The condenser as Condensing steam turbine The main condensing equipment of the unit is tasked with establishing and maintaining a high vacuum at the turbine exhaust port, condensing the turbine exhaust steam into water, and then pumping this condensed water via a condensate pump to the deaerator, where it is converted into boiler feedwater. The vacuum in the condenser directly affects the normal operation of the unit. It can be said that the operational performance of the condenser has a direct impact on the safe and economical operation of the turbine unit.

The manufacturer of condensing steam turbines believes that the primary reason for the high vacuum in the condenser is that the exhaust steam from the turbine is cooled and condensed into water, causing its specific volume to decrease dramatically. For example, when the absolute pressure of steam is 4 kPa, the volume of steam is more than 30,000 times greater than the volume of water. As soon as the exhaust steam condenses into water, its volume shrinks significantly, thereby creating a high vacuum within the condenser.

Condensing steam turbine The manufacturer considers the condenser to be a heat-exchange device that converts the steam discharged after driving the turbine into condensed water. After the steam undergoes an expansion process in the turbine, its exhaust volume drops sharply during the condensation process, creating a high vacuum in the space previously filled with steam. The condensed water is then pumped by the condensate pump, passed through the feedwater heater and feedwater pump, and finally delivered to the boiler, thereby ensuring the continuity of the entire thermodynamic cycle. Its functions are as follows:

1) By creating a high vacuum at the steam turbine exhaust port, the steam expands to the lowest possible pressure within the turbine, thereby increasing the available enthalpy drop of the steam and improving the thermal efficiency of the cycle.

2) Condense the steam discharged from the low-pressure cylinder of the steam turbine into water and send it back to the boiler for reuse in the cycle;

3) Collect various types of drainage to reduce steam-water loss.

4) The condenser is also used to increase softened water (normal make-up water).

The manufacturer of condensing steam turbines believes that the essential conditions for forming and maintaining condenser vacuum are:

1. The condenser copper tubes must be passed through a certain amount of cooling water;

2. The condensate pump must continuously remove condensate to prevent the water level from rising and affecting steam condensation.

3. The ejector must extract the leaking air and other non-condensable gases from the steam.

Condensing steam turbine The manufacturer defines the difference between the saturation steam temperature at the condenser pressure and the outlet temperature of the condenser cooling water as the end difference. For a given condenser, the end difference is influenced by several factors, including the inlet temperature of the condenser cooling water, the steam load per unit area of the condenser, the cleanliness of the copper tubes in the condenser, the amount of air leakage into the condenser, and the flow rate of the cooling water inside the tubes. Under certain conditions—such as a fixed circulating water temperature, circulating water volume, and steam load per unit area—a clean condenser will have a specific target value for the end difference. Generally speaking, as the circulating water volume increases, the cooling water outlet temperature decreases, and the end difference increases; conversely, if the circulating water volume decreases, the cooling water outlet temperature rises, and the end difference diminishes. Similarly, the greater the steam load per unit area, the larger the end difference will be, and vice versa. In actual operation, if the measured end difference significantly exceeds the specified target value, it indicates that the copper tubes on the condenser's cooling surface are fouled, leading to a deterioration in heat transfer performance.