Method for feeding dry coal to superatmospheric pressure

Claim 1

In a method of gasification of coal wherein the coal in particulate form and reactant gases are passed upwardly through a reaction zone under conversion conditions of temperatures up to 1800*F and pressure up to 1450 psig for the gasification of the coal, the improvement which comprises: a. drying and grinding the coal to a moisture content of not to exceed five weight percent and a grind less than 1/4 inch; b. mechanically boosting the pressure on said coal solids in stages from atmospheric to reaction zone pressure by use of high speed screw pumps; c. introducing said pressurized, substantially dry coal particles into the reaction zone in the absence of a carrier liquid; and d. simultaneously measuring and controlling the weight flow of coal particles into the reaction zone to provide a constant weight flow of coal into the reaction zone.