Increasing the Efficiency of the Autothermal Processing of Coal in a Fluidized Bed

The results of work on increasing the efficiency of heat energy production in standard boiler units using the «TERMOKOKS-KS» technology by intensifying the energy-technological processing of coal in a fluidized bed are presented. A significant increase in productivity has been established when removing small grades from coal and subsequent drying of coal, which makes it possible to reduce the cost of the obtained heat energy. The coarsening of the particles of the obtained browncoal coke with a decrease in the moisture content of the coal was revealed, which increases its transport characteristics. The range of temperatures of stable operation of the fluidized bed has been increased, due to which the product range of the «TERMOKOKS-KS» process has been expanded. The heat and material balances of the processes of combined production of heat energy and carbon-containing products are presented

Regulation of Cooling Mode of Thermoelectric Bloc

With the help of a computational model, the cooling modes of a block of a thermoelectric refrigeration unit designed for ship's provision and freezing chambers are studied. The computational model, based on the numerical solution of a system of nonlinear algebraic equations, takes into account the operating characteristics of a serial thermoelectric module and the thermal resistances of heat removal and supply devices. The dependences of the cooling power and the coefficient of performance of the block on the supply current of the thermoelectric modules are calculated. The analysis of the cooling modes of the thermoelectric block is carried out and recommendations for regulating the current strength depending on the current temperature conditions in the provision and freezing chambers are developed

Thermal Conducting Properties of Metal-fluoroplastic Material Determined by Tribological Method

The work is devoted to considering the possibility of using the Fourier law and the data of tribological tests for the approximate determination of the thermophysical characteristics of the sheet metal-fluoroplastic material on a steel substrate. The thermal conductivity coefficient of two different fluoroplastic materials was determined by tribological method using the temperature difference in the friction zone. It was shown that friction conditions change from viscoelastic to plastic

Hydraulic Calculations of Earthen Channels for Reconstruction

The problems in the design, operation, and reconstruction of earthen channels analyzed on the example of Mirishkor canal. The need for a new approach to the reconstruction have been defined using the results of field study and HEC-RAS modelling software. Recommendations are given for improving the hydraulic calculation of irrigation canals

Gold Leaching by Various Solutions, Alternative of Cyanide and Their Prospects in the Future

The article discusses four alternative cyanide substitutes for the recovery of gold from ores and concentrates. Cyanide has been the premier gold leach reagent for over 100 years due to its high recovery, low cost and reliability. However, environmental damage from improper management has led to widespread research aimed at identifying and developing less toxic leaching agents. The article discusses the most widely researched cyanide substitutes, but it is clear that none of them has yet made any significant incursion into the dominance of cyanide as the preferred reagent in the vast majority of gold mines around the world

Thermal Processing of Thermal Coal Under Pressure to Produce Semi-Coke and Thermal Energy

The process of thermal processing of brown coals of grades 1B and 2B under external overpressure of gases in the range of 0–4.0 MPa is investigated. The dependences of the main characteristics of the obtained products – semi-coke and combustible gas-on the pressure are established. The material and energy balances of the process of thermal processing of both coal grades are given

Influence of Chemically Modified Ultra-High Molecular Weight Polyethylene on the Properties of Butadiene Nitrile Rubber

For the manufacture of frost-resistant oil and petrol-resistant rubber products, one of the most widely used rubbers is nitrile-butadiene rubber (NBR) with a low acrylonitrile content of 17–20 %. However, the technical properties of its vulcanizates do not always meet all high performance requirements. Therefore, the study of the possibility of improving the technical characteristics of vulcanizates based on frost-resistant NBR is an urgent task. This paper presents the results of studying nitrile-butadiene rubber BNKS‑18AMN filled with ultra-high molecular weight polyethylene (UHMWPE). A feature of this work is the study of the possibility of increasing the technical properties of the obtained elastomeric composites by increasing the interaction between chemically inert UHMWPE and BNKS‑18AMN using the chemical modification of UHMWPE. The modification of UHMWPE was carried out by chemical etching in a solution of chromic acid for 3 and 20 hours. A complex of laboratory studies of the obtained samples was carried out. The influence of the duration of chemical etching of UHMWPE on the rheological and vulcanization properties has been studied on the analyzer of the processing of rubber. It is shown that the filling of UHMWPE into BNKS‑18AMN, in general, leads to an increase in the viscosity of the rubber compound. Chemical etching of UHMWPE leads to a decrease in the rate of vulcanization and the density of the three-dimensional spatial structure of the vulcanizate. The study of the physical and mechanical properties in tension, wear resistance during abrasion and swelling in standard hydrocarbon liquid for testing rubbers SZR‑3 showed that chemical etching of UHMWPE leads to a decrease in strength characteristics, but at the same time leads to an increase in resistance to abrasion and has no significant effect on swelling. The study of changes in the properties of samples after heat exposure showed that chemical etching of UHMWPE significantly reduces the resistance to thermal oxidative destruction in the presence of atmospheric oxygen, but does not affect the resistance to thermal aging in the SZR‑3 hydrocarbon environment

