JPH10169925A - Radiant tube burner system and operation thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heat and cool a radiant tube. SOLUTION: A radiant tube 3 is provided with a bypass tube 3b, a tube end 3a of the radiant tube 3 is fixed on a wall 7 of a heating furnace and a burner 5 housing a heat storage body 17 is mounted at the tube end 3a. The burner 5 is connected to a four-way valve 4 through a piping 10 and a gas cooler 9, an exhaust gas flow regulating means 6 and an exhaust gas section cutoff valve 8 are connected to the bypass tube 3b and then, to the four-way valve 4. A piping 19 for discharging an exhaust gas is provided between the exhaust gas flow regulating means 6 and the exhaust gas suction cutoff valve 8 and the radiant tube 3 can be functioned as cooling pipe mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiant tube burner system used as a heating source of an industrial heating furnace, a heat treatment furnace, and the like, and a method of operating the same. The present invention relates to a radiant tube burner system capable of adjusting an atmosphere to a desired temperature and an operation method thereof.

[0002]

2. Description of the Related Art FIG. 10 shows a conventional radiant tube burner, which is disclosed in Japanese Utility Model Laid-Open Publication No. 62-118925. At both ends of the radiant tube 81, burners 82 each having a combustion nozzle 83 and a heat storage body 84 are mounted. This burner is a burner that performs alternating combustion by alternately switching the burners 82 at both ends, and is called a regenerative radiant tube burner (regenerative radiant tube burner). Longer life, lower repair costs, etc. are achieved by making the temperature distribution of the tube uniform.

FIG. 11 shows a three-way radiant tube disclosed in Japanese Utility Model Laid-Open Publication No. 6-65705. The radiant tube 91 has a burner 92 mounted at one end and a heat storage body 93 at the other end. The combustion gas passing through the heat storage body 93 is alternately switched while burning the burner 92.

Further, Japanese Patent Application Laid-Open No. Hei 8-2474 by the present applicant has been disclosed.
The radiant tube disclosed in No. 21 has an arrangement in which the combustion air nozzle is eccentrically arranged in the radiant tube, and the velocity of the combustion jet is increased to 100 m / s or more.
A self-exhaust gas circulating flow is formed in the radiant tube, and the combustion exhaust gas is strongly burned while being involved in a large amount.
In such a combustion method, combustion can be realized without forming a local high-temperature region, and the generation of large amounts of nitrogen oxides, which is the biggest drawback of the regenerative radiant tube burner, can be suppressed. It is a radiant tube burner that can achieve low NOx combustion.

[0005]

In the conventional regenerative radiant tube burner system, the entire amount of the combustion exhaust gas burned in the radiant tube is usually discharged from the non-combustion burner through the regenerator, and the combustion air is discharged from the flue gas. High temperature preheated air is obtained using the heat extracted from the heat storage body as a preheat source to achieve high heat efficiency. However, the amount of heat that the high-temperature exhaust gas can radiate to the regenerator and the amount of heat that the combustion air can extract from the regenerator are not the same. That is, the amount of heat released by the exhaust gas is larger than the amount of heat that the combustion air can extract from the heat storage body, and when continuously burning, the temperature of the combustion exhaust gas released from the heat storage body tends to gradually increase. Therefore, in the case of infinite continuous combustion, only the amount of heat corresponding to the heat dissipated from the outer peripheral wall of the heat storage body is the amount of heat corresponding to the decrease in the exhaust gas temperature. That is, there was a problem that the water equivalent on the heat source side did not match the water equivalent on the heated side.

Here, a radiant tube burner system using city gas 13A as fuel will be considered as an example. The theoretical air amount of the city gas 13A is about 11 m ³ _N / m ³ _N , and the theoretical wet exhaust gas amount is about 12 m ³ _N / m ³ _N. In the case of a radiant tube burning at an air ratio of 1.2, the combustion exhaust gas generated per m ³ _{N of} fuel is about 14 m ³ _N. Assuming that the specific heat of the combustion exhaust gas is equal to the specific heat of the air and the water equivalent is considered, the exhaust gas is about 1.3 times the air. In an ideal regenerative heat exchanger, at the start of operation, the exhaust gas outlet temperature is exhausted at room temperature, the combustion air flows in through the regenerative heat exchanger, and the combustion air air temperature becomes the inlet exhaust gas temperature. If so, a difference between the amount of heat released from the exhaust gas to the heat storage unit and the amount of heat removed from the heat storage unit by the combustion air is generated by the difference between the flow rates.

However, since the specific heat of the air is smaller than the specific heat of the exhaust gas, the difference between the calorific value of the exhaust gas and the calorific value of the air further occurs. If continuous operation is performed in this state, the exhaust gas temperature at the exhaust gas outlet of the heat storage body gradually increases. Actually, since the amount of heat dissipated from the wall surrounding the heat storage body exists, the degree of increase in the exhaust gas temperature at the exhaust gas outlet of the heat storage body changes depending on the arrangement of the heat storage body. Further, if a state occurs in which the difference between the amount of heat dissipated by the regenerative heat exchanger, the amount of heat released from the exhaust gas, and the amount of heat released from the air coincides, the temperature state of each part is maintained.

Coke oven gas (C
OG), the theoretical amount of COG air is about 4.
7Nm ³ / Nm ³ , theoretical wet exhaust gas amount is about 5.4Nm ³
/ Nm ³ . In the case of a radiant tube burning at an air ratio of 1.2, the combustion exhaust gas generated per 1 Nm ^{3 of} fuel is about 6.4 Nm ³ . Assuming that the specific heat of the combustion exhaust gas is equal to that of the air and the water equivalent is considered, the exhaust gas is about 1.35 times that of the air and has the same problem as the city gas 13A.

On the other hand, it is known that a regenerative radiant tube burner system is a highly efficient exhaust heat recovery system. As a method of using a radiant tube, there is a radiant tube burner system in which a burner is arranged and used as a heating source, and in addition, a fuel is shut off and only combustion air flows through the radiant tube to be used as a cooling pipe. This heating / cooling type radiant tube is a highly efficient waste heat recovery system when the regenerative radiant tube burner system is used as it is, so the heat recovery efficiency during heating is high, but the radiant tube is used as a cooling pipe. When used, preheated air flows into the radiant tube, and the cooling capacity is reduced. That is, there is a drawback that the cooling capacity is lower than that of a conventional radiant tube into which room-temperature air can be continuously introduced.

When the regenerative radiant tube burner system is used as a heating and cooling type, there is a method of increasing the switching time of the burners mounted at both ends of the radiant tube, that is, the air passage switching time to lower the air temperature. Conceivable. However, the exhaust equipment after the heat storage body may be made of a material corresponding to low-temperature exhaust gas, but when using a radiant tube as a cooling pipe, a high-temperature fluid will be discharged, and a material corresponding to a high-temperature fluid will be used. Need arises. Therefore, there is a disadvantage that the material cost rises and the equipment cost rises.

Further, when the furnace temperature is raised from room temperature to the set temperature, the exhaust heat recovery system is highly efficient.
At a time when the furnace temperature is low, that is, immediately after startup and until the furnace temperature rises, low-temperature exhaust gas flows into the heat storage body rapidly. At this time, the temperature on the outlet side where the combustion exhaust gas is discharged from the heat storage body (hereinafter, referred to as the heat storage body discharge side exhaust gas temperature) is equal to or lower than the exhaust gas dew point temperature. as a result,
If the fuel used contains sulfur, dew condensation occurs and low-temperature corrosion occurs. When the furnace is in operation and the temperature of the exhaust gas on the exit side of the heat storage unit rises and becomes higher than the acid dew point temperature, there is no problem of low-temperature corrosion. However, when used for a long period of time, there is a problem that time for exposure to a low-temperature corrosion state accumulates, and equipment destruction due to low-temperature corrosion eventually occurs.

The present invention has been made to solve the above problems, and has as its object to provide a radiant tube burner in which a heating furnace can be easily heated and cooled, and a method of operating the radiant tube burner.

Further, the present invention provides a radiant tube burner system capable of suppressing a rise in the temperature of combustion exhaust gas discharged from a heat storage body even in continuous combustion and having a function as a cooling pipe, and a method of operating the same. It is the purpose.

Further, the present invention suppresses a rise in the temperature of the combustion exhaust gas discharged from the regenerator even in a continuous combustion state, enhances the cooling performance of the radiant tube burner at the time of the cooling pipe function, and reduces the low furnace temperature operation. It is an object of the present invention to provide a radiant tube burner system with high thermal efficiency, which can prevent equipment destruction due to low-temperature corrosion at the time, and a method of operating the radiant tube burner system.

