RESEARCH THERMAL CHARACTERISTICS OF THE PROCESS OF PYROLYSIS OF METHANE IN THE ELECTROTHERMAL FLUIDISED BED

Abstract

The main products of high-temperature pyrolysis of methane are carbon and hydrogen. Due to their unique physical and chemical properties, pyrocarbon and pyrographite can be used in various industries and energy. Hydrogen is an energy-efficient and environmentally friendly energy carrier. Despite the large number of research works on methane pyrolysis, carrying out of this process in the electrothermal fluidized bed (ETFB) is not studied enough. The purpose of the study is to determine the thermophysical characteristics of the process of methane pyrolysis (the main products of the reaction are hydrogen and pyrocarbon) in reactors with different types of ETFB. The temperature of the complete disposition of methane to carbon and hydrogen is 800 K. This value is based on the thermodynamic calculations. A laboratory and a pilot plant with a different type of ETFB have been created for this process. Experimental studies of the process of methane pyrolysis had been carried out on these plants and experimental data were compared with the calculations. The method which allows to determine the amount of precipitated carbon has been developed. It is based on the gas analysis data. Nusselt's criterion for different types of reactors with ETFB has been calculated. It was showed that electrothermal heating of a fluidized bed of conductive particles is much more efficient than the external electric heating of a fluidized bed. This result is based on previous researches. It is explained by the direct influence of the plasma of microcircuits and by advantages of heat generation directly in the middle of the fluidized bed. Taking into account the obtained results and the specifics of the application of the pyrocarbon coating on dielectric materials, a scheme of a reactor with ETFB, which allows to use both external heating and classical ETFB at the same time, has been developed.