JPH04157123A - Method for controlling combustion with burner in aluminum melting furnace - Google Patents

Abstract

PURPOSE:To improve responsiveness of heat efficiency and control by separately executing combustion with burners constituting the combustion and burners intermittently stopping the combustion at the time of controlling the combustion with plural burners. CONSTITUTION:For example, in the side wall 21 in a tilting type circular furnace body 11, a gas exhaust hole 4 and six pieces of the burners 51-56 are set as shown in the figure. For example, in the case of reducing the combustion as a whole from the level of 100% of combustion degree in the burner 51-56, opening degrees of valves 61-71 are reduced and the number of revolutions in a blower 81 is reduced so as to correspond to this and the combustion of burner 51 is stopped. Further, in the case of reducing the combustion as a whole, the combustion of burner 54 facing to the burner 51 is stopped as the same and the case burner 51. Successively, the burner 51 55 53 is stopped in order. By this method, convectional atmosphere with the combustion flame of burner is continues to form in the furnace and Al scrap and molten metal can be heated with the convection heat and the purpose can be achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a burner combustion control method in an aluminum melting furnace.

For melting aluminum ingots and aluminum scraps,
Also, aluminum melting furnaces are used for alloying and refining molten aluminum. There are various kinds of aluminum melting furnaces, such as a stationary type, a tilting type, a circular furnace, and a square furnace.

Incidentally, an aluminum melting furnace is equipped with a plurality of burners as a heating source on its side wall. The combustion of the burner needs to be controlled depending on the operating conditions.

The present invention relates to an improvement in a burner combustion control method in an aluminum melting furnace as described above.

<Prior art and its problems> Conventionally, as a burner combustion control method in an aluminum melting furnace, the burn-up of a plurality of burners installed on the side wall of the furnace is increased or decreased almost equally. Conventionally, in order to prevent the combustion flames of the burners from shorting to the exhaust ports provided in the side wall of the furnace, a plurality of burners are arranged so that the combustion flames of the burners are directed in the opposite direction of the exhaust ports provided in the side wall of the furnace. An aluminum melting furnace is used, and the overall combustion is controlled by increasing or decreasing the burn-up of the plurality of burners almost equally depending on the operating conditions.

However, in the burner combustion control method in such a conventional aluminum melting furnace, the aluminum melting furnace originally used mainly heats the furnace wall with the combustion flame of the burner, and the radiant heat from the heated furnace wall is used to burn aluminum sugerap and molten aluminum. Since the burner combustion control method is based on this method, there are problems in that the thermal efficiency is poor and the control response is slow.

<Problems to be Solved by the Invention, Means for Solving the Problems> The present invention provides an improved combustion control method for a burner in an aluminum melting furnace that solves the conventional problems such as sloping.

Therefore, the present invention is characterized in that when controlling the combustion of a plurality of burners installed on the side wall of an aluminum melting furnace, the combustion is performed separately into burners that continue combustion and burners that substantially thin out combustion. This invention relates to a burner combustion control method in an aluminum melting furnace.

<Operation> In the present invention, when controlling the combustion of a plurality of burners, rather than increasing or decreasing the burn-up of the plurality of burners almost uniformly, the burner that continues combustion and the burner that substantially thins out combustion are used. This will be done separately. For example, in an aluminum melting furnace equipped with a total of six burners, if you want to reduce the overall burnup to 50%, instead of reducing the burnup of each of the six burners to 50%, The combustion degree of the burner is maintained at 100%, and the combustion of the remaining three burners is stopped. According to the present invention, it is possible to heat aluminum scrap, molten aluminum, etc. with convection heat by using the convection atmosphere formed in the furnace by the combustion flame of the burner that continues to burn, resulting in high thermal efficiency and easy control. Fast response. When controlling the overall combustion by dividing the burner into a burner that continues combustion and a burner that substantially thins out combustion, the burner that continues combustion maintains its burnup at 60% or more, and the burner that substantially thins out combustion. It is preferable that the burn-up of the burner is maintained at 10 to 20%. This is to prepare for reliable re-ignition of the burner in which combustion is substantially reduced while effectively utilizing the convection heat as described above.

In order to make more effective use of convection heat as described above, an aluminum melting furnace has multiple burners whose combustion flames are directed diagonally toward the surface of the molten metal in the furnace and form a swirling flow within the furnace as a whole. It is preferable to use a burner which is arranged in the exhaust port, and it is preferable to use a burner in which one burner close to the exhaust port is arranged so that its combustion flame blocks the exhaust port. is even more preferable. The aluminum melting furnace used in the present invention is a stationary type, a tilting type, a circular furnace, or a rectangular furnace. This is particularly effective in the case of furnaces.

Hereinafter, the configuration of the present invention will be explained in more detail based on the drawings.

<Example> Fig. 1 is a vertical cross-sectional view schematically showing an aluminum melting furnace that can be used in the present invention, Fig. 2 is a cross-sectional view schematically showing the aluminum melting furnace, and Fig. 3 is a schematic cross-sectional view of the aluminum melting furnace. 1 is a system diagram schematically illustrating an embodiment of the invention in use; FIG. Here, a tilting circular furnace is used, which is equipped with a tilting means (for example, a cylinder mechanism), which is not shown, at the bottom of the furnace. A lid 21 that can be opened and closed is attached to the top surface of the cylindrical main body l1.

