heavy” Gas-Condensate Diesel Fuel

A composite additive that decreases the cloud and solid points of GShZ gas-condensate diesel fuel, stable condensate “heavy” bottoms, to the values required by GOST 305–82 for grade “3– 45” petroleum diesel fuel, was developed from domestic feedstock. This significantly improves the performance properties of gas-condensate diesel fuel.__________Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 4, pp. 26 – 28, July – August, 2005.     

Assembly of asphaltene molecular aggregates as studied by near-UV/visible spectroscopy: II. Concentration dependencies of absorptivities

The properties of molecular aggregation in toluene solutions of a crude oil and solid asphaltenes are determined almost solely by the concentration of asphaltenes, as shown by absorptivity measurements at 315–750 nm. From non-monotonic concentration dependencies of absorptivities, it is concluded that asphaltene monomers are abundant in solutions with asphaltene concentrations below 1–5 mg/l, while molecular aggregates are effectively formed above 20–25 mg/l. The most stable oligomers are a dimer and a dimer pair (Yen's “nanocrystallite” [NC]). Nanocrystallites act as building blocks for more complex aggregates at asphaltene concentrations exceeding 90–100 mg/l. These optical absorption results are supported by studies of Rayleigh scattering in asphaltene solutions.     

Antiseptics Made from Petroleum Resins

Data are reported on the compositions and technology of production of safe petroleum protective creosote materials based on resinous residues and gasoils from thermal and catalytic processes.__________Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 3, pp. 51 – 54, May – June, 2005.     

Features of Intermediate Layer Formation in Water-Oil Emulsions

New data on the mechanisms of intermediate layer formation in petroleum emulsions are reported. The possibility of structural phase transitions preceding the inversion points of these multicomponent media was experimentally demonstrated. Many features of these transitions are similar to the phase transitions in model dispersions of the Winsor III type. In manufacturing processes, the formation of undesirable “intermediate layers’ can be interpreted as the appearance of a bicontinuous phase at ratios of the volume fractions of water and crude close to unity.__________Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 4, pp. 37 – 39, July – August, 2005.     

Transformations of resins and asphaltenes in photoirradiation

The photooxidative transformations of resins and asphaltenes in petroleum residues were investigated by IR spectroscopy. In photooxidation, these substances undergo both degradation and condensation. Gaseous products are formed in degradation–hydrogen, low-molecular-weight alkanes, formaldehyde, carbon monoxide and dioxide, and in condensation, highly condensed aromatic structures and oxidation products insoluble in organic solvents are formed. __________ Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 5, pp. 39–42, September–October, 2007.     

X-ray structural analysis of disperse petroleum systems

Summary In the example of x-ray structural investigation of petroleum asphalts and an oil containing an additive, feasibility has been demonstrated for studying disperse petroleum systems by means of the x-ray method. Large-scale x-ray scattering has been used to determine the aromaticity factor and structural parameters of the asphalts. Small-angle x-ray scattering has been used to establish that all the asphalts contain particles in the smallest size range with a quasispherical shape, and that the larger particles represent associates made up of these smallest particles.In view of the relative size distribution, it can be concluded that the basic elements constituting the submicroscopic colloidal structure are associates with sizes of 78–99 and 136–147 Å.It has been shown that calcium naphthenate in oil solution exists in the form of associates with sizes up to 400 Å.Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 11, pp. 37–39, November, 1974.     

Influence of soil moisture on the results of surface geochemical survey applied to petroleum exploration

