TW202434836A - Regenerative burner - Google Patents

Abstract

[Topic] The topic of the present invention is to provide a regenerative burner, which forms a flame length that is between the short flame length of direct flame combustion and the long flame length of conventional diffuse combustion. [Solution] It is provided with: air supply and exhaust parts 11a, 11b, which supply combustion-supporting gas and discharge exhaust gas through heat storage bodies 12a, 12b arranged inside; first nozzles 21a, 21b, which are arranged inside the air supply and exhaust parts 11a, 11b and spray fuel; second nozzles 22a, 22b, which are separated from the air supply and exhaust parts 11a, 11b and spray the fuel along the flow direction of the combustion-supporting gas supplied from the air supply and exhaust parts 11a, 11b; and third nozzles 23a, 23b, which are arranged between the air supply and exhaust parts 11a, 11b and the second nozzles 22a, 22b, and spray the fuel to the combustion-supporting gas supplied from the air supply and exhaust parts 11a, 11b.

Description

Regenerative burner

[Invention Field]

The present invention relates to a regenerative burner. [Background Technology]

Conventionally, a pair of regenerative burners alternately supplies combustion gas and discharges exhaust gas, and high thermal efficiency is achieved by recovering the heat of the exhaust gas and utilizing it to preheat the combustion gas.

Patent document 1 discloses a burner that can change the flame length, etc. by changing the flow rate ratio of the fuel gas inflow and outflow. Patent documents 2 and 3 disclose a burner that sprays pre-mixed air and fuel from a central nozzle as a linear flame when the furnace is started or the furnace is below the ignition temperature, and when the ambient gas in the furnace reaches above the ignition temperature of the fuel, the fuel sprayed directly into the furnace is diffusely burned.

Patent document 4 discloses a regenerative burner device, which has a pair of auxiliary fuel pipes, an air supply and exhaust portion, and a main fuel pipe arranged in parallel horizontally, and adjusts the flame length and the temperature distribution in the furnace by staggering the combustion time of the auxiliary fuel pipe and the combustion time of the main fuel pipe.

[Patent Literature]

[Patent Document 1] Japanese Patent Publication No. 60-11018 [Patent Document 2] Japanese Patent Publication No. 2003-74834 [Patent Document 3] Japanese Patent Publication No. 2008-232475 [Patent Document 4] Japanese Patent Publication No. 6448679

[Invention Summary] [Problem to be solved by the invention]

In the past, in regenerative burners, direct fire combustion with a short flame length and diffuse combustion with a long flame length were used respectively, and the flame length was adjusted by adjusting the respective combustion amounts to adjust the temperature distribution in the furnace. However, in diffuse combustion, even if the combustion amount is reduced to shorten the flame length, in order to maintain stable diffuse combustion, for example, only 30% of the normal flame length of diffuse combustion can be shortened. In addition, in direct fire combustion, even if the combustion amount is maximized to maximize the flame length, it can only be extended to a length equivalent to 20% of the normal flame length of diffuse combustion. In order to lengthen the flame length in direct-fire combustion, the direct-fire combustion nozzle can be enlarged, but the high-temperature flame increases the emission of nitrogen oxides (NOx). Therefore, in conventional regenerative burners, there is a gap between the flame length of normal diffuse combustion and the flame length of direct-fire combustion.

Therefore, the subject of the present invention is to provide a regenerative burner, which forms a flame length between the short flame length of direct fire combustion and the long flame length of conventional diffuse combustion. [Means for solving the problem]

In order to achieve the above-mentioned problem, a heat storage burner of one aspect of the present invention is characterized by having: an air supply and exhaust section, which supplies combustion-supporting gas and discharges exhaust gas through a heat storage body arranged inside; a first nozzle, which is arranged inside the aforementioned air supply and exhaust section and sprays fuel; a second nozzle, which is arranged separately from the aforementioned air supply and exhaust section and sprays the aforementioned fuel along the flow direction of the aforementioned combustion-supporting gas supplied from the aforementioned air supply and exhaust section; and a third nozzle, which is arranged between the aforementioned air supply and exhaust section and the aforementioned second nozzle, and sprays the aforementioned fuel to the aforementioned combustion-supporting gas supplied from the aforementioned air supply and exhaust section.

According to the present invention, by using the new diffuse combustion of the third nozzle, a flame length intermediate between the short flame length of the direct fire combustion of the first nozzle and the long flame length of the normal diffuse combustion of the second nozzle can be formed, and the temperature distribution in the furnace can be adjusted without enlarging the first nozzle and suppressing the emission of nitrogen oxides (NOx).

