A fluidized bed was partitioned internally into two compartments which are interconnected through a passage inside the bed.The particles

which represent a kind of solid feedstock

are fed into one of the compartments and flow out the bed from the other compartment

resulting in a U-shaped pathway of the particle flow.This kind of bed is thus called the U-shaped fluidized bed(UFB)

and is suitable for conducting the decoupling gasification of biomass with high water contents.The fluid dynamics of the quartz sand fluidized by air in a laboratory cold UFB  were investigated via both experiment and the FLUENT modeling.The FLUENT modeling revealed that it was necessary to install a perforated plate into the compartment from which particles flow out for achieving the expected uniform distribution of gas entering this compartment from the other compartment.The cold model test results verified this point and demonstrated that the UFB required a range of fluidizing gas velocities for ensuring the normal operations of the UFB.The pressure balance between the two compartments of the bed was found to be the factor controlling the particle fluidization and gas distribution in the UFB.Analyzing the particle residence time in the UFB clarified further that the residence time distribution was very close to the predicted profile via the CSTR model.