An environmentally friendly continuous flow waste heat recovery device and method for sulfuric acid

Abstract

This invention discloses an environmentally friendly continuous flow waste heat recovery device and method for sulfuric acid, belonging to the technical field of waste heat recovery devices. It includes a flexible inner shell with a supporting frame inside. The flexible inner shell is connected to a pressure-bearing outer shell via a first connecting pipe at its top. Heat-conducting oil is filled between a protective layer inside the pressure-bearing outer shell and the flexible inner shell. Static gas is placed between the protective layer and the inner wall of the pressure-bearing outer shell. A first pressure sensor and a second pressure sensor on the inner and outer sides of the flexible inner shell respectively detect the pressure applied by the sulfuric acid reaction solution and the heat-conducting oil. This invention, by incorporating a flexible inner shell, a pressure-bearing outer shell, a first oil pump, a second oil pump, a first pressure sensor, and a second pressure sensor, achieves continuous and stable recovery of waste heat during the sulfuric acid reaction process, improving overall energy utilization efficiency, enhancing equipment reliability and service life, optimizing heat transfer efficiency, and reducing the need for manual intervention.

Description

Technical Field

[0001] This invention relates to the field of waste heat recovery equipment technology, specifically to an environmentally friendly continuous flow waste heat recovery device and method for sulfuric acid. Background Technology

[0002] Sulfuric acid, as an important basic chemical raw material, is widely used in fertilizer, metallurgy, petroleum refining and titanium dioxide production. In the process of sulfuric acid production and application, especially in the process links such as waste acid concentration, sulfonation reaction and alkylation reaction, a large amount of high temperature concentrated sulfuric acid reaction solution is generated, with the temperature reaching above 100°C. It contains abundant waste heat resources. If this waste heat is effectively recovered and utilized, it will be of great significance for reducing enterprise energy consumption, reducing greenhouse gas emissions and realizing comprehensive resource utilization.

[0003] Currently, industrial waste heat recovery for sulfuric acid media mainly uses metal heat exchange equipment. However, traditional metal or graphite heat exchangers are prone to corrosion damage to their heat exchange walls during long-term operation, leading to increased risk of equipment leakage and shortened service life. Moreover, the sulfuric acid reaction process is often accompanied by pressure fluctuations. Especially in continuous flow reactions, changes in the flow rate, temperature, and reaction intensity of the sulfuric acid solution can cause unstable system pressure. Traditional rigid heat exchange devices cannot adapt to such pressure changes, and large pressure differences can easily occur on the inside and outside of the heat exchange element. This causes the heat exchange wall to be subjected to alternating stress, accelerating fatigue damage and, in severe cases, even rupture accidents, resulting in sulfuric acid leakage, safety accidents, and environmental pollution.

[0004] Patent CN120650693B discloses a waste heat recovery device for a low-temperature recovery section in a sulfuric acid chemical industry. The above patent achieves an improvement in energy recovery and utilization rate.

[0005] The aforementioned patent includes a sulfuric acid inlet pipe for conveying concentrated sulfuric acid from the evaporation feedwater heater, and also includes a phase change heat recovery device. A sulfuric acid inlet is provided on one side for concentrated sulfuric acid to enter, and a sulfuric acid outlet is provided on the other side for the concentrated sulfuric acid to be discharged after heat exchange. It makes full use of the waste heat of concentrated sulfuric acid, but there is still room for optimization in adapting to pressure fluctuations during the sulfuric acid reaction process.

[0006] Therefore, this application proposes an environmentally friendly continuous flow waste heat recovery device and method for sulfuric acid that can adapt to pressure fluctuations during the sulfuric acid reaction process and has good corrosion resistance and high-efficiency heat insulation performance. Summary of the Invention

[0007] The purpose of this invention is to provide an environmentally friendly sulfuric acid continuous flow waste heat recovery device and recovery method to solve the technical problems mentioned in the background art, such as the inability of traditional rigid heat exchange devices to adapt to the pressure changes caused by sulfuric acid reaction, the large pressure difference between the inner and outer sides of the heat exchange element, the alternating stress on the heat exchange wall surface, accelerated fatigue damage, and even rupture accidents in severe cases, resulting in sulfuric acid leakage, safety accidents and environmental pollution.

[0008] To achieve the above objectives, the present invention provides the following technical solution: an environmentally friendly sulfuric acid continuous flow waste heat recovery device, comprising a flexible inner shell and a pressure-bearing outer shell. A supporting frame is provided inside the flexible inner shell, which is filled with a sulfuric acid reaction solution. The flexible inner shell is connected to the pressure-bearing outer shell via a first connecting pipe at its top. Heat-conducting oil is disposed between a protective layer inside the pressure-bearing outer shell and the flexible inner shell. Static gas is disposed between the protective layer and the inner wall of the pressure-bearing outer shell. A first pressure sensor and a second pressure sensor on the inner and outer sides of the flexible inner shell respectively detect the pressure applied by the sulfuric acid reaction solution and the heat-conducting oil. A first oil pump at the top of the pressure-bearing outer shell delivers low-temperature heat-conducting oil through an inlet pipe, and a second oil pump at the bottom of the pressure-bearing outer shell outputs high-temperature heat-conducting oil through an outlet pipe.

[0009] Preferably, the inner wall side of the flexible inner shell is in contact with the outer wall side of the supporting frame, and the supporting frames are fixed together by fixing rings. A first pressure sensor is provided on the inner wall side of the flexible inner shell, and the first pressure sensor detects the pressure exerted by the sulfuric acid reaction solution on the inner wall of the flexible inner shell.

