Reduction furnace heat recovery system

Abstract

This application provides a heat recovery system for a reduction furnace. The system includes a reduction furnace and a first circulation unit. The reduction furnace includes a furnace cylinder, a chassis, and a first tail gas jacket, with a first cooling pipe correspondingly installed in the jacket. The first circulation unit includes a first flash evaporator. The liquid outlet pipes of the first cooling pipe and the chassis are both connected to the liquid inlet of the furnace cylinder, and the liquid outlet of the furnace cylinder is connected to the first flash evaporator. The first flash evaporator is connected to both the first cooling pipe and the liquid inlet pipe of the chassis. This heat recovery system solves the problem of low heat recovery efficiency in reduction furnaces, leading to high energy consumption in regeneration processes.

Description

Technical Field

[0001] This application relates to the field of polysilicon production technology, specifically to a heat recovery system for a reduction furnace. Background Technology

[0002] With the continuous development of the new energy industry, domestic polysilicon production technology has also developed rapidly. Currently, the mainstream polysilicon production process in China adopts the modified Siemens process, and the scale of the equipment is becoming increasingly larger. In the modified Siemens process, over 70% of the energy consumption comes from the reduction furnace. The reduction furnace generates a large amount of waste heat during operation. This waste heat can be used to power polysilicon cold hydrogenation, distillation, and tail gas recovery units. Therefore, high-quality recovery of the waste heat generated by the reduction furnace is beneficial for saving energy consumption.

[0003] In related technologies, heat is absorbed from the tail gas jacket by circulating water to form high-temperature circulating water. This high-temperature circulating water is then depressurized and flash-evaporated in a flash tank to generate steam and low-temperature circulating water. The steam can be collected to provide energy for devices such as polycrystalline silicon cold hydrogenation, distillation, and tail gas recovery. The low-temperature circulating water can be reused to absorb heat from the tail gas jacket and circulate, thereby converting the heat generated by the tail gas jacket into energy that can be provided to other devices.

[0004] However, the relevant technologies have limited utilization of the heat inside the exhaust jacket, making it difficult to fully utilize the heat inside the exhaust jacket, resulting in low recovery efficiency and high production energy consumption. Summary of the Invention

[0005] This application provides a heat recovery system for a reduction furnace, which can solve the problem of low heat recovery efficiency in the reduction furnace, resulting in high energy consumption in the regeneration process.

[0006] This application provides a heat recovery system for a reduction furnace, comprising:

[0007] A reduction furnace, comprising a furnace cylinder, a chassis, and a first tail gas jacket, wherein a first cooling pipe is correspondingly provided on the first tail gas jacket;

[0008] The first circulation unit includes a first flash evaporator, the first cooling pipe and the liquid outlet pipe of the chassis are both connected to the liquid inlet of the furnace cylinder, the liquid outlet of the furnace cylinder is connected to the first flash evaporator, and the first flash evaporator is connected to the first cooling pipe and the liquid inlet pipe of the chassis respectively.

[0009] The reduction furnace heat recovery system provided in this application allows the first circulation unit to transfer the heat from the chassis and the first tail gas jacket to the furnace drum, effectively utilizing the heat generated by the first tail gas jacket and the chassis. Furthermore, the heat from the first tail gas jacket and the chassis, after being mixed with the heat in the reduction furnace drum and then flash-evaporated, can help obtain high-grade steam byproducts, thereby improving the recovery efficiency of the waste heat from the reduction furnace and thus more effectively achieving a balance between steam supply and demand, and reducing production energy consumption.

[0010] According to one embodiment of this application, the first circulation unit further includes a first parallel pipeline, which includes a first branch pipe and a second branch pipe. The first cooling pipe is connected to the liquid inlet of the furnace barrel through the first branch pipe, and the liquid outlet pipe of the chassis is connected to the liquid inlet of the furnace barrel through the second branch pipe.

[0011] According to one embodiment of this application, the first circulation unit further includes a second parallel pipeline, the second parallel pipeline including a third branch pipe and a fourth branch pipe, the first flash evaporator being connected to the first cooling pipe through the third branch pipe, and the first flash evaporator being connected to the liquid inlet pipe of the chassis through the fourth branch pipe.

