RU2817361C2 - Burner with display device, electric furnace equipped with said burner, and method of producing molten cast iron using said electric furnace - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, in particular to an electric furnace containing a burner with a display device for production of cast iron by melting cold iron raw material. Burner comprises a lens, a display device and a multi-tubular structure comprising an inner tube arranged around the lens, an outer tube arranged around the inner tube and separated from the inner tube by a coolant feed channel for the lens, a gaseous fuel supply pipe radially located outside the outer pipe and configured to inject gaseous fuel, a combustion-supporting gas supply tube radially located outside the outer tube and configured to inject the combustion-supporting gas, and a cooling tube, the most distant in the multi-tubular structure, which is located around the combustion-supporting gas supply tube.

EFFECT: invention makes it possible to visually observe the inner part of the furnace, in which cold iron raw material is heated by a burner, for efficient production of cast iron.

6 cl, 2 ex, 1 tbl, 4 dwg

Description

Field of technology

The present disclosure relates to a burner with a display device and, in particular, to a burner with a display device allowing an operator to use the burner to view the melting of cold iron raw materials in the production of molten pig iron. The present disclosure also relates to an electric furnace comprising a burner with a display device and configured to efficiently produce molten iron by melting cold iron raw materials. Additionally, the present disclosure relates to a method of using an electric furnace to efficiently produce molten iron. The burner with the display device can be installed, depending on the situation, in an electric furnace configured to produce molten iron from cold iron raw materials.

State of the art

When an electric furnace is used to melt cold iron raw materials such as scrap iron to produce molten pig iron, the cold iron raw materials in the melting chamber near the electrode melt quickly, but the cold iron raw materials far from the electrode in the so-called "cold spot" melts more slowly, resulting in unequal melting rates of the cold iron feedstock in the melting chamber. As a result, the problem is that the total working time of the electric furnace is determined by the melting speed of cold iron raw materials in a cold place.

To eliminate the uneven speed of melting cold iron raw materials and melting cold iron raw materials in the melting chamber in a well-balanced manner, a burner (auxiliary burner) is installed at a place where a cold spot may occur. The burner accelerates the melting of cold iron raw materials in a cold place.

For example, JP H10-9524 A (PTL 1) describes an electric furnace auxiliary burner having a three-tube design, whereby oxygen gas is injected from the center to spray onto unburnt material and cut scrap, fuel is injected from the periphery of oxygen gas, and oxygen gas is injected from the center. combustion is injected from the periphery of the fuel. In an auxiliary combustion burner conforming to PTL 1, a limiting portion is provided at the tip of the central oxygen gas injection tube to increase the speed of the central oxygen gas injection, and a swirl blade is provided in the inter-tube space formed by the fuel injection tube and the combustion oxygen gas injection tube to transferring the swirling motion to combustion oxygen gas injected from the outermost circumference.

Using the auxiliary burner described in PTL 1, the cold iron raw material in the melting chamber can be melted more evenly. However, since it is impossible to visually check the condition of the cold iron raw material in the melting chamber when the auxiliary burner is operating, determining whether the cold iron raw material is sufficiently melted depends on the operator's experience. For example, if the cold iron raw material present in the cold place is still not melted when using the auxiliary burner, the melting efficiency cannot be sufficiently increased. In addition, excessive heating of cold iron raw material in a cold location does not simply eliminate the cold spot, but instead stimulates the appearance of a hot spot, resulting in uneven temperature distribution of the molten iron in the melting chamber.

The inside of the melting chamber can, of course, be inspected by opening the slag plug, furnace lid, etc. However, when opening the oven, excess air enters from the outside, leading to significant heat loss. Additionally, the operator must get close to the furnace body, which can have disastrous consequences if molten iron or slag boils explosively. Therefore, optimizing burner ignition and extinguishing times is difficult in practice and efficient production of molten pig iron has been a challenge.

As a method for monitoring the interior of a furnace, JP H07-103670 A (PTL 2) proposes a monitoring device located inside the furnace that uses a television camera to obtain images of the interior of the furnace and monitor internal conditions via television images.

Citation list

Patent literature

PTL 1: JP H10-9524 A

PTL 2: JP H07-103670 A

Disclosure of the invention

Technical problem

However, when the inventors tried to observe the cold iron raw material in a cold place being melted by the burner by actually inserting the control device disclosed in PTL 2 into the electric furnace, the lens tip of the control device burned out in the high temperature environment of the electric furnace. Additionally, a situation was observed in which the lens tip became covered with molten slag, which splashed out, making it impossible to continue inspection.

In view of the problems described above, it would therefore be useful to provide a burner with a display device capable of clearly observing the inside of a furnace in which an object is being heated while the object is being heated by the burner. Additionally, it would also be useful to provide an electric furnace equipped with a burner with a display device, such that the electric furnace is capable of efficiently producing molten pig iron from cold iron raw materials, and a method for efficiently producing molten pig iron using the electric furnace.

Solution

As a result of studying the above-mentioned problems, the inventors have found that when the burner includes a lens and a display device and has a certain multi-tube structure, the burner can be effectively used while at the same time providing a good visual inspection of the inside of the furnace in which the object is heated by the burner. The inventors have also discovered that when a burner is used to efficiently produce molten pig iron from cold iron raw materials, the economic efficiency of production can be increased and the electrical power required for production can be reduced.

