Radiation and convection combined heat exchanger and waste heat recovery method

Abstract

The application discloses a radiation and convection combined heat exchanger and a waste heat recovery method, and belongs to the technical field of non-ferrous metal smelting energy saving and consumption reduction. The radiation and convection combined heat exchanger comprises a total flue gas inlet, a total flue gas outlet, a primary heat exchanger and a secondary heat exchanger, the primary heat exchanger is a radiation heat exchanger, the secondary heat exchanger is a convection heat exchanger, the primary heat exchanger is connected with the total flue gas inlet, the secondary heat exchanger is connected with the total flue gas outlet, and the flue gas outlet of the primary heat exchanger is located above the flue gas inlet of the secondary heat exchanger. The radiation and convection combined heat exchanger is used for recycling and utilizing the waste heat of flue gas in sequence through the primary heat exchanger and the secondary heat exchanger, and the heat of the flue gas in the copper refining anode furnace smelting process is used for preheating the gas for the anode furnace smelting, so that the energy consumption of the anode furnace smelting can be greatly reduced, and the green and efficient development of enterprises is promoted.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of energy saving and consumption reduction of non-ferrous metal smelting, more specifically, relates to a radiation and convection combined heat exchanger and a waste heat recovery method. BACKGROUND

[0002] The copper refining anode furnace is a copper refining equipment widely used in modern times, and is widely used in large copper smelting plants at home and abroad. It has the advantages of large capacity, high degree of mechanization and automation, flexible operation, small heat loss, good sealing performance and the like. However, the anode furnace is also the main energy consumption in the whole copper smelting production process. With the increasing shortage of energy supply, stricter requirements for environmental protection are put forward. Therefore, at the present stage, it is urgent to develop new energy-saving and consumption-reducing technologies and equipment.

[0003] The copper refining anode furnace smelting process is divided into four smelting stages: holding, oxidation, reduction and casting. The flue gas in the oxidation stage is as high as about 1300℃, and the flue gas generated in the reduction stage can reach as high as about 1400℃. For this part of the flue gas heat, many enterprises will directly discharge it through the exhaust pipe after diluting with cold air, without recovering and utilizing the waste heat.

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

[0005] Patent CN103449390A discloses a thermal method phosphoric acid waste heat utilization device with a radiation and convection heat exchange surface, which comprises a steam pocket, a downcomer, a steam guide pipe and a special phosphorus combustion tower. The special phosphorus combustion tower is composed of an upper head, a convection evaporation section, a transition section, a radiation heat exchange evaporation section, a phosphorus injection gun, a secondary air suction pipe, a lower head and a skirt. Phosphorus and combustion air are injected into the special phosphorus combustion tower through the phosphorus injection gun, mixed and combusted, and the high-temperature gas generated is first subjected to radiation heat exchange with the radiation evaporation section, and then enters the convection evaporation section to continue heat exchange with the convection heat exchange evaporation surface to reduce the temperature to below 400℃, and is then guided to the water tower by the gas outlet pipe.

[0006] However, the above patents are not suitable for the recovery and utilization of the flue gas of the copper refining anode furnace with high dust content. SUMMARY

[0007] 1. Problem to be solved

[0008] In view of the problem of recovering and utilizing the high-temperature flue gas waste heat of the existing anode furnace, the first object of the present application is to provide a radiation and convection combined heat exchanger which can realize the recovery and utilization of flue gas waste heat.

[0009] Another object of the present application 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 gas for anode furnace smelting.

[0010] 2. Technical solution

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

[0012] A radiation and convection combined heat exchanger, comprising a total flue gas inlet, a total flue gas outlet, a primary heat exchanger and a secondary heat exchanger. The primary heat exchanger is connected to the total flue gas inlet, and the secondary heat exchanger is connected to the total flue gas outlet. A dilution chamber is provided between the total flue gas inlet and the total flue gas outlet.

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

[0014] The shell of the primary heat exchanger is made of 347H stainless steel with a thickness of 3-10 mm. The inner diameter of the inner ring of the shell is 1000-3000 mm, and the outer diameter of the outer ring is 1000-4000 mm. The outer diameter of the outer ring is designed to be no more than the inner diameter of the dilution chamber of the anode furnace. The inner diameters of the first cold medium fluid inlet and the first cold medium fluid outlet are equal, and are 70-300 mm. The first guide plate is made of 347H stainless steel and is placed in the cavity between the inner ring and the outer ring of the primary heat exchanger, with a thickness of 3-10 mm.

