A heat exchange system, method and apparatus
By controlling the pressure and level of the cold medium and utilizing its boiling point characteristics under different pressures, the problem of pressure instability during liquid nitrogen heat exchange was solved, achieving efficient heat exchange and process stability, and improving product yield and energy utilization efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHONGHAO GUANGMING RES & DESIGN INS OF CHE IND CO LTD
- Filing Date
- 2023-10-16
- Publication Date
- 2026-07-14
Smart Images
Figure CN117168193B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of heat exchange technology, and in particular to a heat exchange system, method and equipment. Background Technology
[0002] With the rise and development of the semiconductor industry, the purity requirements for electron etching have become increasingly stringent, and purification methods mainly include adsorption and distillation. Due to the high purity requirements, the stability of the distillation process is also crucial, making it very important to provide a stable cold and hot heat exchange medium.
[0003] The heat transfer medium technology is mature and relatively easy to provide stably. However, for the distillation of substances with low boiling points such as nitrogen trifluoride and carbon monoxide, conventional heat exchange media such as Freon cannot support the process requirements. Liquid nitrogen is often used as the heat exchange medium, utilizing its latent heat of vaporization as a refrigerant. Heat exchange using liquid nitrogen as the distillation refrigerant is achieved through coils. At atmospheric pressure, liquid nitrogen has a boiling point of -196℃ and a critical pressure of -147℃; the boiling point varies with pressure. While coils can mitigate the effects of thermal expansion and contraction, the varying space occupied by the liquid nitrogen within the coil results in different heat exchange areas. Furthermore, the vaporized nitrogen cannot be discharged in real time, leading to pressure variations within the coil and consequently, different boiling points. This instability can result in low yields or, in severe cases, a batch of substandard products. Meanwhile, liquid nitrogen is generally stored at around 1.0 MPa in the tank. The pressure in the coil is unstable. During the process of uncontrolled and disorderly pressure reduction, some of the latent heat of vaporization is used for its own cooling, and the temperature of the vaporized nitrogen is also low, thus wasting some of the latent heat of vaporization of liquid nitrogen.
[0004] Reversible exothermic reactions typically have an optimal reaction temperature. For example, if the optimal temperature for a reversible exothermic reaction is 160℃, then using low-pressure hot water at around 150-155℃ to remove the heat of reaction, with the outlet being hot water at 165-170℃, keeps the reactor temperature within a range of 10-20℃. This results in a large deviation of the reaction's conversion rate and selectivity from the optimal reaction range, leading to a low yield. Summary of the Invention
[0005] The purpose of this invention is to provide a heat exchange system, method, and device to improve the heat exchange efficiency of the cold medium.
[0006] To achieve the above objectives, embodiments of the present invention provide the following solutions:
[0007] A heat exchange system, comprising:
[0008] Refrigerant storage tanks are used to store refrigerant at a preset pressure value;
[0009] A first pneumatic ball valve, wherein the first input terminal of the first pneumatic ball valve is connected to the output terminal of the refrigerant storage tank, is used for:
[0010] The pressure of the refrigerant is adjusted according to the first control command to obtain the refrigerant after pressure adjustment.
[0011] Based on the liquid level value and a first liquid level threshold, a liquid level difference value is obtained; the magnitude of the liquid level difference value and the first liquid level difference threshold value is determined; if the liquid level difference value is greater than or equal to the first liquid level difference threshold value, the opening degree of the first pneumatic ball valve is reduced and the liquid level value is continued to be acquired; if the liquid level difference value is less than the first liquid level difference threshold value, the opening degree of the first pneumatic ball valve is increased and the liquid level value is continued to be acquired.
[0012] A heat exchanger, wherein the first inlet of the heat exchanger is connected to the first output end of the first pneumatic ball valve, is used for heat exchange between the pressure-regulated cold medium and the hot material; the hot material is input from the second inlet of the heat exchanger, and the hot material after heat exchange is discharged from the second outlet of the heat exchanger;
[0013] A level gauge, wherein the high-pressure port of the level gauge is connected to the low point of the shell side of the heat exchanger, and the low-pressure port of the level gauge is connected to the high point of the shell side of the heat exchanger, for displaying the level value of the cooling medium inside the heat exchanger.
