Simulation of Heat and Mass Transfer in an Organic Compound Pyrolysis Reactor

Abstract

Heat and mass transfer processes and decomposition of organic compounds in a pyrolysis reactor are simulated using the ANSYS Fluent software package. Simulation of the pyrolysis of organic compounds, in contrast to simulation of their combustion, is dealt with only in a few studies. However, there are many engineering applications of this process, including thermal decomposition of various wastes where the use of pyrolysis, due to its specifics, seems to be very promising. Because of the wide variety of organic compounds, implementation of their processing in practice using the pyrolysis process depends heavily on the properties of a given feed and requires theoretical justification. A pyrolysis reactor equipped with a mixer is described, and the problem in the computer simulation of wetted polypropylene’s thermal decomposition is formulated. Polypropylene is a component of many medical products, such as catheters, transfusion systems, disposable syringes, etc. It has the highest decomposition heat among all components of medical waste and controls the maximum time of their decomposition. A description is given of a two-phase mathematical model consisting of the well-known mass, momentum, and energy conservation equations, mass transfer equation, and equation of state. The results from calculation of the propylene pyrolysis and the dynamics of thermal decomposition of a solid phase in a reactor are presented. The time of moisture evaporation and pyrolysis of a specimen at 600°С was determined. The hydrodynamic and heat transfer characteristics of the process enabling the performance of a thermal processing package and the requirements for the design of a test facility are considered. The results on the rate and time of polypropylene decomposition offer prospects for predicting the throughput capacity and loading frequency for the investigated reactor.