FI108810B - Plant and method for streamlining combustion and heat transfer - Google Patents

Abstract

The invention concerns equipment and a method for enhancing the combustion event and heat transfer in a heating boiler. According to the invention, the space above the major combustion zone in the combustion space of the heating boiler is equipped with sound sources, which are used to generate an acoustic field to enhance the combustion event and to achieve more complete combustion.

Description

108810

Apparatus for Improving the Incineration and Heat Transfer Processes of the Combustion Process and Heat Transfer 5

The invention relates to an apparatus for enhancing the combustion process and heat transfer in a boiler according to the preamble of claim 1.

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The invention also relates to a method for enhancing the combustion process and heat transfer in a boiler according to the preamble of claim 8.

The invention relates to the combustion of power plants, heating furnaces, boilers and the like in the combustion chamber and to the improvement thereof. These embodiments of the invention will hereinafter be referred to as a boiler.

Combustion is a complex event that depends on a number of factors such as the particle size of the fuel, the combustion temperature and the design of the boiler.

; 20 The fuel used in the combustion event is oxidized to produce; heat. At typical combustion temperatures, the burning of a hot solid ·; ··· depends on the rate at which oxygen diffuses to the surface of the substance. As combustion progresses, the particle size and particle mass decrease. Combustion of coal results in the production of carbon monoxide, which is further converted into carbon dioxide.

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It is known to promote a combustion event by causing turbulence in the combustion space, which promotes the transfer of material and heat transfer during combustion. However, the known solutions still have problems in completing combustion in power plants, heating furnaces and boilers and the like. Tur-: 30 bulldozers, such as mixers, are difficult to bring to high temperatures, • · * 2 108810, typically 600-1000 ° C. In particular, there are problems with the combustion of non-volatile carbon particles.

The promotion of combustion also involves the cleaning of the heat transfer surfaces of the boiler from ash particles and non-combustible carbon particles. A known cleaning method is acoustic cleaning, in which sound sources are placed in the heat-transfer sections of the boiler and the sound is produced periodically at intervals of about 2 to 15 minutes every few seconds. Acoustic cleaning devices are known e.g. WO-82/01328 and WO-82/03803. In addition, U.S. Patent No. 5,785,012 discloses enhancing the combustion process and heat transfer in a boiler by providing sound sources above the main combustion zone of the boiler fire.

It is an object of the invention to provide an apparatus and method for promoting a combustion event such that combustion is more complete and emissions are reduced.

The apparatus according to the invention is essentially characterized by what is set forth in the characterizing part of claim 1.

The process according to the invention, in turn, is characterized by what is precursor; as defined in the characterizing part of claim 8.

· ·: The refrigerated combustion event of the invention is promoted in a boiler: by applying a rotating sound field to the space above the main combustion zone. The volatiles at this location are mainly already burned, but some of the carbon is still not burnt as small particles. The sound field is preferably continuous and is generated by suitable sound sources disposed on the boiler fires. More heat is produced and less waste is generated as a result of the combustion process, which also results in cleaner * * »• · *. ·.: combustion, which results in less harmful emissions.

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In the following, the invention will be described with reference to the accompanying drawings, in which the embodiments shown are not intended to be limiting.

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Figure 1 shows a boiler and the installation of the apparatus according to the invention.

Figure 2 shows an example of a sound field according to the invention.

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Figure 1 schematically shows a boiler applying the method of the invention for promoting a combustion event. Sound sources S are located in the combustion chamber 11 of the boiler 10. The sound sources S are located above the main combustion zone before cooling the flue gases. The sound source is preferably 15 horns, known from acoustic cleaning, which produce a volume of 100-165 dB at a frequency of 20-1000 Hz. Because of the good penetration depth, the selected sound frequency range is advantageous for use in promoting the combustion event. The power and frequency of the sound sources S can be adjusted within the selected range according to the type and size of the boiler and the location of the sound sources S • · · 20. The volume of the sound is selected such that the sound: pressure level generated by the sound sources S is preferably at least 120 dB at the meeting point of the sound pressure patterns.

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·; ··· The sound sources S are placed in the combustion chamber 11 so that the sound pressure produced by them: ": the defects meet at angles of 20-90 ° laterally and / or vertically.

In a preferred embodiment of the invention, the sound sources S are disposed at different heights of the boiler 10 and in the combustion chamber 11 as the frequency of the sound source S is increased, as the solid particles diameter and mass decrease in the combustion chamber 11. In this case, the desired effect of the combustion event: remains optimal.

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In another preferred embodiment of the invention, the sound sources S are placed in the boiler 10 so that the resulting sound field is rotatable. Figure 2 illustrates such a rotating sound field produced by placing four 5 sound sources S in the combustion chamber 11 of a rectangular diameter boiler 10 to produce the sound pressure directional pattern shown in Figure 2. A similar rotating sound field can also be generated in another form of boiler. The number and arrangement of the sound sources S may vary from that shown in this example when creating a rotating sound field.

In a preferred embodiment of the invention, through the sound sources S located in the boiler 10, a portion of the secondary and / or tertiary air required for the combustion event is supplied to the boiler 10. This supply air also acts as cooling air for the sound sources S.

The invention can be applied to all types of power plants, heating furnaces, boilers and the like. The sound source is known as horns known for acoustic cleaning, but other types of sound sources can also be used.

The claims which follow are not intended to be limited solely by the various embodiments of the invention. 1 • »* · ·

Claims (8)

5 108810 An apparatus for enhancing the combustion process and heat transfer in a boiler comprising sound sources (S) located above the main combustion zone 5 of the combustion chamber (11) of the boiler (10) for generating a combustion event and a more complete combustion sound field, characterized in that ) is arranged such that the sound pressure patterns generated by the sound sources (S) meet at 20-90 ° at lateral and / or elevation angles and that the sound sources (S) are arranged in the boiler (10) so that the resulting sound field is rotatable. 10 Apparatus according to claim 1, characterized in that the sound field generated by the sound sources (S) is continuous. j Apparatus according to claim 1 or 2, characterized in that the sound pressure level generated by the sound sources (S) is at least 120 dB at the meeting point of the sound pressure patterns. Apparatus according to one of claims 1 to 3, characterized in that : The frequency of the sound emitted by the sources (S) is 20-1000 Hz. ·: ··! 20: 5. Apparatus according to any one of claims 1 to 4, characterized in that the secondary and / or tertiary air or part thereof of the boiler (10) is supplied to the boiler by means of sound sources (S). • · · • · · Apparatus according to one of Claims 1 to 5, characterized in that the sound sources are located in the boiler (10) so that the sound frequency rises towards the upper part of the boiler (10). • · Apparatus according to any one of claims 1 to 6, characterized in that the sound sources (S) are acoustic horns. »I ► · I * · ·» I 6 108810 A method for enhancing the combustion process and heat transfer in a boiler, wherein the sound source (S) generates a sound field above the main combustion zone of the furnace (10) of the boiler (10), characterized by: rotating sound field. 1 «·« »· • ♦ ♦ • · * · • ·» • »*» »· · 7 108810