Fuel supply method for a gasification chamber

Claim 1

Method of supplying particulate solid fuel material to a pressurized combustion-gasification chamber by means of a screw conveyor comprising at least two screws rotatably driven at the interior of a sleeve debouching at its downstream end into said chamber, said material being charged into said sleeve at its upstream end and being moved by said screws toward said downstream end, said material passing into a compression zone located at said downstream end so as to form a fluid-tight plug of compressed material introduced into said chamber and continuously renewed by material arriving from upstream, characterized in that said material is first mixed outside of said screw conveyor with a liquid phase constituting a moderator combustion fluid so as to form a mixture containing at least 40% by weight of liquid phase, said mixture then being charged by pumping into the inlet of said screw conveyor, said screws having different threading defining a drive zone in the downstream direction and a compression zone in which said fluid-tight plug is formed by expulsion of said liquid phase and compression of said combustible material, the flow rate of feeding said mixture and the speed of rotation of said screws being mutually adjusted in such manner as to maintain at the outlet of said screw conveyor a substantially constant pressure corresponding to a substantially constant proportion of liquid phase of at most 15%, any excess of said liquid phase beyond said proportion being expelled upstream and evacuated by filtering parts arranged in said sleeve upstream of said compression zone.