Simulation of Crude Oil to Chemicals Based on Mesoscale Filtered Drag Subgrid Model

The riser reactor of catalytic cracking of crude oil to chemicals (COTC) contains gas-solid heterogeneous structures represented by a particle cluster naturally. To more accurately describe the COTC, a dominant filtered drag model was established considering the reduction of an interphase exchange coefficient (k(sg)) for particle cluster existence. With the updated filtered drag model, a modified Euler-Euler two fluid model (model A) was proposed and verified. Then, model A coupled with the 4-lump COTC reaction kinetic model and reaction enthalpy model was used to construct a new heterogeneous filtered two-fluid model (FTFM, model B). The mass fraction of the cracking products calculated by FTFM was in good agreement with those obtained in the experiment. Meanwhile, the effects of the catalytic cracking reaction on drag parameters were discussed. The results show that catalytic cracking reaction and reaction heat can lead to k(sg) decreasing, and mesoscale structures can be observed intuitively with the revised filtered model. The constructed model and methodology in this work can be used to accurately predict the cracking products distribution, which could decrease the designing and optimizing costs of an industrial COTC reactor.