A kind of aluminum ash electric arc furnace flue gas treatment device

Abstract

The utility model relates to the field of smelting equipment, and discloses a fume treatment device for an aluminum ash electric arc furnace, comprising a furnace cover and a secondary combustion chamber, wherein a smoke exhaust port is provided on the furnace cover, and a smoke inlet and a smoke outlet are respectively provided at two ends of the secondary combustion chamber, the smoke inlet of the secondary combustion chamber is connected with the smoke exhaust port of the furnace cover through a smoke exhaust pipe, and the smoke outlet of the secondary combustion chamber is connected with the outside through the smoke exhaust pipe, the smoke exhaust pipes at the two ends are vertically arranged, and the secondary combustion chamber and the smoke exhaust pipes at the two ends are U-shaped; the secondary combustion chamber is arranged outside the furnace, and a burner for igniting the fume is provided at the smoke inlet of the secondary combustion chamber; the technical problem that the existing electric arc furnace has local hypoxia during the smelting process, resulting in excessive carbon monoxide in the tail gas is solved.

Description

Technical Field

[0001] The utility model relates to the field of smelting equipment, in particular to a fume treatment device for an aluminum ash electric arc furnace. Background Art

[0002] Electric arc furnaces are industrial furnaces that use metal electrodes or non-metallic electrodes to generate electric arc heating. In the process of producing calcium aluminate from aluminum ash, calcium carbonate and calcium oxide, the aluminum ash contains impurity carbon, which causes local oxygen deficiency during the arc furnace smelting process, resulting in incomplete combustion and excessive carbon monoxide in the exhaust gas, which does not meet environmental protection requirements.

[0003] However, if air is introduced into the furnace, a large amount of nitrogen and other inert gases will be introduced together with oxygen. The furnace, which was originally only partially deficient in oxygen, will greatly increase the oxidation and consumption of the electrode due to the entry of a large amount of oxygen. The entry of other gases besides oxygen into the electric furnace will increase the operating load of the dust removal system. After nitrogen enters the furnace, it will crack under the high-temperature electric arc, affecting the quality of the final product. Although the emission of carbon monoxide is reduced, the reduction in the quality of the finished product and the large amount of electrode oxidation consumption are still contrary to environmental protection. Utility Model Content

[0004] The utility model aims to provide a fume treatment device for an aluminum ash electric arc furnace, so as to solve the technical problem that the existing electric arc furnace has local oxygen deficiency during the smelting process, resulting in excessive carbon monoxide in the tail gas.

[0005] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a flue gas treatment device for an aluminum ash electric arc furnace, comprising a furnace cover and a secondary combustion chamber, the furnace cover is provided with a smoke exhaust port, and the two ends of the secondary combustion chamber are respectively provided with a smoke inlet and a smoke outlet, the smoke inlet of the secondary combustion chamber is connected with the smoke exhaust port of the furnace cover through a smoke exhaust pipe, the smoke outlet of the secondary combustion chamber is connected with the outside through the smoke exhaust pipe, the smoke exhaust pipes at both ends are vertically arranged, and the secondary combustion chamber and the smoke exhaust pipes at both ends are U-shaped; the secondary combustion chamber is arranged outside the furnace, and a burner for igniting flue gas is provided at the smoke inlet in the secondary combustion chamber.

[0006] The principle and advantages of this scheme are as follows: the flue gas in the electric arc furnace body enters the exhaust pipe from the exhaust port on the furnace cover, first vertically downward for a distance to enter the secondary combustion chamber, the flue gas is ignited by the burner at the smoke inlet of the secondary combustion chamber, carbon monoxide burns to form carbon dioxide, the flue gas moves horizontally along the secondary combustion chamber to the smoke outlet, and the burned flue gas finally goes up along the exhaust pipe and finally overflows from the upper end of the exhaust port;

[0007] The arc furnace structure can perform secondary combustion on the flue gas to avoid excessive carbon monoxide in the final exhaust gas. Furthermore, according to the present invention, the smoke exhaust pipe and the combustion chamber are U-shaped, and the arc furnace continuously discharges smoke to the outside during high-temperature operation. This structure can prevent outside air from entering the arc furnace through the pipeline, thereby avoiding increasing the workload of the arc furnace. The flame of the burner comes from the pre-mixed fuel and oxygen, and can accurately control the combustion conditions in the combustion chamber, while ensuring the complete conversion of carbon monoxide, it also avoids affecting the normal operation of the arc furnace. The smoke moves vertically in the smoke exhaust pipe, which can precipitate some solid particles in the smoke and reduce the pollution of the smoke to the outside world.

