Radiation and convection combined heat exchanger and waste heat recovery method

Abstract

The invention discloses a radiation and convection combined heat exchanger and a waste heat recovery method, and belongs to the technical field of energy conservation and consumption reduction in non-ferrous metal smelting. The radiation and convection combined heat exchanger comprises a flue gas main inlet, a flue gas main outlet, a first-stage heat exchanger and a second-stage heat exchanger, the first-stage heat exchanger is a radiation heat exchanger, the second-stage heat exchanger is a convection heat exchanger, the first-stage heat exchanger is connected with the flue gas main inlet, the second-stage heat exchanger is connected with the flue gas main outlet, and the first-stage heat exchanger is connected with the convection heat exchanger. And a flue gas outlet of the first-stage heat exchanger is positioned above a flue gas inlet of the second-stage heat exchanger. According to the radiation and convection combined heat exchanger, flue gas waste heat is recycled through the first-stage heat exchanger and the second-stage heat exchanger in sequence, heat of flue gas in the smelting process of a copper refining anode furnace is used for preheating gas for smelting of the anode furnace, the smelting energy consumption of the anode furnace can be reduced to a great extent, and green and efficient development of enterprises is promoted.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy saving and consumption reduction in nonferrous metal smelting, and more specifically, relates to a radiation and convection combined heat exchanger and a waste heat recovery method. Background Art

[0002] Copper refining anode furnace is a copper refining equipment commonly used in modern times. It is widely used in large copper smelters at home and abroad. It has the advantages of large capacity, high degree of mechanization and automation, flexible operation, small heat dissipation loss, good sealing, etc. However, the anode furnace is also the largest energy consumer in the entire copper smelting production process. As energy supply becomes increasingly tight, more stringent requirements are also put forward for environmental protection. Therefore, it is urgent to develop new energy-saving and consumption-reducing technologies and equipment at this stage.

[0003] The copper refining anode furnace smelting process is divided into four smelting stages: insulation, oxidation, reduction and casting. The flue gas temperature in the oxidation stage is as high as about 1300°C, and the flue gas temperature in the reduction stage is as high as about 1400°C. In view of the heat of this part of the flue gas, many companies will directly discharge it through the exhaust pipe after adding diluted cold air, without recovering the waste heat.

[0004] After searching, patent CN111435026A discloses a radiation convection heat exchanger and an air conditioner having the same. Specifically, the radiation convection heat exchanger includes: a radiation heat exchange part, which is in the shape of a cylinder with two ends open, configured to absorb heat or cold from its inner wall surface, and radiate heat or cold from its outer wall surface to the outside; a first convection heat exchange part, which is arranged on the inner side of the radiation heat exchange part, configured to generate heat or cold, and transfer heat or cold to the air flowing through the inner side of the radiation heat exchange part, and transfer heat or cold to the inner wall surface of the radiation heat exchange part; and a second convection heat exchange part, which is configured to generate heat or cold, and perform heat exchange with the air flowing through it; the radiation heat exchange part is arranged on the upper side or lower side of the second convection heat exchange part.

[0005] Patent CN103449390A discloses a thermal phosphoric acid waste heat utilization device with a radiation convection heat exchange surface, which includes a steam drum, a downcomer, a steam guide pipe and a special phosphorus burning tower, which is composed of an upper head, a convection evaporation section, a transition section, a radiation heat exchange evaporation section, a phosphorus spray gun, a secondary air suction pipe, a lower head and a skirt. After phosphorus and combustion-supporting air are sprayed into the special phosphorus burning tower through the phosphorus spray gun and mixed and burned, the high-temperature gas generated first undergoes radiation heat exchange with the radiation evaporation section, and the temperature drops below 800°C before entering the convection evaporation section to continue heat exchange and cooling with the convection heat exchange evaporation surface, and the temperature drops below 400°C and is guided to the hydration tower by the gas outlet pipe.

[0006] However, the above patents are not applicable to the recovery and utilization of flue gas from anode furnaces for copper refining with high dust content. Summary of the invention

[0007] 1. Problem to be solved

[0008] In view of the problem of recycling waste heat from high-temperature flue gas in existing anode furnaces, the first purpose of the present invention is to provide a radiation and convection combined heat exchanger, which can realize the recycling of waste heat from flue gas.