The quality of results obtained from surface geochemical exploration depends not only on the character of deep petroleum accumulations but also on the influence of many sub-surface factors. One of important factors is the presence of soil moisture in the sampling interval. This research presents the influence of soil moisture on concentrations of gaseous hydrocarbons in sampled soil gases. The comparative analysis was made on for two populations of gaseous hydrocarbon (methane, ethane, propane, i-butane, n-butane, propylene, 1-butene) concentrations measured in soil gas samples collected from the water-saturated (“wet” sampling interval) and water-free (“dry” sampling interval) environments. The comparison was based upon chromatographic analyses of 2974 samples of soil gas, in which 684 samples originated from “wet” sampling intervals and 2290 samples were taken from “dry” interval. Samples were collected in the areas of known gas deposits located in the Fore-sudetic Monocline (SW Poland). Samples collected from the “wet” intervals reveal higher concentrations of almost all analyzed hydrocarbons in comparison with samples from “dry” intervals. Highest differences were observed for methane concentrations and lowest — for total alkanes C₂–C₄. The increase of concentrations in “wet” sampling intervals can be explained by sub-surface accumulation of hydrocarbons caused by decreasing permeability of water-saturated soils, by the different solubilities of alkanes and alkenes in water as well as by recent generation of methane and alkenes. Considering the results obtained from the area of the Tarchaly gas deposit, it was found that surface pattern of methane anomalies does not reflect the presence of deep gas accumulations, as well as the total alkanes C₂–C₄ distribution. Hence, the procedure was proposed of elimination of soil moisture influence on the pattern of surface methane anomalies. The procedure includes normalization of measured methane concentrations to the reference levels of geochemical background, which characterize “wet” and “dry” sampling intervals. As a result, the distribution of anomalous methane concentrations was obtained, which, along with the distribution of total alkanes C₂–C₄, confirms the presence of assessed accumulation of gaseous hydrocarbons. Therefore, the proposed method is correct and supports the application of methane indicator as a petroleum exploration tool.     

PHYSICAL AND CHEMICAL CHARACTERIZATIONS OF ASPHALTENES FROM DIFFERENT SOURCES

ABSTRACT

Asphaltenes and resins are two of the several, but important, heavy organics present in petroleum fluids. Asphaltenes are operationally defined as the non-colatile and polar fraction of petroleum that is insoluble in n-alkanes (i.e., n-pentane). Conversely resins are defined as the non-colatile and polar fraction of petroleum that is soluble in n-alkanes (i.e., n-pentane), and aromatic solvents (i.e., toluene), and insoluble in ethyl acetate. A commonly accepted view in the petroleum chemistry is that crude oil asphaltenes form micelles which are stabilized by adsorbed resins kept in solution by aromatics. Two key parameters that control the stability of asphaltene micelles in a crude oil are the ratio of aromatics to saturates and that of resins to asphaltenes. When these ratios decrease, asphaltene micelles will coalesce and form larger aggregates. The precipitation of asphaltene aggregates can cause problems such as reservoir plugging and wettability reversal.     

Group composition and properties of petroleum wax fractions

The group chemical composition and physicomechanical properties of petroleum wax fractions are investigated. The mechanism of their change with an increase in the average distillation temperature is determined.Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 1, pp. 47 – 48, January – February, 2005.     

A new look at the components of the petroleum system of the South Caspian Basin

Detailed knowledge of the petroleum systems of mature petroleum provinces is often lacking. This has often resulted from the early discovery of most of these provinces' reserves. The South Caspian basin represents one such province. The “modern” era of petroleum exploration in the South Caspian began more than 100 years ago. Even with this long history several aspects of the petroleum system have remained largely speculation. Among the key questions are:

• What is the primary hydrocarbon source for the region?

• Where and when has hydrocarbon generation taken place?

• Can exploration be extended beyond known stratigraphic and areal limits?

Recent integrated geologic and geochemical studies have attempted to answer these and other questions for the petroleum system of the South Caspian basin. These studies attempted to overcome prior problems associated with limited sample availability, severity of surface weathering, data quality and completeness. This study confirmed the Maykop Suite as the primary oil source, but restricted its stratigraphic distribution. Organic carbon content within the Maykop ranged upward to 14.28 wt.%, with hydrocarbon generation potentials (S₂) approaching 75 mg HC/g rock. Source rock deposition was cyclic and included both oil- and gas-prone episodes. Geochemically, the region's oils are highly variable as a result of their complex and variable migration and alteration histories rather than their derivation from multiple source rock units. The oils display similar molecular and isotopic compositions to the extracted Maykop samples confirming their genetic relationship. The range in carbon isotope values reflects secular changes within the Maykop Suite source. Unlike some earlier studies, this study showed that all of the oils were generated within the conventional “oil-window” (R_o≈0.9–1.0%). This places the source system at depths in excess of 5 km and emphasizes the role that vertical migration played in the development of the basin's hydrocarbon accumulations. There is evidence that migration was episodic, possibly related to punctuated generation or the opening of conduits through the activity of mud diapirs. Model results also suggest that the rapid Plio–Pleistocene subsidence and sedimentation were the primary controls on hydrocarbon generation.These and other geochemical investigations confirm the potential for the extension of the known petroleum system beyond its current stratigraphic and areal limits.     