[0008] As an improvement, the burner ejects flame from the smoke inlet toward the smoke outlet, the smoke inlet of the secondary combustion chamber faces the flame core of the burner, and the angle formed by the smoke inflow direction at the smoke inlet of the secondary combustion chamber and the flame ejection direction of the burner is greater than 90° and less than 180°

[0009] The beneficial effects of this improvement are: facing the flame core allows the gas to directly contact the highest temperature of the flame and thus fully burn, thereby improving the efficiency of converting carbon monoxide into carbon dioxide; because when the flue gas enters the secondary combustion chamber, the flame will be affected by obvious wind force, thereby changing the original direction and causing the flame to deflect, so that a gap is formed between the side wall of the secondary combustion chamber at the air inlet and the flame, so that the flue gas flows directly to the smoke outlet without being burned, causing smoke to escape. The angle makes the direction of the flue gas flowing into the secondary combustion chamber at the smoke inlet slightly offset and tangent to the flame ejection direction, ensuring that the flue gas can be completely burned.

[0010] As an improvement, the chamber wall of the secondary combustion chamber includes an inner chamber wall and an outer chamber wall, the inner chamber wall is refractory bricks, and the outer chamber wall is refractory wool.

[0011] The beneficial effects of this improvement are: the refractory bricks are resistant to high temperatures and provide strong support for the secondary combustion chamber. The refractory cotton has an insulating effect on the secondary combustion chamber, while also preventing the outer surface temperature of the secondary combustion chamber from being too high, thereby playing a safety protection role and ensuring that the combustion furnace does not cause harm to the surrounding environment and personnel during operation.

[0012] As an improvement, the smoke exhaust pipe includes a first smoke exhaust pipe for connecting the smoke inlet and a second smoke exhaust pipe for connecting the smoke outlet. A connecting pipe for connecting the two ends is provided between the first smoke exhaust pipe and the furnace cover. The connecting pipe is a right-angle bend. The vertical end of the connecting pipe is connected to the furnace cover, and the horizontal end of the connecting pipe is connected to the first smoke exhaust pipe.

[0013] The beneficial effect of this improvement is that increasing the turning points of the flue gas flow path can slow down the flue gas flow rate to facilitate the subsequent control of complete combustion of the flue gas, and the setting of multiple corner paths also reduces the difficulty of oxygen outside the arc furnace overflowing back into the arc furnace to increase the workload.

[0014] As an improvement, the diameter of the vertical port of the connecting pipe gradually decreases from the outside to the inside.

[0015] The beneficial effect of this improvement is that when the flue gas enters the connecting pipe from the electric arc furnace, the structure can reduce the gas pressure, slow down the flow rate, and prevent the gas flow from overflowing.

[0016] As an improvement, a coke clearing port is provided at the bottom of the first smoke exhaust pipe, and a coke clearing port is provided in the second combustion chamber below the smoke outlet.

[0017] The beneficial effect of this improvement is to remove the sediment in the vertical movement of the flue gas to avoid clogging of the pipeline.

[0018] As an improvement, a thermocouple is provided in the secondary combustion chamber at the smoke outlet, and a thermocouple is provided in the horizontal section of the connecting pipe.

[0019] The beneficial effects of this improvement are: the temperature of the flue gas flowing out of the arc furnace body can be monitored in real time, and the flue gas volume can be determined to adjust the fuel supply to the burner, and the temperature of the flue gas when it leaves the secondary combustion chamber can be measured, which helps to evaluate the combustion efficiency and emission quality, and can also detect whether the equipment has signs of overheating damage to prevent potential safety hazards.

[0020] As an improvement, an observation window is provided in the secondary combustion chamber at a position directly opposite to the smoke outlet.

[0021] The beneficial effect of this improvement is that it is convenient for the staff to observe the smoke combustion conditions and adjust the burner operating parameters.

[0022] As an improvement, the secondary combustion chamber is a long and narrow main body, and the cross section of the secondary combustion chamber is a rectangular bottom and an arc-shaped top structure.

