SYSTEM FOR ASH REINJECTION IN BUBBLING-BED FLUIDIZED BED COMBUSTOR

摘要

An improved reinjection system is described for a bubbling bed fluidized bed combustor of the type having a combustion zone in which fuel is burned in a fluidized bed of granular material, means for collecting particles from the flue gases and means for reinjecting the collected particles into the combustion zone. The improved reinjection system comprises a first particulate material conductor pipe sloping downwardly toward the combustion zone, the lower end of this first downwardly sloping pipe being flow connected by way of a lower corner or elbow to a short section of upwardly sloping pipe. The upper end of this short upwardly sloping pipe is flow connected by way of an upper corner or elbow to a second downwardly sloping pipe. The first downwardly sloping pipe, the upwardly sloping pipe and the second downwardly sloping pipe form therebetween a Z-valve. Air injector means are provided for injecting air into the upwardly sloping pipe to lift the particles therein over the upper corner and further air injector means are provided for forcing the particles from the second downwardly sloping pipe into the fluidized bed of the combustion zone against the back pressure of the bed.