[Form used to implement the invention]

Hereinafter, the embodiments of the regenerative burners 10a and 10b of the present invention will be described with reference to the drawings. However, for convenience, in FIG. 1 and the like, the left side is set as one side and the right side is set as the other side, sandwiching the center portion in the width direction of the furnace 1. In addition, in FIG. 1 and the like, the state of opening the valve is indicated by a blank, and the state of closing the valve is indicated by black. [First Embodiment]

The regenerative burners 10a and 10b of the first embodiment are described with reference to Figs. 1 to 3 and 5. Fig. 1 is a diagram schematically illustrating direct-fire combustion using the air supply and exhaust sections 11a and 11b in the regenerative burners 10a and 10b. (A) shows direct-fire combustion using the first nozzle 21a of one side, and (B) shows direct-fire combustion using the first nozzle 21b of the other side. Fig. 2 is a diagram schematically illustrating normal diffuse combustion in the regenerative burners 10a and 10b. (A) shows normal diffuse combustion using the second nozzle 22a of one side, and (B) shows normal diffuse combustion using the second nozzle 22b of the other side. Fig. 3 is a diagram schematically illustrating the regenerative burners 10a and 10b of the first embodiment. (A) shows the new diffused combustion using the third nozzle 23a of one of them, and (B) shows the new diffused combustion using the third nozzle 23b of the other. Fig. 5 is a diagram schematically illustrating the features of the regenerative burners 10a and 10b of the present invention. (A) shows the maximum flame length L1 during direct flame combustion using the first nozzle 21a, 21b, (B) shows the maximum flame length L2-1 during normal diffuse combustion using the second nozzle 22a, 22b, (C) shows the minimum flame length L2-2 during normal diffuse combustion using the second nozzle 22a, 22b, (D) shows the flame length L3 during new diffuse combustion using the third nozzle 23a, 23b.

As shown in FIG. 1 , for example, a pair of regenerative burners 10a and 10b are arranged opposite to each other in the furnace wall 2 of the furnace 1. One of the regenerative burners 10a has: one of the air supply and exhaust parts 11a having one of the air supply and exhaust ports 14a, one of the first nozzles 21a, one of the second nozzles 22a, and one of the third nozzles 23a. For example, one of the second nozzles 22a and 22a of the pair are separated and arranged with one of the air supply and exhaust parts 11a sandwiched therebetween, and one of the third nozzles 23a and 23a of the pair are arranged between one of the exhaust parts 11a and one of the second nozzles 22a. One of the air supply and exhaust ports 14a, one of the discharge ports of the second nozzle 22a, and one of the discharge ports of the third nozzle 23a are arranged on the wall surface 2 located on one of the sides, for example, in the same plane.

The other regenerative burner 10b also has: the other air supply and exhaust portion 11b having the other air supply and exhaust port 14b, the other first nozzle 21b, the other second nozzle 22b, and the other third nozzle 23b. For example, a pair of the other second nozzles 22b, 22b are separated and arranged with the other air supply and exhaust portion 11b sandwiched therebetween, and a pair of the other third nozzles 23b, 23b are arranged between the other exhaust portion 11b and the other second nozzle 22b. The other air supply and exhaust port 14b, the outlet of the other second nozzle 22b, and the outlet of the other third nozzle 23b are arranged, for example, on the wall surface 2 located on the other side in the same plane.

In one of the air supply and exhaust sections 11a, one of the heat storage bodies 12a is disposed therein, and one of the first nozzles 21a is disposed on the side closer to the furnace interior 3 than the one of the heat storage bodies 12a. In the other of the air supply and exhaust sections 11b, another of the heat storage bodies 12b is disposed therein, and another of the first nozzles 21b is disposed on the side closer to the furnace interior 3 than the other of the heat storage bodies 12b.

The first nozzle 21a, the second nozzle 22a, and the third nozzle 23a are connected to a fuel supply pipe 41 for supplying fuel. The fuel supply pipe 41 is provided with a first valve 31a corresponding to the first nozzle 21a, a second valve 32a corresponding to the second nozzle 22a, and a third valve 33a corresponding to the third nozzle 23a. The first valve 31a, the second valve 32a, and the third valve 33a adjust the amount of fuel supplied from the fuel supply pipe 41.

Similarly, the other first nozzle 21b, the other second nozzle 22b, and the other third nozzle 23b are each connected to a fuel supply pipe 41 for supplying fuel. The other first valve 31b corresponding to the other first nozzle 21b, the other second valve 32b corresponding to the other second nozzle 22b, and the other third valve 33b corresponding to the other third nozzle 23b are provided in the fuel supply pipe 41. The first valve 31b, the second valve 32b, and the third valve 33b respectively adjust the supply amount of the fuel supplied from the fuel supply pipe 41. As the fuel, for example, fuel gas such as natural gas (city gas), propane, butane, hydrogen, and ammonia is used.

The second nozzle 22a on one side and the second nozzle 22b on the other side are configured to spray fuel along the flow direction of the combustion-supporting gas sprayed from the air supply and exhaust portion 11a on one side and the air supply and exhaust portion 11b on the other side, respectively.

