JP2004012046A - Combustion control method for heat storage type burner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To safely carry out burner combustion without generating any unburnt gas. <P>SOLUTION: In this controlling method for heat storage type burner combustion, a plurality of radiant tube type heat storage burners 4 are arranged in respective zones 6 in a heating furnace 3, and burner combustion gas 18 fed by each zone unit is burnt alternately by a pair of burners 7a and 7b in each heat storage type burner belonging to each zone for heating the heating furnace, while heat is accumulated in a heat accumulation zone in the burner operating no combustion in a pair of the burners by emission gas after heating. In ignition of the each heat storage type burner 4 belonging to the each zone, pilot combustion gas 16 is supplied to the respective heat storage type burners for igniting a pilot 13, and when a predetermined multiple of burner combustion gas 18 of the pilot combustion gas 16 is fed to the respective heat accumulation type burners, all the heat storage type burners belonging to the corresponding zone are ignited at the same time. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a regenerative burner combustion control method in which a heating furnace is indirectly heated by a radiant tube by a number of regenerative burners.
[0002]
[Prior art]
FIG. 11A is a perspective view showing a schematic configuration of a radiant tube heating furnace incorporated in a continuous steel sheet processing line in an iron making plant. FIG. 11B is a schematic diagram viewed from above, and FIG. 11C is a schematic diagram viewed from the side. The steel sheet 1 conveyed through the continuous processing line is guided into the heating furnace 3 via the carry-in roll 2a. In the heating furnace 3, a large number of rolls 2c and 2d are provided at predetermined intervals, each being divided into an upper part and a lower part. The steel sheet 1 introduced into the heating furnace 3 passes between the rolls 2c and 2d, and is carried out of the heating furnace 3 via the carry-out roll 2b.
[0003]
A large number of regenerative burners 4 are embedded in the side walls 3 a on both sides of the heating furnace 3 so as to penetrate the side walls 3 a into the heating furnace 3. Then, the flame of the regenerative burner machine 4 flows through the radiant tube 5 protruding into the heating furnace 3. The steel sheet 1 passing between the rolls 2c and 2d is indirectly heated by the heat of the flame flowing through the radiant tube 5.
[0004]
Generally, the inside of the heating furnace 3 is divided into a plurality of zones 6, and the temperature of the steel sheet 1, that is, the heating temperature is controlled for each zone 6. Each zone 6 includes a plurality of regenerative burner machines 4 and radiant tubes 5 connected to the regenerative burner machines 4. Therefore, the steel sheet 1 introduced into the heating furnace 3 is sequentially heated in each zone 6 and then carried out of the heating furnace 3.
[0005]
FIG. 12 is a schematic cross-sectional view showing a schematic configuration of each regenerative burner machine 4 attached to the outer wall 3a of each zone 6 of the heating furnace 3.
[0006]
Cylindrical burners 7a and 7b are attached to the inner surface of the side wall 3a of the heating furnace 3 at each opening of a radiant tube 5 formed in a substantially U-shape toward the inside of the heating furnace 3, and cylindrical burners 7a and 7b are attached to the burners 7a and 7b. Are connected. In the burners 7a, 7b and the tropics 8a, 8b, a flow path 9 for the combustion air 21, a flow path 14a, 14b for the pilot air 15, and a flow path 10 for the combustion gas 18, 16 are formed. In each of the burners 7a and 7b, ignitions 11a and 11b for performing ignition of the pilot 13 and detection of the ignition are provided.
[0007]
The burner fuel gas 18 is supplied to the burners 7a and 7b via the burner fuel gas shutoff valves 17a and 17b, and the pilot combustion gas 16 is supplied to the burners 7a and 7b via the pilot combustion gas shutoff valves 20a and 20b. On the other hand, the burner combustion air 21 is supplied to the burners 7a and 7b via a common burner combustion air cutoff valve 23 and a switching valve 24. Further, the pilot combustion air 15 is supplied to the burners 7a, 7b via the supply pipes 14a, 14b.
[0008]
Therefore, in the regenerative burner machine 4, a nozzle dedicated to the pilot 13 is not provided, and the pilot 13 and the regular flame 12 are burned by the same burners 7a and 7b.
[0009]
In the regenerative burner machine 4 having such a configuration, both the burners 7a and 7b do not go into the combustion state at the same time, and only one of the burners 7a and 7b goes into the combustion state. The flame 12 generated by the burner 7a during combustion passes through the radiant tube 5, and is exhausted through the other burner 7b (burner during exhaust), the flow path 9 of the tropical heat storage 8b, and the switching valve 24 shown in FIG. The gas 25 is exhausted to the outside. While the exhaust gas 25 flows through the flow path 9 of the tropical storage 8b, the standby tropical storage 8b and the burner 7b are kept at a high temperature (during the exhaust).
