Circulating device for recycling tail gas waste heat of electric calcining furnace

Abstract

The circulating device comprises a combustion system and a heat conduction oil system, and the combustion system is sequentially provided with a combustion chamber, an organic heat carrier heat exchanger, a radiator, a dust remover, a high-temperature variable-frequency speed regulation induced draft fan and a chimney according to the tail gas combustion process sequence; the heat conduction oil system is divided into an oil conveying system, an oil return system and a nitrogen sealing device. According to the combustion system and the heat conduction oil system, the tail gas generated in the electric forging furnace is exhausted into the atmosphere after being treated by the combustion system, the influence on the environment is avoided, the heat conduction oil system is arranged between the combustion system and other energy consumption equipment, heat in the original tail gas is absorbed and then transmitted to other energy consumption equipment for use, and the heat conduction efficiency is improved. The problem that in the prior art, after tail gas generated by the electric forging furnace is ignited, high-temperature heat in original tail gas is wasted due to air emission is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of waste heat recovery of electric calcining furnace flue gas, in particular to a circulation device for waste heat recovery of electric calcining furnace tail gas. Background Art

[0002] During the process of preparing corresponding products by an electric forging furnace, flue gas with a high explosion hazard level, a small flue gas volume, and a high flue gas temperature is generated. Due to harmful substances such as hydrogen, methane, and carbon monoxide contained in the flue gas, the emission of the flue gas will have an impact on the environment and human health.

[0003] In the prior art, for the tail gas generated by an electric forging furnace, the tail gas is usually ignited and discharged into the sky. However, in this process, the high-temperature energy in the original flue gas is wasted. Summary of the Utility Model

[0004] The purpose of the utility model is to solve the problem in the prior art that the high-temperature heat in the original tail gas is wasted by igniting the tail gas generated by an electric forging furnace and discharging it into the sky.

[0005] To achieve the above purpose, the present application proposes a circulation device for waste heat recovery of electric calcining furnace tail gas, including: a combustion system and a heat transfer oil system.

[0006] Among them, the high-temperature flue gas generated from the electric calcining furnace is finally discharged into the atmosphere after being processed by the combustion system.

[0007] The heat transfer oil system is arranged between the combustion system and the energy-consuming equipment. The energy-consuming equipment includes: an air heat exchanger, workshop equipment, and the main oil supply pipeline of the original system.

[0008] The combustion system is successively provided with: a combustion chamber, an organic heat carrier heat exchanger, a radiator, a dust collector, a high-temperature variable-frequency speed-regulating induced draft fan, and a chimney according to the tail gas combustion process sequence.

[0009] The heat transfer oil system is divided into an oil delivery system, an oil return system, and a nitrogen sealing device.

[0010] The combustion system and the heat transfer oil system of the present application can reach the tail gas emission standard after processing the tail gas generated in the electric forging furnace through the combustion system, avoiding the impact of the tail gas on the environment. At the same time, a heat transfer oil system is arranged between the combustion system and other energy-consuming equipment to absorb the heat in the original tail gas through the heat transfer oil system and transfer it to other energy-consuming equipment for use, solving the problem in the prior art that the high-temperature heat in the original tail gas is wasted by igniting the tail gas generated by the electric forging furnace and discharging it into the sky.

[0011] As an improvement of the above combustion chamber of the present application, in order to ensure the safety during the operation of the combustion chamber, inspection holes, fire viewing holes, and explosion-proof doors are provided on the combustion chamber.

[0012] As an improvement to the above radiator of the present application, in order to increase the diversity of heat dissipation methods and ensure the best heat dissipation efficiency, the radiator can be an air-cooled radiator or a liquid-cooled radiator.

[0013] As an improvement to the above oil transportation system of the present application, in order to maintain the stability and safety of the oil transportation system and ensure the use efficiency of high-temperature heat-conducting oil, the oil transportation system includes: an oil distribution cylinder, an oil collection cylinder, and an expansion tank, which are set up in sequence according to the oil transportation route.

[0014] Furthermore, in order to increase the flexibility of the oil distribution routes, the oil distribution cylinder includes: a first oil distribution path, a second oil distribution path, a third oil distribution path, a fourth oil distribution path, and a reserved port. Among them, the output end of the first oil distribution path is connected to the input end of the air heat exchanger, the output end of the second oil distribution path is connected to the input end of the workshop equipment, and the output end of the third oil distribution path is connected to the input end of the main oil supply pipeline of the original system.