[0015] The primary heat exchanger is welded in the flue gas pipeline, and two intersecting square steels are provided in the flue gas pipeline. The square steels are fixed through the wall surface of the dilution chamber, and the primary heat exchanger is welded on the square steels.

[0016] The secondary heat exchanger comprises a second flue gas inlet, a second flue gas outlet, a second cold medium fluid inlet and a second cold medium fluid outlet, the first flue gas outlet is located above the second flue gas inlet, the second flue gas outlet is connected to the total flue gas outlet, wherein a plurality of second guide plates are arranged in the secondary heat exchanger, the second guide plates are arranged in parallel with each other, so that a bent flue is formed in the secondary heat exchanger. The second cold medium fluid inlet and the second cold medium fluid outlet are arranged on the shell of the secondary heat exchanger, wherein the second flue gas inlet is located above the second flue gas outlet, and the second cold medium fluid inlet is located below the second cold medium fluid outlet.

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

[0018] The secondary heat exchanger is fixed on the flue gas pipeline, and an angle steel is arranged at the bottom of the secondary heat exchanger, and the secondary heat exchanger is fixed by the angle steel and screws.

[0019] The flue is provided with a flow dividing device, the flow dividing 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 flow dividing device comprises 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 protruding from the flap is arranged on the central axis of the flap, the rotating shaft protrudes from the flue gas pipeline, and a rotating handle is arranged at the end of the rotating shaft, wherein the flap is made of 347H stainless steel with a thickness of 30-50 mm, and is two identical semicircular shapes, the diameter of the semicircle is 1000-4000 mm; the rotating shaft is made of 347H stainless steel, and has a length of 2000-5000 mm and a diameter of 70-90 mm; and the rotating handle is made of 347H stainless steel.

[0020] A dilution air port is further arranged below the flow dividing device, and is used for introducing dilution gas, the distance between the dilution air port and the first flue gas outlet of the primary heat exchanger is 2050-3000 mm.

[0021] The radiation and convection combined heat exchanger of the present application is a self-recycling technology for realizing the cascade utilization of high-temperature flue gas waste heat resources of an anode furnace and recycling the waste heat resources. The high-temperature flue gas of the anode furnace is subjected to the first utilization of flue gas waste heat through the internal primary heat exchanger of the dilution chamber. After the flue gas is subjected to the primary waste heat utilization through the primary heat exchanger, the flue gas can be divided into two routes: if the secondary utilization of flue gas waste heat is not required, the flue gas can be directly discharged into the flue gas total outlet; if the secondary utilization of waste heat is required, according to the smelting requirements of the anode furnace, when the preheating of the alternating intermittent consumption gas for the smelting of the anode furnace is required, the flapper can be used for flow guiding to guide the flue gas of the anode furnace into the secondary heat exchanger for the secondary utilization of flue gas waste heat.

[0022] The present application also discloses a method for recycling 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 of the anode furnace is subjected to the first utilization of flue gas waste heat through the primary heat exchanger;

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

[0025] If the secondary utilization of waste heat is required, the flapper is used for flow guiding to guide the flue gas of the anode furnace into the secondary heat exchanger for the 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 total outlet.

[0027] 3. Beneficial effects

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

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

[0030] (2) The radiation and convection combined heat exchanger of the present application further utilizes the gas in the dilution chamber to increase the turbulence degree of the flue gas by adjusting the running direction of the flue gas, so that the flue gas collides with the pipeline to deposit the dust particles, thereby reducing the particles in the discharged flue gas and reducing the discharge of smoke;

[0031] (3) The waste heat recycling method of the present application uses the heat of the flue gas in the smelting process of the copper refining anode furnace to preheat the gas for the smelting of the anode furnace, which can greatly reduce the energy consumption of the smelting of the anode furnace and promote the green and efficient development of enterprises. BRIEF DESCRIPTION OF DRAWINGS

[0032] The technical solutions of the present application will be described in further detail below in combination with the drawings and examples, but it should be understood that these drawings are designed only for the purpose of explanation, and therefore do not limit the scope of the present application. In addition, unless specifically indicated, these drawings are only intended to conceptually illustrate the structural configurations described herein, and are not necessarily drawn to scale.