[0010]
For example, when a certain time such as 30 seconds has elapsed, the supply of the burner fuel gas 18 to the burning burner 7a is stopped, and the supply of the burner fuel gas 18 to the other exhaust burner 7b is started. At the same time, the switching valve 24 is switched to switch the burner combustion air 21 to the other exhausting burner 7b. Then, the burner 7b is ignited, and the flame 12 generated by the burner 7b passes through the radiant tube 5, and passes through the other burner 7a and the flow path 9 of the tropical heat storage 8a, and the switching valve 24 in a state opposite to that of FIG. The gas is exhausted to the outside as exhaust gas 25 via. In the process of the exhaust gas 25 flowing through the flow path 9 of the tropical zone 8a, the tropical zone 8a and the burner 7a during this exhaust (standby) are kept at a high temperature.
[0011]
By burning the burners 7a and 7b alternately in this way, the hot-air storing parts 8a and 8b and the exhaust burners 7a and 7b can be maintained at a high temperature, and thus the combustion and the exhaust of the burners 7a and 7b are switched. Can be performed in a short time and efficiently.
[0012]
A method for controlling the combustion of each regenerative burner unit 4 of the heating furnace 3 to which a plurality of regenerative burner units 4 having such a configuration and functions are attached will be described.
[0013]
(A) Ignition and extinguishing of regenerative burner 4
Each regenerative burner unit 4 belonging to each zone 6 of the heating furnace 3 is ignited and extinguished in each zone 6 unit. That is, first, the pilot combustion gas shutoff valves 20a, 20b are opened to supply the pilot combustion gas 16 to each burner 7a, 7b, and both the burners 7a, 7b in all the regenerative burner machines 4 belonging to the zone 6 are opened. Is ignited by the ignitions 11a and 11b. Next, the switching valve 24 of the regenerative burner machine 4 is operated to select the burners 7a and 7b to be ignited. Thereafter, the burner combustion gas 18 and the burner combustion air 16 are sequentially supplied to each regenerative burner machine 4. As a result, each regenerative burner machine 4 is sequentially ignited.
[0014]
In this case, the minimum burner fuel gas and the minimum burner combustion air predetermined for each zone are continuously supplied from the first ignition of the regenerative burner unit 4 to the ignition of the last regenerative burner unit 4. When the ignition of all the regenerative burners 4 is completed, the burner combustion gas and the burner combustion air are respectively raised to the burner combustion gas and the burner combustion air corresponding to the heating temperature of the zone 6.
[0015]
When extinguishing each regenerative burner unit 4, the burner combustion gas and burner combustion air of each regenerative burner unit 4 are simultaneously shut off, and the regenerative burner units 4 are extinguished simultaneously.
[0016]
(B) Switching between combustion and exhaust of each burner of the regenerative burner machine 4
The switching between the combustion and the exhaust of the burners 7a and 7b of each regenerative burner unit 4 belonging to each zone 6 is performed for each zone 6 unit. That is, in this case, since the pilot 13 of each burner 7a, 7b is always in a combustion state, the burner combustion gas shut-off valves 17a, 17b are operated, and the switching valve 24 of each regenerative burner unit 4 is switched to burner combustion. When the supply destination burner of the gas 18 and the burner combustion air 21 is switched, the switching destination burners 7 a and 7 b are automatically ignited by the presence of the pilot 13, and the flame 12 is generated.
[0017]
As described above, the burner combustion control for each regenerative burner unit 4 is performed for each zone 6 of the heating furnace 3 because the heating temperature and the like may be different for each zone 6.
[0018]
[Problems to be solved by the invention]
However, the regenerative burner combustion control method for performing the combustion control on each regenerative burner unit 4 in the above-described procedure has the following problems to be solved.
[0019]
That is, for each zone 6 of the heating furnace 3, the ignition and extinguishing process for each regenerative burner machine 4 belonging to the zone 6 and the switching process of combustion and exhaust of each burner are sequentially performed. Then, the minimum burner combustion gas and the minimum burner combustion air are supplied in units of zone 6 until the ignition of all regenerative burner machines 4 belonging to zone 6 is completed. As a result, for the regenerative burner unit 4 ignited first, the minimum burner combustion gas and the minimum burner combustion air supplied to the corresponding zone 6 are supplied to one regenerative burner unit 4. .
[0020]
As a result, a strong wind caused by burner combustion gas or burner combustion air hits the pilot 13 during combustion, and the pilot 13 is misfired before the burners 7a and 7b are ignited or misfired by suction even after the burners 7a and 7b are ignited. Or Further, there is a concern that the pilot 13 of the burners 7a and 7b during the exhaust may be misfired due to the strong exhaust gas.