The main features of this disclosure are:

[1] A burner with a display device configured to burn gaseous fuel to form a flame, comprising a lens; a display device located behind the lens, where the side of the lens in the direction of the object to be displayed is defined as the front, and the opposite side of the lens in the direction of the object to be displayed along the optical axis of the lenses is defined as the rear; and a multi-tube structure comprising: an inner tube located around the lens; wherein the outer tube located around the inner tube is larger in diameter than the inner tube and is separated from the inner tube by a coolant flow path for cooling the lens; a gaseous fuel supply tube located radially outside the outer tube and configured to inject gaseous fuel in a forward direction from the lens; a combustion gas supply tube disposed radially outside the outer tube and configured to inject combustion gas in a forward direction from the lens; and a cooling tube, the outermost in the multi-tube structure, which is located around the gaseous fuel supply tube, and the combustion support gas supply tube.

According to the above disclosure, the front side of the lens is on the side of the object to be imaged, in other words, on the side on which the object to be heated by the burner is located, and also in the direction of the flame generated by the burner. For example, when the burner is installed through the wall of an electric furnace, the direction points towards the inside of the electric furnace. The back of the lens is the opposite side, directed along the optical axis of the lens, from the object to be imaged. For example, when the burner is installed through the wall of an electric furnace, the direction points outward outside the electric furnace.

[2] The burner with display device as set forth in [1], wherein a gaseous fuel supply tube having a larger diameter than the outer tube is disposed around the outer tube and is separated from the outer tube by a gaseous fuel passage path, the combustion support gas supply tube, larger in diameter than the gaseous fuel supply tube is located around the gaseous fuel supply tube and is separated from the gaseous fuel supply tube by a combustion gas supply channel; a refrigerant supply tube larger in diameter than the combustion gas supply tube is located around the supply tube combustion-supporting gas and is separated from the combustion-supporting gas supply tube by a refrigerant supply passage for the burner body, and the inner tube, outer tube, fuel gas supply tube, combustion-supporting gas supply tube and the refrigerant supply tube are installed coaxially.

[3] The burner with display device as set forth in [2], in which the tube holes in the axial direction of the tubes are arranged in the following order: an inner tube, an outer tube, and a gaseous fuel supply tube along the forward direction of the lens.

[4] An electric furnace equipped with a burner according to any one of paragraphs. [1]-[3], wherein the electric furnace is configured to melt cold iron raw materials to produce molten cast iron.

[5] A method for producing molten iron by melting cold iron raw materials using an electric furnace equipped with a burner, according to claims. [1]-[3], in which the operating conditions of the burner are controlled based on visual information received from the burner.

[6] The molten iron production method according to claim [5], wherein, when visual information received from the burner confirms the presence of adherent material on the front surface of the lens, a combustion supporting gas is injected from the combustion supporting gas supply tube or gas A combustion supporting gas is injected from the combustion supporting gas supply tube, and fuel gas is injected from the fuel gas supply tube to remove adhering material from the lens.

Preferred Result

According to the present disclosure, when an object is heated by a burner, the inside of the furnace in which the object is heated (the object to be displayed) can be clearly observed.

In the operation of the burner, when the inside of the furnace in which the object is heated is observed, such as when the cold iron raw material is melted in the electric furnace to produce molten pig iron, the cold iron raw material in the cold place can be effectively melted, and the temperature of the molten pig iron can be evenly controlled, which is effective in reducing production costs and provides exceptional benefits for industry.

Brief description of drawings

On the accompanying drawings:

Fig. 1 is a longitudinal sectional view of a burner with a display device according to an embodiment of the present disclosure, viewed from the side;

Fig. 2A and 2B are longitudinal sectional views of a burner with a display device according to at least one embodiment of the present disclosure, viewed from the front. Fig. 2A shows an example in which each tube is installed coaxially and FIG. 2B shows an example in which gaseous fuel supply tubes and combustion fuel supply tubes are installed non-coaxially;

Fig. 3 is a longitudinal sectional view of a burner with a display device according to an embodiment of the present disclosure installed in an electric furnace; And

Fig. 4 is a sectional view of a burner with a display device according to an embodiment of the present disclosure installed in an electric furnace.

Carrying out the invention

The following describes embodiments of the present disclosure.

The following description merely describes preferred exemplary embodiments and the present disclosure is in no way limited to the examples described.

Burner

According to the present disclosure, a burner including a lens and a display device has a certain multi-tube structure comprising an inner tube which is disposed around the lens, an outer tube which is disposed around the inner tube, a gaseous fuel supply tube configured to inject gaseous fuel, a tube a combustion gas supply configured to inject a combustion gas, and the latter cooling tube. The specific design of the torch with the display device allows the heating of the object by the torch to be clearly observed, even at very high temperatures exceeding 1000°C. Therefore, when using a burner, the operating conditions can be controlled while visually checking the heating conditions due to the burner at very high temperatures, such as those found in an electric furnace. As a result, for example, when producing molten pig iron from cold iron raw materials in an electric furnace, the melting efficiency of the cold iron raw materials by the torch can be improved and production costs can be reduced. The burner is particularly suitable during the production of molten pig iron from cold iron raw materials in an electric furnace for use as an auxiliary burner to accelerate the melting of unmelted cold iron raw materials in a so-called cold place.

