PHASE HOLDUP AND LIQUID DISPERSION IN GAS-LIQUID-SOLID CIRCULATING FLUIDIZED BEDS

摘要

Axial and radial profiles of gas and solids holdups have been studied in a gas-liquid-solid circulating fluidized bed at 140mm i.d.. Experimental results indicate that the axial and radial profiles of gas and solids holdups are more uniform than those in a conventional fluidized bed. Axial and radial liquid dispersion coefficients in the gas-liquid-solid circulating fluidized bed are investigated for the first time. It is found that axial and radial liquid dispersion coefficients increases with increaes in gas velocity and solids holdup. The liquid velocity has little influence on the axial liquid dispersion coefficient, but would adversely affect the redial liquid dispersion coefficient. It can be concluded that the gas-liquid-solid circulating fluidized bed has advantages such as better interphase contact and lower liquid dispersion along the axial direction over the expanded bed.