[0021]
The same applies to the regenerative burner 4 that is ignited for the second and third units. In this case, the burner combustion gas 18 and the burner combustion air 21 supplied to the regenerative burner machine 4 ignited by the second or third burner are the first burner combustion gas 18 and the burner combustion air 21 described above. However, the wind pressure is still small enough to cause the burning pilot 13 to misfire sufficiently.
[0022]
When the pilot 13 misfires, there is a problem in that the burners 7a and 7b can only ignite and exhaust unburned gas. Furthermore, when the pilot 13 of the burners during exhaust 7a, 7b misfires, there is a problem that the combustion of the burners of the regenerative burner machine 4 and the switching of exhaust do not proceed smoothly.
[0023]
If the position near the exhaust burners 7a, 7b of the regenerative burner unit 4 in the radiant tube 5 is heated to a high temperature by the exhaust gas of the flame 12 of the burning burners 7a, 7b, the exhaust burner 7a, Even when the pilot 13 of 7b is not burning, the burner may be automatically ignited when the burner combustion gas 18 and the burner combustion air 21 are supplied.
[0024]
However, depending on the zone 6 of the heating furnace 3, the heating temperature may be set low. In such a case, since the temperature of the exhaust gas is low, the position of the radiant tube 5 near the burners 7a and 7b during the exhaust of the regenerative burner machine 4 remains in a low temperature state. In such a state, if the pilot 13 of the exhausting burners 7a, 7b misfires for the above-described reason, the burners 7a, 7b to be switched to are ignited when the burners 7a, 7b of the regenerative burner machine 4 are switched between combustion and exhaust. No, or there is a problem that requires a long time for ignition.
[0025]
The present invention has been made in view of such circumstances, and by adjusting the ignition timing and the amount of burner combustion gas and burner combustion air for each regenerative burner machine included in each zone of the heating furnace, each zone is controlled. The ignition and extinguishing of each regenerative burner belonging to the group, the burner combustion, and the switching of exhaust can be reliably ignited for each burner, and the safety and temperature control accuracy of the heating furnace in which each regenerative burner is incorporated It is an object of the present invention to provide a regenerative burner combustion control method that can be significantly improved.
[0026]
[Means for Solving the Problems]
The present invention attaches a plurality of radiant tube type regenerative burners to each zone of the heating furnace, and applies a pair of regenerative burners belonging to each zone to the burner combustion gas supplied in each zone unit. The present invention is applied to a regenerative burner combustion control method in which a heating furnace is heated alternately by a burner through a radiant tube, and the exhaust gas after heating is stored in a storage zone of a burner that is not burning among a pair of burners.
[0027]
In order to solve the above problems, in the regenerative burner combustion control method of the present invention, when igniting each regenerative burner belonging to each zone, a pilot combustion gas is supplied to each regenerative burner. The pilot is ignited, and burner combustion gas is supplied to each regenerative burner machine by a predetermined amount of the pilot combustion gas so that all regenerative burner machines belonging to the corresponding zone are ignited simultaneously.
[0028]
In the regenerative burner combustion control method configured as described above, when igniting each regenerative burner unit belonging to each zone, all regenerative burner units belonging to the corresponding zone are simultaneously ignited. As described above, simultaneously igniting all regenerative burner machines, since the burner combustion gas supplied in each zone unit is equally supplied to the burners of all regenerative burner machines, a specific regenerative burner machine is used. Since a large amount of burner combustion gas is not supplied to the burner, the misfire of the pilot due to strong wind can be prevented.
[0029]
Further, another invention is the regenerative burner combustion control method of the above-described invention, in which the burner of each regenerative burner machine belonging to each zone is switched between burning and exhausting, the temperature of the zone or the radiant tube temperature in the heating furnace. From, it is determined whether or not the temperature in the radiant tube is a temperature that requires pilot combustion for ignition of the exhaust burner that is not burning in each regenerative burner machine, and the temperature in the radiant tube requires pilot combustion. When the temperature is high, pilot ignition is performed, pilot combustion is confirmed, and the burner combustion gas and air supply destination is switched from the burning burner to the exhausting burner, so that the corresponding exhausting burner is ignited and the burning burner is turned on. extinguish a fire.
[0030]
Further, another invention ignites the corresponding exhaust burner by switching the supply destination of the burner combustion gas and air from the burning burner to the exhausting burner when the temperature in the radiant tube does not require pilot combustion. And extinguishes the burner during combustion.
[0031]
As described above, it is determined whether the temperature in the radiant tube is a temperature that requires pilot combustion from the temperature of the corresponding zone or the radiant tube temperature in the heating furnace, and only when necessary, the pilot combustion is confirmed. To ignite the burner. Therefore, even if the heating temperature in the zone of the heating furnace is set low, it is possible to reliably switch the combustion and exhaust of the burner of the regenerative burner machine.