[0033] Figure 1 Structure diagram of the radiation and convection combined heat exchanger of the present application;

[0034] Figure 2 Structure diagram of the primary heat exchanger of the present application;

[0035] Figure 3 Structure diagram of the secondary heat exchanger of the present application;

[0036] Figure 4 Structure diagram of the flow dividing device of the present application;

[0037] Figure 5 Temperature cloud diagram of the numerical simulation of the primary heat exchanger;

[0038] Figure 6 Velocity cloud diagram of the numerical simulation of the primary heat exchanger;

[0039] Figure 7 Temperature cloud diagram of the numerical simulation of the secondary heat exchanger;

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

[0041] In the drawings: 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 cold medium fluid inlet; 36, first cold medium fluid outlet; 37, first flue gas inlet; 38, first flue gas outlet;

[0044] 4, dilution chamber; 41, dilution air inlet;

[0045] 5, secondary heat exchanger; 51, second cold medium fluid inlet; 52, second cold medium fluid outlet; 53, second flue gas inlet; 54, second flue gas outlet; 55, second guide plate;

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

[0047] The following detailed description of exemplary embodiments of the invention is taken with reference to the accompanying drawings, which form part of the description and illustrate exemplary embodiments in which the invention may be practiced. While these exemplary embodiments have been described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be implemented and various changes may be made to the invention without departing from the spirit and scope thereof. The more detailed description of embodiments of the invention below is not intended to limit the scope of the claimed invention, but is merely illustrative and not restrictive of the description of the features and characteristics of the invention, to suggest the best mode for carrying out the invention, and is sufficient to enable those skilled in the art to practice the invention. Therefore, the scope of the invention is defined only by the appended claims.

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

[0049] The following is in conjunction with the appendix Figures 1 to 6 The present invention provides a detailed description of the combined radiation and convection heat exchanger:

[0050] Example

[0051] A combined radiation and convection 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, and the secondary heat exchanger 5 is connected to the total flue gas outlet 2. 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 radiant heat exchanger, such as... Figures 2-3 As shown, it includes an outer ring 31 and an inner ring 32, with a cavity 33 formed between the outer ring 31 and the inner ring 32. A first guide plate 34 is provided in the cavity 33, and the first guide plate 34 spirals upward within the cavity 33. A first cold medium fluid outlet 36 and a first cold medium fluid inlet 35 are provided on the outer ring 31. The first cold medium fluid outlet 36 is located above the first cold medium fluid inlet 35. The upper end of the first stage heat exchanger 3 is the first flue gas inlet 37, and the lower end of the first stage heat exchanger 3 is the first flue gas outlet 38. The direction of the first flue gas inlet 37 is perpendicular to the direction of the total flue gas inlet.

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

[0054] The primary heat exchanger 3 is welded into the flue gas duct. Specifically, the flue gas duct is provided with two intersecting square steel bars. The square steel bars pass through the wall of the dilution chamber 4 and are fixed thereon. The primary heat exchanger 3 is welded onto the square steel bars. The square steel bars are made of high alloy steel and have a side length of 40-80mm. In Example 1, square steel bars with a side length of 40mm are used.

[0055] The secondary heat exchanger 5 is a convection heat exchanger, such as... Figure 4 As shown, it includes a second flue gas inlet 53, a second flue gas outlet 54, a second cold medium fluid inlet 51, and a second cold medium fluid outlet 52. The second flue gas inlet 53 is connected to the dilution chamber 4, and the second flue gas outlet 54 is connected to the total flue gas outlet 2. The secondary heat exchanger 5 is provided with several second guide plates 55, which are arranged parallel to each other, forming a bent flue in the secondary heat exchanger 5. The shell of the secondary heat exchanger 5 has a second cold medium fluid inlet 51 and a second cold medium fluid outlet 52, wherein the second flue gas inlet 53 is located above the second flue gas outlet 54, and the second cold medium fluid inlet 51 is located below the second cold medium fluid outlet 52. Specifically, in embodiment 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 enters the secondary flue gas outlet 54 from the second flue gas outlet 54 under the guidance of the second guide plates 55 and bends twice. In actual process, three or more second guide plates 55 can be selected according to the final temperature required for the flue gas to be discharged, so as to extend the heat exchange path of the flue gas in the secondary heat exchanger 5.

