Study on flow characteristics of turbulent fluidized bed with variable gas velocity due to chemical reactions

Industrial reactors often involve change in volumetric flow rate of gas phase due to chemical reactions, which can have significant effects on the gas-solid flow field in the reactor. The common method to study these effects usually injects additional gas along the bed height, which can introduce abrupt change in flow hydrodynamics. This work compares such common method and a method with constant change of volumetric flow rate of gas phase using Computational Fluid Dynamics (CFD) simulations. It was found that the common method can significantly influence the particle flow behaviors near the sidewall and weaken the core-annular flow pattern. Such common method can make the radial distribution of the solids holdup more uniform, which derivates from the real industrial conditions. With more cases focusing on different changes of gas velocity and bed expansion ratio, it was demonstrated that the change in volumetric flow rate of gas phase due to chemical reactions should be appropriately treated for providing adequate and accurate information for operation and design of industrial turbulent fluidized bed reactors.