JP5404533B2 - Combustion control method of heat storage combustion type heat treatment furnace - Google Patents

Description

  The present invention relates to a burner section provided with a fuel gas supply pipe, a heat storage chamber containing a heat storage material, an air supply pipe for supplying combustion air to the heat storage chamber, and an exhaust gas discharge pipe for discharging combustion exhaust gas from the heat storage chamber And at least one pair of regenerative burners, wherein one of the regenerative burners guides combustion air from the air supply pipe through the heat storage chamber to the burner section and injects fuel gas from the fuel gas supply pipe in the burner section. On the other hand, in the other regenerative burner, the regenerative burner conducts a regenerative operation in which the flue gas is guided to the heat storage chamber and the heat of the flue gas is stored in the heat storage material and discharged from the exhaust gas discharge pipe. The present invention relates to a combustion control method for a heat storage combustion heat treatment furnace in which the above-described combustion operation and heat storage operation in a heat storage burner are alternately switched. In particular, in a regenerative combustion heat treatment furnace in which a fuel gas is supplied from a fuel gas supply device that supplies a certain amount of fuel gas to a fuel gas supply pipe in each regenerative burner, a combustion operation and a heat storage operation in a pair of regenerative burners are performed. In switching, when starting the combustion operation of the regenerative burner during the heat storage operation, it is characterized in that rapid combustion is suppressed.

  Conventionally, when heat treating a material to be treated, a burner unit provided with a fuel gas supply pipe, a heat storage chamber containing a heat storage material, an air supply pipe supplying combustion air to the heat storage chamber, and combustion from the heat storage chamber Using a regenerative combustion heat treatment furnace provided with at least a pair of regenerative burners having exhaust gas discharge pipes for discharging exhaust gas, and in one regenerative burner, the combustion air is led from the air supply pipe to the burner section through the regenerative chamber. At the same time, the combustion operation is performed by injecting fuel gas from the fuel gas supply pipe in the burner section, while in the other heat storage type burner, the combustion exhaust gas is guided to the heat storage chamber, and the heat of the combustion exhaust gas is stored in the heat storage material. Thus, a heat storage operation for discharging from the exhaust gas discharge pipe is performed, and the combustion operation and the heat storage operation in the pair of heat storage burners are alternately switched.

  Further, in the above heat storage combustion type heat treatment furnace, in order to continuously heat treat the material to be treated, a plurality of pairs of heat storage burners are provided in the heat treatment furnace, and in each pair of heat storage burners, combustion operation and heat storage operation are performed. What changed the timing which switches is also used.

  Further, in the above-mentioned heat storage combustion type heat treatment furnace, when supplying fuel gas to the fuel gas supply pipe in each of the above heat storage type burners, each fuel gas supply pipe is generally supplied from a fuel gas supply device that supplies a certain amount of fuel gas. It is performed to supply fuel gas.

  Here, in the heat storage combustion type heat treatment furnace as described above, when alternately switching between the combustion operation and the heat storage operation in the pair of heat storage type burners, conventionally, as shown in Patent Documents 1 and 2, during the combustion operation, In the regenerative burner, after stopping the supply of fuel gas in the fuel gas supply pipe, the supply of combustion air in the air supply pipe is stopped, while in the regenerative burner during the heat storage operation, for the combustion in the air supply pipe After starting the supply of air, the fuel gas supply pipe starts to supply the fuel gas to start combustion, and as shown in Patent Document 3, in a regenerative burner during a combustion operation At the same time as stopping the supply of fuel gas and combustion air, in the heat storage burner during the heat storage operation, start the supply of fuel gas and combustion air, Those so as to start the burn is known.

  Here, in the above-described Patent Documents 1 to 3, when the heat storage type burner in the heat storage operation starts combustion, in the heat storage type burner in the combustion operation, the combustion gas from the fuel gas supply device described above In the fuel gas supply pipe from the fuel gas supply device to the regenerative burner, the gas pressure of the fuel gas is higher than usual, and the regenerative burner during the heat storage operation is stopped. At the beginning of combustion, a larger amount of fuel gas is supplied from the fuel gas supply device and combustion starts.

