Fluidized bed reactor utilizing zonal fluidization and anti-mounding pipes

A fluidized bed reactor comprising a housing, grate means supported in said housing and adapted to receive a bed of particulate material at least a portion of which is combustible, means defining an air plenum extending below said grate means, damper means in said air plenum for dividing said plenum into a plurality of chambers and for selectively controlling the passage of air through said chambers and said grate means to selectively fluidize the corresponding portions of said particulate material extending above said chambers, a pipe extending through each chamber and its corresponding bed portion, means associated with each pipe for selectively admitting pressurized air into said pipe for introducing said pressurized air into its corresponding bed portion to loosen the accumulated particulate material in said latter portion, valve means associated with each air admitting means for cutting off the flow of air into its corresponding pipe to permit the pipe to collect the particulate material building up in the corresponding bed portion, and means associated with said pipes for collecting the latter material from said pipes.