A roasting furnace waste heat recovery device

Abstract

The application relates to a roasting furnace waste heat recovery device and belongs to the technical field of industrial waste heat recovery. The device comprises a storage tank, a cover connected to the top of the storage tank, an air inlet and an air outlet fixedly connected to the side wall of the storage tank and the center of the cover respectively, a waste heat recovery assembly connected to the outer wall of the air outlet, a heat absorption box fixedly connected to the outer wall of the air outlet, phase change materials filled in the heat absorption box, and a plurality of heat spreading plates fixedly connected to the outer wall of the heat absorption box, a waste heat processing box arranged at one side of the storage tank and connected to the heat absorption box through a connecting assembly, and a heat absorption assembly device arranged in the waste heat processing box and comprising a plurality of mother liquid fins and a serpentine bent pipe connected to the mother liquid fins. The application realizes waste heat gradient recovery through three-stage processes of dust removal, heat storage and heat exchange. The gas conveying pipeline has the heat exchange function, and the design of the in-tank turbulence and counterflow significantly improves the heat exchange efficiency.

Description

Technical Field

[0001] This application relates to the technical field of industrial waste heat recovery, and in particular to a waste heat recovery device for a roasting furnace. Background Technology

[0002] Currently, in the roasting processes of industries such as non-ferrous metal smelting and chemicals, the flue gas discharged from the roasting furnace typically has a high temperature (up to several hundred degrees Celsius), containing a large amount of usable waste heat. At the same time, this high-temperature flue gas often contains dust. Directly discharging this high-temperature flue gas not only results in a huge waste of energy but may also affect the normal operation of subsequent environmental protection equipment due to its excessively high temperature. To recover this energy, cooling and dust removal treatment of the flue gas is usually necessary.

[0003] In related technologies, waste heat boilers or air preheaters are often used to directly exchange heat with flue gas to recover heat. While this method recovers some heat, it suffers from problems such as large system size, high investment costs, and strict requirements on flue gas quality. Especially when dealing with high-dust, high-temperature roasting furnace flue gas, high-temperature dust easily scales and wears down the heat exchange surfaces, reducing heat exchange efficiency and service life. Furthermore, existing technologies for waste heat recovery are relatively simple, focusing mainly on generating steam or heating air, making it difficult to flexibly and efficiently apply the heat to stages of the process that require specific temperature heat sources, and the waste heat quality is not utilized in a tiered manner.

[0004] Regarding the aforementioned technologies, the inventors believe that the following defects exist: existing waste heat recovery devices do not adequately pre-treat the flue gas when handling high-dust, high-temperature roasting furnace flue gas, which can easily lead to damage to heat exchange equipment and efficiency reduction; at the same time, the utilization of waste heat from the flue gas is limited, the energy recovery rate needs to be improved, and it is difficult to achieve cascaded utilization and targeted supply of energy. Summary of the Invention

[0005] In order to improve the problems of insufficient pretreatment, low heat recovery efficiency and single utilization form in the existing waste heat recovery of calcining furnace flue gas, this application provides a waste heat recovery device for calcining furnace.

[0006] The waste heat recovery device for a roasting furnace provided in this application adopts the following technical solution: A waste heat recovery device for a roasting furnace includes a storage tank and a cover connected to the top of the storage tank, and further includes an air inlet and an air outlet, which are respectively fixedly connected to the side wall of the storage tank and the center of the cover. Waste heat recovery assembly, which is connected to the outer wall of the air outlet, includes a heat absorption box fixedly connected to the outer wall of the air outlet, a phase change material filled in the heat absorption box, and several heat spreaders fixedly connected to the outer wall of the heat absorption box. Waste heat processing boxes are spaced apart on one side of the storage tank and connected to the heat absorption box via connecting components; The heat absorption assembly device installed in the waste heat processing box includes several mother liquor fins and serpentine bends connected to the mother liquor fins.

