Power plant fire coal steam extraction drying and waste heat using integrated system

Abstract

The invention relates to a power plant fire coal steam extraction drying and waste heat using integrated system. A steam drying machine steam inlet is connected with a turbine steam extraction opening, a steam drying machine condensation water outlet is connected with a deaerator, raw coal firstly enters a steam drying machine, and a steam drying machine drying coal outlet is connected with a boiler fuel inlet; drying dead steam of a brown coal drying system is connected into a waste heat recovering system, and the waste heat recovering system comprises a first-stage dead steam cooling device,a second-stage dead steam cooling device and a third-stage dead steam cooling device; the first-stage dead steam cooling device, the second-stage dead steam cooling device and the third-stage dead steam cooling device are sequentially connected, stair waste heat for dead steam drying is used for gradually heating turbine regenerative system condensation water, heating boiler wind feeding air andsupplying heat an external heat supply network; and combined heat and power generation of brown coal is achieved, meanwhile, the boiler efficiency is improved, and the obvious energy saving and environment benefits are achieved.

Description

technical field [0001] The invention belongs to the field of coal-fired thermal power generation systems, and relates to a method and system for pre-drying high-moisture lignite. Background technique [0002] Lignite is a low-metamorphic coal, a low-quality coal with the characteristics of high moisture and low calorific value. At present, in most lignite power plants, lignite with a moisture content of 30% to 50% is not pre-dried, but is directly in contact with the high-temperature flue gas extracted from the furnace in the coal mill to achieve the purpose of drying, and the flue gas used for drying And the water vapor produced by drying is sent into the furnace together with the pulverized coal, resulting in a decrease in furnace temperature, poor combustion stability, increased flue gas volume, a corresponding increase in furnace cross-sectional area and volume, and increased boiler manufacturing and installation costs. At the same time, the exhaust heat loss increases,...

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Problems solved by technology

In this system, on the one hand, a large number of steam turbines are required to extract steam, so that the work of the steam turbines is reduced; on the other hand, the latent heat of vaporization of the water vapor in the dry tail gas cannot be completely recovered, and the excess part is emptied, resulting in a waste of energy

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