A condensing steam turbine refers to a turbine where, after the steam expands and does work within the turbine, all but a small portion of the steam leaks out through the shaft seal, with the remainder entering the condenser and condensing into water.
During the process of the steam turbine exhaust cooling and condensing into water within the condenser, its volume suddenly shrinks, thereby creating a vacuum in the originally steam-filled enclosed space. This reduces the steam turbine exhaust pressure, increases the ideal enthalpy drop of the steam, and thus improves the thermal efficiency of the unit. The non-condensable gases in the steam turbine exhaust (mainly air) are extracted by a vacuum pump to maintain the necessary vacuum level.
The commonly used condenser for steam turbines is a surface condenser. The cooling water is discharged into a cooling pond or tower to be cooled before being recycled. For power plants near rivers, lakes, or reservoirs with sufficient water supply, the cooling water discharged from the condenser can be directly released into the river, lake, or reservoir, known as runoff cooling. However, this method may cause thermal pollution to rivers and lakes. In areas severely short of water, power plants can use air-cooled condensers. But they are large in structure, consume a lot of metal materials, and are rarely used in general power plants except for train power stations.
Comprised mainly of the turbine body, condensate pump, condenser, and circulating pump, it refers to the process where steam, after doing work within the turbine, enters the condenser where it cools and turns into liquid water, which is then returned to the boiler by the condensate pump.
The vacuum pump's function is to establish the necessary vacuum between the steam turbine and the condenser before the turbine starts up. During the operation of the condensing steam turbine, it continuously removes air and other non-condensable gases from the condensing equipment to ensure the heat exchange efficiency of the condenser's heat exchange tubes and maintain the vacuum level. The performance of the vacuum equipment directly determines the exhaust pressure of the condensing steam turbine, which in turn affects the size of the unit's enthalpy drop and the amount of steam consumed. Different vacuum extraction methods can impact the equipment investment cost, operational complexity, and system complexity of the steam turbine unit, making the vacuum pump equipment quite crucial for condensing steam turbines.
Performance Features
A condensing steam turbine unit is a multi-stage condensing steam turbine with high steam cycle utilization. It can extract steam for use in production processes or heating systems. The turbine's exhaust enters the condenser, where it condenses into water, which is then recycled back to the boiler for reuse. The pressure of the turbine's exhaust is below atmospheric pressure. It operates stably and is widely used in industries such as thermal power, oil, chemicals, dyeing, textiles, cement, sugar refining, and papermaking.
Structural Form: Quick-assembly, double-support, impulse multi-stage small steam turbine
Arrangement Style: Single or Double Layer
Speed Control System: Hydraulic Actuator with U.S. Company's 505 Digital Speed Controller, German Electro-Hydraulic Converter, and Siemens Technology.
Over-speed Protection: Two sets of mechanical fly hammer with electromagnetic valve and electronic intelligent control
Steam sealing form: stainless steel sheet labyrinth seal
Primary Steam Valve: Integrated Automatic Primary Steam Valve (Combination Regulating Valve)
Main shaft assembly: reversible speed impeller blades, sleeve-type rotor and impeller assembly, embedded blade impeller
Lubrication System: Forced oil lubrication, equipped with an oil tank, thin oil station, and cooler
Thermal Expansion Compensation: Front bearing support features sliding thermal compensation
Electrical Configuration: Complete control cabinets, protection cabinets, main control cabinets, and matching Siemens generators.
Wheeling Device: Electric Wheeling Machine