Further, according to the present invention, it is possible to stabilize the temperature of the combustion exhaust gas of the regenerator even in 100% load continuous combustion, and to enhance the cooling performance of the regenerative radiant tube burner system at the time of the cooling bipe function. It is an object of the present invention to provide a radiant tube burner system capable of preventing equipment destruction due to low-temperature corrosion during low furnace temperature operation and achieving high thermal efficiency, and an operation method thereof.

[0016]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a radiant tube burner system according to the first aspect of the present invention has a radiant tube burner system having three or more ends. A radiant tube having a radiant tube, and a burner having a waste heat recovery means disposed at at least two places of the end portion. Fluid flowing into the radiant tube from the remaining end portion where the burner is not disposed is provided with combustion exhaust gas and combustion air. The exhaust gas is discharged to an exhaust gas discharge pipe without passing through a switching valve that switches a flow path between the exhaust gas and the exhaust gas. This invention controls the temperature in the radiant tube by discharging the combustion exhaust gas from the exhaust gas discharge pipe without passing through the waste heat recovery means.

In a radiant tube burner system according to a second aspect of the present invention, in the radiant tube burner system according to the first aspect, the waste heat recovery means is a heat storage material having air permeability or a heat storage material and a perforated plate. It is characterized in that the flow resistance of the waste heat recovery means of the combustion exhaust gas is small, and an abnormal pressure in the radiant tube can be avoided.

According to a third aspect of the present invention, there is provided a radiant tube burner system according to the first or second aspect, wherein a pipe is provided from an end of the radiant tube where no burner is disposed to the exhaust gas discharge pipe. A cooling means for cooling the flue gas is provided in the path. According to the present invention, since the combustion exhaust gas is discharged by cooling the cooling means, the heat-resistant temperature of the exhaust gas discharge pipe can be reduced.

The radiant tube burner system according to a fourth aspect of the present invention is the radiant tube burner system according to the first, second, or third aspect, wherein the inside length of the radiant tube, in which no burner is disposed, is one of the furnace width. /
It has a length of 2 or more. The present invention
The temperature in the furnace in the furnace width direction can be made a uniform temperature distribution.

The radiant tube burner system according to a fifth aspect of the present invention is the radiant tube burner system according to the first, second, third, or fourth aspect, wherein the exhaust gas discharge line extends from an end of the radiant tube where no burner is disposed. And a flow rate adjusting means for adjusting the amount of fluid discharged from the exhaust gas discharge pipe. ADVANTAGE OF THE INVENTION This invention can control so that it may not exceed the heat-resistant temperature of the piping for exhaust gas discharge by adjusting the flow volume of exhausted flue gas.

The radiant tube burner system according to the invention of claim 6 is the radiant tube burner system according to claim 1, 2, 3, 4 or 5, wherein the fluid passing through the waste heat recovery means and the burner are used. Flow rate adjusting means for adjusting the fluid discharged from the end of the radiant tube which is not disposed, and merging and discharging the respective fluids is provided between the exhaust gas discharge pipe line. . According to the present invention, by the flow rate adjusting means,
The flow rate of the combustion exhaust gas that has passed through the heat storage element and the combustion exhaust gas that has not passed through the heat storage element is adjusted and discharged from the exhaust gas discharge pipe.

Further, the radiant tube burner system according to the invention of claim 7 is characterized in that:
In the radiant tube burner system described in
On a small refractory wall of a refractory wall structure equivalent to the furnace wall corresponding to the opening provided in the furnace wall of the heating furnace, the radiant tube is mounted, and the small refractory wall on which the radiant tube is mounted is It is a structure that can be attached and detached from the opening. The present invention enhances the workability of mounting the radiant tube during construction and the workability during maintenance and inspection.

A radiant tube burner system according to the invention of claim 8 includes a radiant tube having three or more ends; a burner disposed at at least two of the ends and having waste heat recovery means; A switching valve for alternately switching the supply of combustion air to the burner and the discharge of combustion exhaust gas from the burner to the exhaust gas discharge pipe; reducing the temperature of the fluid discharged from the end of the radiant tube without a burner Cooling means for adjusting the flow rate of the fluid cooled by the cooling means; suction for discharging the fluid in the radiant tube from the exhaust gas discharge pipe from the end of the radiant tube where no burner is provided. Exhaust gas shut-off means; alternately burning the burner; the suction exhaust gas shut-off means; And a control device and by operating the suction gas shutoff means for controlling the radiant tube temperature: characterized by including the. According to the present invention, the temperature inside the radiant tube can be controlled by discharging the combustion exhaust gas in the radiant tube while controlling the flow rate and the temperature.

A radiant tube burner system according to a ninth aspect of the present invention is the radiant tube burner system according to any one of the first to eighth aspects, wherein a cooling medium is supplied into the radiant tube and the radiant tube inside the radiant tube. And a temperature control means for adjusting the temperature of the light source. The temperature inside the radiant tube can be reduced by the cooling medium.

A radiant tube burner system according to a ninth aspect of the present invention is the radiant tube burner system according to the ninth aspect, wherein the temperature control means includes:
A cooling medium is injected into the radiant tube from all or some of the burners without supplying any fuel to each of the burners, and the whole or a part of the injected cooling medium is discharged from the end where no burner is disposed. It is a means for discharging through the exhaust gas discharge pipe. According to the present invention, since the temperature in the radiant tube can be rapidly reduced, an abnormal temperature can be avoided.

[0026] In a radiant tube burner system according to a ninth aspect of the present invention, in the radiant tube burner system according to the ninth aspect, the temperature control means includes:
It is a means for changing the number of burners into which the cooling medium is charged and / or the amount of the cooling medium charged. This invention, according to the temperature in the radiant tube,
The abnormal temperature can be avoided by controlling the degree of cooling.

A radiant tube burner system according to a twelfth aspect of the present invention is the radiant tube burner system according to the ninth aspect, wherein the temperature control means comprises:
It is a means for controlling the supply amount of the cooling medium based on the deviation between the current furnace temperature and the target furnace temperature to be reduced, and controls the degree of cooling to avoid abnormal temperatures.

A radiant tube burner system according to a thirteenth aspect of the present invention is the radiant tube burner system according to the ninth aspect, wherein the temperature control means comprises:
It is a means for controlling the supply amount of the system leg medium based on the furnace temperature reduction amount per unit time, and controls the degree of cooling to avoid abnormal temperatures.

A radiant tube burner system according to a fourteenth aspect of the present invention is the radiant tube burner system according to the eleventh aspect, wherein the temperature control means does not supply fuel to each burner at all but only some of the burners. The cooling medium is supplied, and the air inlet of the combustion air is switched by each burner alternately, and discharged from the end of the radiant tube in which no burner is disposed in the whole or a part of the supplied cooling medium, and the furnace temperature is reduced. It is a means for lowering the temperature and controls the temperature inside the radiant tube burner.

A radiant tube burner system according to a fifteenth aspect of the present invention is the radiant tube burner system according to the eleventh aspect, wherein the temperature control means sets the radiant tube burner as long as the furnace internal temperature does not reach a set temperature. It is a means for supplying a cooling medium into the burner, and discharging the entire amount of combustion exhaust gas in the radiant tube from a tube end of the radiant tube where no burner is provided, and is controlled according to a temperature in the radiant tube.

The radiant tube burner system according to the invention of claim 16 is the radiant tube burner system according to any one of claims 9 to 15, wherein the cooling medium is not flammable such as air, nitrogen, and combustion gas. It is characterized by being a fluid or a mixed fluid thereof, and is selected according to the temperature in the radiant tube to avoid an abnormal temperature.

A radiant tube burner system according to a seventeenth aspect of the present invention is the radiant tube burner system according to any one of the first to sixteenth aspects, further comprising a drain discharge device for discharging drain from inside the radiant tube. By providing a device for discharging drain, the device adheres to the thin tube of the heat storage body, thereby preventing a decrease in the flow rate of combustion air and a decrease in the temperature in the radiant tube due to the drain.

The radiant tube burner system according to the invention of claim 18 is the radiant tube burner system according to any one of claims 1 to 17, wherein the temperature of an arbitrary place of a heating furnace in which the radiant tube burner system is disposed. When the temperature does not reach the predetermined temperature, the burner disposed in the radiant tube has a control means for setting the burner to a combustion state by the number of ignitions greater than the number of ignitions in the normal operation. The present invention is for rapidly increasing the temperature in a furnace in which a radiant tube burner is installed, and can provide a variety of heat treatments for an object to be heated in the furnace.

