Variable-rotation-speed turbine and heat supply system thereof

Abstract

The invention provides a variable-rotation-speed turbine. The variable-rotation-speed turbine comprises a high-and-intermediate-pressure cylinder and a low-pressure cylinder, wherein the high-and-intermediate-pressure cylinder is provided with a first rotor shaft, and the low-pressure cylinder is provided with a second rotor shaft. The variable-rotation-speed turbine further comprises a speed change mechanism. The output end of the speed change mechanism is connected with the first rotor shaft. The input end of the speed change mechanism is connected with the second rotor shaft. When the operation backpressure of the turbine rises, the steam enthalpy drop delta h of the low-pressure cylinder is reduced, and the speed change mechanism is used for reducing the rotation speed n of the second rotor shaft of the low-pressure cylinder. When the operation backpressure of the turbine lowers, the steam enthalpy drop delta h of the low-pressure cylinder is increased, and the speed change mechanism is used for increasing the rotation speed n of the second rotor shaft of the low-pressure cylinder. According to the variable-rotation-speed turbine, the rotation speed of the low-pressure cylinder of the turbine is changed through the speed change mechanism, the variation of the rotation speed of the low-pressure cylinder corresponds to the enthalpy drop variation, generated when the operation backpressure of the turbine changes, of the low-pressure cylinder, and therefore the speed ratio of the low-pressure cylinder is always within a reasonable design range; and in this way, safe operation of the turbine set is guaranteed, and the economical efficiency of the turbine set is also improved.

Description

technical field [0001] The invention relates to the field of steam turbine power generation, in particular to a variable speed steam turbine and a heat supply system thereof. Background technique [0002] In recent years, in order to meet the requirements of energy saving and emission reduction in my country, small back pressure heating units are usually shut down and replaced by high-power condensing units for centralized heating. In order to further reduce the loss of the cold source of the condenser and increase the heat supply, in winter heating conditions, some power plants use the return water of the heating network as the circulating water of the condenser, and the low-pressure exhaust steam of the steam turbine is directly heated for heat supply Pipe network circulating water. Since the return water temperature of the circulating water in the heating pipe network is generally 45-50°C, and the outlet temperature of the circulating water in the heating pipe network is...

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Problems solved by technology

[0004] Method 1: The operating back pressure of the steam turbine in the heating period is taken as the design point, and shorter blades are used. However, in the non-heating period, the blades of the steam turbine operate under blocking back pressure, and the economy is very poor

[0005] Method 2: Adopt interchangeable dual-pressure low-pressure rotor design to adapt to different operating back pressures. However, the cost is very high, and two sets of rotors suitable for different operating back pressures need to be equipped, and when the operating back pressure is high or low It is also inconvenient to replace the corresponding rotor when running back pressure

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