Increasing Steam Turbine Capacity

Steam turbine owners are often searching for opportunities to increase power output. Increases in steam turbine flow capacity yield a proportional increase in power output, but there is more to increasing capacity than just opening up nozzle areas. This paper describes how Mechanical Dynamics and Analysis personnel increased the flow capacity and power output using original blading on a large, supercritical, reheat unit while maintaining a high level of efficiency. Much attention was given to the as-left stage properties in order to minimize the change in efficiency from the design levels. The work is documented using a timeline which centers on the outage. Much of the engineering work done prior to the outage minimized the time necessary during the outage to complete the modifications. Before and after test results demonstrate the cost-benefit of the capacity increase.