Coal-water boiler exhaust gas residual heat recovery device

Abstract

A coal-water boiler exhaust gas residual heat recovery device is characterized in that a cyclic heat exchange system using water as the heat transfer medium separates a boiler exhaust gas cooler from a residual heat utilization device, thus avoiding the safety problem caused by heating surface leakage and simultaneously realizing seasonal change of the exhaust gas residual heat utilization device. Specifically, a gas cooler is arranged in a gas flue behind an air preheater (or dust catcher), the water is used as the heat transfer medium, firstly the water is heated in the gas cooler to reduce the exhaust gas temperature, and then the heat absorbed by the water in the gas cooler is released in another heat exchanger to be used for heating the main condensed water to raise the temperature of the low pressure feed water or heating the cold air to raise the inlet air temperature of the boiler. After the system is adopted, the boiler exhaust gas residual heat can be fully and effectively recovered, the steam extraction capacity of the heat regenerative system can be reduced, the generated output of the set can be increased and the coal consumption in power generation can be reduced.

Description

technical field [0001] The invention belongs to an energy-saving system for recovering and utilizing waste heat from boiler exhaust in a thermal power plant, and in particular relates to a device for recovering and utilizing waste heat from exhaust smoke of a water-medium boiler. Background technique [0002] Usually, for large-capacity bituminous coal boiler units, the design value of boiler exhaust gas temperature is usually about 125°C; for lean coal and anthracite boiler units, the design value of boiler exhaust temperature is usually about 140°C; The smoke temperature design value is usually as high as about 150°C. In the actual operation of the boiler, the actual exhaust gas temperature is often higher than the design value due to the deterioration of coal quality, the contamination of the heating surface and the accumulation of ash, and the leakage of the boiler. [0003] The design exhaust gas temperature of the bituminous coal boilers of domestic thermal power unit...

AI Technical Summary

Problems solved by technology

The existing uniformly distributed serpentine tube heat exchanger structure cannot make full use of this temperature gradient, which reduces the heat transfer efficiency and cannot make full use of the waste heat of the flue gas

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