  For this reason, in the case of those shown in these patent documents, rapid combustion is performed at the start of combustion in the heat storage burner during the above heat storage operation, and the pressure in the heat storage combustion heat treatment furnace changes greatly, or incomplete combustion occurs. As a result, there is a problem that proper combustion cannot be stably performed. In particular, when a non-combustible gas such as propane gas is used as the above fuel gas, black smoke (soot) is generated due to incomplete combustion, causing environmental problems and soot adhering to the material to be treated. As a result, there is a problem that heat treatment cannot be performed properly.

JP-A-10-185176 JP 11-159744 A Japanese Patent No. 3523903

  The present invention relates to a burner section provided with a fuel gas supply pipe, a heat storage chamber containing a heat storage material, an air supply pipe for supplying combustion air to the heat storage chamber, and an exhaust gas discharge pipe for discharging combustion exhaust gas from the heat storage chamber And at least one pair of regenerative burners, wherein one of the regenerative burners guides combustion air from the air supply pipe through the heat storage chamber to the burner section and injects fuel gas from the fuel gas supply pipe in the burner section. On the other hand, in the other regenerative burner, the regenerative burner conducts a regenerative operation in which the flue gas is guided to the heat storage chamber and the heat of the flue gas is stored in the heat storage material and discharged from the exhaust gas discharge pipe. It is also an object to solve the above problems in a heat storage combustion heat treatment furnace in which the above combustion operation and heat storage operation in the heat storage burner are alternately switched. It is.

  That is, in the present invention, in a regenerative combustion heat treatment furnace in which fuel gas is supplied from a fuel gas supply device that supplies a constant amount of fuel gas to a fuel gas supply pipe in each regenerative burner, a pair of regenerative burners When switching between the combustion operation and the heat storage operation in the above, it is characterized in that rapid combustion is suppressed when starting the combustion operation of the heat storage burner during the heat storage operation.

  In the present invention, in order to solve the problems as described above, a burner portion provided with a fuel gas supply pipe, a heat storage chamber containing a heat storage material, an air supply pipe for supplying combustion air to the heat storage chamber, At least a pair of regenerative burners having an exhaust gas discharge pipe for discharging combustion exhaust gas from the heat storage chamber is provided. In one heat storage burner, the combustion air is led from the air supply pipe through the heat storage chamber to the burner section. The fuel gas is injected from the fuel gas supply pipe in the section to perform the combustion operation, while in the other heat storage burner, the combustion exhaust gas is guided to the heat storage chamber, and the heat of the combustion exhaust gas is stored in the heat storage material, and the exhaust gas discharge pipe In a combustion control method for a heat storage combustion heat treatment furnace that performs a heat storage operation to be discharged from the combustion chamber and alternately switches between the combustion operation and the heat storage operation in the pair of heat storage burners. When fuel gas is supplied from the fuel gas supply device that supplies a certain amount of fuel gas to the fuel gas supply pipe in each of the heat storage type burners, and the combustion operation and the heat storage operation in the pair of heat storage type burners are switched, In the regenerative burner during the combustion operation, before reducing the supply of the fuel gas from the fuel gas supply tube and the supply of the combustion air from the air supply tube, the fuel gas supply tube in the regenerative burner during the heat storage operation Fuel gas and combustion air are supplied from the air supply pipe and combustion is started.

  When switching between the combustion operation and the heat storage operation in the pair of heat storage burners as described above, in the heat storage burner during the combustion operation, the fuel gas supply from the fuel gas supply pipe and the combustion air from the air supply pipe If the fuel gas and the combustion air are supplied from the fuel gas supply pipe and the air supply pipe in the heat storage burner during the heat storage operation before starting the combustion, Since the fuel gas is supplied from the fuel gas supply device that supplies the fuel gas to the heat storage burner that is in the combustion operation, the fuel gas supply to the heat storage burner is started. The amount of fuel gas supplied to the internal heat storage burner is reduced, and combustion is started with a small amount of fuel gas.

  Here, as the heat storage combustion type heat treatment furnace, a plurality of pairs of heat storage type burners may be provided, and in each pair of heat storage type burners, the timing for switching between the combustion operation and the heat storage operation may be different. it can.