[0010] Preferably, a first connecting pipe is provided at the top of the outer wall of the flexible inner shell, a rubber ring is provided on the side of the outer wall of the first connecting pipe, the thread on the outer wall of the first connecting pipe meshes with the thread groove on the inner wall of the second connecting pipe, and the second connecting pipe is provided at the top of the outer wall of the pressure-bearing outer shell.

[0011] Preferably, the pressure-bearing outer shell is provided with a protective layer inside, and a heat-conducting cavity is formed between the protective layer and the outer wall of the flexible inner shell. The heat-conducting cavity is filled with heat-conducting oil, and a second pressure sensor is provided on the side of the outer wall of the flexible inner shell. The second pressure sensor detects the pressure exerted by the heat-conducting oil on the outer wall of the flexible inner shell.

[0012] Preferably, an oil inlet pipe is provided at the top of the outer wall of the pressure-bearing shell, the bottom end of the oil inlet pipe is connected to the heat conduction cavity, the top end of the oil inlet pipe is connected to the first oil pump, an oil outlet pipe is provided at the bottom of the outer wall of the pressure-bearing shell, the top end of the oil outlet pipe is connected to the heat conduction cavity, the bottom end of the oil outlet pipe is connected to the second oil pump, and oil delivery pipes are provided on the outside of both the first and second oil pumps. The first and second oil pumps are connected to an external heat exchanger through the oil delivery pipes.

[0013] Preferably, the protective layer inside the pressure-bearing shell is made of a low thermal conductivity material, and a heat insulation cavity is formed between the protective layer and the inner wall of the pressure-bearing shell, which is filled with static gas.

[0014] Preferably, an air inlet pipe is provided at the top of the outer wall of the pressure-bearing shell, the top of the air inlet pipe is connected to a first solenoid valve, and the bottom of the air inlet pipe is connected to a heat insulation cavity. An air outlet pipe is provided at the bottom of the outer wall of the pressure-bearing shell, the top of the air outlet pipe is connected to the heat insulation cavity, and the bottom of the air outlet pipe is connected to a second solenoid valve. An air pump is connected to the air inlet pipe through the first solenoid valve and to the air outlet pipe through the second solenoid valve.

[0015] Preferably, the first solenoid valve, the second solenoid valve, and the air pump are all connected to the control console via external connecting cables. The control console has a built-in Bluetooth communication module, which is connected to the first pressure sensor and the second pressure sensor via the Bluetooth communication module. The control console controls the first oil pump and the second oil pump via connecting cables.

[0016] Preferably, the waste heat recovery method includes the following steps:

[0017] S1. Connect the first connecting pipe of the flexible inner shell to the second connecting pipe of the pressure-bearing outer shell by thread and seal it with a rubber ring. Then inject heat transfer oil into the heat transfer cavity through the oil inlet pipe until the heat transfer oil completely fills the heat transfer cavity between the flexible inner shell and the protective layer.

[0018] S2. The control console starts the air pump and opens the first solenoid valve to fill the insulation cavity with static gas with low thermal conductivity through the air inlet pipe. The control console can also evacuate the insulation cavity through the second solenoid valve and the air outlet pipe to reduce the thermal conductivity of the gas in the insulation cavity and reduce the heat loss from the heat-conducting cavity to the pressure-bearing shell through the protective layer.

[0019] S3. The pressure on the inner and outer sides of the flexible inner shell is dynamically adjusted based on the pressure data detected by the first and second pressure sensors to balance the pressure on the inner and outer sides of the flexible inner shell. At the same time, the heat of the sulfuric acid reaction solution is transferred to the heat transfer oil in the heat transfer cavity through the flexible inner shell. After absorbing heat, the temperature of the heat transfer oil rises. The second oil pump extracts the high-temperature heat transfer oil through the oil outlet pipe and delivers it to the external heat exchanger for heat exchange. The low-temperature heat transfer oil that releases heat is transported back to the heat transfer cavity through the first oil pump and the oil inlet pipe, forming a continuous circulation heat exchange.

[0020] Preferably, the waste heat recovery method further includes the following steps:

[0021] S31. When adjusting the pressure on the inner and outer sides of the flexible inner shell, the control console is connected to the first pressure sensor and the second pressure sensor to detect the pressure P1 applied to the inner wall of the flexible inner shell by the sulfuric acid reaction solution and the pressure P2 applied to the outer wall of the flexible inner shell by the heat transfer oil in real time. The control console receives the P1 and P2 data and controls the start, stop and flow rate of the first oil pump and the second oil pump through the connecting line, and adjusts the input and output of the heat transfer oil so that P2 always dynamically follows P1 and keeps the absolute value of the pressure difference between P1 and P2 less than the preset threshold.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] 1. This invention, by incorporating a supporting frame, a flexible inner shell, a protective layer, and a pressure-bearing outer shell, achieves stable load-bearing and preliminary thermal isolation of the sulfuric acid reaction solution during continuous flow. It solves the problem of sulfuric acid reaction vessels being easily damaged due to direct exposure to high-temperature, high-pressure corrosive media, and the significant heat loss through the vessel walls. The supporting frame provides structural support to the flexible inner shell, enabling it to withstand the internal solution pressure while maintaining flexibility. The flexible inner shell is made of high-temperature and concentrated sulfuric acid-resistant materials, ensuring long-term stable operation. The heat insulation cavity formed between the protective layer and the pressure-bearing outer shell lays the foundation for subsequent efficient heat insulation. This invention constructs a safe and reliable main structure for the sulfuric acid reaction vessel, ensuring mechanical strength, creating basic conditions for waste heat recovery, extending equipment lifespan, reducing maintenance costs, and providing structural guarantees for subsequent heat transfer and recovery.

