High-temperature concentrated acid waste heat utilization system

Abstract

The utility model discloses a high-temperature concentrated acid waste heat utilization system which comprises a heat exchange mechanism, a water circulation mechanism and a pipeline, the heat exchange mechanism comprises a waste heat boiler, a first heat exchanger and a second heat exchanger; the water circulating mechanism comprises a deaerator and a circulating pump; a steam-water separator is further arranged at a water outlet of the waste heat boiler and communicated with the first heat exchanger, and the first heat exchanger and the second heat exchanger are communicated with the deaerator through pipelines. According to the utility model, the high-temperature concentrated acid is cooled in multiple stages, so that the recovery efficiency is remarkably improved, heat in the high-temperature concentrated acid is input into the production process again in the form of steam and high-temperature demineralized water to the greatest extent, the recycling of energy is realized, and the external energy demand and the operation cost are reduced; and meanwhile, the temperature of concentrated acid is effectively reduced, the risk of corrosion and damage of subsequent equipment is reduced, and the service life of accessories or equipment including a conventional fluorine lining valve is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of waste heat recovery and utilization in the process of acid production from smelting flue gas, and specifically to a high-temperature concentrated acid waste heat utilization system. Background Technology

[0002] In the process of producing acid from smelting flue gas, drying and absorption are carried out by primary drying and secondary absorption. In order to improve the utilization rate of waste heat, a low-temperature waste heat recovery system is used to recover heat. Specifically, the low-temperature waste heat recovery system and the intermediate absorption tower are integrated into one unit. The high-temperature concentrated acid after absorbing SO3 exchanges heat with demineralized water in the heat recovery boiler to produce low-pressure saturated steam, thereby maximizing the recovery of waste heat generated in the high-temperature concentrated acid production process.

[0003] The demineralized water is pumped from the waste heat power plant's feedwater pump through the pipeline network into the waste heat boiler drum, enters the boiler's heating surface, and after heating, returns to the waste heat boiler drum. The steam-water mixture returning to the drum undergoes steam-water separation in the boiler drum, with the separated water continuing to circulate. Saturated steam is drawn out of the boiler drum and enters the plant's low-pressure pipeline network to supply low-pressure steam users throughout the industrial park. The cooled high-temperature concentrated acid is partially used for process acid cooling and partially returned to the spray tower for flue gas scrubbing. The process acid is cooled by the low-temperature waste heat recovery system and then transported to the drying and final absorption pump tank. The specific process for cooling the high-temperature concentrated acid in the low-temperature heat recovery system is as follows:

[0004] Low-temperature waste heat recovery system pump tank → acid pump (approx. 1330 m³ / h, ~210℃) → heat recovery low-pressure boiler cooling - spray tower primary spray (approx. 1135 m³ / h, ~185℃) and heater inlet (approx. 194 m³ / h, ~185℃) → after heater cooling (approx. 194 m³ / h, ~153℃) → drying and final absorption pump tank.

[0005] As can be seen from the above high-temperature concentrated acid cooling process, after cooling by the low-temperature waste heat recovery system, the temperature of 99.3% of the high-temperature concentrated acid still reaches 153℃, indicating a certain potential for waste heat recovery and utilization. At the same time, high-temperature concentrated acid places high demands on pipeline equipment and facilities. Conventional fluoropolymer-lined valves have a shorter lifespan at high temperatures and need to be replaced regularly. After the high-temperature concentrated acid enters the dry suction pump tank, it increases the acid temperature of the dry suction tank, increasing the overall operating load. In particular, the inlet temperature of this device is close to the upper limit of the heat exchange tube temperature of 110℃, which will also aggravate the corrosion of the tube bundle. Therefore, reducing the temperature of the concentrated acid to below 110℃ before recovery can effectively extend the service life of related equipment. Thus, the existing low-temperature recovery system needs to be improved. Summary of the Invention

[0006] In view of the shortcomings of the above-mentioned high-temperature concentrated acid still having a lot of residual heat after passing through the low-temperature waste heat recovery system, which not only easily leads to resource waste but also easily damages related equipment, this utility model provides a high-temperature concentrated acid waste heat utilization system that can effectively utilize the heat of high-temperature concentrated acid and extend the service life of related processing equipment.

