Heating steam-extraction and heating-supply system adopting high-back-pressure small steam turbine

Abstract

A heating steam-extraction and heating-supply system adopting a high-back-pressure small steam turbine mainly comprises an intermediate-pressure cylinder, a low-pressure cylinder, the high-back-pressure small steam turbine, a peak-load calorifier, a front calorifier, an asynchronous generator, a drainage pump, an electric gate valve, an electric control valve, an electric butterfly valve, a circulating water pump, a heat supply network water supply pipe and a heat supply network return water pipe. The system is mainly used for turbine heating steam extraction heating supply reconstruction projects at the capacity level of subcritical 300 MW or above. High-quality steam pumped through a low-pressure communicating pipe passes through the high-back-pressure small steam turbine to do work; the steam enters the front calorifier to heat circulating water of a heat supply network after being depressurized. During the heating period, the high-back-pressure small steam turbine is made to operate at full load as far as possible, and the requirements for adjustment of changes of heating load are met by adjusting the peak-load calorifier. The circulating water of the heat supply network enters the front calorifier and the peak-load calorifier in sequence through the heat supply network return water pipe, is heated and then is supplied to heat consumers through the heat supply network water supply pipe. By means of the system, the power generation capacity of a unit is improved, gradient utilization of energy is realized, and the system has good economy and operating flexibility.

Description

technical field [0001] The invention belongs to the technical field of energy-saving of thermal power plants, and is directly applied to the renovation project of subcritical 300MW and above steam turbines for heating extraction and heating supply, so as to realize cogeneration of heat and power and improve the cycle efficiency of the unit. Background technique [0002] At present, the main domestic heating extraction and heat supply transformation scheme is to drill holes in the medium and low pressure connecting pipes of the steam turbine, lead the medium pressure cylinder exhaust steam into the heating network heater to heat the circulating water of the heating network to achieve external heating. The transformation plan is simple to implement for steam turbines with a capacity of 200MW and below, and the initial investment is small. There are already a large number of mature cases in China. High (above 0.7Mpa, far greater than the steam pressure 0.2-0.3MPa required by th...

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Problems solved by technology

[0003] The invention provides a high back pressure small steam turbine heating and steam extraction heating system. The system can generate a certain amount of electricity while ensuring that the heating and steam extraction and heating supply requirements are met, and solves the problem of steam exhaust in the medium pressure cylinder of steam turbines with a capacity of 300 MW and above. Waste of high-quality steam caused by direct external heating after decompression

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