Classification of steam turbines

The wide and diverse use of steam turbines in various sectors of the national economy has given rise to a variety of steam turbine designs

Steam turbines are one of the most efficient mechanisms invented by man over the past three hundred years. They are in demand, such units can be found in almost all areas of human activity. To improve performance, steam turbines are modernized. The classification tree of steam equipment is growing.

Turbines in transport

The power of steam heated to high temperatures has high energy and is traditionally used in transport.

On various ships, a steam turbine most often drives propellers. Such units, with compact dimensions and low weight, can generate high efficiency.

Turbines in industry

Turbines in industrial sectors of the economy help provide steam for a wide variety of technological processes. They can be found in enterprises that produce paper, fabric, rubber, cars, etc.

Auxiliary turbines are found as additional elements in various pumps, ventilation systems, etc. For stationary turbines, the issues of size and weight are not so relevant. The steam turbine has an additional meaning: it can change the rotation speed. It is connected to the generator drives, which contribute to the generation of electricity. Such massive units can most often be found at hydroelectric power plants. The main indicator of turbines installed at thermal power plants is a stable rotation speed.

Turbines at thermal power plants and nuclear power plants

Condensing turbines are responsible for the generation of electrical energy; they can be seen at large state district power plants and even nuclear power plants. Steam that has exhausted its potential in condensing units is removed to the condenser, there is a vacuum in it. Power turbines have heat extraction to heat the hydraulic circuits of their own units, and are also actively used to heat houses.

Cogeneration units generate heat and electricity. They are differentiated into mechanisms with backpressure and units with adjustable extraction. In steam engines created on the basis of backpressure, the generated steam is used for technological purposes. The steam strength varies at the output of 0.41-4.2 MPa. The electrical load of the turbine is directly proportional to the production of heat. The electrical load of turbines with backpressure depends on the production of heat. Units that have adjustable steam extraction operate at a pressure of 0.071-0.241 MPa, they are also called cogeneration units, since they help heat the water in the network to heat the residential sector.

Turbines differ in a number of criteria that allow them to be easily identified. There is also a special marking by which you can accurately determine the purpose of a particular unit.

Turbines in the electric power industry

There are units:

1. Basic;
2. Peak;
3. Semi-peak.

The first type can operate more than 5,500 hours a year, these modern high-tech units are distinguished by an excellent economy mode.

The second type of turbines is used as auxiliary devices. When additional energy is required on holidays or weekends. They can function no more than five thousand hours a year, their basic advantage:

• Mobility;
• Cheapness

Peak units can operate up to two thousand hours a year, they are connected when there is not enough electricity during peak hours (morning and evening).

Design differences

Turbines also differ in design characteristics:

1. Number of cylinders. In single-cylinder turbines, all blocks are arranged in one cylinder. There are also devices where such an arrangement is combined in several cylinders; All this makes it possible to obtain a higher efficiency at the output. Multi-cylinder units are more complex in design, they are more expensive.
2. There are also single-shaft and twin-shaft turbines. The former have one generator to which the rotors of the cylinders are attached, they are connected by couplings. Twin-shaft turbines have two rotors, they have two generators. They are not very common.

Turbine marking

The first letters characterize the type of unit:

• K – condensing turbine;
• T – with steam extraction using cogeneration technology (also a condensing device).

After the first letter, the unit capacity in MW (nominal and maximum) is indicated. Initial steam pressure before the unit shut-off valve. For turbines:

• P;
• PT;
• R

The nominal steam pressure, unit of measurement MPa, is placed below the line. Example:

K-206-14.8; P-12-4.5/0.8; P-6-8.7/0.6; PR-14/15-8.9/1.6/0.8; T-255/305-23.8; PT-62/77-12.8/1.28).

For units with low-power steam extraction, the design temperature of the cooling liquid is taken as 22 degrees Celsius. Reason: the turbine is mounted within the city or at an enterprise, where cyclic water supply is used (cooling towers).