


Vol 53, No 3-4 (2017)
- Year: 2017
- Articles: 24
- URL: https://journal-vniispk.ru/0009-2355/issue/view/14636
Research, Design, Calculations, and Operating Experience
Comparative Analysis of Stressed State in Torispherical and Elliptical Heads of Pressure Vessels
Abstract
Analysis of stressed state of torispherical and elliptical heads of pressure vessels having branch pipe on the head made it possible to disclose patterns of meridional and circumferential stress distribution in the heads under internal pressure, determine the area of maximum stresses, and ascertain the influence of nondimensional geometric parameters of vessels with heads with a branch pipe on the maximum compressive membrane circumferential stresses. The investigations were performed using finite-element method in a mixed variational formulation and a specially developed SAIS computer program.



Calculation of Efficiency of a Continuous Sedimentation Centrifuge with Scroll Sediment Discharge
Abstract
Separation of a liquid + solid suspension in a scroll centrifuge rotor is simulated using a model of slow relative motion of an isolated small-diameter spherical particle in a swirling flow of an incompressible viscous liquid circulating between two rotating coaxial cylinders. The key efficiency parameters of the machine in terms of separation fineness and suspension clarification factor were substantiated, taking account of the kinetic characteristics of the solid phase sedimentation process in the flow in a criterial form. The results of numerical experiment on simulation of spherical powdery substance separation process are presented in dimensional terms and criterial parameters.



Article



Development of Hybrid Equipment for Well Drilling and Hydrocarbon Production from Offshore Deposits
Abstract
Efficient reservoir pressure utilization is a promising research direction for reducing energy and financial costs of hydrocarbon production from offshore deposits. A design and a description of the principle of operation of a turbine power block having a dynamic separator are given. The developed mathematical models and computer simulation confirmed the potential of this research direction.



Optimization of Construction of the Mixing Chamber with a Multiple Jets Inlet of a Heat Carrier in Pneumatic Conveying Dryers for Potassium Chloride
Abstract
Results are presented for physical and mathematical modeling of the operation of different mixing chambers with a multiple jets inlet of a heat carrier in pneumatic conveying driers for potassium chloride. The influence of the shape of the chamber and the spacing of holes for heat carrier input on temperature inhomogeneity of the resulting mixture, particulates temperature and contact intensity of particulates with the chamber walls are considered. A mixing chamber design providing minimal contact intensity and sticking of the dryable particulates with the walls is recommended.



Energy and Resource Efficiency in Industrial Systems for Production and Use of High-Purity Hydrogen
Abstract
The feasibility of applying energy- and resource-saving technologies in the modernization of the existing metallurgical industries associated with the production and use of high-purity hydrogen is clearly illustrated on a few practical examples. One way of reducing energy consumption is by using natural gas as a feedstock for the production of high-purity hydrogen instead of using the electrolysis method. Another way of reducing energy consumption in the production of high-purity hydrogen is by developing high-purity hydrogen reuse systems.



Hydrodynamic Calculation of Bearing-Seal Assemblies of Centrifugal Pump with Self-Adjusting Rotor
Abstract
Hydrodynamic forces in slot seals of centrifugal pumps play a leading role in stabilization of vibrational activity of rotor pumps. It enables one to assess afresh the role of contactless seals of flow passages, such as bearing-seal assemblies of centrifugal pumps. The pump rotor adjusts automatically in symmetric slot seals under the action of hydrodynamic forces and moments. The proposed calculation procedure realizes a new design approach to creation of elements of flow passage of centrifugal pump having slot bearing-seal couples.



Effect of Ball Valve Component Materials on Wear
Abstract
Features of the wear of mating parts of ball valves made of heat-resistant cast alloy ZhS-6U and cermet based on uncoated titanium carbide TiC–ZhS6U and with wear-resistant TiN and Zr–Ti–N–C coatings are studied. It is established that wear-resistant coatings based on cermets prevent the emergence of hard TiC inclusions at the friction surface thereby reducing friction pair component abrasive and mechanical wear and decreasing the overall degree of ball valve wear.



