JPH07127801A - Combustion type super-heater - Google Patents

Abstract

PURPOSE:To provide a combustion type super-heater having a superior durability and also having a superior thermal efficiency by a method wherein discharged gas in a discharged gas circulating passage is injected to a heat exchanging part and there is provided an agitating mechanism for agitating combustion gas to be fed to a heat exchanging part. CONSTITUTION:There are provide a combustion part 4, a heat exchanging part 5 having a heat transfer pipe 6 and for guiding combustion gas of high temperature generated at the combustion part 4, and a discharged gas circulating passage 7 for returning the combustion gas passed through the heat exchanging part 5 to the combustion part 4. In such a combustion type super-heater, the discharged gas in the discharged gas circulating passage 7 is injected to the heat exchanging part 5 and there is provided an agitating mechanism 8 for agitating the combustion gas fed to the heat exchanging part 5. Alternatively, the discharged gas of the discharged gas circulating passage 7 is injected to the heat transfer pipe 6 and there is provided a cleaning mechanism 9 for removing adhered substance in the heat transfer pipe 6. The combustion type super-heater super-heats steam of 60kgf/cm<2> and 310 deg.C generated at a waste heat boiler 2 installed at a municipal refuse incinerator 1 up to about 500 deg.C and then the steam is supplied to a power generating apparatus 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion part, a heat exchange part for arranging a heat transfer tube to guide high temperature combustion gas generated in the combustion part, and a combustion gas passed through the heat exchange part for the combustion part. The present invention relates to a combustion type superheater having an exhaust gas circulation path for returning to.

[0002]

2. Description of the Related Art As shown in FIG. 5, in a conventional combustion type superheater, a high temperature combustion gas generated in a combustion section 4 is mixed with exhaust gas returned through an exhaust gas circulation path 7 to reach a set temperature. By supplying the adjusted combustion gas to the heat exchange unit 5, the temperature of the combustion gas that has passed through the heat exchange unit 5, that is, the exhaust gas, is kept constant.

[0003]

However, when the amount of the combustion gas generated in the combustion section 4 is small, the flow of the combustion gas in the heat exchange section 5 is constantly deviated, and the heat transfer tube 6 is locally localized. As a result of excessive heating and corrosion, there is a risk of lack of durability. In addition, there is a drawback that thermal efficiency decreases as a result of scale and soot adhering to the surface of the heat transfer tube. An object of the present invention is to eliminate the above-mentioned conventional drawbacks.

[0004]

In order to achieve this object, the first characteristic configuration of the combustion type superheater according to the present invention is that the exhaust gas in the exhaust gas circulation passage is ejected to the heat exchange section to obtain the heat exchange section. The point is that a stirring mechanism is provided for stirring the combustion gas guided to. The second characteristic configuration is that a cleaning mechanism is provided for ejecting exhaust gas from the exhaust gas circulation path to the heat transfer tube to remove deposits on the heat transfer tube.

[0005]

According to the first characteristic configuration, even if a small amount of the combustion gas introduced to the heat exchange section causes a steady deviation, a part of the exhaust gas in the exhaust gas circulation path is generated by the stirring mechanism. Alternatively, the combustion gas is agitated by jetting all of the heat to the heat exchange section, and the heat exchange in the entire heat transfer tube is made uniform. According to the second characteristic configuration, even if scale or soot adheres to the surface of the heat transfer tube, a part or all of the exhaust gas of the exhaust gas circulation path is ejected to the surface of the heat transfer tube by the cleaning mechanism. The scale and soot can be blown away to improve the heat exchange efficiency in the heat transfer tube.

[0006]

According to the first characteristic configuration, even if the amount of combustion gas is small, it is possible to prevent local overheating of the heat transfer tube due to uneven gas flow in the heat exchange section, and it is excellent in durability. It is now possible to provide a combustion type superheater. According to the second characteristic configuration, it has become possible to provide a combustion type superheater having excellent thermal efficiency by removing scale and soot adhering to the surface of the heat transfer tube using exhaust gas for circulation. Further, by providing the damper mechanism, it is possible to provide a combustion type superheater having excellent durability and excellent thermal efficiency.