[0007] To achieve the above objectives, the technical solution of this utility model is as follows:

[0008] A high-temperature concentrated acid waste heat utilization system includes a heat exchange mechanism, a water circulation mechanism, and pipelines. The heat exchange mechanism includes a waste heat boiler, a first heat exchanger, and a second heat exchanger, with the outlet and inlet connected sequentially via pipelines. The water circulation mechanism includes a deaerator and a circulation pump, with the outlet and inlet connected sequentially via pipelines. The outlet of the circulation pump supplies water to the waste heat boiler and the first heat exchanger via pipelines. A steam-water separator is also provided at the outlet of the waste heat boiler. The condensate outlet of the steam-water separator is connected to the pipeline at the inlet of the first heat exchanger, and the outlets of the first and second heat exchangers are respectively connected to the pipeline at the inlet of the deaerator via pipelines.

[0009] Furthermore, the main body of the first heat exchanger is a heat exchange cylinder A, with an inlet and an outlet on its two sides, respectively. It also contains a hot water exchange pipe, with the inlet connected to the outlet of the waste heat boiler via a pipe, and the outlet connected to the inlet of the second heat exchanger. The hot water exchange pipe is a spiral tube, with its inlet and outlet extending outwards from the heat exchange cylinder A and connected to the circulating pump and deaerator via pipes. The spiral hot water exchange pipe design in heat exchange cylinder A effectively increases the heat exchange area and efficiency, allowing the high-temperature concentrated acid from the waste heat boiler to more fully exchange heat with the water in the hot water exchange pipe. The spiral tube design not only optimizes the fluid flow path and reduces thermal resistance but also enhances turbulence and improves the heat transfer rate.

[0010] Furthermore, the second heat exchanger body is a heat exchange cylinder B, with an inlet and an outlet on its two sides, respectively. Inside, there is a double-layered nested heat exchange tube assembly. The inlet is connected to the outlet of the first heat exchanger via a pipe. The two ends of the heat exchange tube assembly are an inlet pipe and an outlet pipe, respectively, connected to the outer wall of the heat exchange cylinder B. The outlet pipe is connected to the deaerator via a pipe. The plant's ambient temperature demineralized water pipeline is connected to the inlet pipe of the heat exchange tube assembly, and ambient temperature demineralized water is introduced for heat exchange during use. The double-layered nested structure of the heat exchange tube assembly increases the heat exchange area and optimizes the fluid flow path, allowing for more thorough heat exchange between the high-temperature concentrated acid from the first heat exchanger and the ambient temperature demineralized water. This enables rapid cooling of the high-temperature concentrated acid, improving heat transfer efficiency and allowing the plant to flexibly adjust heat distribution according to actual needs, ensuring optimal energy utilization under different operating conditions.

[0011] Furthermore, the heat exchange tube assembly includes two spiral heat exchange tubes of the same shape but different sizes, wherein the smaller spiral heat exchange tube is nested inside the larger spiral heat exchange tube, and a connecting block is provided between the two spiral heat exchange tubes to fix them together as a whole. The inlet and outlet of the two spiral heat exchange tubes are connected by a tee, and the other end of the tee passes through the heat exchange cylinder B and connects to the pipeline. During operation, the ambient temperature demineralized water is piped into the inlet tee. The tee distributes the water to two spiral heat exchange pipes. After heat exchange, the water collects at the outlet tee and is then connected to a pipeline to the deaerator. The two spiral heat exchange pipes significantly increase the heat exchange area, allowing for more thorough heat exchange between the ambient temperature demineralized water and the high-temperature concentrated acid during flow. This enables a faster and more effective reduction of the concentrated acid temperature from 210℃ to 94℃, resulting in high waste heat recovery efficiency. The tee design rationally distributes and collects water flow, ensuring uniform distribution and efficient heat transfer. This simplifies the system structure, facilitating maintenance and repair. Furthermore, the connecting block securely connects the two spiral water pipes into a single unit, enhancing structural stability, preventing deformation or displacement under high temperature and pressure conditions, and extending the equipment's service life.