The third nozzle 23a on one side and the third nozzle 23b on the other side are respectively configured to spray fuel obliquely toward the flow of the combustion-supporting gas sprayed from the air supply and exhaust section 11a on one side and the air supply and exhaust section 11b on the other side. In this way, the sprayed fuel is diffused in the furnace 3 within a narrower range than the usual diffuse combustion and burns in a state of good mixing. Since the flame of the new diffuse combustion (illustrated as F3 in FIG. 5 (D)) is formed in a narrow range, the flame length of the new diffuse combustion (illustrated as L3 in FIG. 5 (D)) is shorter than the flame length of the usual diffuse combustion.

A combustion-supporting gas supply pipe 45 and an exhaust pipe 46 are connected to the air supply and exhaust section 11a on one side and the air supply and exhaust section 11b on the other side. The combustion-supporting gas supply pipe 45 is provided with a combustion-supporting gas valve 35a corresponding to the air supply and exhaust section 11a on one side and another combustion-supporting gas valve 35b corresponding to the air supply and exhaust section 11b on the other side. An air supply fan 51 is arranged on the upstream side of the combustion-supporting gas supply pipe 45, and the combustion-supporting gas is supplied to the air supply and exhaust sections 11a and 11b through the combustion-supporting gas supply pipe 45. As the combustion-supporting gas, for example, air can be used, or a single oxygen or a mixed gas containing oxygen can be used.

An exhaust fan 53 and a chimney 55 are provided on the downstream side of the exhaust pipe 46, and the exhaust gas flows through the exhaust pipe 46 and is discharged from the chimney 55. The exhaust pipe 46 is provided with an exhaust valve 36a corresponding to one of the air supply and exhaust parts 11a and another exhaust valve 36b corresponding to the other air supply and exhaust part 11b.

Next, the operation of the pair of regenerative burners 10a, 10b having the above-mentioned structure will be described.

Although not shown, when the furnace 1 starts operating, both the regenerative burners 10a and 10b are used simultaneously to burn the fuel sprayed from the first nozzles 21a and 21b and the combustion gas supplied from the combustion gas supply pipe 45 to increase the temperature of the furnace 3. The exhaust gas generated by the combustion is discharged through the exhaust port (not shown) provided in the furnace wall 2.

When the temperature in the furnace 3 reaches the ignition temperature of the fuel (e.g., 800°C) or higher, the operation of the regenerative burner 10a on one side and the operation of the regenerative burner 10b on the other side are switched to regenerative combustion. That is, in regenerative combustion, the following operations are performed alternately: the regenerative burner 10a on one side performs combustion operation and the regenerative burner 10b on the other side performs heat storage operation of heat storage exhaust gas, and the regenerative burner 10a on one side performs heat storage operation of heat storage exhaust gas and the regenerative burner 10b on the other side performs combustion operation. As described below, in the thermal storage combustion, diffusion combustion using the second nozzles 22a and 22b is usually performed (for simplicity, referred to as "normal diffusion combustion").

The normal diffusion combustion of the one regenerative burner 10a and the other regenerative burner 10b will be described with reference to FIG. 2 .

In FIG. 2(A), by opening the second valve 32a of one side, fuel is sprayed from the second nozzle 22a of one side, and the sprayed fuel is diffused in a wide range in the furnace 3. The fuel diffused in the furnace 3 meets the combustion gas supplied from the air supply and exhaust section 11a of one side by opening the combustion gas valve 35a of one side, whereby the regenerative burner 10a of one side performs normal diffusion combustion. Therefore, the second nozzle 22a of one side generates normal diffusion combustion at a position far away from the air supply and exhaust section 11a of one side.

In FIG. 2(B), the fuel is sprayed from the second nozzle 22b of the other side by opening the second valve 32b of the other side, and the sprayed fuel is diffused in a wide range in the furnace 3. The fuel diffused in the furnace 3 meets the combustion gas supplied from the other air supply and exhaust section 11b by opening the combustion gas valve 35b of the other side, whereby the other regenerative burner 10b performs normal diffusion combustion. Therefore, the second nozzle 22b of the other side generates normal diffusion combustion at a position far from the other air supply and exhaust section 11b.

Next, in normal diffuse combustion, since the temperature of the furnace interior 3 is higher than the ignition temperature of the fuel, the fuel sprayed from the second nozzles 22a and 22b spontaneously ignites when it meets the combustion-supporting gas supplied from the air supply and exhaust sections 11a and 11b.

Therefore, in the normal diffuse combustion using the second nozzles 22a, 22b, the fuel supplied to the furnace 3 is diffused and burned in a wide range in the furnace 3, and the second flame F2 of diffuse combustion is formed in various places in the furnace 3. The second flame F2 shown in FIG. 2 is also formed in the area that the first flame F1 of the direct fire combustion shown in FIG. 1 cannot reach, and heats the workpiece (not shown) in the furnace 3. Therefore, the heating performed by the normal diffuse combustion can be performed in a wide range in the furnace 3. In the normal diffuse combustion, since the flame temperature is reduced, the emission of nitrogen oxides (NOx) can be suppressed.

