JP3751732B2 - Combustion control method of regenerative burner in melting and holding furnace - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a combustion control method for a regenerative burner system in a melting and holding furnace that supplies combustion air to a burner through a heat storage body and discharges combustion gas from the burner. The present invention relates to a combustion control method for a regenerative burner that prevents clogging of a heat accumulator due to heat.
[0002]
[Prior art]
Recently, high heat exchange efficiency can be obtained as a combustion device for melting and holding furnaces, and generation of waste heat can be recovered using a heat storage body as a combustion system that suppresses significant NOx generation and is energy-saving. Many regenerative burner systems that preheat air have been adopted.
[0003]
In the regenerative burner system, at least a pair of burner devices in which a burner and a heat storage body are combined are arranged in a furnace, and when one burner is combusted, combustion air is supplied to the combustion burner via the heat storage body. In the other non-burning burner, heat is stored by sucking the exhaust gas in the furnace through the heat storage body and exchanging heat with the heat storage body. The combustion is alternately switched and burned as the combustion air is heated.
[0004]
The regenerator burner used in this regenerative burner system is stored in the heat storage chamber with a gap so as to have an appropriate pressure loss, and when the outside combustion air and the exhaust gas in the furnace pass through the gap. It hits the heat accumulator and effectively conveys the amount of heat of the high-temperature exhaust gas to the combustion air.
[0005]
This regenerative burner system is used as a combustion device for melting and holding furnaces.For example, when melting an aluminum ingot, when the ingot becomes molten metal, a flux is used to obtain a good quality slab and billet. It is added to separate impurities from molten aluminum.
[0006]
[Problems to be solved by the invention]
However, when flux is added to the molten metal, the powder of the flux is scattered and sucked from the non-burning burner side of the alternating burner, sucked into the heat storage chamber, adheres to the heat storage body, and clogging occurs in a short period of time. It was.
[0007]
When clogging occurs, the air flow path becomes narrow, it becomes difficult to circulate, pressure loss increases, burner combustion amount decreases and heat exchange deteriorates and the heat storage effect decreases, so take out the heat storage body and remove deposits Or, it must be replaced with a new one, and since the furnace was stopped each time, there was a problem that continuous operation was impossible and work efficiency was very poor.
[0008]
The present invention has been researched and developed to solve the above-mentioned problems, and during the flux treatment to the molten metal, the burner is completely burned to prevent the flux powder from entering the heat storage chamber, and the heat storage body is The present invention provides a combustion control method for a regenerative burner in a melting and holding furnace that eliminates clogging and has high work efficiency and operation efficiency.
[0009]
[Means for Solving the Problems]
As means for solving the above-mentioned problems and achieving the object, in the present invention, at least a pair of regenerative burners is disposed, the regenerative burners are alternately burned, and the combustion exhaust gas is stored on the non-combustion side. In the melting and holding furnace in which the molten material is melted by the regenerative burner device that discharges through the body and the combustion side burner is supplied by the combustion side burner through the heat storage body, at the time of residual powder influence of the flux treatment of the molten metal, Combustion of regenerative burner characterized in that switching from alternating combustion to all burner continuous combustion is possible, and after the flux treatment is completed, reheated all burner continuous combustion, holding 1/2 burner continuous combustion, or holding alternating combustion can be selected. A control method was developed and adopted.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Reference numeral 1 denotes a melting and holding furnace body, and two sets of regenerative burners 2, 2, which form a pair of front and rear and left and right walls on both sides in the length direction. , 3 and 3 are provided, and an exhaust gas control valve 4 is provided on the furnace ceiling surface.
[0011]
As shown in FIG. 3, the regenerative burners 2 and 3 are provided with a heat storage chamber 6 in which a heat storage body 5 such as an alumina ball is accommodated in a lower portion, and an outer diameter of the heat storage body 5 on a bottom surface thereof. A smaller wire mesh 7 is stretched. The heat storage chamber 6 is filled with a large number of heat storage bodies 5 such as alumina balls, and the respective heat storage bodies 5 such as alumina balls are in point contact.
[0012]
Reference numeral 8 denotes a heat storage body outlet opening at the lower end of one side surface of the heat storage chamber 6, and a lid 9 is fitted to the heat storage body outlet 8. A heat insulating material 10 is adhered to the inner surface side of the lid body 9, and a U-shaped handle 11 is attached to the outer surface side.
[0013]
12 is an inclined duct that combines the supply of external combustion air to the bottom surface of the heat storage chamber and the exhaust gas discharge in the furnace, and the bottom surface is formed on an inclined surface 12a inclined from one to the other. An opening 13 is provided at the lower end on one side, and an opening / closing lid 14 is attached to the opening 13.
[0014]
A melting cycle in the melting and holding furnace having the above configuration will be described with reference to the flowchart of FIG. The left side shows the normal combustion mode, and the right side shows the flux processing mode. First, in step S1, one of the front, rear, left and right burners 2, 3, 2, 3 is alternately burned to preheat the heat storage body 5, and it is measured in step S2 whether the preset temperature reaches 800 ° C. When the temperature reaches 800 ° C., the process proceeds to the next step S3. When the temperature does not reach 800 ° C., the process returns to step S1 to perform the regenerator preheating alternating combustion.