[0012] Furthermore, a mixer is connected to the pipe before the deaerator inlet; the mixer's outlet is connected to the deaerator via a pipe, and its inlet is connected to the high-temperature demineralized water outlets of the first and second heat exchangers via pipes. The high-temperature demineralized water flowing out of the first and second heat exchangers is mixed evenly by the mixer before being fed into the deaerator for deoxygenation. The mixer ensures that high-temperature demineralized water at different temperatures is evenly mixed before entering the deaerator, avoiding temperature fluctuations and local overheating, improving water temperature stability, optimizing deoxygenation effect, reducing the impact on the internal structure and operating performance of the deaerator, and extending the equipment's service life.

[0013] Furthermore, the main body of the deaerator is a mixing pipe, with an inlet and an outlet at each end. Several baffles are arranged alternately inside the pipe. There are two inlets, each connected to the outlet of the first heat exchanger and the outlet of the second heat exchanger via pipes. The outlets are connected to the inlet of the deaerator via pipes. The high-temperature demineralized water discharged from the first and second heat exchangers enters the mixing pipe and is uniformly mixed by the baffles before deaeration, effectively ensuring uniform water temperature. The alternately arranged baffles inside the mixing pipe increase the complexity of the water flow path, prolonging the residence time of the water within the pipe and promoting more thorough heat exchange and mixing, thereby improving the stability and uniformity of the water temperature entering the deaerator.

[0014] How to use:

[0015] During system installation, the inlet of the waste heat boiler is connected to the plant's high-temperature hot acid pipeline; the outlet of the second heat exchanger is connected to the inlet of the plant's process acid-cooling equipment; the outlet of the steam-water separator is connected to the plant's gas supply pipeline; and the inlet of the second heat exchanger is connected to the plant's ambient temperature demineralized water pipeline. When the system is in operation, the circulating pump is turned on, pumping the high-temperature demineralized water from the deaerator into the waste heat boiler and the first heat exchanger. The high-temperature concentrated acid first enters the waste heat boiler for the first heat exchange, heating the high-temperature demineralized water into high-temperature steam. This high-temperature steam enters the steam-water separator, and the separated steam enters the plant's gas supply pipeline. The separated condensate mixes with the high-temperature demineralized water entering the first heat exchanger and then enters the first heat exchanger together. At this point, the temperature of the high-temperature concentrated acid discharged from the waste heat boiler is... The temperature drops from 210℃ to 153℃. In the first heat exchanger, the high-temperature concentrated acid exchanges heat with the mixture of high-temperature demineralized water and condensate in the first heat exchanger, allowing the mixed demineralized water in the first heat exchanger to maintain a high temperature before being discharged from the first heat exchanger. At this time, the temperature of the high-temperature concentrated acid discharged from the first heat exchanger drops from 153℃ to 143℃. In the second heat exchanger, the room-temperature demineralized water from the factory exchanges heat with the high-temperature concentrated acid after the second cooling. After the heat exchange, the room-temperature demineralized water forms high-temperature demineralized water before being discharged from the second heat exchanger. At this time, the temperature of the high-temperature concentrated acid discharged from the second heat exchanger drops from 143℃ to 94℃. The high-temperature demineralized water discharged from the first and second heat exchangers is mixed in the pipeline and then fed into the deaerator. After being deoxygenated by the deaerator, it enters the circulating pump and is then transported by the circulating pump. The waste heat utilization system forms a cycle.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0017] 1. This utility model significantly improves the waste recovery efficiency by optimizing the heat exchange process and cooling high-temperature concentrated acid in multiple stages. It also maximizes the reuse of heat from the high-temperature concentrated acid in the form of steam and high-temperature demineralized water in the production process, realizing the recycling of energy and reducing external energy demand and operating costs. At the same time, the system effectively reduces the temperature of concentrated acid from 210℃ to 94℃, which not only reduces the load on downstream equipment and the risk of equipment corrosion and damage, but also extends the service life of accessories or equipment, including conventional fluoropolymer-lined valves.

