Abstract: An apparatus for introducing gas recirculation into a furnace to control steam temperature includes a hot air chamber for receiving hot air from an air preheater. The hot air chamber has at least one outlet communicating with the interior of the furnace. The apparatus includes a recirculation gas chamber for receiving recirculation gas from a recirculation fan and includes at least one outlet communicating with the interior of the furnace. Each of the chambers is disposed about at least a portion of the circumference of the furnace with one of the chambers disposed above at least a portion of the other. Ducts are provided between the hot air chamber and the air preheater and between the recirculation gas chamber and the recirculation fan to provide communication between the elements. A passageway is disposed between the hot air chamber and the recirculation gas chamber.

Abstract: A furnace (10) in which coal and cellulose fuel can both be burned on the same traveling grate (24). First means (36) are provided for introducing coal onto the grate at one end (38), such that it traverses the full grate run before it falls as ash from the other end (56) of the grate. Second means (48, 52) are provided for introducing cellulose fuel onto the grate at a central or middle location (54). Adjustable means (49, 50) are provided for varying the point at which the cellulose fuel is introduced onto the grate. If cellulose fuel having a relatively slow burning rate is being combusted, the adjustable means are set so as to introduce the fuel at a point on the grate further away from the discharge end. If cellulose fuel having a relatively fast burning rate is being combusted, the adjustable means are set so as to introduce the fuel at a point on the grate closer to the discharge end.