A shell-and-tube heat exchanger for producing persulfate
By combining four cooling groups and three baffles with three valves, the problem of untimely temperature control in persulfate production using tube heat exchangers was solved, achieving flexible temperature control and reduced energy consumption, thus improving product quality and motor life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- FUJIAN ZHANHUA CHEM
- Filing Date
- 2026-07-06
- Publication Date
- 2026-07-31
AI Technical Summary
Existing tube heat exchangers are difficult to control in real time during persulfate production, leading to localized overheating or undercooling, which affects product quality and motor lifespan, and also results in high energy consumption.
The design employs four cooling groups and three baffles combined with three valves, allowing for flexible switching between four heat exchange modes (level one to level four), precise temperature control, reduced flow resistance, and lower motor control requirements.
It enables timely temperature control during the persulfate production process, reducing energy consumption and maintenance difficulty, extending motor lifespan, and improving product quality and production efficiency.
Smart Images
Figure CN122486384A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of heat exchanger technology, and specifically to a tube heat exchanger for persulfate production. Background Technology
[0002] Persulfates (such as ammonium persulfate and sodium persulfate) are important chemical raw materials, widely used in polymer initiators, electronic etching, and soil remediation. During the production of persulfates (usually via electrolysis or chemical oxidation), the reaction releases a large amount of heat, and the persulfate solution itself is highly unstable. Improper temperature control can easily lead to thermal decomposition of the persulfate, or excessively low temperatures can result in insufficient reaction, not only reducing product yield but also potentially triggering a severe risk of exothermic runaway.
[0003] Currently, cooling in persulfate production lines typically employs traditional shell-and-tube heat exchangers. However, traditional shell-and-tube heat exchangers face the following limitations in existing technology during persulfate production: The fixed heat exchange path of a shell-and-tube heat exchanger means that the heat exchange fluid supplied can only be at a fixed temperature. Temperature changes can only be controlled by adjusting the flow rate of the heat exchange fluid through the speed of the heat exchange fluid circulation pump motor. However, existing shell-and-tube heat exchangers, in order to improve heat exchange efficiency, require the heat exchange fluid to travel a long path, resulting in a delayed temperature control response. This means that the flow rate of the heat exchange fluid and the heat released by the reaction are difficult to match in real time, leading to local overheating or undercooling. This affects the uniformity of crystal precipitation and product purity, and consequently affects the production and quality of persulfate.
[0004] Furthermore, the constant and significant changes in motor power increase energy consumption, and these uneven power fluctuations also impact bearings, causing rotor wear and fatigue, which in turn shortens the motor's lifespan.
[0005] Therefore, there is a need for a tube heat exchanger for persulfate production that can reduce the requirements for motor control and can provide timely temperature control based on the actual production temperature. Summary of the Invention
[0006] The technical problem to be solved by the present invention is to provide a tube heat exchanger for persulfate production that can control flow without a motor and can respond to temperature control in a timely manner according to the actual production temperature.