[0018] 2. The spiral hot water pipe design in heat exchanger tube A of this utility model effectively increases the heat exchange area and heat exchange efficiency, allowing the high-temperature concentrated acid from the waste heat boiler to exchange heat more fully with the water in the hot water pipe, thus improving the heat transfer rate. The double-layer nested structure of the heat exchanger tube group increases the heat exchange area, allowing the high-temperature concentrated acid from the first heat exchanger to exchange heat more fully with the room-temperature demineralized water, which can quickly cool down the high-temperature concentrated acid and improve the heat transfer efficiency. At the same time, the factory can flexibly adjust the heat distribution according to actual needs to ensure optimal energy utilization under different operating conditions.

[0019] 3. This new mixer ensures that high-temperature demineralized water at different temperatures is uniformly mixed before entering the deaerator, avoiding temperature fluctuations and localized overheating, improving water temperature stability, optimizing deaeration, reducing the impact on the internal structure and operating performance of the deaerator, and extending the equipment's service life. The staggered baffles inside the mixing pipe increase the complexity of the water flow path, prolong the water's residence time in the pipe, and promote more thorough heat exchange and mixing, thereby improving the stability and uniformity of the water temperature entering the deaerator. Attached Figure Description

[0020] Figure 1 This is an overall layout diagram of a high-temperature concentrated acid waste heat utilization system according to this utility model.

[0021] Figure 2 This is a schematic diagram of the internal structure of the first heat exchanger in a high-temperature concentrated acid waste heat utilization system of this utility model.

[0022] Figure 3 This is a schematic diagram of the internal structure of the second heat exchanger in a high-temperature concentrated acid waste heat utilization system according to this utility model.

[0023] Figure 4 This is a schematic diagram showing the installation relationship of two spiral hot water exchange pipes in a high-temperature concentrated acid waste heat utilization system according to this utility model.

[0024] Figure 5 This is a schematic diagram of the internal structure of a mixer in a high-temperature concentrated acid waste heat utilization system according to this utility model.

[0025] Attached image labels:

[0026] Pipeline—1, Waste heat boiler—2, First heat exchanger—3, Heat exchange cylinder A—31, Hot water pipe—32, Second heat exchanger—4, Heat exchange cylinder B—41, Heat exchange tube assembly—42, Spiral hot water pipe—421, Connecting block—422, Tee—423, Deaerator—5, Circulating pump—6, Steam-water separator—7, Mixer—8, Baffle—81. Detailed Implementation

[0027] Except for those modifications, all other instruments and equipment used in the embodiments are commercially available products of the prior art. The present invention will be further described below with reference to the accompanying drawings.

[0028] Example 1: Reference Figure 1 The bold arrows indicate the flow path of the high-temperature concentrated acid, while the thin arrows indicate the circulation path of the demineralized water.

[0029] A high-temperature concentrated acid waste heat utilization system includes a heat exchange mechanism, a water circulation mechanism, and a pipeline 1. The heat exchange mechanism includes a waste heat boiler 2, a first heat exchanger 3, and a second heat exchanger 4, whose outlet and inlet are connected in sequence via the pipeline 1. The water circulation mechanism includes a deaerator 5 and a circulation pump 6, whose outlet and inlet are connected in sequence via the pipeline 1. The outlet of the circulation pump 6 delivers water to the waste heat boiler 2 and the first heat exchanger 3 via the pipeline 1. A steam-water separator 7 is also provided at the outlet of the waste heat boiler 2. The condensate outlet of the steam-water separator 7 is also connected to the pipeline 1 at the inlet of the first heat exchanger 3. The outlets of the first heat exchanger 3 and the second heat exchanger 4 are respectively connected to the pipeline 1 at the inlet of the deaerator 5 via the pipeline 1.

