HYDRODYNAMIC BEHAVIOR OF A LIQUID-SOLID FLUIDIZED-BED REACTOR FOR THEBIOCONVERSION OF COAL PARTICLES TO LIQUID PRODUCTS

A predictive mathematical model based on particle convection and dispe rsion is presented for a liquid fluidized bed of coal particles. The n umerical representation can follow transient behavior of liquid fluidi zed beds that contain a defined particle-size distribution. The calcul ations exhibited excellent agreement when compared to experimental tra nsient pressure-drop data from a column containing particles of Illino is No. 6 bituminous coal in the size range of 20-120 mu m. In addition , the model was used to simulate the effect of periodic (hourly) liqui d velocity step changes on elutriation of small particles from a given particle-size distribution of 34.5-75.5 mu m. For the situation teste d, the calculations indicate that (a) the column does not reach a stea dy state between velocity changes and (b) that higher initial particle elutriation rates decay to lower values until no more particles elutr iate from the column.