Light fuel start-up fluidized bed combustor

Claim 1

A fluidized bed combustor comprising: a combustion chamber; a distributor plate assembly at the bottom of said combustion chamber; said assembly including a housing forming a first air plenum and a second air plenum; an inverted pyramidal surface in the top of said housing, projecting down into said first plenum; said surface having slots with offset shields thereabove forming laterally oriented air flow openings from said first plenum to said combustion chamber such that air flow therethrough will cause debris particle classification along said surface as well as contributing to bed fluidization and supplying combustion air; air flow riser tubes projecting up from said second plenum to a position elevated above said surface, having air inlets adjacent the bottom of said riser tubes and air outlets adjacent the top thereof; said riser tubes comprising a first set for supplying fluidizing and combustion air to said combustion chamber, and a second set; the riser tubes of said second set projecting vertically above the riser tubes of said first set, and having liquid fuel nozzles for injection of light liquid fuel into the risers of said second set for elevation and discharge of the fuel with air flow through said second set and into said combustion chamber; forced air supply means to said housing for air flow thereto under pressure; and air flow control means for regulating the relative flow at said first and second plenums to thereby regulate flow through said slots in said surface relative to flow through said riser tubes.