[0015] Furthermore, in order to increase the flexibility of the oil return routes, the oil collection cylinder includes: a first oil return path, a second oil return path, a third oil return path, a fourth oil return path, and a reserved port. Among them, the output end of the first oil return path is connected to the output end of the air heat exchanger, the output end of the second oil return path is connected to the output end of the workshop equipment, and the output end of the third oil return path is connected to the output end of the main oil supply pipeline of the original system.

[0016] As an improvement to the above oil return system of the present application, in order to maintain the stability and safety of the oil return system and ensure the use efficiency of high-temperature heat-conducting oil, the oil return system includes: a hot oil storage tank, a Y-type filter, an injection oil pump, a cartridge filter, an oil-gas separator, and a hot oil circulation pump, which are set up in sequence according to the oil return route.

[0017] Furthermore, in order to achieve the compensation effect of the oil volume between the oil distribution cylinder and the oil collection cylinder, the fourth oil distribution path is connected to the fourth oil return path, and an electric valve interlocked with the flow rate is set between the two.

[0018] As an improvement to the above expansion tank of the present application, in order to stabilize the operating pressure of the heat-conducting oil system and at the same time help the system to dehydrate and exhaust steam, the expansion tank is set at the highest point of the heat-conducting oil system, and the expansion tank is provided with a low liquid level alarm and an over-temperature alarm.

[0019] As an improvement to the above nitrogen sealing device of the present application, in order to prevent high-temperature heat-conducting oil from contacting with air and oxidizing, the nitrogen sealing device is placed at the upper end of the hot oil storage tank.

[0020] The beneficial effects of the present application are as follows:

[0021] 1. The circulating device for recovering waste heat from the tail gas of the electric calcining furnace in this application, by setting up a combustion system and a heat transfer oil system, after the tail gas generated in the electric forging furnace is treated by the combustion system, it can meet the tail gas emission standards, avoiding the impact of the tail gas on the environment. At the same time, a heat transfer oil system is set between the combustion system and other energy-consuming equipment, absorbing the heat in the original tail gas through the heat transfer oil system and transferring it to other energy-consuming equipment for use, solving the problem in the prior art that the high-temperature heat in the original tail gas is wasted when the tail gas generated by the electric calcining furnace is burned and discharged into the sky.

[0022] 2. The combustion chamber of this application is provided with inspection holes, sight holes and explosion-proof doors for inspecting the combustion chamber, which can check the operation stability of the combustion chamber during its working process to ensure safety.

[0023] 3. In the heat transfer oil system of this application, multiple circulation paths and spare interfaces are set. While meeting the usage requirements of different equipment, the main oil supply pipeline in the original system can be introduced into the existing heat transfer oil system, and then by setting corresponding oil quantity compensation devices and circulation paths, the stability of the operation of the whole system can be stabilized.

[0024] 4. A nitrogen sealing device is set at the upper end of the hot oil storage tank of this application. The expansion tank and the oil storage tank are connected through an overflow pipe. The nitrogen sealing device can be opened or closed according to the state of the heat transfer oil in the hot oil storage tank and the pressure inside the hot oil storage tank to complete the compensation function for the heat transfer oil in the hot oil storage tank.

[0025] 5. A dust collector and a radiator are set in the combustion system of this application, which can dust and cool the tail gas after combustion. Compared with the tail gas discharged by the traditional method, the tail gas finally generated by using this system is more environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0027] Figure 1 It is a schematic structural diagram of a circulating device for recovering waste heat from the tail gas of an electric calcining furnace in an embodiment of this application;

[0028] Figure 2 It is a schematic structural diagram of a heat transfer oil system in an embodiment of this application;

[0029] Explanation of the reference numerals in the drawings:

[0030] 1. Combustion system; 11. Combustion chamber; 111. Inspection hole; 112. Fire viewing hole; 113. Explosion-proof door; 12. Organic heat carrier heat exchanger; 13. Radiator; 14. Dust collector; 15. High-temperature variable-frequency speed regulation induced draft fan; 16. Chimney;

[0031] 2. Heat-conducting oil system; 21. Oil transmission system; 211. Oil distribution cylinder; 2111. First oil distribution path; 2112. Second oil distribution path; 2113. Third oil distribution path; 2114. Fourth oil distribution path; 2115. Reserved port; 212. Oil collecting cylinder; 2121. First oil return path; 2122. Second oil return path; 2123. Third oil return path; 2124. Fourth oil return path; 213. Electric valve; 214. Expansion tank; 22. Oil return system; 221. Hot oil storage tank; 222. Y-type filter; 223. Oil injection pump; 224. Cartridge filter; 225. Oil-gas separator; 226. Hot oil circulation pump; 23. Nitrogen sealing device;

[0032] 3. Electric forging furnace;

