Method and apparatus for operating a combined cycle power plant having a defective deaerator
First Claim
1. A combined cycle power plant, comprising:
- a deaerator having primary and secondary functions, said primary function to degasify feedwater for use in the combined cycle power plant;
means for normally coupling said deaerator to the combined cycle power plant as a normally functioning part thereof;
means for isolating said deaerator from the combined cycle power plant during operations thereof; and
alternate means for performing said primary and secondary functions when said deaerator is isolated from the combined cycle power plant, during operations thereof, by said isolating means.
3 Assignments
0 Petitions
Accused Products
Abstract
A deaerating subsystem in a combined cycle power plant includes a deaerator and a storage tank coupled to the deaerator, the deaerating subsystem being adapted for isolation of the deaerator when it is defective even while the overall combined cycle power plant is operating. Blind flanges are provided in a downcomer and in vapor risers between the deaerator and the storage tank for such isolation. Also provided is a condensate bypass for preventing the reception of the condensate by the deaerator, and for enabling the storage tank to receive the condensate directly. Thermal energy is input into the storage tank such that controlled amounts of heated condensate from the steam generator, and controlled amounts of dry steam can be input to the storage tank while the deaerator is isolated for repairs.
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Citations
23 Claims
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1. A combined cycle power plant, comprising:
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a deaerator having primary and secondary functions, said primary function to degasify feedwater for use in the combined cycle power plant; means for normally coupling said deaerator to the combined cycle power plant as a normally functioning part thereof; means for isolating said deaerator from the combined cycle power plant during operations thereof; and alternate means for performing said primary and secondary functions when said deaerator is isolated from the combined cycle power plant, during operations thereof, by said isolating means. - View Dependent Claims (2, 3, 4)
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5. In a deaerating subsystem of a combined cycle power plant which includes a deaerator that is coupled to receive condensate from a source for degasification of the condensate by the deaerator, and a storage tank, the improvement comprising:
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condensate bypass means for preventing reception of the condensate by the deaerator, and for enabling the storage tank to receive the condensate; means for inputting thermal energy into the storage tank, wherein said thermal energy input means is adapted to input controlled amounts of heated condensate and controlled amounts of dry steam; a spray nozzle coupled to said condensate bypass means within the storage tank, said spray nozzle adapted to atomize the condensate; downcomer means for coupling the deaerator to the storage tank to receive the degasified condensate therefrom, said downcomer means including flange means with a blind flange adapted to be inserted within said downcomer means to selectively prevent reception of the degasified condensate by the storage tank; and vapor riser means coupling the storage tank to the deaerator to receive dry steam from the storage tank, said vapor riser means including flange means with a blind flange adapted to be inserted within said vapor riser means to selectively prevent reception of the dry steam by the deaerator; whereby the deaerator, through insertion of said blind flanges in said downcomer means and said vapor riser means, is adapted to be isolated from the combined cycle power plant during operations thereof. - View Dependent Claims (6, 7)
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8. A deaerating subsystem for use in a combined cycle power plant of the type having a gas turbine, a steam turbine, and a steam generator producing motive steam from feedwater that is pumped therethrough by a boiler feed pump, wherein the combined cycle power plant is adapted to be operated at an overall efficiency, said deaerating subsystem comprising;
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a deaerator adapted for receiving a supply of condensate, and for performing a primary function of degasifying said condensate as well as a plurality of secondary functions including heating the feedwater a sufficient amount to prevent corrosion of selected portions of the steam generator, providing a source of the feedwater of a sufficient capacity and head pressure to satisfy requirements of the boiler feed pump during steady state and transient operations of the plant, and providing a location for inputting selected amounts of thermal energy to enhance the overall efficiency; a storage tank coupled to the deaerator by downcomer means, said downcomer means including flange means with a blind flange which is adapted to be inserted within the downcomer means for selectively preventing reception of said degasified condensate by the storage tank; condensate bypass means for preventing the reception of the condensate by the deaerator, and for enabling the storage tank to receive the condensate; means for inputting thermal energy into the storage tank, wherein said thermal energy input means is adapted to input controlled amounts of heated condensate from the steam generator, and controlled amounts of dry steam; and vapor riser means coupling the storage tank to the deaerator for reception thereby of the dry steam from the storage tank, said vapor riser means including flange means with a blind flange which is adapted to be inserted within the vapor riser means for selectively preventing such reception of the dry steam by the deaerator; whereby the deaerator is adapted to be isolated from an operating combined cycle power plant. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of constructing a combined cycle power plant, comprising the steps of:
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providing a deaerator having a primary and secondary functions, said primary function to degasify feedwater for use in the combined cycle power plant; providing means for normally coupling said deaerator to the combined cycle power plant as a normally functioning part thereof; providing means for isolating said deaerator from the combined cycle power plant during operations thereof; and providing alternate means for performing said primary and secondary functions when said deaerator is isolated from the combined cycle power plant, during operations thereof, by said isolating means. - View Dependent Claims (18, 19, 20)
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21. A method of operating a combined cycle power plant that includes a condenser, a heat recovery steam generator including a deaerator adapted to receive and degasify condensate from the condenser and a storage tank coupled to receive the degasified condensate from the deaerator and adapted to store feedwater in the form of the degasified condensate, said method comprising the steps of:
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providing condensate bypass means for preventing the reception of the condensate by the deaerator, and for enabling the storage tank to receive the condensate; providing means for inputting thermal energy into the storage tank, wherein said thermal energy input means is adapted to input controlled amounts of heated condensate from the heat recovery steam generator, and controlled amounts of dry steam; providing a spray nozzle coupled to said condensate bypass means within the storage tank, said spray nozzle adapted to atomize the condensate; providing vent means for the storage tank; providing downcomer means coupling the deaerator to the storage tank for reception thereby of the degasified condensate from the deaerator, said downcomer means including flange means with a blind flange which is adapted to be inserted within the downcomer means for selectively preventing such reception of the degasified condensate by the storage tank; providing vapor riser means coupling the storage tank to the deaerator for reception thereby of the dry steam from the storage tank, said vapor riser means including flange means with a blind flange which is adapted to be inserted within the vapor riser means for selectively preventing such reception of the dry steam by the deaerator; detecting a failure of the deaerator; reducing the operating temperature and pressure of said failed deaerator; isolating said thermal energy inputs to the storage tank; venting said failed deaerator; redirecting flow of the condensate through said condensate bypass means, thereby preventing flow of the condensate to said failed deaerator and permitting same to flow to the storage tank; inserting said blind flanges in said downcomer means and said vapor riser means to isolate said failed deaerator from the storage tank; and reopening said thermal energy input means to the storage tank; whereby the deaerator is adapted to be isolated from the combined cycle power plant during operations thereof. - View Dependent Claims (22, 23)
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Specification