13-40: CFD simulation on gas hold up and mass transfer characteristics in a novel airlift reversible loop bioreactor

As a classical reactor, Airlift Loop Reactor (ALR) has been widely used in petrochemical, biochemical, energy, and environmental processes. Giving many advantages such as simple structure, no motional mechanism, ease of sealing and low energy consumption, ALR is usually employed as a bioreactor in many bio-processes. We have developed a novel airlift loop reactor by using Forced Periodic Operation, which is called Airlift Reversible Loop Reactor (ARLR). Through the Periodic Operation, the oxygen mass transfer is improved without increasing energy consumption obviously. By using CFD simulation and experimental validation, the structural parameters such as height to diameter (H/D) ratio, draft tube diameter and operation frequency were optimized. Compared with the traditional ALR, ARLR increases the gas hold up rate by 50% and oxygen mass transfer coefficient by 20%. The results indicate that the ARLR can be used in the highly aerobic fermentation instead of using the energy-intensive stirred reactor.