Combined-cycle combined heat and power system

Abstract

The invention provides a combined-cycle combined heat and power system, which comprises a steam turbine, an afterheat boiler and a heat network steam extraction system, wherein the steam turbine comprises a high-pressure cylinder, an intermediate-pressure cylinder and a low-pressure cylinder, the afterheat boiler comprises a high-pressure steam drum, an intermediate-pressure steam drum and a low-pressure steam drum, the three steam drums respectively generate three flows of steam, high-pressure steam, intermediate-pressure steam and low-pressure steam are respectively injected into the high-pressure cylinder, the intermediate-pressure cylinder and the low-pressure cylinder to apply work through expansion, and a generator is driven to output electric energy. A high-discharge check valve is arranged on a steam discharge pipeline of the high-pressure cylinder, and the heat network steam extraction system designed for heating is arranged at the downstream part of the high-discharge check valve and comprises two regulating valves in parallel connection, wherein the first regulating valve is connected with a first-stage temperature and pressure reduction device used for realizing the primary steam extraction regulation of the steam turbine, and the second regulation valve is connected with a pipeline arranged between an intermediate-pressure steam generator and an intermediate-pressure superheater through a cold reheating pipeline. Compared with a traditional combined cycle combined heat and power system, the combined-cycle combined heat and power system provided by the invention has the advantages that the operation efficiency is high, the generating efficiency is high, and high-quality energy source waste is little.

Description

technical field [0001] The invention relates to the technical field of gas-steam combined cycle and cogeneration of steam turbines, in particular to a combined cycle cogeneration system. Background technique [0002] Turbine generator set is an energy conversion device that converts thermal energy into mechanical energy and then into electrical energy, and is one of the key power equipment in the construction of power stations. The high-temperature and high-pressure steam generated by the boiler passes through the steam turbine to convert the thermal energy and the pressure potential energy into the mechanical energy of the steam turbine, which drives the output shaft of the steam turbine rotor to do work. Electric energy, therefore, the steam turbine as the source engine is often called "the source of light". [0003] The gas-steam combined cycle system refers to the use of the gas turbine as the front turbine, the waste heat boiler is used to recover the exhaust heat of t...

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Problems solved by technology

[0011] The design of combined cycle and combined heat and power generation system in the prior art is to set a rotating baffle or seat cylinder valve at about 1.8 MPa of the medium pressure cylinder of the steam turbine to realize adjustment and extraction of steam. The temperature of the steam here is about 460 °C, and the user The temperature requirement is only 285°C, and there is a waste of temperature difference of 175°C, which inevitably leads to waste of high-quality energy. At the same time, the setting of the adjustment mechanism destroys the medium-voltage flow structure, resulting in a decrease in the efficiency of the whole machine

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