System and control method for reducing molten metal losses in a gas-fired melting furnace

Abstract

The present application relates to a kind of systems for reducing the burn loss of molten metal in gas melting furnace, the gas melting furnace includes circular furnace body and at least one group of combustion device, each group of combustion device includes regenerative burner, regenerator, gas pipe, the low-nitrogen burner is provided with the side of the outlet of regenerative burner, the main gas inlet pipe is connected between the regenerative burner and regenerative burner, the secondary gas inlet pipe is connected between gas pipe and low-nitrogen burner, first gas solenoid valve is equipped on the gas pipe, second gas solenoid valve is equipped on the main gas inlet pipe, third gas solenoid valve is equipped on the secondary gas inlet pipe.Two kinds of switchable combustion mode are provided, when the temperature in furnace is >900 degrees, the direct injection flame combustion in hearth is changed into diffuse flame combustion, makes flame distribution uniform, thereby improves the rapid melting of metal waste in furnace, reduces the oxidation of metal material, while reducing the emission content of nitrogen oxides.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aluminum processing, in particular to a system and control method for reducing smelting metal burning loss of a gas melting furnace. BACKGROUND

[0002] The 75-ton circular fixed gas melting furnace mainly adopts natural gas combustion. The furnace adopts four regenerative burners (two sets), and the single power is 7500kw. Each burner is independently configured with an independent combustion system and device, and direct injection combustion is performed through the regenerative main burner. The direct injection flame is sprayed to the surface of the furnace charge until it is melted. And the aluminum water is in contact with air for a long time, which is easy to oxidize under the combustion of high-temperature burners, and slagging and other phenomena occur. At present, the proportion of waste materials is high, and the direct injection combustion easily causes the burning loss of metal waste in the furnace to increase greatly, causing unnecessary loss. SUMMARY

[0003] Therefore, the purpose of the present application is to provide a system for reducing smelting metal burning loss of a gas melting furnace, which has two switchable combustion modes. By changing the combustion mode, the flame is evenly distributed, thereby improving the rapid melting of metal waste in the furnace, reducing the oxidation of metal materials, and reducing the content of nitrogen oxide emissions.

[0004] The present application adopts the following scheme: a system for reducing smelting metal burning loss of a gas melting furnace, the gas melting furnace comprising a circular furnace body and at least one set of combustion devices, each set of combustion devices comprising a regenerative burner, a regenerative chamber, and a gas pipe, a low-nitrogen burner is provided beside the outlet of the regenerative burner, a main gas inlet pipe is connected between the gas pipe and the regenerative burner, a secondary gas inlet pipe is connected between the gas pipe and the low-nitrogen burner, a first gas solenoid valve is provided on the gas pipe, a second gas solenoid valve is provided on the main gas inlet pipe, and a third gas solenoid valve is provided on the secondary gas inlet pipe.

[0005] Further, a manual ball valve and a gas pressure sensor are respectively provided on the gas pipe, the main gas inlet pipe, and the secondary gas inlet pipe.

[0006] Further, a flame high-temperature camera is provided on the circular furnace body wall above the regenerative burner.

[0007] Further, a first temperature sensor is provided on the top of the circular furnace body, and a second temperature sensor is provided on the side of the circular furnace body; all gas solenoid valves and flame high-temperature cameras are electrically connected with a combustion controller, and the gas pressure sensor, temperature sensor, and combustion controller are electrically connected with a PLC controller.

[0008] Further, the combustion device is four sets, two sets of combustion devices form a combustion system, and the two sets of combustion devices of the combustion system are arranged on opposite sides of the circular furnace body.

[0009] Another technical solution of the present application: a control method of the system for reducing the molten metal burning loss of the gas melting furnace, the regenerative burner is started to perform direct injection combustion; when the temperature in the furnace is greater than 900 degrees, the low-nitrogen burner is started to perform dispersion combustion, and the regenerative burner is closed; when the temperature in the furnace is less than 900 degrees, the regenerative burner is started again to perform direct injection combustion, and the low-nitrogen burner is closed.

[0010] Further, the flame high-temperature camera monitors the flame state in the furnace in real time, once the flame signal loss or the camera failure is detected, the flame failure is detected by the combustion controller, the gas is immediately cut off, and the signal is fed back to the PLC controller to close the combustion device.

