Modelling of binary fluidized bed reactors for the sorption‐enhanced steam methane reforming process

Abstract

ABSTRACTA 1 m high laboratory‐scale and a 4 m high industrial‐scale sorption‐enhanced steam methane reforming (SE‐SMR) fluidized bed reactor were simulated using a three‐fluid model. The performance of the SE‐SMR process was compared with the steam methane reforming (SMR) process. The influences of the superficial gas velocities and the solid loading (packed bed heights) on the reactor performance (hydrogen purity) were studied. The simulation results show that a higher purity of the hydrogen product can be obtained in a SE‐SMR reactor. The superficial gas velocity is an important parameter. In the present study, it has been found that the binary sorbent‐catalyst particles are well mixed when the bed is operated at m/s. The sorbent can adsorb CO steadily, thus the dry mole fraction of the hydrogen product can get above 0.95 in the 1 m laboratory‐scale bed, and above 0.97 in the 4 m industrial‐scale bed. However, when the laboratory scale bed is operated at a lower superficial gas velocity of m/s, the binary sorbent‐catalyst particles are segregated. When the bed is operated at a higher superficial gas velocity of 0.3 m/s, the process work load is increased, and the gas residence time in the reactor is decreased. Therefore, the hydrogen product purity is further decreased. The simulation results also show that there is an optimal bed height limit for the 4 m industrial‐scale bed, at which further increase of the packed bed height cannot increase the hydrogen purity.