Next, with reference to the drawings, a description is given of a preferred embodiment of the burner.

Lens

The burner 1 includes a lens 7 and a display device 8 located behind the lens 7. The lens 7 is preferably a Rayleigh lens containing multiple lenses. The Rayleigh lens allows separation of the axial length of the front surface of the lens 7 from the display device 8. For example, when installing the burner 1 in the electric furnace 90, this allows the front side of the lens 7 to be positioned inside the furnace to clearly obtain an image of the object to be displayed, while allowing the display device 8 to be located outside the furnace to protect the display device 8 from high temperature and simplify operation.

Display device

A display device 8 is provided behind the lens 7 and receives and, if desired, records an image of an object formed by the lens 7. For example, when the burner 1 is installed in the electric furnace 90, the display device 8 is preferably installed outside the electric furnace 90 as described above. The display device 8 is typically a camera and is preferably protected by a housing 83. To further protect the display device 8 from the heat of the electric furnace 90, coolant 80 for the display device preferably flows through a coolant supply port 81 and a coolant outlet 82 provided anywhere on the housing 83 The coolant 80 for the display device may be a liquid such as water or any gas, but for ease of operation is preferably a gas, and more preferably air or an inert gas such as nitrogen.

The video received by the display device 8 is typically transmitted via a connecting cable (not shown) to a monitor or recording device (not shown) in the control room in which the operator is working.

Inner tube

The inner tube 6 is located around the lens 7. The inner tube 6 is located around the lens 7, thereby protecting the lens 7 and physically protecting the lens 7 from the environment such as heat, adhesive materials, etc. The inner tube 6 can be connected with the housing 83 to further protect the display device 8. The outer diameter of the inner tube 6 is not limited to any particular value, but from the viewpoint of ensuring the flow rate of the coolant 70 for the lens described below and at the same time reducing costs, the outer diameter is preferably 100 mm or less, and usually 20 mm or more.

The inner tube 6 may have a tubular shape and the material properties should be selected accordingly, taking into account the ambient temperature and the strength of the installation site. In terms of cost, carbon steel, stainless steel, etc. are preferable.

When the lens 7 is a Rayleigh lens, the inner tube 6 and the lens 7 are preferably mounted coaxially.

Outer tube

An outer tube 5, larger in diameter than the inner tube 6, is located around the inner tube 6 and is separated from the inner tube 6 by a lens coolant supply channel. By using a multi-tube structure with an outer tube 5 arranged around an inner tube 6, the lens 7 can be better protected from high ambient temperature. Additionally, the outer tube 5 is arranged around the inner tube 6 separated by the lens coolant passageway, allowing the lens coolant 70 to flow through the passageway in the space between the inner tube 6 and the outer tube 5, further protecting the lens 7 from high ambient temperature. For example, when the lens coolant 70 flows in a forward direction from the lens 7 through the coolant supply port 71 and the coolant outlet 72 arranged as shown for the outer tube 5 in FIG. 1, the lens coolant 70 can be effectively used to remove molten iron 96 and molten slag splashing from the electric furnace 90, and thus avoid them from sticking and depositing on the front surface of the lens.

For example, in order to pass the lens coolant 70 into the electric furnace 90 without affecting the composition of the molten iron 96 in the furnace 90, the lens coolant 70 is preferably a gas, and more preferably air or an inert gas such as nitrogen. The flow rate of the lens coolant 70 is preferably 50 Nl/min or more. The unit "nl/min" is a unit of flow rate commonly used in this technical field and can generally be thought of as "l/min".

The outer tube 5 may be connected to the housing 83 to further ensure the security of the display device 8. The inner and outer diameters of the outer tube 5 are not limited to any particular values, but from the viewpoint of ensuring the flow rate of the lens coolant 70 while reducing costs, the inner diameter is preferably 120 mm or less and may be 30 mm or more. From the point of view of reducing costs while maintaining the flow rate of the gaseous fuel 40 described later, the outer diameter is preferably 40 mm or larger.

The outer tube 5 may be tubular in shape and the material properties must be selected accordingly, taking into account the ambient temperature and the strength of the installation site. From the cost point of view, carbon steel, stainless steel, etc. are preferable.

When the lens 7 is a Rayleigh lens, the outer tube 5, the inner tube 6 and the lens 7 are preferably mounted coaxially. The hole in the axial direction of the outer tube 5 (in FIG. 1, the tip on the left side of the outer tube 5) is preferably located further forward from the lens 7 than the hole in the axial direction of the inner tube 6 (in FIG. 1, the tip is on the left side of the inner tube 6 ). By maintaining the front surface of the lens 7 in this manner, molten cast iron 96 and molten slag splashing from the electric furnace 90 can be better avoided from sticking and depositing onto the front surface of the lens.

Gas fuel supply pipe

The gaseous fuel supply tube 4 is positioned radially towards the outer tube 5 and is configured to inject gaseous fuel 40 in a forward direction from the lens 7. The injected gaseous fuel 40 is burned in the electric furnace 90, for example, shaping the flame of the burner 1 so as to target and melt the cold iron raw material 94, which is not molten.

