SU1285263A1 - Method of recovering waste heat of boiler effluent gases - Google Patents

Abstract

The invention relates to heat engineering and can be used in fuel-burning installations. The purpose of the invention is to increase the thermal efficiency when placing in the gas duct between the steps (C) of the air preheater of the second C economizer. One part of the gas is withdrawn after the first C 2 along the gas flow, the other after the second C 3. Both these parts are fed through the recirculation pipeline 6 into the gas duct 1 between the first C 4 air preheater and the second C 3 economizer. The utilization of heat from waste gases is achieved by the redistribution of heat perception between them. As the amount of gases passing through step 4 is reduced, its aerodynamic resistance and ash wear decrease. 1 il. e C /) CX) sd GcE O5 co

Description

The invention relates to heat exchange technology and can be used in fuel combustion installations, such as boilers.

The purpose of the invention is to increase thermal efficiency when placed in a gas duct between the steps of an air preheater of a second economizer stage.

The drawing schematically shows a device that implements the proposed method.

The device contains successively installed in the gas duct 1 stage 2 and 3 water economizer and 4 and 5 air heaters. After the first stage 2 of the economizer, to the gas duct 1 is connected at one end a recycling pipe 6, the second end connected to the gas duct 1 in its zone after the first stage 4 of the air preheater. In pipe 6, a recycling exhaust fan 7 is connected, and a regulating gate 8 is installed before the latter. In addition, an additional recirculation pipe 9 with a gate 10 connected to the second end of the economizer and 5 air heaters of the connectors is connected to the zone of the gas duct 1 to the main pipeline 6 recirculation into its area between the gate 8 and the exhaust fan 7.

The device works as follows.

The flue gases through the flue 1 first flow into the first stage 2 along the gases in the economizer and then pass through the first stage 4 in the course of the gases of the air heater, the second 3 along the gases of the water economizer, the second stage 5 along the gases of the air heater and discharged into the chimney. In this case, one part of the gases is taken out after the first stage 2 along the gas of the water economizer, and the second part of the gases after the second stage 3 along the gas of the economizer, and both these parts of the exhauster 7 of the recirculation are fed through the pipeline recirculation together the first in the course of the gas stage 4 air preheater and the second in the course of the gas stage 3 economizer.

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The amount of gases taken for recirculation after the first and second stages 2 and 3 along the gas flow of the water economizer is controlled by gates 8 and 10 installed in the recirculation pipelines 6 and 9.

By recirculating some of the gases in the low temperature heating surfaces, namely, in some stages of the water economizer and air preheater, the heat transfer between them is redistributed. At the same time, more gases are passed through economizer stages 2 and 3 than through air preheater stages 4 and 5, which makes it possible to more efficiently use the heat of the boiler exhaust gases, and to intensify heat exchange in economizer stage 3. In addition, a decrease in aerodynamic resistance and ash wear is achieved in stage 4 of an air preheater, since the amount of gases passing through it decreases due to the removal of some of the gases after stage 2 of the water economizer and dumping them, stage 4 of the preheater, smoke exhauster 7 recycle to the zone of gas duct 1 before the second stage 3 along the gas flow of a water economizer.

Claims (1)

Invention Formula The method of utilization of heat from the boiler exhaust gases by supplying them through the water economizer and air preheater stages installed in the gas duct with the removal of the first part of these gases after the first economizer stage, bypassing the first air heater stage, in that increase of thermal efficiency when placed in the duct between the steps of the second stage heater of the economizer, the second part of gases is additionally taken from the zone of the duct between the second stages foams E economizer and air preheater and fed to it together with the first part in the flue gas between the first stage and the second stage air preheater economizer.