Condensing equipment is Condensing steam turbine an important component. Due to factors such as design, installation, maintenance, and operational mechanisms, the condenser vacuum often drops during operation. If the condenser vacuum is too low, not only will the effective enthalpy drop of steam within the unit be reduced, but also the thermal efficiency of the cycle will decline, leading to an increase in the exhaust steam temperature of the turbine, deformation of the exhaust cylinder, and vibration. Under normal operating conditions, the relationship between the condenser exhaust pressure and exhaust temperature is that of saturated steam.

The manufacturer of condensing steam turbines believes that the reasons and characteristics for low vacuum operation in condensers are as follows:

(1) When the circulating water pump experiences a serious malfunction, the circulation of water will be interrupted.

The manufacturer of condensing steam turbines identifies the following as the main fault characteristics: the motor current of the circulating water pump drops to zero, the pressure at the pump outlet falls to zero, and the temperature difference between the air extracted by the ejector and the inlet temperature of the cooling water increases.

(2) When the steam supply to the rear shaft seal is suddenly interrupted, a large amount of air will leak into the condenser, causing its vacuum to drop sharply.

The main fault characteristics are: an increase in the end difference of the condenser, a rise in the subcooling of the condensate, and negative differential expansion of the rotor due to rapid cooling.

(3) When the condenser water level fails to be properly regulated—resulting, for example, in a full condenser—the heat exchange area between the exhaust steam and the cooling water will decrease dramatically, causing the condenser vacuum to drop sharply.

Condensing steam turbine The manufacturer identifies the following as key fault characteristics: an increase in the end difference of the condenser, a rise in the subcooling of the condensate, a decrease in the temperature rise of the circulating water, an increase in the discharge pressure of the condensate pump, a rise in the current drawn by the pump motor, and an increasing temperature difference between the air drawn from the intake port and the inlet temperature of the cooling water.

(4) When a pipe in the vacuum system ruptures, the condenser vacuum will drop.

The main fault characteristics are: an increase in the end difference of the condenser, an increase in the subcooling of the condensate, and a sharp drop in vacuum.

(5) When the vacuum system is not airtight, the vacuum will drop.

The main fault characteristics are: an increased end difference in the condenser, increased subcooling of the condensate, and a slow decline in vacuum.

(6) When the condensate pump is malfunctioning, the vacuum will drop.

The manufacturer of condensing steam turbines identifies the following as key fault characteristics: an increase in condenser water level, a larger end difference, greater subcooling of the condensate, a decrease in the discharge pressure of the condensate pump, and a reduction in the current drawn by the condensate pump motor.

(7) When part of the condenser’s copper tubes ruptures during operation, the vacuum in the condenser will decrease.

The main fault characteristics are: an increase in condenser water level, a larger temperature difference between the inlet and outlet, increased subcooling and conductivity of the condensate, higher discharge pressure at the condensate pump outlet, and increased current draw by the condensate pump motor.

(8) If the condenser copper tubes are dirty, the heat transfer efficiency will decrease, and the vacuum will drop.

Condensing steam turbine The manufacturer identifies the main fault characteristics as follows: the end difference increases, the temperature rise between the inlet and outlet of the circulating water decreases, and the temperature difference between the air drawn from the intake port and the inlet temperature of the cooling water widens.

(9) When the condenser copper tubes are blocked (or the circulating water supply is insufficient), the vacuum in the condenser will drop.

The manufacturer of condensing steam turbines identifies the main fault characteristics as follows: an increase in end difference, a rise in the inlet and outlet temperatures of the circulating water, and an increased temperature difference between the air drawn from the intake port and the inlet temperature of the cooling water.

(10) When the ejector is malfunctioning, the vacuum in the condenser will decrease. The main fault characteristics are: an increased end difference, greater subcooling of the condensate, and a reduced pressure differential between the condenser’s suction inlet and the suction port.