Effect of Asphaltenes on the Thermal Properties of Petroleum and Bitumen Emulsions

The thermal properties and characteristics of the molecular structure of petroleum and bitumen emulsions were investigated by viscometer and Rayleigh light scattering. The viscosity, structural properties, and character of the intermolecular interactions in the emulsions are determined by the temperature of formation of these media. Formation at critical temperatures close to 36 – 38°C initiates a structural phase transition that alters the size and activity of molecular aggregates of asphaltenes. These aggregates serve as binder material in three—dimensional supramolecular structures containing wax microcrystals. The long (up to several months) memory of the emulsions concerning the conditions of formation is due to the strength of the three—dimensional structures that contain not only hydrogen but also covalent bonds.     

“Selective” Hydrotreating of Catalytic Naphtha Cuts

To ensure a sulfur content on the level of 0.05–0.10 wt. % in catalytic naphthas, hydrotreating technology has been developed for hydrogenating primarily sulfur compounds and diolefin hydrocarbons. Monoolefinic hydrocarbons are converted to an insignificant degree, which preserves the high octane number of the naphtha obtained. The process is conducted at a pressure of 2–3 MPa, temperature of 250–350°C, and feedstock space velocity of 5–10 h^–1. The possibility of selective hydrotreating of mixed catalytic and thermal naphthas was demonstrated. The technology has been industrially tested with positive results.     

The “Iodine Number” of TS–1 Fuel. On Elimination of the Index from GOST 10227–86

It was shown that unsaturated hydrocarbons in concentrations characteristic of TS–1 fuel weakly affect sludging in this fuel but significantly increase the existent gum content, and the rejected standard based on this limits the concentration of unsaturated hydrocarbons in fuel to a much greater degree than the iodine number index. Scientifically substantiated recommendations are given for eliminating the iodine number index from GOST 10227–86 for TS–1 fuel.     

Possibilities of improving ejector pump characteristics

We describe a method of choosing an ejector pump for given operating conditions. Generalized dimensionless characteristics of ejector pumps are given for averaged loss coefficients and top-notch designs. We explore the possibility of decreasing the coefficient of head loss by improving the profile for the delivery of passive fluid to an ejector pump (use of stepped diffusers).__________Translated from Khimicheskoe i Neftegazovoe Mashinostroenie, No. 2, pp. 26–28, February, 2005.     

Sulfuric Acid Alkylation of Isobutane by Olefins. Experience in Operation of a Jet Mixing Reactor

Experience in operating a sulfuric–acid alkylation jet reactor of new design — with no mixers and heat–exchange bank and a process scheme that includes this reactor, a hydrocyclone, three–phase separator, and circulating centrifugal pumps are described. An additional quantity of feedstock is added to the jet reactor operating in tandem with a cascade reactor without addition of circulating isobutane. The concentration of high–octane components in the products of the reaction, i.e., the alkylate production volume, increases. The results of operating the jet reactor in incorporation of propylene feedstock from the cascade reactor to butylene alkylate are reported. The additional volume of propylene alkylate is up to 1/3 of the total output of the unit, distillation is improved, and the Motor Octane Number decreases insignificantly — by a maximum of 0.5 points.     

Activation of Carbon Adsorbents Based on Oil Binders

Carbon adsorbents fabricated from coal and oil binders acquire ionexchange properties (exchange capacity: up to 2.42 meq/g) under the effect of irradiation (dose: 5×10⁵ Gy) in 0.01 – 0.1 N propanol (isopropanol) solutions of NaOH. They are characterized by elevated adsorption power in extraction of arsenic from wastewaters.     

Refining of Straight‐Run Naphtha Cuts on Modified Zeolites

Straightrun crude oil of gas condensate naphtha cuts for use as components of motor fuels must be refined: to transform their lowoctane components – nparaffins – into highoctane compounds, while not decomposing isoparaffins if possible. A catalyst with high molecularsieve selectivity with respect to conversion of nparaffinic hydrocarbons and high catalytic stability is required for this. These requirements are satisfied by highsilica zeolites form the pentasil family [1 – 5].     