[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A tube heat exchanger for persulfate production includes a cooling section and a heat exchange section; The cooling section includes a cooling cylinder and four cooling groups. The cooling cylinder has sealing partitions at both ends. The four cooling groups are arranged parallel to each other inside the cooling cylinder and are spaced apart. Each cooling group includes multiple cooling pipes with openings at both ends, and the openings extend outside the sealing partitions at both ends of the cooling cylinder. The four cooling groups are numbered from top to bottom as Group 1, Group 2, Group 3, and Group 4. The side wall of the cooling cylinder has cooling inlets and cooling outlets for coolant to pass through. The heat exchange section includes a first heat exchange chamber and a second heat exchange chamber respectively sealed and connected to both ends of the cooling cylinder. The first heat exchange chamber has a heat exchange inlet at the top for the inflow of heat exchange fluid and a heat exchange outlet at the bottom for the outflow of heat exchange fluid. The first heat exchange chamber has an upper partition and a lower partition arranged vertically. The second heat exchange chamber has a middle partition. The upper partition cooperates with the sealing partitions between the first and second groups to form a partition. The lower partition cooperates with the sealing partitions between the third and fourth groups to form a partition. The middle partition cooperates with the sealing partitions between the second and third groups to form a partition. A first valve is provided on the upper partition, a third valve is provided on the lower partition, and a second valve is provided on the middle partition. The tube-and-shell heat exchanger includes four stages of heat exchange: In the primary heat exchange, the first and third valves are open simultaneously, and the coolant does not pass through the cooling group. Two-stage heat exchange employs any one of the following methods: only the first valve is open, only the second valve is open, only the third valve is open, or both the second and third valves are open simultaneously, with the coolant passing through two of the cooling groups. In a three-stage heat exchange system, the first and third valves are opened alternately. When the coolant passes through two of the cooling groups, the other two cooling groups serve as cold storage groups. The coolant alternates between the cooling groups and the cold storage groups. The four-stage heat exchange system employs any of the following methods: closing only the first valve, closing only the third valve, or closing all three valves simultaneously. The coolant passes through four cooling groups.
[0008] Preferably, the time interval between the opening of the first valve and the third valve is twice the length of the cooling pipe divided by the current flow rate of the heat exchange fluid.
[0009] Preferably, in the case of secondary heat exchange, one of the two methods, namely opening only the first valve or opening only the third valve, is preferred.
[0010] Preferably, in the case of four-stage heat exchange, one of the two methods, namely closing only the first valve or closing only the third valve, is preferred; After a complete production cycle of persulfate is completed, the process switches to one of the two methods.
[0011] Preferably, the heat exchange inlet, heat exchange outlet, first valve, and third valve are arranged coaxially.
[0012] Preferably, the sealing partition is provided with a through hole for the cooling pipe to pass through; The openings at both ends of the cooling pipe extend through through holes to the sealing partitions at both ends of the cooling cylinder; the outer surface of the cooling pipe is welded and sealed to the corresponding through holes of the sealing partition.
[0013] Preferably, the cooling cylinder is provided with several temperature sampling ports.
[0014] Preferably, each cooling group has the same number of cooling pipes.
[0015] Preferably, the cooling inlet and cooling outlet are located on the side walls near both ends of the cooling cylinder.
[0016] Preferably, the outer wall of the cooling cylinder is provided with a heat insulation layer.
[0017] The beneficial effects of this invention are as follows: Through the combination of four cooling groups, three baffles, and three valves, four different heat exchange modes (level one to four) can be flexibly switched according to different stages of persulfate production (such as initial heating, vigorous reaction period, and stable period). One device covers four operating conditions, precisely controlling the material temperature and preventing overheating leading to side reactions or undercooling leading to insufficient reaction or crystallization. Except for the long path in the level four heat exchange case, the flow resistance is lower in other heat exchange scenarios; valves can be switched as needed, resulting in faster temperature control response; and there is no need to change the external structure of the existing heat exchanger or the existing pipeline layout, nor is it necessary to add additional external pipelines, transfer pumps, or multiple heat exchangers in series, reducing modification costs. The operation and maintenance difficulty is far lower than traditional multi-unit heat exchange schemes, and the control requirements, load, and impact on the heat exchange liquid circulation pump motor are reduced, extending its service life.