[0007]

EXAMPLES Examples will be described below. The combustion type superheater according to the present invention is, for example, as shown in FIG. 1, 60 kgf / cm ² , 31 in the waste heat boiler 2 provided in the municipal waste incinerator 1.
It is used to superheat the steam generated at 0 ° C. to about 500 ° C. and supply it to the power generation device 3. The combustion section 4 and the heat transfer tube 6 are used.
And a heat exchange section 5 for guiding the high temperature combustion gas generated in the combustion section 4, and an exhaust gas circulation path 7 for returning the combustion gas passing through the heat exchange section 5 to the combustion section 4. There is.

As shown in FIG. 2, the combustion section 4 is composed of a combustion burner 4a for combusting a fuel such as city gas or heavy oil and a combustion chamber 4b. The exhaust gas recirculation port is provided at the upstream side of the combustion chamber 4b. 4c is provided and the exhaust gas circulation path 7 is connected. The heat exchange section 5 is configured by disposing a plurality of heat transfer tubes 6 in a flue 5a for guiding the combustion gas in the combustion section 4 in a direction orthogonal to the flow of the combustion gas, and the waste heat boiler. Two
The steam generated in 1 is guided to the heat transfer tube 6 and superheated. The combustion gas that has passed through the heat exchange section 5 is collected by the electric dust collector 11, and then a part of the combustion gas is recirculated to the recirculation port 4c through the exhaust gas circulation path 7, and a part of the combustion gas is used as a combustion gas in the incinerator. 1 and is partially exhausted from a chimney (not shown).

That is, about 1800 ° C. generated in the combustion section 4
The high temperature combustion gas before and after is mixed with the exhaust gas returned through the exhaust gas circulation path 7, and the combustion gas after being adjusted to a set temperature of about 800 ° C. (varies depending on the amount of superheat) is transferred to the heat exchange section 5. The temperature of the combustion gas that has been supplied and passed through the heat exchange section 5, that is, the temperature of the exhaust gas is maintained at a constant temperature of approximately 400 ° C., and part of it is used efficiently as the secondary combustion gas for the incinerator 1. aim.

As shown in FIG. 3, in the exhaust gas circulation path 7, an exhaust gas supply path 8a is provided at a position on the near side to the recirculation port 4c, and a downstream side peripheral portion of the combustion chamber 4b via a damper 10a. Is connected to an annular blower pipe 8b arranged in the above, and thus constitutes an agitation mechanism 8 for ejecting exhaust gas to the heat exchange section 5 to agitate the combustion gas guided to the heat exchange section 5. The annular pipe 8b is formed with an ejection port (which may be a nozzle) 8c for ejecting the supplied exhaust gas so as to generate a swirling flow along the circumference thereof, so that the combustion gas from the burner 4a is discharged. Even when the amount of combustion gas is small, the swirling flow uniformly agitates the heat transfer section 5 to supply the heat transfer section 5 with a localized flow of the heat transfer tube 6 due to the deviation of the gas flow in the heat exchange section 5. Prevents overheating and high temperature corrosion to ensure durability.

As shown in FIG. 2, the exhaust gas circulation path 7 is provided with a plurality of blower pipes 9a extending to the flue 5a via a damper 10b, and the heat transfer pipes 6 are provided in each blower pipe 9a. An exhaust port (which may be a nozzle) 9b for ejecting the exhaust gas toward is formed so that the exhaust gas in the exhaust gas circulation path 7 is ejected to the heat transfer tube 6 to form the heat transfer tube 6
A cleaning mechanism 9 for removing the adhered substances (scale and soot) is constituted.

