JP2001254928A - Heating device, and white smoking inhibition method of combustion exhaust gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To establish a technique for inhibiting white smoking that is generated when discharging a combustion exhaust gas to the fresh air while highly maintaining the amount of recovery of the heat of the combustion gas in a heating device 100 that is provided with a heat exchanger 6 for heating that exchanges heat between condensate being discharged from a radiator X and a combustion gas that is discharged from a burner part 4, a heat exchanger 26 for supplying hot water that exchanges heat between supplied water being equal to or less than the dew point of the combustion gas and the combustion gas being discharged from a burner 26 and also recovers the condensation latent heat of steam in the combustion gas by supplying water, and an exhaust gas channel 7 for discharging the combustion exhaust gas after exchanging heat to the fresh air. SOLUTION: An exhaust gas channel 7 is provided with a heat exchanger 10 for heating an exhaust gas that heats a combustion exhaust gas being circulated through the exhaust gas channel 7 using condensate before being supplied to a heat exchanger 6 for heating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heating heat exchanger for exchanging heat between combustion gas discharged from a burner and condensate discharged from a heating radiator, a combustion gas discharged from a burner and the combustion. A hot water supply heat exchanger for performing heat exchange with feed water having a dew point lower than the gas and recovering the latent heat of condensation of water vapor in the combustion gas also with the feed water, and exhausting flue gas after the heat exchange to the outside air A heating device having a flow path, further comprising a heat exchanger for recovering heat of the combustion gas discharged from the burner section, an exhaust gas flow path for discharging the combustion gas discharged from the heat exchanger to the outside air. The present invention relates to a method for suppressing white smoke from the combustion exhaust gas discharged to the outside air in the heating device provided.

[0002]

2. Description of the Related Art For ease of explanation, for example, in a home, in a heating radiator for circulating and radiating hot water such as a hot water floor heating system or a fan convector in a home, condensate discharged from the heating radiator is used. A heating device used as a heat source device for heating water and supplying the heated outgoing water to the radiator for heating will be described below.

In such a heating device, for example, the combustion exhaust gas having a temperature below the dew point in the exhaust gas channel is in a water vapor saturated state, and when the combustion exhaust gas in the water vapor saturated state is directly discharged to the outside air, it is rapidly cooled by the outside air. As a result, the water vapor in the combustion exhaust gas may be condensed to form white smoke. In particular, when the hot water supply heat exchanger is configured to recover the latent heat of condensation of water vapor in the combustion gas discharged from the burner section by the water supply below the dew point of the combustion gas,
The combustion exhaust gas discharged from the heat exchanger is already in a steam-saturated state, and if discharged directly to the outside air, a large amount of white smoke may be generated. Such white smoke itself is not harmful because it is a water drop, but if it is generated in large quantities, it will be mistaken for a fire or it will be perceived as emitting harmful gas, so make it difficult to see this white smoke Is preferred. As a method for making the white smoke less visible, reheating of the combustion exhaust gas by another heat source or the like or dilution with air has been performed.

[0004]

In the case of reheating in order to prevent white smoke, reheating is performed by another heat source such as a heater, or by hot water after heating for heating or hot water for hot water supply. Although a configuration in which heating is performed has been adopted, in any case, it causes heat loss. In the latter, since much of the recovered heat will be used for reheating, the amount of effective recovered heat will be small, and the outflow for heating or the supply of hot water will be reduced to a temperature that allows for heat release by reheating the combustion exhaust gas. The necessity of heating caused a further decrease in thermal efficiency.

In the above-described heating apparatus for hot water heating, when the radiator is started or when the radiator is operated at a low temperature,
The condensate temperature is relatively low.For example, in a heat exchanger for heating a combustion gas passage, steam in the combustion gas can be condensed to recover even the latent heat of condensation of the combustion gas. When the radiator for heating is in the rated operation state, the temperature of the condensate becomes warm as 40 ° C. to 60 ° C., and the heat can be recovered only from the combustion gas at least at the temperature of the condensate in the heating heat exchanger. Did not. Incidentally, the outgoing water temperature during the rated operation is from 60 ° C to 80 ° C.

Accordingly, an object of the present invention is to provide a technique for suppressing white smoke generated when exhausting combustion exhaust gas to the outside air while maintaining a high heat recovery amount of the combustion gas in view of the above circumstances. Is to do.