[0018] By using upper, middle, and lower partitions in conjunction with first to third valves, the heat exchange contact area and path can be adjusted. By selecting the appropriate valves, the contact area can be reduced by shortening the path or increased by lengthening the path. For example: In the first-stage heat exchange, the first and second valves are opened, allowing the heat exchange fluid to bypass any cooling pipes, reducing the contact area and stabilizing the temperature of the heat exchange fluid to meet the requirements of the persulfate steady-state period, while also reducing flow resistance. In two-stage heat exchange, the heat exchange fluid only passes through two sets of cooling groups, which can be carried out when the cooling capacity requirement is not large during the initial heating, while reducing flow resistance. In three-stage heat exchange, there may be sudden and brief thermal runaway (rapid temperature rise) during the initial heating and stabilization period. If you switch directly to four-stage heat exchange, the path is long, the flow resistance is high, the response time is long, and the cooling capacity may be too large, making it difficult to adjust. In this case, using three-stage heat exchange allows the heat exchange fluid in the other two cooling groups to be used as a cold storage group. Switching back and forth, the flow resistance remains basically unchanged, which reduces motor impact and improves the cooling effect. The heat exchange fluid in the cold storage group has a longer cooling time, which can make the heat exchange fluid temperature lower. And since it only passes through two cooling groups, the response time is short, which makes it easier to deal with emergencies. In a four-stage heat exchange, the heat exchange fluid passes through four sets of cooling groups, which can meet the large cooling requirements during the period of intense reaction. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of a shell-and-tube heat exchanger for persulfate production according to a specific embodiment of the present invention; Figure 2 This is a partial disassembly diagram of a tube-and-shell heat exchanger for persulfate production according to a specific embodiment of the present invention, taken from a first angle. Figure 3 This is a partial disassembly diagram of a tube-and-shell heat exchanger for persulfate production according to a specific embodiment of the present invention, taken from a second angle. Figure 4 This is a partial disassembly diagram of a tube-and-shell heat exchanger for persulfate production according to a specific embodiment of the present invention, taken from a third-angle perspective. Figure 5 This is a schematic diagram of the first-stage heat exchange of a shell-and-tube heat exchanger for persulfate production according to a specific embodiment of the present invention (blue arrows indicate the flow direction of cooling water, and red arrows indicate the flow direction of heat exchange fluid, the same below); Figure 6 This is a schematic diagram of the first secondary heat exchange of a shell-and-tube heat exchanger for persulfate production according to a specific embodiment of the present invention; Figure 7 This is a schematic diagram of a second-stage heat exchanger for a tube-and-shell heat exchanger used in persulfate production, according to a specific embodiment of the present invention. Figure 7 and Figure 8 (Switching between three-stage heat exchangers; the green box indicates the cold storage group). Figure 8 This is a schematic diagram of a third-stage heat exchanger for a tube-and-shell heat exchanger used in persulfate production, according to a specific embodiment of the present invention. Figure 7 and Figure 8 (Switching between three-stage heat exchangers; the green box indicates the cold storage group). Figure 9 This is a schematic diagram of the first type of four-stage heat exchange in a shell-and-tube heat exchanger for persulfate production according to a specific embodiment of the present invention. Figure 10This is a schematic diagram of a second type of four-stage heat exchange in a shell-and-tube heat exchanger for persulfate production according to a specific embodiment of the present invention; Figure 11 This is a schematic diagram of a third type of four-stage heat exchange in a shell-and-tube heat exchanger for persulfate production according to a specific embodiment of the present invention; Label Explanation: 1. Cooling section; 11. Cooling cylinder; 12. Sealing partition; 13. First group; 14. Second group; 15. Third group; 16. Fourth group; 17. Cooling inlet; 18. Cooling outlet; 19. Sampling port; 2. Heat exchange section; 21. First heat exchange chamber; 211. Heat exchange inlet; 212. Heat exchange outlet; 22. Second heat exchange chamber; 23. Upper partition; 24. Lower partition; 25. Middle partition; 26. First valve; 27. Third valve; 28. Second valve; 3. Cold storage group. Detailed Implementation
[0020] To explain in detail the technical content, objectives, and effects of the present invention, the following description is provided in conjunction with the embodiments and accompanying drawings.