As shown in FIG. 2(A), while the regenerative burner 10a on one side performs normal diffusion combustion, the regenerative burner 10b on the other side performs heat storage operation. As shown in FIG. 2(B), while the regenerative burner 10a on one side performs heat storage operation, the regenerative burner 10b on the other side performs normal diffusion combustion.

The heat storage action of the regenerative burners 10a and 10b is described. In the heat storage action, heat is stored by the heat of the exhaust gas generated by the combustion of the regenerative burners 10a and 10b. For example, in FIG. 2(A), the exhaust gas generated by the normal diffusion combustion of the regenerative burner 10a on one side is sucked into the other side's supply and exhaust section 11b through the opening of the other side's exhaust valve 36b in the other side's regenerative burner 10b and the suction by the exhaust fan 53. In the process of the exhaust gas passing through the other side's supply and exhaust section 11b, the heat storage body 12b on the other side, which is arranged in the other side's supply and exhaust section 11b, absorbs the heat from the exhaust gas, and the heat storage body 12b on the other side is stored. When the heat stored in the other heat storage body 12b is then burned in the other heat storage burner 10b, the combustion-supporting gas is preheated when the combustion-supporting gas passes through the other heat storage body 12b.

Similarly, in FIG. 2(B), the exhaust gas generated by the normal diffusion combustion of the other regenerative burner 10b is sucked into the air supply and exhaust section 11a of one side through the exhaust valve 36a of one side in the regenerative burner 10a of one side opened and the exhaust fan 53. In the process of the exhaust gas passing through the air supply and exhaust section 11a of one side, the heat storage body 12a of one side disposed in the air supply and exhaust section 11a of one side absorbs the heat from the exhaust gas to store the heat of the heat storage body 12a of one side. The heat stored in the heat storage body 12a of one side is then preheated when the combustion-supporting gas passes through the heat storage body 12a of one side when the combustion-supporting gas is burned in the regenerative burner 10a of one side. Furthermore, the opening and closing operations of the above-mentioned various valves 31a, 31b, 32a, 32b, 33a, 33b, 35a, 35b, 36a, and 36b are controlled by a control unit (not shown).

In the case where a flame length shorter than the minimum flame length in the above-mentioned normal diffusion combustion (illustrated as L2-2 in FIG. 5(C)) is required in the regenerative combustion, direct-fire combustion is used. Referring to FIG. 1 , direct-fire combustion of one regenerative burner 10a and the other regenerative burner 10b is described.

As shown in FIG. 1(A), the first valve 31a of one side and the supporting gas valve 35a of one side are set to open, and the other valves 31b, 32a, 32b, 33a, 33b and the supporting gas valve 35b of the other side are set to close. In this way, the fuel sprayed from the first nozzle 21a of one side and the combustion-supporting gas supplied to the supply and exhaust part 11a of one side are pre-mixed. In the pre-mixed direct fire combustion, the first flame F1 of one side with high combustion efficiency and straightness is generated.

Similarly, as shown in FIG. 1(B), the first valve 31b and the supporting combustion gas valve 35b of the other side are opened, and the other valves 31a, 32a, 32b, 33a, 33b and the combustion-supporting gas valve 35a of one side are closed. In this way, the fuel ejected from the first nozzle 21b of the other side and the combustion-supporting gas supplied to the supply and exhaust part 11b of the other side are pre-mixed. In the pre-mixed direct fire combustion, the first flame F1 of the other side with high combustion efficiency and straightness is generated.

In the regenerative combustion, a new diffused combustion is performed when a flame length between the minimum flame length of the normal diffused combustion (illustrated as L2-2 in FIG. 5(C)) and the maximum flame length of the direct flame combustion (illustrated as L1 in FIG. 5(A)) is required. Referring to FIG. 3, the new diffused combustion of one regenerative burner 10a and the other regenerative burner 10b is described.

In FIG. 3(A), by opening the third valve 33a on one side and spraying fuel from the third nozzle 23a on one side, the sprayed fuel is diffused in the furnace 3 in a narrower range than the above-mentioned normal diffuse combustion. The diffused fuel meets the combustion-supporting gas supplied from the air supply and exhaust section 11a on one side by opening the combustion-supporting gas valve 35a on one side, thereby forming a new diffuse combustion flame (shown as F3 in FIG. 5(D)) in the narrow range of the regenerative burner 10a on one side. Therefore, the third nozzle 23a on one side generates new diffuse combustion having a flame length shorter than the flame length of the normal diffuse combustion (indicated by L3 in FIG. 5(D) ) at a position closer to the air supply and exhaust portion 11a on one side than the normal diffuse combustion.

In FIG. 3(B), the fuel is sprayed from the third nozzle 23b of the other side by opening the third valve 33b of the other side, and the sprayed fuel is diffused in the furnace 3 in a narrower range than the above-mentioned normal diffuse combustion. The diffused fuel meets the supporting combustion gas supplied from the other air supply and exhaust section 11b by opening the other combustion-supporting gas valve 35b of the other side, thereby forming a new diffuse combustion flame (indicated by F3 in FIG. 5(D)) of the other regenerative burner 10b in a narrow range. Therefore, the other third nozzle 23b generates new diffuse combustion having a flame length shorter than the flame length of the normal diffuse combustion (indicated by L3 in FIG. 5(D) ) at a position closer to the other air supply and exhaust portion 11b than the normal diffuse combustion.