Removal of Aromatic Hydrocarbons from Reforming Naphtha. Combined Extraction — Extractive–Azeotropic Distillation Process

Separation of C6–C9 aromatic hydrocarbons from naphtha cut reformate by extraction with sulfolane followed by extractive/azeotropic distillation of the extract phase with sulfolane and ethanol. For mass ratios of sulfolane to feedstock of 1.6:1 and 0.28:1 in the stages of extraction and extractive–azeotropic distillation and a ratio of ethanol to feedstock of 0.032:1, raffinate was obtained with a yield of 65 wt. %, which satisfies the long–term environmental requirements for gasoline and benzene, toluene, and C8 and C9 aromatic hydrocarbons with a yield of 89, 77, 69, and 24 wt. %.     

Mathematical model for describing the process in the regenerator of a catalytic cracking unit 43–102

Conclusions Utilizing the mathematical model proposed, we have studied the effects which the initial coke content of the catalyst, the circulation rate, and the temperature at the regenerator top have on the regeneration in a 43–102 unit.A rise of the initial coke content (at unaltered values of the other parameters) considerably accelerates the warming-up process of the catalyst in the regenerator and shifts the hot spot into the lower sections of the regenerator. The removal of coke by burning may be incomplete both at high and at too low values of the initial coke content.Acceleration of the circulation rate (at unaltered values of the other parameter) has only a slight effect on the temperature of the hot spot in the regenerator. The hot spot is shifted in the direction of circulation of the current, and the regeneration does not attain the specified depth at high circulation rates.The temperature at the regenerator top has a strong effect on the temperature profile. A lowering of the temperature at the regenerator top results in a drop of the temperature in the hot spot of the reactor and in incomplete burning of the coke.Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 6, pp. 37–40, June, 1969.     

Optimization of the Composition of Binary Alternative Diesel Fuel

Alternative products — rapeseed, sunflower, soy, and other vegetable oils and derivatives — are increasingly being used as diesel fuel. Biodiesel fuel — vegetable oil fatty acid methyl esters — have 8–10% higher density and two times higher kinematic viscosity than petroleum diesel fuel. This is reflected in operation in the diesel cylinder and the integral environmental and economic characteristics. The composition of the alternative fuel can be optimized by mixing biodiesel with light crude oil cuts. The fractional distillation curves are given for Biodiesel, gas condensate, diesel fuel (summer and winter), and the proposed binary alternative fuel.     

Rapid determination of fractional composition of C10-C16 and C17-C20 synthetic fatty acid fractions in the “Tsvet-1” chromatograph

Conclusions A rapid method has been developed for the chromatographic determination of the fractional composition of C₁₀-C₁₆ and C₁₇-C₂₀ synthetic fatty acid fractions in the form of the methyl esters, using the Tsvet-1 chromatograph at a single temperature. The time required for analysis is 55–60 min.Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 4, pp. 51–53, April, 1972.     

Gas chromatographic method of identifying components of complex mixtures

Conclusions The new functions and _t are proposed which enable the components of complex mixtures separated chromatographically to be identified with great accuracy.Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 1, pp. 59–62, January, 1967.     

Paving Asphalt Production Technologies. Analysis of Effectiveness

The possibilities of using previously approved new process solutions in production of oxidized paving asphalts are examined based on the proceedings of the interindustry conference Problems in Production and Use of Petroleum Asphalts and Asphalt-based Composites (Saratov-2000) and recent publications.__________Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 2, pp. 29 – 34, March – April, 2005.     

Naphtha Cut Hydrotreating Units at Yaroslavnefteorgsintez Company

A naphtha cut hydrotreating unit with output of 750,000 tons/year was started up in October 2003 at Slavneft'—Yaroslavnefteorgsintez OJSC. The unit was turnkey designed and built by Kedr–89 SIC on order of YaRVAZ CJSC — a subsidiary of Slavneft' OGC.     

