Analysis of Heat and Mass Transfer and Parametric Sensitivity in an Experimental Fixed-Bed Reactor for the Catalytic Cracking of Heavy Hydrocarbons Based on Modeling and Experiments

A heterogeneous model for a fixed-bed catalytic cracking reactor of a heavy hydrocarbon stream based on a six-lump kinetic model has been developed for analyzing the operating parameters and describing the heat and mass transfer inside the reactor. Various definitions for the heat-transfer coefficient were investigated using the model. A comparison of the internal and external heat transfer of the reactor showed that it is limited by the heat transfer between the reactor wall and the fluid and plays a major role in the overall heat-transfer coefficient. Also, the weight fraction and temperature profiles demonstrate the same behavior for both solid and gas phases and the difference between the profiles was related to film resistance between the two phases. The results of the model at different temperatures, weight hourly space velocities, and time-on-stream on the distribution of catalytic products and conversion show good agreement with experimental data. The results revealed that moderate conditions are optimal for achieving a higher yield of gasoline, while the amount of undesirable products increased under severe conditions.

Automated summary

A heterogeneous model based on a six-lump kinetic model was developed for analyzing a fixed-bed catalytic cracking reactor of a heavy hydrocarbon stream, in order to study the operating parameters and heat/mass transfer inside the reactor. The results showed that heat transfer is mainly limited by the heat transfer between the reactor wall and the fluid, playing a significant role in the overall heat transfer coefficient.