Continuous refining furnace waste heat recovery method

Abstract

The invention relates to a waste heat recovery method for a continuous refining furnace, which adopts a waste heat recovery system for waste heat recovery, the waste heat recovery system comprises at least one bypass flue, inlets and outlets of all the bypass flues are communicated with a main flue of the continuous refining furnace, and a baking chamber is arranged in the middle of each bypass flue. The baking chambers are used for placing objects to be heated, a smoke inlet and a smoke outlet of each baking chamber are respectively provided with a valve, the main flue is provided with a smoke adjusting valve, the starting end and the tail end of the main flue are respectively provided with a temperature measuring sensor A, and each baking chamber is internally provided with a temperature measuring sensor B; high-temperature flue gas is introduced through the bypass flue and the baking chamber to heat an object to be heated, so that waste heat recovery is achieved; after being cooled, the flue gas is introduced into a spray cooling tower, and dioxin is prevented from being generated by controlling the time of the flue gas flowing through the baking chamber.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of copper smelting production, in particular to a continuous refining furnace waste heat recovery method. BACKGROUND

[0002] When the continuous refining furnace smelts scrap copper raw materials, the flue gas temperature can reach 1200℃~1350℃. At present, the flue gas generated during the production of the continuous refining furnace is sent into a spray cooling tower through the main flue at the tail of the furnace, and after the flue gas is cooled by the spray cooling tower, the flue gas is sent to a bag dust collector for dust removal and then to a tail gas desulfurization system for purification. The reason why the flue gas treatment system of the continuous refining furnace selects the spray cooling tower to cool the flue gas is to meet the environmental protection requirements. The document "Flue gas cooling design and application of continuous refining furnace" introduces that the spray cooling tower can reduce the flue gas from 800~950℃ to 300~350℃ in only 1.26s, so that the flue gas quickly passes through the temperature range of dioxin generation, thereby effectively preventing the generation of dioxin.

[0003] This set of tail gas treatment process does not utilize the flue gas waste heat, resulting in energy waste, so it is necessary to design a waste heat recovery process to recover and utilize the originally wasted flue gas waste heat. SUMMARY

[0004] In order to solve the above technical problems, the present application provides a continuous refining furnace waste heat recovery method.

[0005] The specific scheme of the present application is as follows: a continuous refining furnace waste heat recovery method, which adopts a waste heat recovery system for waste heat recovery, the waste heat recovery system comprises at least one bypass flue, the inlet and outlet of all the bypass flues are communicated with the main flue of the continuous refining furnace, the middle part of each bypass flue is provided with a baking chamber, the baking chamber is used for placing a to-be-heated object, the smoke inlet and smoke outlet of each baking chamber are provided with valves, a smoke adjusting valve is arranged on the main flue, a temperature measuring sensor A is arranged at the starting end and the end of the main flue, and a temperature measuring sensor B is arranged in each baking chamber.

[0006] S1, during the production of the continuous refining furnace, the inlet valve and the outlet valve of the baking chamber are closed in sequence, and then the to-be-heated object is placed in the corresponding baking chamber;

[0007] S2, when the flue gas temperature of the continuous refining furnace is higher than 700℃, the inlet valve and the outlet valve of the baking chamber are opened, the opening degree of the smoke adjusting valve is adjusted, part of the flue gas in the main flue is introduced into the baking chamber through the bypass flue to heat the to-be-heated object, and the cooled flue gas is introduced back into the main flue through the bypass flue;

[0008] S3, adjust the opening of the smoke regulating valve, the inlet valve and the outlet valve, so that the flue gas temperature at the end of the main flue is always higher than 650℃-700℃; control the gradual increase of the flue gas temperature in the baking chamber and maintain it in the range of 80℃-600℃;

[0009] S4, when the flue gas temperature of the main flue is lower than 650℃-700℃, the inlet valve and the outlet valve of the baking chamber are closed in turn, the smoke regulating valve is fully opened, and the cooling of the flue gas is stopped.

[0010] S5, when the heating time of the to-be-heated object reaches the requirement, first close the inlet valve and the outlet valve of the baking chamber in turn, then fully open the smoke regulating valve, and finally take out the to-be-heated object.

[0011] Further, when the number of bypass flues exceeds 1, the bypass flues are connected in parallel and all communicate with the main flue.

[0012] Further, the flow area of each bypass flue is 30%-100% of the main flue.

[0013] Further, each bypass flue is provided with at least one baking chamber, and the baking chambers are arranged in series or parallel.