[0056] The shell of the secondary heat exchanger 5 in Example 1 is made of 310S stainless steel with a thickness of 3 mm, an inner diameter of 33 mm, and an outer diameter of 38 mm. The second flue gas inlet 54 adopts a structure of a round place, specifically, a circular inlet is adopted at the inlet of the second flue gas inlet 54, and a flared portion is connected at the rear end of the circular inlet, and the cross section of the flared portion is square. It is surprisingly found that the inlet structure with this structure causes the flue gas to diffuse to the edge of the flue at the flared portion, so that the flue gas is distributed at each height of the upper, middle and lower flues. The existing straight-through flue causes the flue gas to be distributed only at the middle and below of the flue due to the action of gravity, and cannot contact the top of the flue. The application adds the flow guiding effect of the flared portion, so that the flue gas is distributed at each height of the flue, the contact area with the heat exchange tube is increased, and the heat exchange efficiency is improved. In addition, due to the increase in the degree of turbulence of the flue gas in the flue, the particles in the flue gas collide with the flue tube wall, so that more dust particles fall on the second flow 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 for the anode furnace reaction stage, reducing the introduction of impurities in the reaction process.

[0057] The second cold medium fluid inlet 51 adopts a circular truncated cone-shaped inlet with an inner diameter of 150 mm, the second flow guide plate 55 is made of 310S stainless steel with a thickness of 3 mm, and the second cold 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 pipeline, and the secondary heat exchanger 5 is provided with an angle steel at the bottom, and the secondary heat exchanger 5 is fixed by the angle steel and screws. The angle steel is made of structural steel, and the width of the angle steel is 20-50 mm and the thickness of the angle steel is 3-6 mm. In Example 1, an angle steel with a width of 20 mm and a thickness of 3 mm is adopted.

[0059] It is worth noting that since the flue gas used in the present application for waste heat recovery is the flue gas carried out of the copper refining anode furnace, it contains a large amount of particulate soot, in order to avoid the deposition of this part of impurities on the surface of the heat exchanger, affecting the heat exchange performance, and even causing blockage in the heat exchanger pipe, therefore the first flue gas outlet 38 of the first heat exchanger 3 is arranged above the second flue gas inlet 53 of the second 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 collides with the pipe below the dilution chamber 4 first, and deposits most of the soot, further, the degree of turbulence of the flue gas is increased by the gas in the dilution chamber 4, the flue gas containing soot particles collides and deposits in the dilution chamber 4, so that the particulate soot in the flue gas entering the second heat exchanger 5 from the second flue gas inlet 53 is greatly reduced; after the flue gas passes through the second heat exchanger 5, the remaining soot particles are deposited by the second baffle 55 provided in the second heat exchanger 5 and the bending section of the second baffle 55, thereby reducing the particles in the discharged flue gas and reducing the discharge of smoke.

[0060] In order to realize free switching of flue gas recovery, a flow splitting device 6 is arranged in the flue, which is located below the dilution chamber 4, the flow splitting device 6 includes a flap 61, a rotating shaft 62 extending out of the flap 61 is arranged on the axis of the flap 61, the rotating shaft 62 extends out of the flue gas pipe, and a rotating handle 63 is arranged at the end of the rotating shaft 62. In embodiment 1, the flap 61 is two identical semicircles, which are made of 347H stainless steel with a thickness of 30mm, and the diameter of the semicircle is 2050mm; the rotating shaft 62 is made of 347H stainless steel, which is a bar 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 also includes a dilution air inlet 41 for introducing dilution gas, which is located below the flap 61, and the distance between the dilution air inlet 41 and the first flue gas outlet 38 of the first heat exchanger 3 is 2050mm.

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

[0063] In view of the smelting characteristics of the anode furnace, the gas consumed by the anode furnace is partly used for combustion of the burner, and the other part of the gas is used for smelting of the furnace body. In order to ensure the temperature atmosphere in the furnace, the burner will always be burning, and for the smelting of the furnace body, the smelting is divided into four stages of holding, oxidation, reduction and casting, and the types and amounts of gas used in each stage are different. Among them, 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 is preheated, the temperature atmosphere in the furnace can be effectively improved, the use of fuel can be reduced, and the energy saving and consumption reduction of the anode furnace can be realized, so that the production cost of the enterprise is effectively reduced.

[0064] The present application recovers the waste heat of the anode furnace flue gas, which is used to preheat the combustion-supporting compressed air used by the anode furnace burner for combustion, and the nitrogen, compressed air and the like used for smelting in the furnace. In view of the fact that the combustion-supporting compressed air used by the burner is a continuous consumption gas, and the nitrogen and compressed air used for smelting in the furnace is an alternating intermittent consumption gas, the first heat exchanger 3 is used to preheat the combustion-supporting air used by the burner; and for the nitrogen and compressed air required for smelting in the furnace, the second heat exchanger 5 can be used, when the furnace body is smelted, the flap 61 is rotated to make the flue gas enter the second heat exchanger 5, and the nitrogen or compressed air is introduced through the second cold medium fluid inlet 51, at this time, the smelting gas can be preheated. The waste heat recovery and utilization of the flue gas needs to realize cascade utilization and alternating heat exchange of nitrogen and compressed air, so as to meet the overall preheating of the gas under various production conditions.