[0007] By adopting the above technical solution, this device constructs an integrated, multi-stage waste heat recovery system. The storage tank first performs preliminary cyclone dust removal on the high-temperature, dust-laden flue gas, protecting subsequent heat exchange equipment. When the purified flue gas is discharged through the outlet, its heat is absorbed by the waste heat recovery components through both phase change heat storage and convection radiation, achieving primary cooling and thermal energy storage. Subsequently, the cooled flue gas is introduced into the waste heat processing box through connecting components, where it undergoes deep heat exchange with the heat absorption components, efficiently and directionally transferring heat to the process fluid. The entire process achieves tiered energy utilization of "dust removal - primary phase change heat storage recovery - secondary fluid heating recovery," improving overall heat recovery efficiency and adapting to process requirements.

[0008] Preferably, several of the heat spreaders are located below the air intake, and the heat spreaders are tilted toward the side facing the direction of gravity.

[0009] By adopting the above technical solution and placing the heat spreader below the air inlet, the rising heat flow of the high-temperature flue gas entering the storage tank from the air inlet can be effectively utilized to enhance convective heat transfer. The heat spreader's inclination towards gravity helps guide the heated air to rise naturally, creating a chimney effect that continuously carries away heat, enhancing the heat dissipation efficiency of the heat spreader to the surrounding environment, while also preventing rainwater from accumulating on the plate.

[0010] Preferably, the lower part of the inner wall of the storage tank is in the shape of a conical funnel, a dust discharge pipe is fixedly connected to the bottom of the storage tank, and a dust storage tank is fixedly connected to the end of the dust discharge pipe on the side away from the storage tank.

[0011] By adopting the above technical solution, the lower inner wall of the conical funnel shape helps guide the dust particles separated by centrifugal force to gather towards the bottom center, preventing dust from accumulating in corners. The gathered dust is finally discharged into the dust storage tank through the dust discharge pipe, realizing continuous dust collection and cleaning, ensuring unobstructed flow inside the storage tank and the continuity of dust removal effect, and providing cleaner flue gas for subsequent heat exchange processes.

[0012] Preferably, the connecting assembly includes a first connecting air passage fixedly connected between the storage tank and the waste heat processing box, a second connecting air passage fixedly connected at the end of the first connecting air passage away from the waste heat processing box, and the end of the second connecting air passage away from the first connecting air passage extending into the heat absorption box.

[0013] By adopting the above technical solution, the connecting components form a channel for flue gas to flow from the primary recovery unit (storage tank and waste heat recovery components) to the secondary recovery unit (waste heat processing box). The second connecting gas duct extends into the heat absorption box, so that the flow path of the flue gas is wrapped by the phase change material inside the heat absorption box before entering the waste heat processing box. In this way, the flue gas can be further cooled by the phase change material during transportation, and the phase change material absorbs this heat, its temperature rises, and it may even undergo a phase change, thus achieving deep recovery of waste heat from the flue gas and cooling protection of the transportation pipeline.

[0014] Preferably, an electrically controlled valve is fixedly connected to the first connecting air passage, and at least two first process interfaces are provided. The first process interfaces are spaced apart on the side of the electrically controlled valve near the storage tank, and a sensor is fixedly connected to each first process interface.

[0015] By adopting the above technical solution, the electrically controlled valve can be used to control the on / off state and flow regulation of flue gas pipelines. The first process interface located upstream of the electrically controlled valve (near the storage tank side) can be used to connect equipment such as pressure gauges, thermometers, and sampling tubes. Sensors connected to each interface can monitor key parameters such as the pressure and temperature of the flue gas at that point in real time, providing data support for the system's automated control and operational status monitoring, thereby improving the intelligence and operability of the device.

[0016] Preferably, the maximum height of the phase change material inside the heat absorption box is lower than that of the second connecting air duct, and a filter screen is fixedly connected to the inner wall of the second connecting air duct.

[0017] By adopting the above technical solution, the phase change material filling height is lower than the inlet of the second connecting gas channel, which can effectively prevent the liquid or solid phase change material from clogging the flue gas channel when it expands or flows due to heat. The filter screen can intercept trace substances that may be carried in the flue gas, volatilized from the phase change material, or tiny dust particles that escape from the storage tank, preventing them from entering the electronic control valve, sensor, or subsequent pipelines, thus playing a dual role in protecting the equipment and ensuring the cleanliness of the flue gas.