[0021] Please refer to Figures 1 to 11 A tube heat exchanger for persulfate production includes a cooling section 1 and a heat exchange section 2; The cooling section 1 includes a cooling cylinder 11 and four cooling groups. The cooling cylinder 11 has sealing partitions 12 at both ends. The four cooling groups are arranged parallel to each other inside the cooling cylinder 11 and are spaced apart. Each cooling group includes multiple cooling pipes with openings at both ends, and the openings extend out of the sealing partitions 12 at both ends of the cooling cylinder 11. The four cooling groups are, from top to bottom, the first group 13, the second group 14, the third group 15, and the fourth group 16. The side wall of the cooling cylinder 11 is provided with a cooling inlet 17 and a cooling outlet 18 for the coolant to pass through. The heat exchange section 2 includes a first heat exchange chamber 21 and a second heat exchange chamber 22 respectively sealed and connected to both ends of the cooling cylinder 11. The first heat exchange chamber 21 has a heat exchange inlet 211 at the top for the inflow of heat exchange liquid and a heat exchange outlet 212 at the bottom for the outflow of heat exchange liquid. The first heat exchange chamber 21 has an upper partition 23 and a lower partition 24 arranged vertically. The second heat exchange chamber 22 has a middle partition 25. The upper partition 23 cooperates with the sealing partition 12 between the first group 13 and the second group 14 to form a partition. The lower partition 24 cooperates with the sealing partition 12 between the third group 15 and the fourth group 16 to form a partition. The middle partition 25 cooperates with the sealing partition 12 between the second group 14 and the third group 15 to form a partition. A first valve 26 is provided on the upper partition 23, a third valve 27 is provided on the lower partition 24, and a second valve 28 is provided on the middle partition 25. The tube-and-shell heat exchanger includes four stages of heat exchange: In the primary heat exchange, the first valve 26 and the third valve 27 are opened simultaneously, and the coolant does not pass through the cooling group. The two-stage heat exchanger uses any one of the following methods: only the first valve 26 is open, only the second valve 28 is open, only the third valve 27 is open, or both the second valve 28 and the third valve 27 are open simultaneously. The coolant passes through two of the cooling groups. In a three-stage heat exchange, the first valve 26 and the third valve 27 are opened alternately. When the coolant passes through two of the cooling groups, the other two cooling groups serve as the cold storage group 3. The coolant alternates between the cooling group and the cold storage group 3. The four-stage heat exchange system employs any of the following methods: only the first valve 26 is closed, only the third valve 27 is closed, or all three valves are closed simultaneously. The coolant passes through four cooling groups.
[0022] As described above, the combination of four cooling groups, three baffles, and three valves allows for flexible switching between four different heat exchange modes (level one to four) according to different stages of persulfate production (such as initial heating, vigorous reaction period, and stable period). One unit covers four operating conditions, precisely controlling material temperature and preventing overheating leading to side reactions or undercooling leading to insufficient reaction or crystallization. Except for the long path in the level four heat exchange case, flow resistance is lower in other heat exchange scenarios; valves can be switched as needed, resulting in faster temperature control response; and there is no need to change the existing external structure of the heat exchanger or the existing piping layout, nor to add additional external piping, transfer pumps, or multiple heat exchangers in series, reducing modification costs. Maintenance difficulty is far lower than traditional multi-unit heat exchange schemes, and the control requirements, load, and impact on the heat exchange fluid circulation pump motor are reduced, extending its service life.
[0023] By using the upper partition 23, middle partition 25, and lower partition 24 in conjunction with the first to third valves 27, the heat exchange contact area and path can be adjusted. By selecting the valves, the path can be shortened to reduce the contact area or lengthened to increase the contact area. For example: In the first-stage heat exchange, the first valve 26 and the second valve 28 are opened, so that the heat exchange fluid does not pass through any cooling pipes, reducing the contact area and stabilizing the temperature of the heat exchange fluid to meet the requirements of the persulfate steady-state period, while reducing flow resistance. In two-stage heat exchange, the heat exchange fluid only passes through two sets of cooling groups, which can be carried out when the cooling capacity requirement is not large during the initial heating, while reducing flow resistance. In three-stage heat exchange, there may be sudden and brief thermal runaway (rapid temperature rise) during the initial heating and stabilization period. If you switch directly to four-stage heat exchange, the path is long, the flow resistance is large, the response time is long, and the cooling capacity may be too large, which is difficult to adjust. In this case, three-stage heat exchange can be used as the heat exchange fluid in the other two cooling groups as the cold storage group 3. The flow resistance remains basically unchanged when switching back and forth, which reduces the impact on the motor and improves the cooling effect. The heat exchange fluid in the cold storage group 3 has a longer cooling time, which can make the heat exchange fluid temperature lower. Moreover, it only needs to pass through two cooling groups, and the response time is short, which makes it easier to deal with emergencies. In a four-stage heat exchange, the heat exchange fluid passes through four sets of cooling groups, which can meet the large cooling requirements during the period of intense reaction.