[0007]

The features, functions and effects of the heating device according to the first aspect of the present invention are as follows.

[Features] Heating heat exchanger for exchanging heat between the combustion gas discharged from the burner and the condensate discharged from the heating radiator, the combustion gas discharged from the burner and the combustion gas A heat exchanger for hot water supply that performs heat exchange with feed water having a dew point of not more than and recovers latent heat of condensation of water vapor in the combustion gas also by the feed water, and an exhaust gas flow for discharging combustion exhaust gas after the heat exchange to the outside air. A heat exchanger for heating the flue gas flowing through the flue gas passage by condensate before being supplied to the heating heat exchanger. Prepare for.

[Effects and Effects] A hot water supply heat exchanger is provided which circulates therein water supplied from a water supply pipe or the like and has a temperature equal to or lower than the dew point of the combustion gas and also recovers latent heat of condensation of water vapor in the combustion gas. In the heating device, the combustion exhaust gas discharged to the exhaust gas flow path on the downstream side is in a steam saturated state, and when the steam exhaust gas in the steam saturated state is directly discharged to the outside air, a large amount of white smoke is generated. Therefore, as in the present configuration, in a heating device including a heat exchanger for heating together with such a heat exchanger for hot water supply, a heat exchanger for exhaust gas heating is provided in an exhaust gas passage, and the combustion exhaust gas in a water vapor saturated state is provided. Heating can be performed by heat exchange with condensing water for heating, and the flue gas is released to the outside air after reducing the humidity of the flue gas, thereby suppressing flue gas of the flue gas.

[0010] Further, the condensed water whose temperature has been lowered due to heat deprived by the combustion exhaust gas in the exhaust gas heating heat exchanger is supplied to the most downstream side in the combustion gas flow path of the heating heat exchanger, and is again heated by the combustion gas. There is no substantial heat loss. The temperature of the condensate supplied to the heating heat exchanger is as low as about the dew point of the combustion gas, for example, about 50 ° C. when the fuel is natural gas city gas. The latent heat of condensation of the gas can also be recovered, and the thermal efficiency can be increased. Therefore, it is possible to configure a heating device capable of suppressing the flue gas of the combustion exhaust gas even if a heat exchanger such as a condensing type hot water supply that easily emits the flue gas is provided while maintaining high thermal efficiency. .

Further, such a hot water supply heat exchanger can be provided in a combustion gas flow path separate from the heating heat exchanger, but may also be provided in the same combustion gas flow path as the heating heat exchanger. If the same combustion gas flow path is provided, 40 ° C. to 60 ° C.
The apparatus can be configured so that latent heat of condensation of the combustion gas which cannot be recovered by condensing at a temperature as high as ° C. is recovered by supplying water having a temperature equal to or lower than the dew point of the combustion gas.

Features of the heating device of the present invention according to claim 2
The operation and effect are as follows.

[Features] In the heating apparatus according to the first aspect of the present invention, a dilution means for diluting the combustion exhaust gas with air supplied from outside air is provided in the exhaust gas passage.

[Operation / Effect] As in the present configuration, by providing the above-mentioned dilution means, the combustion exhaust gas heated in the exhaust gas heating heat exchanger is diluted with air by the dilution means to further reduce the humidity. Can be discharged into the open air,
White smoke of the combustion exhaust gas can be further suppressed. In the case of such a configuration, a heat exchanger for heating exhaust gas is used,
The air supplied from the outside air is heated by the dilution means, and the combustion exhaust gas can be heated and diluted by the heated air.Furthermore, the condensate for heating cooled by the dilution air is used for heat exchange for heating. And the latent heat of condensation of the combustion gas can be recovered by condensing. Therefore, it is possible to further suppress the whitening of the combustion exhaust gas and to configure a highly efficient heating device.

The features, functions and effects of the method for suppressing whitening of flue gas of the present invention according to claim 3 are as follows.

[Features] A heating apparatus comprising a heat exchanger for recovering heat of the combustion gas discharged from the burner section and an exhaust gas flow path for discharging the combustion gas discharged from the heat exchanger to the outside air. A method for suppressing whitening of flue gas discharged to the outside air, wherein the flue gas flowing through the flue gas passage exchanges heat with condensate discharged from a radiator for heating. Then, the mixture is heated and discharged to the outside air.