[0012] According to one embodiment of this application, the first flash evaporator includes a primary flash tank and a secondary flash tank, wherein the primary flash tank generates first steam and a first coolant, and the first steam enters a steam pipeline network;

[0013] The secondary flash tank continues to flash the first coolant to generate second steam and second coolant, and the second steam enters the steam pipeline network;

[0014] The second coolant enters the first cooling pipe and the inlet pipe of the chassis through the third branch pipe and the fourth branch pipe respectively, and circulates.

[0015] According to one embodiment of this application, the reduction furnace further includes a second tail gas jacket, the second tail gas jacket is correspondingly provided with a second cooling pipe, and the reduction furnace heat recovery system further includes a second circulation unit;

[0016] The second circulation unit includes a second flash evaporator, and the second cooling pipe is connected to the second flash evaporator. The second flash evaporator generates a third steam and a third coolant. The third steam enters the steam network, and the third coolant flows back into the second cooling pipe and circulates.

[0017] According to one embodiment of this application, the first circulation unit further includes a first liquid circulation pump, which is disposed between the secondary flash tank and the second parallel pipeline, and the first liquid circulation pump introduces the second coolant into the third branch pipe and the fourth branch pipe respectively.

[0018] The second circulation unit further includes a second liquid circulation pump, which is connected to the second flash evaporator, and the second liquid circulation pump introduces the third coolant into the second cooling pipe.

[0019] According to one embodiment of this application, in the first circulation unit, the furnace cylinder, the chassis, the first cooling pipe, the first-stage flash tank, and the second-stage flash tank share a single first liquid circulation pump.

[0020] According to one embodiment of this application, the second exhaust gas jacket is located between the furnace cylinder and the first exhaust gas jacket.

[0021] According to one embodiment of this application, the first-stage flash tank is a steam flash tank with a steam pressure of 0.4 MPaG-0.6 MPaG; the second-stage flash tank is a steam flash tank with a steam pressure of 0.2 MPaG-0.3 MPaG; and the second flash evaporator is a steam flash tank with a steam pressure of 0.8 MPaG-1.1 MPaG.

[0022] According to one embodiment of this application, the temperature at which the gas in the second exhaust gas jacket enters the first exhaust gas jacket is 210-230°C.

[0023] The gas temperature at the end of the first exhaust gas jacket furthest from the second exhaust gas jacket is 150°C.

[0024] In addition to the technical problems solved by the embodiments of the present invention, the technical features constituting the technical solutions, and the beneficial effects brought about by the technical features of these technical solutions described above, other technical problems that can be solved by the reduction furnace heat recovery system provided by the embodiments of the present invention, other technical features included in the technical solutions, and the beneficial effects brought about by these technical features will be further described in detail in the specific embodiments. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0026] Figure 1 This is a schematic diagram of the structure of a reduction furnace heat recovery system according to an embodiment of this application.

[0027] Explanation of reference numerals in the attached figures:

[0028] 100-Reduction Furnace Heat Recovery System;

[0029] 110 - Reduction Furnace;

[0030] 111-Furnace barrel; 111a-Liquid inlet; 111b-Liquid outlet;

[0031] 112-Chassis; 112a-Outlet pipe; 112b-Inlet pipe;

[0032] 113 - First exhaust gas jacket;

[0033] 114 - Second exhaust gas jacket;

[0034] 115 - First cooling pipe;

[0035] 116 - Second cooling pipe;

[0036] 120 - First cycle unit;

[0037] 121 - First flash evaporator; 1211 - First-stage flash tank; 1212 - Second-stage flash tank;

[0038] 122 - First parallel pipe; 1221 - First branch pipe; 1222 - Second branch pipe; 1223 - First connecting pipe;

[0039] 123 - Second parallel pipe; 1231 - Third branch pipe; 1232 - Fourth branch pipe; 1233 - Second connecting pipe;

[0040] 124 - First liquid circulation pump;

[0041] 130 - Second cycle unit;

[0042] 131 - Second flash evaporator; 132 - Second liquid circulation pump.

[0043] The accompanying drawings have illustrated specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to specific embodiments. Detailed Implementation

[0044] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims. Clearly, the described embodiments are only a portion, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0045] Currently, the main process technology for producing polysilicon is the modified Siemens process: high-purity trichlorosilane, after purification, is mixed with hydrogen in a certain proportion and then introduced into a polysilicon reduction furnace under specific temperature and pressure. A deposition reaction occurs on a high-temperature silicon core powered by an electric current, generating polysilicon and producing high-temperature reduction tail gas. The tetrachlorosilane, trichlorosilane, hydrogen chloride, and hydrogen in the reduction tail gas can be cooled, separated, and recovered for recycling back into the raw materials.