[0014] A pressure sensor, connected to the shell-side high point of the heat exchanger, is used to detect the internal pressure of the heat exchanger under different operating conditions, obtain the pressure value, and send the first control command; the different operating conditions specifically include: abnormal operating conditions, accident operating conditions, and normal operating conditions;
[0015] The discharge pipe module has its input end connected to the highest point of the shell side of the heat exchanger, and its output end connected to the refrigerant vaporization gas recovery module, for the following purposes:
[0016] Discharge the cooled medium after heat exchange;
[0017] Based on the internal pressure value of the heat exchanger and a first pressure threshold, a pressure difference is obtained; the magnitude of the pressure difference and the first pressure difference threshold is determined; if the pressure difference is greater than or equal to the first pressure difference threshold, the outlet opening of the discharge pipe module is increased and the internal pressure value of the heat exchanger is continued to be acquired; if the pressure difference is less than the first pressure difference threshold, the outlet opening of the discharge pipe module is decreased and the internal pressure value of the heat exchanger is continued to be acquired.
[0018] The refrigerant vaporization recovery module is connected to the input end of the refrigerant storage tank for the recycling of the refrigerant.
[0019] Optionally, the discharge pipe module includes:
[0020] There are N emission units, the input end of any of the emission units is connected to the shell-side high point of the heat exchanger, and is used to adjust the pressure of the cold medium after heat exchange; N is greater than or equal to 2.
[0021] Optionally, at least one of the N emission units includes:
[0022] The first discharge pipe has its inlet end connected to the highest point of the shell side of the heat exchanger, and is used to input the refrigerant after heat exchange.
[0023] A pneumatic throttle valve, the input end of which is connected to the output end of the first discharge pipe, is used to adjust the refrigerant after heat exchange by an equal percentage.
[0024] The second discharge pipe, whose input end is connected to the output end of the pneumatic throttle valve, is used to discharge the refrigerant after heat exchange.
[0025] Optionally, at least one of the N emission units includes:
[0026] The third discharge pipe, the input end of which is connected to the high point of the shell side of the heat exchanger, is used to input the refrigerant after heat exchange;
[0027] The second pneumatic ball valve, whose input end is connected to the output end of the third discharge pipe, is used to adjust the refrigerant after heat exchange by an equal percentage.
[0028] The fourth discharge pipe, the input end of which is connected to the output end of the second pneumatic ball valve, is used to discharge the refrigerant after heat exchange.
[0029] Optionally,
[0030] The pneumatic throttle valve is interlocked with the pressure sensor;
[0031] The second pneumatic ball valve is interlocked with the pressure sensor.
[0032] Optionally, the level gauge is interlocked with the first pneumatic ball valve.
[0033] To achieve the above objectives, embodiments of the present invention also provide the following solutions:
[0034] A heat exchange method, comprising:
[0035] Obtain the liquid level value and preset the first liquid level threshold;
[0036] Based on the liquid level value and the first liquid level threshold, a liquid level difference value is obtained; the magnitude of the liquid level difference value and the first liquid level difference threshold value is determined; if the liquid level difference value is greater than or equal to the first liquid level difference threshold value, the opening degree of the first pneumatic ball valve is reduced and the liquid level value is continued to be acquired; if the liquid level difference value is less than the first liquid level difference threshold value, the opening degree of the first pneumatic ball valve is increased and the liquid level value is continued to be acquired.
[0037] Obtain the internal pressure values of the heat exchanger under different operating conditions and preset the first pressure threshold;
[0038] Based on the internal pressure value of the heat exchanger and a first pressure threshold, a pressure difference is obtained; the magnitude of the pressure difference and the first pressure difference threshold is determined; if the pressure difference is greater than or equal to the first pressure difference threshold, the outlet opening of the discharge pipe module is increased and the internal pressure value of the heat exchanger is continued to be acquired; if the pressure difference is less than the first pressure difference threshold, the outlet opening of the discharge pipe module is decreased and the internal pressure value of the heat exchanger is continued to be acquired.
