Condensing steam turbine The commonly used condenser is of the surface type. The cooling water is circulated and reused in cooling towers. At power plants located near rivers and lakes, if water resources are abundant, the discharged water can be directly released into these bodies of water—this practice is known as runoff. However, such a practice may cause thermal pollution to rivers and lakes. In regions experiencing severe water shortages, power plants can employ air-cooled condensers. Yet due to their bulky structure and high consumption of metallic materials, they are rarely used in conventional power plants except for mobile power stations. Some older power plants have adopted hybrid condensers, in which steam turbines come into direct contact with water. However, since the condensate from the exhaust steam becomes contaminated, it must undergo treatment before it can be used as boiler feedwater; thus, this method is now seldom employed.

Condensing steam turbine Due to the large amount of condensate generated, this system is generally best suited for use in locations with abundant water resources. If used in areas with water scarcity, air cooling would be required, which would significantly increase the volume of the air-cooled condenser, making it more challenging to install and requiring higher equipment investment. The primary function of this system is to establish and maintain the necessary vacuum level within the exhaust chamber, allowing steam to expand inside the turbine to a lower pressure. This increases the available enthalpy drop, enabling more thermal energy to be converted into mechanical work. Additionally, the condensed water can be heated and pressurized to serve as boiler feedwater, thereby reducing costs. Moreover, the system features deaeration capabilities. Furthermore, it acts as a steam collector for the entire thermal system, receiving bypass steam during unit startup and shutdown, recovering condensate, and discharging various types of water.

To ensure that steam operates within the unit under conditions of as high a vacuum as possible, both the main body and the vacuum system must exhibit exceptional sealing performance to prevent air leakage, which could compromise heat transfer efficiency, reduce vacuum levels, and contaminate condensate. However, achieving complete airtightness between the main body and the vacuum system is impossible; therefore, vacuum equipment (such as vacuum pumps) must be installed to continuously remove any air that leaks in. Secondly, the water-side sealing must be robust to prevent condensate from deteriorating due to infiltration by circulating water. This is particularly critical for large-scale units with stringent water quality requirements.

Condensing steam turbine Work Guidelines

It mainly consists of the main body, condensate pump, condenser, and circulating water pump. After performing work, the working fluid transitions from a gaseous state to a liquid state and is then pumped back to the boiler via the condensate pump. Among these components, the condenser plays a critically important role. Its primary purpose is to enhance thermal efficiency. This process involves converting the working fluid into liquid form, which significantly reduces its volume, creating a vacuum in the remaining space and thereby increasing the ideal enthalpy. During startup, the fluid undergoes throttling; the impeller of the regulating stage is pushed through the nozzle. After throttling, entropy increases, enthalpy decreases, leading to a rise in temperature after work is performed. The entire startup process consumes energy before grid connection and power generation begins.

With the widespread use of equipment, manufacturers have made numerous design choices. Improper startup procedures can easily damage the equipment, disrupt normal operation, reduce work efficiency, and shorten its service life.