JPH06241415A - Low nox burning apparatus - Google Patents

Abstract

PURPOSE:To provide a burning apparatus with a lower amount of NOx in an exhaust gas by decomposing the NOx generated once. CONSTITUTION:This low NOx burning apparatus is provided with a mixing part 6 to mix a primary air and a fuel gas being supplied to a burner 2, a combustion chamber 3 to perform a burning with the burner 2, a fan 1 to supply a secondary air for combustion to the burner 2, a heat exchanger 4 to perform a heat exchange between the combustion gas and water, a water supply part 7 to supply water to the heat exchanger 4, an exhaust section 5 to exhaust the combustion gas, an electrolytic device 8 to perform an electrolysis of water to be supplied being branched off the water supply section 7 and a path 11 for a hydrogen gas which introduces the hydrogen gas generated on the negative pole side 10 of the electric decomposer 8 to the fan 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low NOx combustion device for use in a water heater for domestic use or small-sized business and a bath kettle with hot water supply.

[0002]

2. Description of the Related Art In recent years, the problems of global warming and environmental destruction have been highlighted, and there is an increasing demand for NOx reduction in combustion equipment related to these problems. As a countermeasure against this, for example, as shown in FIG. 3, in a combustion device in which the combustion chamber 3, the heat exchanger 4 and the exhaust part 5 are connected to the downstream portion of the fan 1, the water inlet part 7 of the heat exchanger 4 is connected to the water passage 9 as shown in FIG. To the tank 33 and heat the water in the tank with the heater 31.
Water supply passage 3 as secondary air containing a large amount of water vapor
There is known a method (Japanese Patent Application Laid-Open No. 4-6308) in which the flame reaction temperature is lowered and the amount of NOx generated is reduced by supplying the combustion gas from the combustion chamber 3 to the combustion chamber 3 through the fan 1.

[0003]

However, in the above-mentioned method, although the amount of NOx generated can be reduced to some extent, the NOx once generated cannot be decomposed and further reduced, so that NOx in the exhaust gas can be reduced. It was not enough to reduce the amount of NOx. The present invention solves such a conventional problem, and an object of the present invention is to provide a combustion device that decomposes NOx that has been generated once and has a low amount of NOx in exhaust gas.

[0004]

According to the present invention, there is provided a mixing section for mixing primary air and fuel gas to be supplied to a burner, a combustion chamber for performing combustion by the burner, a fan for supplying secondary air for combustion to the burner, A heat exchanger for exchanging heat between combustion gas and water, a water inlet portion for supplying water to the heat exchanger, an exhaust portion for exhausting combustion gas, and an electrolysis of water branched from the water inlet portion and supplied. The present invention relates to an electrolyzer and a low NOx combustion device including a hydrogen gas passage for guiding hydrogen gas generated on the negative electrode side of the electrolyzer to the fan.

In the present invention described above, it is preferable that the oxygen gas generated on the positive electrode side of the electrolyzer is guided to the mixing portion of the primary air and the fuel gas through the oxygen gas passage and sent to the combustion chamber. It is preferable because the amount of air required for combustion can be reduced and the operating noise of the fan can be lowered. Further, if a part of the water supplied to the electrolyzer is guided to the fan together with the hydrogen gas, water is added to the secondary air,
The combustion flame temperature decreases by the amount of heat of vaporization and heat capacity of water, and the lower the combustion flame temperature is, the smaller the NOx generation amount is. Therefore, the above-mentioned action can reduce the generation amount of NOx itself, which is preferable. Further, since a large amount of NOx is generated in the inner flame portion in the combustion flame and the area in the vicinity thereof,
It is preferable to supply the hydrogen gas to the downstream side of the inner flame portion of the combustion flame because NOx can be effectively decomposed.

[0006]

With the above-described structure, hydrogen gas is added to the secondary air and introduced into the combustion chamber, and NOx generated in the combustion chamber is decomposed by the reducing action of hydrogen gas. The quantity is reduced.

[0007]

EXAMPLES Examples of the present invention will be described below. FIG. 1 is a diagram showing a configuration of a low NOx combustion device according to an embodiment of the present invention. In the figure, a burner 2, a combustion chamber 3, a heat exchanger 4 and an exhaust unit 5 are sequentially provided on the downstream side of a fan 1, and the burner 2 includes a mixing unit 6 for mixing primary air and fuel gas 14. , And the water inlet part 7 is provided with a water passage 9 branched from this for supplying water to the electrolyzer 8. The hydrogen gas passage 11 for guiding the generated hydrogen gas to the fan 1 is provided on the negative electrode side 10 of the electrolyzer 8, and the oxygen gas passage 13 for guiding the generated oxygen gas to the mixing portion 6 on the positive electrode side 12. Is provided. A part of the water supplied from the water passage 9 to the electrolyzer 8 can be supplied to the fan 1 by the hydrogen gas passage 11.