An operating port 31 and an exhaust port 41 are provided opposite to each other in the side wall 12 of the main body 11, and a door 32 that can be opened and closed is attached to the operating port 31. And a total of six burners 51 ~ on the side wall 12
56 is equipped.

The burners 51 to 56 have a cross section of the cylindrical side wall 12 of approximately 6
It is equipped at the dividing position, and a total of 5 of these
In the burners 51 to 55, the combustion flame is the molten metal surface M (
When melting aluminum ingots or aluminum scrap, the furnace is arranged so as to face the surface of the molten metal after melting these metals and to form a swirling flow in the furnace as a whole, and an exhaust port is installed on the upstream side of the swirling flow. Remaining 1 close to 41
The burner 56 is arranged so that its combustion flame is directed toward the molten metal surface M in the furnace and blocks the exhaust port 41.

In FIG. 2, the burner 51 installed on the cylindrical side wall 12 is arranged diagonally downward at an opening angle θ1 with respect to the straight line connecting its nozzle portion and the center point C of the molten metal surface M. The combustion flame of the burner 51 is directed toward a so-called tangential region 51a of a circle R having an imaginary center point C on the molten metal surface M. The burners 52 to 55 are also arranged in the same manner as the burner 51, and their combustion flames are directed toward so-called tangential regions 52a to 55a of the circle R, respectively. The burners 51 to 55 are arranged so that their combustion flames are directed obliquely toward the molten metal surface M and form a swirling flow as a whole. On the other hand, the burner 56 is arranged diagonally downward at an opening angle θ, which is slightly larger than the angle θ, and the combustion flame of the burner 56 is directed toward the middle of the outside of the circle R imaginary on the molten metal surface M. area 56
It is oriented toward a. The burner 56 has its combustion flame on the molten metal surface M
is directed obliquely and is arranged so as to block the exhaust port 41 to prevent the swirling flow from short-circuiting to the exhaust port 41.

In FIG. 3, nozzle mix type burners 51 to
On the upstream side of the system that supplies air to 56 are valves 61 to 66.
The upstream side of the system for supplying fuel gas to the burners 51 to 56 is connected to a fuel gas supply source 82 after collecting via valves 71 to 76, and the valves 61 to The opening degrees of 66, 71 to 76 are controlled by a signal from an arithmetic unit 83. For example, when reducing the overall combustion from a level where the burn-up degrees of burners 51 to 56 are all 100%,
First, the opening degree of the valves 61 and 71 is reduced, and the rotational speed of the blower 81 is reduced accordingly, thereby substantially thinning out the combustion of the burner 51. In order to further reduce the overall combustion, next, the combustion of the burner 54 opposite to the burner 51 is substantially thinned out in the same manner as the burner 51. Thereafter, combustion is substantially thinned out sequentially from burner 52 to burner 55 to burner 53. The remaining burners, which continue combustion without substantially culling combustion, continue to form a swirling flow within the furnace.

<Effects of the Invention> As is already clear, the present invention described above has the advantage that a convection atmosphere can be continuously formed in the furnace by the combustion flame of the burner, and aluminum scrap, molten aluminum, etc. can be heated by convection heat. , has the advantage of good thermal efficiency and quick control response.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view schematically showing an aluminum melting furnace that can be used in the present invention, FIG. 2 is a cross-sectional view schematically showing the aluminum melting furnace, and FIG. FIG. 1 is a system diagram schematically illustrating an embodiment of the present invention. +1...Main body, 12...Side wall 41...Exhaust port, 51-56...Burner 61-
66.71-76...Valve 81...Blower,
82...Fuel gas supply source 83...Calculating device flash...Molten metal surface Patent applicant Daido Steel Co., Ltd. Agent Patent attorney Hiroshi Iriyama Figure 1 Figure 3

Claims (1)

[Claims] 1. When controlling the combustion of a plurality of burners installed on the side wall of an aluminum melting furnace, the combustion is divided into burners that continue combustion and burners that substantially thin out combustion. A burner combustion control method in an aluminum melting furnace. 2. The burner in an aluminum melting furnace according to claim 1, wherein the burner that continues combustion maintains its burnup at 60% or more, and the burner that substantially thins out combustion maintains its burnup at 10 to 20%. combustion control method. 3. The aluminum melting furnace used is one in which a plurality of burners are arranged so that their combustion flames are directed obliquely to the surface of the molten metal in the furnace, and a swirling flow is formed in the furnace as a whole. 2. The burner combustion control method in the aluminum melting furnace according to 2. 4. As an aluminum melting furnace, one of the multiple burners close to the exhaust port is arranged so that its combustion flame blocks the exhaust port, and the other burners are arranged so that its combustion flame blocks the surface of the molten metal in the furnace. 3. The combustion control method for a burner in an aluminum melting furnace according to claim 1, wherein a burner is used which is arranged so as to be directed obliquely and to form a swirling flow within the furnace as a whole. 5. The method for controlling burner combustion in an aluminum melting furnace according to claim 3 or 4, wherein a circular furnace is used as the aluminum melting furnace.