JP6017598B2 - Regenerative combustion equipment - Google Patents

Description

  The present invention relates to a self-exhaust exhaust gas recirculation (FGR) type regenerative combustion apparatus.

  In general, a regenerative combustion apparatus burns a pair of burners integrated with a heat storage body alternately at intervals of several tens of seconds, and when one burner is burning, the exhaust heats the heat storage body of the other burner. The heat energy of the exhaust gas is recovered, and when the burner burns next, high-efficiency combustion is obtained by passing the heated regenerator and preheating the combustion air. The energy of the combustion device is saved by recovering the heat of the exhaust to increase the combustion efficiency.

  In such a regenerative combustion apparatus, the exhaust gas recirculation system is configured to recirculate a part of the exhaust gas generated by combustion from the exhaust gas path to the fuel injection chamber through the recirculation path, thereby mixing NOx generated by combustion. This is intended to reduce this. At this time, a method of recirculating exhaust gas by suction (ejector effect) by fuel injection pressure is called a self exhaust gas recirculation (FGR) method. The self-exhaust gas recirculation type regenerative combustion apparatus is provided with a connecting pipe (FGR pipe) that connects the fuel injection chambers of each of the pair of burners, and each fuel injection chamber has a fuel injection nozzle and an exhaust flue. The mixing tube which serves also is connected oppositely (refer the following patent document 1).

JP-A-10-132211

  In the self-exhaust gas recirculation type regenerative combustion apparatus, the connecting pipe described above is heated by the heat of the exhaust gas passing therethrough, resulting in thermal distortion. The direction of the exhaust gas flowing through the connecting pipe is reversed by switching the combustion of the pair of burners, so that the thermal stress distribution of the connecting pipe is changed by the combustion switching of the burner, and stress is repeatedly generated at a specific location. Become. For this reason, there is a problem that the connecting pipe is liable to cause thermal fatigue.

  Conventionally, a stainless material having high heat resistance is used for the connecting pipe described above in consideration of thermal distortion. Further, in order to absorb the above-described repeated stress or to facilitate attachment to an existing burner, a corrugated expansion / contraction tube is provided in the middle portion of the connecting tube. However, the temperature of the recirculated exhaust gas may be 600 to 700 ° C., and the corrugated elastic tube portion is easily damaged in a short time due to the sensitization of the stainless material and the carbonization thinning.

  This invention makes it an example of a subject to cope with such a problem. That is, in a self-exhaust exhaust gas recirculation (FGR) type regenerative combustion apparatus, by providing a connecting pipe that is durable against thermal fatigue, and adopting a heat expansion / contraction absorption structure without a corrugated expansion / contraction pipe It is an object of the present invention to avoid short-time damage due to sensitization of stainless steel and carbonization thinning.

In order to achieve such an object, a regenerative combustion apparatus according to the present invention has the following configuration.
A regenerative combustion apparatus of a self-exhaust gas recirculation system comprising a pair of regenerative burners and a communication pipe communicating between the fuel injection chambers in each regenerative burner, wherein the communication pipe has one end side of the fuel A pair of slide short tubes connected to the ejection chamber; and a slide tube slidably coupled to an outer peripheral surface of the slide short tube via a ground seal structure, and a cylindrical shape along the inside of the slide tube A regenerative combustion apparatus comprising a heat insulating member.

  A regenerative combustion apparatus having such a feature is a slide in which a communication pipe communicating between fuel injection chambers is slidably connected to a pair of slide short pipes and an outer peripheral surface of the slide short pipe via a ground seal structure. It is composed of a tube, and the thermal expansion and contraction of the connecting tube is absorbed by a slide structure that hardly causes heat loss. As a result, it is possible to provide a connecting pipe having durability against thermal fatigue, and to obtain a regenerative combustion apparatus with high maintainability.

It is explanatory drawing which showed the principal part of the regenerative combustion apparatus which concerns on embodiment of this invention. It is explanatory drawing which showed the structural example of the regenerative combustion apparatus which concerns on embodiment of this invention. It is explanatory drawing which showed the other structural example of the regenerative combustion apparatus which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a main part of one embodiment of the present invention. A communication pipe (FGR pipe) 2 that communicates between the fuel injection chambers 1 of the pair of regenerative burners has a pair of slide short pipes 2A, one end of which is connected to the fuel injection chamber 1, and an outer peripheral surface of the slide short pipe 2A. The slide tube 2B is slidably connected via the ground seal structure 20, and a cylindrical heat insulating member 2C is disposed along the inside of the slide tube 2B. At this time, the outer diameter of the slide short tube 2A and the inner diameter of the heat insulating member 2C are made substantially equal.