The gaseous fuel supply tube 4 may be larger in diameter than the outer tube 5, located around the outer tube 5, and separated from the outer tube 5 by a gaseous fuel supply channel, as shown in FIG. 1 and fig. 2A, and may be installed as one or multiple tubes near the outer circumference of the outer tube 5, as shown in FIG. 2B. The installations shown in FIG. 1 and fig. 2A are preferred. By using a multi-tube structure of multiple gaseous fuel supply tubes 4 further arranged around the outer tube 5, the lens 7 can be further protected from high ambient temperature. Further, since the gaseous fuel supply tube 4 is disposed around the outer tube 5, separated from it by the gaseous fuel supply passage, the gaseous fuel 40 can be injected through the passage into the space between the outer tube 5 and the gaseous fuel supply tube 4 disposed around the outer tube 5, and therefore, for example, molten iron 96 and molten slag sprayed into the electric furnace 90 can also be blown away by the gaseous fuel 40, and this can be effectively used to prevent them from sticking and depositing on the front surface of the lens. For example, the gaseous fuel 40 may be injected forward in front of the lens 7 through the gaseous fuel supply port 41 and the gaseous fuel injection port 42 arranged as shown for the gaseous fuel supply tube 4 in FIG. 1.

As the gaseous fuel 40, examples include liquefied petroleum gas (LPG), liquefied natural gas (LNG), hydrogen, steel mill by-product gas (C gas, B gas, etc.), and a mixed gas containing two or more of these gases, each of which may be used alone or in combination with another gas.

The flow rate of the gaseous fuel 40 is preferably 150 Nl/min or more. The gaseous fuel supply tube 4 may be fixed at the connection with the outer tube 5. The inner and outer diameters of the gaseous fuel supply tube 4 are not limited to any specific values, but from the viewpoint of ensuring the flow rate of the gaseous fuel 40 and reducing costs when the gaseous fuel supply tube 4 The fuel is arranged around the outer tube 5, the inner diameter is preferably 140 mm or less and may be greater than 40 mm. From the point of view of reducing costs while maintaining the flow rate of the combustion supporting gas 30 described below, the outer diameter is preferably 50 mm or larger.

The gaseous fuel supply pipe 4 may be tubular in shape, and the material properties should be suitably selected in consideration of the ambient temperature and the strength of the installation site. From the cost point of view, carbon steel, stainless steel, etc. are preferable.

When the lens 7 is a Rayleigh lens, the gaseous fuel supply tube 4, the outer tube 5, the inner tube 6 and the lens 7 are preferably mounted coaxially. The hole in the axial direction of the gaseous fuel supply tube 4 (in FIG. 1, the tip on the left side of the gaseous fuel supply tube 4) is preferably located further forward from the lens 7 than the hole in the axial direction of the outer tube 5 (in FIG. 1, the tip on the left side of the outer tube 5). By further supporting the front surface of the lens 7 in this manner, molten cast iron 96 and molten slag splashing from the inside of the electric furnace 90 can be further avoided from sticking and depositing on the front surface of the lens.

Combustion gas supply tube

The combustion gas supply tube 3 is positioned radially outside the outer tube 5 and is configured to inject combustion gas 30 forward from the lens 7. The combustion gas 30 that is injected helps burn the gaseous fuel 40 described above and the gaseous the fuel 40 is burned in the electric furnace 90, for example, shaping the flame from the burner 1 so as to aim it and melt the cold iron raw material 94, which is not molten.

The combustion gas supply tube 3 may be larger in diameter than the gaseous fuel supply tube 4, is disposed around the gaseous fuel supply tube 4, and is separated from the gaseous fuel supply tube 4 by a combustion gas supply passage, as shown in FIG. 1 and fig. 2A, and may be installed as a single tube or as a plurality of tubes around the outer circumference of the outer tube 5, as shown in FIG. 2B. The structures shown in FIGS. 1 and fig. 2A are preferred. By using the quadruple tube structure together with the combustion gas supply tube 3 further arranged around the gaseous fuel supply tube 4, the lens 7 can be further protected from high ambient temperature. Additionally, since the combustion gas supply tube 3 is arranged around the gaseous fuel supply tube 4 separated by the combustion gas supply passage, the combustion support gas 30 can be injected through the passage in the space between the gaseous fuel supply tube 4 and the supply tube 3 combustion-supporting gas disposed around the gaseous fuel supply tube 4, and therefore, for example, molten iron 96 and molten slag splashing from the electric furnace 90 can be blown away by the combustion-supporting gas 30 to better prevent them from sticking and depositing on the front surface of the lens. For example, the combustion gas 30 may be injected forward from the lens 7 through the combustion gas supply port 31 and the combustion gas supply port 32 arranged as shown for the combustion gas supply tube 3 in FIG. 1.

The combustion support gas 30 may be pure oxygen (commercial oxygen), oxygen-enriched air or air, but when melting the cold iron raw material 94 in the electric furnace 90, pure oxygen is preferred.

