Chemical Engineering

Circulating fluidized bed (CFB) in chemical looping combustion (CLC) is a next generation combustion technology, which shows great promise over the spouted fluidized bed in promoting the gas-solid interaction and improving the combustion efficiency in a CLC fuel reactor. In order to demonstrate the effectiveness of this technology, numerical simulation of a laboratory scale CFB reactor for a coal-directed CLC is performed. A combined CFD for hydrodynamics and Dense Discrete Phase model (DDPM) for particle tracking approach is employed in the simulation. ANSYS FLUENT is employed for both CFD and DDPM. The initial simulation using molochite as bed material showed satisfactory agreement with the experimental results obtained at Cranfield University in the UK; which determined the relationship between the solid volume fraction and static pressure in the CFB reactor. The subsequent simulation using FE100 as bed material showed the effectiveness of CFD/DDPM for high density and small diameter bed material, further verifying the importance of static pressure in the circulating system. The simulations show the potential of CFB reactor in CLC and lay the foundation for future simulations of industrial-scale projects.