[0011] Further, when the gas pressure sensor senses that the gas pressure is less than or equal to 0.1 MPa, an alarm is given, and the gas is quickly cut off.

[0012] Further, before the low-nitrogen burner is started, it is ensured that the temperature difference detected by the first temperature sensor and the second temperature sensor in the furnace is not more than ±2 degrees, which is used as the condition judgment for starting the low-nitrogen burner.

[0013] Further, the two groups of combustion devices of the same set of combustion system are alternately switched according to time.

[0014] Compared with the prior art, the present application has the following beneficial effects: the system for reducing the molten metal burning loss of the gas melting furnace has two switchable combustion modes, when the temperature in the furnace is greater than 900 degrees, the direct injection flame combustion in the furnace is changed to dispersion flame combustion by changing the combustion mode, the flame is uniformly distributed, thereby improving the rapid melting of the metal waste in the furnace, reducing the oxidation of the metal material, and reducing the content of nitrogen oxide emissions. Therefore, whether from the energy saving effect and the product quality has been significantly improved compared with before, the production cost is reduced, and good economic and social benefits are obtained.

[0015] In order to make the purpose, technical scheme and advantages of the present application more clear, specific examples and related drawings will be used to further illustrate the present application. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a top view of the prior art gas melting furnace;

[0017] Figure 2 is a sectional view of the gas melting furnace according to the embodiment of the present application;

[0018] Figure 3 is a control principle diagram according to the embodiment of the present application; DETAILED DESCRIPTION

[0019] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0020] It is also important to note that the terms used herein are not intended to limit the particular embodiments of the present application disclosed in this specification. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. In addition, it is also to be understood that the use of the terms "include" and / or "comprise", when used in this specification, refers to the presence of a feature, step, operation, device, component and / or combinations thereof.

[0021] As shown in Figures 2-3 A system for reducing the loss of molten metal in a gas melting furnace, the gas melting furnace comprising a circular furnace body D and at least one set of combustion devices, each set of combustion devices comprising a regenerative burner 1, a regenerative chamber A, a gas pipe, a low-nitrogen burner 2 is provided beside the outlet of the regenerative burner, the regenerative burner 1 produces a straight jet flame, and the low-nitrogen burner 2 produces a diffuse flame, a main gas inlet pipe is connected between the gas pipe and the regenerative burner, a secondary gas inlet pipe is connected between the gas pipe and the low-nitrogen burner, a first gas solenoid valve c is provided on the gas pipe, a second gas solenoid valve b is provided on the main gas inlet pipe, and a third gas solenoid valve d is provided on the secondary gas inlet pipe. The third gas solenoid valve d is used to control the combustion of the diffuse flame, and the second gas solenoid valve b is used to control the combustion of the straight jet flame. When the temperature in the furnace is greater than 900 degrees, the combustion of the straight jet flame in the furnace is changed to the combustion of the diffuse flame by changing the combustion mode, so that the flame is evenly distributed, thereby improving the rapid melting of metal waste in the furnace, reducing the oxidation of metal materials, and reducing the content of nitrogen oxides emissions. Therefore, whether from the energy saving effect and the product quality has been significantly improved compared with before, the production cost is reduced, and good economic and social benefits are achieved. The natural gas introduced directly into the furnace by the regenerative burner and the low-nitrogen burner forms a flame, the combustion-supporting wind is introduced through the regenerative chamber, the hot wind flowing through the regenerative balls in the regenerative chamber supplies the fuel in the furnace for combustion, thereby improving the combustion efficiency.

[0022] In this embodiment, a manual ball valve f and a gas pressure sensor a are respectively provided on the gas pipe, the main gas inlet pipe and the secondary gas inlet pipe. When the regenerative burner is working, if the gas pipe pressure is less than or equal to 0.1 MPa, an alarm is given and the gas main valve is quickly cut off. When the low-nitrogen burner is working, if the gas pipe pressure is less than or equal to 0.1 MPa, an alarm is given and the gas main valve is quickly cut off. The manual ball valve f is convenient for installation and disassembly and can independently cut off the fuel.

[0023] When the regenerative burner is working, the first gas cut-off valve c is opened, the second gas circulation valve b is opened, the air introduced by the air blower is mixed and then sprayed through the regenerative burner. At the same time, the third gas circulation valve d is closed and is interlocked with the second gas circulation valve b to ensure that the gas circulation valves b and d cannot be opened at the same time.