In the above structure, the hydrogen gas generated on the negative electrode side 10 of the electrolyzer 8 can be supplied to the combustion chamber 3 together with the secondary air, the NOx once generated can be decomposed, and the NOx amount in the exhaust gas can be reduced. Can be reduced. Further, by guiding the oxygen gas generated on the positive electrode side of the electrolyzer 8 to the mixing portion 6, the amount of air supplied from the fan 1 for good combustion can be reduced, and the fan 1
It is possible to lower the driving sound of. Furthermore, a part of the water supplied to the electrolyzer 8 together with the hydrogen gas is blown by the fan 1
Since it is supplied to the secondary air, water is added to the secondary air to lower the combustion flame temperature, and the amount of NOx itself generated can be reduced.

FIG. 2 shows another embodiment of the present invention, which is shown in FIG.
2 is a perspective view showing a main part of a burner for supplying hydrogen gas and secondary air supplied from a fan 1 in the low NOx combustion device of FIG. 1 to a downstream side from an inner flame part of a combustion flame. The burner 2 is provided with a flame port 21 where a mixed gas A composed of fuel gas passing through the interior of the burner, primary air, and oxygen gas generated on the positive electrode side 12 burns, and on the downstream side of the flame port 21. A combustion flame 22 is formed. On the side surface of the burner 2, the mixed gas B of hydrogen gas and secondary air supplied by the fan 1 does not flow into the flame mouth portion 21, and the downstream side of the inner flame portion 23 of the combustion flame 22 (upper side in the figure). A guide plate 24 is provided so as to be supplied to the. With the above configuration, hydrogen gas can be supplied to the downstream side of the inner flame portion of the combustion flame in which a large amount of NOx is generated, NOx can be decomposed more effectively, and the amount of NOx in the exhaust gas can be reduced.

[0010]

According to the present invention, the hydrogen gas generated on the negative electrode side of the electrolyzer is sent together with the secondary air to the combustion chamber, and the NOx once generated is decomposed with the hydrogen gas, so that the amount of NOx in the exhaust gas is reduced. Will be reduced. In addition, if the oxygen gas generated on the positive electrode side of the electrolyzer is guided to the mixing portion of the primary air and the fuel gas, the amount of air supplied from the fan for good combustion is reduced, and the fan operation is reduced. It is possible to lower the sound. Further, if a part of the water supplied to the electrolyzer is introduced into the fan together with the hydrogen gas, the water is added to the secondary air, so that the combustion flame temperature is lowered,
The generation amount of Ox itself can be reduced, and the NOx amount in the exhaust gas can be greatly reduced together with the decomposition of NOx by hydrogen gas. Then, if hydrogen gas is supplied to the downstream side of the inner flame portion of the combustion flame, NOx can be effectively decomposed, and the NOx amount can be further reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a low NOx combustion device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a main part of a burner in a low NOx combustion device according to another embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a conventional low NOx combustion device.

[Explanation of symbols]

1 ... fan, 2 ... burner, 3 ... combustion chamber, 4 ... heat exchanger,
5 ... Exhaust part, 6 ... Mixing part, 7 ... Water entry part, 8 ... Electrolyzer, 9 ... Water passage, 10 ... Negative electrode side, 11 ... Hydrogen gas passage, 12 ... Positive electrode side, 13 ... Oxygen gas passage , 14 ... Fuel gas, 21 ... Flame mouth part, 22 ... Combustion flame, 23 ... Inner flame part,
24 ... Guide plate, 31 ... Heater, 32 ... Moisture supply passage, 33 ... Tank

Claims (4)

[Claims] 1. A mixing section for mixing primary air and fuel gas to be supplied to a burner, a combustion chamber for performing combustion by the burner, a fan for supplying secondary air for combustion to the burner, and heat exchange between combustion gas and water. For exchanging water, a water inlet for supplying water to the heat exchanger, an exhaust for exhausting combustion gas, an electrolyzer for electrolyzing water branched from the water inlet, and the electrolyzer. Low NOx combustor having a hydrogen gas passage for guiding hydrogen gas generated on the negative electrode side to the fan. 2. The low NOx combustion device according to claim 1, further comprising an oxygen gas passage for guiding oxygen gas generated on the positive electrode side of the electrolyzer to a mixing portion of the primary air and the fuel gas. 3. The low NOx combustion device according to claim 1, wherein a part of the water supplied to the electrolyzer is introduced into a fan together with hydrogen gas. 4. A guide comprising a guide for supplying hydrogen gas to the downstream side of the internal flame portion of the combustion flame together with the secondary air.
The low NOx combustion device according to 2 or 3.