Influence of hollow structure of honeycomb catalysts on the pressure drop in packed bed reactors

The pressure drop is an important indicator to measure the pros and cons of the fixed bed reactor, which directly affects the reaction performance and comprehensive energy consumption. The shape and size of the catalyst particles are the key factors affecting the pressure drop of the fixed bed reactor. In this work, the effect of hollow structure of honeycomb catalyst pellets (one type of pellets commonly used in the industry) on the pressure drop in packed bed reactors is investigated by using particle-resolved computational fluid dynamics (PRCFD). Firstly, the PRCFD model built in this work is validated by comparing with the voidages and pressure drops obtained from experiments. The deviation between the pressure drops calculated by PRCFD model and obtained from experiments is less than 5%, proving the rationality and accuracy of the PRCFD model. Then, the effect of pore number is investigated. The results show that pore number only very slightly affects the voidage but significantly affects the pressure drop under the same volumes of pore and catalyst. With the increase of pore number, the pressure drop goes up, as the loss of momentum is higher when fluid flows through a smaller pore. Eventually, the effect of pore structure of a Raschig ring catalyst pellet is studied. The voidage and pressure drop can be significantly regulated by adjusting outer cylinder radius, inner pore radius, and height. When the wall of the Raschig ring is thinner, the voidage is higher, resulting in the lower pressure drop. This work can provide a powerful model and some theoretical guidance for the optimal design of catalyst pellet shape. © 2022, Editorial Board of CIESC Journal. All right reserved.