[0024] 2. This invention, by incorporating a heat-conducting cavity, heat-conducting oil, a first oil pump, a second oil pump, and a flexible inner shell, achieves continuous and efficient recovery and utilization of heat released from the sulfuric acid reaction. It solves the problem that the heat-conducting cavity can only passively insulate and cannot actively recover waste heat. The heat-conducting cavity is located between the flexible inner shell and the protective layer. The heat-conducting oil, as the heat transfer medium, directly contacts the outer wall of the flexible inner shell, rapidly absorbing the heat released from the sulfuric acid reaction. The first oil pump continuously inputs low-temperature heat-conducting oil, while the second oil pump simultaneously outputs high-temperature heat-conducting oil, forming a closed-loop circuit. The high-temperature heat-conducting oil is transported to an external heat exchanger for heat exchange, releasing heat before returning to the heat-conducting cavity, thus achieving continuous recovery of waste heat. This efficiently converts potentially wasted reaction heat into reusable energy, improving overall energy utilization efficiency. The circulating heat exchange ensures the continuity and stability of heat transfer, avoiding the risk of equipment overheating due to heat accumulation, and providing a mature heat exchange solution for industrial applications.

[0025] 3. This invention, by incorporating a first pressure sensor, a second pressure sensor, a control console, heat transfer oil, a first oil pump, and a second oil pump, achieves dynamic balance control of the pressure on the inner and outer sides of the flexible inner shell. This solves the problem of the flexible inner shell bearing additional stress and being prone to mechanical damage due to pressure fluctuations in the sulfuric acid reaction solution during heat transfer oil circulation. The first pressure sensor monitors the pressure P1 of the sulfuric acid solution on the inner wall in real time, while the second pressure sensor synchronously monitors the pressure P2 of the heat transfer oil on the outer wall. The control console receives data via Bluetooth and continuously compares and analyzes it. When the difference between P1 and P2 exceeds a preset threshold, the control console automatically adjusts the flow rates of the first and second oil pumps, ensuring that P2 always dynamically follows changes in P1, maintaining the internal and external pressure difference within a safe range. This effectively protects the flexible inner shell from fatigue damage or rupture risks caused by pressure imbalance, improves the reliability and service life of the equipment, ensures good contact between the flexible inner shell and the heat transfer oil, optimizes heat transfer efficiency, reduces the need for manual intervention, and enhances the intelligence and stability of the device operation.

[0026] 4. This invention, by incorporating a protective layer, a heat insulation cavity, a first solenoid valve, a second solenoid valve, static gas, and a gas pump, achieves highly efficient heat insulation between the heat-conducting cavity and the external environment. It solves the problem of insufficient waste heat utilization caused by heat conduction and convection loss through the protective layer during pressure balance control. The protective layer is made of a low thermal conductivity material, initially blocking heat conduction. The heat insulation cavity is filled with a low thermal conductivity static gas or evacuated to a vacuum state. Flexible switching between the two insulation modes is achieved by controlling the first and second solenoid valves and the gas pump. Static gases, such as argon, have slow molecular movement, effectively suppressing heat convection. The vacuum environment blocks heat conduction and convection paths, forming multiple efficient thermal barriers. This maximizes the retention of heat absorbed by the heat-conducting oil within the heat-conducting cavity, ensuring that most of the heat is effectively recovered by transferring it to an external heat exchanger. This improves waste heat recovery efficiency, reduces the surface temperature of the pressure-bearing shell, prevents burns to operators, enhances equipment safety, reduces heat radiation loss, and extends the device's service life. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0028] Figure 2 This is a schematic diagram of the flexible inner shell being pulled out of the pressure-bearing outer shell according to the present invention.

[0029] Figure 3 This is a schematic diagram of the connection structure between the flexible inner shell and the pressure-bearing outer shell of the present invention;

[0030] Figure 4 This is a schematic diagram of the supporting frame structure of the present invention;

[0031] Figure 5This is a schematic diagram of the connection structure between the support frame and the flexible inner shell of the present invention;

[0032] Figure 6 This is a schematic diagram of the pressure-bearing outer shell structure of the present invention;

[0033] Figure 7 This is a cross-sectional view of the pressure-bearing outer shell of the present invention;

[0034] Figure 8 This is a cross-sectional view of the flexible inner shell of the present invention.

[0035] In the diagram: 1. Support frame; 2. Fixing ring; 3. Flexible inner shell; 4. First connecting pipe; 5. Rubber ring; 6. First pressure sensor; 7. Second pressure sensor; 8. Pressure-bearing outer shell; 9. Heat-conducting cavity; 10. Heat-insulating cavity; 11. Protective layer; 12. Second connecting pipe; 13. Oil inlet pipe; 14. Air inlet pipe; 15. Oil outlet pipe; 16. Air outlet pipe; 17. First solenoid valve; 18. Second solenoid valve; 19. First oil pump; 20. Oil delivery pipe; 21. Second oil pump; 22. Static gas; 23. Heat-conducting oil. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0039] Please see Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 An embodiment of the present invention provides an environmentally friendly sulfuric acid continuous flow waste heat recovery device, wherein the protective layer 11 and the pressure-bearing shell 8 form a heat insulation cavity 10, which is filled with static gas 22 with low thermal conductivity. An air inlet pipe 14 is provided at the top of the outer wall of the pressure-bearing shell 8, the top of the air inlet pipe 14 is connected to a first solenoid valve 17, and the bottom of the air inlet pipe 14 is connected to the heat insulation cavity 10. An air outlet pipe 16 is provided at the bottom of the outer wall of the pressure-bearing shell 8, the top of the air outlet pipe 16 is connected to the heat insulation cavity 10, and the bottom of the air outlet pipe 16 is connected to a second solenoid valve 18.