[0024] When the low-nitrogen burner is working, the first gas cut-off valve c is opened, the third gas circulation valve d is opened, the air introduced by the air blower enters the regenerative chamber and is introduced into the furnace from the regenerative burner to assist combustion of the fuel, at this time, the hot air supply system is separated from the fuel supply system.

[0025] In the embodiment, the circular furnace body D is provided with a flame high-temperature camera h above the regenerative burner to detect the flame state of the burner, the flame high-temperature camera h is interlocked with the first gas cut-off valve c, and once the flame state in the furnace is not detected, the combustion controller will immediately cut off the first gas cut-off valve c to ensure the safety of the equipment.

[0026] In the embodiment, the circular furnace body is provided with a first temperature sensor e at the top and a second temperature sensor (not shown in the figure) at the side; all the gas solenoid valves and the flame high-temperature camera are electrically connected with the combustion controller, the gas pressure sensor, the temperature sensor and the combustion controller are electrically connected with the PLC controller, and the PLC controller is further connected with an alarm. The temperature difference between the top and the inside of the furnace is compared to further confirm the temperature difference in the furnace, and the low-nitrogen burner can only be started when the deviation is within ±2 degrees, to ensure the stability of the diffusion flame combustion system and the reliable safety of the combustion in the furnace.

[0027] In the embodiment, the combustion device is four groups, two groups of the combustion device form a set of combustion system, and the two groups of the combustion device of the combustion system are arranged on opposite sides of the circular furnace body, and the four groups of the combustion device form two sets of the combustion system. The two groups of the combustion device of the same set of the combustion system are switched according to time. When the left regenerative chamber is in the air blowing state, the left burner is ignited and is in the combustion state, at this time, the right regenerative chamber is in the air induction state, and the right burner stops working, and the discharged flue gas is used to preheat the regenerative balls. After the combustion time is reached, the right side is switched to work, at this time, the right regenerative chamber is in the air blowing state, the right burner starts to burn, the left burner stops working, the left regenerative chamber is in the air induction state, and the discharged flue gas is used to preheat the regenerative balls.

[0028] Another technical scheme of the present application is a control method of the system for reducing the burning loss of molten metal of a gas melting furnace, the regenerative burner is started to perform direct injection combustion first; when the temperature in the furnace is greater than 900 degrees, the low-nitrogen burner is started to perform diffusion combustion, and the regenerative burner is closed at the same time; when the temperature in the furnace is less than 900 degrees, the regenerative burner is started again to perform direct injection combustion, and the low-nitrogen burner is closed at the same time.

[0029] In the embodiment, the flame high-temperature camera monitors the flame state in the furnace in real time, once the flame signal loss or the camera failure is detected, the combustion controller detects the flame failure, immediately cuts off the gas, and feeds back the signal to the PLC controller to close the combustion device, namely, to cut off the first gas cut-off valve c.

[0030] In the embodiment, when the gas pressure sensor senses that the gas pressure is less than or equal to 0.1 MPa, an alarm is given and the gas is quickly cut off.

[0031] In the embodiment, before the low-nitrogen burner is started, it is ensured that the temperature difference detected by the first temperature sensor and the second temperature sensor is not more than ±2 degrees, which is used as a condition for judging the start of the low-nitrogen burner; the condition for starting the low-nitrogen burner is increased, that is, two conditions need to be met for starting the low-nitrogen burner: when the temperature in the furnace is greater than 900 degrees, and the temperature difference detected by the first temperature sensor and the second temperature sensor in the furnace is not more than ±2 degrees.

[0032] In the embodiment, two groups of combustion devices of the same set of combustion system are switched according to time.

[0033] Any of the technical solutions disclosed in the above embodiments, unless otherwise stated, if a numerical range is disclosed, the disclosed numerical range is a preferred numerical range, and any person skilled in the art should understand that the preferred numerical range is only one of the many implementable values with more obvious technical effects or representative values. Because there are too many values, it is impossible to enumerate them all, so the present application discloses some values to illustrate the technical solutions of the present application, and the above-mentioned values should not constitute a limitation on the protection scope of the present application.