  Here, the slide short tube 2A is made of a heat-resistant stainless steel material (such as SUS304), but the slide tube 2B is not heat resistant because it prevents the heat insulating member 2C from being heated to a high temperature. It can be composed of a steel material (SS material) or the like.

  The gland seal structure 20 includes a gland packing 21, holding members 22 and 23 that hold the gland packing 21 on the slide short pipe 2 </ b> A or the slide pipe 2 </ b> B, and a tightening member 24 that tightens the holding members 22 and 23. Airtightness can be increased by tightening the insert member 24.

  According to such a structure of the connecting pipe 2, the thermal expansion and contraction due to the heat of the exhaust gas is absorbed by the slide structure of the slide short pipe 2 </ b> A and the slide pipe 2 </ b> B, so that durability against thermal fatigue can be enhanced. At this time, since a corrugated expansion / contraction tube is not used, it is possible to avoid short-time damage due to sensitization of stainless steel and carbonization thinning, and increase the thickness of the slide short tube 2A and slide tube 2B. Therefore, it can be used for a long period of time while suppressing corrosion such as high temperature oxidation.

  The slide tube 2B can suppress the temperature rise to about 200 ° C. by disposing the heat insulating member 2C therein. As a result, a general-purpose steel material (carbon steel) can be used, and the cost of the connecting pipe 2 can be reduced.

  Furthermore, by making the inner diameter of the cylindrical heat insulating member 2C arranged in the slide tube 2B substantially equal to the outer diameter of the slide short tube 2A, an increase in internal loss of the exhaust gas flow flowing in the connecting tube 2 is suppressed. Can do.

  By adopting such a structure of the connecting pipe 2, it is a relatively inexpensive structure, and durability that can be used for a long time can be obtained. Further, since the gland seal structure 20 can restore the airtightness by tightening, the maintainability during long-term use can be ensured.

  FIG. 2 shows an example of the configuration of a regenerative combustion apparatus that can employ the configuration of the connecting pipe described above. In the regenerative combustion apparatus 100, a pair of regenerative burners 10 a and 10 b are installed at both ends of the radiant tube 9. The regenerative burners 10a and 10b have the same structure and are provided with a fuel injection chamber 1 communicated by the connecting pipe 2 described above. The fuel injection chamber 1 has a fuel injection nozzle 4, a mixing cylinder 5, and an exhaust. The cylindrical bodies that also serve as the flue 3 are connected to face each other.

  The regenerative burners 10a and 10b are provided with an air cylinder 6 having an air supply part (exhaust part) 7 so as to surround the fuel injection chamber 1, and a mixing cylinder 5 (exhaust flue 3) and an air cylinder. A cylindrical heat accumulator 11 is installed between 6. The cylindrical heat storage body 11 is configured by filling a large number of heat storage bodies 14 such as alumina balls between the inner cylinder 12 and the outer cylinder 13. The empty cylinder 6 is connected to the radiant tube 9 via the burner tile 15, and a pilot burner 8 is installed at the tip of the mixing cylinder 5 communicating with the radiant tube 9.

  In such a regenerative combustion apparatus 100, when one regenerative burner 10 a is combusted, air supplied from the air supply unit 7 into the air cylinder 6 is supplied from the outer periphery of the outer cylinder 13 of the cylindrical heat accumulator 11. It flows into the filling portion of the heat accumulator 14 in a centripetal manner, flows through the filling portion, then flows out into the inner cylinder 12, and is ejected from one end side of the inner cylinder 12 into the radiant tube 9 through the burner tile 15. Then, the fuel is ejected from the mixing cylinder 5 and mixed with an air-fuel mixture of combustion exhaust gas, and is used for combustion.

  On the other hand, in the other regenerative burner 10b, combustion is in a stopped state, naturally fuel is not injected, and the exhausted state. That is, the combustion exhaust gas of one regenerative burner 10a flows into the inner cylinder 12 from the burner tile 15 and then radially flows into the filling section, flows through the filling section, and flows into the air cylinder 6 from the outer periphery of the outer cylinder 13. And then flows out from the exhaust section 7 and is exhausted.

