HYDRODYNAMICS OF SPOUTED BEDS AT ELEVATED TEMPERATURES

Abstract

A review of the literature reveals little information on the hydrodynamics of spouted beds at high temperature. Most existing correlations are based upon experiments done at ambient conditions; they have not usually been tested with data at higher temperatures. The present study focussed on obtaining data over a temperature range of 20-420°C. Spouting of three sizes of Ottawa sand with preheated air was couducted in a 156 mm diameter stainless steel semi-cylindrical column with a 60° included angle half-conical base. A transparent wire-glass panel on the flat face allowed measurement of parameters which are otherwise difficult to obtain in a full stainless steel column. In addition to air, helium and methane at room conditions were used as spouting gases. With these two additional gases, it became possible to investigate the effect of changing gas density at constant viscosity and the effect of changing gas viscosity at constant gas density. In general, it was found that the range of stable spouting decreased with decreasing gas density and increasing gas viscosity, hence with increasing air temperature. Existing equations for various spouted bed parameters were tested and, where necessary, empirically modified to fit the new data obtained. @KEYWORDS Spouted bed hydrodynamics, High temperature gas spouting, Temperature effect on spoutability