[0009] Another object of the present invention is to provide a waste heat recovery method, which uses the heat of flue gas in the copper refining anode furnace smelting process to preheat the anode furnace smelting gas.

[0010] 2. Technical solution

[0011] In order to solve the above problems, the technical solution adopted by the present invention is as follows:

[0012] A radiation and convection combined heat exchanger comprises a total smoke inlet, a total smoke outlet, a primary heat exchanger and a secondary heat exchanger, wherein the primary heat exchanger is connected to the total smoke inlet, the secondary heat exchanger is connected to the total smoke outlet, and a dilution chamber is provided in the flue between the total smoke inlet and the total smoke outlet.

[0013] The primary heat exchanger comprises an outer ring and an inner ring, a cavity is formed between the outer ring and the inner ring, a first guide plate is arranged in the cavity, and the first guide plate rises in a spiral in the cavity. A first cooling medium fluid outlet and a first cooling medium fluid outlet inlet are provided on the outer ring, the first cooling medium fluid outlet is located above the first cooling medium fluid outlet inlet, the upper end of the primary heat exchanger is a first smoke inlet, the lower end of the primary heat exchanger is a first smoke outlet, and the direction of the first smoke inlet is perpendicular to the direction of the total smoke inlet.

[0014] The shell of the first-stage heat exchanger is made of 347H stainless steel with a thickness of 3-10mm. The inner diameter of the shell is 1000-3000mm and the outer diameter is 1000-4000m. The outer diameter is designed not to exceed the inner diameter of the anode furnace dilution chamber. The inner diameters of the first cold medium fluid inlet and the first cold medium fluid outlet are equal, 70-300mm. The first guide plate is made of 347H stainless steel and is placed in the cavity of the inner and outer rings of the first-stage heat exchanger with a thickness of 3-10mm.

[0015] The primary heat exchanger is welded in the flue gas duct, and two crossed square steels are arranged in the flue gas duct. The square steels pass through the wall of the dilution chamber for fixation, and the primary heat exchanger is welded on the square steels.

[0016] The secondary heat exchanger includes a second smoke inlet, a second smoke outlet, a second cooling medium fluid inlet and a second cooling medium fluid outlet, wherein the first smoke outlet is located above the second smoke inlet, and the second smoke outlet is connected to the main smoke outlet, wherein a plurality of second guide plates are provided in the secondary heat exchanger, and the second guide plates are arranged in parallel with each other, so that a curved flue is formed in the secondary heat exchanger. The shell of the secondary heat exchanger is provided with a second cooling medium fluid inlet and a second cooling medium fluid outlet, wherein the second smoke inlet is located above the second smoke outlet, and the second cooling medium fluid inlet is located below the second cooling medium fluid outlet.

[0017] The secondary heat exchanger shell is made of 310S stainless steel, with an inner diameter of 32-52mm, an outer diameter of 37-58mm, and a thickness of 3-10mm; the second cold medium fluid inlet adopts a truncated cone inlet, the inner diameter of the bottom of the cone is 150-300mm, and a second guide plate is arranged in the secondary heat exchanger, the second guide plate is made of 310S stainless steel, the thickness of the second guide plate is 2-4mm, and the second cold medium fluid outlet is a square outlet, the side length of which is 100-200mm.

[0018] The secondary heat exchanger is fixed on the flue gas duct. An angle steel is provided at the bottom of the secondary heat exchanger, and the angle steel and screws are used to fix the secondary heat exchanger.

[0019] A diverter device is provided in the flue, and the diverter device is located below the primary heat exchanger and the secondary heat exchanger, and is used for guiding the flue gas into the secondary heat exchanger. The diverter device includes a flap. Preferably, the flap is parallel to the lower end of the second flue gas inlet of the secondary heat exchanger. A rotating shaft extending out of the flap is provided on the central axis of the flap, and the rotating shaft extends out of the flue gas duct. A rotating handle is provided at the end of the rotating shaft, wherein the flap is made of 347H stainless steel with a thickness of 30-50mm, and is two identical semicircles with a semicircle diameter of 1000-4000mm; the rotating shaft is made of 347H stainless steel, and its specifications are rods with a length of 2000-5000mm and a diameter of 70-90mm, and the rotating handle is made of 347H stainless steel.

