Comparative Study on Different Types of Liquid-Solid Fluidization Systems - Upflow, Downflow and Countercurrent Flow

Comparative study on different types of liquid-solid fluidization systems - upflow, downflow and countercurrent flow

Tian Nan, Jesse Zhu^*

Department of Chemical and Biochemical Engineering, University of Western Ontario, London, Ontario, Canada

This experimental study focusses on different types of liquid-solid fluidization systems categorized based on the flow directions of liquid and solids and relative liquid solid density. In general, heavy density solids tends to settle at the bottom, thus upflow of liquid is often required. On the contrary, downflow liquid is needed to fluidized light density solids from the top. In upflow liquid-solid system, both streams are flowing upwards with heavier density particles. While in downflow systems, liquid and solids are flowing downwards using light density particle. Countercurrent liquid-solid flow is also achieved when heavy particles are falling down while liquid is going up. In addition, the flow directions of liquid and solids can be reversed with light density particle which tends to rise with moderate downflow of liquid. The hydrodynamics under all these flow conditions with corresponding density of particles are experimentally studied and compared systematically. Solids holdup are measured at various superficial liquid velocities and solids flowrates. A flow regime map is generated to conclude different liquid-solid fluidization systems.