In a normal state, the dampers 10a and 10b are closed to circulate all the exhaust gas from the circulation path 7 to the combustion section 4. However, the combustion is performed to such an extent that the gas flow in the heat exchange section 5 becomes uneven. When the amount of combustion gas in the portion 4 is small, the opening degree of the damper 10a is adjusted according to the amount (for example, grasped from the supply amount of fuel gas or air to the burner 4a) to adjust the stirring mechanism 8 And the damper 10b is closed during the operation of the stirring mechanism 8 to prevent the cleaning mechanism 9 from operating. And, the damper 10b is regularly
Is opened to remove the deposits (scale and soot) on the heat transfer tube 6 and collect the dust by the electric dust collector 11 to improve the heat exchange efficiency in the heat transfer tube.

Another embodiment will be described below. The superheat condition in the combustion type superheater is not limited to the above numerical values,
It can be set appropriately according to the system used.

The case where the combustion type superheater is used for steam superheating of a refuse incinerator has been described, but the application is not particularly limited and is arbitrary.

In order to configure the stirring mechanism 8, the description has been given of the one in which the annular blower pipe 8b is arranged on the downstream side peripheral portion of the combustion chamber 4b. The shape of the outlet (which may be a nozzle) 8c is not particularly limited, and for example, as shown in FIG. 4, the blower pipe 8b may be formed in a "W" shape in cross section. However, it is necessary to avoid arrangements that obstruct the combustion gas flow as much as possible. Further, the combustion gas generated in the combustion section 4 is uniformly stirred even if the ejection port (or a nozzle) 8c is not formed so as to generate a swirl flow by the exhaust gas ejected from the ejection port 8c. If so, the ejection direction is not particularly limited.

The shape and arrangement of the blower pipe 9a constituting the cleaning mechanism 9 are not particularly limited and may be set appropriately. For efficient removal of deposits (scale and soot) on the heat transfer tube 6 by the cleaning mechanism 9, the dampers 10b for adjusting the ejection amounts from the blower pipes 9a are not simultaneously opened, but only one damper 10b is used. By performing the operation of opening all the dampers 10b in order, the deposits may be removed in a state where the ejection strength is further increased. The control mechanism for performing such an operation can be easily realized by using a known control circuit mechanism.

It should be noted that although reference numerals are given in the claims for convenience of comparison with the drawings, the present invention is not limited to the structures of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a refuse incinerator.

FIG. 2 is a vertical sectional view of a combustion type superheater.

FIG. 3 is a cross sectional view of a combustion type superheater.

FIG. 4 is a cross-sectional view of a combustion type superheater showing another embodiment.

FIG. 5 is a vertical sectional view of a combustion type superheater showing a conventional example.

[Explanation of symbols]

 4 Combustion part 5 Heat exchange part 6 Heat transfer tube 7 Exhaust gas circulation path 8 Stirring mechanism 9 Cleaning mechanism 10 Damper mechanism

Claims (2)

[Claims] 1. A heat exchange part (5) for arranging a combustion part (4) and a heat transfer tube (6) for introducing high temperature combustion gas generated in the combustion part (4), and the heat exchange part (5). A combustion-type superheater comprising: an exhaust gas circulation path (7) for returning the combustion gas that has passed through the combustion section (4) to the combustion section (4), wherein the exhaust gas from the exhaust gas circulation path (7) is converted into the heat exchange section (5).
A combustion type superheater provided with a stirring mechanism (8) for stirring the combustion gas that is jetted out to the heat exchange section (5) and stirred. 2. A heat exchange section (5) for arranging a combustion section (4) and a heat transfer tube (6) for guiding high temperature combustion gas generated in the combustion section (4), and the heat exchange section (5). A combustion type superheater comprising: an exhaust gas circulation path (7) for returning the combustion gas that has passed through the combustion section (4) to the heat transfer tube (6). A combustion type superheater provided with a cleaning mechanism (9) for ejecting to remove deposits on the heat transfer tube (6).