  Further, in the combustion control method of the heat storage combustion type heat treatment furnace of the present invention, when switching between the combustion operation and the heat storage operation in the pair of heat storage burners, the fuel gas in the fuel gas supply pipe is switched in the heat storage burner during the combustion operation. After the supply and supply of combustion air in the air supply pipe are stopped, the combustion exhaust gas is discharged from the exhaust gas discharge pipe, and the combustion exhaust gas is discharged from the exhaust gas discharge pipe in the heat storage burner during the heat storage operation After the operation is stopped, it is preferable to start supply of fuel gas in the fuel gas supply pipe and supply of combustion air in the air supply pipe. In this way, when switching between the combustion operation and the heat storage operation, part of the combustion air guided from the air supply pipe to the heat storage chamber is bypassed without going to the heat storage chamber during the switching operation by the switching valve or the like. It is prevented from being discharged through the exhaust gas discharge pipe.

  In the combustion control method of the heat storage combustion heat treatment furnace according to the present invention, when switching between the combustion operation and the heat storage operation in the pair of heat storage burners as described above, in the heat storage burner during the combustion operation, from the fuel gas supply pipe Before reducing the supply of fuel gas and the supply of combustion air from the air supply pipe, supply fuel gas and combustion air from the fuel gas supply pipe and the air supply pipe in the regenerative burner during the heat storage operation. As a result, the pressure of the fuel gas in the fuel gas supply pipe for supplying the fuel gas from the fuel gas supply device to the heat storage burner decreases, and the heat storage burner during the heat storage operation as described above When fuel gas is supplied to start combustion, the amount of fuel gas supplied to the heat storage burner during the heat storage operation is reduced, and at the beginning of starting the combustion operation, The intense combustion occurs is suppressed.

  As a result, according to the combustion control method for a regenerative combustion heat treatment furnace according to the present invention, when switching between the combustion operation and the heat storage operation in a pair of regenerative burner, the pressure in the regenerative combustion heat treatment furnace changes greatly, The occurrence of complete combustion is suppressed, and appropriate combustion can be performed stably. In particular, even when propane gas or the like with poor flammability is used for the above fuel gas, black smoke (soot) is prevented from being generated, causing environmental problems and soot being attached to the material to be treated. There is nothing to do.

In the combustion control method of the regenerative combustion type heat treatment furnace according to one embodiment of the present invention, it is a schematic sectional view showing the internal state of the regenerative combustion type heat treatment furnace. In the same embodiment, it is a schematic plan view of said regenerative combustion heat treatment furnace. In the embodiment, it is the schematic explanatory drawing which showed the state which performs a combustion operation | movement with one heat storage type burner in a pair of heat storage type burners, and performs a heat storage operation | movement with the other heat storage type burner. In the embodiment, it is the time chart which showed the operation | movement which switches combustion operation | movement and heat storage operation | movement in each heat storage type burner in a pair of each heat storage type burner. In the embodiment, it is the time chart which showed the example of a change of the operation | movement which switches combustion operation | movement and heat storage operation in each heat storage type burner in a pair of heat storage type burner.

  Hereinafter, a combustion control method for a regenerative combustion heat treatment furnace according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. In addition, the combustion control method for the regenerative combustion heat treatment furnace according to the present invention is not particularly limited to the one shown in the following embodiment, and can be implemented with appropriate modifications within a range not changing the gist of the invention.

  Here, in this embodiment, as shown in FIG. 1, the workpiece 1 made of steel led from the inlet 11 of the regenerative combustion heat treatment furnace 10 into the regenerative combustion heat treatment furnace 10 is moved by the walking beam 2. The heat treatment material 10 is conveyed and heat-treated in the regenerative combustion heat treatment furnace 10, and the material 1 thus heat treated is taken out from the regenerative combustion heat treatment furnace 10 through the outlet 12 of the regenerative combustion heat treatment furnace 10.