[0014] Further, the length of each baking chamber is calculated according to the flue gas flow rate and flue gas flow time, and when there is only one baking chamber on a bypass flue, the time for flue gas to flow through the baking chamber is ensured to be less than 3 seconds, and when multiple baking chambers are arranged on a bypass flue, the total time for flue gas to flow through all the baking chambers is ensured to be less than 5 seconds.

[0015] Further, when the baking chambers are arranged in parallel, the different baking chamber temperatures are divided into 2-6 temperature sections, and the baking time for each temperature section is 0.2-4h.

[0016] Further, the baking chamber is provided with a hanging bag, and the hanging bag is used to place the to-be-heated object. The structure of the hanging bag includes a general hanging bag and a customized hanging bag. The general hanging bag is suitable for the overall heating of the to-be-heated object, and the customized hanging bag is used for partial surface heating of the to-be-heated object.

[0017] Further, the top of each baking chamber is provided with a cover plate, the top of the cover plate is provided with a lifting ring, and the bottom surface of the cover plate is provided with a heat preservation layer.

[0018] Compared with the prior art, the present application has the following beneficial effects: 1. The flue gas waste heat of the continuous refining furnace is recovered, the heated objects are heated by the flue gas after the flue gas enters the baking chamber, thereby recovering the flue gas waste heat and saving energy cost; meanwhile, the effect of the spray cooling tower on the prevention of dioxin in the flue gas is not affected; 2. When the baking chamber adopts the combined configuration in the parallel mode, the heated objects with different heating requirements can be heated and baked at the same time, the baking efficiency is improved, the production organization is more flexible, the flue gas cooling capacity is stronger, and the flue gas waste heat is recovered to a greater extent. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a waste heat recovery system schematic diagram of the present application embodiment one;

[0020] Figure 2 is a waste heat recovery system schematic diagram of the present application embodiment two;

[0021] Figure 3 is a waste heat recovery system schematic diagram of the present application embodiment three;

[0022] Figure 4 is the A-A sectional view of Figure 1 ;

[0023] Figure 5 is the B-B sectional view of Figure 2 ;

[0024] In the figure: 1, continuous refining furnace; 2, main flue; 3, smoke adjusting valve; 4, bypass flue; 5, inlet valve; 6, baking chamber; 7, customized hanging bag; 8, outlet valve; 9, temperature measuring sensor B; 10, temperature measuring sensor A; 11, spray cooling tower; 12, general hanging bag; 13, cover plate. DETAILED DESCRIPTION