[0015]
In step S3, the burners 2, 3, 2, and 3 are burned alternately in the front, rear, left, and right directions, and alternating combustion is performed until the aluminum ingot is melted. It is visually confirmed in step S4 whether the aluminum ingot has been melted down. After confirming that the molten metal is completely formed, the process proceeds to step S5 or step S6. If the ingot lump remains, the process returns to step S3, and melting alternating combustion is performed again. The melting cycle so far is the same without any change in the normal combustion mode and the flux processing mode, and the melting cycle in the normal combustion mode and the flux processing mode is different from this point onward.
[0016]
That is, in the normal combustion mode, in step S5, one of the front, rear, left and right burners 2, 3, 2, and 3 performs alternating combustion held to adjust the molten metal temperature, and the molten metal is discharged to the casting machine to determine whether the combustion is finished. In step S11, if YES, the fuel supply is stopped in step S12 and the combustion is terminated. If NO, the melting alternating combustion in step S3 is performed.
[0017]
On the other hand, in the flux processing mode, when the aluminum ingot is completely melted, in order to improve the quality of the slab or billet when it is agglomerated, the flux processing is performed for 30 to 40 minutes in step S6. At that time, from the combustion of one burner 2 at the rear and one burner 3 at the front, as shown in FIG. 2A, both burners 2, 2 at the rear and both burners, as shown in FIG. 2B. All the burners 3 and 3 are switched to continuous combustion, and the exhaust gas is discharged from the exhaust gas control valve 4 to prevent the flux powder from entering the heat storage chamber 6 and to adhere to the heat storage body 5. And a flux process is complete | finished by step S7.
[0018]
When the flux process in step S7 is completed, the reheating of all the burners 2, 2, 3, and 3 in step S8 is repeated, or the 1/2 burner continuous combustion of only burner 2, 2, or 3, and 3 in step S9. Either holding or holding the alternating combustion of the burners 2, 2, 3, and 3 in step S10 is selected.
[0019]
That is, if it takes a long time for the flux treatment and the hot water temperature is equal to or lower than the tapping temperature, the re-heating of all burner continuous combustion in step S8 is selected, and if the hot water temperature keeps the tapping temperature, 1/2 burner continuous in step S9. If combustion is selected, and if there is no residual powder of flux, retention of alternating combustion in step S10 is selected.
[0020]
The temperature of the molten metal is adjusted by performing any one of the reheating of all burner continuous combustion in step S8, the 1/2 burner continuous combustion in step S9, and the alternating combustion holding in step S10, and the molten metal is discharged to the casting machine. In step S12, the fuel supply is stopped and the combustion ends. If the process cannot be completed in step S11, the melt alternate combustion (recharge) in step S3 is performed.
[0021]
In the above-described embodiment, two regenerative burners 2, 2, 3, and 3 are provided on the front, rear, left, and right sides of the side walls of the melting and holding furnace. However, the present invention is not limited to this. Instead, the arrangement position and the number of arrangements can be freely set.
[0022]
【The invention's effect】
As described above, the present invention is provided with at least a pair of regenerative burners, alternately burning the regenerative burners, and exhausting the combustion exhaust gas through the non-combustion side heat accumulator, In the melting and holding furnace where the molten material is melted by the heat storage burner device that supplies combustion air via the heat storage body with the burner on the side, switching from alternating combustion to all burner continuous combustion when the residual powder is affected by the flux treatment of the melt Since the regenerative burner combustion control method is characterized by being able to select any one of re-heated full burner continuous combustion, holding 1/2 burner continuous combustion, and holding alternating combustion after the processing is completed, The effect is exhibited.
[0023]
Intrusion of flux powder into the heat storage chamber during flux treatment is prevented and it does not adhere to the heat storage body, eliminating clogging, and the frequency of replacement of the heat storage body is greatly reduced, long-term stable operation and high regenerative burner Performance can be maintained, continuous operation is possible, and work efficiency and operation efficiency can be greatly improved.
[0024]
In addition, after finishing the flux treatment, any one of re-heated full burner continuous combustion, holding 1/2 burner continuous combustion, and holding alternating combustion can be selected. While being able to hold | maintain, efficient combustion can be performed and the energy saving effect is acquired.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an example of an embodiment of the present invention.
FIG. 2 is a simplified plan view showing alternating combustion and total combustion in a melting and holding furnace.
FIG. 3 is an enlarged longitudinal sectional view of a regenerative burner portion of the present invention.
FIG. 4 is a flow chart of the dissolution cycle of the present invention.
[Explanation of symbols]
1 Melting and holding furnace 2 Regenerative burner 3 Regenerative burner 5 Thermal storage

Claims (1)

At least a pair of regenerative burners are disposed, and the regenerative burners are alternately burned to discharge the combustion exhaust gas through the non-combustion side heat storage body, while combustion air is stored in the heat storage body by the combustion side burner. In a melting and holding furnace that melts the melted material with a regenerative burner device that is supplied via a gas, when the residual powder is affected by the flux treatment of the molten metal, the combustion is switched from alternating combustion to all burner continuous combustion. A combustion control method for a regenerative burner in a melting and holding furnace, wherein any one of burner continuous combustion, holding 1/2 burner continuous combustion, and holding alternating combustion can be selected.

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