A radiant tube burner system according to a nineteenth aspect of the present invention is the radiant tube burner system according to any one of the first to seventeenth aspects, wherein a temperature of an arbitrary place in a heating furnace in which the radiant tube burner system is disposed is provided. A control means for igniting all the burners arranged in the radiant tube while the temperature does not reach a predetermined temperature. The present invention is for rapidly increasing the temperature in a furnace in which a radiant tube burner is installed, and can provide a variety of heat treatments for an object to be heated in the furnace.

A radiant tube burner system according to a twentieth aspect of the present invention is the radiant tube burner system according to any one of the first to seventeenth aspects, wherein the temperature of the heating furnace in which the radiant tube burner system is arranged is determined. A plurality of predetermined temperatures, and control means for changing the number of ignitions of burners arranged in the radiant tube for each of the predetermined temperatures. According to the present invention, a temperature distribution can be given to the furnace temperature by selecting a combustion location of the radiant tube burner.

The radiant tube burner system according to the invention of claim 21 is the radiant tube burner system according to any one of claims 1 to 17, wherein the temperature in the furnace is increased by the temperature in the furnace in each zone of the heating furnace.・
It is characterized by having control means for adjusting the decrease. According to the present invention, a temperature distribution can be given to the furnace temperature by selecting a combustion location of the radiant tube burner.

A radiant tube burner system according to a twenty-second aspect of the present invention is the radiant tube burner system according to any one of the first to seventeenth aspects, wherein the temperature of the fluid discharged from the end of the radiant tube is increased. And a control means for adjusting the furnace temperature by measuring the temperature inside the furnace from the temperature of the fluid discharged from the radiant tube burner.

A radiant tube burner system according to a twenty-third aspect of the present invention is the radiant tube burner system according to any one of the first to seventeenth aspects, wherein the control means for adjusting the furnace temperature by the surface temperature of the radiant tube. The temperature inside the furnace can be measured by attaching it to a radiant tube near the furnace wall outside the furnace.

A radiant tube burner system according to a twenty-fourth aspect of the present invention is the radiant tube burner system according to any one of the first to seventeenth aspects, wherein the temperature inside the furnace is determined by the temperature of the fluid discharged from the waste heat recovery means. It is characterized by having a control means for adjusting the temperature of the furnace, so that the temperature inside the furnace can be measured outside the furnace.

A radiant tube burner system according to a twenty-fifth aspect of the present invention is the radiant tube burner system according to any one of the first to twenty-fourth aspects, wherein the diameter of the tube end of the radiant tube in which no burner is disposed is a burner. The diameter of the radiant tube is smaller than the diameter of the radiant tube, and the combustion control can be performed without adversely affecting the flow of the combustion exhaust gas in the radiant tube.

According to a twenty-sixth aspect of the present invention, in the radiant tube burner system operating method, at least two or more of three or more ends of the radiant tube are provided.
Arranging a burner having waste heat recovery means to perform alternating combustion; and, when lowering the temperature in the radiant tube, combusting the combustion exhaust gas discharged from the pipe end of the radiant tube having the burner disposed therein with the combustion exhaust gas. Discharging through an exhaust gas discharge pipe without passing through a switching valve for switching the working air, thereby reducing the temperature in the radiant tube. According to the present invention, the temperature inside the radiant tube is controlled by discharging the combustion exhaust gas without passing through the waste heat recovery means.

A method of operating a radiant tube burner system according to a twenty-seventh aspect of the present invention is the method of operating a radiant tube burner system, wherein at least two or more of three or more ends of the radiant tube are provided.
A step of arranging a burner having waste heat recovery means to perform alternating combustion; and, when lowering the temperature in the radiant tube, flowing a cooling medium into the radiant tube to form a pipe end of the radiant tube in which a burner is arranged. Cooling the flue gas discharged from the exhaust gas and discharging it from the flue gas discharge pipe without passing through a switching valve for switching between the flue gas and the combustion air, thereby reducing the temperature in the radiant tube. It is characterized by. According to the present invention, the cooling medium flows into the radiant tube to control the temperature inside the radiant tube.

The operating method of the radiant tube burner system according to the invention of claim 28 is the method of operating a radiant tube burner system, wherein at least two or more of three or more ends of the radiant tube are provided.
A step of arranging a burner having a waste heat recovery means to perform alternating combustion; and, when lowering the temperature in the radiant tube, supplying a cooling medium from all or some burners without supplying any fuel to each burner. And discharging the whole or a part of the input cooling medium from the end where the burner is not disposed. According to the present invention, the temperature is controlled by controlling the amount of the supplied cooling medium in the radiant tube.

The method for operating a radiant tube burner system according to the invention of claim 29 is the method for operating a radiant tube burner system, wherein at least two or more of three or more ends of the radiant tube are provided.
Arranging a burner having waste heat recovery means to perform alternating combustion; and when lowering the temperature in the radiant tube, a deviation between a current furnace temperature and a target furnace temperature,
Controlling the temperature in the furnace.

The method for operating the radiant tube burner system according to the invention of claim 30 is described in claims 26 to 2.
9. The operating method of the radiant tube burner system according to any one of the items 9, further comprising a step of controlling the temperature in the radiant tube by a change amount of the temperature in the furnace per unit time, whereby the temperature can be controlled at high speed. .

The operation method of the radiant tube burner system according to the invention of claim 31 is described in claims 26 to 2.
In the operating method of the radiant tube burner system according to any one of 9, the flow rate of the fluid discharged from the end where no burner is disposed and the flow rate of the fluid that has passed through the waste heat recovery means and the four-way valve are adjusted. It is characterized by having a step of merging and discharging the exhaust gas from the exhaust gas discharge pipe, and the temperature of the radiant tube is easily controlled.

The operating method of the radiant tube burner system according to the invention of claim 32 is described in claims 26 to 2.
9. In the operation method of the radiant tube burner system according to any one of the items 9, when the temperature in the radiant tube is reduced, a fuel is not supplied to each burner but a cooling medium is supplied from some of the burners, and combustion is performed. The air inlet of the air for use is switched in synchronization with the alternating combustion of each burner, characterized in that it has a step of discharging from the end where no burner is arranged in the whole or a part of the input cooling medium, the temperature of the radiant tube temperature Temperature control is easy.

The method of operating the radiant tube burner system according to the invention of claim 33 is described in claims 26 to 2.
9. In the operating method of the radiant tube burner system according to any one of 9, the entire amount of the combustion exhaust gas is discharged from the end of the radiant tube burner in which the burner is not disposed while the furnace temperature does not rise to an arbitrary temperature in the alternating combustion. It is characterized by having a process, and the temperature control of the temperature inside the radiant tube is easy.

The operation method of the radiant tube burner system according to the thirty-fourth aspect is the same as that of the twelfth aspect.
9. In the operating method of the radiant tube burner system according to any one of 9, the temperature of an arbitrary place of a furnace in which the radiant tube burner system is arranged does not reach an arbitrary temperature, the burner arranged in the radiant tube is changed. The method includes a step of setting a combustion state larger than the number of ignitions in a normal operation, so that temperature control of the temperature inside the radiant tube is easy.

The method for operating the radiant tube burner system according to claim 35 is described in claims 26 to 2.
9. In the operating method of the radiant tube burner system according to any one of the items 9, while the temperature of an arbitrary place of a furnace in which the radiant tube burner system is arranged does not reach an arbitrary temperature, all the burners arranged in the radiant tube are arranged. In which the temperature of the radiant tube is easily controlled.

The operating method of the radiant tube burner system according to the invention of claim 36 is described in claims 26 to 2.
9. The operating method of the radiant tube burner system according to any one of the items 9, wherein a plurality of arbitrary temperatures are set at an arbitrary temperature of a furnace where the radiant tube burner system is arranged, and a radiant tube is set for each arbitrary temperature. The method further comprises a step of changing the number of ignitions of the burners arranged in the apparatus, and the temperature is controlled by the number of ignitions of the burners.

The operating method of the radiant tube burner system according to the invention of claim 37 is described in claims 26 to 3.
6. The operating method of the radiant tube burner system according to any one of the items 6, wherein the temperature to be controlled is a furnace temperature, or / and the radiant tube surface temperature, or / and a fluid discharged from the waste heat recovery device. And / or the temperature of the fluid discharged from the end of the radiant tube. In the present invention, the temperature in the radiant tube can be controlled from these factors.

