Analysis of the Unit Performance Degradation for Top Heater Out-of-service Operation Condition

Abstract

To analyze the unit performance degradation for top heater out-of-service operation condition, two calculation methods were introduced, that was the model based calculation method and the simplified variable operation condition analysis method. A 600MW sub-critical steam turbine unit with air cooled condenser was analyzed using the two introduced methods. It is shown that calculation data got can reflect the redistribution effect on steam flows of the turbine extractions and turbine internals due to the top heater out-of-service, and similar and close calculation results were got from the two methods, and both results were lower than result calculated using the commonly used equivalent enthalpy drop method.