144.    BARKER, K. R., SEBASTIAN, J. J. S., SCHMIDT, L. D., AND SIMONS, H. P.  Pressure Feeder for Powdered Coal or Other Finely Divided Solids.  Ind. Eng. Chem., vol. 43, No. 5, 1951, pp. 1204-1209.

                  High cost of compression of the synthesis gas before purification and synthesis to liquid fuels favor gasification at elevated pressures of powdered coal with superheated steam and O₂.  Thus, it was necessary to develop a method of continuous charging of finely powdered coal into a pressurized gas generator.  Experimental work under pressures up to 150 p.s.i. proved that powdered coal can be conveyed pneumatically, in a dense phase (26 lb./cu. ft.), from a fluidized bed and discharged at constant rate.  With other conditions equal, the discharge rate is solely a function of the pressure differential across a conveying line of given dimensions.  The differential pressure across the fluidized coal bed is a direct function of the amount of coal fluidized and, to a lesser extent, of the fluidization rate, but is not influenced by the operating pressure.  For a given rate of fluidization, the amount of coal in the fluidized bed is conveniently gaged by the pressure drop between the bottom and the top of the column.  Regardless of the operating pressure, the amount of coal conveyed per unit volume of gas, measured at the existing pressure, is virtually constant, but the weight of coal carried per unit weight of gas rapidly decreases with increasing operating pressures.  Further work should be done to determine the effects of using various fluidizing gases, such as synthesis gas, air, CO₂, and steam at various pressures and temperatures up to 500° F.