[0053]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a radiant tube burner system of the present invention and an operation method thereof will be described in detail with reference to the drawings. FIG. 1 shows an embodiment of the radiant tube burner system of the present invention. In the same figure, radiant tube burner 5
Are mounted on both ends of the radiant tube 3, and the combustion gas passes through the inside of the radiant tube 3 and is heated.
This burner heats the inside of a heating furnace, heat treatment furnace, or the like with radiant heat radiated from its outer surface. Radiant tube 3
Is a mounting hole 7 whose pipe end is formed in the furnace wall 7 of the heating furnace.
a and is fixed so that its end is located outside the furnace. Similarly, the end of the bypass pipe 3b is disposed on the furnace wall 7. The radiant tube 3 is a bypass pipe 3b branched from a radiant tube curved in a substantially U shape.
A burner 5 is disposed at both pipe ends 3a of the radiant tube 3, and a gas cooler 9 is connected to an end of the bypass pipe 3b where no burner is disposed. The suction shutoff valve 8 and the four-way valve 4 are connected. An exhaust gas discharge pipe 19 for exhausting the exhaust gas fluid in the radiant tube 3 is provided between the exhaust gas flow control valve 6 and the exhaust gas suction cutoff valve 8. The diameter of the bypass pipe 3b is smaller than the diameter of the pipe end 3a of the radiant tube in which the burner is arranged. A plurality of tube ends 3a of the radiant tube 3 are provided, and a burner 5 is provided at each tube end.
And a plurality of bypass pipes 3b may be provided.

A burner 5 is mounted on the tube end 3a of the radiant tube 3, and a heat storage element 17 is provided in the burner body 5a.
Is provided. A burner gun 11 composed of a fuel nozzle (fuel passage) 12 and a combustion air nozzle (pilot combustion air passage) 13 through which pilot combustion air flows is inserted through the burner 5. A passage 16 is provided. A baffle 15 at the tip of the burner 5 is provided with a combustion air outlet 14.
The burner 5 is a pipe 1 in which combustion air and exhaust gas alternately flow.
0 is connected to the four-way valve 4. The exhaust gas flow control valve 6 may be manually adjusted or may be automatically controlled in accordance with a target control amount.

Further, a temperature sensor T ₁ for detecting the temperature in the furnace is provided in the heating furnace, and a temperature sensor T ₂ is provided on the side of the heat storage body 17 from which the exhaust gas is discharged. The output of the temperature sensor T _1, T ₂ are input to the control device 2. The four-way valve 4, the exhaust gas flow control valve 6, the exhaust gas suction cutoff valve 8, and the like are controlled by the control device 2. In addition, the furnace temperature measures the surface temperature of the radiant tube 3,
The temperature inside the furnace may be detected.

The burner 5 is not limited to the above embodiment, but may be the embodiment shown in FIG. Hereinafter, the burner of FIG. 2 will be described. The tube end of the radiant tube 3 has a mounting hole 7a formed in the furnace wall 7 of the heating furnace.
, The end of which is located outside the furnace, a flange 3c is provided at the end, and is fixed to a mounting portion 7b provided on the outer surface of the furnace wall 7. The gap between both ends of the radiant tube 3 and the furnace wall 7 is sealed with a sealing member (not shown), and the bypass pipe 3b is also arranged on the furnace wall 7 with the same configuration.

The burner shown in FIG. 2 is composed of a burner gun 11, a baffle 15, a heat storage unit 18 and the like. The nozzle of the burner 5 has a substantially cylindrical shape.
And a flange 15f is provided at an end thereof. The heat storage body storage part 18 bent at right angles is provided in the flange 15f. A hole 18a into which the burner gun 11 is inserted is formed in the upper part of the heat storage element storage section 18, and the heat storage element 17 or the perforated plate into which the combustion air flows and the heat storage element 17 are stacked in the heat storage element storage section 18. Housed in. A flange 18b is formed at a lower end of the heat storage body storage section 18, and the pipe 10 is connected thereto. Although not shown, the perforated plate is disposed between the heat storage unit 17 and the baffle 15, and the perforated plate closest to the baffle 15 is a portion where hot exhaust gas sucked from the combustion air injection port 14 flowing in when not operating is biased. It is arranged for the purpose of correcting the flue gas for flowing in and the flue gas for flue generated when the flue gas for combustion changes its flow into an L shape. Each heat storage body 17 is made of a material having a relatively low pressure loss of a fluid flowing through a plurality of thin tubes provided in the heat storage body 17, a large heat capacity, and a high durability, for example, a honeycomb shape formed by molding ceramics into a cylindrical shape. Is used. When the exhaust gas passes, the heat storage 17 accumulates its sensible heat, and when the combustion air passes through each heat storage 17,
The combustion air deprives the heat storage body 17 of heat and rises in temperature.

The burner gun 11 includes a fuel passage, a pilot combustion air passage, a spark plug (not shown), and the like, as in FIG. Burnagan 1
Numeral 1 denotes a pilot combustion air passage in which a fuel nozzle, which is a fuel passage, is arranged concentrically with the air passage.
8 and is supported by the baffle 15. Therefore, as shown in FIG.
1, that is, the space around the guide pipe becomes a combustion air passage 13, and the tip of the burner gun 11 reaches a position near the inner surface of the furnace wall 7 in the guide pipe. Further, in the burner 5, the heat storage bodies 17 are housed side by side in the heat storage body housing section 18, but the main combustion air passages 16 are provided.
The storage position of each heat storage body 17 is not limited to this, or in the middle of the passage of the pipe 10 of the air passage connected thereto. For example, the heat storage bodies 17 may be housed side by side around the burner gun 11. Good.

Further, the burner gun 11 in the present embodiment
The fuel supply system is described with reference to FIG. 3. A fuel supply source is connected to the burner gun 11 through a fuel supply passage 23, and a control valve 25 is interposed in the middle. The bypass passage 27 is provided to bypass the control valve 25. A flow control valve 29 and a control valve 31 are interposed in the middle of the bypass passage 27. Therefore, the fuel pumped from the fuel supply source is supplied to the burner gun 11 through the bypass passage 27 even when the control valve 25 is closed. However, in the bypass passage 27, the flow control valve 29 restricts the fuel flow in the bypass passage 27,
The fuel supplied to the burner gun 11 is adjusted by the burner gun 11 to the minimum amount required for pilot combustion.

FIG. 4 is a front view schematically showing the burner 5. The baffle 15 has a cylindrical shape, and its front surface is a disk portion 15a. The baffle 15 extends in the direction of the burner gun 11 from the entire periphery. It is composed of a peripheral wall 15b and a flange 15f. The flange 15f is fixed to the flange 3c of the radiant tube 3 and is integrally formed. The diameter of the disk portion 15a is set to substantially the same value as the inner wall of the radiant tube 3, and the disk portion 15a closes the inside of the radiant tube 3.

The disc portion 15a has a notch 15d
And a small-diameter hole 15c. This disk portion 15a
The notch 15d is formed by cutting out the lower end portion of the disk portion 15a in a half-moon shape. In the cutout 15d, the combustion air injection port (nozzle) 14 is provided eccentrically with respect to the transverse section of the radiant tube 3, and the combustion air is ejected to an eccentric position in the space inside the radiant tube 3. . In addition, the baffle 15 is disposed at a position substantially corresponding to the inner surface of the furnace wall 7 in the radiant tube 3, for example. The cutout 15d is not limited to a half-moon shape.

The small-diameter hole 15c of the disk portion 15a is opposed to the hole 18a of the heat-storage body accommodating portion 18, and its diameter is set to be substantially the same as the outer diameter of the tip of the burner gun 11. . The periphery of the small-diameter hole 15c is
, A cylindrical pipe 15e is formed, and a guide pipe that houses the burner gun 11 is arranged and supported. Therefore, the burner gun 11 is disposed substantially parallel to the radiant tube 3, and the tip is separated from the combustion air injection port 14. The peripheral wall 15b of the baffle 15 is substantially fixed to the inner peripheral surface of the radiant tube 3. The burner 5 is connected to a pipe 10 which is a combustion air passage.
An appropriate amount of combustion air is supplied to the burner 5 from a combustion air supply source (not shown) through the pipe 10.

Further, in the burner gun 11, the fuel passage 12 is disposed in the pilot combustion air passage 13, so that the pilot combustion air passage 13 is provided adjacent to the fuel passage 12. A space around the burner gun 11 is a combustion air passage 13. When the burner 5 is in a standby state in which the burner 5 is not operated, high-temperature exhaust gas flows through the combustion air passage 16. However, low-temperature (normal temperature) combustion air before combustion is always supplied into the pilot combustion air passage 13, and an amount of fuel necessary for pilot combustion flows through the fuel passage 12. In the burner 5, the fuel in the fuel passage 12 is not heated by the heat of the exhaust gas in the combustion air passage 16 to a high temperature.