[0018] Preferably, a baffle pipe is fixedly connected to the inner wall of the waste heat processing box, the baffle pipe is inclined and the air outlet of the baffle pipe points to the bottom wall of the waste heat processing box, and an exhaust pipe is fixedly connected to the top surface of the waste heat processing box.

[0019] By employing the above technical solution, the turbulence pipe forces a drastic change in the direction of the flue gas entering the waste heat processing box, transforming it from a horizontal or inclined inflow to a downward impact on the bottom of the box. This turbulence and impact disrupt the laminar flow of the flue gas, enhancing its turbulence and resulting in more thorough contact between the flue gas and the mother liquid fins and serpentine bends, leading to more uniform and efficient heat exchange. Finally, the cooled flue gas after heat exchange is discharged from the top exhaust pipe.

[0020] Preferably, the outlet end and inlet end of the serpentine bend are fixedly connected to the top and bottom walls of the waste heat processing box, respectively.

[0021] By adopting the above technical solution, this connection method allows the process fluid requiring heating (such as cold mother liquor) to enter the serpentine bend from the bottom inlet and flow upwards through the entire heat exchange area. During the flow, the fluid continuously absorbs heat transferred from the flue gas through the mother liquor fins, gradually increasing its temperature, and finally flows out from the top outlet. This method conforms to the principle of "counter-current heat exchange," where the cold fluid flows in the opposite direction to the gradually decreasing flue gas, maintaining a large heat transfer temperature difference, thereby achieving higher heat exchange efficiency and outlet fluid temperature.

[0022] Preferably, a second process interface is fixedly connected to the outer wall of the air intake, and a detection element is fixedly connected inside the second process interface.

[0023] By adopting the above technical solution and installing detection elements at the very front end of the flue gas entering the system, key parameters of the original high-temperature flue gas, such as temperature, can be monitored in real time. This data is crucial for evaluating the operating conditions of the roasting furnace, calculating the overall waste heat recovery efficiency, and controlling the subsequent waste heat recovery process.

[0024] Preferably, a plurality of first legs and second legs are fixedly connected to the outer walls of the storage tank and the waste heat processing box, respectively.

[0025] By adopting the above technical solution, the first and second outriggers provide stable and reliable support for the storage tank and waste heat processing box, allowing the entire device to be securely installed on the ground or foundation. The outriggers raise the bottom of the equipment, facilitating equipment inspection, maintenance, and pipeline connections, while also improving bottom ventilation and preventing localized corrosion.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. By combining the cyclone dust removal structure of the storage tank, the phase change thermal storage waste heat recovery component combined with the gas outlet, and the independent waste heat processing box, a three-stage treatment process of dust removal, primary thermal storage and cooling, and secondary directional heat exchange is realized for the high-temperature flue gas of the roasting furnace. This effectively solves the problem of damage to heat exchange equipment by high dust content and high temperature flue gas, and realizes the cascade, efficient recovery and diversified utilization of waste heat. 2. By extending the second connecting gas duct of the flue gas into the heat absorption box filled with phase change material, the flue gas is transported to the next heat exchange unit, and the transport pipe itself becomes a high-efficiency heat exchanger. This can further recover the heat of the flue gas and cool the pipe, thereby improving the heat recovery rate and system safety. 3. By installing a turbulence-inducing tube and a serpentine bend with mother liquor fins inside the waste heat processing box, the turbulent heat transfer effect between the flue gas and the heat exchange components is significantly enhanced. Furthermore, the counter-current heat transfer design maximizes the heating efficiency of the process fluid, achieving high-grade directional utilization of waste heat. Attached Figure Description

[0027] Figure 1 This is a perspective view illustrating the waste heat recovery device in the embodiments of this application.

[0028] Figure 2 yes Figure 1 Sectional view at TT.

[0029] Figure 3 yes Figure 2 A magnified view at point A.

[0030] Figure 4 This is a schematic diagram illustrating the structure of the waste heat recovery component in the embodiments of this application.

[0031] Figure 5 This is a structural schematic diagram illustrating the connecting component in the embodiments of this application.