[0020] It also includes a dilution air port, which is arranged below the diversion device and is used to introduce dilution gas. The distance between the dilution air port and the first flue gas outlet of the first-stage heat exchanger is 2050-3000mm.

[0021] The radiation and convection combined heat exchanger of the present application is a technology for realizing the cascade utilization of the waste heat resources of the high-temperature flue gas of the anode furnace and the recycling and self-recycling of the waste heat resources. The high-temperature flue gas of the anode furnace passes through the first-level heat exchanger inside the dilution chamber for the first utilization of the waste heat of the flue gas. After passing through the first-level heat exchanger for the first-level waste heat utilization, the flue gas may be divided into two paths: if there is no need for the second-level utilization of the flue gas waste heat, it can be directly discharged into the main flue gas outlet; if the second-level utilization of the waste heat is required, then according to the smelting requirements of the anode furnace, when it is necessary to preheat the anode furnace smelting alternating intermittent consumption gas, a flap can be used for diversion, and the anode furnace flue gas can be introduced into the second-level heat exchanger for the second-level utilization of the flue gas waste heat.

[0022] The present invention also discloses a method for recovering waste heat by using the above-mentioned radiation and convection combined heat exchanger, which specifically comprises the following steps:

[0023] Step S1, the high-temperature flue gas from the anode furnace passes through a primary heat exchanger to utilize the flue gas waste heat for the first time;

[0024] Step S2, after the flue gas has been subjected to primary waste heat utilization in the primary heat exchanger, if secondary waste heat utilization of the flue gas is not required, it is directly discharged into the main flue gas outlet;

[0025] If secondary utilization of waste heat is required, a flap is used to guide the anode furnace flue gas into the secondary heat exchanger for secondary utilization of flue gas waste heat;

[0026] Step S3: the flue gas after passing through the secondary heat exchanger is directly discharged through the flue gas main outlet.

[0027] 3. Beneficial effects

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The radiation and convection combined heat exchanger of the present invention recycles the waste heat of flue gas through the primary heat exchanger and the secondary heat exchanger in sequence, and uses the heat of flue gas in the copper refining anode furnace smelting process to preheat the anode furnace smelting gas, which can greatly reduce the energy consumption of anode furnace smelting and promote the green and efficient development of enterprises;

[0030] (2) The radiation and convection combined heat exchanger of the present invention adjusts the direction of the flue gas and further utilizes the gas in the dilution chamber to increase the turbulence of the flue gas, so that the flue gas collides with the pipe and deposits smoke particles, thereby reducing the particles in the discharged flue gas and reducing the discharge of smoke;

[0031] (3) The waste heat recovery method of the present invention can greatly reduce the energy consumption of anode furnace smelting by using the heat of flue gas in the copper refining anode furnace smelting process to preheat the anode furnace smelting gas, thereby promoting the green and efficient development of the enterprise. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments, but it should be understood that these drawings are designed only for explanation purposes and are not intended to limit the scope of the present invention. In addition, unless otherwise specified, these drawings are intended only to conceptually illustrate the structural configurations described herein and are not necessarily drawn to scale.

[0033] Figure 1 This is a schematic diagram of the structure of the radiation and convection combined heat exchanger of this application;

[0034] Figure 2 This is a schematic diagram of the structure of the primary heat exchanger for this application;

[0035] Figure 3 This is a schematic diagram of the structure of the secondary heat exchanger for this application;

[0036] Figure 4 This is a schematic diagram of the diversion device structure of this application;

[0037] Figure 5 This is the temperature cloud diagram of the numerical simulation of the first-stage heat exchanger;

[0038] Figure 6 This is the velocity cloud diagram of the numerical simulation of the first-stage heat exchanger;

[0039] Figure 7 This is the temperature cloud diagram of the numerical simulation of the secondary heat exchanger;

[0040] Figure 8 Velocity cloud diagram for numerical simulation of the secondary heat exchanger;

[0041] In the figure: 1. Total flue gas inlet;

[0042] 2. Total flue gas outlet;

[0043] 3. primary heat exchanger; 31. outer ring; 32. inner ring; 33. cavity; 34. first guide plate; 35. first cooling medium fluid inlet; 36. first cooling medium fluid outlet; 37. first flue gas inlet; 38. first flue gas outlet;

[0044] 4. Dilution chamber; 41. Dilution air outlet;