[0032]
Further, another invention is such that, when igniting each regenerative burner belonging to each zone, burner combustion gas and air that are four times or less the pilot combustion gas and air are supplied to each regenerative burner. I have.
[0033]
As described above, when the burner is ignited, the burning pilot is blown out by the burner combustion gas by supplying the burner combustion gas and the air that are four times or less the pilot combustion gas and the air to each regenerative burner machine. It was confirmed experimentally that this was prevented.
[0034]
Further, in another invention, the timing of switching between combustion and exhaust of the burner of each regenerative burner belonging to each zone is shifted for each regenerative burner.
[0035]
In this way, by shifting the timing of switching between combustion and exhaust of the burner of each regenerative burner machine for each regenerative burner machine, the combustion and exhaust of the burner of each regenerative burner machine belonging to each zone are switched at the same timing. Compared to the case, fluctuations in the combustion amount and the exhaust gas pressure in each burner of each regenerative burner machine can be suppressed to a minimum.
[0036]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing a configuration of a main part of a regenerative burner combustion control system to which a regenerative burner combustion control method according to an embodiment is applied. FIG. 2 is a schematic cross-sectional view showing a state in which a regenerative burner per zone is attached to a heating furnace. 11 and FIG. 12 are denoted by the same reference numerals, and detailed description of overlapping portions will be omitted. Specifically, the heating furnace 3, the conveyance path of the steel sheet 1 conveyed in the heating furnace 3, the arrangement of each regenerative burner machine 4 and the radiant tube 5 attached to each side wall 3a of the heating furnace 3, and The arrangement of each zone 6 is the same as in FIG. Therefore, FIG. 1 is a diagram extracting and showing main parts of the regenerative burner combustion control system shown in FIG. In FIG. 1, only the regenerative burner machine 4 and the radiant tube 5 provided on one side wall 3a of the heating furnace 3 are shown for simplification of the description.
[0037]
In each zone 6 of the heating furnace 3 to which the regenerative burner combustion control system of this embodiment is applied, a thermometer 30 for detecting the temperature in the heating furnace 3 is attached. The configuration of each regenerative burner unit 4 attached to each zone 6 of the heating furnace 3 is almost the same as the conventional regenerative burner unit 4 shown in FIG.
[0038]
In this embodiment system, a combustion gas source 31, a burner combustion air source 32, a pilot combustion air source 33, a shutoff valve drive unit 34, a switching valve drive unit 35, a burner combustion control unit 36, and an operation unit 37 are provided. .
[0039]
The combustion gas source 31 supplies the burner combustion gas 18 and the pilot combustion gas 16 to each regenerative burner machine 4 in each zone 6. The burner combustion air source 32 supplies the burner combustion air 21 to each regenerative burner machine 4 in each zone 6 in the same manner as the combustion gas source 31. Further, the pilot combustion air source 33 supplies the pilot combustion air 15 to each regenerative burner machine 4.
[0040]
The shut-off valve drive unit 34 controls the opening and closing of each shut-off valve based on an instruction from the burner combustion control unit 36. Further, the shut-off valve drive unit 34 adjusts the opening of each flow control valve based on an instruction from the burner combustion control unit 36. In addition, the switching valve driving unit 35 controls the switching of the switching valve 24 of each regenerative burner unit 4 based on the instruction of the burner combustion control unit 36. For example, the burner combustion control unit 36 formed by a computer or the like, ignites and extinguishes each regenerative burner machine 4 in each zone 6 and burns and exhausts the burners 7a and 7b in accordance with an operator's instruction via the operation unit 27. Perform switching control.
[0041]
2, a combustion gas supplied from a combustion gas source 31 is supplied to each regenerative burner machine 4 as a burner combustion gas 18 via a zone burner combustion gas flow regulating valve 38 and a zone burner combustion gas shutoff valve 39. The zone burner combustion gas flow regulating valve 38 regulates the flow rate of the burner combustion gas 18 supplied to the zone 6. That is, the burner combustion gas 18 having a flow rate corresponding to the set temperature in the heating furnace 3 of the zone 6 is supplied for each zone 6. As a result, the amount of burner combustion gas 18 controlled by the number of regenerative burners 4 installed is supplied to each regenerative burner 4 belonging to each zone 6. Further, the combustion gas supplied from the combustion gas source 31 is supplied directly to each regenerative burner 4 as the pilot combustion gas 16.
[0042]
The burner combustion air 21 supplied from the burner combustion air source 32 is adjusted to a flow rate corresponding to the zone 6 by a zone burner combustion air flow regulating valve 40 and supplied to each regenerative burner machine 4. The pilot combustion air 15 supplied from the pilot combustion air source 33 is supplied directly to each regenerative burner unit 4.
[0043]
The burner combustion control unit 36 in the regenerative burner combustion control system having such a configuration performs combustion control on each regenerative burner unit 4 in each zone 6 of the heating furnace 3 according to the flowchart of FIG.