The flow rate of the combustion support gas 30 is preferably 300 Nl/min or more. The combustion gas supply tube 3 may be fixed at the junction with the gaseous fuel supply tube 4. The inner and outer diameters of the combustion support gas supply tube 3 are not limited to any particular values, but from the viewpoint of ensuring the flow rate of the combustion support gas 30 and reducing costs when the combustion support gas supply tube 3 is arranged around the combustion support gas supply tube 4 fuel, the inner diameter is preferably 150 mm or less and may be greater than 50 mm.

The combustion gas supply tube 3 may be tubular in shape, and the material properties should be suitably selected in consideration of the ambient temperature and the strength of the installation site. From a cost point of view, carbon steel, stainless steel, etc. may be preferable.

When the lens 7 is a Rayleigh lens, the combustion gas supply tube 3, the gaseous fuel supply tube 4, the outer tube 5, the inner tube 6 and the lens 7 are preferably mounted coaxially.

Cooling pipe

The cooling tube 2 is located around the gaseous fuel supply tube 4 and the combustion gas supply tube 3, and is located in the most distant part of the burner body. For example, when the burner body coolant 20 flows through the coolant supply port 21 and the coolant outlet 22 arranged as shown for the cooling pipe 2 in FIG. 1, The burner body can be used in high temperature environments such as 90 electric furnace, while cooling the burner body. For example, even when molten iron 96 is produced from cold iron raw material 94 in the electric furnace 90, the burner body coolant 20 may be discharged to the outside of the furnace through the coolant outlet 22, and therefore, from the point of view of cooling efficiency, the burner body coolant 20 is preferably a liquid and water is preferably used.

When the burner 1 is used at high temperatures, icicle-like masses may form at the front end of the cooling tube 2. Even in such cases, the flame of burner 1 is capable of melting icicle-like masses, keeping the image field clear.

The material properties of the cooling tube 2 must be selected accordingly with respect to the ambient temperature and the strength of the installation site. From the cost point of view, carbon steel, stainless steel, etc. are preferable.

Electric furnace

The electric furnace according to the present disclosure is an electric furnace for melting cold iron raw materials to produce molten iron, and is equipped with a burner with a display device as described above. When the electric furnace is equipped with the described burner with a display device, the burner can be used while visually checking in a cold place the cold iron raw material melted by the burner. Accordingly, inappropriate melting and excessive melting by the burner can be prevented, melting efficiency can be improved and production costs can be reduced.

Apart from having the burner 1, the electric furnace 90 is not limited to any particular method and can be used as a conventional electric furnace. In fig. 3 schematically shows the cold iron raw material 94 being melted in the melting chamber of the electric furnace 90 by the heat generated by the electrode 92 and the flame of the burner 1 to produce molten iron 96. In the cold place in the melting chamber, which is relatively far from the electrode 92, the cold iron raw material 94 cannot be produced enough heat from electrode 92 and can remain unmelted. The electric furnace is equipped with a specific burner and therefore the burner can be used only when necessary with certainty of the presence or absence of cold iron raw material 94, which is not molten.

The location of the burner 1 is not limited to any particular location as long as the cold iron raw material 94 in the cold place is in view, and the burner 1 is preferably installed through the furnace wall of the melting chamber, as shown in FIG. 3. This arrangement allows the front side of the lens 7 to be positioned in the furnace to clearly obtain an image of the cold iron raw material 94 in the furnace, while the display system 8 is located outside the furnace to protect the display system 8 from high temperature and simplify operation. The angle and height at which the burner 1 is installed are respectively selected so that the image of the cold iron raw material 94 can be clearly seen.

Additionally, the burner 1 is preferably installed such that at least the oxygen purging lance 97 or the carbon material purging lance 98 is in the field of view, both of which are described below, or more preferably, such that both are in the field of view. . When the burner 1 can also be used to visually inspect the oxygen blowing lance 97 and/or the carbon material blowing lance 98, the operating conditions of the oxygen blast lance 97 and/or the carbon material blowing lance 98 can be controlled even more effectively. For example, when it is confirmed that the cold iron raw material 94 is sufficiently molten, the blowing volume from the oxygen purging lance 97 and/or from the carbon material purging lance 98 may be reduced or stopped. So that the burner 1 can also be used to image the oxygen purge lance 97 and/or the carbon purge lance 98, the field of view of the burner 1 can be expanded or a new burner with a display device can be installed to monitor the oxygen purge lance 97 and the carbon purge lance 98 .

Method for producing molten iron

The production method is a method for producing molten iron by melting cold iron raw materials, and comprises controlling the operating conditions of the burner based on visual information received from the burner with the display device described above. The production method in this case gives the same results as the electric furnace described above.

The production method is not particularly limited, and the usual process can be carried out except that an electric furnace equipped with a particular display burner is used, and visual information obtained from the display burner is used. In fig. 4 schematically shows molten iron 96 produced using an electric furnace 90 equipped with a plurality of burners 1. Cold iron raw material 94 is supplied to the melting chamber of the electric furnace 90 and the heat generated by the electrode 92 melts the cold iron raw material 94 into molten iron 96. Preheating the cold iron raw material 94 before feeding into the melting chamber can improve the melting efficiency. During melting, carbon material as an auxiliary heat source may be further supplied from the carbon material purging lance 98, and oxygen for decarburization may be further supplied from the oxygen purging lance 97. Additionally, the cold iron raw material 94, which is present in the cold place and which is not molten, is intensively melted by the burner 1 to efficiently produce molten iron 96. The molten iron 96 accumulated in the melting chamber can be discharged from the furnace through any discharge port on the discharge side. molten cast iron. The molten slag produced together with the molten iron 96 may be discharged from the furnace through any auxiliary outlet on the auxiliary slag outlet side.