[0065] The radiation and convection combined heat exchanger of the present application realizes cascade utilization of the high-temperature flue gas waste heat resource of the anode furnace and self-reuse technology of waste heat resource reuse. The high-temperature flue gas of the anode furnace is subjected to first utilization of flue gas waste heat in the first heat exchanger 3 inside the dilution chamber 4, and the flue gas after the first waste heat utilization in the first heat exchanger 3 can be divided into two paths: if there is no need for secondary utilization of flue gas waste heat, it can be directly discharged into the flue gas total outlet 2; if secondary utilization of waste heat is needed, according to the smelting requirements of the anode furnace, when the alternating intermittent consumption gas for smelting of the anode furnace needs to be preheated, the flap 61 can be used for flow guiding to guide the anode furnace flue gas into the second heat exchanger 5 for secondary utilization of flue gas waste heat.

[0066] Wherein, in order to realize the primary heat exchanger 3 as the primary utilization of the anode furnace high-temperature flue gas waste heat resource, according to the above design of the primary heat exchanger 3 in the dilution chamber 4, numerical simulation is carried out for the heat exchanger. According to the anode furnace smelting characteristics, the anode furnace smelting flue gas characteristics in the heat preservation stage are selected, the anode furnace flue gas temperature is set to 1400 DEG C, the flue gas speed is 0.8 m / s, according to the anode furnace burner combustion condition, the primary heat exchanger 3 preheats the compressed air for anode furnace combustion, the compressed air inlet temperature is 26 DEG C, the inlet speed is 12 m / s, by means of ANSYS Fluent numerical simulation simulation platform, the numerical simulation of the heat exchange effect of the primary heat exchanger 3, i.e. the radiation heat exchanger, is carried out, and the anode furnace high-temperature flue gas temperature and speed, the compressed air inlet temperature and speed are used as the boundary conditions of the numerical simulation of the primary heat exchanger 3. Finally, the temperature nephogram and the speed nephogram of the primary heat exchanger 3 are as shown in Figure 5 、 Figure 6 It can be seen that after the anode furnace high-temperature flue gas passes through the primary heat exchanger 3, the temperature is reduced to about 738 DEG C, and the compressed air outlet temperature of the primary heat exchanger 3 is 325 DEG C. According to the numerical simulation result, it can be seen that under the premise of ensuring the safety of industrial production, the radiation heat exchanger has strong practicability.

[0067] Figure 6 The speed nephogram for the numerical simulation of the primary heat exchanger 3 is shown in the figure. It can be seen from the figure that the fluid mainly flows along the annular channel, and there is obvious streamline bending phenomenon in the bending area and the pipeline connection. The speed size shows significant difference in different areas, and the high-temperature area is often accompanied by higher flow speed, which shows that the temperature gradient has a significant influence on the flow field. In addition, there may be speed vortex or separation phenomenon in some local areas, which is closely related to the complex geometric structure and boundary conditions in the heat exchanger. At the outlet of the primary heat exchanger 3, the flow speed is large, which also corresponds to the temperature of the cold medium fluid after being preheated, which is much higher than the inlet temperature. Since the primary heat exchanger 3 first contacts the 1400 DEG C anode furnace flue gas, higher requirements are put forward for its high-temperature resistance. Through the regulation of speed and temperature, the influence of local temperature on the heat exchanger is reduced, which shows the rationality and efficiency of the design of the primary heat exchanger 3.