[0044]
When the operator inputs an operation start command for the entire system with the operation unit 37, the ignition and combustion / exhaust switching processing of the pilot 13 is performed (P1). Next, the ignition process of the burners 7a and 7b is performed (P2). After that, if an operation end command is not input (P3), if a certain period of time, such as 60 seconds, corresponding to the switching cycle of burner combustion / exhaust elapses (P4), heating is performed by the thermometer 30 attached to each zone 6. The furnace temperature of the furnace 3 is detected, and the temperature in the vicinity of the exhausting burners 7a and 7b in the radiant tube 5 in the corresponding zone 6 is estimated from the furnace temperature. It is determined whether or not the temperature is such that the ignition of the pilots 13a and 7b requires the combustion of the pilot 13 (P5).
[0045]
In the case of a low temperature that requires the combustion of the pilot 13, after confirming the combustion of the pilot 13, a process of switching the combustion / exhaust of the burners 7 a and 7 b (a pilot combustion burner switching process) is performed (P 6). If the combustion is at a high temperature that does not require the combustion of the pilot 13, a process of automatically switching the combustion / exhaust of the burners 7a and 7b without confirming the combustion of the pilot 13 (automatic combustion burner switching process) is performed (P7). .
[0046]
Then, when the operation end command is input in P3, the fire extinguishing process of each regenerative burner unit 4 is performed (P8).
[0047]
Next, the detailed operation of each process will be described in order using each flowchart.
FIGS. 4, 5, and 6 are flowcharts showing the detailed operation of the pilot ignition and the combustion / exhaust processing of P1. The pilot combustion air 15 is supplied from the pilot combustion air source 33 to each regenerative burner unit 4 (S1). The fuel gas source 31 is started (S2). In this state, when the operator turns on the pilot ignition switch of the operation unit 37 (S3), each regenerative burner unit 4 is assigned to each regenerative burner unit 4 belonging to this block 6 in a preset combustion / exhaust switching order. Is started (S4).
[0048]
First, the switching valve 24 is switched to the burner to be burned (S5, S6). The ignitions 11a and 11b of the combustion side burners 7a and 7b are energized (ON) (S7). In this state, the pilot combustion gas valves 20a, 20b of the combustion side burners 7a, 7b are opened (S8).
[0049]
Then, in S9, when the combustion of the pilot 13 is confirmed by the flame detection function of the ignitions 11a, 11b, the corresponding ignitions 11a, 11b are shut off (OFF) (S10). In this state, the pilot 13 of the burner to be burned is burning (S11). In S9 and S12, if the combustion of the pilot 13 cannot be confirmed for a certain period of time, it is determined that the pilot is not ignited or misfired, the pilot combustion gas valves 20a and 20b of the combustion side burners 7a and 7b are closed, and the corresponding ignition 11a , 11b are turned off (S13).
[0050]
If the ignition processing of the pilots 13 of the burners 7a and 7b of all the regenerative burner units 4 belonging to the zone 6 is not completed (S14), then in S15, the next regenerative burner unit 4 is activated. The ignition process for the pilot 13 is started (S15).
[0051]
In S14, when the ignition processing of the pilots 13 of the burners 7a, 7b on the combustion scheduled side of all the regenerative burners 4 belonging to the zone 6 is completed, all the regenerative burners belonging to the zone 6 are changed from S16. In accordance with the switching timing of the combustion / exhaust of the burners 7a and 7b of the machine 4, that is, at the timing when the burners 7a and 7b to be exhausted are switched to the burners 7a and 7b to be burned, the combustion is newly changed to the scheduled burning. The ignition process of the pilot 13 of the burners 7a and 7b of each regenerative burner unit 4 is performed.
[0052]
Note that the timing of switching the combustion and exhaust of the burners 7a and 7b of each regenerative burner unit 4 belonging to one zone 6 at a cycle of 30 seconds is shifted every predetermined time for each regenerative burner unit 4.
[0053]
Then, when the burner 7a, 7b of one regenerative burner unit 4 belonging to the relevant zone 6 comes to the timing of switching between combustion and exhaust and the switching valve 24 starts switching (S17), both of the regenerative burner units 4 The pilot combustion gas shutoff valves 20a and 20b are closed, and the pilots 13 of both burners 7a and 7b are once extinguished (S18). When the switching of the switching valve 24 is completed (S19), the ignitions 11a and 11b of the burners 7a and 7b which are newly on the combustion side this time are energized (ON) (S20). In this state, the pilot combustion gas valves 20a, 20b of the burners 7a, 7b on the combustion side are opened (S21).
