JP3025936B2 - Regenerative alternating burner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a regenerative alternating combustion burner used for a heating furnace or the like.

[0002]

2. Description of the Related Art In recent years, in order to enhance the thermal efficiency of a heating furnace, a technique has been developed in which a considerable amount of heat is recovered from combustion exhaust gas and the combustion air is preheated by this heat. Examples of such techniques include, for example, JP-A-59-93187, JP-A-62-94703, JP-A-62-908, and JP-A-62-908.
As disclosed in JP-A-3-159618 and the like, a pair of burners having ceramic balls and a honeycomb heat storage material are alternately burned, and the combustion exhaust gas is discharged through a non-burning burner-side heat storage material. A regenerative alternating combustion burner (hereinafter referred to as a regenerative burner) that preheats combustion air using heat of combustion exhaust gas stored in a heat storage body has been proposed and is being used. When this regenerative burner is used, the heat retained by the combustion exhaust gas is efficiently recovered and used for preheating the combustion air, so that further energy saving can be achieved as compared with the case of using a conventional burner.

[0003] In such a regenerative burner, most of the heat of the combustion exhaust gas is recovered by the heat accumulator and used for preheating the combustion air. In general, about 10 to 30% of the combustion exhaust gas is discharged as surplus exhaust gas without passing through the heat storage body because of the heat amount required for preheating the fuel. For example, in a continuous slab heating furnace equipped with a regenerative burner, surplus exhaust gas generated in each zone or unit furnace is collected and discharged from the furnace bottom side, or the characteristics of a heating furnace using a regenerative burner In order to ensure the independence of the temperature in each zone or unit furnace as one, the excess gas is discharged from a surplus gas discharge path separately provided for each zone or unit furnace. Further, in order to further improve the thermal efficiency, a heat recovery facility for surplus exhaust gas may be separately provided.

[0004]

In the conventional regenerative burner as described above, a discharge path or a heat recovery facility for discharging surplus exhaust gas must be provided.
This not only increases the equipment cost of the furnace, but also complicates emission control of the combustion exhaust gas which affects the pressure in the furnace.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and the amount of surplus exhaust gas is reduced by effectively using the combustion exhaust gas, or the temperature thereof is reduced, so that the equipment cost for the discharge path of the surplus exhaust gas is reduced. It is an object of the present invention to obtain a regenerative alternating combustion burner capable of reducing heat generation and improving heat recovery efficiency.

[0006]

SUMMARY OF THE INVENTION A regenerative alternating combustion burner according to the present invention is a regenerative alternating burner in which a pair of burners are alternately burned and the combustion exhaust gas is discharged through a regenerator provided in a regenerator on the non-burning burner side. In an alternating combustion burner, a combustion exhaust gas is provided in a combustion exhaust gas discharge path in or near the heat storage chamber .
It does not work when air is flowing, but works when flue gas is flowing.
The heat exchange type heat exchange means is provided.

In the above regenerative alternating combustion burner, fluid supply means for supplying the fluid heated by the heat exchange type heat exchange means to the burner is provided. Less than
Below, the above heat exchange type heat exchange means is simply referred to as heat exchange means or heat.
It is described as an exchanger.

[0008]

According to the present invention, the flue gas used for preheating the combustion air and the flue gas corresponding to the amount of heat given to the fluid flowing through the heat exchange means from the flue gas in the heat exchange means are discharged from the discharge path. Therefore, the amount of flue gas discharged from the discharge path can be increased, and in some cases, all the flue gas can be discharged from the discharge path. Thus, the temperature of the combustion exhaust gas passing through the heat storage chamber can be reduced, and the surplus exhaust gas discharge path can be simplified.

[0009] Further, by providing a fluid that has been heat-exchanged by the combustion exhaust gas into the burner,
When the fluid is water, the amount of surplus exhaust gas can be reduced and NOx in the combustion exhaust gas can be reduced by generating steam by the heat exchange means and blowing the steam into the burner. When the fluid is heavy oil, the heat exchange means can heat the fluid to a temperature suitable for spraying, so that the amount of heat held by the combustion exhaust gas can be effectively used.