[Action and Effect] The flue gas that has recovered even the latent heat of condensation in the heat exchanger for hot water supply, the flue gas that has been deprived of heat in the flue gas passage and cooled, etc., are in a water vapor saturated state. There is. If the combustion exhaust gas in the water vapor saturated state is directly discharged to the outside air, a large amount of white smoke may be generated.
As in this configuration, the combustion exhaust gas flowing through the exhaust gas passage is
By reheating by exchanging heat with condensate for warm heating at around 40 ° C to 60 ° C to reduce humidity and discharge it to the outside air,
The flue gas discharged to the outside air hardly generates white smoke due to condensation of water vapor. In addition, the temperature of the condensate used for heating the combustion exhaust gas is about the dew point of the combustion gas, for example, about 50 ° C. when the fuel is natural gas-based city gas. Condensed latent heat can also be configured to be recovered by condensing water, thereby increasing thermal efficiency. Therefore, white smoke generated when exhausting the combustion exhaust gas to the outside air can be suppressed while keeping the heat recovery amount of the combustion gas high.

The features, operations and effects of the method for suppressing the whitening of combustion exhaust gas of the present invention according to claim 4 are as follows.

[Features] In the method for suppressing whitening of flue gas according to the third aspect of the present invention, the heat exchanger is a heat exchanger that also recovers latent heat of condensation of the combustion gas.

[Action and Effect] As in the present configuration, in a heating device provided with a heat exchanger that also recovers latent heat of condensation, the combustion exhaust gas discharged to the exhaust gas passage is in a steam-saturated state, White smoke is likely to be generated when discharged.However, in the exhaust gas channel, the exhaust gas is heated by condensing water for heating to reduce the humidity of the combustion exhaust gas. It is easy to exhibit the suppression effect.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] A first embodiment of a heating apparatus according to the present invention and a method for suppressing white smoke from combustion exhaust gas thereof will be described below with reference to the drawings. The heating device 100 shown in FIG. 1 is used as a heating heat source device circulating through a radiator X for hot water heating or the like, and further heats water supplied from a water supply pipe 15 to supply hot water to the curan Y. Tube 16
Are supplied via Specifically, the heating device 10
0 denotes a mixing section 1 for mixing the air supplied by the air fan 2 with the fuel gas of the natural gas-based city gas supplied by the fuel nozzle 3, and a burner section 4 for burning the air-fuel mixture of the mixing section 1. And a combustion gas passage 5 through which the combustion gas discharged from the burner section 4 flows. Further, the combustion gas flow path 5 includes a hot water supply heat exchanger for heating feed water by heat exchange with combustion gas flowing through the combustion gas flow path 5, and a heating water heater for heating condensing water for heating. A heat exchanger 6 in which the heat exchanger and the heat exchanger are integrally formed is provided. The condensed water discharged from the radiator X to the return path 13 is passed through the downstream-side heating heat exchanger 6b and the upstream-side heat exchanger 6a in order to perform heat exchange with the combustion gas to heat the condensed water. It is configured to supply water to the radiator X via the outward path 14. The return path 13 includes a tank 1 for expanding the heating water.
2 and a pump 11 for flushing the condensate water to the downstream side heat exchanger 6b. Further, the water supply at a low temperature and below the dew point of the combustion gas is first supplied to the downstream hot water supply heat exchanger 6c provided at the most downstream side of the combustion gas flow path 5, and the combustion gas is supplied to the downstream hot water supply heat exchanger 6c. The condensed latent heat is recovered by condensing the water vapor inside. Further, the feed water discharged from the downstream hot water supply heat exchanger 6c is supplied to the upstream heat exchanger 6a provided on the upstream side of the combustion gas flow path 5, and is circulated through the inside to be heated and then turned into hot water. It is supplied to Curran Y. In such a heating device 100, for example, when performing hot water heating for home use, the heating device 100
The temperature of the outgoing water flowing to the heating device 100 is about 80 ° C., and the temperature of the condensed water flowing from the radiator X to the heating device 100 is 60 ° C. in the rated operation.

The heating device 100 is provided with an exhaust gas passage 7 through which the combustion exhaust gas discharged from the combustion gas passage 5 flows, and is configured to discharge the combustion exhaust gas to the outside air through an exhaust port 8. ing. In such a heating device 100, the latent heat of condensation is recovered by the downstream-side hot water supply heat exchanger 6c, and the combustion exhaust gas discharged to the exhaust gas passage 7 is particularly in a steam-saturated state. May generate white smoke. Therefore, the heating device 100 of the present invention is configured to suppress the generation of white smoke, and its characteristic configuration will be described below.

