Direct numerical simulation of a non-isothermal non-adiabatic packed bed reactor

•A novel numerical technique to simulate exothermic catalytic packed bed reactors.•Fluid phase and solid phase events are intrinsically coupled.•Ignition/Extinction phenomena due to the multiplicity of steady states are captured.•The hot-spot formation in a wall cooled reactor is analyzed.•The model is free of empiricism with results dependent only on transport and kinetic values. A fundamental continuum-based numerical model was developed to simulate a non-isothermal non-adiabatic reactor which does not employ any empirical closures. The model was able to capture unique features of an exothermic catalytic reactor such as parametric sensitivity, hot-spot formations and multiplicity of steady states. Furthermore, the model inherently accounts for the various aspects of classical phenomenological models such as axial and radial dispersion of heat and mass and the intrinsic coupling of heat and mass transport between the fluid phase and the solid phase. The numerical procedure was validated with existing literature data before moving on to the simulation of a bed consisting of 340 spherical particles packed using the Discrete Element Method. Five simulations were performed by varying the rate of reaction and keeping all other parameters constant to capture the ignition/extinction phenomena exhibited by exothermic packed bed reactors.