Combined cycle power plant with steam turbine bypass for simple cycle operation with heat recovery steam generator and method of use

A combined-cycle power plant, comprising:

• a gas turbine system;
• a steam turbine system;
• a heat recovery steam generator (HRSG) to generate steam from exhaust of the gas turbine system;
• at least one condenser to condense steam from one of the steam turbine system and the HRSG;
• a HRSG steam flow line to supply the steam from the HRSG to the steam turbine system and the at least one condenser, the HRSG steam flow line comprising a first HRSG steam flow line to supply the steam from the HRSG to the steam turbine system and a second HRSG steam flow line branching off the first HRSG steam flow line to supply the steam from the HRSG to the at least one condenser;
• and
• an HRSG steam flow valving arrangement operatively coupled with the HRSG steam flow line, wherein the HRSG steam flow valving arrangement is configured to direct a flow of steam generated in the HRSG to the at least one condenser bypassing the steam turbine system during a simple cycle mode of operation, and wherein the HRSG steam flow valving arrangement is configured to direct the flow of steam generated in the HRSG to the steam turbine system during a combined-cycle mode of operation, and wherein the HRSG steam flow valving arrangement comprises a three-way HRSG steam flow valve.

A method of operating a power plant having a gas turbine system, a steam turbine system, a heat recovery steam generator (HRSG) to generate steam from exhaust of the gas turbine system, and a condenser to condense steam selectively supplied from one of the steam turbine system and the HRSG, the method comprising:

• providing a steam flow valving arrangement having at least one valve that is operatively coupled with the steam turbine system, the HRSG, and the condenser, wherein the steam flow valving arrangement is configured to direct a flow of steam generated in the HRSG to the condenser bypassing the steam turbine system during a simple cycle mode of operation, and wherein the steam flow valving arrangement is configured to direct the flow of steam generated in the HRSG to the steam turbine system during a combined-cycle mode of operation, and wherein the steam flow valving arrangement comprises a three-way HRSG steam flow valve having an inlet to receive the flow of steam generated from the HRSG, a first outlet to direct the flow of steam generated from the HRSG to the condenser, and a second outlet to direct the flow of steam generated from the HRSG to the steam turbine system;
• and
• specifying a position of the at least one valve in the steam flow valving arrangement to operate in the simple cycle mode of operation or the combined-cycle mode of operation, wherein the steam flow valving arrangement is configured to fully stop the flow of steam generated in the HRSG from entering the steam turbine system and to direct all of the flow of steam from the HRSG to the condenser in the simple cycle mode of operation, and wherein the steam flow valving arrangement is configured to fully stop the flow of steam generated in the HRSG from going to the condenser and to direct all of the flow of steam from the HRSG to the steam turbine system in the combined-cycle mode of operation.