[0033] 4. Energy-consuming equipment; 41. Air heat exchanger; 42. Workshop equipment; 43. Main oil supply pipeline of the original system. Detailed implementation manners

[0034] Next, embodiments of the technical solution of the present application will be described in detail. The following embodiments are only used to illustrate the technical solution of the present application more clearly, so they are only examples and cannot be used to limit the protection scope of the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other. Figures 1-2

[0035] Figure 1 As schematically shows a circulating device for recovering waste heat from the tail gas of an electric forging furnace of the present application, including: a combustion system 1 and a heat-conducting oil system 2,

[0036] wherein, the high-temperature flue gas generated from the electric forging furnace 3 is finally discharged into the atmosphere after being processed by the combustion system 1,

[0037] The heat-conducting oil system 2 is arranged between the combustion system 1 and the energy-consuming equipment 4. The energy-consuming equipment 4 includes: an air heat exchanger 41, workshop equipment 42, and the main oil supply pipeline 43 of the original system

[0038] The combustion system 1 is successively provided with: a combustion chamber 11, an organic heat carrier heat exchanger 12, a radiator 13, a dust collector 14, a high-temperature variable-frequency speed regulation induced draft fan 15, and a chimney 16 in accordance with the tail gas combustion process sequence;

[0039] The heat-conducting oil system 2 is divided into an oil transmission system 21, an oil return system 22, and a nitrogen sealing device 23.

[0040] In an embodiment of the present application, the combustion system 1 reprocesses the tail gas generated by the electric forging furnace 3. After completing the heat exchange with the heat transfer oil system 2, it is cooled by the radiator 13 and dust is removed by the dust collector 14, and then is transported to the chimney 16 by the high-temperature variable-frequency adjustable-speed induced draft fan 15 and finally discharged into the air. The heat transfer oil system 2 transfers the heat obtained from the heat exchange to the energy-consuming equipment 4 for heating the whole plant and the use of various equipment.

[0041] In the prior art, when traditional carbon production enterprises process the tail gas generated by the roasting furnace, they usually ignite the tail gas and discharge it into the sky. This method of processing tail gas wastes energy in two aspects. On the one hand, it is the energy required to ignite the tail gas, and on the other hand, the high temperature contained in the original tail gas is directly discharged into the atmosphere without being recycled.

[0042] In this embodiment, the combustion system 1 is used to mix the unburned tail gas in the electric forging furnace 3 with oxygen and burn it fully, and after heat exchange treatment of the fully burned tail gas, it is cooled by the radiator 13 and dust is removed by the dust collector 14, and then the high-temperature variable-frequency adjustable-speed induced draft fan 15 pumps the tail gas to the chimney 16 and finally discharges it into the air; the heat transfer oil system 2 is used to transfer the heat recovered after heat exchange to the energy-consuming equipment 4 through the heat transfer oil. Specifically, it is transported to the air heat exchanger 41 for heating use, transported to the workshop equipment 42 for use, and transported to the original system's oil supply main pipeline 43 for use, and can also be used as a backup heat source for the production system, solving the problem in the prior art that the high-temperature heat in the tail gas generated by the electric forging furnace is wasted when it is ignited and discharged into the air.

[0043] Continue to refer to Figure 1 In a further embodiment, an inspection hole 111, a fire viewing hole 112 and an explosion-proof door 113 are provided on the combustion chamber 11. Specifically, the combustion furnace is provided with an inspection hole, a fire viewing hole and an explosion-proof door for inspecting the combustion chamber. During the operation of the combustion chamber 11, the combustion condition of the tail gas inside the combustion chamber 11 is monitored.

[0044] Optionally, a flue gas flowmeter is provided in the pipeline connecting the electric forging furnace 3 and the combustion chamber 11 to monitor the flue gas flow rate entering the combustion chamber 11. In this way, the combustion chamber 11 is set with different volumes according to the size of the entering flue gas flow rate so that the flue gas can be burned fully.

[0045] Optionally, the radiator 13 can be an air-cooled radiator or a liquid-cooled radiator. Specifically, the radiator can select different forms of heat dissipation methods according to different installation sites.

[0046] Continue to refer to Figure 2 In a further embodiment, the oil transportation system 21 includes: an oil distribution cylinder 211, an oil collection cylinder 212, an electric valve 213, and an expansion tank 214 arranged in sequence according to the oil transportation route.

[0047] Specifically, the distribution oil cylinder 211 and the collecting oil cylinder 212 are used to divert and collect the heat-conducting oil that has completed heat exchange. The electric valve 213 installed between the distribution oil cylinder 211 and the collecting oil cylinder 212 is used to adjust the heat-conducting oil in the distribution oil cylinder 211 and the collecting oil cylinder 212 to reach a balanced relationship.

