Simeiko K. Scientific and technological bases of high-temperature processes in the electrothermal fluidized bed.

The dissertation is aimed at solving an important scientific and technical problem of development of scientific and technological bases of high - temperature (600… 3000 ° C) chemical processes in an electrothermal fluidized bed (ETFB). These processes include the production of pure graphite, a high-temperature hydrogen-containing gas, pyrocarbon coating, pyrographite, and pure silicon carbide. These problems are solved by theoretical and experimental methods of studying high-temperature processes in the ETFB. To analyze the efficiency of thermal processes and modes of operation, thermodynamic methods, methods of heat and mass transfer theory, methods of similarity theory are used. The important scientific results are: on the basis of thermodynamic calculations the basic thermotechnical characteristics of high-temperature processes which it is expedient to carry out in the ETFB are defined; on the basis of thermodynamic and thermotechnical calculations the basic parameters necessary for creation and design of the new equipment from ETFB are established; the possibility of high-temperature purification of natural graphite of the «Zavaliyevskoye deposit» in the ETFB is theoretically and experimentally proven; a park of experimental equipment with ETFB with different characteristics and method of heating for the study of high-temperature thermochemical processes is created; on the basis of experimental data and with the use of modern microscopic equipment the dependence between the structure of pyrocarbon and thermal parameters of the process of pyrolysis of hydrocarbon gases is proposed; a method for determining the density of the pyrocarbon coating on the dispersed material is developed; conducting a series of experiments on different installations with ETFB the optimal temperature (1500 ° C) and the design of the reactor with ETFB for the yield of 98% vol. hydrogen during the methane pyrolysis reaction are determined; the design of the reactor with ETFB for processing dielectric material by using a combined method of heating is improved; for the first time the temperature of ETFB 3070 °C is experimentally reached; for the first time the formation of silicon carbide from enriched pyrocarbon quartz sand during high-temperature treatment in a reactor with ETFB is experimentally proved; the fundamental possibility of applying a pyrocarbon coating in ETFB on the model of microspherical nuclear fuel, which in their physicochemical properties are close to dispersed nuclear fuel (Dy2O3, Gd2O3, Sm2O3) is experimentally proved; the method of calculating the heat balance for thermochemical processes in a typical reactor with ETFB is improved, during the experimental studies the adequacy of this technique was confirmed; When testing prototypes of extruded gaskets made of thermally expanded graphite (based on graphite purified in ETFB), it was determined that their mechanical strength corresponds to the previously used gaskets of the company "Hydropress" (RF). The research results open up prospects for the creation of energy-efficient and environmentally friendly technology for cleaning natural and artificial graphite; can be used in the creation of hydrogen production for both the chemical industry and metallurgy (high-temperature hydrogen-containing gas); open the prospect of creating an energy-efficient technology for obtaining high-purity fine silicon carbide. The obtained experimental dependences of the structure of pyrocarbon coating on the thermal parameters of the process and the study of its material characteristics open a wide prospect of application of the obtained pyrocarbon coatings in chemical technology, energy, and various high-tech industries. The obtained results on the application of pyrocarbon coating on dispersed materials with high density have the prospect of application in special metallurgy. The results of research on the manufacture of sealing gaskets from thermally expanded graphite were transferred to the Separate subdivision "Atomenergomash" of the State Enterprise "National Energy Company "Energoatom" for the creation of a production site. Full development of the entire cycle of production of thermally expanded graphite seals will eliminate the country's import dependence in this area and increase the safety of domestic nuclear power plants.