[0032] Explanation of reference numerals in the attached drawings: 1. Storage tank; 12. First leg; 2. Cover; 3. Air inlet; 31. Second process interface; 32. Detection element; 4. Air outlet; 5. Waste heat recovery assembly; 51. Heat absorption box; 52. Phase change material; 53. Heat spreader; 6. Waste heat processing box; 61. Baffle pipe; 62. Exhaust pipe; 63. Second leg; 7. Connecting assembly; 71. First connecting air duct; 711. Electrically controlled valve; 712. First process interface; 7121. Sensor; 72. Second connecting air duct; 721. Filter screen; 8. Heat absorption assembly device; 81. Mother liquor fins; 82. Serpentine bend; 9. Dust exhaust pipe; 10. Dust storage tank. Detailed Implementation

[0033] The following is in conjunction with the appendix Figure 1-5 This application will be described in further detail.

[0034] This application discloses a waste heat recovery device for a roasting furnace, referring to... Figures 1 to 3 It includes a storage tank 1, a cover 2, an air inlet 3, an air outlet 4, a waste heat recovery component 5, a waste heat processing box 6, a connecting component 7, and a heat absorption component device 8.

[0035] Specifically, the air inlet 3 is fixedly connected to the upper part of the side wall of the storage tank 1, and a second process interface 31 is fixedly connected to the outer wall of the air inlet 3. A detection element 32 is fixedly connected inside the second process interface 31. In this embodiment, the detection element 32 is preferably a temperature sensor, and the probe of the temperature sensor extends into the air inlet 3. The cover 2 is fixedly connected to the top of the storage tank 1, and the air outlet 4 is fixedly connected to the center of the cover 2. The bottom of the air outlet 4 extends into the inner cavity of the storage tank 1. The lower part of the inner wall of the storage tank 1 is in the shape of a conical funnel. A dust discharge pipe 9 is fixedly connected to the center of the bottom of the storage tank 1. A dust collection tank 10 for collecting settled dust is fixedly connected to the end of the dust discharge pipe 9 away from the storage tank 1. Several first support legs 12 are fixedly connected around the lower part of the outer wall of the storage tank 1 to support the entire storage tank 1.

[0036] The principle behind this process is as follows: High-temperature, dust-laden flue gas enters the inner cavity of storage tank 1 tangentially along the side wall from inlet 3, forming a high-speed, downward-rotating external swirling airflow under the constraint of storage tank 1. Dust particles in the airflow are thrown towards the inner wall of storage tank 1 by centrifugal force. Under the combined action of gravity and the downward airflow, the captured dust slides down the lower inner wall, which is shaped like a conical funnel, and finally enters the dust storage tank 10 through the bottom dust discharge pipe 9 for collection. Simultaneously, the purified gas turns near the bottom of storage tank 1, forming an upward internal swirling flow, and is discharged from the central outlet 4, thus completing the initial dust removal and gas-solid separation of the flue gas.

[0037] Reference Figure 4 The waste heat recovery assembly 5 is installed inside the storage tank 1 and connected to the air outlet 4. The waste heat recovery assembly 5 includes a heat absorption box 51, a phase change material 52, and several heat spreaders 53. The heat absorption box 51 has an annular cross-sectional shape and is fixedly connected to the outer wall of the air outlet 4, forming a heat exchange contact with it. It should be noted that the heat absorption box 51 is made of copper. The phase change material 52 (preferably paraffin wax) fills the internal cavity of the heat absorption box 51. Several heat spreaders 53 are fixedly connected to the outer wall of the heat absorption box 51, and one side of the heat spreader 53 extends into the heat absorption box 51. The heat spreaders 53 are inclined towards the side facing the direction of gravity to increase the contact area with air and guide airflow.

[0038] The principle behind this is as follows: After initial dust removal in storage tank 1, the high-temperature flue gas is discharged upwards from the central outlet duct 4. During this process, the heat from the high-temperature flue gas is directly conducted through the pipe wall of outlet duct 4 to the heat absorption box 51 fixed to its outer wall. The phase change material 52 filled inside the heat absorption box 51 absorbs this heat energy, and its temperature rises to the phase change point, causing a phase change (from solid to liquid). During this phase change, it absorbs and stores a large amount of latent heat, thereby efficiently reducing the temperature of the flue gas flowing through outlet duct 4.