[0054]
Then, in S22, when the combustion of the pilot 13 is confirmed by the flame detection function of the ignitions 11a, 11b, the corresponding ignitions 11a, 11b are shut off (OFF) (S23). In this state, the pilot 13 to be burned is burning (S24). In S22 and S25, if the combustion of the pilot 13 cannot be confirmed for a certain period of time, it is determined that the pilot is not ignited or misfired, the pilot combustion gas valves 20a and 20b of the combustion side burners 7a and 7b are closed, and the corresponding ignition 11a , 11b are turned off (S26).
[0055]
If the ignition processing of the pilots 13 of the newly scheduled burners 7a and 7b of all the regenerative burners 4 belonging to the zone 6 is not completed (S27), the next regenerative burner is determined in S28. The ignition process for the pilot 13 of the machine 4 is started.
[0056]
In S27, when the ignition processing of the pilots 13 of the burners 7a and 7b scheduled to burn in all the regenerative burners 4 belonging to the zone 6 is completed, the current pilot ignition and combustion / exhaust switching processing is completed.
[0057]
In such an ignition system of the pilot 13, the pilot 13 of the burners 7 a and 7 b scheduled to burn in each regenerative burner unit 4 belonging to the zone 6 is ignited, while the pilot 13 of the burners 7 a and 7 b scheduled to be exhausted is Not ignited. This is because the pilot 13 of the exhausting burners 7a and 7b is easily misfired by the exhaust gas.
[0058]
Next, the detailed operation of the burner ignition process at P2 in FIG. 3 will be described with reference to FIG.
When the operator presses the burner ignition switch of the operation unit 37 (Q1), the ignition processing of each regenerative burner unit 4 belonging to the zone 6 designated for operation is started (Q2). Then, the burner combustion gas shutoff valves 17a, 17b of the burners 7a, 7b scheduled to burn specified by the switching valves 24 in all the regenerative burner machines 4 belonging to the zone 6 are opened (Q3). Next, the flow rate of the burner combustion air 21 supplied to each regenerative burner machine 4 at the zone burner combustion air flow regulating valve 40 of the corresponding zone 6 is, for example, three times or more and four times or less the flow rate of the pilot combustion air 15. (Q4).
[0059]
Next, the zone burner combustion gas shutoff valve 39 of the corresponding zone 6 is opened (Q5). Further, the flow rate of the burner combustion gas 18 supplied to each regenerative burner machine 4 is set to, for example, three times or more and four times or less the flow rate of the pilot combustion gas 16 by the zone burner combustion gas flow regulating valve 38 of the corresponding zone 6. Adjust (Q6).
[0060]
In this state, the burner combustion gas 18 and the burner combustion air 21 are supplied to the burners 7a and 7b scheduled to be burned specified by the switching valves 24 in all the regenerative burner machines 4 belonging to the corresponding zone 6, so that the combustion is started. By the pilot 13, the burners 7a and 7b to be burned are ignited, and a flame 12 is generated.
[0061]
In the method of igniting the burners 7a and 7b of the regenerative burner unit 4 as described above, when igniting each regenerative burner unit 4 belonging to each zone 6, all the regenerative burner units 4 belonging to the zone 6 are ignited. The combustion-side burners 7a and 7b are simultaneously ignited. As described above, simultaneously igniting the burners 7a and 7b of all the regenerative burner units 4 allows the burner combustion gas supplied in each zone unit to be evenly distributed to the combustion side burners 7a and 7b of all the regenerative burner units 4. Therefore, a large amount of burner combustion gas 18 and a large amount of burner combustion air 21 are not supplied to the burners 7a and 7b of the specific regenerative burner machine 4. It can be prevented from occurring.
[0062]
Further, at the time of ignition of the burner, the burning pilot is supplied with burner combustion gas 18 and burner combustion air 21 which are three times or more and four times or less than the pilot combustion gas 16 to each regenerative burner machine 4 so that the burning pilot can burn the burner. Blowing out by the gas 18 and the burner combustion air 21 is reliably prevented.
[0063]
Next, the detailed operation of the pilot combustion burner switching process at P6 in FIG. 3 will be described with reference to FIGS.
When the combustion / exhaust switching timing of the burners 7a and 7b of the regenerative burner unit 4 comes and the switching valve 24 starts switching (R1), both the pilot combustion gas shut-off valves 20a and 20b of the regenerative burner unit 4 are started. , And the burner combustion gas shutoff valves 17a, 17b are closed, and both the burners 7a, 7b and both the pilots 13 are once extinguished (R2). When the switching of the switching valve 24 is completed (R3), the ignitions 11a and 11b of the burners 7a and 7b which are newly on the combustion side this time are energized (ON) (R4). In this state, the pilot combustion gas valves 20a and 20b of the combustion side burners 7a and 7b are opened (R5).