Production of low-pour diesel fuels by hydroisomerization of middle distillates from eastern medium-sulfur crudes

Summary Processes have been developed for catalytic hydrotreating and isomerization of n-paraffins to produce wintergrade diesel fuels from middle distillates.In the single-stage process on sulfur-resistant hydrotreating catalysts promoted with halogens, thorough drying of the feedstock and the hydrogen-rich recycle gas is required, along with promotion of the catalyst with the halogen and protection of the equipment against hydrogen halide corrosion.The yield of winter-grade diesel fuel conforming to specification GOST 305-62 (solid point –35C, cloud point –25C) is 85% by weight.In the two-stage process, the first stage is a thorough hydrotreating operation, the second stage hydroisomerization of the n-paraffins. The yield of winter-grade diesel fuel conforming to the requirements of GOST 4749-49 (solid point –45C, cloud point –35C) is 70% by weight. Also formed in the process is some 21–24% naphtha cut with a clear octane number of 76 by the motor method.Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 9, pp. 22–25, September, 1973.     

Laboratory Appraisal of Slime Formation in Motor Oils

Water accumulated in motor oils in the process of use exercises a profound effect on the fundamental properties of the oils: lubrication efficiency of the oils changes and their tendency for sliming increases. It is commonly believed that precursors of slime are products of nitration or sulfonation of aromatic components of fuel fractions. However, Russian scientists proposed a different concept of the mechanism of low–temperature sediment formation (sliming): products of thermolysis of heavy aromatic hydrocarbons, viz., asphaltenes, which possess paramagnetic properties, play the decisive role in this process. Indeed, these products, by reacting with water, form a soft precipitate.     

Agroindustrial Wastes as Feedstock for Production of Oils

The prospects for rational utilization of secondary feedstock resources – different plant wastes – in refineries were demonstrated. In exhaustive processing of these wastes, it is possible to obtain quality vegetable oils for food and technical purposes. The environmental and technological aspects of the production and use of such oils are examined. The increased role of lubricants and other products based on biospherecompatible vegetable oils is emphasized.     

Pour Depressants for Middle-Distillate Fuels. A Comparative Analysis of Effectiveness

Copolymers of ethylene and vinyl acetate, propylene, vinyl acetate and carboxylic acid esters, and methyl methacrylate with different number–average molecular weights and molecular–weight distribution (MWD) were investigated as pour depressants for middle–distillate winter–grade fuels. The specific character of the effect of the additives on fuels with different n–paraffin content and MWD is established. The effectiveness of the additives is determined by the presence of a gently sloping high–molecular–weight (C₂₆₊) tail on the MWD curve of the n–paraffins in the base fuel. The optimum concentrations of pour depressants for middle–distillate fuels manufactured at YuKOS Oil Co. refineries are determined.     

Stability of Aqueous Microemulsions In Motor Fuels

The effect of additives — surfactants (SF) — on the water–separating properties of jet fuels. These additives significantly worsen thefuel–water reaction index. Methods of fuel flooding simulating the conditions of formation of water–fuel microemulsions during storage, shipment, and use are developed. Data on the effect of the nature of the fuel on the settling rate of microemulsions are reported. Water–fuel microemulsions form when temperature fluctuations are stable for more than 100 h, which favors formation of aqueous sludges in aircraft tanks.     

Separation of Aromatic Hydrocarbons from Reformate. Combined Extraction Fractionation–Eextraction

In separation of benzene, toluene, and xylenes from reformate by extractive fractionation, the solvent, consisting of N–methylpyrrolidone and sulfolane (70:30) is more effective than each of the components separately. C6–C8 aromatic hydrocarbons are separated with a yield of 99.8 wt. % by extraction fractionation and subsequent extraction of benzene residues from distillate with sulfolane:N–methylpyrrolidone solvent (90:10 wt.) with a total mass ratio to the feedstock of 2.8:1. Key words: reforming catalyzate, aromatic hydrocarbons, extraction, extraction fractionation, N–methylpyrrolidone, sulfolane.