The heating device 100 of the present invention includes a heat exchanger 1 for heating the exhaust gas near the exhaust port 8 on the downstream side of the exhaust gas channel 7.
0, and the heat exchanger 10 for heating exhaust gas is provided with a pump 1
Condensation for heating sent by 1 and exhaust gas channel 7
And heats the flue gas by condensing water at about 60 ° C. before being supplied to the heat exchanger 6 for heating, thereby heating the flue gas in a steam-saturated state. Then, after the humidity is reduced, the air is discharged to the outside air, so that the generation of white smoke can be suppressed.

Since the temperature of the condensate supplied to the downstream-side heating heat exchanger 6b has dropped to about the dew point of the combustion gas, water vapor in the combustion gas is removed by the downstream-side heating heat exchanger 6b. By condensing, the latent heat of condensation of the combustion gas can also be recovered, and the overall thermal efficiency can be improved.

[Embodiment 2] A second embodiment of a heating apparatus according to the present invention and a method for suppressing white smoke from combustion exhaust gas thereof will be described below with reference to the drawings. Heating device 100 shown in FIG.
Is used as a heat source device for hot water heating and supplies hot water to the curan Y similarly to the first embodiment. Although the description of the same configuration as that of the above embodiment is omitted, in the heating device 100, only the heating heat exchanger 6 is provided in the combustion gas flow path 5, and the heating heat exchanger 6 is The condensate formed by the upstream heat exchanger 6a on the upstream side of the flow of the combustion gas in the combustion gas flow path 5 and the downstream heat exchanger 6b on the downstream side, and discharged from the radiator X to the return path 13, It is configured to circulate through the downstream heat exchanger 6b and the upstream heat exchanger 6a in order to exchange heat with the combustion gas and heat, and to supply the heated outgoing water to the radiator X via the outgoing path 14. Have been. The return path 13 is provided with a tank 12 for expanding the heating water and a pump 11 for flowing the condensed water to the heating heat exchanger 6 side.

Separately, a mixing section 2 for mixing the air supplied by the air fan 22 with the fuel gas of the natural gas-based city gas supplied by the fuel nozzle 23.
1 and a burner unit 2 for burning the air-fuel mixture in the mixing unit 21
4 and a combustion gas passage 25 through which the combustion gas discharged from the burner section 24 flows. This combustion gas flow path 25 is provided with only a hot water supply heat exchanger 26, and the hot water supply heat exchanger 26 includes an upstream heat exchanger 26a on the upstream side of the flow of the combustion gas in the combustion gas flow path 5, A low-temperature feedwater supplied from the water supply pipe 15 is supplied to the downstream heat exchanger 26b, and the downstream heat exchanger 26b also collects the latent heat of condensation of the combustion gas. Then, the water is supplied to the upstream heat exchanger 6a to exchange heat with the combustion gas for heating, and the heated hot water is supplied to the curan Y through the supply pipe 16. Further, the combustion exhaust gas after the heat exchange in the combustion gas channel 5 and the combustion gas channel 25 is discharged to the same exhaust gas channel 7.

In such a heating device 100, particularly, latent heat of condensation is recovered in the fuel gas passage 25, and the combustion exhaust gas flowing through the exhaust gas passage 7 is in a saturated state of water vapor, and is directly discharged to the outside air. Although a large amount of white smoke may be generated, the flue gas flowing through the flue gas passage 7 is reheated by the condensate for heating at about 60 ° C. by the exhaust gas heating heat exchanger 10 which is a feature of the present invention. However, since the flue gas is reduced in humidity and discharged to the outside air, it is possible to suppress flue gas in the flue gas.

Further, in the exhaust gas passage 7, a dilution air port 1 communicating with the outside air is provided downstream of the heat exchanger 10 for heating the exhaust gas.
And a suction fan 18 downstream of the suction fan 18 for sucking the combustion exhaust gas from the exhaust gas channel 7 and the air from the dilution air port 17.
Is provided, and the combustion exhaust gas can be diluted with air and discharged to the outside air, and white smoke can be further suppressed. The means for diluting the combustion exhaust gas with air and discharging it to the outside air, such as the suction fan 18 and the dilution air port 17, is referred to as dilution means.

