Goodbye cavitation
The plant consists of four gas turbines and two steam turbines and generators supplied by MHI (Mitsubishi Heavy Industries) and the six BFW pumps supplied by Hyosung Goodsprings.
Ever since the commissioning stage of the plant in 2015, the plant has faced serious cavitation problems in the AR Valves protecting the pumps because the ARVs are often operated under extremely critical operating conditions.
Plant operation logic and TCA Cooler operations require low flow rates below pump minimum flow, which makes the AR Valves operate at partial-load and quite often daily startup/shutdown operation.
Flow rates
The main reason for cavitation was the – at times – very low flow rate and, thus, critical load condition of the valves. Low flow rates often cause cavitation in AR Valves.
In the current plant concept, which today is common for most CCPPs, each of the three boiler feed pumps (per steam turbine) has the capacity to provide the full rated flow of the HRSG-drum....