Patent ID: 7938071

Claim:
A secondary air flow biasing apparatus for a circulating fluidized bed combustion system, comprising: a sorbent feed path configured to convey processed sorbent particles to a circulating fluidized bed furnace chamber by utilizing a portion of secondary combustion air supplied to the circulating fluidized bed furnace chamber; a first air injection port disposed within a wall of a lower portion of the circulating fluidized bed furnace chamber, at a first elevation above a primary air distribution grate of the circulating fluidized bed furnace; a second air injection port disposed within the wall of the lower portion of the circulating fluidized bed furnace chamber, at a second elevation above the first elevation; and an air/sorbent separation device in fluid communication with the sorbent feed path, the separation device configured to separate a substantial portion of the secondary combustion air in the sorbent feed path from the processed sorbent particles in the sorbent feed path such that a relatively lean sorbent-to-air mixture is introduced through the second air injection port and a relatively rich sorbent-to-air mixture is introduced through the first air injection port, wherein the air/sorbent separation device redirects secondary air within the sorbent feed path at an angle of about 120 degrees to about 170 degrees, with respect to an initial direction of the sorbent feed path upstream from the air/sorbent separation device.