[0046] In the polysilicon production process, the reduction furnace can heat the silicon core to over 1000 degrees Celsius using electrical energy, generating a large amount of heat. The exhaust gas temperature from the reduction furnace can reach 600 degrees Celsius. This heat can be recovered from the reduction furnace to generate steam. Steam is consumed during the operation of polysilicon cold hydrogenation, distillation, and exhaust gas recovery processes. Therefore, the steam generated from the heat recovery in the reduction furnace can be used in these processes, with the remaining steam considered waste heat. This waste heat needs to be cooled by a refrigerant before being released. Ideally, the steam generated from the heat recovery in the reduction furnace could be entirely used to power the polysilicon cold hydrogenation, distillation, and exhaust gas recovery processes, eliminating the need for additional steam production equipment and waste heat treatment with a refrigerant, thus reducing refrigerant consumption.

[0047] The reduction furnace heat recovery system can recover the waste heat from the reduction furnace in a high-quality manner for use in other devices such as cold hydrogenation, distillation, and tail gas recovery of polysilicon. This enables the effective utilization of thermal energy and reduces refrigerant consumption, which is of great significance for reducing the energy consumption of the entire polysilicon production process.

[0048] In related technologies, high-temperature circulating water can be generated by absorbing heat from the tail gas jacket. This high-temperature circulating water is then subjected to reduced pressure and flash evaporation in a flash tank to produce steam and low-temperature circulating water. The steam can be collected to provide energy for other devices such as polycrystalline silicon cold hydrogenation, distillation, and tail gas recovery. The low-temperature circulating water can be reused to absorb heat from the tail gas jacket and circulate, thereby converting the heat generated by the tail gas jacket into energy that can be provided to other devices.

[0049] However, the relevant technologies have limited utilization of the heat inside the exhaust jacket, making it difficult to fully utilize the heat inside the exhaust jacket, resulting in low recovery efficiency and high production energy consumption.

[0050] Based on the aforementioned technical problems, the applicant has improved the structure of the existing reduction furnace heat recovery system. In the reduction furnace heat recovery system of this application, the first circulation unit can first transfer the heat from the chassis and the heat in the first tail gas jacket to the furnace drum, so as to effectively utilize the heat generated by the first tail gas jacket and the chassis. Furthermore, the heat in the first tail gas jacket and the chassis, after being mixed with the heat in the furnace drum of the reduction furnace and then flash-evaporated, can help obtain high-grade steam by-product output, thereby improving the waste heat recovery efficiency of the reduction furnace, thus more effectively achieving the balance between steam supply and demand and reducing production energy consumption.

[0051] The heat recovery system for the reduction furnace provided in this application is described below with reference to the accompanying drawings and specific embodiments.

[0052] See Figure 1 As shown, the reduction furnace heat recovery system 100 of this application embodiment may include a reduction furnace 110 and a first circulation unit 120.

[0053] The reduction furnace 110 may include a furnace cylinder 111, a chassis 112, and a first exhaust gas jacket 113. The first exhaust gas jacket 113 may be equipped with a first cooling pipe 115. The first circulation unit 120 includes a first flash evaporator 121. The liquid outlet pipes 112a of the first cooling pipe 115 and the chassis 112 are both connected to the liquid inlet 111a of the furnace cylinder 111. The liquid outlet 111b of the furnace cylinder 111 may be connected to the first flash evaporator 121. The first flash evaporator 121 is connected to both the first cooling pipe 115 and the liquid inlet pipe 112b of the chassis 112.

[0054] The first cooling pipe 115 contains a circulating fluid. This circulating fluid absorbs heat from the first exhaust gas jacket 113 to form a high-temperature circulating fluid. The first circulation unit 120 can guide the high-temperature circulating fluid from the first cooling pipe 115 into the furnace drum 111. Furthermore, the high-temperature circulating fluid in the outlet pipe 112a of the chassis 112 can also be guided into the furnace drum 111. Therefore, it is easy to understand that the heat generated in the first exhaust gas jacket 113 and the chassis 112 can be transferred to the furnace drum 111, achieving efficient utilization of the heat generated in the first exhaust gas jacket 113 and the heat from the chassis 112.

