Fluidization behavior in high-pressure water at temperature from ambient to supercritical

Abstract

The fluidization behaviors of Geldart-A and B particles in high pressure, sub-critical and supercritical water were investigated experimentally with the conditions of pressure up to 27.2MPa and temperature up to 482°C. Minimum fluidization velocity was determined by measuring pressure drop. Minimum bubbling velocity was obtained not only by analysis of the experimental differential pressure fluctuation signals, also by the relationship between bed voidage and superficial velocity. Correlations for the minimum fluidization velocity, homogeneous bed expansion rate and the minimum bubbling velocity were proposed. Transitions of fluidization regimes: fixed–homogeneous (F-H), fixed-homogeneous-bubbling (F-H-B) and fixed-bubbling (F-B) were uncovered at temperature from ambient to supercritical. The fluidization of F-H was found when discrimination number Dn is below 1.2×104, and the fluidization of F-H-B was found when discrimination number Dn is between 1.2×104 and 6×104, the fluidization of F-B was found when discrimination number Dn is above 6×104. These results are very useful for the design of the high pressure, sub-critical and supercritical water fluidized bed.