[0025] Embodiment one

[0026] Referring to Figure 1 , Figure 4The embodiment provides a continuous refining furnace 1 waste heat recovery method, waste heat is recovered by adopting a waste heat recovery system, the waste heat recovery system comprises a bypass flue 4 which is parallel to a main flue 2, the inlet and outlet of the bypass flue 4 are communicated with the main flue 2 of the continuous refining furnace 1, a baking chamber 6 is arranged in the middle part of the bypass flue 4, the baking chamber 6 is used for placing heated objects, the smoke inlet and smoke outlet of the baking chamber 6 are provided with valves, a smoke adjusting valve 3 is arranged on the main flue 2, a temperature measuring sensor A10 is arranged at the starting end and the end of the main flue 2 respectively, a temperature measuring sensor B9 is arranged in the baking chamber 6, the end of the flue is connected to a spray cooling tower 11, the temperature measuring sensor A10 and the temperature measuring sensor B9 are both thermocouples; the waste heat recovery method comprises the following steps: S1, when the continuous refining furnace 1 is produced, the inlet valve 5 and the outlet valve 8 of the baking chamber 6 are closed in turn, then the heated objects are placed in the corresponding baking chamber 6; S2, when the flue gas temperature of the continuous refining furnace 1 is higher than 700 DEG C, the inlet valve 5 and the outlet valve 8 of the baking chamber 6 are opened, the opening degree of the smoke adjusting valve 3 is adjusted, part of the flue gas in the main flue 2 is introduced into the baking chamber 6 through the bypass flue 4 to heat the heated objects, and the cooled flue gas is introduced back into the main flue 2 through the bypass flue 4; S3, the opening degrees of the smoke adjusting valve 3, the inlet valve 5 and the outlet valve 8 are adjusted, so that the flue gas temperature at the end of the main flue 2 is always higher than 650 DEG C-700 DEG C; the flue gas temperature in the baking chamber 6 is gradually increased and maintained in the range of 80 DEG C-600 DEG C; S4, when the flue gas temperature of the main flue 2 is lower than 650 DEG C-700 DEG C, the inlet valve 5 and the outlet valve 8 of the baking chamber 6 are closed in turn, the smoke adjusting valve 3 is completely opened, and the cooling of the flue gas is stopped; S5, when the heating time of the heated objects reaches the requirement, the inlet valve 5 and the outlet valve 8 of the baking chamber 6 are closed in turn, then the smoke adjusting valve 3 is completely opened, and finally the heated objects are taken out. Further, the flow area of the bypass flue 4 is 30%-100% of that of the main flue 2. Further, in the single baking chamber 6 mode, the length of the baking chamber 6 is calculated according to the flue gas flow speed and flue gas flow time, so that the flue gas flowing through the baking chamber 6 is ensured to be not more than 2s, the flue gas flow speed of the baking chamber 6 is 2.86 m / s, and therefore the length of the baking chamber 6 is set to 5.7 m. Further, a hanging bag is arranged in the baking chamber 6, the hanging bag is used for placing the heated objects, and the hanging bag comprises two structural forms, i.e., a general hanging bag 12 and a customized hanging bag 7. The general hanging bag 12 is similar to a drawer, the bottom plate and the four side plates are 10 mm thick steel plates, the inner side of the steel plate is built with refractory material, the bottom surface is provided with 230 mm thick LZ-65 high-aluminum heat preservation bricks, and the four side surfaces are 230 mm thick light high-aluminum heat preservation bricks. The two sides of the general hanging bag 12 are provided with lifting rings. The heated objects placed in the general hanging bag 12 can be heated integrally or are not limited, such as molds and mother molds used in the production of recycled copper. The customized hanging bag 7 is different from the general hanging bag 12 in that a bag seat is additionally arranged.The ladle seat is cast on the ladle bottom of the general ladle 12 by pouring the castable, and is used for placing the tundish and pouring ladle for producing the secondary copper. After the tundish and pouring ladle are embedded into the ladle seat from top to bottom, only the castable layer on the upper surface of the tundish and pouring ladle is exposed in the air, and the tundish and pouring ladle are suitable for the heated objects which can only be heated on the partial surface. Further, the top of each roasting chamber 6 is provided with a cover plate 13, the top of the cover plate 13 is provided with a lifting ring, and the bottom surface of the cover plate 13 is provided with a heat preservation layer. After the application of the embodiment, the outlet flue gas temperature of the spray cooling tower 11 is 200℃, which meets the flue gas temperature requirement of ozone denitration; the inlet flue gas temperature of the spray cooling tower 11 is 680℃, which ensures the prevention and control effect on dioxin in the flue gas. At the same time, the water consumption of the spray cooling tower 11 is reduced by 30%. During the intermittent furnace, the roasting of the tundish and pouring ladle, or the roasting of the mother die and the die can be completed, and the natural gas consumption is saved by 216Nm3 / d. Embodiment 2 is described in detail below. Figure 2 , Figure 5The waste heat recovery system used in the embodiment is basically the same as that in Embodiment One, except that two baking chambers 6 are arranged in series on the bypass flue 4, and each baking chamber 6 is provided with a valve at the inlet and outlet thereof, and each baking chamber 6 is provided with a temperature sensor B9. The length of each baking chamber 6 is 5.7 m, the flue gas flow rate is 2.86 m / s, and the total time of flue gas flowing through the two baking chambers 6 is less than 5 seconds. After the application of the embodiment, the flue gas temperature at the outlet of the spray cooling tower 11 is reduced to 170℃, meeting the flue gas temperature requirement for ozone denitration; at the same time, the flue gas temperature at the inlet of the spray cooling tower 11 is 680℃, ensuring the prevention and control effect on dioxins in the flue gas. At the same time, the water consumption of the spray cooling tower 11 is reduced by 36%. During the intermittent production of the continuous refining furnace 1, the baking of the tundish, pouring ladle and part of the mold can be completed at the same time, saving 380 Nm3 / d of natural gas.When the intermediate ladle or pouring ladle is the heated object, the temperature of the baking chamber 6 is controlled in the 1st to 4th stages. When the mold or the master mold is the heated object, the temperature of the baking chamber 6 is controlled in the 1st to 5th stages. 6. When the flue gas temperature of the continuous refining furnace 1 is lower than 680℃, the inlet valve 5 and the outlet valve 8 of each baking chamber 6 are closed in sequence, the smoke adjusting valve 3 is fully opened, and the cooling of the flue gas is stopped. 7. When the heating time of the heated object reaches the requirement, the inlet valve 5 and the outlet valve 8 of the baking chamber 6 where the heated object is located are closed in sequence, the cover plate 13 of the baking chamber 6 is lifted out, the lifting ladle is lifted out, and finally the heated object is taken out. The above steps are repeated to bake the heated object. The heated object, the lifting ladle and the cover plate 13 are all lifted by the travelling crane. After the application of the embodiment, the flue gas temperature at the outlet of the spray cooling tower 11 is reduced to 140℃, which meets the smoke temperature requirement of ozone denitration; at the same time, the flue gas temperature at the inlet of the spray cooling tower 11 is 670℃, which ensures the prevention and control effect of dioxin in the flue gas. At the same time, the water consumption of the spray cooling tower 11 is reduced by 45%. During the intermittent furnace period, the baking of the heated object for full set of pouring production can be completed, and the natural gas consumption is saved by 520 Nm3 / d.