[0045] 5. Secondary heat exchanger; 51. Second cooling medium fluid inlet; 52. Second cooling medium fluid outlet; 53. Second flue gas inlet; 54. Second flue gas outlet; 55. Second guide plate;

[0046] 6. diversion device; 61. flap; 62. rotating shaft; 63. rotating handle. DETAILED DESCRIPTION

[0047] The following detailed description of exemplary embodiments of the present invention refers to the accompanying drawings, which form a part of the description, and in which exemplary embodiments of the present invention that can be implemented are shown as examples. Although these exemplary embodiments are described in sufficient detail to enable those skilled in the art to implement the present invention, it should be understood that other embodiments can be implemented and various changes can be made to the present invention without departing from the spirit and scope of the present invention. The following more detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but is only for the purpose of illustrating and not limiting the description of the characteristics and features of the present invention, so as to propose the best mode for performing the present invention and to enable those skilled in the art to implement the present invention. Therefore, the scope of the present invention is limited only by the appended claims.

[0048] It should be understood that the following text is only used to describe one or several specific embodiments of the present invention, and does not strictly limit the scope of protection of the specific claims of the present invention. As used herein, the terms "parallel" and "perpendicular" are not limited to their strict geometric definitions, but include tolerances for reasonable and inconsistent machining or human errors.

[0049] The following is combined with Figures 1 to 6 , the radiation and convection combined heat exchanger of the present invention is described in detail:

[0050] Example

[0051] A radiation and convection combined heat exchanger, such as Figure 1 As shown, it includes a total flue gas inlet 1, a total flue gas outlet 2, a primary heat exchanger 3 and a secondary heat exchanger 5. The primary heat exchanger 3 is connected to the total flue gas inlet 1, the secondary heat exchanger 5 is connected to the total flue gas outlet 2, and a dilution chamber 4 is provided between the primary heat exchanger 3 and the secondary heat exchanger 5.

[0052] The primary heat exchanger 3 is a radiation heat exchanger, such as Figure 2-3 As shown, it comprises an outer ring 31 and an inner ring 32, a cavity 33 is formed between the outer ring 31 and the inner ring 32, a first guide plate 34 is arranged in the cavity 33, and the first guide plate 34 rises in a spiral in the cavity 33. A first cooling medium fluid outlet 36 and a first cooling medium fluid inlet 35 are provided on the outer ring 31, the first cooling medium fluid outlet 36 is located above the first cooling medium fluid inlet 35, the upper end of the primary heat exchanger 3 is a first smoke inlet 37, the lower end of the primary heat exchanger 3 is a first smoke outlet 38, and the direction of the first smoke inlet 37 is perpendicular to the direction of the total smoke inlet.

[0053] The shell of the primary heat exchanger 3 in Example 1 is made of 347H stainless steel with a thickness of 3mm, the diameter of the inner ring 32 of the shell is 1934mm, the diameter of the outer ring 31 is 2040m, and the diameter of the outer ring 31 is designed not to exceed the inner diameter 2100mm of the anode furnace dilution chamber 4. The inner diameters of the first cooling medium fluid inlet 35 and the first cooling medium fluid outlet 36 are equal, which is 70mm, and the first guide plate 34 is made of 347H stainless steel with a thickness of 3mm.

[0054] The primary heat exchanger 3 is welded in the flue gas duct. Specifically, two crossed square steels are provided in the flue gas duct. The square steels pass through the wall of the dilution chamber 4 for fixation. The primary heat exchanger 3 is welded on the square steels. The square steels are made of high alloy steel. The side length of the square steels is 40-80 mm. In Example 1, square steels with a side length of 40 mm are used.

[0055] The secondary heat exchanger 5 is a countercurrent heat exchanger, such as Figure 4 As shown, it includes a second smoke inlet 53, a second smoke outlet 54, a second cooling medium fluid inlet 51 and a second cooling medium fluid outlet 52, wherein the second smoke inlet 53 is connected to the dilution chamber 4, and the second smoke outlet 54 is connected to the smoke total outlet 2, wherein the secondary heat exchanger 5 is provided with a plurality of second guide plates 55, and the second guide plates 55 are arranged in parallel with each other, so that a curved flue is formed in the secondary heat exchanger 5. The shell of the secondary heat exchanger 5 is provided with a second cooling medium fluid inlet 51 and a second cooling medium fluid outlet 52, wherein the second smoke inlet 53 is located above the second smoke outlet 54, and the second cooling medium fluid inlet 51 is located below the second cooling medium fluid outlet 52. Specifically, in Example 1, two second guide plates 55 are provided, so that a flue with two bends is formed in the secondary heat exchanger 5. The flue gas passes through the second flue gas inlet 53 and, under the guiding action of the second guide plate 55, passes through two bends and enters the total flue gas outlet 2 from the second flue gas outlet 54. In actual process, three second guide plates 55 or more second guide plates 55 can also be selected according to the final flue gas discharge temperature to extend the heat exchange path of the flue gas in the secondary heat exchanger 5.