[0064]
Then, in R6, when the combustion of the pilot 13 is confirmed by the flame detection function of the ignitions 11a and 11b, the corresponding ignitions 11a and 11b are shut off (OFF) (R7). In this state, since the pilot 13 of the combustion side burners 7a and 7b is burning, the burner combustion gas valves 17a and 17b of the combustion side burners 7a and 7b are opened (R8). Therefore, the combustion side burners 7a and 7b are ignited, and a flame 12 is generated.
[0065]
In R6 and R9, if the combustion of the pilot 13 cannot be confirmed for a certain period of time, it is determined that the pilot has not ignited or misfired, and the pilot combustion gas valves 20a and 20b of the combustion side burners 7a and 7b are closed and the corresponding ignition is performed. 11a and 11b are cut off (OFF) (R10). Therefore, the combustion side burners 7a and 7b do not ignite.
[0066]
When the combustion / exhaust switching process for the burners 7a and 7b of the regenerative burner unit 4 is completed, the regenerative burner unit 4 for which the combustion / exhaust switching process is to be executed next is selected (R11), and FIG. Return to P3.
[0067]
Next, the detailed operation of the automatic combustion pilot combustion burner switching process at P7 in FIG. 3 will be described with reference to FIG.
When the combustion / exhaust switching timing of the burners 7a and 7b of the regenerative burner unit 4 comes and the switching valve 24 starts switching (U1), both pilot combustion gas shutoff valves 20a and 20b of the regenerative burner unit 4 are used. And both the burner combustion gas shut-off valves 17a, 17b are closed, and both the burners 7a, 7b and both pilots 13 are extinguished (U2). When the switching of the switching valve 24 is completed (U3), the burner combustion gas shut-off valves 17a and 17b of the burners 7a and 7b which are newly on the combustion side this time are opened (U4). Since the temperature in the vicinity of the burners 7a and 7b which have newly become the combustion side in the radiant tube 5 this time is sufficiently high, even if the pilot 13 is not burning, the corresponding burners 7a and 7b automatically ignite and the flame 12 results.
[0068]
When the combustion / exhaust switching process of the burners 7a and 7b of the regenerative burner unit 4 is completed, the regenerative burner unit 4 for which the combustion / exhaust switching process is next executed is selected (U5), and FIG. Return to P3.
[0069]
As described above, the position near the burner 7a (7b) on the exhaust side of the regenerative burner machine 4 in the radiant tube 5 is kept warm by the exhaust gas of the flame 12 output from the burner 7b (7a) on the combustion side to the heating furnace 3. Therefore, the temperature near the burner 7a (7b) on the exhaust side of the regenerative burner machine 4 in the radiant tube 5 is set to a temperature corresponding to the temperature measured by the thermometer 30 in each zone 6 in the heating furnace 3. Become.
[0070]
Therefore, when switching the combustion / exhaust of the burners 7 a and 7 b of each regenerative burner unit 4 belonging to each zone 6, the temperature in the radiant tube 5 is changed from the temperature of the corresponding zone 6 in the heating furnace 3 to the burner 7 a. , 7b to determine whether the temperature is such that the pilot 13 needs to be ignited, and only when necessary, confirms the combustion of the pilot 13 and ignites the corresponding burners 7a, 7b. I have.
[0071]
Therefore, even if the heating temperature in the zone 6 of the heating furnace 3 is set to be low, the combustion / exhaust of the burners 7a and 7b of the regenerative burner machine 4 can be reliably switched.
[0072]
If the combustion of the pilot 13 is not necessary for the ignition of the burner, the ignition of the pilot 13 is not performed from the beginning, and the combustion of the regenerative burner 4 Since the combustion / exhaust switching of the burners 7a and 7b can be performed, the processing load on the burner combustion control unit 36 can be reduced, and the usage amount of the pilot combustion gas 16 can be reduced.
[0073]
Furthermore, since the pilots 13 of the exhaust burners 7a and 7b, which are not burning, of the regenerative burners 4 are always extinguished, the amount of the pilot combustion gas 16 used can be reduced, and the pilot 13 misfires during the combustion. And no unburned gas of the pilot combustion gas 16 is generated.
[0074]
Also, by switching the switching valve 24 between the burners 7a and 7b of each regenerative burner unit 4 belonging to one zone 6, for example, the switching timing is changed every 30 seconds. Staggered every hour. Therefore, the change of the combustion amount and the exhaust gas in each regenerative burner machine 4 caused by the change of the flow direction of the burner combustion gas 21 by switching the switching valve 24 is prevented from being concentrated at the same timing. As a result, the control accuracy of the entire regenerative burner combustion control system can be further improved.
[0075]
【The invention's effect】
As described above, in the regenerative burner combustion control method of the present invention, all regenerative burner machines belonging to each zone are ignited simultaneously. Therefore, since a large amount of burner combustion gas is not supplied to the burner of a specific regenerative burner machine, it is possible to prevent the pilot from misfiring due to strong wind.