[0039] The waste heat processing box 6 is spaced apart on the side of the storage tank 1 away from the air inlet 3. The connecting assembly 7 is located between the waste heat processing box 6 and the storage tank 1, and is used to recover the high-temperature steam in the heat absorption box 51 for secondary processing and waste heat recovery. (Refer to...) Figure 5 The connecting component 7 includes a first connecting airway 71 and a second connecting airway 72.

[0040] One end of the first connecting air duct 71 is fixedly connected to the side of the waste heat processing box 6 near the storage tank 1, and the other end is fixedly connected to the second connecting air duct 72. An electric control valve 711 is fixedly connected to the outer wall of the first connecting air duct 71. The second connecting air duct 72 is fixedly connected to the heat absorption box 51 at the end away from the first connecting air duct 71, and is located at the upper part of the heat absorption box 51 near the waste heat processing box 6. It should be noted that in order to prevent the phase change material 52 from entering the second connecting air duct 72, the maximum filling height of the phase change material 52 in the heat absorption box 51 is lower than the opening at the end of the second connecting air duct 72. A filter screen 721 is fixedly connected to the inner wall of the second connecting air duct 72 to intercept a small amount of dust that may be carried with the flue gas and the phase change material 52 from entering the electric control valve 711.

[0041] In addition, a plurality of first process interfaces 712 (preferably two in this embodiment) are fixedly connected to the first connecting air passage 71. The first process interfaces 712 are spaced apart on the side of the electric control valve 711 near the storage tank 1 for connecting equipment. Each first process interface 712 is fixedly connected to a sensor 7121, which is a pressure sensor and a temperature sensor, respectively.

[0042] An exhaust pipe 62 is fixedly connected to the top surface of the waste heat processing box 6 for finally discharging the low-temperature flue gas that has undergone sufficient heat exchange. A turbulence-inducing pipe 61 is fixedly connected to the inner wall of the waste heat processing box 6 near the storage tank 1. One end of the first connecting air passage 71 located inside the waste heat processing box 6 is situated within the turbulence-inducing pipe 61, which is inclined and its outlet points towards the bottom wall of the waste heat processing box 6, thereby altering the flue gas flow direction and enhancing turbulence. Several second support legs 63 are fixedly connected to the bottom of the outer wall of the waste heat processing box 6.

[0043] The heat absorption assembly 8 is installed inside the waste heat processing box 6 and includes several mother liquor fins 81 and a serpentine bend 82. The mother liquor fins 81 are arranged at intervals and fixedly connected to the inner wall of the waste heat processing box 6 to increase the heat exchange area. The serpentine bend 82 is fixedly connected to these mother liquor fins 81 and forms a tight thermal contact with them. The inlet and outlet ends of the serpentine bend 82 pass through and are fixedly connected to the bottom and top walls of the waste heat processing box 6, respectively, for introducing the process fluid that needs to be heated.

[0044] In summary, the implementation principle of this first embodiment is as follows: First, the high-temperature, dust-laden flue gas generated by the roasting furnace enters the storage tank 1 tangentially through the inlet duct 3. Preliminary cyclone settling occurs within the conical bottom space of the storage tank 1, causing large dust particles to fall into the dust storage tank 10. The preliminarily purified high-temperature flue gas rises and is discharged from the top outlet duct 4.

[0045] Subsequently, as the high-temperature flue gas flows through the outlet duct 4, its heat is transferred through the pipe wall to the outer heat absorption box 51 and the internal phase change material 52. The phase change material 52 absorbs heat and undergoes a phase change, storing the thermal energy. At the same time, the heat spreader 53 on the outer wall of the heat absorption box 51 dissipates some of the heat to the surrounding environment through convection and radiation, achieving the first stage of waste heat recovery.

[0046] Next, the flue gas, which has been discharged through the exhaust duct 4 and has cooled down, enters the waste heat processing box 6 through the connecting assembly 7. The specific path is as follows: the flue gas flows through the first connecting duct 71 and the second connecting duct 72 in sequence. Then, the flue gas enters the turbulence pipe 61 of the waste heat processing box 6 from the end of the second connecting duct 72. After being turbulent, the flue gas impacts the bottom of the box and then diffuses upward.

