Apparatus for introducing gas recirculation to control steam temperature in steam generation systems

摘要

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. The apparatus includes a valve movable between a first position wherein flow through the duct from the recirculation fan is blocked and flow through the passageway is open and a second position wherein flow through the passageway is blocked and flow through the duct from the recirculation fan in open.