[0040] Furthermore, before the solution reaction, the operator selects the insulation mode via the control panel. The insulation mode is divided into gas insulation and vacuum insulation. When the operator selects the gas insulation mode, the control panel first starts the gas pump through the connecting line and simultaneously opens the first solenoid valve 17 and the second solenoid valve 18. After the gas pump starts, the gas pump pumps the static gas 22 into the insulation chamber 10 through the inlet pipe 14 via the first solenoid valve 17. The static gas 22 is argon gas with low thermal conductivity. The molecular motion rate of argon gas is slow, which can effectively block the heat transfer path. When the insulation chamber 10 is filled with static gas 22, the control panel closes the first solenoid valve 17 and the second solenoid valve 18, so that the insulation chamber 10 forms a sealed gas insulation layer. The low thermal conductivity of the static gas 22 prevents the heat in the heat conduction chamber 9 from being lost to the external pressure-bearing shell 8 through the protective layer 11, thereby improving the waste heat recovery efficiency.

[0041] When the operator selects the vacuum insulation mode, the control panel closes the first solenoid valve 17 via the connecting cable to ensure that external gas cannot enter the insulation chamber 10. Then, the second solenoid valve 18 is opened, and the air pump is started. The air pump draws air out through the air outlet pipe 16, continuously extracting the gas inside the insulation chamber 10, gradually reducing the pressure inside the insulation chamber 10. The vacuum sensor built into the insulation chamber 10 detects the vacuum level inside the insulation chamber 10 in real time and transmits the data to the control panel. When the vacuum level reaches the preset high vacuum standard, such as an absolute pressure below 0.1 Pa, the control panel automatically closes the second solenoid valve 18 and stops the air pump, keeping the insulation chamber 10 in a near-absolute vacuum state. In a vacuum environment, heat conduction and heat convection can be suppressed, ensuring that the heat absorbed by the heat transfer oil 23 from the sulfuric acid reaction solution can be efficiently used for subsequent heat exchange, minimizing heat loss. The vacuum insulation mode is suitable for working conditions with high requirements for waste heat recovery efficiency or for critical process links where the sulfuric acid reaction temperature is extremely high and heat loss is sensitive.

[0042] Please see Figure 1 , Figure 5 , Figure 6 , Figure 7 and Figure 8 An embodiment of the present invention provides an environmentally friendly sulfuric acid continuous flow waste heat recovery device. The pressure-bearing outer shell 8 is provided with a protective layer 11 inside. The protective layer 11 and the outer wall of the flexible inner shell 3 form a heat-conducting cavity 9. The heat-conducting cavity 9 is filled with heat-conducting oil 23. A second pressure sensor 7 detects the pressure exerted by the heat-conducting oil 23 on the outer wall of the flexible inner shell 3. An oil inlet pipe 13 is provided at the top of the outer wall of the pressure-bearing outer shell 8. The bottom end of the oil inlet pipe 13 is connected to the heat-conducting cavity 9. The top end of the oil inlet pipe 13 is connected to a first oil pump 19. An oil outlet pipe 15 is provided at the bottom of the outer wall of the pressure-bearing outer shell 8. The top end of the oil outlet pipe 15 is connected to the heat-conducting cavity 9. The bottom end of the oil outlet pipe 15 is connected to a second oil pump 21.

[0043] Furthermore, after the insulation cavity 10 is filled with gas or evacuated, the operator starts the first oil pump 19 via the control panel. The first oil pump 19 delivers the external low-temperature heat transfer oil 23 to the oil inlet pipe 13 through the oil delivery pipe 20. The oil inlet pipe 13 is connected to the heat transfer cavity 9 through the injection valve. At the same time, the bottom end of the heat transfer cavity 9 is connected to the oil outlet pipe 15 through the discharge valve, forming a complete circulation loop. At this time, the operator inputs the sulfuric acid reaction solution into the flexible inner shell 3 through the first connecting pipe 4. The flexible inner shell 3 is equipped with a support frame 1, which is made of polyetheretherketone (PEEK) material. Polyetheretherketone (PEEK) has high temperature resistance and resistance to concentrated sulfuric acid corrosion. It has high mechanical strength and good dimensional stability. The support frame 1 is closely attached to the inner wall side of the flexible inner shell 3. The hollow structure of the support frame 1 ensures sufficient support strength and minimizes the obstruction to heat transfer. It provides radial support to the soft flexible inner shell 3, preventing the flexible inner shell 3 from collapsing or excessively deforming when impacted by sulfuric acid solution or under pressure fluctuations. This ensures the stability of the flow channel and maintains the cylindrical geometry of the flexible inner shell 3, allowing the heat transfer oil 23 to flow evenly through the heat transfer cavity 9 and ensuring heat exchange efficiency.

[0044] The flexible inner shell 3 is made of polytetrafluoroethylene, which has excellent high temperature resistance and strong resistance to concentrated sulfuric acid corrosion. At the same time, the flexible inner shell 3 is soft and can undergo slight deformation under external pressure, thereby adapting to the pressure changes of the internal sulfuric acid solution. As the sulfuric acid solution is gradually injected, the first pressure sensor 6 on the inner wall side of the flexible inner shell 3 begins to monitor the pressure P1 exerted by the sulfuric acid reaction solution on the inner wall of the flexible inner shell 3 in real time and transmits the data to the control console. At the same time, the second pressure sensor 7 on the outer wall side of the flexible inner shell 3 synchronously monitors the pressure P2 exerted by the heat transfer oil 23 on the outer wall of the flexible inner shell 3 and also transmits the data to the control console. The Bluetooth communication module built into the control console receives the data of pressure P1 and pressure P2 in real time and performs comparative analysis.