[0056] In Example 1, the shell of the secondary heat exchanger 5 is made of 310S stainless steel with a thickness of 3mm, an inner diameter of 33mm, and an outer diameter of 38mm; wherein the second flue gas inlet 54 adopts a round and square structure, specifically, the inlet of the second flue gas inlet 54 adopts a circular inlet, the rear end of the circular inlet is connected to a flared port, and the cross section of the flared port is square. Surprisingly, it is found that with the inlet structure of this structure, the flue gas diffuses to the edge of the flue at the flared port, so that the flue gas is distributed at various heights of the upper, middle and lower parts of the flue. Due to the effect of gravity, the existing straight-through flue gas is only distributed in the middle and below the flue gas, and cannot contact the top of the flue gas. However, the present application adds the diversion effect of the flared port, so that the flue gas is distributed at various heights of the flue gas, increases the contact area with the heat exchange tube, and thus improves the heat exchange efficiency. In addition, as the turbulence of the flue gas in the flue increases, the particles in the flue gas collide with the flue wall, causing more smoke particles to fall onto the second guide plate 55 below, effectively improving the cleanliness of the flue gas, so that the flue gas discharged through the secondary heat exchanger 5 can be directly used in the anode furnace reaction stage, reducing the introduction of impurities in the reaction process.

[0057] The second cooling medium fluid inlet 51 is a truncated cone-shaped inlet with an inner diameter of 150 mm, the second guide plate 55 is made of 310S stainless steel with a thickness of 3 mm, and the second cooling medium fluid outlet 52 is a square outlet with a side length of 100 mm.

[0058] The secondary heat exchanger 5 is fixed on the flue gas duct, and an angle steel is provided at the bottom of the secondary heat exchanger 5, and the angle steel and screws are used to fix the secondary heat exchanger 5. The angle steel is made of structural steel, and the angle steel side width is 20-50mm, and the angle steel side thickness is 3-6mm. In Example 1, an angle steel with a side width of 20mm and a side thickness of 3mm is used.

[0059] It is worth noting that since the flue gas used for waste heat recovery in this application is the flue gas brought out from the copper refining anode furnace, it contains a large amount of particulate smoke. In order to avoid this part of impurities being deposited on the surface of the heat exchanger, affecting the heat exchange performance, and even causing blockage in the heat exchanger pipeline, the first flue gas outlet 38 of the first-stage heat exchanger 3 is arranged above the second flue gas inlet 53 of the second-stage heat exchanger 5, and the direction of the first flue gas outlet 38 is perpendicular to the direction of the second flue gas inlet 53, so that the flue gas passing through the first flue gas outlet 38 is firstly connected to the flue gas outlet 53 below the dilution chamber 4. The flue gas collides with the pipe and most of the smoke is deposited. Furthermore, the gas in the dilution chamber 4 is used to increase the turbulence of the smoke. The smoke containing smoke particles collides and deposits in the dilution chamber 4, so that the granular smoke in the smoke entering the secondary heat exchanger 5 from the second smoke inlet 53 is greatly reduced. After the smoke passes through the secondary heat exchanger 5, the remaining smoke particles are deposited through the second guide plate 55 and the bending section of the second guide plate 55 provided in the secondary heat exchanger 5, thereby reducing the particles in the discharged smoke and reducing the discharge of smoke.