[0024] Furthermore, the time interval between the opening of the first valve 26 and the third valve 27 is twice the length of the cooling pipe divided by the current flow rate of the heat exchange fluid.
[0025] As can be seen from the above description, by dividing twice the length of the cooling pipe by the current flow rate of the heat exchange fluid, i.e., 2 × cooling pipe length ÷ current flow rate of the heat exchange fluid = switching time, it can be ensured that the two cooling groups being switched have sufficient cooling capacity.
[0026] Furthermore, during secondary heat exchange, one of the two methods should be selected: opening only the first valve 26 or opening only the third valve 27.
[0027] As can be seen from the above description, by selecting either the first valve 26 to be opened only or the third valve 27 to be opened only, it is possible to switch to the three-stage heat exchange situation in a timely manner, thereby improving the response speed.
[0028] Furthermore, in the case of four-stage heat exchange, one of the following two methods should be preferred: closing only the first valve 26 or closing only the third valve 27. After a complete production cycle of persulfate is completed, the process switches to one of the two methods.
[0029] As can be seen from the above description, by using one of the two methods of closing only the first valve 26 or only the third valve 27 as the fourth-stage heat exchange, and switching after the persulfate completes one full production cycle, the flow directions of the second group 14 and the third group 15 of the cooling group are opposite due to the switching of these two methods, backflushing is achieved, which can reduce the probability of scale and crystallization of the heat exchange fluid on the inner surface of the cooling tube, thereby extending the maintenance cycle interval and reducing the probability of poor heat exchange effect due to scale and crystallization in the next cycle.
[0030] Furthermore, the heat exchange inlet 211, heat exchange outlet 212, first valve 26, and third valve 27 are coaxially arranged.
[0031] As can be seen from the above description, the heat exchange inlet 211, heat exchange outlet 212, first valve 26, and third valve 27, which are arranged coaxially, facilitate the passage of heat exchange fluid with low resistance during the first-stage heat exchange, reduce the load on the coolant circulation pump, and reduce contact with the already cooled heat exchange fluid.
[0032] Furthermore, the sealing partition 12 is provided with through holes for the cooling pipe to pass through; The openings at both ends of the cooling pipe extend through through holes to the sealing partitions 12 at both ends of the cooling cylinder 11; the outer surface of the cooling pipe is welded and sealed to the corresponding through holes of the sealing partitions 12.
[0033] As can be seen from the above description, welding can improve the sealing effect and prevent failure during long-term high and low temperature changes, thus avoiding the mixing and mutual contamination of coolant and heat exchange fluid.
[0034] Furthermore, the cooling cylinder 11 is provided with several temperature sampling ports 19.
[0035] Furthermore, each cooling group has the same number of cooling pipes.
[0036] As can be seen from the above description, by having the same number of cooling pipes in each group, the heat exchange effect is similar. This reduces the need to calculate the cooling capacity of each heat exchange group when switching between different levels of heat exchange. Instead, the calculation is done directly by multiples, improving switching efficiency and ensuring the consistency of cooling capacity in three-stage heat exchange.
[0037] Furthermore, the cooling inlet 17 and the cooling outlet 18 are located on the side walls near both ends of the cooling cylinder 11.
[0038] As can be seen from the above description, the cooling effect is improved by setting the cooling inlet 17 and the cooling outlet 18 at the furthest distance.