[0034] If the present application discloses or involves parts or structural members that are fixedly connected to each other, unless otherwise stated, the fixed connection can be understood as being detachably fixedly connected (for example, connected using bolts or screws), or as being fixedly connected without being detachable (for example, riveted, welded), and of course, the fixed connection can also be replaced by an integral structure (for example, manufactured by integral molding process, except for obvious cases where integral molding process cannot be used).

[0035] In addition, the terms used to represent the positional relationship or shape in any of the technical solutions disclosed in the above embodiments, unless otherwise stated, include states or shapes that are approximate, similar or close to them.

[0036] Any of the components provided by the present application can be assembled from multiple individual components, or can be a single component manufactured by integral molding process.

[0037] The above merely describes preferred embodiments of the present application, but is not intended to limit the present application to other forms, and any person skilled in the art can make changes or modifications to the above disclosed technical contents into equivalent embodiments with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiments without departing from the technical solution content of the present application, and according to the technical essence of the present application, still belongs to the protection scope of the technical solution of the present application.

Claims

1. A system for reducing burnout of molten metal in a gas-fired melting furnace, the gas-fired melting furnace comprising a circular furnace body and at least one set of combustion devices, each set of combustion devices comprising a regenerative burner, a regenerative chamber, and a gas pipe, characterized in that: A low-nitrogen burner is provided beside the outlet of the regenerative burner, a main air intake pipe is connected between the gas pipe and the regenerative burner, a secondary air intake pipe is connected between the gas pipe and the low-nitrogen burner, a first gas solenoid valve is provided on the gas pipe, a second gas solenoid valve is provided on the main air intake pipe, and a third gas solenoid valve is provided on the secondary air intake pipe.

2. The system for reducing burnout of molten metal in a gas-fired melting furnace according to claim 1, characterized in that: The gas pipe, the main air intake pipe and the secondary air intake pipe are respectively provided with a manual ball valve and a gas pressure sensor.

3. The system for reducing molten metal burnout in a gas-fired melting furnace according to claim 2, characterized in that: A flame high temperature camera is provided on the peripheral wall of the circular furnace body above the regenerative burner.

4. The system for reducing burnout of molten metal in a gas-fired melting furnace according to claim 3, characterized in that: A first temperature sensor is provided on the top of the circular furnace body, and a second temperature sensor is provided on the side of the circular furnace body; all gas solenoid valves and flame high-temperature cameras are electrically connected to the combustion controller, and the gas pressure sensor, temperature sensor and combustion controller are electrically connected to the PLC controller.

5. The system for reducing burnout of molten metal in a gas-fired melting furnace according to claim 4, characterized in that: There are four groups of combustion devices, two groups of combustion devices form a combustion system, and the two groups of combustion devices of the combustion system are arranged on opposite sides of the circular furnace body.

6. A control method for a system for reducing molten metal burnout in a gas-fired melting furnace according to claim 5, characterized in that: First start the regenerative burner for direct injection combustion; when the temperature in the furnace is greater than 900 degrees, start the low-nitrogen burner for diffuse combustion, and at the same time close the regenerative burner; when the temperature in the furnace is less than 900 degrees, start the regenerative burner again for direct injection combustion, and at the same time close the low-nitrogen burner.

7. The control method of the system for reducing the burnout of molten metal in a gas-fired melting furnace according to claim 6, characterized in that: The flame high-temperature camera monitors the flame status in the furnace in real time. Once the flame detection signal is lost or the camera fails, the combustion controller fails to detect the flame, immediately cuts off the gas, and feeds the signal back to the PLC controller to shut down the combustion device.

8. The control method of the system for reducing the burnout of molten metal in a gas-fired melting furnace according to claim 6, characterized in that: When the gas pressure sensor senses that the gas pressure is ≤0.1MPa, it will alarm and quickly cut off the gas.

9. The control method of the system for reducing the burnout of molten metal in a gas-fired melting furnace according to claim 6, characterized in that: Before the low nitrogen burner is turned on, ensure that the temperature difference in the furnace detected by the first temperature sensor and the second temperature sensor does not exceed ±2 degrees, which is used as the condition for judging the opening of the low nitrogen burner.

10. The control method of the system for reducing the burnout of molten metal in a gas-fired melting furnace according to claim 6, characterized in that: The two sets of combustion devices in the same combustion system work alternately according to time.

Images