[0045] During the sulfuric acid solution injection process, the control console opens the injection valve and simultaneously controls the first oil pump 19 to pump the heat transfer oil 23 into the heat transfer chamber 9 inside the pressure-bearing shell 8. The pressure-bearing shell 8 is made of stainless steel, which has corrosion resistance and high mechanical strength, and can withstand the internal pressure generated during the circulation of the heat transfer oil 23. At the same time, the control console adjusts the input of the heat transfer oil 23 in real time, so that the pressure P2 always dynamically follows the pressure P1, ensuring that the flexible inner shell 3 will not crack or deform due to excessive internal and external pressure difference when subjected to the pressure of the sulfuric acid solution. When the second pressure sensor 7 detects that P2 is greater than P1, and the absolute value of the difference between the two exceeds the preset threshold, the preset threshold is set to 0.01 MPa. The control console issues commands via the connection cable to reduce the input of the first oil pump 19 to the heat transfer oil 23, thereby reducing the pressure inside the heat transfer cavity 9. This causes P2 to gradually decrease until it equals P1. When P2 is less than P1 and the absolute value of the difference exceeds 0.01 MPa, the control console increases the input of the first oil pump 19 to the heat transfer oil 23, increasing the pressure inside the heat transfer cavity 9. This causes P2 to rise to equal P1. This adjustment is repeated until the sulfuric acid reaction solution completely fills the interior of the flexible inner shell 3. At this point, the heat transfer oil 23 also simultaneously fills the heat transfer cavity 9, protecting the structural integrity of the flexible inner shell 3 and preventing mechanical damage caused by pressure imbalance. This lays a safe foundation for subsequent continuous flow waste heat recovery.

[0046] Please see Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 An embodiment of the present invention provides an environmentally friendly sulfuric acid continuous flow waste heat recovery device. The inner wall side of the flexible inner shell 3 is in contact with the outer wall side of the support frame 1. The support frames 1 are fixed by a fixing ring 2. A first pressure sensor 6 is provided on the inner wall side of the flexible inner shell 3. The first pressure sensor 6 detects the pressure exerted by the sulfuric acid reaction solution on the inner wall of the flexible inner shell 3. A first connecting pipe 4 is provided at the top of the outer wall of the flexible inner shell 3. A rubber ring 5 on the outside of the first connecting pipe 4 prevents the leakage of heat transfer oil 23. The thread on the outer wall of the first connecting pipe 4 meshes with the thread groove on the inner wall of the second connecting pipe 12. The second connecting pipe 12 is provided at the top of the outer wall of the pressure-bearing outer shell 8.

[0047] Furthermore, as the sulfuric acid reaction solution continues to undergo a chemical reaction and releases a large amount of heat within the flexible inner shell 3, the heat transfer oil 23 in the heat transfer cavity 9 absorbs the heat released by the reaction, causing the temperature of the heat transfer oil 23 to rise. The operator opens the injection valve and discharge valve through the control panel to fully connect the heat transfer cavity 9 with the external circulation pipeline. Then, the first oil pump 19 and the second oil pump 21 are started simultaneously. The second oil pump 21 extracts the high-temperature heat transfer oil 23 from the heat transfer cavity 9 through the oil outlet pipe 15 and transports it to the external heat exchanger through the oil delivery pipe 20. Inside the heat exchanger, the high-temperature heat transfer oil 23 exchanges heat with the cooling medium, transferring the heat it carries to the cooling medium to achieve waste heat recovery and utilization. After releasing heat, the temperature of the heat transfer oil 23 decreases, becoming low-temperature heat transfer oil 23. Then, it is pumped back into the heat transfer cavity 9 through the oil inlet pipe 13 by the first oil pump 19 to continue absorbing the heat released by the sulfuric acid reaction solution, ensuring that the waste heat generated by the sulfuric acid reaction can be recovered and utilized in a timely and efficient manner.

[0048] During the heat absorption process of the heat transfer oil 23, the protective layer 11 is made of polyimide. Polyimide has a low thermal conductivity and excellent thermal stability, and can work stably in high-temperature environments for a long time without decomposition or deformation. It effectively inhibits heat conduction, making it difficult for the heat in the heat transfer cavity 9 to be transferred to the outside through the protective layer 11. At the same time, the static gas 22, such as argon, or the vacuum state maintained in the heat insulation cavity 10 further blocks the convection and conduction paths of heat. The molecular movement of the static gas 22 is restricted, resulting in low heat exchange efficiency. Thus, a highly efficient thermal barrier is formed between the protective layer 11 and the pressure-bearing shell 8, which surrounds the heat absorbed by the heat transfer oil 23 inside the heat transfer cavity 9, minimizing the loss of heat to the external environment. This ensures that most of the heat is effectively recovered by being transported to the heat exchanger through the second oil pump 21, improving the waste heat recovery efficiency. It also reduces the surface temperature of the pressure-bearing shell 8, avoiding the safety risk of high-temperature burns to operators, while reducing the heat radiation loss of the equipment and extending the service life of the equipment.

