Method for calculating the pyrolysis zone in the production unit activated carbon

Abstract

Activated charcoal can be obtained in many ways. The most promising in terms of resource saving and economic benefits is the method of obtaining activated carbon from organic waste by slow conductive pyrolysis. As a result of such thermochemical conversion, biochar and volatile products - condensable and non-condensable are formed, which are used as fuel for the operation of pyrolysis reactors. Modeling of slow thermal decomposition is carried out using finite difference schemes for heat and mass processes described by differential equations and equations of chemical kinetics. The pyrolysis process equipment is a complex and expensive mechanism, therefore, when developing equipment for pyrolysis, it is necessary to carry out calculations related to the optimization of the equipment design. In this work, as applied to an energy- and resource-saving plant for the production of activated carbon, analytical calculations were carried out and a universal calculation method was developed for the zone of conductive pyrolysis of crushed waste. A mathematical model of the process of conductive slow pyrolysis is presented, which consists of heat and mass transfer equations and equations of chemical kinetics. An algorithm for calculating the pyrolysis zone has been developed. A kinetic dependence of the specific gravity of the solid residue of wood particles during pyrolysis is obtained, which characterizes mass transfer during the thermochemical transformation of waste into a carbonaceous residue, this dependence shows the dynamics of the change in the mass of the solid fraction over time during the decomposition of waste, the kinetic curves show: the rate of chemical reactions occurring during pyrolysis, as well as the final specific gravity of coal.