Gas turbine variable-back-pressure transformation system for combined cycle power station

Abstract

The invention discloses a gas turbine combined cycle variable-back-pressure transformation system in the energy saving field of power stations. The system mainly consists of such parts as a gas compressor, a combustion chamber, a gas turbine, an afterheat boiler, an induced draft fan flue, an induced draft fan, an induced draft fan bypass flue, a smoke bypass baffle plate and a chimney. The induced draft fan flue and the induced draft fan bypass flue are arranged in a smoke outlet of the afterheat boiler; the smoke bypass baffle plate is arranged in the separation place of the two flues; the induced draft fan is arranged in the induced draft fan flue; the gas pressure in the afterheat boiler flue is adjusted by using a method for adjusting the power of the induced draft fan, so that the exhaust pressure of the gas turbine is changed; and when the bypass flue baffle plate is closed to one side of the induced draft fan flue, the induced draft fan flue is closed, and the outlet pressure of the afterheat boiler and the gas turbine can be totally recovered. Compared with a conventional combined cycle unit, under the same load, the intake and smoke discharge temperatures of the gas turbine are increased, and the top cycle efficiency and the bottom cycle efficiency are optimized. The gas turbine combined cycle variable-back-pressure transformation system can optimize the operation economy of combined cycle under the working condition of part loads, prominently improves the peak shaving performance, and is prominent in economic benefit.

Description

Technical field [0001] The invention belongs to the field of power station energy saving, and particularly relates to a gas turbine variable back pressure retrofit system that can be used in combined cycle power stations. Background technique [0002] Gas turbines and their combined cycles have been used in the power generation industry since the 1950s; gas-steam combined cycle units often operate under partial load conditions due to their participation in the peak shaving of the power grid. However, as the gas turbine load decreases, its thermal efficiency Corresponding reduction, therefore, in-depth study of the performance of the combined cycle under all operating conditions has important theoretical and practical significance for the thermal economy of the unit. [0003] The methods currently applied to improve the efficiency of combined cycle under variable conditions mainly include three types of methods: variable geometry adjustment, operation strategy adjustment and system ...

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Problems solved by technology

[0006] Aiming at the problems that the thermal efficiency of the gas turbine combined cycle variable working condition is low, and the IGV cannot be fully used to adjust the intake air volume of the compressor when the unit adopts the equal T3 adjustment strategy, the invention proposes a gas turbine transformer that belongs to the field of power station energy saving and can be used in the combined cycle power station. The back pressure retrofit system adjusts the turbine exhaust back pressure of the unit under variable operating conditions by arranging an induced draft fan at the tail flue of the waste heat boiler, expands the operating range of the unit adjusted by equal T3, and improves the thermal efficiency of the combined cycle. The induced draft fan bypass flue in parallel with the induced draft fan flue can flexibly adjust the flue gas channel when the induced draft fan is in operation and not in operation, reducing the resistance loss of the flue

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