City University London and Centre for Research and Technology Hellas
The conversion of heavy hydrocarbons to lighter ones in fluid catalytic cracking (FCC) reactors relies on the mixing and evaporation of injected gas oil droplets and their collisions with catalyst particles inside the reactor. Product selectivity can vary greatly due to petroleum composition uncertainty. Also, catalyst deactivation that occurs when liquid blocks the catalyst pores decreases FCC unit efficiency.
Researchers at City University London (CUL) and the Centre for Research and Technology Hellas (CERTH) used ANSYS Fluent to simulate various droplet–catalyst collision scenarios inside FCC reactors. They developed User Defined Functions (UDFs) to produce an interphase evaporation model and an extension of the basic grid refinement technique. The simulated collision scenarios provided important information concerning droplet heat-up and lifetime, as well as the formation of cracking products. The results showed that collisions between droplets and hot catalysts of equal size are expected to improve conversion, while also limiting liquid–pore blocking. The model successfully estimated the yield of cracking products, and simulated every possible droplet–catalyst collision scenario. The dynamic grid refinement technique saved valuable computation time. Researchers at CUL and CERTH would like to thank the European Commission for funding this work, by the Marie Curie Fellowship (FP7-PEOPLE-2012-IEF), GA No 329500 entitled as “Non Flat Impingement”.