[0010]

【Example】

Embodiment 1 FIG. 1 is a schematic diagram showing a configuration of an embodiment of the present invention. In the drawing, reference numerals 1a and 1b denote a pair of regenerative burners installed on a furnace wall 10 of a heating furnace.
a and 3b are nozzles, 4a and 4b are fuel supply pipes for supplying fuel to the nozzles 3a or 3b, and 5a and 5b supply combustion air to the nozzles 3a or 3b via the heat storage chamber 2a or 2b during combustion. When the fire is extinguished, the heat storage chamber 2a or 2b
A combustion air supply path (also referred to as a combustion exhaust gas discharge path) that discharges the combustion exhaust gas through the exhaust gas.

Reference numerals 6a and 6b denote heat exchangers provided in the heat storage chambers 2a and 2b. Reference numeral 7 denotes a fluid supply pipe for supplying a fluid to the heat exchanger 6a or 6b via a three-way valve 8.
The fluid heated at 6b is supplied to the nozzle 3a or 3b by the pipes 9a and 9b.

In the regenerative burners 1a and 1b as described above, in the state of FIG. 1, the regenerative burner 1b shows a combustion state, and the regenerative burner 1a shows a state of exhausting combustion exhaust gas.
Fuel is supplied from the fuel supply pipe 4b to the nozzle 3b, and combustion air preheated from the combustion air supply path 5b through the heat storage chamber 2b is supplied to the nozzle 3b. On the other hand, the fuel supply pipe 4a is closed, and the combustion exhaust gas in the furnace is discharged from the nozzle 3a through the heat storage chamber 2a to the combustion air supply path 5a, and during this time, the amount of heat held by the combustion exhaust gas is stored in the heat storage chamber 2a. Collected by the body (not shown).

The fluid flowing into the heat exchanger 6a from the fluid supply pipe 7 through the three-way valve 8 switched to the heat exchanger 6a is heated by the heat exchanger 6a by the combustion gas, and then connected to the pipe. It is supplied to the nozzle 3b during combustion by 9a. When the regenerative burner 1b burns, for example, for about 30 seconds, the fire extinguishes. At the same time, the regenerative burner 1a burns, and the combustion exhaust gas is discharged from the regenerative burner 1b. , The heat flows into the heat exchanger 6b, is heated, and is supplied to the nozzle 3a by the pipe 9b.

As described above, in this embodiment, the fluid flowing into the heat exchangers 6a and 6b provided in the heat storage chambers 2a and 2b is heated by heat exchange with the combustion exhaust gas to form the nozzle 3
a or 3b, the amount of exhaust gas discharged from the surplus gas discharge path is reduced, and the heat storage chamber 2
The temperature of the combustion exhaust gas passing through a and 2b can be reduced.

Next, embodiments of the present invention will be described in more detail. As described above, since the regenerative burner burns using the combustion air preheated to a high temperature, NOx is liable to be generated.
The steam addition method disclosed in Japanese Patent Application Laid-Open No. 2-155922 is effective. For this reason, in the present invention, if water is used as the fluid for performing heat exchange with the combustion exhaust gas by the heat exchangers 6a and 6b, the steam generated in the heat exchangers 6a and 6b can be used as the regenerative burners 1a and 1b. Low NO
Since it can be used as x-injection steam, NOx generated by using high-temperature combustion air can be reduced.

In this embodiment as described above, in the state of FIG. 2 , fuel is supplied from the fuel supply pipe 4a to the regenerative burner 1a, the switching valve 13a is opened, and the switching valve 13b is opened.
Is closed, and the air supply pipe 1 for combustion is
Combustion air is supplied from 2a to the heat storage chamber 2a to burn the regenerative burner 1a. On the other hand, the switching valve 16b is opened, the switching valve 16a is closed, and the combustion exhaust gas passing through the heat storage chamber 2b is sucked from the combustion exhaust gas discharge pipe 15b by the suction fan 17, and a part of the exhaust gas is dissipated from the chimney 19 and a part thereof is diffused. It is returned to the inlet side of the push-in fan 14 from the exhaust gas recirculation pipe 18.