[0055] The high-temperature circulating liquid in the first cooling pipe 115 and the high-temperature circulating liquid in the outlet pipe 112a of the chassis 112 can form a high-temperature mixture after entering the high-temperature furnace 111. The high-temperature mixture can be introduced into the first flash evaporator 121 through the outlet 111b of the furnace 111. Since the heat generated in the first tail gas jacket 113 and the heat of the chassis 112 are also introduced into the furnace 111, the first flash evaporator 121 can obtain higher-grade steam and cooled mixture by depressurized flash evaporation of the high-temperature mixture. The steam can be collected and sent to the steam network to meet the energy needs of other devices. The cooled mixture can be returned to the inlet pipes 112b of the first cooling pipe 115 and the chassis 112 respectively to absorb the heat generated in the first tail gas jacket 113 and the chassis 112 again and circulate. This continuously converts the heat generated by the reduction furnace 110 into steam to provide energy for other devices, which is beneficial to improving the waste heat recovery efficiency of the reduction furnace 110 and reducing production energy consumption.

[0056] See also some of the possible implementation methods. Figure 1 As shown, the first circulation unit 120 in this embodiment may further include a first parallel pipeline 122. The first parallel pipeline 122 may include a first branch pipe 1221 and a second branch pipe 1222. The first cooling pipe 115 is connected to the liquid inlet 111a of the furnace barrel 111 through the first branch pipe 1221. The liquid outlet pipe 112a of the chassis 112 is connected to the liquid inlet 111a of the furnace barrel 111 through the second branch pipe 1222.

[0057] In this embodiment, the first branch pipe 1221 and the second branch pipe 1222 can be connected in parallel. The first branch pipe 1221 can transfer the heat generated in the first exhaust gas jacket 113 to the furnace barrel 111. The second branch pipe 1222 can transfer the heat in the chassis 112 to the furnace barrel 111 via the liquid outlet pipe 112a.

[0058] In some examples, the first circulation unit 120 may further include a first connecting pipe 1223. Both the first branch pipe 1221 and the second branch pipe 1222 can be connected to the first connecting pipe 1223, and the first connecting pipe 1223 is connected to the liquid inlet 111a of the furnace drum 111. Therefore, the high-temperature circulating liquid in the first branch pipe 1221 and the high-temperature circulating liquid in the second branch pipe 1222 can be mixed in a portion of the first connecting pipe 1223 before entering the furnace drum 111.

[0059] See also some of the possible implementation methods. Figure 1As shown, the first circulation unit 120 in this embodiment further includes a second parallel pipeline 123. The second parallel pipeline 123 includes a third branch pipe 1231 and a fourth branch pipe 1232. The first flash evaporator 121 is connected to the first cooling pipe 115 through the third branch pipe 1231, and the first flash evaporator 121 is connected to the liquid inlet pipe 112b of the chassis 112 through the fourth branch pipe 1232.

[0060] The cooling mixture formed by flash evaporation in the first flash evaporator 121 can flow back to the first cooling pipe 115 and the inlet pipe 112b of the chassis 112 through the third branch pipe 1231 and the fourth branch pipe 1232, respectively. The third branch pipe 1231 can introduce the cooled mixture into the first cooling pipe 115, i.e., the (low-temperature) circulating liquid. The circulating liquid can absorb heat from the first exhaust jacket 113 again to form a high-temperature circulating liquid, which can then transfer heat to the furnace barrel 111 again and continue circulating. The fourth branch pipe 1232 can introduce the cooled mixture into the chassis 112 through the inlet pipe 112b of the chassis 112, and then transfer the heat from the chassis 112 to the furnace barrel 111 and continue circulating.

[0061] In some examples, the first circulation unit 120 may also include a second connecting pipe 1233. The third branch pipe 1231 and the fourth branch pipe 1232 may both be connected to the second connecting pipe 1233, and the second connecting pipe 1233 is connected to the first flash evaporator 121. Therefore, the cooled mixture formed by the first flash evaporator 121, after passing through a portion of the second connecting pipe 1233, can be diverted to enter the first cooling pipe 115 and the liquid inlet pipe 112b of the chassis 112, respectively.