  In this embodiment, as shown in FIG. 2, in the above-described heat storage combustion heat treatment furnace 10, the pair of heat storage burners 20 having the burner portion 21 and the heat storage chamber 22 are opposed to each other. 4 pairs of regenerative burners 20 are provided in the regenerative combustion heat treatment furnace 10 along the moving direction of the workpiece 1 and a burner section in each regenerative burner 20 from a fuel gas supply device 30 that supplies a certain amount of fuel gas. The fuel gas is supplied to 21.

  Here, in the pair of heat storage burners 20, as shown in FIG. 3, in one heat storage burner 20a, an air supply pipe 24a that supplies combustion air to the heat storage chamber 22a in which the heat storage material 23a is accommodated. Open the air supply valve 25a provided in the exhaust gas, close the gas discharge valve 27a provided in the exhaust gas discharge pipe 26a for discharging the combustion exhaust gas through the heat storage chamber 22a, and enter the heat storage chamber 22a through the air supply pipe 24a. The guided combustion air is heated by the heat storage material 23a accommodated in the heat storage chamber 22a.

  Then, the combustion air heated in this way is supplied to the burner portion 21a, and the gas supply valve 29a for introducing the fuel gas to the fuel gas supply pipe 28a provided at the center of the burner portion 21a is opened, and the above-mentioned The fuel gas supplied from the fuel gas supply device 30 is injected from the fuel gas supply pipe 28a, and the combustion operation for burning the fuel gas in the regenerative combustion heat treatment furnace 10 is performed.

  On the other hand, in the other regenerative burner 20b, the gas supply valve 29b for supplying the fuel gas to the fuel gas supply pipe 28b and the air supply valve 25b provided in the air supply pipe 24b are closed to prevent combustion. On the other hand, the gas discharge valve 27b provided in the exhaust gas discharge pipe 26b for discharging the combustion exhaust gas through the heat storage chamber 22b is opened.

  Then, the combustion exhaust gas after being burned in the heat storage combustion heat treatment furnace 10 as described above is led to the heat storage chamber 22b, and the heat storage material 23b accommodated in the heat storage chamber 22b is used to store the heat of the combustion exhaust gas, A heat storage operation for discharging the combustion exhaust gas to the outside through the exhaust gas exhaust pipe 26b is performed.

  In the pair of heat storage burners 20a and 20b, the combustion operation and the heat storage operation as described above are alternately switched.

  Also, in each pair of regenerative burners 20, as described above, in each pair of regenerative burners 20a and 20b, the combustion operation and the regenerative operation are alternately switched, and each pair of regenerative burners 20 In the type burner 20, the timing for switching between the combustion operation and the heat storage operation is made different.

  Next, an operation of switching between the combustion operation and the heat storage operation in each of the pair of heat storage burners 20a and 20b in each pair of the heat storage burners 20 will be described based on the time chart shown in FIG.

  Here, when switching between the combustion operation and the heat storage operation, in the heat storage burner 20a during the combustion operation, an operation of closing the air supply valve 25a and the gas supply valve 29a in an open state is started to supply air. The amount of combustion air supplied from the pipe 24a to the burner portion 21a through the heat storage chamber 22a is gradually reduced, and the amount of fuel gas injected from the fuel gas supply pipe 28a is gradually reduced.

  Then, when the air supply valve 25a and the gas supply valve 29a are closed and the combustion air and the fuel gas are not supplied and the combustion is stopped, the closed gas discharge valve 27a is opened, After the heat of the combustion exhaust gas guided to the heat storage chamber 22a is stored in the heat storage material 23a accommodated in the heat storage chamber 22a, the combustion exhaust gas is discharged to the outside through the exhaust gas discharge pipe 26a.

  On the other hand, in the heat storage burner 20b during the heat storage operation, the heat storage burner 20a in the combustion operation is opened before the operation for closing the air supply valve 25a and the gas supply valve 29a is started. After closing a certain gas discharge valve 27b and stopping the operation of discharging the combustion exhaust gas through the exhaust gas discharge pipe 26b, the operation of opening the air supply valve 25b and the gas supply valve 29b in the closed state is started. To do.

