Том 53, № 1 (2017)

Antiwear properties of fuels for airbreathing jet engines (AJE) based on three types of rapeseed-oil biocomponents and their blends are studied experimentally. It is shown that the biocomponents are much better lubricants than conventional petroleum fuels for AJE. The studies found that additionof biocomponents to aviation fuel strengthens boundary layers and thereby improves the antiwear properties of the fuel blends. It is demonstrated that additional modification of the biocomponents enhances their lubricating capacity with respect to standard rapeseed-oil components.

Cyclopentadiene is alkylated by C₆–C₁₀ monohydric alcohols in the presence of an alkali catalyst. The effects of the cyclopentadiene/alcohol mole ratio, reaction time, and reaction temperature on the yields of normal dialkylpentadienes were elucidated. The hydrogenation of dioctylcyclopentadieneyields the corresponding highly viscous dialkylcyclopentane which can be used as a synthetic oil or additive to mineral oils.

The foaming properties of lubricating oils for aviation gas-turbine engines were studied experimentally. The dependences of the aviation oil foamability on the air flow and temperature were found. Addenda to the standard method of GOST 21058-75 for more accurate determination of aviation oil foamability were presented. It was shown that the oil-system operating characteristics changed if the oil foaming properties changed.

A mathematical model of the process of low-temperature carbonization of sulfur-bearing oil shales in a fluidized-bed retort, which takes account of the characteristics of hydrodynamics and heat exchange in the thermal shale decomposition process as well as the kinetics of thermal degradation of the organic matter, is developed. A block diagram of the calculation algorithm and the results of numerical experiment based on the developed mathematical model are presented. It is shown that the properties of the sulfur-bearing shale and the conditions of the low-temperature carbonization process affect the parameters of the fluidized-bed retort.

Theoretical and experimental studies of the change of diffusion coefficient in porous media are reported. Mathematical equations were derived for calculating the diffusion coefficient in oil and gas phases. Experiments were conducted by measuring the pressure decline in both a PVT-cell and a sample of actual core. The medium porosity was found to have a significant effect on the system pressure decline. The diffusion coefficient in the PVT-cell was two orders of magnitude greater than that in the core. The diffusion coefficient was studied as a function of rock permeability and porosity. It was found that the porosity was the main factor affecting the diffusion coefficient whereas the permeability could be neglected.

Acid-fracture conductivity has a major impact on acid-fracturing effects. In this paper, influences of acid concentration, temperature, and closure-stress loading time on conductivity under different acid-fluid systems have been researched based on experimental analysis for deep limy dolomite reservoirs. The measured conductivity showed high correlation and specific changing patterns with the above factors. Quantified relationships and equations between the conductivity and these factors were suggested in this paper. Additionally, a strong acid-etching effect caused by crosslinked acid and diverting acid has been observed during the tests. This could lead to high conductivity as well as broken rocks due to pressing with high-concentration acid. In this study, a 50-hour long-term conductivity test has been designed under the closure stress of 60 MPa which was closest to the actual reservoir conditions. The results showed that conductivity retention rate for each test group is less than 40%. By establishing assessment criteria of long-term and short-term conductivity based on the conductivity retention rate, linear relationships with high correlation and quantified equations of the conductivity retention rate in the same acid-rock reaction system could be obtained.

General principles of polymer flooding technology were elucidated based on existing profile-control studies. The current situation and problems of filtration profile-control technology were analyzed. Oil reservoir permeability was studied as a function of crosslinked polymer concentration. Several recommendations for optimal implementation were given.

A kinetic analysis is presented for a proposed scheme for sulfone production by the oxidation of petroleum sulfoxides by the action of hydrogen peroxide using a molybdenum (VI) oxide catalyst. Theoretical calculations and experimental data indicate that the sulfone concentration in the initial stages of the reaction depends linearly on the square of the elapsed reaction time. The effective activation energy of this reaction was found to be E_act = (31 ± 7) kJ/mole.

The reaction of transesterification of rapeseed oil in ethanol under supercritical fluid conditions in the 320-380 ϵC temperature range, under 30 MPa pressure, for ethyl alcohol to rapeseed oil molar ratios of (6-20):1 was studied experimentally. Dependencies of kinematic viscosity of the reaction product on the temperature, molar ratio of the starting reagents, and duration of reaction implementation were obtained. A correlative dependence that allows calculation of the content of ethyl esters of fatty acids in the transesterification product is proposed using experimental data on the kinematic viscosity values of the reaction product.

The absorption capacity of oily sludge pyrolysis residue was utilized to prepare oxygen-releasing composites for groundwater remediation. The physical properties of the oily sludge pyrolysis residue were specific surface area of 13.936 m²/g and main pore size on the order of nanometers. The pyrolysis residue was nontoxic and would not cause secondary contamination of groundwater. The rate of mass loss of calcium peroxide and the oxygen release rate in water were analyzed. An oxygen-releasing composite containing 35% calcium peroxide, 15% oily sludge pyrolysis residue, 30% fluviatile sand, 10% calcium-based bentonite soil, and 10% deionized water was proposed. Addition of oily sludge to the composite plugged some of the oxygen-releasing surface and slowed the rate of oxygen release. Continuous precipitation of CaCO₃ on the surface and in the pores of the composite also reduced the initial oxygen release rate and slowed the overall oxygen release rate.

The microstructure of the Wangfu volcanic reservoir and the predicted permeability reduction of this reservoir are investigated. It is found that water block (strata permeability reduction due to the penetration of water into the pore space) and fracturing fluid residue are the main causes of reduced deposit gas permeability. A subsuite of this reservoir, Quan-1, is sensitive to water whereas the Huoshiling and Shahezi formations are sensitive to acids. Therefore, an acidic fracturing fluid should be used in the first instance, and fluid with a low concentration of guar gum and minimal acid content – in the second. However, fracturing fluids with anionic surfactants should be used to solve the water-block problem in all three deposits, thereby increasing process efficiency.