Then, in the new diffuse combustion, since the temperature of the furnace 3 is higher than the ignition temperature of the fuel, the fuel sprayed from the third nozzles 23a and 23b spontaneously ignites when it meets the combustion-supporting gas supplied from the air supply and exhaust parts 11a and 11b.

Therefore, in the new diffuse combustion using the third nozzles 23a and 23b, the fuel supplied to the furnace 3 is diffused into the furnace 3 in a narrower range than in the case of the normal diffuse combustion, and burns in a state of good mixing, and the third flame F3 is formed by the new diffuse combustion at various places in the furnace 3. In the new diffuse combustion, as in the normal diffuse combustion, the flame temperature is lowered, so that the emission of nitrogen oxides (NOx) can be suppressed.

Similar to the usual diffuse combustion, as shown in FIG3(A), while the regenerative burner 10a on one side is performing new diffuse combustion, the regenerative burner 10b on the other side is performing heat storage based on the regenerative body 12b on the other side, and the heat stored in the regenerative body 12b on the other side is used to preheat the combustion gas when the combustion gas passes through the regenerative body 12b on the other side when the next regenerative burner 10b on the other side is burned. Furthermore, as shown in FIG. 3(B), while the other regenerative burner 10b is performing a new diffusion combustion, the regenerative burner 10a on one side performs a heat storage operation through the heat storage body 12a on one side, and stores heat in the heat storage body 12a on the other side. Then, when the regenerative burner 10a on one side is burning, the combustion-supporting gas is preheated when the combustion-supporting gas passes through the heat storage body 12a on the other side.

The difference in flame lengths of the regenerative burners 10a and 10b of the present invention will be described with reference to FIG. 5 .

As shown in FIG. 5(A), the first flame F1 during direct combustion using the first nozzles 21a and 21b forms a maximum flame length L1. As shown in FIG. 5(B), the second flame F2 during normal combustion using the second nozzles 22a and 22b forms a maximum flame length L2-1. As shown in FIG. 5(C), the second flame F2 during normal diffuse combustion using the second nozzles 22a and 22b forms a minimum flame length L2-2. As shown in FIG. 5(D), the third flame F3 during new diffuse combustion using the third nozzles 23a and 23b forms a flame length L3.

The first flame F1 produced by the direct fire combustion shown in FIG5(A) can also change the flame length by adjusting the combustion amount, but the variable range of the flame length is small, and the maximum is limited to the maximum flame length L1. The second flame F2 of the normal diffuse combustion can change the flame length more greatly than the first flame F1 shown in FIG5(A), and has a flame length range from the maximum flame length L2-1 shown in FIG5(B) to the minimum flame length L2-2 shown in FIG5(C). There is a blank flame length between the maximum flame length L1 of the direct fire combustion shown in FIG5(A) and the minimum flame length L2-2 of the normal diffuse combustion shown in FIG5(C).

In the new diffuse combustion, the ejected fuel diffuses in the furnace 3 in a narrower range than in the case of the normal diffuse combustion, and burns in a state of good mixing, thereby forming a flame length L3 shorter than the flame length of the normal diffuse combustion. The flame length L3 of the third flame F3 of the new diffuse combustion is constituted by the minimum flame length L2-2 including the second flame F2 of the normal diffuse combustion. Moreover, the flame length L3 is constituted by the maximum flame length L1 including the first flame F1 of the direct fire combustion. In other words, the adjustment range of the fuel flow rate of the third valve 33a, 33b is configured such that the flame length L3 of the third flame F3 of the third nozzle 23a, 23b includes the maximum flame length L1 of the first flame F1 of the first nozzle 21a, 21b and the minimum flame length L2-2 of the second flame F2 of the second nozzle 22a, 22b. Therefore, the third flame F3 generated by the new diffuse combustion is formed to have a flame length L3 intermediate between the maximum flame length L1 of the first flame F1 generated by the filling straight fire combustion and the minimum flame length L2-2 of the second flame F2 of the normal diffuse combustion. Thereby, the new diffuse combustion can fill the blank flame length with the flame length L3 between the maximum flame length L1 of the direct fire combustion and the minimum flame length L2-2 of the normal diffuse combustion.

Therefore, by using the new diffuse combustion of the third nozzles 23a and 23b, it is possible to form a flame length L3 that is between the short flame length of the direct flame combustion of the first nozzles 21a and 21b and the long flame length of the normal diffuse combustion of the second nozzles 22a and 22b, and it is possible to adjust the temperature distribution in the furnace without increasing the size of the first nozzles 21a and 21b and suppressing the emission of nitrogen oxides (NOx). [Second embodiment]

The regenerative burners 10a and 10b of the second embodiment are described with reference to Fig. 4. Fig. 4(A) is a cross-sectional view schematically illustrating a new diffuse combustion using the third nozzle 23a of one of the regenerative burners 10a and 10b of the second embodiment. Fig. 4(B) is a cross-sectional view schematically illustrating a new diffuse combustion using the third nozzle 23b of the other of the regenerative burners 10a and 10b of the second embodiment.