[0049] Please see Figure 1 , Figure 3 , Figure 5 , Figure 6 , Figure 7 and Figure 8 An embodiment of the present invention provides an environmentally friendly sulfuric acid continuous flow waste heat recovery device, wherein the first solenoid valve 17, the second solenoid valve 18 and the air pump are all connected to the control console via external connecting lines. The control console has a built-in Bluetooth communication module, and the control console is connected to the first pressure sensor 6 and the second pressure sensor 7 via the Bluetooth communication module. The control console controls the first oil pump 19 and the second oil pump 21 via connecting lines.

[0050] Furthermore, during the stable operation of the continuous flow waste heat recovery device for sulfuric acid, the first pressure sensor 6 on the inner wall side of the flexible inner shell 3 detects the pressure P1 applied by the sulfuric acid reaction solution in real time, while the second pressure sensor 7 on the outer wall side of the flexible inner shell 3 simultaneously detects the pressure P2 applied by the heat transfer oil 23. Both sets of pressure data are transmitted to the control console in real time via a Bluetooth communication module. The microprocessor built into the control console continuously compares and analyzes P1 and P2 to ensure that the pressure difference between them remains within a preset safe range. When the flow rate of the sulfuric acid reaction solution suddenly increases or the reaction intensity changes drastically, P1 may rise rapidly. If the pressure P2 of the heat transfer oil 23 fails to respond in time, P2 will be less than P1. The control console monitors a difference of -0.03 MPa between P2 and P1, meaning P2 is less than P1. The pressure difference is less than 0.03 MPa, while the preset absolute value threshold for the pressure difference is 0.01 MPa. The microprocessor in the control console determines that the current pressure difference has exceeded the safe range. The flexible inner shell 3 is subjected to additional pressure due to outward expansion. Long-term operation may cause fatigue damage or rupture of the flexible inner shell 3. At this time, the control console sends a command to the first oil pump 19 through the connecting line to increase the input of heat transfer oil 23. After receiving the command, the first oil pump 19 quickly increases its speed and pumps more low-temperature heat transfer oil 23 into the heat transfer cavity 9 through the oil inlet pipe 13, thereby rapidly increasing the pressure in the heat transfer cavity 9. When the pressure difference between the inner and outer sides of the flexible inner shell 3 is large and exceeds 0.1 MPa, the control console simultaneously sends a command to the second oil pump 21 to reduce the output of heat transfer oil 23, so that the heat transfer oil 23 in the heat transfer cavity 9 temporarily accumulates and the pressure rises.

[0051] As the input of the first oil pump 19 increases and the output of the second oil pump 21 decreases, the volume of the heat transfer oil 23 in the heat transfer cavity 9 gradually increases, and the pressure P2 begins to rise steadily. The second pressure sensor 7 continuously transmits the real-time change data of P2 to the control console. The control console continuously calculates the difference between P2 and P1. When the absolute value of the difference between P2 and P1 returns to within 0.01 MPa, the control console stops the adjustment command. Finally, the control console adjusts the input of the first oil pump 19 to be exactly equal to the output of the second oil pump 21, so that the heat transfer oil 23 in the heat transfer cavity 9 reaches a dynamic equilibrium state. P2 stabilizes at a level slightly higher than P1 but with an absolute pressure difference of less than 0.01 MPa. At this time, the pressure on the inner and outer sides of the flexible inner shell 3 is restored to equilibrium, the structure is subjected to uniform stress, local stress concentration is avoided, the mechanical integrity of the flexible inner shell 3 is protected, the stable contact between the heat transfer oil 23 and the sulfuric acid reaction solution is ensured, the high efficiency of heat transfer is maintained, and continuous flow dynamic pressure balance control is realized, providing a reliable guarantee for the long-term stable operation of the device.

[0052] Please see Figure 1 , Figure 3 , Figure 5 , Figure 6 , Figure 7 and Figure 8 An embodiment of the present invention provides an environmentally friendly sulfuric acid continuous flow waste heat recovery device, wherein the heat conduction cavity 9 is filled with heat conduction oil 23, the second pressure sensor 7 detects the pressure exerted by the heat conduction oil 23 on the outer wall of the flexible inner shell 3, the top of the outer wall of the pressure-bearing outer shell 8 is provided with an oil inlet pipe 13, the bottom end of the oil inlet pipe 13 is connected to the heat conduction cavity 9, the top end of the oil inlet pipe 13 is connected to the first oil pump 19, the bottom of the outer wall of the pressure-bearing outer shell 8 is provided with an oil outlet pipe 15, the top end of the oil outlet pipe 15 is connected to the heat conduction cavity 9, and the bottom end of the oil outlet pipe 15 is connected to the second oil pump 21;

[0053] Furthermore, as the sulfuric acid solution reaction gradually enters the later stage, the activity of the sulfuric acid reaction solution decreases, the reaction intensity weakens, and the released heat decreases. At this time, the pressure P1 of the sulfuric acid reaction solution inside the flexible inner shell 3 begins to decrease, while the heat transfer oil 23 in the heat transfer cavity 9 maintains the original pressure level, resulting in P2 being relatively high. The first pressure sensor 6 and the second pressure sensor 7 detect P1 and P2 in real time. P1 gradually decreases from 0.32MPa at the peak of the reaction to 0.24MPa, while P2 remains at 0.28MPa. The difference between P1 and P2 is 0.04MPa, that is, P2 is 0.04MPa greater than P1. The preset absolute value threshold of the pressure difference is 0.01MPa. The control console determines that the current pressure difference has exceeded the safe range. The flexible inner shell 3 is subjected to a huge pressure difference from the outside to the inside, that is, the heat transfer oil 23 squeezes the flexible inner shell 3 from the outside to the inside.