Further, the exhaust gas heating heat exchanger 10 heats the air supplied from the dilution air port 17 by the suction fan 18, mixes the heated air with the combustion exhaust gas, and forms the exhaust gas passage 7. It is also possible to heat and dilute the flowing combustion exhaust gas.

[Other Embodiments] <1> Another embodiment of the method for suppressing white smoke from flue gas according to the present invention will be described below with reference to the drawings. The heating device 100 shown in FIG. 3 is used only as a heating heat source device circulated through a radiator X for hot water heating or the like.
That is, a heating heat exchanger 6 is provided in the combustion gas channel 5, and the heating heat exchanger 6 includes an upstream heat exchanger 6 a on the upstream side of the flow of the combustion gas in the combustion gas channel 5, And a downstream heat exchanger 6b on the downstream side.
The condensate discharged to 3 is passed through the downstream heat exchanger 6b and the upstream heat exchanger 6a in order, exchanges heat with the combustion gas, and heats the water. It is configured to supply the heat to the radiator X.

The heating device 100 is provided with an exhaust gas passage 7 through which the combustion exhaust gas discharged from the combustion gas passage 5 flows, and is configured to discharge the combustion exhaust gas to the outside air through an exhaust port 8. However, the combustion exhaust gas flowing through the exhaust gas channel 7 is radiated by the wall surface of the exhaust gas channel 7 and the like,
By the time it reaches the outlet 8, it is cooled to a temperature below the dew point, becomes saturated with water vapor, and emits white smoke when discharged to the outside air. Therefore, in this method, the combustion exhaust gas immediately before being discharged from the exhaust port 8 by the exhaust gas heating heat exchanger 10 is heated to 60 ° C. before being supplied to the heating heat exchanger 6.
Since the combustion exhaust gas which has been heated by the degree of condensed water to reduce the humidity can be discharged to the outside air, the generation of white smoke can be suppressed.

<2> In the above embodiment, the condensate supplied to the exhaust gas heating heat exchanger 10 is used for heating the combustion exhaust gas.
The condensate supplied from the exhaust gas heating heat exchanger 10 to the heating heat exchanger 6b is preferably at a low temperature from the viewpoint of recovering the latent heat of condensation of the combustion gas. A condensate cooler that cools the condensate between the heat exchangers with outside air may be provided.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a heating apparatus and a method for suppressing white smoke from combustion exhaust gas of the present invention.

FIG. 2 is a schematic configuration diagram showing a second embodiment of a heating device and a method for suppressing white smoke from combustion exhaust gas thereof according to the present invention.

FIG. 3 is a schematic configuration diagram showing another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 4 burner part 5 combustion gas flow path 6 heat exchanger 7 exhaust gas flow path 10 exhaust gas heating heat exchanger 24 burner part 25 combustion gas flow path 26 hot water supply heat exchanger 100 heating device X radiator Y curran

Continuation of front page (72) Inventor Akira Enomoto 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka F-term in Osaka Gas Co., Ltd. (reference) 3K070 DA04 DA48 3L036 AA04 AA12 AC24 3L070 BB02 BB03 BC03 CC01 CC02

Claims (4)

[Claims] A heating heat exchanger for exchanging heat between the combustion gas discharged from the burner and the condensate discharged from the heating radiator; A hot water supply heat exchanger that exchanges heat with feed water having a dew point or less and recovers latent heat of condensation of water vapor in the combustion gas by the feed water, and discharges flue gas after the heat exchange to the outside air. A heating device comprising: an exhaust gas heating heat exchanger that heats combustion exhaust gas flowing through the exhaust gas channel by condensing water before being supplied to the heating heat exchanger, in the exhaust gas channel. Equipped heating device. 2. The heating apparatus according to claim 1, further comprising a diluting means for diluting the combustion exhaust gas with air supplied from outside air, in the exhaust gas channel. 3. A heating apparatus comprising: a heat exchanger for recovering heat of a combustion gas discharged from a burner portion; and a flue gas flow path for discharging the combustion gas discharged from the heat exchanger to the outside air. A method for suppressing whitening of flue gas discharged to the outside air, wherein in the flue gas flow path, the flue gas flowing through the flue gas flow path exchanges heat with condensate discharged from a radiator for heating. A method for suppressing white smoke from the combustion exhaust gas which is heated and discharged to the outside air. 4. The method according to claim 3, wherein the heat exchanger is a heat exchanger that also recovers latent heat of condensation of the combustion gas.