[0048] Furthermore, the expansion tank is used for compensating the volume change of the heat-conducting oil due to temperature changes, thereby stabilizing the operating pressure of the heat-conducting oil system. At the same time, it can also help the system to dehydrate and exhaust air. Therefore, the expansion tank is set at the highest point of the heat-conducting oil system, and the expansion tank is provided with a low liquid level alarm (liquid level lower than 200 mm) and an over-temperature alarm (70 °C).

[0049] Continue to refer to Figure 2 , in a further embodiment, the distribution oil cylinder 211 includes: a first oil distribution path 2111, a second oil distribution path 2112, a third oil distribution path 2113, a fourth oil distribution path 2114, and a reserved port 2115. Among them, the output end of the first oil distribution path 2111 is connected to the input end of the air heat exchanger 41, the output end of the second oil distribution path 2112 is connected to the input end of the workshop equipment 42, and the output end of the third oil distribution path 2113 is connected to the input end of the original system oil supply main pipeline 43.

[0050] Continue to refer to Figure 2 , in a further embodiment, the collecting oil cylinder 212 includes: a first oil return path 2121, a second oil return path 2122, a third oil return path 2123, a fourth oil return path 2124, and a reserved port 2115. Among them, the output end of the first oil return path 2121 is connected to the output end of the air heat exchanger 41, the output end of the second oil return path 2122 is connected to the output end of the workshop equipment 42, and the output end of the third oil return path 2123 is connected to the output end of the original system oil supply main pipeline 43.

[0051] Specifically, the first oil distribution path 2111, the air heat exchanger 41, and the first oil return path 2121 form the first heat-conducting oil circulation path to dissipate heat from the air heat exchanger 41 and complete the heating of the whole plant; the second oil distribution path 2112, the workshop equipment 42, and the second oil return path 2122 form the second heat-conducting oil circulation path for the use of the workshop equipment 42; the third oil distribution path 2113, the original system oil supply main pipeline 43, and the third oil return path 2123 form the third heat-conducting oil circulation path to complete the heat exchange between the heat-conducting oil and the equipment in the original system; the reserved port 2115 is temporarily kept closed and reserved for future expansion or maintenance, and can be flexibly opened and connected to a new oil distribution path according to actual needs.

[0052] Continue to refer to Figure 2, in a further embodiment, the oil return system 22 includes, arranged in sequence along the oil return route: a hot oil storage tank 221, a Y-type filter 222, an injection oil pump 223, a cartridge filter 224, an oil-gas separator 225, and a hot oil circulation pump 226. After the hot oil returns from the energy-consuming equipment, it first enters the hot oil storage tank 221 for preliminary storage, and then undergoes processes such as filtration and degassing. Finally, it is pumped by the hot oil circulation pump 226 to the oil distribution cylinder 211 for redistribution. At the same time, the hot oil storage tank is mainly used to store the heat transfer oil discharged from the high-level tank, the hot oil furnace, and the system. During normal operation, a certain amount (about 300 mm) of heat transfer oil should be stored. When the system is short of oil, heat transfer oil can be supplemented into the system. The injection oil pump is used to automatically supplement heat transfer oil to the system (high-level tank) during normal and stable operation of the system. During commissioning and maintenance, the injection oil pump has the following functions by switching valves: 1. Inject the external heat transfer oil into the oil storage tank; 2. Inject the heat transfer oil in the low-level tank into the high-level tank; 3. Return the heat transfer oil in the equipment such as the circulation pump and filter that need to be repaired to the oil storage tank.

[0053] Optionally, the hot oil circulation pump is the power for the forced circulation of the heat transfer oil system. Two or more hot oil circulation pumps can be configured, one for daily use, and the others for standby to avoid the heat transfer oil system from stopping working due to unexpected situations.

[0054] Continue to refer to Figure 2 , in a further embodiment, the fourth oil distribution path 2114 is connected to the fourth oil return path 2124, and an electric valve 213 interlocked with the flow rate is provided therebetween. Specifically, the electric valve 213 interlocked with the flow rate and the fourth oil distribution path 2114 and the fourth oil return path 2124 form a heat transfer oil circulation path between the oil distribution cylinder 211 and the oil collection cylinder 212, and at the same time detect the flow rate difference between the oil distribution cylinder 211 and the oil collection cylinder 212 to timely adjust the oil level difference between the oil distribution cylinder 211 and the oil collection cylinder 212.

[0055] Continue to refer to Figure 2 , in a further embodiment, the expansion tank 214 is arranged at the highest point of the heat transfer oil system 2, and the expansion tank 214 is provided with a low liquid level alarm and an over-temperature alarm.

