JP2000346455A - Combustion equipment having latent heat recovery heat exchanger with drain neutralizing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate occurrence of clogging or aging performance deterioration of a solid neutralizer due to adherence of a corrosion product by providing a means for intermittently automatically supplying chilled water or warm water to a neutralizing unit. SOLUTION: When a combustion is started, generated drain is introduced to a neutralizing unit 10 through a drain tube 7, reacted with a solid neutralizer, neutralized, and discharged out of a combustor as drain water having a pH of 5 to 9. A corrosion product generated by an aluminum alloy second stage heat exchanger 4 is also conveyed by the drain, introduced to the unit 10, and adhered to a surface of the solid neutralized material or gaps among neutralizer particles. Then, the chilled water is automatically poured once or a plurality of times to the unit 10 in a short time merely at each lapse of the time periodically, that is, irrespective of during combustion or during stopping of combustion by using a cleaning water tube 12 branched from a chilled water supply tube 2 or irregularly, for example, at each lapse of a certain integrated combustion time, and an adduct is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for burning combustible gas, petroleum liquefied gas or city gas obtained by separating from natural gas or methane hydrate using a combustion device provided with a latent heat recovery heat exchanger. The present invention relates to a gas combustion device provided with a device for neutralizing an acidic drain of exhaust gas generated at the same time.

[0002]

2. Description of the Related Art A combustor provided with a latent heat recovery heat exchanger has been applied to various types of household or industrial water heaters. FIG. 3 shows a general configuration example of such a water heater. City gas or the like is burned in the burner 2, and the generated combustion heat is consumed to heat water to a predetermined temperature in the first-stage heat exchanger 3, but excess combustion heat is consumed by the first-stage heat exchanger 3. It is used for heating the water in the heat transfer tubes in the second stage heat exchanger 4 disposed above.

When the flue gas exchanges heat with the cold water in the heat transfer tube in the second stage heat exchanger 4, not only the sensible heat of the flue gas but also the latent heat of the water vapor in the flue gas is recovered, resulting in high heat exchange. Efficiency is achieved. As a result of latent heat recovery,
The water vapor in the exhaust gas is condensed to form water droplets 5, and the water droplets are collected to form a drain. The drain absorbs sulfur oxides, nitrogen oxides, and the like in the exhaust gas and has a strong acidic liquid having a pH of about 3. It has become.

If the highly acidic drain is discharged as it is, it causes environmental problems such as corrosion of metal products used in drainage pipe systems, deterioration of concrete buildings, and water pollution. It is necessary to perform a neutralization treatment so as to conform to the range of PH5-9 specified in the above.

Conventionally, as a method of neutralizing drain, a second method has been used.
A saucer 6 is disposed below the stage heat exchanger 4 to collect water droplets 5, and for example, an alkaline solid neutralizing agent such as magnesium oxide or a calcium alloy is placed inside or outside the combustor as shown in FIG. A technique has been proposed in which a filled neutralizer 10 is provided, and a drain is guided to the neutralizer 10 through the drain pipe 7 to perform a neutralization treatment (for example, Japanese Patent Application Laid-Open No. 60-97094).
issue).

However, in the neutralization treatment method using a solid neutralizing agent as described above, there is a problem such as clogging due to deposits on the surface of the neutralizing agent particles due to long-term use, and deterioration over time. After a period of use, replacement or replenishment with a new neutralizing agent is necessary to cause the occurrence. Particularly in practical use, in order to improve the heat transfer efficiency in the second-stage heat exchanger 4, aluminum or an aluminum alloy having excellent heat conductivity is often used as a heat exchanger manufacturing material, and aluminum is corroded by acid drain. In addition, the performance of the neutralizing agent is significantly deteriorated due to the adhesion of corrosion products.

[0007]

SUMMARY OF THE INVENTION According to the present invention, when the material of the heat exchanger is aluminum or an aluminum alloy as described above, clogging of the solid neutralizing agent due to the adhesion of corrosion products and time-dependent It is an object of the present invention to provide a gas combustion device equipped with a drain neutralization device that does not cause performance degradation.

[0008]

According to the present invention, the above-mentioned object is attained by intermittently automatically supplying cold water, hot water or hot water to a neutralizer filled with a solid neutralizer.

That is, the present invention relates to a combustion apparatus provided with a latent heat recovery heat exchanger made of aluminum or an aluminum alloy, which comprises a neutralizer filled with a solid neutralizing agent and an exhaust gas generated in the latent heat recovery heat exchanger. A combustion apparatus comprising: means for collecting and introducing drain to the neutralizer; and means for automatically supplying cold or hot water to the neutralizer intermittently.

The means for automatically supplying cold or hot water to the neutralizer intermittently includes connecting a water supply pipe or a hot water supply pipe having an open / close valve to the neutralizer, and controlling the opening and closing of the valve by a program. It is an invention of a combustion apparatus characterized by comprising a vessel.