According to the present disclosure, the burner 1 can be used based on visual information received from the burner 1, for example, when checking the melting state of the cold iron raw material 94, and this can optimize the operating conditions of the burner 1 without dangerous operations. It is useful in molten iron production processes to improve the economic efficiency of production and reduce production costs.

Specifically, for example, when visual information received from the burner 1 confirms that the cold iron raw material 94 is not melted, the burning speed of the burner 1 is preferably increased to accelerate melting. On the other hand, when visual information received from the burner 1 confirms that the cold iron raw material 94 in the cold location has already been molten, the burning speed of the burner 1 is preferably reduced or the burner 1 is extinguished in order to control unnecessary power consumption due to excess heating and prevent iron oxidation.

Traditional burners do not have a display device 8, and with them, when operating the burner, it was impossible to practically check the melting state of the cold iron raw material 94. Therefore, according to traditional technology, the burners were used based on the operator's experience, and there was a tendency to abuse the operation of the burner in order to Do not leave cold iron raw materials unmelted. However, according to the present disclosure, the operating conditions of the burner can be controlled in a timely manner by visually checking the melting state of the cold iron raw materials and allowing the operating conditions of the burner to be optimized so as to handle the cold iron raw materials 94 that have not melted in a highly efficient manner.

During the production of molten iron, molten iron 96 and molten slag may splash out in the furnace and stick and deposit on the front surface of the torch lens 1, narrowing the field of view of the resulting image. When visual information received from the burner 1 confirms the presence of material adhered to the front surface of the lens, the adhered material is preferably removed from the lens by injecting combustion gas 30 supplied from the combustion gas supply tube 3, or further by injecting more gaseous fuel 40 from the gaseous fuel supply tube 4. For example, when it is confirmed that slag has adhered or settled on the front surface of the lens, only combustion support gas 30 is first injected to oxidize the iron in the slag and generate oxidation reaction heat that can re-melt and remove the adhered or deposited slag. When this fails to remove the adhered or deposited slag, gaseous fuel 40 may be injected in addition to the combustion support gas 30, and the combustion heat of the flame generated additionally will also melt the slag to remove the adhered or deposited slag. Thus, by constantly monitoring the cold iron raw material 94, the melting efficiency corresponding to the burner can be optimized.

Additionally, the burner 1 is more preferably used to inspect at least one, and more preferably both, of the oxygen purge lance 97 and the carbon material purge lance 98 and, when unmelted cold iron raw material 94 is detected, to increase the purge volume of the oxygen purge lance 97 and/or or a carbon material purge tuyere 98 to further promote melting. On the other hand, when it is confirmed that the cold iron raw material 94 has already been melted by the burner 1, the blowing volume of the oxygen blowing lance 97 and/or the carbon material blowing lance 98 is more preferably reduced or stopped.

Examples

Specific examples of the present disclosure are described below. The following examples merely show preferred examples and the present disclosure is not limited in any way to the examples described. Additionally, the following examples may be modified without departing from the scope and spirit of the present disclosure, and such modifications are also contained within the technical scope of the present disclosure.

Example 1

An electric furnace 90 with a burner 1 shown in FIG. 1 and installed as schematically shown in FIG. 3 and fig. 4 was used to melt cold iron raw materials 94 to produce molten pig iron 96. The electric furnace 90 was a direct current electric furnace having a furnace diameter of approximately 6.3 m, a furnace height of 4.1 m and a steel capacity of approximately 120 tons, with an oxygen purge tuyere 97 and a lance 98 for blowing carbon material, cooled by water and installed in the furnace from above, and an electrode 92 installed separately in the center of the furnace horizontally. A plurality of burners 1 (No. 1, No. 2, No. 3) were installed through the furnace wall in a total of three locations distributed approximately evenly around the perimeter of the furnace body (see FIG. 3).

The basic operating conditions for the electric furnace are listed below.

Feeding weight of cold iron raw materials: approximately 130 tons

Feeding weight of cold iron raw materials at one time: approximately 65 tons

Number of supplied cold iron raw materials: 2

Cold iron raw material type: Heavy H2 (according to the "Uniform Standards of Ferrous Scraps" of the Japanese Raw Iron Materials Association)

Steel yield per load: approximately 120 tons

Target temperature of molten metal when leaving the furnace: 1580°C

Target carbon concentration at kiln outlet: 0.060%.