  In the heat storage burner 20a during the combustion operation, before the operation for closing the air supply valve 25a and the gas supply valve 29a is started, in the heat storage burner 20b during the heat storage operation, the air supply pipe 24b Then, combustion air is supplied to the burner portion 21b through the heat storage chamber 22b, and fuel gas is injected from the fuel gas supply pipe 28b to start combustion.

  As described above, before the operation of closing the air supply valve 25a and the gas supply valve 29a is started in the heat storage burner 20a during the combustion operation, the air supply pipe 24b in the heat storage burner 20b during the heat storage operation is started. When the combustion air is supplied from the fuel gas and the fuel gas is injected from the fuel gas supply pipe 28b, the fuel gas supply device 30 that supplies a certain amount of fuel gas supplies the regenerative burner 20a during the combustion operation. The fuel gas is supplied to the regenerative burner 20b during the heat accumulating operation in a state where the fuel gas is being supplied.

  In the regenerative combustion heat treatment furnace 10 provided with four pairs of regenerative burners 20 as in this embodiment, a certain amount of fuel gas supplied from the fuel gas supply device 30 is converted into four pairs of regenerative burners 20. Are distributed and supplied to the four heat storage burners 20a each performing the combustion operation in FIG. 2 and the heat storage burner 20b during the heat storage operation for starting the combustion, and the heat storage type during the heat storage operation for starting the combustion The amount of fuel gas supplied to the burner 20b is smaller than in the normal state.

  For this reason, when the regenerative burner 20b during the regenerative operation starts combustion, sudden combustion is suppressed, and the pressure in the regenerative combustion heat treatment furnace 10 changes greatly or is incomplete. Combustion is prevented from occurring, and appropriate combustion can be stably performed.

  And in each said pair of heat storage type burner 20, when switching a combustion operation and a heat storage operation, when the heat storage type burner 20b in a heat storage operation starts combustion, it is suppressed that rapid combustion arises, Appropriate combustion can be performed stably. In particular, even when propane gas with poor flammability is used as fuel gas, black smoke (soot) is generated due to incomplete combustion as in the past, causing environmental problems and No longer adheres.

  Further, in the regenerative burner 20a during the combustion operation as described above, when the air supply valve 25a and the gas supply valve 29a are closed and combustion air and fuel gas are not supplied and combustion is stopped, The gas discharge valve 27a in the closed state is opened, and in the heat storage burner 20b during the heat storage operation, after the gas discharge valve 27b in the open state is closed, the air supply in the closed state is supplied. When the valve 25b and the gas supply valve 29b are opened, a part of the combustion air led from the air supply pipes 24a and 24b to the heat storage chambers 22a and 22b is bypassed without going to the heat storage chambers 22a and 22b. Exhaust gas exhaust pipes 26a and 26b are prevented from being discharged.

  As a result, in this embodiment, the ratio of the combustion air supplied into the regenerative combustion heat treatment furnace 10 is reduced, and the fuel gas and the combustion air supplied into the regenerative combustion heat treatment furnace 10 are reduced. It is possible to prevent the fluctuation of the ratio of the fuel, and to perform more appropriate combustion stably.

  In the above embodiment, when the combustion operation and the heat storage operation in the pair of heat storage burners 20a and 20b are alternately switched, the air supply valve 25a and the gas supply valve 29a are used in the heat storage burner 20a during the combustion operation. Is closed and the gas discharge valve 27a in the closed state is opened at the time when combustion is stopped because combustion air and fuel gas are not supplied, but the present invention is not limited to this.

  For example, as shown in FIG. 5, before the operation of closing the air supply valve 25a and the gas supply valve 29a is started in the heat storage burner 20a during the combustion operation, the heat storage burner 20b during the heat storage operation is closed. The operation of opening the air supply valve 25b and the gas supply valve 29b in the heated state is started, and when the fuel gas can be ignited in the heat storage burner 20b and combustion can be started, the heat storage burner in the above combustion operation is started. The operation of closing the air supply valve 25a and the gas supply valve 29a at 20a can be started.