[0023] The beneficial effects of this improvement are: providing a sufficiently long space distance for smoke combustion, the rectangular bottom design can provide good support and stability, ensuring that the secondary combustion chamber will not deform or displace during the combustion process, and the curved top can effectively disperse the top pressure, reduce stress concentration, and improve the overall bearing capacity of the secondary combustion chamber.

[0024] As an improvement, the angle formed by the smoke inflow direction at the smoke inlet of the secondary combustion chamber and the flame ejection direction of the burner is 93°

[0025] The beneficial effect of this improvement is that after repeated tests, it was found that when the angle formed by the smoke inflow direction at the smoke inlet of the secondary combustion chamber and the flame ejection direction of the burner is 93°, the smoke can be ignited most efficiently to avoid the escape of unburned smoke. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1It is the front view of the embodiment of the utility model.

[0027] Figure 2 It is a right side view of an embodiment of the utility model.

[0028] Figure 3 It is a top view of an embodiment of the utility model.

[0029] Figure 4 It is a structural schematic diagram of the cross section of the secondary combustion chamber. DETAILED DESCRIPTION

[0030] The following is further described in detail through specific implementation methods:

[0031] The figure marks in the drawings of the specification include: furnace cover 1, smoke exhaust port 2, connecting pipe 3, first smoke exhaust pipe 4, second smoke exhaust pipe 5, secondary combustion chamber 6, burner 7, smoke inlet 8, smoke outlet 9, refractory bricks 10, refractory wool 11, coke cleaning port 12, thermocouple 13 and observation window 14.

[0032] The embodiment is basically as shown in the attached Figure 1 , Attachment Figure 2 and attached Figure 3 As shown, a flue gas treatment device for an aluminum ash electric arc furnace includes an electric arc furnace body and a secondary combustion chamber 6. A smoke exhaust port 2 is provided on a furnace cover 1 of the electric arc furnace body. The smoke exhaust port 2 is located next to the electrode on the furnace cover 1. The secondary combustion chamber 6 is arranged outside the electric arc furnace body. The electric arc furnace body and the secondary combustion chamber 6 are connected to each other through a connecting pipe 3 and a first smoke exhaust pipe 4 in turn. The connecting pipe 3 is a right-angle bend pipe. The vertical end of the connecting pipe 3 is connected to the furnace cover 1, so that the smoke in the electric arc furnace body moves upward from the smoke exhaust port 2 along the vertical section of the connecting pipe 3. The horizontal end of the connecting pipe 3 is connected to the first smoke exhaust pipe 4, so that the smoke in the connecting pipe 3 moves horizontally by one end to the upper end of the first smoke exhaust pipe 4. The diameter of the vertical port of the connecting pipe 3 gradually decreases from the outside to the inside, so that the high-temperature gas in the electric arc furnace body enters the connecting pipe 3 to reduce the gas pressure and slow down the flow rate.

[0033] A smoke inlet 8 and a smoke outlet are respectively provided at both ends of the second combustion chamber 6. The first smoke exhaust pipe 4 is connected to the second combustion chamber 6 at the smoke inlet 8. A second smoke exhaust pipe 5 is provided at the smoke outlet of the second combustion chamber 6. The second smoke exhaust pipe 5 connects the second combustion chamber 6 with the outside world. The smoke exhaust pipes at both ends are vertically arranged. The first smoke exhaust pipe 4 guides the smoke to move downward and flow into the second combustion chamber 6, and the second smoke exhaust pipe 5 guides the smoke to move upward and flow out to the outside world. The second combustion chamber 6 and the first smoke exhaust pipe 4 and the second smoke exhaust pipe 5 at the connecting end are U-shaped. A burner 7 for igniting smoke is provided at the smoke inlet 8 in the second combustion chamber 6.

[0034] The burner 7 is a natural gas burner 7. Natural gas and air are mixed in a certain proportion in the natural gas burner 7. The mixed gas enters the ignition device. After ignition, the mixed gas burns to generate flames, ignites the carbon monoxide in the flue gas, and during the secondary combustion of the flue gas, the excess carbon monoxide in the flue gas is supplemented and burned in the secondary combustion chamber 6, and converted into carbon dioxide and water. The burner 7 sprays flames from the smoke inlet 8 toward the smoke outlet, and the smoke inlet 8 of the secondary combustion chamber 6 faces the flame core of the burner 7.