As shown in Fig. 4, the third nozzle 23a on one side and the third nozzle 23b on the other side are respectively located near the air supply and exhaust section 11a on one side and the air supply and exhaust section 11b on the other side. In addition, the third nozzle 23a on one side and the third nozzle 23b on the other side are respectively configured to spray fuel along the flow direction of the combustion-supporting gas sprayed from the air supply and exhaust section 11a on one side and the air supply and exhaust section 11b on the other side.

In FIG. 4(A), by opening the third valve 33a on one side, the fuel ejected from the third nozzle 23a on one side flows along the flow direction of the combustion-supporting gas, and the ejected fuel is diffused in the furnace 3 within a narrower range than the above-mentioned normal diffusion combustion. The diffused fuel meets the combustion-supporting gas supplied from the air supply and exhaust section 11a on one side by opening the combustion-supporting gas valve 35a on one side, whereby the regenerative burner 10a on one side performs new diffusion combustion. Therefore, the third nozzle 23a on one side generates new diffusion combustion at a position closer to the air supply and exhaust section 11a on one side than the normal diffusion combustion.

In FIG. 4(B), by opening the third valve 33b of the other side, the fuel ejected from the third nozzle 23b of the other side flows along the flow direction of the combustion-supporting gas, and the ejected fuel is diffused in the furnace 3 in a narrower range than the above-mentioned normal diffusion combustion. The diffused fuel meets the combustion-supporting gas supplied from the other air supply and exhaust section 11b by opening the combustion-supporting gas valve 35b of the other side, and the other regenerative burner 10b performs new diffusion combustion. Therefore, the third nozzle 23b of the other side generates new diffusion combustion at a position closer to the air supply and exhaust section 11b of one side than the normal diffusion combustion.

Then, similarly to the first embodiment described above, since the temperature of the furnace 3 is higher than the ignition temperature of the fuel, the fuel sprayed from the third nozzles 23a, 23b spontaneously ignites when it meets the combustion-supporting gas supplied from the air supply and exhaust sections 11a, 11b.

In the new diffuse combustion according to the second embodiment, the fuel supplied to the furnace 3 diffuses in the furnace 3 in a narrower range than the normal diffuse combustion and burns in a well-mixed state, and a new third flame F3 of the diffuse combustion is formed at various locations in the furnace 3. Therefore, by the new diffuse combustion using the third nozzles 23a and 23b, a flame length L3 between the short flame length of the straight fire combustion of the first nozzles 21a and 21b and the long flame length of the normal diffuse combustion of the second nozzles 22a and 22b can be formed, and the temperature distribution in the furnace can be adjusted in a state where the emission of nitrogen oxides (NOx) is suppressed without increasing the size of the first nozzles 21a and 21b. Next, compared with the first embodiment (shown in FIG. 3 ) in which the fuel is sprayed obliquely with respect to the flow direction of the combustion-supporting gas, the fuel is diffused further, thereby obtaining a flame length longer than the flame length shown in FIG. 3 . This can shift the adjustment range of the flame length to the long side, and can expand the application range.

Although specific embodiments and numerical values of the present invention have been described, the present invention is not limited to the above-described embodiments, and various modifications can be implemented within the scope of the present invention.

In the above-mentioned embodiment, it is illustrated that any one of the first valve 31a, 31b, the second valve 32a, 32b or the third valve 33a, 33b functioning as an on-off valve is set to open (the remaining part is set to closed), and any one of direct flame combustion, normal diffused combustion or new diffused combustion is performed. However, the first valve 31a, 31b, the second valve 32a, 32b and the third valve 33a, 33b may be respectively set as regulating valves capable of adjusting the opening of the valve body to change the ratio of the ejection flow rate from the first nozzle 21a, 21b, the ejection flow rate from the second nozzle 22a, 22b and the ejection flow rate from the third nozzle 23a, 23b. Thereby, the third flame F3 of the new diffuse combustion can form an intermediate appropriate flame length L3, and the aforementioned intermediate appropriate flame length L3 includes the maximum flame length L1 of the direct flame combustion and the minimum flame length L2-2 of the normal diffuse combustion. Thereby, a new intermediate flame length L3 of diffuse combustion using the third nozzles 23a and 23b can be formed, and the temperature distribution in the furnace can be adjusted while suppressing the emission of nitrogen oxides (NOx) without increasing the size of the first nozzles 21a and 21b.