[0056] Continue to refer to Figure 2, in a further embodiment, the nitrogen sealing device 23 is placed at the upper end of the hot oil storage tank 221. Specifically, the function of the nitrogen sealing device is to prevent the high-temperature heat transfer oil from contacting with air and oxidizing. The nitrogen sealing device is placed at the upper end of the oil storage tank. The expansion tank and the oil storage tank are connected through an overflow pipe. After the system is debugged normally, the vent valves of the expansion tank and the oil storage tank are closed and the nitrogen sealing device starts to work. When the system is short of oil, the high-level tank supplies oil to the system, the pressure in the oil storage tank decreases, the nitrogen supply valve opens to supply oil to the storage tank. When light components are discharged from the system or the hot oil in the system expands, the pressure in the storage tank increases, the nitrogen relief valve automatically opens, the pressure in the pipe decreases to the set pressure, and the nitrogen relief valve automatically closes. The opening pressure of the nitrogen supply valve is 3 kPa, and the opening pressure of the nitrogen relief valve is 5 kPa.

[0057] In the description of the embodiments of the present application, the orientation or positional relationship indicated by technical terms such as "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the embodiments of the present application.

[0058] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "set", "provided with", "connected", "installed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or equivalently replace some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A circulating device for waste heat recovery of the tail gas of an electric calcining furnace, comprising: Combustion system (1) and heat transfer oil system (2), wherein, the high-temperature flue gas generated from the electric calcining furnace (3) is finally discharged into the atmosphere after being processed by the combustion system (1), the heat transfer oil system (2) is arranged between the combustion system (1) and the energy-consuming equipment (4), and the energy-consuming equipment (4) includes: an air heat exchanger (41), workshop equipment (42), and the main oil supply pipeline (43) of the original system It is characterized in that the combustion system (1) is successively provided with a combustion chamber (11), an organic heat carrier heat exchanger (12), a radiator (13), a dust collector (14), a high-temperature variable-frequency speed regulating induced draft fan (15), and a chimney (16) in accordance with the tail gas combustion process sequence; The heat transfer oil system (2) is divided into an oil transmission system (21), an oil return system (22), and a nitrogen sealing device (23).

2. The circulation device according to claim 1, characterized in that, The combustion chamber (11) is provided with an inspection hole (111), a fire viewing hole (112), and an explosion-proof door (113).

3. The circulation device according to claim 1, characterized in that, The radiator (13) can be an air-cooled radiator or a liquid-cooled radiator.

4. The circulation device according to claim 1, characterized in that, The oil transmission system (21) includes, successively arranged in the oil transmission route: an oil separation cylinder (211), an oil collection cylinder (212), an electric valve (213), and an expansion tank (214).

5. The circulation device according to claim 4, characterized in that, The oil separation cylinder (211) includes: a first oil separation path (2111), a second oil separation path (2112), a third oil separation path (2113), a fourth oil separation path (2114), and a reserved port (2115). Among them, the output end of the first oil separation path (2111) is connected to the input end of the air heat exchanger (41), the output end of the second oil separation path (2112) is connected to the input end of the workshop equipment (42), and the output end of the third oil separation path (2113) is connected to the input end of the main oil supply pipeline (43) of the original system.

6. The circulation device according to claim 5, characterized in that The oil collection cylinder (212) includes: a first oil return path (2121), a second oil return path (2122), a third oil return path (2123), a fourth oil return path (2124), and a reserved port (2115). Among them, the output end of the first oil return path (2121) is connected to the output end of the air heat exchanger (41), the output end of the second oil return path (2122) is connected to the output end of the workshop equipment (42), and the output end of the third oil return path (2123) is connected to the output end of the main oil supply pipeline (43) of the original system.

7. The circulating device according to claim 1, characterized in that, The oil return system (22) includes, successively arranged in the oil return route: a hot oil storage tank (221), a Y-type filter (222), an injection oil pump (223), a cartridge filter (224), an oil-gas separator (225), and a hot oil circulation pump (226).

8. The circulating device according to claim 6, wherein The fourth oil separation path (2114) is connected to the fourth oil return path (2124), and an electric valve (213) interlocked with the flow rate is arranged between the two.

9. The circulation device according to claim 4, characterized in that The expansion tank (214) is arranged at the highest point of the heat transfer oil system (2), and the expansion tank (214) is provided with a low liquid level alarm and an over-temperature alarm.

10. The circulation device according to claim 1, characterized in that, The nitrogen sealing device (23) is placed at the upper end of the hot oil storage tank (221).

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