US 8,984,892 B2 · Combined cycle power plant including a heat recovery steam generator

Abstract

A combined cycle power plant includes a gas turbomachine, a steam turbomachine operatively coupled to the gas turbomachine, and a heat recovery steam generator operatively coupled to the gas turbomachine and the steam turbomachine. The heat recovery steam generator includes a high pressure reheat section provided with at least one high pressure superheater and at least one reheater. The combined cycle power plant further includes a controller operatively connected to the gas turbomachine, the steam turbomachine and the heat recovery steam generator. The controller is selectively activated to initiate a flow of steam through the heat recovery steam generator following shutdown of the gas turbomachine to lower a temperature of at least one of the high pressure superheater and the at least one reheater and reduce development of condensate quench effects during HRSG purge of a combined cycle power plant shutdown.

Claims14

Dependent claims

A combined cycle power plant comprising:

a gas turbomachine;
a steam turbomachine operatively coupled to the gas turbomachine;
a heat recovery steam generator (HRSG) operatively coupled to the gas turbomachine and the steam turbomachine, the heat recovery steam generator including a high pressure reheat section provided with at least one high pressure superheater and at least one reheater;
and
a controller operatively connected to the gas turbomachine, the steam turbomachine and the heat recovery steam generator, the controller being configured to selectively initiate a flow of steam through the heat recovery steam generator following shutdown of the gas turbomachine responsive to calculating a difference between a sensed temperature and pressure of a fluid in the at least one high pressure superheater and a superheater discharge steam temperature and determining that the calculated difference is less than a threshold value to lower a temperature of the at least one high pressure superheater and the at least one reheater and reduce development of condensate quench effects during HRSG purge of a combined cycle power plant shutdown.

2 more elements

A method of cooling a high pressure reheat section of a heat recovery steam generator (HRSG) having at least one high pressure superheater and at least one reheater during combined cycle power plant shutdown in order to reduce condensate quench effects during HRSG purge, the method comprising:

decelerating a gas turbine portion of the combined cycle power plant to turning gear speed;
receiving a sensed temperature and pressure of steam in the at least one high pressure superheater;
receiving a sensed superheater discharge temperature;
calculating a difference between the sensed superheater discharge temperature and a saturation temperature of the steam in the at least one high pressure superheater;
ramping down operation of a steam turbine portion of the combined cycle power plant responsive to determining that the calculated difference is not less than a threshold value;
and
flowing the steam through the heat recovery steam generator to lower internal temperatures of at least one of the at least one high pressure superheater and at least one reheater, wherein lowering internal temperatures of the one of the at least one high pressure superheater and at least one reheater reduces the condensate quench effect during a purge of the HRSG responsive to determining that the calculated difference is less than the threshold value.

4 more elements

Dependencies are inferred from the claim text.

Combined cycle power plant including a heat recovery steam generator

Life of this patent

Combined cycle power plant including a heat recovery steam generator

Life of this patent

Abstract

Claims14