[0030] During system installation, the inlet of waste heat boiler 2 is connected to the high-temperature hot acid pipeline 1 of the factory; the outlet of the second heat exchanger 4 is connected to the liquid inlet of the factory's process acid-cooling equipment; the outlet of the steam-water separator 7 is connected to the factory's gas supply pipeline; and the inlet of the second heat exchanger 4 is connected to the factory's ambient temperature demineralized water pipeline 1 via pipeline 1. When the system is in use, the circulating pump 6 is turned on, pumping the high-temperature demineralized water after deoxygenation by the deaerator 5 into waste heat boiler 2 and the first heat exchanger 3 respectively. The high-temperature concentrated acid first enters waste heat boiler 2 for the first heat exchange, heating the high-temperature demineralized water entering waste heat boiler 2 to form high-temperature steam. The high-temperature steam enters the steam-water separator 7, and the separated steam enters the factory's gas supply pipeline. The separated condensate mixes with the high-temperature demineralized water entering the first heat exchanger 3 and then enters the first heat exchanger 3 together. At this time, the high-temperature concentrated acid discharged from waste heat boiler 2 is at a temperature... The temperature drops from 210℃ to 153℃. In the first heat exchanger 3, the high-temperature concentrated acid exchanges heat with the mixture of high-temperature demineralized water and condensate in the first heat exchanger 3, so that the mixed demineralized water in the first heat exchanger 3 can maintain a high temperature before being discharged from the first heat exchanger 3. At this time, the temperature of the high-temperature concentrated acid discharged from the first heat exchanger 3 drops from 153℃ to 143℃. In the second heat exchanger 4, the room-temperature demineralized water from the factory exchanges heat with the high-temperature concentrated acid after the second cooling. After the heat exchange, the room-temperature demineralized water forms high-temperature demineralized water before being discharged from the second heat exchanger 4. At this time, the temperature of the high-temperature concentrated acid discharged from the second heat exchanger 4 drops from 143℃ to 94℃. The high-temperature demineralized water discharged from the first heat exchanger 3 and the second heat exchanger 4 are mixed in the pipeline 1 and then fed into the deaerator 5. After being deoxygenated by the deaerator 5, it enters the circulation pump 6 and is then transported by the circulation pump 6. The waste heat utilization system forms a cycle.

[0031] Example 2: The difference from Example 1 is that the main body of the first heat exchanger 3 is a heat exchange cylinder A31, with an inlet and an outlet on either side. A hot water exchange pipe 32 is also installed inside. The inlet is connected to the outlet of the waste heat boiler 2 via pipe 1, and the outlet is connected to the inlet of the second heat exchanger 4. The hot water exchange pipe 32 is a spiral tube, with its inlet and outlet extending outwards from the heat exchange cylinder A31 and connected to the circulating pump 6 and deaerator 5 via pipe 1. The spiral hot water exchange pipe 421 design in the heat exchange cylinder A31 effectively increases the heat exchange area and efficiency, allowing the high-temperature concentrated acid from the waste heat boiler 2 to more fully exchange heat with the water in the hot water exchange pipe 32. The spiral tube design not only optimizes the fluid flow path and reduces thermal resistance but also enhances turbulence and improves the heat transfer rate.

[0032] A mixer 8 is also connected to the pipe 1 before the inlet of the deaerator 5. The outlet of the mixer 8 is connected to the deaerator 5 through the pipe 1, and the inlet is connected to the high-temperature demineralized water outlets of the first heat exchanger 3 and the second heat exchanger 4 through the pipe 1. The high-temperature demineralized water flowing out of the first heat exchanger 3 and the second heat exchanger 4 is mixed evenly by the mixer 8 before being fed into the deaerator 5 for deoxygenation. The mixer 8 ensures that the high-temperature demineralized water of different temperatures is evenly mixed before entering the deaerator 5, avoiding temperature fluctuations and local overheating problems, improving water temperature stability, optimizing the deoxygenation effect, reducing the impact on the internal structure and operating performance of the deaerator 5, and extending the service life of the equipment.

