Water Losses in the Condenser Cooling System at the 905 MWe Power Unit

Abstract

The paper focuses on water losses in the turbine condenser cooling system of the 905 MW power unit in Opole Power Plant (Opole Poland). The evaporative and drift losses are determined for various operating and atmospheric conditions. The drift loss is found to be 0.125–0.375% of the cooling water flux and some increase in this loss is noticed with increase in unit power and ambient temperature. The studies have shown that the presence of wind increases the total water loss related to the power generated by the power unit. This effect is analysed for selected constant air temperature values Tamb. The increase of the cooling water loss stream, related to the power of the unit, is at the level of 14.8% for Tamb equal to 7 °C, 23% for 15 °C, and approximately 10% at 22 °C. These increases are related to the level of losses in almost no wind conditions. It is investigated how the change in the cooling water flux affects the power unit operation and the amount of water loss. For the power unit under consideration, the reduction of the cooling water flux from 80,000 to 60,000 ton/h raises the temperature of water behind the condenser and lowers the temperature of the cooled water tw2 within the range of 0.75–1.5 °C, depending on the unit power and the ambient temperature. Reducing the cooling water flux in the analysed range results in an increase in condenser vapour pressure, within 0.5 kPa at Tamb = 25 °C. This increase is lower at lower ambient temperatures. Within the range of variations analysed, the effect of cooling water flux on evaporative losses is negligibly small. The increase in condenser steam pressure significantly affects the power generated by the turbine generator unit. The calculations show that it is possible to optimize the size of the cooling water flux for the analysed power unit and condenser cooling system. This optimization would allow (within a limited range of load variability) an increase in the net power generated by the power unit.

Keywords

• cooling tower
• cooling water system
• ambient conditions
• water loss
• power plant