Thermodynamic and Chemical Analysis of Water-Coal Fuel Ignition and Combustion in Adiabatic Combustion Chamber

The article presents results of improvement of physicochemical model of coal-water fuel ignition and combustion processes, taking into account ash content and release of volatile substances of solid phase. In this case, model of ignition and combustion of two systems of atomized coal-water fuel: drops and pure coal particles is taken as a basis. As a result of the analysis, the influence of ash content of coal-water fuel on output of combustible gases and content of water vapor in furnace atmosphere was established. Based on comparison of the diffusion coefficients of gases and the calculated values of equilibrium constants of reaction in combustion zone, conclusion has been of the leading role of water vapor oxidation of carbon in vortex adiabatic furnace. Performed numerical calculations have shown that combustion process of the above inhomogeneous systems (droplets and particles) in an adiabatic furnace within a short time becomes identical. Concentrations of volatile substances, oxygen (O2) and carbon dioxide (CO2) in various sections of the furnace have been established

Efficiency Criteria for Thermal Insulation Structures of Glass Furnaces

The optimal operation of high temperature reactors such as glass furnaces requires many factors to be considered. These are, for example, the duration of the campaign, operating costs, heat losses, trouble-free operation of units and many others, presented in the article. The aim of this study is to synthesize an efficiency criterion for optimizing the heat-insulating construction of a glass-melting furnace (HICGF), as well as obtaining the optimal values of the efficiency criterion for HICGF, which for the furnace under study are about 3.8 billion rubles. In the course of the study, the phenomenological heuristic-evolutionary optimization method by G. E. Kanevets (PHEOM.GEK), which has a number of advantages over other evolutionary methods. As the main generalizing criterion, taking into account the most significant production (volume, cost of the produced glass mass) and financial (costs for the construction and operation of the HICGF, the monetary equivalent of heat losses) indicators, the maximum gross income for the furnace campaign was adopted, which differs from prototypes in that it allows to take into account most fully the peculiarities of the work of the insulated side fence of the glass furnace. Using the software complex created on the basis of PHEOM.GEK complex systems for the side fence of a glass-melting furnace, the optimal set (sequence of location and thickness) of thermal insulation materials HICGF was determined, which allow maximizing the furnace campaign with minimal heat losses. The reliability of the data obtained is achieved by the correct use of the theory of heat and mass transfer and PHEOM.GEK. An efficiency criterion is proposed, which, by solving an optimization problem, made it possible to determine the optimal HICGF. The solution of the optimization problem in conjunction with the calculation of the duration of the furnace campaign makes it possible to form recommendations for the development of optimal HICGFs in the construction of new and cold repair of existing glass furnaces by specialized institutes and industrial companies

Research of Operation of Predictive Controllers of Distributed Generation Plant in Power Supply System with Energy Storage

The article discusses the power supply system of an industrial enterprise, which included a turbine generator plant operating on the basis of a synchronous generator equipped with predictive voltage and rotor speed controllers, as well as a high-power electric energy storage device. A description of the models of this plant, predictive controllers and energy storage, as well as the results of modeling when the system goes into an isolated mode of operation are given. Simulation was performed in MATLAB environment using Simulink and SimPowerSystems packages. The purpose of the work was to study the behavior of the proposed predictive controllers during the transition of the power supply system to the island (isolated) mode. Based on the results of computer simulation, it was concluded that the use of predictive controllers improves the damping properties of the system. The use of an energy storage device that is automatically connected to the network when the voltage drops, allows to reduce the overvoltage at the terminals of the generator during its unloading, as well as to reduce the required mechanical power on the turbine shaft in comparison with a permanently connected device. Predictive controllers can be recommended to increase the stability of distributed generation plants when switching to an isolated mode. It is advisable to conduct further research in the direction of creating algorithms for coordinated operation of controllers