[0068] The secondary heat exchanger 5, also known as the bypass convection heat exchanger 5, is used for the secondary utilization of waste heat resources from the high-temperature flue gas of the anode furnace. Based on the design of the secondary heat exchanger 5, a numerical simulation was performed 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 from the high-temperature flue gas of the anode furnace decreases to 738℃ after primary utilization. Therefore, in the numerical simulation of the secondary heat exchanger 5, the flue gas inlet temperature was set to 738℃ and the flue gas inlet velocity was set to 4m / s. Based on the gas requirements for anode furnace smelting, it is assumed that the preheating gas is compressed air. Therefore, the compressed air inlet temperature of the secondary heat exchanger 5 was set to 26℃ and the inlet velocity to 18m / s. Using the ANSYS Fluent numerical simulation platform, the heat exchange effect of the secondary heat exchanger 5 was numerically simulated. The resulting temperature and velocity cloud maps of the secondary heat exchanger 5 are shown below. Figure 7 and Figure 8 As shown in the figure, the temperature of the compressed air after preheating can reach 335℃, while the flue gas outlet temperature is 578℃, allowing it to be directly discharged into the exhaust pipe. According to the numerical simulation results, it can be seen that, under the premise of ensuring industrial production safety, this secondary heat exchanger 5 can effectively utilize waste heat for anode furnace smelting, 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 exhaust pipe. Therefore, this application calculates / designs to reduce the flue gas outlet temperature to 738°C after the 1400°C flue gas is heated by the primary heat exchanger 3 of this application. If the secondary heat exchanger 5 outside the dilution room is not needed, it can be directly mixed 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 before being discharged.

[0070] The above description is merely a preferred embodiment of this application and an explanation of the technical principles used. Those skilled in the art should understand that the scope involved in this application is not limited to the technical solutions 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. For example, technical solutions formed by replacing the above-mentioned features with technical features with similar functions disclosed in this application (but not limited to) each other.

[0071] Apart from the technical features described in the specification, the other technical features are known to those skilled in the art. To highlight the innovative features of this invention, the other technical features will not be described in detail here.

Claims

1. A combined radiation and convection heat exchanger, characterized in that, 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), and the secondary heat exchanger (5) is connected to the total flue gas outlet (2). The first flue gas outlet (38) at the lower end of the primary heat exchanger (3) is located above the second flue gas inlet (53) of the secondary heat exchanger (5). The upper end of the primary heat exchanger (3) is the first flue gas inlet (37), and the lower end of the primary heat exchanger (3) is the first flue gas outlet (38). The direction of the first flue gas inlet (37) is perpendicular to the direction of the total flue gas inlet (1). The primary heat exchanger (3) includes an outer ring (31) and an inner ring (32), and 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), and the first guide plate (34) spirals upward in the cavity (33). A first cold medium fluid inlet (35) and a first cold medium fluid outlet (36) are provided on the outer ring (31), and the first cold medium fluid outlet (36) is located above the first cold medium fluid inlet (35). The secondary heat exchanger (5) includes a second flue gas inlet (53), a second flue gas outlet (54), a second cold medium inlet (51), and a second cold medium outlet (52). The second flue gas inlet (53) is connected to the dilution chamber (4), and the second flue gas outlet (54) is connected to the total flue gas outlet (2). The secondary heat exchanger (5) is provided with a plurality of second guide plates (55), which are arranged in parallel to each other, so that a bent flue is formed in the secondary heat exchanger (5). The direction of the first flue gas outlet (38) is perpendicular to the direction of the second flue gas inlet (53); The shell of the secondary heat exchanger (5) has a second cold medium fluid inlet (51) and a second cold medium fluid outlet (52), wherein the second flue gas inlet (53) is located above the second flue gas outlet (54), and the second cold medium fluid inlet (51) is located below the second cold medium fluid outlet (52). The flue is provided with a diversion device (6), which is located below the primary heat exchanger (3) and the secondary heat exchanger (5). The diversion 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). The rotating shaft (62) extends out of the flue gas pipe, and a rotating handle (63) is provided at the end of the rotating shaft (62).

2. The combined radiation and convection heat exchanger according to claim 1, characterized in that, The diversion device (6) is provided with a dilution air inlet (41) below it for introducing dilution gas.

3. The combined radiation and convection heat exchanger according to claim 2, characterized in that, The distance between the dilution air outlet (41) and the first flue gas outlet (38) of the first stage heat exchanger (3) is 2050-3000 mm.

4. A method for waste heat recovery using the combined radiation and convection heat exchanger as described in any one of claims 1-3, characterized in that, The specific steps include: Step S1: The high-temperature flue gas from the anode furnace is recycled and utilized through a primary heat exchanger (3). Step S2: After the flue gas has undergone primary waste heat utilization through the primary heat exchanger (3), if there is no need for secondary flue gas waste heat recovery, it can be directly discharged into the total flue gas outlet (2). If secondary flue gas waste heat recovery and utilization is required, the anode furnace flue gas is introduced into the secondary heat exchanger (5) for secondary utilization of flue gas waste heat; Step S3: The flue gas after passing through the secondary heat exchanger (5) is discharged through the main flue gas outlet (2).

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