Gradient utilization method for flue gas of 1000MW secondary reheating power plant

Abstract

The invention relates to a gradient utilization method for flue gas of a 1000MW secondary reheating power plant. The method comprises the following steps: arranging a flue gas bypass on a boiler air preheater, and arranging two stages of high-energy-level low-temperature coal economizers, namely, a first low-temperature coal economizer and a second low-temperature coal economizer, on the flue gasbypass, wherein the first low-temperature coal economizer is used for heating feedwater, and the second low-temperature coal economizer is used for heating condensed water; and arranging a third low-temperature coal economizer at an inlet of a flue dust remover at the tail of an outlet of the boiler air preheater, wherein the third low-temperature coal economizer is used for heating cold air at aninlet of the air preheater through circulating water, so that the capacity of the high-energy-level low-temperature coal economizers is increased to the maximum extent. The condensed water, cold airand feedwater are heated at the same time through waste heat of boiler exhaust smoke, then the energy level of low-temperature smoke is improved, the utilization efficiency of the waste heat is greatly improved, the standard coal consumption of the unit is further reduced, so that the purposes of energy conservation and emission reduction are achieved, and meanwhile, the heat economy of the unit is improved.

Description

technical field [0001] The invention belongs to the technical field of thermal power generation, and in particular relates to a cascade utilization method for flue gas of a 1000MW secondary reheat power plant. Background technique [0002] With the rapid development of my country's economy, the demand for electricity is increasing year by year, and more and more large-scale coal-fired thermal power generating units are put into use, which also makes the supply of coal resources increasingly tight. The power generation efficiency of generator sets and the reasonable and effective use of limited coal resources are particularly important. [0003] Power plant boilers are the most energy-consuming equipment in power plants, and are also the source of a series of energy-consuming processes in power plants. In order to generate the steam driven by the prime mover for power generation and ensure a large working capacity, the power station boiler consumes a large amount of coal reso...

AI Technical Summary

Problems solved by technology

[0005] At present, the existing flue gas waste heat utilization scheme in power plants is mainly to install low-temperature economizers at the inlet of the dust collector and the outlet of the induced draft fan in the tail flue of the boiler. ℃, the recovered flue gas waste heat generally replaces the last few stages of the steam turbine recuperation system with low-pressure steam extraction, which can reduce the standard coal consumption of the unit by about 1-2g / kw.h, and the energy level of flue gas waste heat utilization is low