When the radiant tube burner is continuously burned, the flow rate of the fluid passing through the regenerator 17 perpendicular to the burner axis is adjusted so that the heat exchange between the exhaust gas and the combustion air is balanced. Part of the surplus exhaust gas is exhausted through the bypass pipe 3b. In adjusting the flow rate distribution, the combustion air injection port 14 is defined together with the radiant tube 3 by the notch 15d. The combustion air injection port 14 is eccentric with respect to the transverse section of the radiant tube 3, and the combustion air is ejected to an eccentric position in the space inside the radiant tube 3.

Here, the relationship between the combustion air and the operation of the burner 5 will be described with reference to FIG. FIG.
FIG. 3B is a waveform showing a fuel supply cycle, and FIG. 3B is a waveform showing a combustion and exhaust cycle. In the combustion mode, the main combustion air is pumped to the burner 5 in addition to the pilot combustion air. The burner 5 is supplied with an amount of main combustion air suitable for performing main burner combustion. On the other hand, in the exhaust mode, the burner 5 is in a standby state, only the pilot combustion air is pumped, and an appropriate amount of combustion air for pilot combustion is supplied. During the pilot combustion of the burner gun 11, the combustion amount is, for example, about 5000 Kcal / H. That is, the pilot combustion air is always supplied to the pilot combustion air passage of the burner gun 11 irrespective of the operation state of the burner 5.

Next, the operation of the burner 5 will be described with reference to FIG. First, when performing pilot combustion,
The control valve 25 in the fuel supply passage 23 is closed, and fuel is supplied to the burner gun 11 only through the bypass passage 27. Combustion air is always pumped from the combustion air supply source to the burner gun 11, and the fuel and the combustion air become a mixed gas having an air ratio suitable for pilot combustion. Then, this mixed gas is ignited by an ignition plug to perform pilot combustion.

When the control valve of the fuel supply passage 23 is opened and the supply of combustion air from the combustion air supply source is started from the state where the burner gun 11 is performing pilot combustion,
The burner gun 11 performs main combustion. That is, when the control valve 25 of the fuel supply passage 23 is opened, multiple fuels are pumped from the fuel supply source to the fuel passage 12 of the burner gun 11. Then, the control valve 2 of the fuel supply passage 23 is changed from the main combustion state.
When 5 is closed, the supply of combustion air from the combustion air supply source is stopped, and the burner gun 11 returns to the state of performing pilot combustion. Even in this state, a small amount of fuel is supplied to the burner gun 11 via the bypass passage 27 of the fuel supply passage 23, and the combustion air supply source always supplies combustion air. The burner gun 11 performs stable pilot combustion. By alternately performing the operations as described above, alternating combustion is performed.

Next, the alternating combustion of the pair of burners 5 will be described with reference to FIG. It is to be noted that a description will be given by giving A to a code related to the operation of one burner and B to a code related to the other burner. A large amount of fuel and primary combustion air and pilot air for combustion is supplied to the burner 5A, the main combustion is performed as shown in the flame F _1. on the other hand,
The Banagan 11B burner 5B is a small amount of fuel and Pairoto combustion air is supplied, the pilot combustion F ₂ is performed. In the burner 5B even in the standby state, the fuel and the pilot combustion air in an amount suitable for the pilot combustion is supplied, and combustion as indicated by the pilot flame F _2.

The exhaust gas generated by the main combustion of the burner 5A is heated while flowing in the radiant tube 3, and flows toward the burner 5B. This exhaust gas flows into the main combustion air passage 16B from the main combustion air injection port 14B of the baffle 15B, and is discharged through the air passage pipe 10. At this time, the exhaust gas is burner body 5aB
The heat is recovered by each of the heat storage elements 17B in the
The temperature of B rises.

When the burner 5A starts the main combustion and a predetermined time T (for example, about 20 seconds) has elapsed, the control valve 25A of the fuel supply passage 23A is closed as shown in FIG. The control valve 25B of the supply passage 23B opens.
At the same time, the four-way valve 4 is switched, the burners 5A and 5B on the operating side and the standby side are switched, the main combustion is performed by the burner 5B, and the pilot combustion is performed on the burner 5A.

FIGS. 6 (a) and 6 (b) show the above-mentioned alternating combustion in operation waveforms. At time t1, the burner 5A starts the main combustion and the burner 5B starts the pilot combustion. Then, at time point t2 when the time T has elapsed, the burner 5A that has been performing main combustion is switched to pilot combustion, and the burner 5B that has been performing pilot combustion starts main combustion. Thereafter, each time the time T elapses, the burners 5A and 5B on the operating side and the standby side are switched, and the radiant tube burner 1 performs alternating combustion.

Next, the cooling pipe mode in this embodiment will be described with reference to FIG. The furnace temperature is monitored by the control device _{2 for} the outputs of the temperature sensors T ₁ and T ₂ , and the operation mode when the furnace temperature exceeds the set temperature or when the emergency operation is stopped is the cooling pipe mode. In the basic operation of this mode, the combustion of the burners 5 at both ends is stopped to keep the fuel shut off, and the fuel supply to the pilot burner is also shut off. Further, the exhaust gas passing through the regenerator 17 is shut off by fully closing the exhaust gas suction shutoff valve 8 disposed at the exhaust port of the four-way valve 4, setting the four-way valve 4 to an intermediate position, and closing both pipe ends. Combustion air as a cooling medium is passed through the radiant tube 3 from the burner 3a, and the entire amount of the combustion air as a cooling medium is exhausted through a bypass pipe 3b to cool the radiant tube.

In this embodiment, the furnace temperature is measured by the temperature sensors T ₁ and T ₂ while operating in the cooling pipe mode, and the result of processing by the controller 2 indicates that the furnace temperature reaches the control target value. Then, stop blowing the combustion air. Thereafter, when the furnace temperature is lower than the target furnace temperature lower limit value, the burner 5 is switched to the combustion mode again to start combustion. Also, when the furnace temperature recovers and exceeds the upper limit of the target furnace temperature, the operation is similarly performed in the cooling pipe mode. Even in such steady combustion, the cooling pipe mode is used as a means for controlling the temperature. Further, the radiant tube can be operated independently in the cooling pipe mode. The cooling medium is, for example, a non-flammable fluid such as air, sinter, or combustion gas, or a mixed fluid thereof, and a material that does not cause a fire explosion even when the furnace temperature is high is selected.

In this embodiment, an exhaust gas flow control valve 6 for adjusting the amount of fluid discharged from the end of the bypass pipe 3b is provided, and the exhaust gas in the radiant tube 3 is stored in the radiant tube 3 via the bypass pipe 3b. Since the amount flowing to the body 17 can be adjusted, the sensible heat of the exhaust gas absorbed by the heat storage body 17 and the sensible heat obtained by the combustion air can be balanced. It is possible to exchange the heat quantity between the exhaust gas and the combustion air, that is, to make the water equivalent the same, and 100%
Even when the combustion is continuously performed with the combustion load, the temperature of the exhaust gas on the regenerator outlet side does not abnormally increase, and the adjustment for enabling the continuous combustion at the highest thermal efficiency operating point can be performed.

In the radiant tube burner system of the present embodiment, the radiant tube cooling means can function as a cooling pipe in an emergency when the temperature is abnormally high. In such an emergency, in order to rapidly lower the furnace temperature, no fuel is supplied to each burner 5 and the cooling medium is supplied into the radiant tube 3 from all or some of the burners. By discharging the whole or a part of the supplied cooling medium from the bypass pipe 3b of the radiant tube in which the burner 5 is not disposed, the temperature in the radiant tube can be rapidly reduced.

When the cooling medium is discharged from the tube end 3b of the radiant tube, the room temperature air is continuously supplied even if the high-temperature preheating air is supplied from the heating mode to the cooling pipe mode. Can be supplied to the heat storage 17. In the cooling pipe mode, after the heat stored in the heat storage unit 17 is released at the initial stage, the room temperature air can be supplied into the radiant tube 3 also through the heat storage unit 17. Of course, in the case where the operation of discharging the cooling medium through the burner 5 and the operation of discharging the cooling medium from the end of the bypass pipe 3b are both controlled, the temperature of the cooling medium to the radiant tube 3 can be adjusted, and the cooling capacity can be controlled. become. Further, the cooling capacity can be changed by changing the number of the burners 5 and / or the amount of immersion of the cooling medium through the burners 5.