Gland Seal with Soft Packing of Trapezoidal Cross Section and Inside Seating of the Pressure Flange
Abstract
Results of an analysis of three types of gland seals with soft packing and inside seating of the pressure flange are presented. The packing had a cylindrical or trapezoidal cross section with standard or tapered o-ring gaskets. It was shown that gland seals with packing o-ring gaskets that were pressed beforehand in special matrices or directly in the gland body were most effective.



Mathematical Model for the Motion of Precipitated Dust Particles in a High-Efficiency Cyclone Dust Collector for Explosion-Hazardous Production
Abstract
A mathematical model of the motion of a dust particle on the surface of the cylindrical body and conical insert of a cyclone dust collector was developed taking into account factors contributing to its separation from the surface. Structural and operational parameters of the device were determined.



Heat Transfer in Turbulent Channel Flows of Polyatomic Gases with Variable Physical Properties
Abstract
Universal relationships for boundary layer characteristics are used to derive an equation for the Nusselt number, which describes heat transfer in turbulent gas flows in straight and smooth channels. The equation contains the structural parameter that takes account of the influence of the variability of physical properties of the heat carrier on heat transfer. Analysis of quasi-thermal flow conditions showed that the derived equation agrees well with the Petukhov and Kirillov formula. The influence of the temperature factor T w /T av in the 0.2–5 variation range on heat transfer of the gas flows is analyzed. The results of calculations of heat transfer of air flow under conditions of variability of its physical properties are compared with theoretical and experimental data of other authors. It was found that, apart from the temperature factor, the Re number and atomicity of the gas affect the Nu/Nu0 ratio (Nu0 corresponds to constant properties). The nature of these influences differs for heating and cooling of the gas flow. For gases with atomicity higher than 8, heat transfer becomes self-similar with respect to the number of atoms in the gas molecule.



Modeling of a Double-Pipe Enclosed Heat Exchanger with Temperature Jumps of Heat Carriers at the Heat-Exchanger Inlet
Abstract
Basic parameters of a double-pipe enclosed heat exchanger were calculated for four possible cases of ideal heat-carrier flow structures. It was shown that the heat-transfer coefficient depended little on the ideal heat-carrier flow structures although the heat-transfer driving force and specific thermal power changed by a factor of three. Technological and geometrical parameters from a typical calculation of a double-pipe enclosed heat exchanger with plug flow of both heat carriers without and with temperature jumps at the heat-exchanger inlet were compared.



Heat-Exchanger Efficiency Evaluation Based on Real-Time Determination of Exergy Efficiency as a Control Criterion
Abstract
An approach for evaluating heat-exchanger operating efficiency using the calculated exergy efficiency (EE) that allows heat-exchanger system elements with low heat-transfer efficiency to be located and their maintenance (cleaning) to be managed according to their condition was proposed. Measurements required for the EE calculation were recorded automatically from the Automatic Process Control System databases of the application. Real-time mathematical modeling of the current mode of the facility using a computer training complex provided additional data.



Selection of Oxidation Catalyst in a Fluidized-Bed Reactor
Abstract
Oxidation catalysts, e.g., those for biomass combustion in a fluidized bed (olivine sand and catalyst ShchKZ-1), were compared. Samples consisting of straw powder, straw powder and uncalcined olivine sand, straw powder and calcined olivine sand, and straw powder and crushed catalyst ShchKZ-1 were prepared. The calcined olivine sand and catalyst ShchKZ-1 had practically the same influence on the sample mass loss and heat generation from the straw by heating.



Investigation of the Hydrodynamic Flow Pattern in Tubular Membrane Devices
Abstract
The present work examines the hydrodynamic flow pattern in an industrial tubular baromembrane device on the example of commercially available membrane elements at pressures of 1.0–4.0 MPa. Experimental response curves and dependence curves of the longitudinal mixing coefficient were obtained as a function of the solution flow rate and the pressure in the membrane module. Based on this information, the criterial equation for calculating the longitudinal mixing coefficient was obtained. Numerical values of empirical coefficients are given, which can theoretically be used to calculate the longitudinal mixing coefficients as well as to predict the values for similar constructions of baromembrane systems operating at high transmembrane pressures.