[0054] When the control console detects that P2 is greater than P1 and the absolute value of the difference exceeds 0.01MPa, the control console sends a command to the first oil pump 19 to reduce the input of the first oil pump 19 to the heat transfer oil 23. After receiving the command, the first oil pump 19 quickly reduces its speed and reduces the flow rate of the low-temperature heat transfer oil 23 pumped into the heat transfer cavity 9 through the oil inlet pipe 13. When the pressure difference between the inner and outer sides of the flexible inner shell 3 is large and the absolute value of the pressure difference exceeds 0.1MPa, the control console simultaneously sends a command to the second oil pump 21 to increase the output of the heat transfer oil 23, accelerate the extraction of the high-temperature heat transfer oil 23 and deliver it to the external heat exchanger, and effectively reduce the pressure in the heat transfer cavity 9.

[0055] At this point, the pressure on both sides of the flexible inner shell 3 returns to dynamic equilibrium, with neither inward compression nor outward expansion, and is in the optimal mechanical state. Through real-time monitoring and dynamic adjustment, the device can automatically adapt to the natural pressure drop at the end of the reaction, ensuring that the flexible inner shell 3 always operates within a safe pressure range and avoiding compression damage caused by excessive external pressure. At the same time, the balanced P2 pressure also ensures good contact between the heat transfer oil 23 and the outer wall of the flexible inner shell 3, so that although the heat decreases in the later stage of the reaction, the remaining heat can still be efficiently recovered, maximizing energy utilization.

[0056] Working principle: During operation, the sulfuric acid reaction solution enters the flexible inner shell 3 through the first connecting pipe 4. A first pressure sensor 6 is installed on the inner wall side of the flexible inner shell 3. The first pressure sensor 6 detects the pressure P1 applied by the solution to the inner wall of the flexible inner shell 3 in real time. A heat conduction cavity 9 is formed between the outer side of the flexible inner shell 3 and the pressure-bearing outer shell 8. The heat conduction cavity 9 is filled with heat conduction oil 23. A second pressure sensor 7 detects the pressure P2 applied by the heat conduction oil 23 to the outer wall of the flexible inner shell 3 in real time. The control console receives the P1 and P2 data through the Bluetooth module and dynamically adjusts the start-up and stop and flow rate of the first oil pump 19 and the second oil pump 21 so that P2 always dynamically follows P1, ensuring that the absolute value of the pressure difference between the inside and outside of the flexible inner shell 3 is less than a preset threshold, thereby protecting the flexible inner shell 3 from mechanical damage caused by pressure imbalance.

[0057] The heat released by the sulfuric acid reaction is transferred to the heat transfer oil 23 through the flexible inner shell 3. The high-temperature heat transfer oil 23 is transported to the external heat exchanger by the second oil pump 21 through the oil outlet pipe 15 for heat exchange. After releasing heat, the low-temperature heat transfer oil 23 is pumped back to the heat transfer cavity 9 by the first oil pump 19 through the oil inlet pipe 13, forming a continuous circulation heat exchange. At the same time, the heat insulation cavity 10 between the protective layer 11 and the pressure-bearing outer shell 8 is filled with a static gas 22 with a low thermal conductivity or evacuated to a vacuum, which can effectively block the heat conduction and convection to the outside, minimize heat loss, improve waste heat recovery efficiency, and achieve safe, efficient and continuous heat energy recovery.

[0058] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. An environmentally friendly continuous flow waste heat recovery device for sulfuric acid, comprising a flexible inner shell (3) and a pressure-bearing outer shell (8), characterized in that: The flexible inner shell (3) is provided with a support frame (1) inside. The flexible inner shell (3) is filled with sulfuric acid reaction solution. The flexible inner shell (3) is connected to the pressure-bearing outer shell (8) through the first connecting pipe (4) at the top. Heat transfer oil (23) is provided between the protective layer (11) inside the pressure-bearing outer shell (8) and the flexible inner shell (3). Static gas (22) is provided between the protective layer (11) and the inner wall of the pressure-bearing outer shell (8). The first pressure sensor (6) and the second pressure sensor (7) on the inner and outer sides of the flexible inner shell (3) respectively detect the pressure applied by the sulfuric acid reaction solution and the heat transfer oil (23). The first oil pump (19) at the top of the pressure-bearing outer shell (8) delivers low-temperature heat transfer oil (23) through the oil inlet pipe (13). The second oil pump (21) at the bottom of the pressure-bearing outer shell (8) outputs high-temperature heat transfer oil (23) through the oil outlet pipe (15).

2. The environmentally friendly continuous flow sulfuric acid waste heat recovery device according to claim 1, characterized in that: The inner wall side of the flexible inner shell (3) is in contact with the outer wall side of the support frame (1). The support frames (1) are fixed together by a fixing ring (2). A first pressure sensor (6) is provided on the inner wall side of the flexible inner shell (3). The first pressure sensor (6) detects the pressure applied by the sulfuric acid reaction solution to the inner wall of the flexible inner shell (3).

3. The environmentally friendly continuous flow sulfuric acid waste heat recovery device according to claim 2, characterized in that: The flexible inner shell (3) has a first connecting pipe (4) at the top of its outer wall. A rubber ring (5) is provided on the side of the outer wall of the first connecting pipe (4). The thread on the outer wall of the first connecting pipe (4) meshes with the thread groove on the inner wall of the second connecting pipe (12). The second connecting pipe (12) is located at the top of the outer wall of the pressure-bearing outer shell (8).

