ELECTRIC POWER RESEARCH INSITUTE (EPRI) （电力科学研究院(EPRI)）.pdfVIP

ELECTRIC POWER RESEARCH INSITUTE (EPRI) 2011 CONDENSER TECHNOLOGY CONFERENCE AUGUST 3-4, 2011, CHICAGO, ILLINOIS IMPORTANCE OF TEMPERATURE OF BYPASS STEAM ADMITTED INTO A STEAM SURFACE CONDENSER IN A COMBINED CYCLE PLANT BY Ranga Nadig, Ph.D., President Michael Phipps, P.E., Vice President Maarky Thermal Systems 1415, Route 70 East, Suite 604 Cherry Hill, NJ, 08034 ABSTRACT: The past decade has witnessed the commissioning of hundreds of large and small combined cycle plants worldwide. In a combined cycle plant, the steam surface condenser must condense the turbine exhaust steam (normal operation) as well as the bypass steam (steam turbine bypass operation). Bypass operation is encountered when the gas turbines are in service and the steam turbine is out of service (startup, shutdown, trip, etc.). With only the gas turbines in operation, high-pressure steam from the HRSG is attemperated in a pressure reducing/desuperheating (PRD) valve and then admitted into the condenser. The total bypass steam flow can be as high as 150%-200% of the design turbine exhaust flow and the duration of bypass operation can vary from a few hours to a few weeks. The enthalpy of the steam exiting the PRD valve is selected anywhere between 1190 Btu/lb to 1225 Btu/lb and the pressure downstream of the PRD valve is established anywhere between 40 psia to 250 psia. In certain low-pressure bypass application, the PRD valve is altogether eliminated and bypass steam at relatively high temperature is admitted into the condenser. The current