[0076]
Also, it is determined whether or not the temperature of the radiant tube is a temperature at which pilot combustion is required for ignition of the burner, and if necessary, the combustion of the pilot is confirmed and ignition of the corresponding burner is performed. ing. Therefore, even if the heating temperature in the zone of the heating furnace is set low, it is possible to reliably switch the combustion and exhaust of the burner of the regenerative burner machine.
[0077]
Therefore, the safety and temperature control accuracy of the heating furnace in which each regenerative burner is incorporated can be greatly improved.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a schematic configuration of a regenerative burner combustion control system to which a regenerative burner combustion control method according to an embodiment of the present invention is applied;
FIG. 2 is a schematic sectional view showing a schematic configuration of a regenerative burner machine incorporated in the system of the embodiment.
FIG. 3 is a flowchart showing an overall processing operation executed by a burner combustion control unit incorporated in the system of the embodiment;
FIG. 4 is a flowchart showing a detailed operation of pilot ignition and combustion / exhaust switching processing executed by the burner combustion control unit.
FIG. 5 is a flowchart showing a detailed operation of a pilot ignition and combustion / exhaust switching process also performed by the burner combustion control unit.
FIG. 6 is a flowchart showing the detailed operation of pilot ignition and combustion / exhaust switching processing also performed by the burner combustion control unit.
FIG. 7 is a flowchart showing a detailed operation of a burner ignition process executed by the burner combustion control unit;
FIG. 8 is a flowchart showing a detailed operation of a pilot combustion burner switching process executed by the burner combustion control unit.
FIG. 9 is a flowchart showing a detailed operation of a pilot combustion burner switching process also performed by the burner combustion control unit.
FIG. 10 is a flowchart showing a detailed operation of an automatic combustion burner switching process executed by the burner combustion control unit.
FIG. 11 is a diagram showing a heating furnace equipped with a general regenerative burner machine.
FIG. 12 is a schematic sectional view showing a schematic configuration of a general regenerative burner machine.
[Explanation of symbols]
1 ... steel plate
3. Heating furnace
4 ... Regenerative burner machine
5 ... Radiant tube
6… Zone
7a, 7b ... burner
11a, 11b ... ignition
12 ... Fire
13 ... Pilot
15 ... Pilot combustion air
16 ... Pilot combustion gas
17a, 17b ... burner combustion gas shutoff valve
20a, 20b ... pilot combustion gas shutoff valve
18 Burner combustion gas
21 Burner combustion air
24 ... Switching valve
30 ... thermometer
31 ... Combustion gas source
32 burner combustion air source
33 ... Pilot combustion air source
36: Burner combustion control unit

Claims (5)

A plurality of radiant tube type regenerative burners are attached to each zone of the heating furnace, and the burner combustion gas supplied in each zone unit is alternately turned on and off by a pair of burners of each regenerative burner belonging to each zone. In the regenerative burner combustion control method for burning and heating the heating furnace through the radiant tube, and storing heat in the storage zone of the burner that is not burning out of the pair of burners with the heated exhaust gas,
When igniting each regenerative burner belonging to each zone,
A pilot combustion gas is supplied to each of the regenerative burners to ignite the pilot,
A method of controlling combustion of a regenerative burner, comprising supplying a burner combustion gas having a predetermined multiple of the pilot combustion gas to each of the regenerative burner units and simultaneously igniting all regenerative burner units belonging to a corresponding zone. When switching the burner combustion and exhaust of each regenerative burner belonging to each zone,
From the temperature of the corresponding zone or the radiant tube temperature in the heating furnace, it is determined whether or not the temperature in the radiant tube is a temperature that requires pilot combustion for ignition of the exhaust burner that is not burning each regenerative burner machine. ,
When the temperature in the radiant tube is a temperature that requires pilot combustion, perform pilot ignition and confirm pilot combustion,
2. A regenerative burner combustion control according to claim 1, wherein the supply destination of the burner combustion gas and air is switched from the burning burner to the exhausting burner to ignite the corresponding exhausting burner and extinguish the burning burner. Method. When the temperature in the radiant tube does not require pilot combustion, by switching the supply destination of the burner combustion gas and air from the burning burner to the exhausting burner, the corresponding exhausting burner is ignited, and the burning burner is turned on. 3. The method according to claim 2, wherein the fire is extinguished. When igniting each regenerative burner unit belonging to each zone, the regenerative burner unit is supplied with burner combustion gas and air that are four times or less the pilot combustion gas and air. The method of controlling combustion of a regenerative burner according to any one of claims 1 to 3. The regenerative burner combustion control according to any one of claims 1 to 4, wherein the timing of switching between combustion and exhaust of the burner of each regenerative burner belonging to each zone is shifted for each regenerative burner. Method.

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