[0060] In order to realize the free switching of flue gas recovery, a diverter device 6 is provided in the flue, and the diverter device 6 is located below the dilution chamber 4. The diverter device 6 includes a flap 61, and a rotating shaft 62 extending out of the flap 61 is provided on the central axis of the flap 61, and the rotating shaft 62 extends out of the flue gas duct, and a rotating handle 63 is provided at the end of the rotating shaft 62. In Example 1, the flap 61 is two identical semicircles, which are made of 347H stainless steel with a thickness of 30mm and a semicircle diameter of 2050mm; the rotating shaft 62 is made of 347H stainless steel, and its specification is a rod with a length of 2330mm and a diameter of 70mm, and the rotating handle 63 is made of 347H stainless steel.

[0061] The dilution chamber 4 further includes a dilution air port 41 for introducing dilution gas. The dilution air port 41 is located below the flap 61 . The distance between the dilution air port 41 and the first flue gas outlet 38 of the primary heat exchanger 3 is 2050 mm.

[0062] Using the heat of flue gas during the copper refining anode furnace smelting process to preheat the anode furnace smelting gas can greatly reduce the anode furnace smelting energy consumption and promote the green and efficient development of the enterprise.

[0063] In view of the smelting characteristics of the anode furnace, part of the gas consumed is used for burner combustion, and the other part of the gas is used for furnace smelting. In order to ensure the temperature atmosphere in the furnace, the burner will continue to burn. According to the smelting of the furnace body, the smelting is divided into four stages: insulation, oxidation, reduction and casting. The type and amount of gas used in each stage are different. Compressed air is introduced in the oxidation stage, and nitrogen and natural gas are introduced in the reduction stage. If the combustion and smelting gas of the anode furnace are preheated, the temperature atmosphere in the furnace can be effectively increased, the use of fuel can be reduced, and the energy saving and consumption reduction of the anode furnace can be achieved, so that the production cost of the enterprise can be effectively reduced.

[0064] The present application recycles the waste heat of the anode furnace flue gas, which is used to preheat the combustion-supporting compressed air used for the combustion of the anode furnace burner, as well as the nitrogen and compressed air used for smelting in the furnace. In view of the fact that the combustion-supporting compressed air used by the burner is a continuously consumed gas, and the nitrogen and compressed air used for smelting in the furnace are alternating intermittently consumed gases, the primary heat exchanger 3 preheats the combustion-supporting air used by the burner; and for the nitrogen and compressed air required for smelting in the furnace, the secondary heat exchanger 5 can be used. When the furnace body is smelting, the flap 61 is rotated to allow the flue gas to enter the secondary heat exchanger 5, and nitrogen or compressed air is introduced through the second cold medium fluid inlet 51, and the smelting gas can be preheated at this time. In order to recover and utilize the waste heat of the flue gas, it is necessary to realize cascade utilization and alternate heat exchange of nitrogen and compressed air, so as to meet the comprehensive preheating of the gas under various production conditions.

[0065] The radiation and convection combined heat exchanger of the present application is a technology for realizing the cascade utilization of the waste heat resources of the high-temperature flue gas of the anode furnace and the recycling and self-recycling of the waste heat resources. The high-temperature flue gas of the anode furnace passes through the primary heat exchanger 3 inside the dilution chamber 4 for the first utilization of the waste heat of the flue gas. After the flue gas passes through the primary heat exchanger 3 for the primary waste heat utilization, it can be divided into two paths: if there is no need for secondary utilization of the waste heat of the flue gas, it can directly enter the main flue gas outlet 2 for discharge; if secondary utilization of waste heat is required, then according to the smelting requirements of the anode furnace, when it is necessary to preheat the anode furnace smelting alternating intermittent consumption gas, the flap 61 can be used for diversion, and the anode furnace flue gas can be introduced into the secondary heat exchanger 5 for secondary utilization of the waste heat of the flue gas.