[0047] During this process, the high-temperature flue gas undergoes thorough heat exchange with the heat-absorbing component device 8. The heat from the flue gas is absorbed by the mother liquor fins 81 and transferred to the closely contacting serpentine bend 82, thereby heating the process fluid (mother liquor) flowing within the serpentine bend 82, achieving a second stage of efficient and directional waste heat recovery. Finally, the cooled flue gas is discharged from the exhaust pipe 62.

[0048] The present invention and its embodiments have been described above. This description is not restrictive, and the actual structure is not limited thereto. In conclusion, if those skilled in the art, inspired by this description, design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the scope of protection of this invention.

Claims

1. A waste heat recovery device for a roasting furnace, comprising a storage tank (1) and a cover (2) connected to the top of the storage tank (1), characterized in that, Also includes: The air inlet (3) and the air outlet (4) are fixedly connected to the side wall of the storage tank (1) and the center of the cover (2), respectively. Waste heat recovery assembly (5), which is connected to the outer wall of the air outlet (4), includes a heat absorption box (51) fixedly connected to the outer wall of the air outlet (4), a phase change material (52) filled in the heat absorption box (51), and several heat spreaders (53) fixedly connected to the outer wall of the heat absorption box (51). Waste heat processing box (6) is spaced apart on one side of storage tank (1) and connected to heat absorption box (51) by connecting assembly (7); The heat absorption assembly (8) installed in the waste heat processing box (6) includes several mother liquor fins (81) and a serpentine bend (82) connected to the mother liquor fins (81).

2. The waste heat recovery device for a roasting furnace according to claim 1, characterized in that: Several of the heat spreaders (53) are located below the air intake (3), and the heat spreaders (53) are tilted toward the side of gravity.

3. The waste heat recovery device for a roasting furnace according to claim 1, characterized in that: The lower part of the inner wall of the storage tank (1) is in the shape of a conical funnel. A dust discharge pipe (9) is fixedly connected to the bottom of the storage tank (1). A dust storage tank (10) is fixedly connected to the end of the dust discharge pipe (9) on the side away from the storage tank (1).

4. The waste heat recovery device for a roasting furnace according to claim 1, characterized in that: The connecting assembly (7) includes a first connecting air passage (71) fixedly connected between the storage tank (1) and the waste heat processing box (6), and a second connecting air passage (72) fixedly connected at one end of the first connecting air passage (71) away from the waste heat processing box (6), with the end of the second connecting air passage (72) away from the first connecting air passage (71) extending into the heat absorption box (51).

5. The waste heat recovery device for a roasting furnace according to claim 4, characterized in that: An electric control valve (711) is fixedly connected to the first connecting air passage (71), and at least two first process interfaces (712). The first process interfaces (712) are spaced apart on the side of the electric control valve (711) near the storage tank (1), and a sensor (7121) is fixedly connected to each first process interface (712).

6. The waste heat recovery device for a roasting furnace according to claim 4, characterized in that: The maximum height of the phase change material (52) inside the heat absorption box (51) is lower than that of the second connecting air channel (72), and a filter screen (721) is fixedly connected to the inner wall of the second connecting air channel (72).

7. The waste heat recovery device for a roasting furnace according to claim 4, characterized in that: A baffle pipe (61) is fixedly connected to the inner wall of the waste heat processing box (6). The baffle pipe (61) is inclined and the outlet of the baffle pipe (61) points to the bottom wall of the waste heat processing box (6). An exhaust pipe (62) is fixedly connected to the top surface of the waste heat processing box (6).

8. The waste heat recovery device for a roasting furnace according to claim 1, characterized in that: The outlet end and inlet end of the serpentine bend (82) are fixedly connected to the top and bottom walls of the waste heat processing box (6), respectively.

9. The waste heat recovery device for a roasting furnace according to claim 1, characterized in that: A second process interface (31) is fixedly connected to the outer wall of the air intake (3), and a detection element (32) is fixedly connected inside the second process interface (31).

10. A waste heat recovery device for a roasting furnace according to claim 1, characterized in that: Several first legs (12) and second legs (63) are fixedly connected to the outer walls of the storage tank (1) and the waste heat processing box (6), respectively.

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