[0062] See also some of the possible implementation methods. Figure 1 As shown, the first flash evaporator 121 in this embodiment may include a primary flash tank 1211 and a secondary flash tank 1212. The primary flash tank 1211 can generate first steam and a first coolant. The first steam can enter a steam network. The secondary flash tank 1212 can continue to flash the first coolant to generate second steam and a second coolant. The second steam can enter a steam network. The second coolant can enter the first cooling pipe 115 and the inlet pipe 112b of the chassis 112 through the third branch pipe 1231 and the fourth branch pipe 1232, respectively, and circulate.

[0063] Since the heat generated by the first tail gas jacket 113 and the heat of the chassis 112 can be fully transferred to the furnace drum 111, two flash evaporations can be performed through the first-stage flash tank 1211 and the second-stage flash tank 1212 to extract high-grade steam more fully.

[0064] It should be noted that the first flash evaporator 121 may include, but is not limited to, a primary flash tank 1211 and a secondary flash tank 1212. The number of flash tanks included in the first flash evaporator 121 can be set according to requirements, and is not limited in this embodiment.

[0065] It is understandable that the internal condensate will be lost during the flashing process of the first flash evaporator 121. Therefore, a condensate delivery pipeline can be set at the second flash tank 1212 to replenish the second flash tank 1212 with condensate.

[0066] See also some of the possible implementation methods. Figure 1 As shown, the reduction furnace 110 in this embodiment may further include a second exhaust gas jacket 114. The second exhaust gas jacket 114 may be correspondingly provided with a second cooling pipe 116. The heat recovery system 100 of the reduction furnace 110 also includes a second circulation unit 130. The second circulation unit 130 may include a second flash evaporator 131. The second cooling pipe 116 is connected to the second flash evaporator 131. The second flash evaporator 131 can generate third steam and a third coolant. The third steam can enter the steam network, and the third coolant can flow back into the second cooling pipe 116 and circulate.

[0067] The first exhaust gas jacket 113 and the second exhaust gas jacket 114 can be connected. A circulating fluid can also be provided in the second cooling pipe 116. The circulating fluid in the second cooling pipe 116 can absorb the heat generated in the second exhaust gas jacket 114 to form a high-temperature circulating fluid. The high-temperature circulating fluid can be depressurized and flashed through the second flash evaporator 131 to form third steam and third coolant. The third steam, after entering the steam network, can be used to provide energy to other devices. The third coolant can flow back into the second cooling pipe 116 to absorb the heat generated in the second exhaust gas jacket 114 and circulate.

[0068] In this embodiment, the reduction furnace 110 can adopt an existing structure. The liquid outlet pipe 112a of the first cooling pipe 115 and the chassis 112 can be connected by a first parallel pipe 122 to connect with the liquid inlet 111a of the furnace cylinder 111. The liquid outlet of the first flash evaporator 121 can be connected by a second parallel pipe 123 to connect with the liquid inlet pipe 112b of the first cooling pipe 115 and the chassis 112, respectively. Therefore, this embodiment is an optimized design based on the existing mature reduction furnace 110 structure, which has a simple structure and high reliability.

[0069] In some examples, the second flash evaporator 131 may include, but is not limited to, a flash tank. The number of flash tanks included in the second flash evaporator 131 can be set according to requirements and is not limited in this embodiment.

[0070] It is understandable that the internal condensate will be lost during the flash evaporation process of the second flash evaporator 131. Therefore, a condensate delivery pipe can be set at the second flash evaporator 131 to replenish the condensate to the second flash evaporator 131.

[0071] In this embodiment, the first exhaust gas jacket 113 can be disposed on the side of the second exhaust gas jacket 114 close to the furnace cylinder 111, or the first exhaust gas jacket 113 can also be disposed on the side of the second exhaust gas jacket 114 away from the furnace cylinder 111. In this embodiment, no limitation is made.

[0072] In some examples, a first cooling pipe 115 may be fitted over the outside of a first exhaust gas jacket 113. The first cooling pipe 115 may be filled with circulating fluid to recover and reuse the heat generated within the first exhaust gas jacket 113. A second cooling pipe 116 may be fitted over the outside of a second exhaust gas jacket 114. The second cooling pipe 116 may also be filled with circulating fluid to recover and reuse the heat generated within the second exhaust gas jacket 114, thereby achieving energy recovery and reuse.

