DEPENDENCE OF THE PYROCARBON STRUCTURE ON THE PARAMETERS OF THE PROCESS OF PYROLYSIS OF HYDROCARBON GASES IN AN ELECTROTHERMAL FLUIDIZED BED

One of the variants of the nuclear reactors with increased passive protection being designed at the present time is the reactor with fuel microelements (coated particles) and ball fuel elements. Among the principal components of this type of nuclear fuel is pyrocarbon. Owing to its unique properties, pyrocarbon can also be used in various scientifi c and industrial areas. Over several years, at the Institute of Gas of the National Academy of Sciences of Ukraine, investigations were carried out on obtaining pyrocarbon coatings by means of pyrolysis of hydrocarbon gases in reactors with an electrothermal fl uidized bed. Based on theoretical and experimental data, the present article considers the dependence of the structure of a pyrocarbon coating on the pyrolysis process parameters. Comparing experimental data with theoretical results depending on the temperature and concentration of gaseous hydrocarbon, the structure of the pyrocarbon deposited in an electrothermal fl uidized bed can be divided into three forms: laminar, isotropic, and granular (dropping). Among the factors that infl uence the process of carbon deposition are the content of admixtures and point overheating (cathode spots). Admixtures (mainly iron compounds) can behave as a catalyst accelerating the process of formation of nanotubes and nanofi bers. Controlling the temperature and composition of the original material, it is possible to obtain certain allotropic modifi cations of carbon with assigned structure
   
Author:  K. V. Semeiko, S. S. Kustovskyi, S. V. Kupriyanchuk, and R. E. Chumak
Keywords:  pyrocarbon, electrothermal fl uidized bed, pyrolysis, hydrocarbon gases
Page:  677