Numerical investigation of CO₂ emission and thermal stability of a convective and radiative stockpile of reactive material in a cylindrical pipe

Abstract

In this article, we investigate the combined effects of emission of CO 2 and O 2 depletion on thermal stability in a long cylindrical pipe of combustible reactive material. The cylindrical pipe loses heat by convection and radiation at the surface, and the nonlinear differential equations governing the heat and mass transfer problem are tackled numerically using Runge-Kutta-Fehlberg method coupled with shooting technique. The effects of various thermo-physical parameters on the temperature, CO 2 and O 2 fields, and thermal stability are presented graphically and discussed quantitatively.

Radiation and Thermal Decomposition Analysis in a Reactive Slab of Variable Thermal Conductivity.

“…The exothermic chemical reaction taking place within a stockpile of combustible material is modelled in a rectangular slab. It is assumed that the slab undergoes an n th order oxidation chemical reaction and the complicated reaction is simplified in a one-step finite irreversible process given by [3,4,12] ( ) ( )…”

“…is the numerical exponent such that is for Sensitized (laser induced) kinetics, represents Arrhenius kinetics and is for Bimolecular kinetics, following [3,4,12]. The following dimensionless parameters were introduced to equations (1) -(5)…”

“…Progressive accumulation of heat within the stockpile, due to the exothermic chemical reaction, results in an increase in the temperature. If the temperature of the system keeps on increasing, and the heat loss to the surrounding environment is exceeded by its production due to continued exothermic chemical reaction, thermal runaway that may lead to self-ignition of the stockpile will occur [1,2,3]. The exothermic chemical reaction taking place within a stockpile of combustible material is of environmental importance.…”

“…The exothermic chemical reaction taking place within a stockpile of combustible material is of environmental importance. Previous studies brought to light that about 80% of carbon dioxide contributing to the Greenhouse effect is due to self-ignited fires from neglected stockpiles containing materials such as cotton, hay, wood, or wool, for example [4,5]. The emission of carbon dioxide and heat from ignition processes such as coal burning including other reactive material in households and particularly industries, contributed considerably to climate change and global warming [6,7].…”

Thermal Stability Investigation in a Reactive Sphere of Combustible Material

“…Should the heat generation within a stockpile exceed heat loss to the ambient surroundings, thermal instability and runaway leading to self-ignition may occur [5][6][7]. Thermal explosion criticality concept was investigated by Frank-Kamenetskii and he also developed the steady state theory for combustion of reactive materials due to exothermic chemical reaction [8]. Frank-Kamenetskii's work enables researchers to evaluate thermal criticality values for steady state exothermic chemical reaction.…”