In the above-mentioned new diffuse combustion, a new diffuse combustion using the third nozzle 23a or 23b is disclosed by opening only the third valve 33a or 33b. However, the fuel can also be ejected from the first nozzle 21a or 21b and the third nozzle 23a or 23b by opening both the first valve 31a or 31b and the third valve 33a or 33b. In this way, a newer combustion is generated in which the new diffuse combustion and the direct fire combustion are mixed, and a flame with a higher temperature than the above-mentioned new diffuse combustion can be formed. Furthermore, the ejection of the fuel from the first nozzle 21a, 21b and the third nozzle 23a, 23b can also be performed at the same time, or it can be performed at slightly different times.

In the above-mentioned embodiment, the regenerative burners 10a and 10b are provided in a form that is provided with the air supply and exhaust parts 11a and 11b, the first nozzles 21a and 21b, the second nozzles 22a and 22b, and the third nozzles 23a and 23b in advance. However, for the existing regenerative burners 10a and 10b provided with the air supply and exhaust parts 11a and 11b, the first nozzles 21a and 21b, and the second nozzles 22a and 22b, a modification project of adding a new diffusion combustion system including the third nozzles 23a and 23b can also be performed. Thereby, the above-mentioned new diffusion combustion can be easily added to the existing regenerative burners 10a and 10b.

The present invention and its embodiments are summarized as follows.

The heat storage burner 10a, 10b of one embodiment of the present invention is characterized by having: Air supply and exhaust parts 11a, 11b, which supply combustion-supporting gas and discharge exhaust gas by heat storage bodies 12a, 12b arranged inside; First nozzles 21a, 21b, which are arranged inside the air supply and exhaust parts 11a, 11b and spray fuel; Second nozzles 22a, 22b, which are separated from the air supply and exhaust parts 11a, 11b and spray the fuel along the flow direction of the combustion-supporting gas supplied from the air supply and exhaust parts 11a, 11b; and The third nozzles 23a and 23b are disposed between the air supply and exhaust sections 11a and 11b and the second nozzles 22a and 22b, and spray the fuel to the combustion-supporting gas supplied from the air supply and exhaust sections 11a and 11b.

According to the above-mentioned structure, by using the new diffuse combustion using the third nozzles 23a and 23b, it is possible to form a flame length L3 that is intermediate between the short flame length of the direct fire combustion using the first nozzles 21a and 21b and the long flame length of the normal diffuse combustion using the second nozzles 22a and 22b, thereby being able to adjust the temperature distribution in the furnace while suppressing the emission of nitrogen oxides (NOx) without increasing the size of the first nozzles 21a and 21b.

In addition, in the regenerative burners 10a and 10b of one embodiment, the third nozzles 23a and 23b are configured to spray the fuel obliquely toward the flow of the combustion-supporting gas.

According to the above-mentioned embodiment, since the ejected fuel diffuses in the furnace 3 within a range narrower than the usual diffuse combustion and burns in a well-mixed state, the flame of the new diffuse combustion is formed within a narrow range, so the flame length L3 of the new diffuse combustion is shorter than the flame length of the usual diffuse combustion.

Furthermore, in one embodiment of the regenerative burner 10a, 10b, a fuel supply pipe 41 for supplying the fuel to the first nozzle 21a, 21b, the second nozzle 22a, 22b and the third nozzle 23a, 23b is provided with a first valve 31a, 31b, a second valve 32a, 32b and a third valve 33a, 33b for adjusting the supply amount of the respective fuels, and a flame length L3 of the third flame F3 of the third nozzle 23a, 23b can be adjusted to include a maximum flame length L1 of the first flame F1 of the first nozzle 21a, 21b and a minimum flame length L2-2 of the second flame F2 of the second nozzle 22a, 22b.

According to the above-mentioned embodiment, the blank flame length can be filled with the flame length L3 between the maximum flame length L1 based on direct flame combustion and the minimum flame length L2-2 based on normal diffuse combustion.

In the regenerative burners 10a and 10b of one embodiment, the fuel is ejected from the first nozzles 21a and 21b and the third nozzles 23a and 23b.

According to the above embodiment, by ejecting fuel from both the first nozzle 21a or 21b and the third nozzle 23a or 23b, a further new combustion is formed in which new diffuse combustion and direct combustion are mixed, and a flame having a higher temperature than the above-mentioned new diffuse combustion can be formed.

On the other hand, a method for modifying a regenerative burner 10a, 10b is characterized in that: A third nozzle 23a, 23b is added to the regenerative burner 10a, 10b having an air supply and exhaust section 11a, 11b, a first nozzle 21a, 21b and a second nozzle 22a, 22b, The air supply and exhaust section 11a, 11b supplies combustion-supporting gas and discharges exhaust gas through the heat storage body 12a, 12b arranged inside, The first nozzle 21a, 21b is arranged inside the air supply and exhaust section 11a, 11b and sprays fuel; and The second nozzles 22a and 22b are separated from the air supply and exhaust sections 11a and 11b, and spray the fuel along the flow direction of the combustion-supporting gas supplied from the air supply and exhaust sections 11a and 11b. The third nozzles 23a and 23b are arranged between the air supply and exhaust sections 11a and 11b and the second nozzles 22a and 22b, and spray the fuel to the combustion-supporting gas supplied from the air supply and exhaust sections 11a and 11b.