Coke feed weight (recycled raw materials): 1000 kg

Lime supply weight (recycled raw material): 500 kg

Oxygen purge flow rate (pure oxygen): from 0 Nm ³ /h to 5000 Nm ³ /h

Carbon material purge flow rate (coke slag): 0 kg/min to 100 kg/min, carbon material carrier gas (air) flow rate: approximately 350 Nm ³ /h

Flow rate of gaseous fuel (LNG) per burner 1: from 0 Nm ³ /h to 350 Nm ³ /h

Flow rate of combustion gas (pure oxygen) per burner 1: from 0 n.m ³ /h to 770 n.m ³ /h

Coolant flow rate for lens (air) per burner 1: 8 n.m ³ /h

Cold iron raw materials 94 were supplied from the ladle to the electric furnace 90 on two separate occasions, before and after the operation. Before the operation, as auxiliary fuel, coke masses and auxiliary lime material were supplied to the electric furnace 90 through an auxiliary fuel supply chute (not shown).

The cold iron raw material 94 was melted while pure oxygen and coke slag were supplied through the oxygen blowing lance 97 and the carbon material blowing lance 98, respectively.

Here, during the smelting process, the burner 1 was used to observe the cold iron raw material 94 at three cold places distant from the electrode 92, and the operating conditions of the burner 1 were accordingly changed based on the obtained visual information. Specifically, when it was determined that there was a cold iron raw material 94 that had not been melted, the flow rate of the gaseous fuel 40 and/or the flow rate of the combustion support gas 30 of the burner 1, which is used to image the cold iron raw material 94, was increased within the above limits until confirmation was received that all cold iron raw materials 94 had been melted. On the other hand, when it was confirmed that all of the cold iron raw material 94 had melted to become molten iron 96, the flow rate of the gaseous fuel 40 and/or the flow rate of the gas 30 supporting combustion of the burner 1, which was used to image the molten iron 96, decreased within the above limits or burner 1 has been extinguished.

Additionally, when visual information from the burner 1 confirmed that material had adhered to the lens 7, the flow rate of the combustion support gas 30 and, if necessary, the flow rate of the gaseous fuel 40 of the burner 1, which was used to obtain an image of the adhered material, were increased in the above limits until confirmation has been received that the adhering material has been removed. This ensured a clear field of vision during the operation.

The single batch melting process was completed when 120 tons of molten 96 iron were produced and the molten 96 iron was removed from the outlet into a ladle outside the furnace. This was repeated for 20 loads. The target tapping temperature of molten iron 96 was approximately 1580°C and the target carbon concentration of molten cast iron 96 was 0.060 wt.% and, according to Example 1, the average tapping temperature of molten iron 96 was 1600°C and the average carbon concentration was 0.056 wt. .%.

The average values of production time, electricity consumption, oxygen consumption consumption, coke consumption and gaseous fuel consumption and combustion gas consumption per burner 1 were calculated. The results are shown in Table 1. Here, each consumption can be calculated as a value in per ton of molten cast iron produced.

Example 2

In Example 2, molten 96 iron was produced for 20 batches under the same conditions as Example 1 except for the following points. According to Example 2, the cold iron raw material 94 in the vicinity of the oxygen purging lance 97 and the carbon material purging lance 98 was also observed by the burner 1 during the melting process, and the operating conditions of the oxygen purging lance 97 and the carbon material purging lance 98 were also changed accordingly based on the obtained visual information. Namely, when the presence of cold iron raw material 94 that was not melted was determined, the purge flow rate from the oxygen purge lance 97 and the purge flow rate from the carbon material lance 98 increased within the above-mentioned limits. On the other hand, when it was confirmed that all of the cold iron raw materials 94 had been melted into the state of molten iron 96, the flow rate from the oxygen purging lance 97 and the flow speed from the carbon material purge lance 98 were reduced within the above limits or stopped.

The target tapping temperature of molten iron 96 was approximately 1580°C and the target carbon concentration of molten cast iron 96 was 0.060 wt.% and, according to Example 2, the average tapping temperature of molten iron 96 was 1590°C and the average carbon concentration was 0.058 wt. .%.

The average values of production time, electricity consumption, oxygen consumption, coke consumption and consumption of gaseous fuel and combustion gas per 1 burner were calculated. The results are shown in Table 1.

Comparative example

The operating conditions of the burner 1 were controlled based on the operator's experience without using the burner 1 display device 8 and without visually confirming the melting state of the cold iron raw material 94. Otherwise, molten pig iron 96 was produced for 20 batches under the same conditions as in Example 1 and in Example 2.

The target tapping temperature of molten iron 96 was approximately 1580°C and the target carbon concentration of molten cast iron 96 was 0.060 wt.% and, according to the comparative example, the average tapping temperature of molten iron 96 was 1640°C and the average carbon concentration was 0.054 wt.%.

The average values of production time, electricity consumption, oxygen consumption, coke consumption and consumption of gaseous fuel and combustion gas per 1 burner were calculated. The results are shown in Table 1.

As can be seen from Table 1, compared to the comparative example, in Examples 1 and 2, energy consumption and production time are reduced. Oxygen flow rate, coke flow rate, burner fuel gas flow rate and burner gas flow rate were also reduced as seen in Examples 1 and 2. This is because in Examples 1 and 2 the furnaces were operated with visual inspection of the internal conditions of the furnace, which , in particular, can quickly check and determine the melting state of cold iron raw materials in cold places, and immediately control the operating conditions of the burner to effectively suppress unnecessary blowdown of the burners.