Further, the control device 2 is provided with control means for controlling the furnace temperature. In the cooling pipe mode, the present furnace is used as an index for controlling the amount of heat removed from the furnace. The deviation between the internal temperature and the target furnace temperature to be reduced can be calculated and used. With this deviation, the cooling medium temperature can be adjusted. That is, it is possible to control the ratio of the amount of exhaust gas discharged from the burner 5 to the amount of exhaust gas output from the bypass pipe 3b, the number of burners 5 into which the cooling medium is injected, and the amount of cooling medium input.

Further, the controller 2 can use the amount of reduction in the furnace temperature per unit time as an index when controlling the amount of heat removal by which the cooling pipe removes heat from the furnace. The above-mentioned cooling medium temperature adjustment, that is, control of the ratio of the amount of discharge from the burner 5 to the amount of discharge from the bypass pipe 3b, the number of burners into which the cooling medium is injected, and / or the number of the cooling medium are determined by the furnace temperature reduction amount per unit time. Control of the input amount is possible.

At this time, when the combustion is continuously performed with the radiant tube burner capacity, a part of the exhaust gas which becomes excessive in heat exchange is exhausted through the bypass pipe 3b so that the exchange heat of the exhaust gas and the combustion air is balanced in the regenerator 17. Can be adjusted to When used as a cooling pipe, the exhaust gas flow control valve 6 may be an automatic valve that can be controlled at two positions so as to be fully open, and may be of a type in which the fully open and combustion modes are intermediate positions. Further, the opening degree of the exhaust gas flow control valve 6 may be controlled by a method capable of more delicate control of the exhaust gas bypass amount.

Further, when lowering the furnace temperature, no fuel is supplied to each burner 5 or a cooling medium is supplied from some of the burners 5, and the air inlet is switched by switching each burner 5 alternately. Means are provided for discharging the whole or a part of the input cooling medium from the end of the bypass pipe 3b in synchronization with the alternating combustion to be burned. By such means,
When cooling air is constantly blown, a temperature difference occurs between the inner and outer surfaces of the radiant tube, and if the temperature difference is large, cracks may occur in the radiant tube. By operating while supplying the cooling air or stopping the supply of the cooling air, the temperature difference between the inner and outer surfaces of the radiant tube can be reduced, and the generation of cracks in the radiant tube can be avoided. In the cooling pipe mode, the operation mode can be switched only by shutting off the fuel at the time of alternating combustion, so that the basic operation sequence and the cooling mode are shared instead of the two types of sequences, the heating mode and the cooling mode. It is a control system that can.

Further, in this embodiment, the gas cooler 9 is provided, and the combustion exhaust gas discharged from the pipe end of the bypass pipe 3b can be cooled and discharged by the gas cooler 9, so that the exhaust gas discharge pipe 19 is provided. No abnormal high temperature condition.

In the radiant tube burner system according to the present embodiment, when the furnace is started from a low temperature and heated, the entire amount of exhaust gas is transferred to the end of the bypass pipe 3b while the furnace temperature does not reach an arbitrary temperature. Since the burner containing the heat accumulator is not inserted into the end of the bypass pipe 3b, dew condensation in the burner can be prevented. Therefore, it is possible to minimize the equipment breakage due to low-temperature corrosion.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, in the embodiment of FIG. 7, the gas cooler for cooling the combustion exhaust gas discharged from the bypass pipe 3 b is not provided, and the bypass pipe 3 b protrudes from the furnace wall 7 and passes through the exhaust gas flow control valve 6 to the four-way valve 4.
It is connected to the. An exhaust gas discharge pipe 19 is provided between the four-way valve 4 and the passing gas flow control valve 6. Since the basic combustion operation is the same as described above, the description is omitted. However, the exhaust gas flow control valve 6 is made of a heat-resistant metal, and is configured so as not to hinder the passage of the exhaust gas. For example,
In the radiant tube burner 1, switching of the operation standby state of each burner 5 is repeated every T time. However, the present invention is not limited to this. The temperature of each of the heat storage bodies 17A and 17B is monitored, and this temperature is set to the set temperature. At this point, the operation of each of the burners 5A and 5B and the standby may be manually switched.

FIG. 8 shows another embodiment of the radiant tube burner system of the present invention. FIG. 8 shows a heating furnace composed of heating zones Z ₁ , Z ₂ , Z ₃ ..., And a radiant tube 3 having a U-shaped tube end 3a and two bypass tubes 3b for each heating zone. Equipped. Assuming that the furnace width is L, the pipe end 3a in the furnace of the radiant tube 3 and the two bypass pipes 3b have a length La in the furnace.
Are in a relationship of La> L / 2. Note that the same configuration is used in the above embodiment. In these heating zones, the furnace temperature can be controlled independently for each heating zone. Further, since the number of pipe ends where the burners 5 are arranged can be two or more, it is possible to switch the combination of the alternating combustion of the paired burners and burn.
More specifically, when burners are mounted at four locations of the radiant tube 3, any two of the burners are set to the combustion state at the four locations, and the other two locations are set to the exhaust state. The part is set to a combustion state, and the other three parts are set to an exhaust state. In the next cycle, by controlling the three places to be in the combustion state and the other one to be in the exhaust state, it is possible to prevent the radiant tube from being locally heated. These switching controls are performed by the controller 2
Can be controlled by Of course, the detection of the furnace temperature is the same as in the above embodiment, and the operation in the cooling pipe mode is also the same as in the above embodiment.

Further, by providing a drain discharge device 20 in the exhaust gas discharge pipe 19, drain generated in the radiant tube can be discharged. The drain discharge device 20 is a device that discharges dew condensation of an acidic substance or the like generated when the temperature in the radiant tube suddenly decreases. The drain discharge device 20 prevents corrosion of the radiant tube, reduces the temperature rapidly due to drain, and the like. An adverse effect can be prevented. Further, the drain discharge device 20 may be provided near the regenerative burner 17. Further, by providing a means for discharging drain outside the radiant tube burner system of the present embodiment, the residence time of the acid-corrosive fluid in the system can be minimized, and equipment destruction due to low-temperature corrosion can be minimized.

Needless to say, in the present embodiment, in the cooling pipe mode, it is possible to discharge the entire amount of the combustion exhaust gas from the bypass pipe without passing the combustion exhaust gas through the regenerator while monitoring the temperature inside the furnace to monitor the occurrence of dew condensation. Therefore, equipment destruction due to low-temperature corrosion can be minimized.

Further, in the present embodiment, in the radiant tube burner system provided for each zone of the heating furnace, while the temperature of each zone of the heating furnace in which the radiant tube burner system is arranged does not rise to a predetermined temperature, It is possible to increase the amount of combustion by increasing the number of burners arranged in the radiant tube more than the number of ignitions during normal operation.The heat load on the radiant tube is within the range of the burner capacity even without sensible heat of preheated air. It is possible to increase with.

Further, in the radiant tube burner system of the present embodiment, the furnace temperature of any zone of the heating furnace in which the radiant tube burner system is arranged is set to an arbitrary temperature for each zone, and each arbitrary temperature is set for each zone. By changing the number of ignitions of the burners arranged in the radiant tube, it is possible to increase the heat load of the radiant tube to the total combustion amount of each burner arranged in the radiant tube. The minimum heat load can also be the minimum combustion of one of the burners located in the radiant tube. Also,
By setting the temperature in the furnace in the zone, a control target value is set and heat load control becomes possible.

Another embodiment of the radiant tube burner system of the present invention will be described with reference to FIG. In the figure, the radiant tube burner 1 is
The radiant tube burner of the above embodiment is arranged in the opening 7b in which the furnace wall 7 is perforated, on the small fireproof wall 7c equivalent to the opening corresponding to the opening, and from the furnace wall 7 to the small fireproof wall 7c.
Each time, the maintainability is improved as a detachable structure. Also, by installing the radiant tube burner into the small fireproof wall 7c and then attaching the small fireproof wall 7c to the opening 7b, a radiant tube burner combustion furnace can be constructed. In addition, the small fireproof wall 7c can be detached from the opening 7b to repair and maintain the radiant tube burner.

The heat storage body used in the burner of the present embodiment is not limited to the honeycomb heat storage body, but may be of any shape and material such as ceramics and metals such as balls and blocks. The radiant tube burner used in the present embodiment is not limited to the U-shape, but may be any shape such as a W-type or an S-type, a fin on the surface, and a cross-sectional shape of any shape.

