Characteristics and diverse applications of (gas)-liquid-solid circulating fluidized beds: A comprehensive review

Circulating fluidized beds (CFBs), specifically the Liquid-Solid Circulating Fluidized Bed (LSCFB) and Gas-Liquid-Solid Circulating Fluidized Bed (GLSCFB), are widely used in chemical, biochemical, and environmental processes. CFBs offer better interfacial contact and reduced backmixing compared to traditional fluidized beds. Understanding the hydrodynamic behavior of (G)LSCFBs is crucial for their optimal design and operation. Reliable measurement techniques for solids concentration, velocity, flow fluxes, and particle sizes are recommended. This article provides an introduction to the hydrodynamics and modeling of (G)LSCFB systems, which is necessary for comprehending their properties and potential applications. Optimizing (G)LSCFB operating conditions benefits various industries. This review includes discussion of several modeling techniques, such as CFD, ANN, and ANFIS in the (G)LSCFB system, which can help to minimize the cost and time required for experimental studies. Additionally, the (G)LSCFB is versatile and useful for designing new bioreactors, especially for simultaneous and independent reaction and regeneration of biocatalyst particles due to its two distinct zones. The article describes the applications of (G)LSCFBs in various fields, including wastewater treatment, polymerization of phenol, lactic acid production, protein recovery, heavy metal removal, and linear alkylbenzene (LAB) production. The essay highlights the unique features of the (G)LSCFB system, which can contribute to exploring new research opportunities and encouraging further investigations in this area.