Information
Registration Number
0219U005348,
Title
Development of scientific-technical fundamentals of energy transformations of carbonaceours raw materials of various degrees of metamorphism and its division dehydration and increase the efficiency and reliability of power
Head
Voloshin Alex John, Доктор технічних наук
Registration Date
11-09-2019
Organization
The Polyakov Institute of geotechnical mechanics of NAS of Ukraine
Description
The object of research - vibration systems with limiters of displacement and the inertia exciters of oscillations of a limited power; processes of motion and energy transformation of carbonaceous materials in plasma reactors; rationalized parameters of the small thermal energy complexes for utilization of low-grade heat in contact heat exchangers when using perspective ways of their intensification. The purpose of work - establishing of correlations and parameters of polyfrequency vibrating screen with limited power of the vibration exciter; establishing of correlations of the energy transformation of carbonaceous materials in a plasma reactor and electromagnetic fields of the arc plasma; elaboration of the methods of the energy consumption reducing of the transformation process and determination of the rationalized parameters for the reactor; elaboration of the recommendations concerning selection of the parameters of the small thermal energy complexes for utilization of low-grade heat in contact heat and mass exchangers when using perspective ways of their intensification. Research methods - theoretical (analytical and numerical analysis) and experimental methods under laboratory and industrial conditions. Study of the correlations of the dynamic processes of the polyfrequency vibrating screen with the vibration exciter of limited power allowed to establish that at start-up for the screen passing through its eigenfrequency of oscillations on the elastic bearings and reaching of vibroimpact modes, less than one order of magnitude power of the asynchronous motor is needed than for the modes of nonimpact oscillations. Along with an increasing in the drive power and the exciting effort of the vibroexcitator, the regions of the existence of vibroimpact modes of oscillations are increased. In addition to the power, the excitement force of the inertial vibroexcitor of the oscillations affects the reaching of the screen for stationary vibroimpact modes. The spectral density of these oscillations depends on the gaps in unilateral elastic bearings and the asymmetry of the screen parameters. This allows to equip the screens by electric motors of reasonable power, which contributes to the reduction of electric energy consumption and improves the conditions of start-up when screen passing through its eigenfrequency of oscillations on the elastic bearings and reaching vibroimpact modes, which are most effective for the classification of pulverized coal during its preparing for combustion in boilers of TPP. The mathematical model of motion and heat and mass transfer of a turbulent swirling stream with coal particles of different degree of metamorphosis in a plasma reactor, which for the first time takes into account chemical reactions with volatiles, nitrogen, sulfur, and allows to establish new correlations of thermochemical processes in a plasma aerodynamic reactor for the preparation of coal fuel prior to combustion in boilers of the TPP and determine its rationalized parameters, modes of operation, providing coal combustion with volatile content from 3 to 40% without lighting by oil and gas is developed. The estimation of ways and technical means of intensification of heat and mass transfer in the processes of plasma-chemical transformations of carbonaceous mediums is made and the influence of heat exchange on the heating of a coal particle in the reaction chamber at a gas temperature Tg <2000 K is found. The study of the process of high-temperature (Tg ? 2000 K) transformations of carbonaceous media in a plasma-arc reactor chamber was carried out and the influence of thermal and kinetic parameters on the time of complete conversion of the coal particles was determined. The expediency of the temperature increasing of gases in a reactor of a compatible type up to Tg = 3000 K, which determines the minimum value of the time of carbon conversion with the combined effect of convective and radiation heat exchange, is proved. The basic geometric, thermal and regime parameters of the steam-plasma module with the power of 160 kW are determined. The design of the steam-plasma module has been developed and tested under the laboratory conditions. Formulated and solved a number of problems on the distribution of substances in water dissolving pore walls, which are relevant in case of presence of thin baffles in the porous medium that block definite porous sections. The rationalized parameters of the operating process in a fluidized bed reactor are determined based on the equations of thermal and material balances, the burnout and gasification of carbon, the aerodynamics of a concentrated dispersed system as well as the heat exchange between particles and a layer of a two-phase medium. Accordingly to the improved methodology of the calculation for the regime-constructive parameters of contact heat exchangers for the utilization of the heat of flue gases, a range of values of the dispersed phase parameters is established, for which the heat transfer in the unit is most effectively provided, the target parameters for designing and the sequence of calculations of their rational values are determined. In the calculations of the thermal-hydraulic efficiency of porous direct-flow steam generators under the boundary conditions of the third kind, it was first obtained that under transitional flow regime and the same channel diameters it is possible to achieve a significant reduction in the length (up to several dozen times) of a porous direct-flow steam generator compared to a smooth-wall, straight-flow steam generator. The recommendations, that consist of optimization and selection of the parameters of a new technical solution for the utilization of waste heat of gas-piston units that burn coalmine methane in small thermal power complexes, are developed. The technical solution involves transformation of the heat of the engine cooling system and flue gases into electric energy by means of a two-circuit thermal power unit with different working mediums in the circuits. Application of the proposed energy saving technologies for the utilization of low-grade heat on the basis of contact heat exchangers will increase the generation of electricity by 15 - 20 % and bring the total efficiency of technological unitss for electricity generation up to 50 %. The results of the work allow to create a more complete theory and methods for calculating the processes and units for separation, dehydration, thermochemical transformation and utilization of heat during energy conversion of a carbonaceous medium. The results of research can be used for the design of equipment in the thermal energy and chemical industries. Key words: vibroimpact systems, vibration exciter, carbonaceous materials, gasification, heat and mass exchange, plasma reactor, low-grade heat, capillary-porous body, fluidized bed