Vol 53, No 7-8 (2017)

A theoretical model that describes the internal recycled particles separation process in suspended-layer vortex granulators (SLVG) with a height-variable cross-sectional area is presented. Relationships are derived to determine the recycled particles circulation time in SLVG with a specified configuration. The calculated results are confirmed by experimental studies on an SLVG prototype. The results of the analytical solution of the equations of the mathematical model can be used to design SLVG with an internal recycled particles circulation, which can be organized in various ways, depending on the need for simple recirculation or the presence of additional recycled particles thermal treatment stage during recirculation.

A design of a jet-film contact device developed for increasing the uniformity of liquid and gas phase distribution and enhancing mass transfer efficiency is described. The influence of the width of the drain cup on the mass transfer efficiency and hydraulic resistance is analyzed.

A mathematical model of the dynamics of chemical-engineering processes occurring in a stationary catalyst layer is proposed using industrial hydrofining of motor fuels as an example. The influence of the boundary layer between the gas and liquid phases of disperse filtration flow is considered by means of empirical approximating formulas. Results of a computational experiment using the aforementioned model comprising a system of differential equations in partial derivatives are presented and demonstrate the efficiency of artificially generated oscillatory control modes.

Theoretical and experimental studies of the working processes of slow-speed long-stroke piston compressor stages were performed. The obtained results indicate the possibility of compression of gases in such stages to medium pressures. The investigated stages, as the studies showed, had improved vibration and noise characteristics in comparison with the existing piston stages and can be one of the directions for improving piston compressor units.

Questions are considered for improving the reliability and wear resistance of cylinder-piston groups by adding antiwear additives to lubricating oil composition. Tribological studies are conducted for a new additive based on molybdenum diselenide that surpasses basic lubricating oil and also some other antiwear additives with respect to reducing wear of CPG materials.

The basic metrological characteristics of a reflection vacuummeter are analyzed on the basis of mathematical modeling. It is shown that the device is able to measure rarefaction with a high degree of precision even with significant oscillations in the temperature of the measurement fluid. Directions for further improvement in the device are proposed.

A novel design of an axial (self-centering) blowout prevention well-head seal that eliminates a number of the drawbacks in the wellhead equipment which is used today and whicuh possesses high services qualities, reliability indicators, and service life is proposed. The design is protected by Russian Patent No. 2573887.

A jet-film contact device was developed, and the principle of its operation is described. The results of studies on the effectiveness of the contact stage for different ratios of the liquid and vapor phases are presented based on the example of rectification of ethylbenzene–styrene mixture. The design parameters that affect the efficiency of the device are considered. The efficiency of implementing the contact device in mass transfer systems is discussed.

The effect of electric field frequency on the processes of destruction of water-oil emulsions in electric dehydrators is investigated. It is shown that the existing theoretical concepts regarding the processes of deformation, destruction, coagulation, and coalescence of droplets, and data available in the literature should be considered for three characteristic cases of an electric field being applied to the emulsion: a constant electric field; an alternating electric field with a frequency below the critical value; an alternating electric field with a frequency above the critical value. It is concluded that the effect of electric field frequency on the process of destruction of industrial water-oil emulsions in electric dehydrators is most pronounced under the influence of an alternating electric field with a frequency below the critical value in the working zone of the electric dehydrator, which has the shape of a confuser or a channel with a constant cross section.

Formulas for determining the required tightening force of the threaded elements of joints that experience particular changes in the course of use, such as variable loads, variations in the temperature of the working medium, and relaxation of the stresses in individual elements of the joint, are presented. An estimation of the length of the safe operation period of the joint until its next inspection is presented.

Results are presented for research in the development of new grades of corrosion-resistant steels for a bimetal cladding layer prepared by electroslag surfacing technology. It is shown that steel of transition martensiticaustenitic class may surpass martensitic steels both with respect to reliability characteristics and wear resistance. In this case, these steels have a more economic alloying system, and correspondingly low cost compared with austenitic chromium-nickel steels. Based on thermodynamic modeling of regions for phase existence optimum steel alloying systems are determined for new grades as a bimetal cladding layer.

Comprehensive utilization of spent sulfuric acid from petrochemical industries and Mg–Zn chemical current sources is discussed. A method for their complex processing that can produce Mg and Zn oxides as products is proposed.

The technology of applied systems analysis is proposed and subjected to practical testing in an analysis of damaged load-bearing structures of process equipment. The technology is based on a systematization of problem situations in terms of the nature and degree of damage corresponding to the statement of the problem and application of an expanded algorithm for the solution of these situations. Practical testing of the technology is illustrated by examples of damage to a tank, pressure vessel, and receiver.

Corrosion resistance of low-alloy steels 20-KSKh, 07GBK, 06GBF, 13FKhA, 09GSF, and 20 with different overall contents of corrosion-active nonmetallic inclusions (CANI) in process media for preparation and drying moist casing-head gas is studied. A study in a model medium simulating seam water of the Khar’yagin deposit, and in a moist hydrogen sulfide atmosphere for ten days shows that a reduction in CANI reduces the corrosion rate of low-alloy steels in a model medium compared with steel St20 by about a factor of two. In a moist hydrogen sulfide atmosphere after testing a steel 20 surface is coated with a uniform layer of corrosion products; in low-alloy steels, corrosion damage occupies 1–7% of the overall area. The results obtained agree with the role of CANI determined previously in developing overall and local corrosion.