Flue gas waste heat utilization device and method of boiler water heat medium controlling circulating type air preheater

Abstract

The invention relates to the technical field of boiler flue gas waste heat utilization, in particular to a flue gas waste heat utilization device and a method of a boiler water heat medium controlling circulating type air preheater applicable to a power station boiler with a steam drum. The device comprises a boiler water heat medium controlling circulating type air preheater and a rear flue gas channel convection heating surface. The upper portion of the boiler water heat medium controlling circulating type air preheater is connected to a falling pipe through an inlet header of the air preheater and the lower portion passing through a circulating pipe is connected to a circulating pump with a frequency converter through an outlet header of the air preheater. The rear flue gas channel convection heating surface is arranged in a perpendicular flue, the lower portion is connected to the circulating pipe through an inlet header of the convection heating surface, and the upper portion of the rear flue gas channel convection heating surface is connected to a raising pipe through an outlet header of the convection heating surface. The inlet header of the convection heating surface is provided with a thermometric indicator. An automatic control device is arranged between the thermometric indicator and the circulating pump with a frequency converter. The device can effectively improve the boiler thermal efficiency.

Description

technical field [0001] The invention relates to the technical field of utilization of waste heat from boiler exhaust, in particular to a device and method for utilizing waste heat of flue gas of a boiler water heat medium control circulation type air preheater suitable for a utility boiler with a steam drum. Background technique [0002] The heating surface at the tail of the boiler usually adopts the structural form of an economizer plus an air preheater, which has the advantage of reducing the heat loss of the exhaust gas while preheating the air supply, increasing the furnace temperature, and improving combustion. But this traditional boiler tail heating structure has two disadvantages. First, the air preheater uses the flue gas to exchange heat directly through the metal heating surface and the air supply. Air leakage due to low-temperature corrosion, wear, or structural gaps is inevitable, which affects the output of the boiler and increases the power consumption of the...

AI Technical Summary

Problems solved by technology

Although the exhaust gas temperature can be greatly reduced after the transformation, even lower than the design value, the heat recovered due to the reduction of the exhaust gas temperature is used to heat the condensed water or demineralized water without exception, and squeeze out the low-heater or deaerator to extract steam into the steam turbine The work is done by low-quality steam with low useful energy, which leads to an insignificant increase in unit efficiency

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