[0035] When the smoke enters the secondary combustion chamber 6, the flame will be affected by obvious wind force, thereby changing the original direction and causing the flame to deflect, so that a gap is formed between the side wall of the secondary combustion chamber 6 at the air inlet and the flame, so that the smoke flows directly to the smoke outlet without being burned, causing smoke escape. The angle formed by the smoke inflow direction at the smoke inlet 8 of the secondary combustion chamber 6 and the flame ejection direction of the burner 7 is greater than 90° and less than 180°, so that the smoke flow direction flowing into the secondary combustion chamber 6 at the smoke inlet 8 is slightly offset and tangent to the flame ejection direction. In this embodiment, after repeated experiments, it was found that when the angle formed by the smoke inflow direction at the smoke inlet 8 of the secondary combustion chamber 6 and the flame ejection direction of the burner 7 is 93°, the smoke can be ignited most efficiently to avoid the escape of unburned smoke.

[0036] As attached Figure 4 As shown, the chamber wall of the secondary combustion chamber 6 includes an inner chamber wall and an outer chamber wall. The inner chamber wall is a refractory brick 10, and the outer chamber wall is a refractory wool 11. The refractory brick 10 can be specifically a first-class high-alumina brick, which is resistant to high temperatures and provides a strong supporting force for the secondary combustion chamber 6. The refractory wool 11 can be specifically an aluminum silicate fiber blanket, which has a heat-insulating effect on the secondary combustion chamber 6 and also prevents the outer surface temperature of the secondary combustion chamber 6 from being too high, thereby playing a safety protection role and ensuring that the combustion furnace does not cause harm to the surrounding environment and personnel during operation.

[0037] The secondary combustion chamber 6 is in the shape of an elongated strip, and the cross section of the secondary combustion chamber 6 is a rectangular bottom and an arc-shaped top. The rectangular bottom design can provide good support and stability, ensuring that the secondary combustion chamber 6 will not deform or shift during the combustion process. At the same time, the arc-shaped top can effectively disperse the top pressure, reduce stress concentration, and improve the overall load-bearing capacity of the secondary combustion chamber 6. The elongated secondary combustion chamber 6 can provide a longer combustion path, allowing the fuel to be more fully burned in the combustion chamber. The arc-shaped top design is conducive to the uniform distribution and circulation of heat, further improving the combustion efficiency.

[0038] The smoke inlet 8 is located on the vertical side wall of the secondary combustion chamber 6 to prevent the flame from directly igniting the gas in the first smoke exhaust pipe 4 and affecting the normal operation of the electric arc furnace body; the smoke outlet is located at the top of the secondary combustion chamber 6. During the vertical movement of the smoke, the solid particles in the smoke will partially settle downward due to gravity. A decoking port 12 is provided at the bottom of the first smoke exhaust pipe 4, and a decoking port 12 is provided in the secondary combustion chamber 6 below the smoke outlet. The staff can regularly open the decoking port 12 to remove the precipitated dust.

[0039] A thermocouple 13 is provided at the smoke outlet in the secondary combustion chamber 6, and a thermocouple 13 is provided in the horizontal section of the connecting pipe 3; the thermocouple 13 in the connecting pipe 3 can monitor the temperature of the flue gas flowing out of the arc furnace body in real time, and then determine the amount of flue gas to adjust the fuel supply of the burner 7; the thermocouple 13 at the smoke outlet can measure the temperature of the flue gas when it leaves the secondary combustion chamber 6, which helps to evaluate the combustion efficiency and emission quality. A higher outlet temperature may mean incomplete combustion, requiring further adjustment or maintenance. The thermocouples 13 at the two locations can also detect whether there are signs of overheating damage to the equipment to prevent potential safety hazards.

[0040] An observation window 14 is provided in the second combustion chamber 6 at the position opposite to the smoke outlet, and the staff can observe the burning flame from this window. The length ratio of the smoke inlet 8 to the fire outlet and the fire outlet to the smoke outlet in the second combustion chamber 6 is 1:4, providing a sufficiently long space distance for combustion.