  By doing so, the heat storage operation during the heat storage operation is stopped before the combustion air and the fuel gas are not supplied from the air supply valve 25a and the gas supply valve 29a in the heat storage burner 20a during the combustion operation and the combustion is stopped. The fuel gas is ignited in the burner 20b and combustion is started, and the pressure in the regenerative combustion heat treatment furnace 10 is prevented from fluctuating at the time of switching between the combustion operation and the heat storage operation in the pair of heat storage burners 20a and 20b. Will be able to.

  Here, in the regenerative burner 20a during the above-described combustion operation, the timing for starting the operation of closing the air supply valve 25a and the gas supply valve 29a is appropriate for the fuel gas in the regenerative burner 20b during the heat storage operation. In order to enable ignition to start combustion, in the heat storage burner 20b during the heat storage operation, the flow rate Va of the combustion air supplied from the air supply valve 25b and the fuel supplied from the gas supply valve 29b When the gas flow rate Vf becomes equal to or higher than the turn-down limit value at which combustion is possible, the air supply valve 25a and the gas supply valve 29a are closed in the regenerative burner 20a during the combustion operation. Start the operation.

DESCRIPTION OF SYMBOLS 1 Material to be processed 2 Walking beam 10 Thermal storage combustion type heat treatment furnace 11 Inlet 12 Outlet 20, 20a, 20b Thermal storage burner 21, 21a, 21b Burner part 22, 22a, 22b Thermal storage chamber 23a, 23b Thermal storage material 24a, 24b Air supply pipe 25a, 25b Air supply valve 26a, 26b Exhaust gas discharge pipe 27a, 27b Gas discharge valve 28a, 28b Fuel gas supply pipe 29a, 29b Gas supply valve 30 Fuel gas supply device

Claims (3)

  At least a burner section provided with a fuel gas supply pipe, a heat storage chamber containing a heat storage material, an air supply pipe for supplying combustion air to the heat storage chamber, and an exhaust gas discharge pipe for discharging combustion exhaust gas from the heat storage chamber A pair of regenerative burners is provided, and in one regenerative burner, combustion air is guided from the air supply pipe through the heat storage chamber to the burner section, and fuel gas is injected from the fuel gas supply pipe in the burner section to perform combustion operation On the other hand, in the other regenerative burner, the combustion exhaust gas is led to the heat storage chamber, the heat of the combustion exhaust gas is stored in the heat storage material and discharged from the exhaust gas discharge pipe, and the heat storage operation is performed. In the combustion control method for a heat storage combustion heat treatment furnace in which the combustion operation and the heat storage operation are alternately switched, the fuel gas supply device that supplies a certain amount of fuel gas is used. When the fuel gas is supplied to the fuel gas supply pipe in each of the heat storage burners and the combustion operation and the heat storage operation in the pair of heat storage burners are switched, the fuel gas supply pipe in the heat storage burner during the combustion operation is switched from the fuel gas supply pipe. Before reducing the supply of fuel gas and the supply of combustion air from the air supply pipe, in the regenerative burner during the heat storage operation, the fuel gas and the combustion air are removed from the fuel gas supply pipe and the air supply pipe. A combustion control method for a regenerative combustion heat treatment furnace, characterized by supplying the fuel and starting combustion.   In the combustion control method of the heat storage combustion type heat treatment furnace according to claim 1, a plurality of pairs of heat storage burners are provided in the heat storage combustion type heat treatment furnace, and in each pair of heat storage burners, a combustion operation and a heat storage operation are performed. A combustion control method for a regenerative combustion heat treatment furnace, characterized in that the switching timing is different.   3. A combustion control method for a heat storage combustion heat treatment furnace according to claim 1 or 2, wherein the fuel gas supply pipe is connected to the heat storage burner during the combustion operation when switching between the combustion operation and the heat storage operation in the pair of heat storage burners. After stopping the supply of fuel gas from the air and the supply of combustion air from the air supply pipe, the combustion exhaust gas is discharged from the exhaust gas discharge pipe, and in the regenerative burner during the heat storage operation, combustion is performed from the exhaust gas discharge pipe Combustion control method for a regenerative heat treatment furnace characterized by starting the supply of fuel gas from the fuel gas supply pipe and the supply of combustion air in the air supply pipe after stopping the operation of discharging the exhaust gas .

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