Simulation of 2D Riser Regenerator

Abstract

Riser regenerators are regenerating vessels used for removing the coke deposited on the catalyst and provide heat of reaction for the cracking process. Coke formation is unavoidable in the catalytic cracking process, which is probably formed by the dehydrogenation and condensation of poly-aromatic and olefins. Fast deactivation by blocking the active pores of the catalyst is a consequence of coke deposition. Riser regenerators are used for regenerating spent FCC catalyst by burning the coke deposited on the catalyst body. These are better compared to the conventional turbulent fluidised beds due to large capacities, higher gas-solid contact efficiency, high heat and mass transfer rates and low solids inventory. These regenerators also offer advantages over conventional scale reactors such as reaction speed, greater combustion of coke, reliability, cost effective, scalability and better safety and control. The present work is aimed to study the behaviour of regeneration reaction of coke inside riser regenerator. The advantages of multiple air inlet riser regenerator have been found out by studying the phenomenon inside the regenerator. The transient simulation has been carried out. The transient solution shows the species concentration and temperature profile inside the riser regenerators. The result reveals that the temperature of the gas increases with axial length and species concentration decreases. It has been found that multiple air inlet regenerator provide a better combustion than the single inlet regenerator.