By using the regenerative burner according to the present invention provided with means capable of exchanging heat with water, the heat exchanger 6
5 kg / cm ² steam at 0.5 kg / cm
When Nm ³ -fuel was generated and this generated steam was blown into the nozzle 3a or 3b for NOx reduction, the surplus exhaust gas amount was reduced to about 15%, and the NOx amount (11% O ₂ conversion) was reduced from 680 ppm to 370 ppm. Diminished. Note that the NOx amount could be further reduced to 110 ppm by performing exhaust gas recirculation as described below.

In a regenerative burner using heavy oil as fuel, heavy oil heated to about 80 to 90 ° C. by steam is conventionally used as fuel in order to give a viscosity suitable for spraying. However, the use of the regenerative burner according to the present invention makes it possible to easily heat heavy oil by heat exchange with flue gas, so that heavy oil whose viscosity has been adjusted can be used as fuel.

For example, in a combustion experiment using a regenerative burner of 200,000 kcal / h, when the entire amount of flue gas at 1100 ° C. is discharged through the regenerator, heavy oil at 20 ° C. is subjected to heat exchange with the flue gas. The temperature could be raised to 95 ° C., and a heavy oil having a viscosity suitable for spraying was obtained. In this case, not only the steam for adjusting the viscosity can be omitted, but also the temperature of the exhaust gas after passing through the regenerator is about 240 ° C. to 225 ° C.
C., the heat recovery efficiency can be improved.

Embodiment 2 FIG. 2 is a schematic view of a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the figure, reference numerals 12a and 12b denote switching valves 13
a, 13b via the heat storage chamber 2 of the heat storage type burners 1a, 1b
The combustion air supply pipes 14 connected to the heat storage chambers 2a and 2b pass through the combustion air supply pipes 12a and 12b.
This is a push-in fan for feeding air to the a and 2b.

Numerals 15a and 15b denote flue gas exhaust pipes connected to regenerative burners 1a and 1b via switching valves 16a and 16b, and 17 denotes flue gas from regenerative chambers 2a and 2b via flue gas exhaust pipes 15a and 15b. This is a suction fan for sucking air. 18 is an exhaust gas recirculation pipe connected between the inlet side of the pushing fan 14 and the outlet side of the suction fan 17,
Reference numeral 19 denotes a chimney provided on the outlet side of the suction fan 17.

In the present embodiment as described above, in the state shown in FIG. 1, fuel is supplied from the fuel supply pipe 4a to the regenerative burner 1a, and the switching valve 13a is opened and the switching valve 13b is opened.
Is closed, and the air supply pipe 1 for combustion is
Combustion air is supplied from 2a to the heat storage chamber 2a to burn the regenerative burner 1a. On the other hand, the switching valve 16b is opened, the switching valve 16a is closed, and the combustion exhaust gas passing through the heat storage chamber 2b is sucked from the combustion exhaust gas discharge pipe 15b by the suction fan 17, and a part of the exhaust gas is dissipated from the chimney 19 and a part thereof is diffused. The exhaust gas is returned to the inlet side of the pushing fan 14 by the exhaust gas recirculation pipe 18.

At this time, the three-way valve 8 is switched to the regenerative burner 1b and supplied from the fluid supply pipe 7 to the heat exchanger 6
The fluid flowing to b is heated by heat exchange with the combustion exhaust gas, and supplied to the burning regenerative burner 1a. In the present embodiment configured as described above, the thermal efficiency of the burner can be further improved, and at the same time, water is supplied to the heat exchangers 6a and 6b to generate steam, which is supplied to the burning burner. As described above, the NOx amount can be significantly reduced.