[0041] The specific implementation process is as follows:

[0042] The carbon monoxide gas generated in the arc furnace body due to insufficient oxygen cannot be fully burned. It is discharged from the arc furnace body through the connecting pipe 3 along with the flue gas, and descends along the first smoke exhaust pipe 4 into the secondary combustion chamber 6. During the downward process of the smoke, some solid particles are precipitated and remain at the bottom of the first smoke exhaust pipe 4. When the smoke reaches the smoke inlet 8, the flame ejected from the burner 7 ignites the carbon monoxide in the flue gas and converts it into carbon dioxide. The flue gas moves horizontally in the secondary combustion chamber 6, completes combustion between the smoke inlet 8 and the smoke outlet, and enters the second smoke exhaust pipe 5 at the smoke outlet to move upward. During the upward movement, some solid particles in the smoke are precipitated again and are finally discharged to the outside or connected to the next process, thereby making the smoke discharged from the arc furnace body cleaner and more environmentally friendly.

[0043] The above is only an embodiment of the utility model, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the utility model, several deformations and improvements can be made, which should also be regarded as the protection scope of the utility model, and these will not affect the effect of the implementation of the utility model and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. An aluminum ash arc furnace flue gas treatment device, characterized in that: It includes a furnace cover and a secondary combustion chamber, the furnace cover is provided with a smoke exhaust port, and both ends of the secondary combustion chamber are respectively provided with a smoke inlet and a smoke outlet, the smoke inlet of the secondary combustion chamber is connected with the smoke exhaust port of the furnace cover through a smoke exhaust pipe, the smoke outlet of the secondary combustion chamber is connected with the outside through the smoke exhaust pipe, the smoke exhaust pipes at both ends are vertically arranged, and the secondary combustion chamber and the smoke exhaust pipes at both ends are U-shaped; the secondary combustion chamber is arranged outside the furnace, and a burner for igniting smoke is provided at the smoke inlet in the secondary combustion chamber.

2. The aluminum ash arc furnace flue gas treatment device according to claim 1, characterized in that: The burner sprays flame from the smoke inlet toward the smoke outlet, the smoke inlet of the secondary combustion chamber faces the flame core of the burner, and the angle formed by the smoke inflow direction at the smoke inlet of the secondary combustion chamber and the flame spraying direction of the burner is greater than 90° and less than 180°.

3. The aluminum ash arc furnace fume treatment device according to claim 2 is characterized in that: The chamber wall of the secondary combustion chamber comprises an inner chamber wall and an outer chamber wall, the inner chamber wall is refractory bricks, and the outer chamber wall is refractory wool.

4. The aluminum ash arc furnace fume treatment device according to claim 3 is characterized in that: The smoke exhaust pipe includes a first smoke exhaust pipe for connecting the smoke inlet and a second smoke exhaust pipe for connecting the smoke outlet. A connecting pipe for connecting the two ends is provided between the first smoke exhaust pipe and the furnace cover. The connecting pipe is a right-angle bend. The vertical end of the connecting pipe is connected to the furnace cover, and the horizontal end of the connecting pipe is connected to the first smoke exhaust pipe.

5. The aluminum ash arc furnace fume treatment device according to claim 4 is characterized in that: The diameter of the vertical port of the connecting pipe gradually decreases from outside to inside.

6. The aluminum ash electric arc furnace fume treatment device according to claim 5, characterized in that: A coke clearing port is provided at the bottom of the first smoke exhaust pipe, and a coke clearing port is provided in the second combustion chamber below the smoke outlet.

7. The aluminum ash electric arc furnace fume treatment device according to claim 6, characterized in that: A thermocouple is provided at the smoke outlet in the secondary combustion chamber, and a thermocouple is provided in the horizontal section of the connecting pipe.

8. The aluminum ash arc furnace fume treatment device according to claim 7, characterized in that: An observation window is arranged in the second combustion chamber at a position directly opposite to the smoke outlet.

9. The aluminum ash arc furnace fume treatment device according to claim 8, characterized in that: The secondary combustion chamber is a long and narrow main body, and the cross section of the secondary combustion chamber is a rectangular bottom and an arc-shaped top structure.

10. The aluminum ash electric arc furnace fume treatment device according to claim 9, characterized in that: The angle formed by the smoke inflow direction at the smoke inlet of the secondary combustion chamber and the flame ejection direction of the burner is 93°.

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