[0073] See also some of the possible implementation methods. Figure 1 As shown, the first circulation unit 120 in this embodiment may further include a first liquid circulation pump 124. The first liquid circulation pump 124 may be disposed between the secondary flash tank 1212 and the second parallel pipeline 123. The first liquid circulation pump 124 may be used to introduce the second coolant into the third branch pipe 1231 and the fourth branch pipe 1232 respectively.

[0074] The second circulation unit 130 may further include a second liquid circulation pump 132. The second liquid circulation pump 132 may be connected to the second flash evaporator 131. The second liquid circulation pump 132 may be used to introduce a third coolant into the second cooling pipe 116.

[0075] See also some of the possible implementation methods. Figure 1 As shown, in the first circulation unit 120 of this application embodiment, the furnace cylinder 111, chassis 112, first cooling pipe 115, primary flash tank 1211 and secondary flash tank 1212 can share a first liquid circulation pump 124.

[0076] In related technologies, the furnace cylinder 111, chassis 112, first cooling pipe 115, and flash tank are each equipped with a circulation pump to promote the flow of internal circulating liquid. In this embodiment, the furnace cylinder 111, chassis 112, first cooling pipe 115, primary flash tank 1211, and secondary flash tank 1212 are connected in series. Therefore, the flow of internal circulating liquid can be achieved by a single first liquid circulation pump 124, reducing the number of first liquid circulation pumps 124, saving equipment floor space, and thus helping to save the overall cost of the reduction furnace heat recovery system 100.

[0077] See also some of the possible implementation methods. Figure 1 As shown, the second tail gas jacket 114 can be located between the furnace tube 111 and the first tail gas jacket 113.

[0078] In this embodiment, the second exhaust gas jacket 114 can be closer to the furnace drum 111 than the first exhaust gas jacket 113. It is understood that the heat inside the second exhaust gas jacket 114 is higher than the heat inside the first exhaust gas jacket 113.

[0079] In some feasible implementations, the primary flash tank 1211 can be a steam flash tank with a steam pressure of 0.4 MPaG to 0.6 MPaG. The secondary flash tank 1212 can be a steam flash tank with a steam pressure of 0.2 MPaG to 0.3 MPaG. The second flash evaporator 131 can be a steam flash tank with a steam pressure of 0.8 MPaG to 1.1 MPaG.

[0080] Because the temperature inside the second exhaust gas jacket 114 is higher than the temperature inside the first exhaust gas jacket 113, the second flash evaporator 131, used to flash the heat inside the second exhaust gas jacket 114, can use a larger pressure value, namely 0.8 MPaG-1.1 MPaG. The second flash evaporator 131 can generate steam at 0.8 MPaG-1.1 MPaG.

[0081] The high-temperature mixture discharged from furnace 111 preferentially enters the primary flash tank 1211, and then enters the secondary flash tank 1212. The primary flash tank 1211 can generate steam with a strength of 0.4 MPaG-0.6 MPaG. The secondary flash tank 1212 can generate steam with a strength of 0.2 MPaG-0.3 MPaG.

[0082] Therefore, steam with a strength of 0.8 MPaG-1.1 MPaG, 0.4 MPaG-0.6 MPaG, and 0.2 MPaG-0.3 MPaG enters the steam pipeline network, thereby providing energy for other devices.

[0083] In some feasible implementations, in the reduction furnace heat recovery system 100 of this application embodiment, the temperature of the gas entering the first tail gas jacket 113 from the second tail gas jacket 114 is 210-230°C. The gas temperature at the end of the first tail gas jacket 113 away from the second tail gas jacket 114 is 150°C.

[0084] It is understandable that the greater the temperature difference between the gas entering the first exhaust gas jacket 113 and the gas leaving the first exhaust gas jacket 113, the higher the heat recovery efficiency. In the embodiments of this application, the two temperature differences can reach 60℃-80℃ to achieve high heat recovery and utilization, thereby helping to reduce energy consumption.

[0085] It should be noted that the numerical values ​​and ranges involved in this application are approximate values. Due to the influence of the manufacturing process, there may be a certain range of errors, which can be considered negligible by those skilled in the art.