[0091]

As described above, according to the present invention,
By providing a bypass pipe in the radiant tube and discharging the exhaust gas from the bypass pipe, there is an advantage that the temperature inside the radiant tube can be easily raised and cooled.

Also, by causing a pair of burners to be alternately burned in the radiant tube and installing at least one pair of burners and switching the paired burners, it is possible to prevent the radiant tube temperature from locally increasing. There is an advantage that a fire occurrence factor can be reduced.

Further, the thermal efficiency of the radiant tube burner system is improved, and the combustion exhaust gas can be reduced and discharged by the gas cooler provided in the bypass pipe. Therefore, there is an advantage that the temperature can be rapidly reduced.

The amount of fluid discharged from the end of the bypass pipe is adjusted by exhaust gas flow rate adjusting means to balance the sensible heat emitted by the exhaust gas from the heat accumulator with the sensible heat obtained by the combustion air. There is an advantage that even when the fuel is continuously burned at a combustion load of approximately 100%, the temperature of the exhaust gas at the heat storage body outlet does not rise abnormally, and the operation can be performed with the thermal efficiency maintained at the maximum.

Further, there is an advantage that the operation state can be switched continuously from the heating mode to the cooling pipe mode or from the cooling pipe mode to the heating mode. Also, the cooling capacity can be changed by changing the number of burners into which the cooling medium is injected and / or the amount of the cooling medium immersed, and the temperature can be rapidly lowered. In addition, the length of the bypass tube in the furnace is equal to or more than half the width of the furnace, and the bypass tube plays the role of a heat radiation tube in the furnace. I can do it.

Further, by using the amount of temperature reduction in the furnace per unit time as an index for controlling the amount of heat removed by the cooling pipe from the furnace, the amount of cooling medium discharged from the burner and the amount of bypass can be reduced. It is possible to control the discharge ratio from the pipe, control the number of burners into which the cooling medium is charged, and / or control the amount of the cooling medium charged, and easily adjust the temperature of the furnace.

Further, if cooling air is constantly blown, a temperature difference is generated between the inner and outer surfaces of the radiant tube, and if the temperature difference is large, a crack is generated in the radiant tube. By injecting the cooling air into the click, the temperature difference between the inner and outer surfaces of the radiant tube can be reduced, and the radiant tube can be prevented from cracking.

In the cooling pipe mode, the cooling mode can be set only by shutting off the fuel even in the use state of the heating mode without providing a special sequence. Since these modes can be incorporated in the sequence, an inexpensive control system can be provided.

When the furnace is started up from a low temperature and heated, the entire amount of exhaust gas can be discharged from the end of the radiant tube where no burner is provided unless the temperature reaches an arbitrary temperature.
Since the combustion exhaust gas can be discharged without passing through a burner in which a complicated heat storage element is incorporated, dew condensation in the burner can be prevented, and the equipment breakage due to low-temperature corrosion can be minimized. Of course, the same effect can be obtained when the furnace temperature is changed from high to low. Further, by providing a means for discharging the drain outside the radiant tube burner system, there is an advantage that the residence time of the acid-corrosive fluid in the system can be minimized and equipment destruction due to low-temperature corrosion can be minimized.

Further, in the radiant tube burner system, a large number of burners are installed, and a range of the combustion amount from the total maximum combustion amount to the minimum combustion amount of one burner can be provided. As in the case of the radiant tube, there is an advantage that a large turndown can be realized as compared with the turndown of one burner (operation for lowering the temperature).

Further, since the diameter of the radiant tube without the burner is smaller than the diameter of the radiant tube with the burner, the exhaust gas flow rate is small due to the loss of the radiant tube, the heat transfer coefficient in the tube is improved, and the heat radiation into the furnace is improved. Ability is improved.

Further, by providing a structure in which the refractory wall on which the radiant tube burner is mounted can be attached to and detached from the opening of the furnace wall, there is an advantage that maintainability and construction are facilitated. Further, the present invention is a radiant tube burner system having all the above effects.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a radiant tube burner system of the present invention.

FIG. 2 is a sectional view showing an embodiment of a radiant tube burner system applied to the present invention.

FIG. 3 is a system diagram showing a fuel supply passage of the present embodiment.

FIG. 4 is a front view of the radiant tube burner according to the embodiment of the present invention as viewed from a front end direction.

FIG. 5 is an explanatory diagram illustrating a relationship between a combustion state and an air supply amount according to the present embodiment.

FIG. 6 is an explanatory diagram showing alternating combustion according to the embodiment.

FIG. 7 is a configuration diagram showing another embodiment of the radiant tube burner system of the present invention.

FIG. 8 is a configuration diagram showing another embodiment of the radiant tube burner system of the present invention.

FIG. 9 is a configuration diagram showing another embodiment of the radiant tube burner system of the present invention.

FIG. 10 is a configuration diagram of a conventional radiant tube burner system.

FIG. 11 is a configuration diagram of a conventional radiant tube burner system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Radiant tube burner 2 Controller 3 Radiant tube 3a Pipe end 3b Bypass pipe 4 Four-way valve 5 Burner 6 Exhaust gas flow control valve 9 Gas cooler 7 Furnace wall 8 Exhaust gas cutoff valve 10 Piping 11 Burner gun 12 Fuel nozzle (fuel passage) 13 Pilot combustion Air passage for combustion 14 Air injection opening for combustion 15 Baffle 16 Air passage for combustion 17 Heat storage material 18 Heat storage material storage part 19 Pipe for exhaust gas discharge

Continued on the front page (72) Inventor Suga Politics 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Inside Nihon Kokan Co., Ltd. (72) Inventor Ryoichi Tanaka 2-1-1, Shirite, Tsurumi-ku, Yokohama-shi, Kanagawa Japan Furnace Within Industrial Co., Ltd. (72) Inventor Mamoru Matsuo 2-1-153 Shirite, Tsurumi-ku, Yokohama-shi, Kanagawa Japan Furnace Industrial Co., Ltd.

Claims (37)

