Furnace cooling by steam and air injection
AssigneeThe Babcock & Wilcox Company
InventorsMikhail Maryamchik, Michael J Szmania, Donald L Wietzke
Life of this patent
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Abstract
A system can quickly cool and de-pressurize a boiler arrangement under non-normal operating conditions such as loss of plant power. A discharge system injects into the furnace a combined stream of steam from a steam discharge system and ambient air, thereby both cooling components of the boiler arrangement and reducing pressure in the steam/water circuit. This reduces or eliminates the additional cost associated with providing extra capacity in a steam drum and/or an independently powered boiler water pump. The system is particularly useful for quickly cooling the U-beams of a circulating fluidized bed boiler during a black plant condition.
Claims20
In a circulating fluidized bed boiler arrangement that comprises a furnace with at least one primary air inlet and one or more secondary air inlets, a solids separator system, a steam/water circuit for circulating steam and water, and a steam discharge system, a system for cooling components of said boiler arrangement during abnormal operating conditions comprising:
- a) at least one of said one or more secondary air inlets comprising a valve which, in an opened conditions, permits ingress of air external to said boiler arrangement;
- b) conduit for conveying steam out of and away from the steam discharge circuit, said conduit providing ingress to said at least one secondary air inlet;
- and
- c) in or associated with said secondary air inlet, an eductor in communication with said steam conveyance conduit, said eductor being capable of outputting a combined stream of said external air and said conveyed steam to said furnace during abnormal operating conditions.
A method for facilitating the cooling of components of a circulating fluidized bed boiler arrangement that comprises
- (1) a furnace with at least one primary air inlet and one or more secondary air inlets, wherein at least one of said one or more secondary air inlets is adapted to communicate with an air valve and encloses an eductor,
- (2) a solids separator system and
- (3) a steam/water circuit for circulating steam and water, said method comprising:
- a) conveying steam out of and away from said steam/water circuit to said eductor;
- and
- b) allowing said eductor to combine said steam with air introduced through said air valve, said air originating from a source external to said boiler arrangement;
- and
- c) introducing said combined stream into said furnace, thereby reducing the internal temperature of said furnace and helping to cool said components.
Dependencies are inferred from the claim text.