[0086] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an indirect connection through an intermediate medium, or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0087] In the description of this application, it should be understood that the terms “center,” “length,” “width,” “thickness,” “top,” “bottom,” “upper,” “lower,” “left,” “right,” “front,” “rear,” “vertical,” “horizontal,” “inner,” “outer,” “axial,” and “circumferential,” etc., used to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the indicated position or component must have a specific orientation, or a specific structure and operation, and therefore should not be construed as a limitation of the present invention.

[0088] The devices or elements referred to in the embodiments of this application or implied herein must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the embodiments of this application. In the description of the embodiments of this application, "a plurality of" means two or more, unless otherwise precisely specified.

[0089] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in a sequence other than those illustrated or described herein.

[0090] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0091] The term "multiple" in this article refers to two or more. The term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Furthermore, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects; in formulas, the character " / " indicates a "division" relationship between the preceding and following related objects.

[0092] It is understood that the various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application.

[0093] It is understood that, in the embodiments of this application, the order of the above-mentioned process numbers does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

Claims

1. A heat recovery system for a reduction furnace, characterized in that, include: A reduction furnace, comprising a furnace cylinder, a chassis, and a first tail gas jacket, wherein a first cooling pipe is correspondingly provided on the first tail gas jacket; The first circulation unit includes a first flash evaporator, the first cooling pipe and the liquid outlet pipe of the chassis are both connected to the liquid inlet of the furnace cylinder, the liquid outlet of the furnace cylinder is connected to the first flash evaporator, and the first flash evaporator is connected to the first cooling pipe and the liquid inlet pipe of the chassis respectively. The first circulation unit further includes a first parallel pipeline, which includes a first branch pipe and a second branch pipe. The first cooling pipe is connected to the liquid inlet of the furnace cylinder through the first branch pipe, and the liquid outlet pipe of the chassis is connected to the liquid inlet of the furnace cylinder through the second branch pipe. The first circulation unit further includes a second parallel pipeline, which includes a third branch pipe and a fourth branch pipe. The first flash evaporator is connected to the first cooling pipe through the third branch pipe, and the first flash evaporator is connected to the liquid inlet pipe of the chassis through the fourth branch pipe. The first flash evaporator includes a primary flash tank and a secondary flash tank. The primary flash tank generates first steam and a first coolant. The first steam enters the steam pipeline network. The secondary flash tank continues to flash the first coolant to generate second steam and second coolant, and the second steam enters the steam pipeline network; The second coolant enters the first cooling pipe and the inlet pipe of the chassis through the third branch pipe and the fourth branch pipe respectively, and circulates. The primary flash tank is a 0.4MPaG-0.6MPaG steam flash tank; The secondary flash tank is a steam flash tank with a capacity of 0.2 MPaG-0.3 MPaG; The second flash evaporator is a steam flash tank with a power of 0.8 MPaG-1.1 MPaG.

2. The reduction furnace heat recovery system according to claim 1, characterized in that, The reduction furnace also includes a second tail gas jacket, and the second tail gas jacket is correspondingly provided with a second cooling pipe. The reduction furnace heat recovery system also includes a second circulation unit. The second circulation unit includes a second flash evaporator, and the second cooling pipe is connected to the second flash evaporator. The second flash evaporator generates a third steam and a third coolant. The third steam enters the steam network, and the third coolant flows back into the second cooling pipe and circulates.

3. The reduction furnace heat recovery system according to claim 2, characterized in that, The first circulation unit further includes a first liquid circulation pump, which is disposed between the secondary flash tank and the second parallel pipeline. The first liquid circulation pump introduces the second coolant into the third branch pipe and the fourth branch pipe respectively. The second circulation unit further includes a second liquid circulation pump, which is connected to the second flash evaporator, and the second liquid circulation pump introduces the third coolant into the second cooling pipe.

4. The reduction furnace heat recovery system according to claim 3, characterized in that, In the first circulation unit, the furnace drum, the chassis, the primary flash tank, and the secondary flash tank share a single first liquid circulation pump.

5. The reduction furnace heat recovery system according to claim 4, characterized in that, The second exhaust gas jacket is located between the furnace cylinder and the first exhaust gas jacket.

6. The reduction furnace heat recovery system according to claim 5, characterized in that, The temperature at which the gas in the second exhaust jacket enters the first exhaust jacket is 210-230℃; The gas temperature at the end of the first exhaust gas jacket furthest from the second exhaust gas jacket is 150°C.

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