[0033] Example 3: Unlike Example 2, the second heat exchanger 4 is primarily a heat exchange cylinder B41. The heat exchange cylinder B41 has an inlet and an outlet on its two sides, respectively. Inside, it is equipped with a double-nested heat exchange tube assembly 42. The inlet is connected to the outlet of the first heat exchanger 3 via a pipe 1. The two ends of the heat exchange tube assembly 42 are an inlet pipe and an outlet pipe, respectively, connecting to the outer wall of the heat exchange cylinder B41. The outlet pipe is connected to the deaerator 5 via pipe 1. The factory's ambient temperature demineralized water pipe 1 is connected to the inlet pipe of the heat exchange tube assembly 42, allowing ambient temperature demineralized water to be introduced for heat exchange during use. The double-nested structure of the heat exchange tube assembly 42 increases the heat exchange area and optimizes the fluid flow path, enabling more thorough heat exchange between the high-temperature concentrated acid from the first heat exchanger 3 and the ambient temperature demineralized water. This allows for rapid cooling of the high-temperature concentrated acid, improving heat transfer efficiency and allowing the factory to flexibly adjust heat distribution according to actual needs, ensuring optimal energy utilization under different operating conditions.

[0034] The main body of the deaerator 5 is a mixing pipe, with an inlet and an outlet at each end. Several baffles 81 are arranged alternately inside the pipe. There are two inlets, each connected to the outlet of the first heat exchanger 3 and the outlet of the second heat exchanger 4 via pipe 1. The outlets are connected to the inlet of the deaerator 5 via pipe 1. The high-temperature demineralized water discharged from the first heat exchanger 3 and the second heat exchanger 4 enters the mixing pipe and is uniformly mixed by the baffles 81 before deoxygenation, effectively ensuring uniform water temperature. The alternating baffles 81 inside the mixing pipe increase the complexity of the water flow path, prolong the residence time of the water in the pipe, and promote more thorough heat exchange and mixing, thereby improving the stability and uniformity of the water temperature entering the deaerator 5.

[0035] Example 4: The difference from Example 3 is that the heat exchange tube assembly 42 includes two spiral heat exchange tubes 421 of the same shape but different sizes. The smaller spiral heat exchange tube 421 is nested inside the larger spiral heat exchange tube 421. A connecting block 422 is provided between the two spiral heat exchange tubes 421, and they are fixedly connected into a whole by the connecting block 422. The inlet and outlet of the two spiral heat exchange tubes 421 are connected by a tee 423, and the other end of the tee 423 passes through the heat exchange cylinder B41 and connects to the pipe 1. During operation, the ambient temperature demineralized water enters through pipe 1 via the inlet tee 423. The tee 423 distributes the water to two spiral heat exchange pipes 421. After heat exchange, the water collects at the outlet tee 423 and is then connected to pipe 1 via the tee 423 before being transported to the deaerator 5. The two spiral heat exchange pipes 421 significantly increase the heat exchange area, allowing for more thorough heat exchange between the ambient temperature demineralized water and the high-temperature concentrated acid during flow. This enables a faster and more effective reduction of the concentrated acid temperature from 210℃ to 94℃, resulting in high waste heat recovery efficiency. The tee 423's rational design for distributing and collecting water flow ensures uniform distribution and efficient heat transfer, simplifying the system structure and facilitating maintenance and repair. Furthermore, the connecting block 422 securely connects the two spiral water pipes into a single unit, enhancing structural stability, preventing deformation or displacement under high temperature and pressure conditions, and extending the equipment's service life.

