Fluidized bed boiler feed system

Claim 1

A combustion system including a furnace housing enclosing a fluidized bed of coal and limestone that burns to form gaseous products of combustion and residual char, an outlet in said furnace for the exhaust of the products of combustion and said residual char entrained therein, means separating the products of combustion from said char, a source of crushed coal including coarse and fine particles, means separating the coarse particles of coal from the fine particles, means mixing the residual char with the fine particles of coal, means supplying the coarse particles of coal to the top of the fluidized bed in the furnace, a source of transport air, a transport line adapted to supply the transport air to said housing, an inlet in said housing adapted to receive the transport air and exhaust it into the fluidized bed, means supplying a mixture of fine particles of coal and residual char to the transport air whereby they are simultaneously exhausted into the fluidized bed, and means interposed in said transport line intermediate the mixing means and the furnace housing adapted to reduce the fines in the transport air to a dense phase.