[0039] Furthermore, the outer wall of the cooling cylinder 11 is provided with a heat insulation layer.
[0040] As can be seen from the above description, the heat insulation layer can reduce the loss of cold energy and improve the cooling effect; while the first heat exchange chamber 21 and the second heat exchange chamber 22 do not need a heat insulation layer because the heat exchange fluid is generally at a higher temperature and needs more heat dissipation.
[0041] Example 1 A tube heat exchanger for persulfate production includes a cooling section 1 and a heat exchange section 2; The cooling section 1 includes a cooling cylinder 11 and four sets of cooling groups. The cooling cylinder 11 has cooling inlets 17 and cooling outlets 18 on its side walls for coolant to pass through. The cooling inlets 17 and cooling outlets 18 are located on the side walls near both ends of the cooling cylinder 11. The cooling cylinder 11 is provided with several temperature sampling ports 19. The outer wall of the cooling cylinder 11 is provided with a heat insulation layer.
[0042] The cooling cylinder 11 has sealing partitions 12 at both ends, and the sealing partitions 12 are provided with through holes for the cooling pipes to pass through; Four cooling groups are arranged parallel to each other inside the cooling cylinder 11, with intervals between them. From top to bottom, the four cooling groups are group 13, group 14, group 15, and group 16. Each cooling group includes multiple cooling pipes, and the number of cooling pipes in each group is the same. The cooling pipes have openings at both ends, and the openings at both ends of the cooling pipes extend through through holes to the sealing partitions 12 at both ends of the cooling cylinder 11. The outer surface of the cooling pipes is welded and sealed to the corresponding through holes of the sealing partitions 12.
[0043] The heat exchange section 2 includes a first heat exchange chamber 21 and a second heat exchange chamber 22 respectively sealed and connected to both ends of the cooling cylinder 11. The first heat exchange chamber 21 has a heat exchange inlet 211 at the top for the inflow of heat exchange liquid and a heat exchange outlet 212 at the bottom for the outflow of heat exchange liquid. The first heat exchange chamber 21 has an upper partition 23 and a lower partition 24 arranged vertically. The second heat exchange chamber 22 has a middle partition 25. The upper partition 23 cooperates with the sealing partition 12 between the first group 13 and the second group 14 to form a partition. The lower partition 24 cooperates with the sealing partition 12 between the third group 15 and the fourth group 16 to form a partition. The middle partition 25 cooperates with the sealing partition 12 between the second group 14 and the third group 15 to form a partition. A first valve 26 is provided on the upper partition 23, a third valve 27 is provided on the lower partition 24, and a second valve 28 is provided on the middle partition 25. The heat exchange inlet 211, heat exchange outlet 212, first valve 26, and third valve 27 are arranged coaxially.
[0044] Example 2 A tube-and-shell heat exchanger for persulfate production, as described in Embodiment 1, includes a four-stage heat exchange process: In the primary heat exchange, the first valve 26 and the third valve 27 are opened simultaneously, and the coolant does not pass through the cooling group. The two-stage heat exchange adopts any one of the following methods: only the first valve 26 is open, only the second valve 28 is open, only the third valve 27 is open, or both the second valve 28 and the third valve 27 are open simultaneously. The coolant passes through two of the cooling groups. The preferred method is either only the first valve 26 or only the third valve 27.
[0045] In a three-stage heat exchange system, the first valve 26 and the third valve 27 are opened alternately. When the coolant passes through two of the cooling groups, the other two cooling groups serve as the cold storage group 3. The coolant alternates between the cooling groups and the cold storage group 3. The time interval between the opening of the first valve 26 and the third valve 27 is twice the length of the cooling pipe divided by the current flow rate of the heat exchange fluid.
[0046] The four-stage heat exchange system employs one of the following methods: closing only the first valve 26, closing only the third valve 27, or closing all three valves simultaneously. The coolant passes through four cooling groups. The preferred method is either closing only the first valve 26 or closing only the third valve 27; and after a complete persulfate production cycle, the system switches to the other method.