Claims

1. A method for recovering waste heat from a continuous refining furnace, characterized by: A waste heat recovery system is used for waste heat recovery. The waste heat recovery system includes at least one bypass flue. The inlet and outlet of all bypass flues are connected to the main flue of the continuous refining furnace. A baking chamber is provided in the middle of each bypass flue. The baking chamber is used to place objects to be heated. The smoke inlet and smoke outlet of each baking chamber are provided with valves. The main flue is provided with a smoke regulating valve. A temperature sensor A is provided at the starting end and the end of the main flue, and a temperature sensor B is provided in each baking chamber. The waste heat recovery method includes the following steps: S1. When the continuous refining furnace is in production, close the inlet valve and outlet valve of the baking chamber in sequence, and then place the object to be heated into the corresponding baking chamber; S2. When the flue gas temperature of the continuous refining furnace is higher than 700°C, open the inlet and outlet valves of the baking chamber, adjust the opening of the smoke regulating valve, and introduce part of the flue gas in the main flue into the baking chamber through the bypass flue to heat the material to be heated. The cooled flue gas is then introduced back into the main flue through the bypass flue. S3. Adjust the opening of the smoke regulating valve, inlet valve, and outlet valve to ensure that the smoke temperature at the end of the main flue is always higher than 650℃~700℃; control the smoke temperature in the baking chamber to gradually increase and maintain it in the range of 80℃~600℃; S4. When the flue gas temperature in the main flue is lower than 650℃~700℃, close the inlet valve and outlet valve of the baking chamber in sequence, fully open the smoke regulating valve, and stop cooling the flue gas; S5. When the heating time of the object to be heated reaches the requirement, first close the inlet valve and outlet valve of the baking chamber in sequence, then fully open the smoke adjustment valve, and finally take out the object to be heated.

2. The method for recovering waste heat from a continuous refining furnace according to claim 1, wherein: When the number of bypass flues exceeds one, the bypass flues are connected in parallel and are all connected to the main flue.

3. The method for recovering waste heat from a continuous refining furnace according to claim 2, wherein: The flow area of ​​each bypass flue is 30% to 100% of the main flue.

4. The method for recovering waste heat from a continuous refining furnace according to claim 1, wherein: Each bypass flue is provided with at least one baking chamber, and the baking chambers are arranged in series or in parallel.

5. The method for recovering waste heat from a continuous refining furnace according to claim 4, wherein: The length of each baking chamber is calculated according to the flue gas flow rate and flue gas flow time. When there is only one baking chamber on a bypass flue, ensure that the time for the flue gas to flow through the baking chamber is less than 3 seconds. When multiple baking chambers are set on a bypass flue, ensure that the total time for the flue gas to flow through all baking chambers is less than 5 seconds.

6. The method for recovering waste heat from a continuous refining furnace according to claim 4, wherein: When the baking chambers are arranged in parallel, the different baking chamber temperatures are divided into 2 to 6 temperature sections, and the continuous baking time of each temperature section is 0.2 to 4 hours.

7. The method for recovering waste heat from a continuous refining furnace according to claim 1, wherein: A hanging bag is provided in the baking chamber for placing objects to be heated. The hanging bag has two structural forms: a general hanging bag and a customized hanging bag. The general hanging bag is suitable for objects to be heated that are heated as a whole, and the customized hanging bag is used for objects to be heated that are heated on part of the surface.

8. The method for recovering waste heat from a continuous refining furnace according to claim 1, wherein: A cover plate is provided on the top of each baking chamber, a lifting ring is provided on the top of the cover plate, and an insulation layer is provided on the bottom surface of the cover plate.

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