[0036] Numerous specific details are set forth in this specification. However, it will be understood that embodiments of this invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model, and they should all be covered within the scope of the claims and specification of this utility model.

Claims

1. A high-temperature concentrated acid waste heat utilization system, characterized in that: It includes a heat exchange mechanism, a water circulation mechanism, and a pipeline (1); the heat exchange mechanism includes a waste heat boiler (2), a first heat exchanger (3), and a second heat exchanger (4) connected sequentially to the outlet and the inlet via the pipeline (1); the water circulation mechanism includes a deaerator (5) and a circulation pump (6) connected sequentially to the outlet and the inlet via the pipeline (1), wherein the outlet of the circulation pump (6) delivers water to the waste heat boiler (2) and the first heat exchanger (3) respectively via the pipeline (1); a steam-water separator (7) is also provided at the outlet of the waste heat boiler (2), and the condensate outlet of the steam-water separator (7) is also connected to the pipeline (1) at the inlet of the first heat exchanger (3), and the outlets of the first heat exchanger (3) and the second heat exchanger (4) are respectively connected to the pipeline (1) at the inlet of the deaerator (5) via the pipeline (1).

2. The high-temperature concentrated acid waste heat utilization system as described in claim 1, characterized in that: The main body of the first heat exchanger (3) is a heat exchange cylinder A (31). The two sides of the heat exchange cylinder A (31) are the inlet and the outlet, respectively. The heat exchange water pipe (32) is also provided inside. The inlet is connected to the outlet of the waste heat boiler (2) through the pipe (1), and the outlet is connected to the inlet of the second heat exchanger (4). The heat exchange water pipe (32) is a spiral pipe. The inlet and outlet of the pipe extend outward from the heat exchange cylinder A (31) and are connected to the circulating pump (6) and the deaerator (5) through the pipe (1).

3. A high-temperature concentrated acid waste heat utilization system as described in any one of claims 1 or 2, characterized in that: The second heat exchanger (4) is mainly a heat exchange cylinder B (41). The two sides of the heat exchange cylinder B (41) are the inlet and the outlet, respectively. The heat exchange tube group (42) with a double-layer nested structure is also provided inside. The liquid inlet is connected to the liquid outlet of the first heat exchanger (3) through a pipe (1). The two ends of the heat exchange tube group (42) are the water inlet pipe and the water outlet pipe that are connected to the outer wall of the heat exchange cylinder B (41), respectively. The water outlet pipe is connected to the deaerator (5) through the pipe (1).

4. The high-temperature concentrated acid waste heat utilization system as described in claim 3, characterized in that: The heat exchange tube assembly (42) includes two spiral heat exchange tubes (421) of the same shape but different sizes. The smaller spiral heat exchange tube (421) is nested inside the larger spiral heat exchange tube (421). A connecting block (422) is provided between the two spiral heat exchange tubes (421). The two spiral heat exchange tubes (421) are fixedly connected into a whole through the connecting block (422). The inlet and outlet of the two spiral heat exchange tubes (421) are connected by a tee (423). The other end of the tee (423) passes through the heat exchange cylinder B (41) and connects to the pipe (1).

5. The high-temperature concentrated acid waste heat utilization system as described in claim 1, characterized in that: The pipe (1) before the inlet of the deaerator (5) is also connected to a mixer (8); the outlet of the mixer (8) is connected to the deaerator (5) through the pipe (1), and the inlet is connected to the high-temperature demineralized water outlet of the first heat exchanger (3) and the second heat exchanger (4) through the pipe (1).

6. The high-temperature concentrated acid waste heat utilization system as described in claim 5, characterized in that: The main body of the deaerator (5) is a mixing pipe, with an inlet and an outlet at both ends. Several baffles (81) are arranged inside. There are two inlets, which are connected to the outlet of the first heat exchanger (3) and the outlet of the second heat exchanger (4) through pipes (1). The outlets are connected to the inlet of the deaerator (5) through pipes (1).

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