According to the above method, the above-mentioned new diffusion combustion can be easily added to the existing regenerative burners 10a and 10b.

1: Furnace 2: Furnace wall 3: Furnace interior 10a, 10b: Regenerative burner 11a, 11b: Air supply and exhaust section 12a, 12b: Regenerative element 14a, 14b: Air supply and exhaust port 21a, 21b: No. 1 nozzle 22a, 22b: No. 2 nozzle 23a, 23b: No. 3 nozzle 31a, 31b: No. 1 valve 32a, 32b: No. 2 valve 33a, 33b: No. 3 valve 35a, 35b: Combustion gas valve 36a, 36b: Exhaust valve 41: Fuel supply pipe 45: Combustion gas supply pipe 46: Exhaust pipe 51: Air supply fan 53: Exhaust fan 55: Chimney F1: 1st flame F2: 2nd flame F3: 3rd flame L1: Maximum flame length of 1st flame L2-1: Maximum flame length of 2nd flame L2-2: Minimum flame length of 2nd flame L3: Flame length of 3rd flame

FIG. 1 is a diagram schematically illustrating direct-fire combustion using a supply and exhaust section in a regenerative burner. (A) shows direct-fire combustion using the first nozzle of one side, and (B) is a diagram showing direct-fire combustion using the first nozzle of the other side. FIG. 2 is a diagram schematically illustrating normal diffuse combustion in a regenerative burner. (A) shows normal diffuse combustion using the second nozzle of one side, and (B) shows normal diffuse combustion using the second nozzle of the other side. FIG. 3 is a diagram schematically illustrating a regenerative burner of the first embodiment. (A) shows new diffuse combustion using the third nozzle of one side, and (B) shows new diffuse combustion using the third nozzle of the other side. FIG. 4 is a diagram schematically illustrating a regenerative burner of the second embodiment. (A) shows a new diffuse combustion using the third nozzle of one side, and (B) shows a new diffuse combustion using the third nozzle of the other side. FIG. 5 is a diagram schematically illustrating the features of the regenerative burner of the present invention. (A) shows the maximum flame length when using the first nozzle for direct flame combustion, (B) shows the maximum flame length when using the second nozzle for normal diffuse combustion, (C) shows the minimum flame length when using the second nozzle for normal diffuse combustion, and (D) shows the flame length when using the third nozzle for new diffuse combustion.

2: Fireplace wall

11b: Air supply and exhaust section

14b: Air supply and exhaust port

21b: No. 1 nozzle

22b: No. 2 nozzle

23b: No. 3 nozzle

F1: No. 1 Flame

F2: Second Flame

F3: The 3rd flame

L1: Maximum flame length of the first flame

L2-1: Maximum flame length of the second flame

L2-2: Minimum flame length of the second flame

L3: Flame length of the third flame

Claims (5)

A regenerative burner is characterized by comprising: an air supply and exhaust section for supplying combustion-supporting gas and exhausting exhaust gas through a heat storage body arranged inside; a first nozzle arranged inside the air supply and exhaust section and spraying fuel; a second nozzle arranged separately from the air supply and exhaust section and spraying the fuel along the flow direction of the combustion-supporting gas supplied from the air supply and exhaust section; and a third nozzle arranged between the air supply and exhaust section and the second nozzle and spraying the fuel to the combustion-supporting gas supplied from the air supply and exhaust section. A regenerative burner as claimed in claim 1, wherein the third nozzle is configured to spray the fuel obliquely toward the flow of the combustion-supporting gas. A regenerative burner as claimed in claim 1, wherein a fuel supply pipe for supplying the aforementioned fuel to the aforementioned first nozzle, the aforementioned second nozzle and the aforementioned third nozzle is provided with a first valve, a second valve and a third valve for adjusting the supply amount of each of the aforementioned fuels, and the flame length of the third flame of the aforementioned third nozzle can be adjusted to include the maximum flame length of the first flame of the aforementioned first nozzle and the minimum flame length of the second flame of the aforementioned second nozzle. A regenerative burner as claimed in claim 1, wherein the fuel is sprayed from the first nozzle and the third nozzle. A method for modifying a regenerative burner, characterized in that: A third nozzle is added to a regenerative burner having an air supply and exhaust section, a first nozzle and a second nozzle, The air supply and exhaust section supplies combustion-supporting gas and discharges exhaust gas through a heat storage body arranged inside, The first nozzle is arranged inside the air supply and exhaust section and sprays fuel, The second nozzle is arranged separately from the air supply and exhaust section and sprays fuel along the flow direction of the combustion-supporting gas supplied from the air supply and exhaust section, The third nozzle is arranged between the air supply and exhaust section and the second nozzle and sprays the fuel to the combustion-supporting gas supplied from the air supply and exhaust section.