Polarographic determination of vanadium,nickel, cobalt,and iron in petroleum residues

Conclusions It has been shown that it is possible to determine polarographically, using a dropping mercury electrode, the elements vanadium, nickel, cobalt, and iron in the form of their sulfosalicylic acid complexes in an ammonium buffer electrolyte.The method was used to determine these elements in the concentrations in which they are present in the mineral residues of petroleum and petroleum products.Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 11, pp. 52–54, November, 1969.     

Rheological evidence of structural phase transitions in asphaltene-containing petroleum fluids

The aim of this paper is to provide data on the rheological/structural properties of “synthetic oils,” composed of light hydrocarbons (toluene) and a heavy fraction, containing asphaltenes (vacuum residue, VR). Samples with asphaltene concentrations 20–85 g/l have been studied at temperatures 0–60 °C and shear rates up to 1500 s⁻¹. The non-Newtonian flow curves were approximated by the Bingham and the Herschel–Bulkley models to determine the apparent yield stress and the shear-rate exponent as functions of the asphaltene concentration and the temperature. Sharp variations of these parameters were attributed to formation/destruction of extended ordered structures in asphaltene colloid suspensions. Structural changes were observed in the temperature range 20–30 °C, particularly important for industrial processes of reservoir development and pipeline transportation. A molecular model of the observed macroscopic effects takes into account possible first-order structural phase transitions in the nanometer-size resin/asphaltene colloid microparticles.     

STRUCTURAL TYPES IN PETROLEUM ASPHALTENES AS DEDUCED FROM PYROLYSIS/GAS CHROMATOGRAPHY/MASS SPECTROMETRY

An integrated technique has been developed for the study of the thermal chemistry of petroleum fractions—particularly the asphaltenes. The procedure involves the integrated use of a pyroprobe/gas chroma-tographic/mass spectrometric technique which offers information about the structuraI-types and distribution within the volatile products from the thermal decomposition of asphaltenes. The technique offers itself as an attractive on-line analytical method for the study of structural types that occur in asphaltenes as well as a technique for studying the parameters that can influence asphaltene decomposition. The concept of deducing “average” structures of asphaltenes is briefly discussed in terms of the observance of the lower molecular weight species in the volatile products of the thermal decomposition.     

New commercial products with improved environmental properties

The necessity of replacing highly carcinogenic and highly toxic coal-tar oil used in Russian creosote plants as the basic protective antiseptic agent led to the development of a formula and technology for production of new protective materials based on less toxic and less carcinogenic petroleum cuts. The possibility of obtaining new petroleum protective material from delayed coking gasoils is demonstrated.Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 6, pp. 47–49, November– December, 2004     

Optimization of the composition of oil and gas condensate mixtures for primary refining

A simple method of calculating the optimum composition of oil and gas condensate feedstock with the easily determined physicochemical properties of its components and standardized performance properties of petroleum products is examined.Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 1, pp. 37 – 39, January – February, 2005.     

A new method for isolation of asphaltenes from petroleum and its heavy residues

A new method for the determination of the asphaltene content in petroleum and its heavy residues was developed that is based on the use as a solvent of carbon dioxide in a mixture with n-heptane or carbon dioxide at its supercritical parameters. The method is useful not only for the quantitative determination of asphaltenes in petroleum and petroleum products but also for the isolation of asphaltenes in amounts sufficient for investigation of their composition and properties.     

Water contamination and colloidal stability of motor oils

Water contamination of motor oils during storage and use in low-temperature conditions cause formation of deposits. These deposits, which consist of asphaltenes and additives, characterize the colloidal stability of the oils. A decrease in the concentration of additives worsens the performance properties of the motor oils. __________ Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 4, p. 33–34, July–August, 2006.