A two-stage raw coal drying system and raw coal drying method suitable for air-cooling units

Abstract

The invention discloses a two-stage raw coal drying system and method applied to an air cooling unit and belongs to the field of power station energy conservation. The system is mainly composed of a boiler, a steam turbine, a condenser / an air cooling island, a regenerative heating unit, an electric generator, a cooling tower / an exhaust steam-circulation water heat exchanger, a two-stage raw coal drying unit and the like. In the air cooling unit burning middle and high moisture coal, raw coal enters the two-stage raw coal drying unit sequentially after the raw coal is broken through a coal breaker. Hot circulation water at the outlet of the condenser or at the outlet of the exhaust steam-circulation water heat exchanger and low-pressure extraction steam of the steam turbine serve as drying heat sources of the two-stage drying unit respectively to dry the raw coal. The raw coal fully dried is sent into the boiler to be burnt after the raw coal is milled through a coal mill. According to the two-stage raw coal drying system and method, the two-stage raw coal drying unit is arranged, waste heat of a power plant is fully used, and the moisture of coal entering the boiler can be reduced significantly; the energy density of the coal entering the boiler is increased, so that the burning efficiency of the boiler is improved and the equipment investment of a power station is reduced, and accordingly the heat efficiency and the economical efficiency of the air cooling unit are improved.

Description

technical field [0001] The invention belongs to the field of power station energy-saving equipment, and in particular relates to a two-stage raw coal drying system and a raw coal drying method suitable for an air-cooling unit. Background technique [0002] my country's primary energy is dominated by coal, and the proportion of coal in my country's primary energy consumption has been around 70% for a long time. The installed capacity and power generation of coal-fired power generation account for about 69% and 78% of the total installed capacity and total power generation of the country, respectively, and the consumption of raw coal accounts for about 50% of the total domestic coal consumption. In recent years, the National Development and Reform Commission, the Ministry of Environmental Protection, and the National Energy Administration issued the "Coal-fired Energy Conservation and Emission Reduction Upgrading and Transformation Action Plan 2014-2020" clearly pointed out th...

AI Technical Summary

Problems solved by technology

Common lignite drying methods include flue gas drying and superheated steam drying, but they need to consume a large amount of high-temperature flue gas and high-grade steam extraction respectively.

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