Study on Variable Working Condition Characteristics of 600 MW Direct Air Cooling Condenser

Abstract

The coal consumption of direct air cooling unit is higher than that of wet cooling unit, and its back pressure is easily affected by environmental factors. Therefore, it is of great significance to study the exhaust pressure characteristics of air condensing unit under variable working conditions for the safe and economic operation of the unit.The ε-NTU method was used to establish the mathematical model of the 600 MW direct air cooling unit under the condensing condition. The characteristic curves of the condenser under the condensing condition were calculated. The effects of the face wind speed, ambient temperature and exhaust flow rate on the exhaust pressure were analyzed. The conclusions are as follows: When the ambient temperature is higher and the exhaust steam flow is constant, the back pressure economy is better when the head wind speed is 2.5 m/s. During the period of high temperature in summer, the exhaust steam pressure of condenser increases significantly with the increase of exhaust steam flow and the decrease of head-on wind speed. It is necessary for the unit to operate under limited load and appropriately increase the fan speed to reduce the back pressure. When the ambient temperature is low, the exhaust steam flow rate and the face wind speed have little influence on the exhaust steam pressure of the condenser, so it is necessary to take anti-freezing measures. Appropriately increasing the exhaust steam pressure of the condenser is beneficial to the safe operation of the air-cooled island.

Keywords

• direct air cooling
• condenser
• variable working condaton
• characteristic curve
• run advice