[Claims] 1. The radiant tube burner system has three
Comprising a radiant tube having more than two ends,
A burner having waste heat recovery means is arranged at at least two places of the end, and a fluid flowing into the radiant tube from the remaining end where no burner is arranged is used to switch a flow path between combustion exhaust gas and combustion air. A radiant tube burner system characterized in that the exhaust gas is discharged to a pipe for exhaust gas discharge without passing through a switching valve. 2. The radiant tube burner system according to claim 1, wherein the waste heat recovery means is a heat storage material having air permeability or a heat storage material and a perforated plate. 3. The radiant tube burner system according to claim 1, wherein a cooling means for cooling combustion exhaust gas is provided in a pipe line from an end of the radiant tube where no burner is provided to the exhaust gas discharge pipe. Radiant tube burner system. 4. The radiant tube burner system according to claim 1, wherein a length of the radiant tube in which a burner is not disposed has a length equal to or more than 炉 of a furnace width. Radiant tube burner system. 5. The radiant tube burner system according to claim 1, wherein the exhaust gas discharge pipe is provided between a pipe from an end of the radiant tube where no burner is disposed to the exhaust gas discharge pipe. A radiant tube burner system comprising a flow rate adjusting means for adjusting an amount of fluid discharged from the radiant tube burner. 6. The radiant tube burner system according to claim 1, 2, 3, 4, or 5, wherein the fluid that has passed through the waste heat recovery means is discharged from an end of the radiant tube where no burner is provided. A radiant tube burner system, characterized in that flow rate adjusting means for adjusting a fluid and merging and discharging each fluid is provided between the exhaust gas discharge pipe and the exhaust gas discharge pipe. 7. The radiant tube burner system according to claim 1, 2, 3, 4, 5, or 6, wherein a refractory wall structure equivalent to the furnace wall corresponding to an opening provided in the furnace wall of the heating furnace. The radiant tube burner system is characterized in that the radiant tube is mounted on the small refractory wall of (1), and the small refractory wall on which the radiant tube is mounted is detachable from the opening. 8. A radiant tube having three or more ends; a burner disposed at at least two places on the end and having waste heat recovery means; supplying combustion air to the burner; A switching valve for alternately switching the discharge of the combustion exhaust gas from the exhaust pipe to the exhaust gas discharge pipe; cooling means for lowering the temperature of the fluid discharged from the end of the radiant tube without a burner; and cooling by the cooling means Flow rate adjusting means for adjusting the flow rate of the discharged fluid; suction exhaust gas shutoff means for discharging the fluid in the radiant tube from the exhaust gas discharge pipe from the end of the radiant tube where no burner is disposed; and alternately burning the burner. Together with the suction exhaust gas blocking means,
A control device for controlling the temperature in the radiant tube by operating the flow rate adjusting means and the suction exhaust gas shutoff means. 9. The radiant tube burner system according to claim 1, further comprising a temperature control unit that supplies a cooling medium into the radiant tube and adjusts a temperature inside the radiant tube. A radiant tube burner system. 10. The radiant tube burner system according to claim 9, wherein the temperature control means supplies a cooling medium into the radiant tube from all or some of the burners without supplying any fuel to each of the burners. A radiant tube burner system, characterized in that the radiant tube burner system is a means for discharging the whole or a part of the supplied cooling medium from the end where no burner is provided through the exhaust gas discharge pipe. 11. The radiant tube burner system according to claim 9, wherein the temperature control means is means for changing the number of burners into which the cooling medium is charged and / or the amount of the cooling medium charged. Radiant tube burner system. 12. The radiant tube burner system according to claim 9, wherein the temperature control means controls the supply amount of the cooling medium based on a deviation between a current furnace temperature and a target furnace temperature to be reduced. A radiant tube burner system, characterized in that: 13. The radiant tube burner system according to claim 9, wherein the temperature control unit is a unit that controls a supply amount of the cooling medium based on a reduction amount in the furnace temperature per unit time. Radiant tube burner system. 14. The radiant tube burner system according to claim 9, wherein the temperature control means inputs a cooling medium from some of the burners without inputting any fuel to each burner, and inputs air for combustion. A radiant tube burner characterized by being a means for lowering the furnace temperature by switching the burner by switching each burner alternately, discharging the coolant from the end of the radiant tube in which the burner is not arranged in all or a part of the supplied cooling medium, and lowering the furnace temperature. system. 15. The radiant tube burner system according to claim 9, wherein the temperature control means supplies a cooling medium into the radiant tube burner while the temperature in the furnace does not reach a set temperature, and supplies the radiant to the radiant tube burner. A radiant tube burner system characterized in that the radiant tube burner system is means for discharging the entire amount of combustion exhaust gas in the tube from the end of the radiant tube where no burner is provided. 16. The radiant tube burner system according to claim 9, wherein the cooling medium is a non-flammable fluid such as air, nitrogen, combustion gas, or a mixed fluid thereof. Radiant tube burner system. 17. The radiant tube burner system according to claim 1, further comprising: a drain discharge device configured to discharge a drain in a fluid discharged from the radiant tube. Burner system. 18. The radiant tube burner system according to claim 1, wherein the radiant tube burner system has a radiant tube burner system in which the radiant tube burner system is arranged in a heating furnace at an arbitrary temperature that does not reach a predetermined temperature. A radiant tube burner system comprising a control means for setting a burner disposed in a combustion state by the number of ignitions greater than the number of ignitions during normal operation. 19. The radiant tube burner system according to claim 1, wherein said radiant tube burner system has a radiant tube burner system in which said radiant tube burner system has a radiant tube burner as long as its temperature does not reach a predetermined temperature. A radiant tube burner system comprising control means for igniting all burners disposed in the radiant tube burner system. 20. The radiant tube burner system according to claim 1, wherein a plurality of predetermined temperatures are set at any temperature of a heating furnace in which the radiant tube burner system is arranged. A radiant tube burner system comprising control means for changing the number of ignitions of burners arranged in a radiant tube for each temperature of the radiant tube. 21. The radiant tube burner system according to claim 1, further comprising control means for raising or lowering the furnace temperature depending on the furnace temperature in each zone of the heating furnace. Radiant tube burner system. 22. The radiant tube system according to any one of claims 1 to 17, further comprising control means for adjusting a temperature in the furnace according to a temperature of a fluid discharged from an end of the radiant tube. Features a radiant tube burner system. 23. The radiant tube burner system according to claim 1, further comprising control means for adjusting a furnace temperature according to a surface temperature of the radiant tube. 24. The radiant tube burner system according to claim 1, further comprising control means for adjusting the temperature in the furnace according to the temperature of the fluid discharged from the waste heat recovery means. Radiant tube burner system. 25. The radiant tube burner system according to claim 1, wherein a diameter of a tube end of the radiant tube where no burner is arranged is smaller than a diameter of the radiant tube where a burner is arranged. Radiant tube burner system. 26. A method for operating a radiant tube burner system, comprising: arranging a burner having waste heat recovery means at at least two or more of three or more ends of the radiant tube to perform alternating combustion; When lowering the temperature in the radiant tube, the flue gas discharged from the pipe end of the radiant tube in which a burner is arranged, without passing through a switching valve for switching between the flue gas and the combustion air, the flue gas discharge pipe. Discharging the air through the radiant tube to lower the temperature in the radiant tube. 27. A method for operating a radiant tube burner system, comprising: arranging a burner having waste heat recovery means at at least two or more of three or more ends of the radiant tube to perform alternating combustion; When lowering the temperature in the radiant tube, a cooling medium is caused to flow into the radiant tube, and the combustion exhaust gas discharged from the tube end of the radiant tube in which a burner is arranged is cooled. Discharging the exhaust gas from the exhaust pipe without passing through a switching valve for switching to lower the temperature inside the radiant tube, thereby operating the radiant tube burner system. 28. A method for operating a radiant tube burner system, comprising: arranging a burner having waste heat recovery means at at least two or more of three or more ends of the radiant tube to perform alternating combustion; When lowering the temperature inside the radiant tube, charge the cooling medium from all or some burners without putting any fuel into each burner, and transfer all or part of the input cooling medium from the end where no burners are arranged. Discharging the radiant tube burner system. 29. A method for operating a radiant tube burner system, comprising: arranging a burner having waste heat recovery means at at least two or more of three or more ends of the radiant tube to perform alternating combustion; Controlling the furnace temperature based on the difference between the current furnace temperature and the target furnace temperature when lowering the temperature inside the radiant tube. 30. The method for operating a radiant tube burner system according to claim 26, further comprising a step of controlling the temperature in the radiant tube based on an amount of change in the furnace temperature per unit time. A characteristic method of operating a radiant tube burner system. 31. The operating method of the radiant tube burner system according to claim 26, wherein the fluid discharged from the end where no burner is disposed, the waste heat recovery means and the four-way valve are passed. A method for operating a radiant tube burner system, comprising a step of adjusting a flow rate of a fluid and merging and discharging the exhaust gas from a pipe for exhaust gas discharge. 32. The operating method of the radiant tube burner system according to claim 26, wherein when lowering the temperature in the radiant tube, no fuel is supplied to each burner and a part of the burner is not charged. A step of injecting a cooling medium from a burner, switching the air inlet of combustion air in synchronization with the alternating combustion of each burner, and discharging the air from the end where no burner is arranged in all or a part of the injected cooling medium. A method for operating a radiant tube burner system, comprising: 33. The operating method of the radiant tube burner system according to claim 26, wherein, in the alternating combustion, a burner is disposed for all the combustion exhaust gas while the furnace temperature does not rise to an arbitrary temperature. A method for operating a radiant tube burner system, comprising the step of discharging the radiant tube burner from the end of the radiant tube burner. 34. The method for operating a radiant tube burner system according to claim 26, wherein the temperature of an arbitrary place of a furnace in which the radiant tube burner system is arranged does not reach an arbitrary temperature. A method for operating a radiant tube burner system, comprising a step of setting a burner disposed in the radiant tube to a combustion state larger than the number of ignitions during normal operation. 35. The method for operating a radiant tube burner system according to any one of claims 26 to 29, wherein a temperature of an arbitrary place of a furnace in which the radiant tube burner system is arranged does not reach an arbitrary temperature. A method for operating a radiant tube burner system, comprising the step of igniting all burners disposed on the radiant tube. 36. The operating method of a radiant tube burner system according to claim 26, wherein a plurality of arbitrary temperatures are set to an arbitrary temperature of a furnace in which the radiant tube burner system is arranged. A method for operating a radiant tube burner system, comprising a step of changing the number of ignitions of burners arranged in a radiant tube for each of the arbitrary temperatures. 37. The operating method of the radiant tube burner system according to claim 28, wherein the temperature to be controlled is a furnace temperature, and / or a surface temperature of the radiant tube, and / or A method for operating a radiant tube burner system, comprising: a temperature of a fluid discharged from a waste heat recovery device and / or a temperature of a fluid discharged from an end of the radiant tube.