Embodiment 3 In the above embodiment, the heat exchangers 6a and 6b are connected to the heat storage chambers 2a and 2a.
2b, the heat exchangers 6a and 6b are connected to the flue gas discharge paths 5a and 5b as shown in FIG.
(Therefore, the heat storage chambers 2a and 2 of the combustion air supply path)
b, or may be provided downstream of the heat storage chambers 2a, 2b as shown in FIG. Even with such a configuration, the same effect as that of the first embodiment can be obtained.

Embodiment 4 Further, as shown in FIG.
5b is provided with branch pipes 11a and 11b connecting the upstream and downstream sides of the heat storage chambers 2a and 2b, and the branch pipes 11a and 11b are provided with heat exchangers 6a and 6b, respectively.
Heat exchange may be performed by the combustion exhaust gas diverted to 11b. The arrangement of the heat storage chamber and the heat exchanger and the type of the heat exchanger can be appropriately selected according to the use, the installation place, and the like.

As described in detail above, the regenerative alternating combustion burner according to the present invention does not operate when the combustion air is flowing into the flue gas exhaust passage in or near the regenerative chamber, and does not emit the exhaust gas.
A heat exchange means that operates when the gas flows is provided.
Since the fluid heated by the heat exchange means is supplied to the burner, the following effects can be obtained.
(1) Since the amount of flue gas discharged from the export route can be increased or the temperature of the flue gas can be reduced, the amount of surplus flue gas can be reduced and, in some cases, eliminated. Thus, equipment costs can be reduced.

(2) When the fluid flowing through the heat exchange means is water, the amount of NOx in the combustion exhaust gas can be reduced by generating steam by the heat exchange means and blowing it into a burner. . Furthermore, when the fluid is heavy oil, the heat exchange means can be heated to a temperature suitable for spraying, and the heat efficiency of the burner is improved by effectively utilizing the amount of heat held by the combustion exhaust gas. be able to.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a first embodiment of the present invention.

FIG. 2 is a schematic diagram of a second embodiment of the present invention.

FIG. 3 is a schematic diagram of a third embodiment of the present invention.

FIG. 4 is a schematic diagram of a third embodiment of the present invention.

FIG. 5 is a schematic diagram of a fourth embodiment of the present invention.

[Explanation of symbols]

 1a, 1b Thermal storage type alternating combustion burner 2a, 2b Thermal storage chamber 3a, 3b Nozzle 4a, 4b Fuel supply pipe 5a, 5b Air supply path for combustion 6a, 6b Heat exchanger 7 Fluid supply pipe 8 Three-way valve 9a, 9b Pipe 10 Furnace Wall 11 Branch pipe 18 Recirculation pipe

Continued on the front page (72) Inventor Shunichi Sugiyama 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Inside Nippon Kokan Co., Ltd. (72) Inventor Ryoichi Tanaka 2-53-1, Shirate, Tsurumi-ku, Yokohama-shi, Kanagawa Japan Furnace Within Industrial Co., Ltd. (72) Inventor: Mamoru Matsuo 2-1-153, Shirite, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Within Japan Furness Industry Co., Ltd. (72) Atsushi Sudo 2-1-1, Shirite, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture (56) References JP-A-5-117664 (JP, A) JP-A-57-61636 (JP, A) JP-A-6-241431 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F23L 15/00-15/04

Claims (2)

(57) [Claims] 1. A regenerative alternating combustion burner in which a pair of burners are alternately burned and the flue gas is discharged through a regenerator provided in a regenerator room on a non-burning burner side. In the route,
It does not operate when the combustion air is flowing, but when the combustion exhaust gas is flowing.
A regenerative alternating combustion burner, comprising a renewable heat exchange means that operates . 2. A regenerative alternating combustion burner according to claim 1, further comprising a fluid supply means for supplying a fluid heated by the heat exchange type heat exchange means to the burner.