  At the next time when the combustion state is switched, the other regenerative burner 10b is in the combustion state, one regenerative burner 10a is in the combustion stopped state, and combustion air is supplied in the reverse path to the above description, and Combustion exhaust gas is exhausted. Thus, the air supply unit (exhaust unit) 7 operates as the exhaust unit (air supply unit) 7 at the next time point when the combustion state is switched.

  In the above operation, since the fuel injection chambers 1 of the respective regenerative burners 10a and 10b are connected by the communication pipe 2, the negative generated by the fuel injection in the regenerative burner 10a (or 10b) in the combustion state. Due to the pressure, in the regenerative burner 10b (or 10a) in the exhaust state, a part of the combustion exhaust gas is sucked from the radiant tube 9 into the fuel injection chamber 1 through the mixing cylinder 5 also serving as the exhaust flue 3 and communicated. It flows through the pipe 2 and flows into the fuel injection chamber 1 of the regenerative burner 10a (or 10b) in the combustion state, and is mixed with fuel as described above to perform exhaust gas recirculation combustion.

  In the embodiment shown in FIG. 2, an FGR heat storage body 16 such as a net tubular heat storage body is installed in the recirculation path of the combustion exhaust gas in the fuel injection chamber 1. For this reason, the combustion exhaust gas that has reached the fuel injection chamber 1 of the regenerative burner 10a (or 10b) on one side flows through the connecting pipe 2 in a state of releasing heat through the FGR heat accumulator 16, and the other side. When the regenerative burner 10b (or 10a) flows into the fuel injection chamber 1, the heat of the FGR heat accumulator 16 is taken away and the heat is recovered. Accordingly, the temperature of the combustion exhaust gas flowing through the connecting pipe 2 is lowered, so that heat is less radiated therefrom, the working environment is improved, and heat recovery is performed, so that the efficiency is also improved.

  FIG. 3 shows a configuration example of another regenerative combustion apparatus that can employ the configuration of the connecting pipe 2 described above. In this figure, the same components as those in FIG. 2 are denoted by the same reference numerals, and redundant description is omitted. In the regenerative combustion apparatus 100A of FIG. 4, regenerative burners 10a and 10b that are paired at appropriate positions of the furnace 17 are installed. Arrangement of the regenerative burners 10a and 10b forming a pair is appropriate such as arrangement opposite to each other as shown in the figure. The configuration and operation of the regenerative burners 10a and 10b are the same as those in FIG.

  In such a regenerative combustion apparatus 100, 100A, the connecting pipe 2 communicating between the pair of fuel injection chambers 1 is configured as shown in FIG. 1, whereby the durability of the connecting pipe 2 can be improved. The maintainability of the reactive combustion apparatuses 100 and 100A can be improved.

100, 100A: Regenerative combustion apparatus,
1: Fuel injection chamber, 2: Communication pipe (FGR pipe),
2A: Slide short tube, 2B: Slide tube, 2C: Thermal insulation member,
20: Gland seal structure, 21: Gland packing,
22, 23: holding member, 24: tightening member,
3: exhaust flue, 4: fuel injection nozzle, 5: mixing cylinder, 6: air cylinder,
7: Air supply part (exhaust part), 8: Pilot burner, 9: Radiant tube,
10a, 10b: Regenerative burner,
11: cylindrical heat storage body, 12: inner cylinder, 13: outer cylinder, 14: heat storage body,
15: Burner tile, 16: FGR regenerator, 17: Furnace

Claims (2)

A regenerative combustion apparatus of a self-exhaust gas recirculation system comprising a pair of regenerative burners and a communication pipe communicating between fuel injection chambers in each regenerative burner,
The connecting pipe is
A pair of slide short tubes whose one end side is connected to the fuel injection chamber, and a slide tube slidably connected to the outer peripheral surface of the slide short tube via a ground seal structure, are provided along the inside of the slide tube. A regenerative combustion apparatus in which a cylindrical heat insulating member is disposed.   The regenerative combustion apparatus according to claim 1, wherein an outer diameter of the slide short tube and an inner diameter of the heat insulating member are substantially equal.

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