[0066] Among them, in order to realize the primary utilization of the waste heat resources of the high-temperature flue gas of the anode furnace by the primary heat exchanger 3, a numerical simulation is performed on this heat exchanger according to the design of the primary heat exchanger 3 inside the dilution chamber 4 mentioned above. According to the smelting characteristics of the anode furnace, the present invention selects the characteristics of the anode furnace smelting flue gas in the insulation stage, sets the anode furnace flue gas temperature to 1400°C, and the flue gas velocity to 0.8m / s. According to the combustion conditions of the anode furnace burner, the primary heat exchanger 3 preheats the compressed air for combustion of the anode furnace, and the compressed air inlet temperature is 26°C and the inlet velocity is 12m / s. With the help of the ANSYS Fluent numerical simulation platform, a numerical simulation is performed on the heat exchange effect of the primary heat exchanger 3, i.e., the radiation heat exchanger, and the temperature and velocity of the anode furnace high-temperature flue gas, and the compressed air inlet temperature and velocity are used as the boundary conditions for the numerical simulation of the primary heat exchanger 3. Finally, the temperature cloud map and velocity cloud map of the primary heat exchanger 3 are as follows: Figure 5 , Figure 6 As shown. It can be seen that after the high-temperature flue gas of the anode furnace passes through the primary heat exchanger 3, the temperature is reduced to about 738°C, and the outlet temperature of the compressed air of the primary heat exchanger 3 is 325°C. According to the numerical simulation results, it can be seen that the radiation heat exchanger has strong practicality under the premise of ensuring the safety of industrial production.

[0067] Figure 6 It is the velocity cloud map of the numerical simulation of the first-stage heat exchanger 3. It can be seen from the figure that the fluid mainly flows along the annular channel, and there is an obvious streamline bending phenomenon in the bending area and the pipe connection. The velocity magnitude shows significant differences in different areas, and the high-temperature area is often accompanied by a higher flow rate, which indicates that the temperature gradient has a significant impact on the flow field. In addition, there may be velocity vortices or separation phenomena in some local areas, which is closely related to the complex geometric structure and boundary conditions inside the heat exchanger. At the outlet of the first-stage heat exchanger 3, its flow rate is relatively large, which also corresponds to the fact that after the cold medium fluid is preheated, its temperature is much higher than the inlet temperature. Since the first-stage heat exchanger 3 first contacts the 1400°C anode furnace flue gas, it puts forward higher requirements for its high temperature tolerance. This application reduces the impact of excessive local temperature on the heat exchanger by regulating the speed and temperature, indicating the rationality and efficiency of the design of the first-stage heat exchanger 3.

[0068] The secondary heat exchanger 5, i.e., the bypass convection heat exchanger 5, is the secondary utilization of the waste heat resources of the high-temperature flue gas of the anode furnace. According to the above design of the secondary heat exchanger 5, a numerical simulation is performed on this heat exchanger as an implementation case. According to the numerical simulation of the primary heat exchanger 3 inside the dilution chamber 4, the temperature of the waste heat resources of the high-temperature flue gas of the anode furnace is reduced to 738°C after the primary utilization. Therefore, in the numerical simulation of the secondary heat exchanger 5, the flue gas inlet temperature is set to 738°C and the flue gas inlet velocity is set to 4m / s. According to the gas required for smelting in the anode furnace, it is now assumed that the preheating gas is compressed air. Therefore, the compressed air inlet temperature of the secondary heat exchanger 5 is set to 26°C and the inlet velocity is 18m / s. Similarly, with the help of the ANSYS Fluent numerical simulation platform, the heat exchange effect of the secondary heat exchanger 5 is numerically simulated. The temperature cloud map and velocity cloud map of the secondary heat exchanger 5 are respectively as shown below: Figure 7 and Figure 8 As shown. It can be seen that after preheating, the temperature of the compressed air can reach 335°C, and the flue gas outlet temperature is 578°C, which can be directly discharged into the exhaust pipe. According to the numerical simulation results, it can be seen that under the premise of ensuring the safety of industrial production, the secondary heat exchanger 5 can effectively waste heat anode furnace smelting gas, greatly reducing the energy consumption required for anode furnace smelting.

[0069] According to the safety requirements of industrial production, the high-temperature flue gas from the anode furnace needs to be reduced to below 500°C before it can be discharged through the smoke exhaust duct. Therefore, the present application calculates / designs that the 1400°C flue gas is heat exchanged by the primary heat exchanger 3 of the present application, so that the flue gas outlet temperature is reduced to 738°C. If the secondary heat exchanger 5 outside the dilution chamber is not needed, it can be directly added with dilution cold air for discharge. If the secondary heat exchanger 5 is working, the flue gas can be directly passed into the secondary heat exchanger 5 for secondary utilization of the flue gas waste heat, and then discharged.

[0070] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope involved in the present application is not limited to the technical solution formed by a specific combination of the above-mentioned technical features, but should also cover other technical solutions formed by any combination of the above-mentioned technical features or their equivalent features without departing from the inventive concept, such as a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features with similar functions disclosed in this application.