Additionally, the rapid confirmation of melting of the cold iron raw materials also made it possible to supply additional cold iron raw materials at appropriate times to maintain continuous operation. The additional supply of cold iron raw materials affects production time and energy consumption. When the additional supply of cold iron raw materials occurs too early, new cold iron raw materials may be supplied on top of the semi-molten or unmelted cold iron raw materials in the furnace, causing them to sinter together and form large arrays. This disrupts the melting process, resulting in longer production times and increased energy consumption. When the additional supply of cold iron raw material occurs too late, electricity is wasted and the molten iron becomes overheated. This again results in longer production times and increased energy consumption.

In the case of Examples 1 and 2, the torch, lens and display device are integrated into a single unit, and the heat generated from the torch successfully avoids sticking or deposition of material such as slag on the front side of the lens. Additionally, even when material such as slag adhered or deposited on the front side of the lens, the condition of the front side of the torch lens could always be checked through the display device and therefore the torch could be used to eliminate obstructions in the field of view caused by adherence or deposition of material such as slag , by immediately injecting combustion gas or gaseous fuel as required. In this way, the condition of the cold iron raw material in the furnace could be constantly checked during operation.

Additionally, according to Example 2, the operating conditions of the oxygen purging lance 97 and the carbon material purging lance 98 were also adjusted based on visual information using a burner, which further improved the melting efficiency. Specifically, when blown with oxygen and carbon material, combustion of the carbon material created carbon monoxide gas, which promotes what is called “slag formation,” in which the molten slag bubbles. At the same time, the formation of slag has the effect of reducing the radiant heat of the arc and increasing the melting efficiency of cold iron raw materials, observing the state of molten iron and molten slag through the torch could prevent excessive blowing of oxygen and carbon material, and the state of slag formation could be successfully created and maintained. This has led to further improvements in melting efficiency and further reductions in energy consumption and production time.

Industrial applicability

According to the present disclosure, when an object is heated by a burner, the interior of the furnace in which the object is heated can be clearly observed, reducing production costs for the furnace.

List of reference items

1 Burner (with display device)

2 Cooling pipe

20 Burner body coolant

21 Refrigerant supply port

22 Refrigerant release

3 Combustion gas supply tube

30 Combustion gas

31 Combustion gas supply port

32 Combustion gas injection port

4 Gas fuel supply pipe

40 Gaseous fuel

41 Gas fuel supply port

42 Gas fuel injection port

5 Outer tube

6 Inner tube

7 Lens

70 Lens coolant

71 Refrigerant supply port

72 Refrigerant release

8 Display device

80 Refrigerant for display device

81 Refrigerant supply port

82 Refrigerant release

83 Case

90 Electric oven

92 Electrode

94 Cold iron raw materials

96 Molten Iron

97 Oxygen purge lance

98 Carbon material blowing lance

Claims (19)

1. A burner with a display device, configured to burn gaseous fuel to form a flame, containing: lens; a display device located behind the lens, wherein the side of the lens in the direction of the object to be displayed is defined as the front, and the opposite side of the lens in the direction of the object to be displayed along the optical axis of the lens is defined as the rear; And multi-tubular structure containing: an inner tube located around the lens; an outer tube arranged around an inner tube which is larger in diameter than the inner tube and separated from the inner tube by a lens coolant supply passage; a gaseous fuel supply tube located radially outside the outer tube and configured to inject gaseous fuel in a forward direction from the lens; a combustion gas supply tube disposed radially outside the outer tube and configured to inject combustion gas in a forward direction from the lens; And a cooling tube located outermost in the multi-tube structure, which is located around the gaseous fuel supply tube and the combustion support gas supply tube. 2. Burner according to claim 1, in which the gaseous fuel supply tube has a diameter larger than the diameter of the outer tube, is located around the outer tube and is separated from the outer tube by a gaseous fuel supply channel, the combustion support gas supply tube has a diameter larger than the diameter of the gaseous fuel supply tube, is located around the gaseous fuel supply tube and is separated from the gaseous fuel supply tube by a combustion support gas supply channel, the refrigerant supply tube has a diameter larger than the diameter of the combustion gas supply tube, is located around the combustion gas supply tube and is separated from the combustion gas supply tube by a refrigerant supply channel for the burner body, wherein the inner tube, outer tube, gaseous fuel supply tube, combustion gas supply tube and refrigerant supply tube are installed coaxially. 3. The burner according to claim 2, in which the holes of the tubes in the axial direction of the tubes along the forward direction from the lens are arranged in the following order: an inner tube, an outer tube and a gaseous fuel supply tube. 4. An electric furnace equipped with a burner with a display device according to any one of claims. 1-3, wherein the electric furnace is configured to melt cold iron raw materials to produce molten cast iron. 5. A method for producing molten iron by melting cold iron raw materials using an electric furnace equipped with a burner with a display device according to any one of claims. 1-3, in which the operating conditions of the burner are controlled based on visual information received from the burner. 6. The method of claim 5, wherein when visual information received from the torch confirms the presence of material adhering to the front surface of the lens, combustion gas is injected from the combustion gas supply tube, or combustion gas is injected from the combustion gas supply tube, and gaseous fuel is injected from the fuel gas supply tube to remove adhering material from the lens.