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 rest entering the condenser to condense into water.
In the process of steam condensing into water within the condenser, the volume of the steam rapidly shrinks, creating a vacuum in the sealed space originally filled with steam. This reduces the exhaust pressure of the steam turbine, increases the ideal enthalpy drop of the steam, thereby enhancing the thermal efficiency of the unit. Non-condensable gases in the 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-type. The cooling water is discharged into a cooling water pool or tower to be cooled before being recycled. For power plants located 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 lacking water, an air-cooled condenser can be used. But it is structurally large and consumes a lot of metal materials, so it is rarely adopted by general power plants except for train power stations.
Comprised mainly of the turbine body, condensate pump, condenser, and circulating water pump, it refers to the process where steam, after doing work within the turbine, enters the condenser to cool and turn into liquid water, which is then pumped back to the boiler by the condensate pump.
The vacuum pump's function is to establish the necessary vacuum between the turbine and the condenser before the turbine starts up. During the operation of a condensing turbine, it continuously extracts 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 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, complexity of operation, and system complexity of the turbine unit, making the vacuum equipment quite crucial for condensing 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 a condenser, where it condenses into water, which is then recycled back to the boiler for heating. 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 production, and papermaking.
Structure Type: Quick-installation, Double-bearing, Impulse Multistage Small Steam Turbine
Arrangement: Single-layer or double-layer
Speed Control System: Hydraulic actuator with a 505 digital speed controller, German electro-hydraulic converter, and Siemens technology.
Over-speed Protection: Two sets of mechanical hammer-type with electromagnetic valve electronic intelligent control
Gasket Type: Stainless Steel Plate Mosaic Gasket
Primary Steam Valve: Integrated Automatic Primary Steam Valve (Combination Regulating Valve)
Main shaft assembly: Variable speed impeller blades, sleeve fit assembly of the rotor and impeller, blade type is for insertion
Lubrication System: Forced oil lubrication, equipped with oil tank, thin oil station, and cooler.
Thermal Expansion Compensation: Front bearing support with sliding thermal compensation
Electrical Configuration: Complete control cabinets, protective cabinets, main control cabinets, and matching Siemens generators.
Wheeling Device: Electric Wheeling