4. The environmentally friendly continuous flow sulfuric acid waste heat recovery device according to claim 3, characterized in that: The pressure-bearing outer shell (8) is provided with a protective layer (11), and a heat-conducting cavity (9) is formed between the protective layer (11) and the outer wall of the flexible inner shell (3). The heat-conducting cavity (9) is filled with heat-conducting oil (23). A second pressure sensor (7) is provided on the side of the outer wall of the flexible inner shell (3). The second pressure sensor (7) detects the pressure exerted by the heat-conducting oil (23) on the outer wall of the flexible inner shell (3).

5. The environmentally friendly continuous flow sulfuric acid waste heat recovery device according to claim 4, characterized in that: The pressure-bearing shell (8) has an oil inlet pipe (13) at the top of its outer wall. The bottom of the oil inlet pipe (13) is connected to the heat conduction cavity (9). The top of the oil inlet pipe (13) is connected to the first oil pump (19). The bottom of the pressure-bearing shell (8) has an oil outlet pipe (15). The top of the oil outlet pipe (15) is connected to the heat conduction cavity (9). The bottom of the oil outlet pipe (15) is connected to the second oil pump (21). The first oil pump (19) and the second oil pump (21) are both equipped with oil delivery pipes (20). The first oil pump (19) and the second oil pump (21) are connected to the external heat exchanger through the oil delivery pipes (20).

6. The environmentally friendly continuous flow sulfuric acid waste heat recovery device according to claim 5, characterized in that: The protective layer (11) inside the pressure-bearing shell (8) is made of a low thermal conductivity material. The protective layer (11) and the inner wall of the pressure-bearing shell (8) form a heat insulation cavity (10), which is filled with static gas (22).

7. The environmentally friendly continuous flow sulfuric acid waste heat recovery device according to claim 6, characterized in that: An air inlet pipe (14) is provided at the top of the outer wall of the pressure-bearing shell (8). The top of the air inlet pipe (14) is connected to the first solenoid valve (17), and the bottom of the air inlet pipe (14) is connected to the heat insulation cavity (10). An air outlet pipe (16) is provided at the bottom of the outer wall of the pressure-bearing shell (8). The top of the air outlet pipe (16) is connected to the heat insulation cavity (10), and the bottom of the air outlet pipe (16) is connected to the second solenoid valve (18). The air pump is connected to the air inlet pipe (14) through the first solenoid valve (17), and the air pump is connected to the air outlet pipe (16) through the second solenoid valve (18).

8. The environmentally friendly continuous flow sulfuric acid waste heat recovery device according to claim 7, characterized in that: The first solenoid valve (17), the second solenoid valve (18) and the air pump are all connected to the control console via external connecting lines. The control console has a built-in Bluetooth communication module. The control console is connected to the first pressure sensor (6) and the second pressure sensor (7) via the Bluetooth communication module. The control console controls the first oil pump (19) and the second oil pump (21) via connecting lines.

9. An environmentally friendly continuous flow sulfuric acid waste heat recovery method, applicable to the environmentally friendly continuous flow sulfuric acid waste heat recovery device according to any one of claims 1-8, characterized in that: The waste heat recovery method includes the following steps: S1. Connect the first connecting pipe (4) of the flexible inner shell (3) to the second connecting pipe (12) of the pressure-bearing outer shell (8) by threading and seal it with a rubber ring (5). Then inject heat transfer oil (23) into the heat transfer cavity (9) through the oil inlet pipe (13) until the heat transfer oil (23) completely fills the heat transfer cavity (9) between the flexible inner shell (3) and the protective layer (11). S2. The control console starts the air pump and opens the first solenoid valve (17), and fills the insulation cavity (10) with static gas (22) with low thermal conductivity through the air inlet pipe (14). The control console can also perform vacuum treatment on the insulation cavity (10) through the second solenoid valve (18) and the air outlet pipe (16) to reduce the thermal conductivity of the gas in the insulation cavity (10) and reduce the heat loss of the heat conduction cavity (9) to the pressure shell (8) through the protective layer (11). S3. The pressure on the inside and outside of the flexible inner shell (3) is dynamically adjusted by the pressure data detected by the first pressure sensor (6) and the second pressure sensor (7) to balance the pressure on the inside and outside of the flexible inner shell (3). At the same time, the heat of the sulfuric acid reaction solution is transferred through the flexible inner shell (3) to the heat transfer oil (23) in the heat transfer cavity (9). After the heat transfer oil (23) absorbs heat, its temperature rises. The second oil pump (21) extracts the high temperature heat transfer oil (23) through the oil outlet pipe (15) and delivers it to the external heat exchanger for heat exchange. The low temperature heat transfer oil (23) that releases heat is transported back to the heat transfer cavity (9) through the first oil pump (19) and the oil inlet pipe (13) to form a continuous cycle of heat exchange.

10. The environmentally friendly continuous flow waste heat recovery method for sulfuric acid according to claim 9, characterized in that: The waste heat recovery method further includes the following steps: S31. When adjusting the pressure on the inner and outer sides of the flexible inner shell (3), the control console connects the first pressure sensor (6) and the second pressure sensor (7) to detect the pressure P1 applied to the inner wall of the flexible inner shell (3) by the sulfuric acid reaction solution and the pressure P2 applied to the outer wall of the flexible inner shell (3) by the heat transfer oil (23) in real time. The control console receives the data of P1 and P2 and controls the start-up and stop and flow rate of the first oil pump (19) and the second oil pump (21) through the connecting line, and adjusts the input and output of the heat transfer oil (23) so that P2 always dynamically follows P1 and keeps the absolute value of the pressure difference between P1 and P2 less than the preset threshold.

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