[0071] Except for the technical features described in the specification, the remaining technical features are known technologies to those skilled in the art. In order to highlight the innovative features of the present invention, the remaining technical features will not be described here in detail.

Claims

1. A radiation and convection combined heat exchanger, characterized in that: The invention comprises a total smoke inlet (1), a total smoke outlet (2), a primary heat exchanger (3) and a secondary heat exchanger (5), wherein the primary heat exchanger (3) is connected to the total smoke inlet (1), the secondary heat exchanger (5) is connected to the total smoke outlet (2), and a first smoke outlet (38) at the lower end of the primary heat exchanger (3) is located above a second smoke inlet (53) of the secondary heat exchanger (5).

2. The radiation and convection combined heat exchanger according to claim 1 is characterized in that: The upper end of the primary heat exchanger (3) is a first smoke inlet (37), and the lower end of the primary heat exchanger (3) is a first smoke outlet (38). The direction of the first smoke inlet (37) is perpendicular to the direction of the total smoke inlet (1).

3. The radiation and convection combined heat exchanger according to claim 2 is characterized in that: The primary heat exchanger (3) comprises an outer ring (31) and an inner ring (32), a cavity (33) is formed between the outer ring (31) and the inner ring (32), a first guide plate (34) is provided in the cavity (33), the first guide plate (34) rises in a spiral in the cavity (33), a first cooling medium fluid inlet (35) and a first cooling medium fluid outlet (36) are provided on the outer ring (31), and the first cooling medium fluid outlet (36) is located above the first cooling medium fluid inlet (35).

4. The radiation and convection combined heat exchanger according to claim 3 is characterized in that: The secondary heat exchanger (5) comprises a second smoke inlet (53), a second smoke outlet (54), a second cooling medium fluid inlet (51) and a second cooling medium fluid outlet (52); the second smoke inlet (53) is connected to the dilution chamber (4); the second smoke outlet (54) is connected to the main smoke outlet (2); a plurality of second guide plates (55) are provided in the secondary heat exchanger (5); the second guide plates (55) are arranged parallel to each other, so that a bent smoke duct is formed in the secondary heat exchanger (5).

5. The radiation and convection combined heat exchanger according to claim 4 is characterized in that: The direction of the first smoke outlet (38) is perpendicular to the direction of the second smoke inlet (53).

6. The radiation and convection combined heat exchanger according to claim 5, characterized in that: A second cooling medium fluid inlet (51) and a second cooling medium fluid outlet (52) are provided on the shell of the secondary heat exchanger (5), wherein the second smoke gas inlet (53) is located above the second smoke gas outlet (54), and the second cooling medium fluid inlet (51) is located below the second cooling medium fluid outlet (52).

7. The radiation and convection combined heat exchanger according to claim 6, characterized in that: A flow diverter (6) is provided in the flue, and the flow diverter (6) is located below the primary heat exchanger (3) and the secondary heat exchanger (5). The flow diverter (6) comprises a flap (61), and a rotating shaft (62) extending out of the flap (61) is provided on the central axis of the flap (61), and the rotating shaft (62) extends out of the flue gas duct, and a rotating handle (63) is provided at the end of the rotating shaft (62).

8. The radiation and convection combined heat exchanger according to claim 7, characterized in that: A dilution air port (41) is provided below the diversion device (6) for introducing dilution gas.

9. The radiation and convection combined heat exchanger according to claim 8, characterized in that: The distance between the dilution air port (41) and the first flue gas outlet (38) of the primary heat exchanger (3) is 2050-3000 mm.

10. A method for waste heat recovery using the radiation and convection combined heat exchanger according to any one of claims 1 to 9, characterized in that: The specific steps include: Step S1, the high-temperature flue gas from the anode furnace passes through the primary heat exchanger (3) to recover the primary flue gas waste heat; Step S2, after the flue gas has been subjected to primary waste heat utilization in the primary heat exchanger (3), if secondary waste heat recovery of the flue gas is not required, it directly enters the flue gas main outlet (2) for discharge; If secondary flue gas waste heat recovery is required, the anode furnace flue gas is introduced into the secondary heat exchanger (5) for secondary utilization of the flue gas waste heat; Step S3: The flue gas after passing through the secondary heat exchanger (5) is discharged through the flue gas main outlet (2).

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