As described above, the substance causing the adhesion or clogging was found by analysis to be a product of corrosion of aluminum or aluminum alloy. The corrosion product is colloidal and soft at the beginning of the formation, but gradually becomes hard as an insoluble precipitate over time after adhering to the surface of a solid neutralizing agent such as magnesium oxide. Therefore, by intermittently supplying cold water or hot water while the corrosion product is soft, it is removed by the flushing action of running water, thereby eliminating deterioration and clogging of the neutralizing agent.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a combustion apparatus according to the present invention will be described with reference to FIG. FIG. 1 shows an embodiment in which drain generated in an aluminum alloy latent heat recovery heat exchanger is guided to a small neutralizer installed in a combustion device, neutralized in the combustion device, and discharged. It is an important section sectional view shown. When the combustion is started, the generated drain is introduced into the neutralizer 10 through the drain pipe 7, reacts with the solid neutralizer 11, is neutralized, and is discharged out of the combustor as PH5-9 discharge water. .

The corrosion products generated in the aluminum alloy second-stage heat exchanger 4 are also conveyed by drain and are discharged by the neutralizer 1.
0, and adheres to the surface of the solid neutralizer and the gaps between the neutralizer particles. Therefore, using the washing water pipe 12 branched from the cold water supply pipe 2, it is possible to use the washing water pipe 12 at regular intervals, that is, irrespective of whether combustion is being performed or combustion is being stopped, or simply at regular intervals, or irregularly. Every time the accumulated combustion time elapses,
Cold water is automatically injected into the neutralizer 10 once or multiple times in a short time to remove deposits. The washing water pipe 12 is provided with an electromagnetic opening / closing valve 13, and the controller 15 opens and closes the valve 13 a predetermined number of times every time a predetermined period of time elapses. Further, another control circuit (duty control) may be added to the controller 15 to control the opening / closing cycle of the valve 13 and the time ratio of opening / closing. As described above, the time interval until the next cleaning and the length of the cleaning time change the setting of the time interval of the program control and the setting of the time ratio of the duty control according to the generation state of the deposit as described above. By doing so, it can be changed freely as shown in FIG.

The washing water pipe 12 may be branched from a hot water supply pipe 16 instead of the cold water supply pipe. Which one to use may be determined in consideration of the temperature dependence of the solubility of the solid neutralizing agent to be used and the like.

The upper end of the drain pipe 7 is open to the atmosphere via the receiving pan 6, while cold or hot water used for automatic cleaning is injected by the water pressure of a water supply source such as a water pipe. If the plate-like or granular solid neutralizer filled in the neutralizer 10 is clogged, the washing water may flow back to the drain pipe 7. A valve 14 is provided to prevent the washing water from overflowing from the tray 6.

[0016]

The neutralizing device according to the present invention can use a conventional solid neutralizer such as magnesium oxide or a magnesium alloy and a neutralizer, and can be easily reduced in size and size. Widely applicable to water heaters. The automatic cleaning means according to the present invention can arbitrarily set a cleaning interval by program control, and can also arbitrarily set the number of times the valve is opened and closed and the ratio of the opening and closing times during the cleaning, and the fuel gas Optimal cleaning can be performed even if the state of generation of corrosion products changes depending on the type and the material of the heat exchanger.

[0017]

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing an embodiment of a combustion device according to the present invention.

FIG. 2 is a diagram illustrating control of automatic cleaning according to the present invention.

FIG. 3 is an explanatory view of a conventional combustion device with a neutralizer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Burner 2 Water supply pipe 3 1st-stage heat exchanger 4 2nd-stage heat exchanger 5 Water drop 6 Receiving tray 7 Drain pipe 8 Fan 10 Neutralizer 11 Solid neutralizer 12 Washing water pipe 13 Electromagnetic on-off valve 14 Check valve 15 Electromagnetic Valve controller 16 Hot water supply pipe

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C02F 1/66 530 C02F 1/66 530Q F24H 9/00 F24H 9/00 BF Term (Reference) 3L034 BA26 3L036 AA14

Claims (3)

[Claims] 1. A combustion device provided with a latent heat recovery heat exchanger made of aluminum or an aluminum alloy, which collects a neutralizer filled with a solid neutralizer and exhaust gas drain generated in the latent heat recovery heat exchanger. And a means for intermittently supplying cold or hot water to the neutralizer intermittently. 2. The means for automatically supplying cold or hot water to the neutralizer intermittently connects a water supply pipe or a hot water supply pipe having an open / close valve to the neutralizer, and program-controls the opening and closing of the valve. The combustion device according to claim 1, further comprising a controller. 3. The water heater for burning a combustible gas, a liquefied petroleum gas or a city gas obtained by separating from natural gas or methane hydrate.
A combustion device as described.