Thermal Conductivity of External Contaminants of Air-Cooled Heat Exchangers
Abstract
The results of experimental studies of thermal conductivity of the dominant types of external contaminants of air coolers are given. Reed down, peat litter, leaves, sand, pine needles, and ash were investigated, as well as mixtures: sand with ash, sand with reed down, peat litter with leaves. The results are presented as the dependence of thermal conductivity on the density of contaminants. A linear approximation generalizing the found dependences is recommended. It is shown that thermal conductivity is significantly dependent on the pollutant porosity.



Deceleration and Reversal in the Direction of Motion of Water Droplets in a Counterflow of Combustion Products of Flammable Liquids
Abstract
This paper presents the results of experimental investigations of deceleration and entrainment OF water droplets moving in a counterflow of high-temperature combustion products of liquid fuels and flammable liquids. High-speed video cameras and panoramic optical methods (Particle Image Velocimetry, Stereoscopic Particle Image Velocimetry, Particle Tracking Velocimetry, Shadow Photography) were applied to record the parameters of movement and evaporation of water droplet flows. To generate the combustion products with a high controlled temperature (400–1900 K), some typical oils, gasoline, kerosene, acetone, and industrial ethanol were used. This paper generalizes the results of investigations by establishing for droplets and gases the ranges of Reynolds number variation within which complete droplet deceleration and removal by drift is possible.



Composition of Synthesis Gas Produced by Intraformation Electrophysical Gasification of Coals at Different Heating Rates
Abstract
Electrophysical intraformational gasification of coals from the Egozovo-Krasnoyarsk, Krasnogorsk, and Balakhta deposits was investigated. The quantitative composition of the synthesis gas was determined. Its heats of combustion at various heating rates were calculated. It was found that the concentrations of H2 and CO2 in the obtained synthesis gas decreased whereas that of CO increased if the heating rate was accelerated. The results showed that accelerating the heating rate increased slightly the heat of combustion because the decreased H2 and CH4 concentrations were compensated by the increased CO concentration.



Investigation of Heat Exchange During Movement in a Horizontal Tube of an Aqueous Propylene-Glycol Ice Slurry
Abstract
A test method for investigating the heat-transfer coefficient as a function of the concentration of ice crystals in an ice slurry, the ice slurry flow rate in a tube, and the tube heat-flow density was presented. The experimental results were given. Comparative tests were carried out with a single-phase aqueous propylene glycol solution of the same initial density as the liquid from which the ice slurry was prepared.






Design of Stationary Seals for Underwater Oil Production Equipment
Abstract
Operating conditions of stationary rubber seals for sealing underwater oil production equipment as well as criteria and methods of ensuring working capacity of these seals at the design and numerical analysis stage are studied. Examples of the designed seals working in underwater oil production equipment are given.



Industrial Ecology
Treatment of Industrial Dust-Air Flows in Centrifugal-Inertial Apparatuses
Abstract
The urgency of developing highly efficient dust collectors for fine dust was demonstrated. An experimental centrifugal-inertial dust collector was constructed. Experimental results showed that dust could be classified by fractions in the developed dust collector. The impacts on the biosphere and human health of fine dust in industrial wastes and air emissions were examined.



Economics
Technoeconomic Analysis of Prospects of Use of Organic Coal-Water Fuels of Various Component Compositions
Abstract
A technoeconomic analysis of the suitability of using suspended organic coal-water fuels (OCWF) of various component compositions was performed to determine the parameters that illustrate the priority of individual components and of the suspensions as a whole from the point of cost, ignition delay time, minimally adequate oxidizer temperature, combustion duration, and combustion heat of OCWF. The obtained data can be used to optimize the choice of the type and concentration of OCWF components that ensure efficient utilization of this type of fuel. An analysis was made of the feasibility of expanding the raw materials base for development of OCWF combustion technology.



Information
Technology and Economics of Recycling Oil-Tank Sediments
Abstract
The structures and properties of oil-tank sediments were investigated. It was shown that they could be used as a boiler-fuel component. A recycling method for oil-tank sediments was developed. An environmental and economic assessment of its implementation effectiveness was presented.