[0047] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.
Claims
1. A tube-and-shell heat exchanger for persulfate production, characterized in that, Includes cooling and heat exchange sections; The cooling section includes a cooling cylinder and four cooling groups. The cooling cylinder has sealing partitions at both ends. The four cooling groups are arranged parallel to each other inside the cooling cylinder and are spaced apart. Each cooling group includes multiple cooling pipes with openings at both ends, and the openings extend outside the sealing partitions at both ends of the cooling cylinder. The four cooling groups are numbered from top to bottom as Group 1, Group 2, Group 3, and Group 4. The side wall of the cooling cylinder has cooling inlets and cooling outlets for coolant to pass through. The heat exchange section includes a first heat exchange chamber and a second heat exchange chamber respectively sealed and connected to both ends of the cooling cylinder. The first heat exchange chamber has a heat exchange inlet at the top for the inflow of heat exchange fluid and a heat exchange outlet at the bottom for the outflow of heat exchange fluid. The first heat exchange chamber has an upper partition and a lower partition arranged vertically. The second heat exchange chamber has a middle partition. The upper partition cooperates with the sealing partitions between the first and second groups to form a partition. The lower partition cooperates with the sealing partitions between the third and fourth groups to form a partition. The middle partition cooperates with the sealing partitions between the second and third groups to form a partition. A first valve is provided on the upper partition, a third valve is provided on the lower partition, and a second valve is provided on the middle partition. The tube-and-shell heat exchanger includes four stages of heat exchange: In the primary heat exchange, the first and third valves are open simultaneously, and the coolant does not pass through the cooling group. Two-stage heat exchange employs any one of the following methods: only the first valve is open, only the second valve is open, only the third valve is open, or both the second and third valves are open simultaneously, with the coolant passing through two of the cooling groups. In a three-stage heat exchange system, the first and third valves are opened alternately. When the coolant passes through two of the cooling groups, the other two cooling groups serve as cold storage groups. The coolant alternates between the cooling groups and the cold storage groups. The four-stage heat exchange system employs any of the following methods: closing only the first valve, closing only the third valve, or closing all three valves simultaneously. The coolant passes through four cooling groups.
2. The tube heat exchanger for persulfate production according to claim 1, characterized in that, The time interval between the opening of the first valve and the third valve is twice the length of the cooling pipe divided by the current flow rate of the heat exchange fluid.
3. The tube heat exchanger for persulfate production according to claim 1, characterized in that, For two-stage heat exchange, one of the two methods should be selected: opening only the first valve or opening only the third valve.
4. The tube heat exchanger for persulfate production according to claim 1, characterized in that, For four-stage heat exchange, one of the two methods, namely closing only the first valve or closing only the third valve, should be preferred. After a complete production cycle of persulfate is completed, the process switches to one of the two methods.
5. The tube heat exchanger for persulfate production according to claim 1, characterized in that, The heat exchange inlet, heat exchange outlet, first valve, and third valve are arranged coaxially.
6. The tube heat exchanger for persulfate production according to claim 1, characterized in that, The sealing partition is provided with through holes for the cooling pipes to pass through; The openings at both ends of the cooling pipe extend through through holes to the sealing partitions at both ends of the cooling cylinder; the outer surface of the cooling pipe is welded and sealed to the corresponding through holes of the sealing partition.
7. The tube heat exchanger for persulfate production according to claim 1, characterized in that, The cooling cylinder is equipped with several temperature sampling ports.
8. The tube heat exchanger for persulfate production according to claim 1, characterized in that, The number of cooling pipes in each cooling group is the same.
9. The tube heat exchanger for persulfate production according to claim 1, characterized in that, The cooling inlet and cooling outlet are located on the side walls near both ends of the cooling cylinder.
10. The tube heat exchanger for persulfate production according to claim 1, characterized in that, The outer wall of the cooling cylinder is provided with a heat insulation layer.