[0039] Optionally, the different operating conditions specifically include:
[0040] Abnormal operating conditions, accident operating conditions, and normal operating conditions.
[0041] An electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the heat exchange method.
[0042] A non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed, implements the heat exchange method described above.
[0043] In this embodiment of the invention, the internal pressure values of the heat exchanger under different operating conditions are obtained, and a first pressure threshold is preset; a pressure difference is obtained based on the internal pressure values of the heat exchanger and the first pressure threshold; the magnitude of the pressure difference and the first pressure difference threshold is determined; if the pressure difference is greater than or equal to the first pressure difference threshold, the outlet opening of the discharge pipe module is increased, and the internal pressure value of the heat exchanger is continued to be obtained; if the pressure difference is less than the first pressure difference threshold, the outlet opening of the discharge pipe module is decreased, and the internal pressure value of the heat exchanger is continued to be obtained. Utilizing the characteristic that the boiling point of the cold medium is different under different pressures, the temperature is controlled by controlling the pressure of the cold medium, and heat exchange is performed using the latent heat of vaporization of the cold medium, thereby improving the heat exchange efficiency of the cold medium. Attached Figure Description
[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0045] Figure 1 This is a schematic diagram of the heat exchange system provided in an embodiment of the present invention;
[0046] Figure 2 This is a schematic flowchart of the heat exchange method provided in an embodiment of the present invention;
[0047] Figure 3 This is a schematic diagram of liquid nitrogen as a refrigerant for heat exchange, provided in an embodiment of the present invention.
[0048] Figure 4 This is a schematic diagram of the shape of the heat exchange tubes using liquid nitrogen as the refrigerant, provided in an embodiment of the present invention.
[0049] Figure 5 This is a schematic diagram of a reversible exothermic reaction provided in an embodiment of the present invention.
[0050] Symbol explanation:
[0051] Refrigerant storage tank-1, first pneumatic ball valve-2, heat exchanger-3, level gauge-4, pressure sensor-5, discharge pipe module-6, refrigerant vaporization gas recovery module-7, first discharge pipe-8, pneumatic throttle valve-9, second discharge pipe-10, third discharge pipe-11, second pneumatic ball valve-12, fourth discharge pipe-13, refrigerant outlet regulating valve of heat exchanger-14, outlet regulating valve of heat exchanger-15. Detailed Implementation
[0052] 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.
[0053] The purpose of this invention is to provide a heat exchange system, method, and device to solve the problem of low heat exchange efficiency of existing cold mediums.
[0054] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0055] Figure 1 An exemplary structure of the heat exchange system described above is shown. The modules are described in detail below.
[0056] Refrigerant storage tank 1 is used to store refrigerant at a preset pressure value;
[0057] In one example, the preset pressure value can be 12 bar; the cooling medium can be liquid nitrogen.
[0058] The first input terminal of the first pneumatic ball valve 2 is connected to the output terminal of the refrigerant storage tank 1. The first pneumatic ball valve 2 is used for:
[0059] The pressure of the refrigerant is adjusted according to the first control command to obtain the refrigerant after pressure adjustment.
[0060] In one example, pressure sensor 5 determines whether to send a first control command based on the real-time measured pressure value. The first pneumatic ball valve 2 adjusts its opening according to the first control command, thereby regulating the pressure of the refrigerant.
[0061] Based on the liquid level value and a first liquid level threshold, a liquid level difference value is obtained; the magnitude of the liquid level difference value and the first liquid level difference threshold value is determined; if the liquid level difference value is greater than or equal to the first liquid level difference threshold value, the opening degree of the first pneumatic ball valve 2 is reduced and the liquid level value is continued to be acquired; if the liquid level difference value is less than the first liquid level difference threshold value, the opening degree of the first pneumatic ball valve 2 is increased and the liquid level value is continued to be acquired.
[0062] In one example, the level gauge 4 obtains the level difference based on the real-time measured level value and a first level threshold. The first level threshold can be, for example, 130 mm (the tube height of heat exchanger 3 is 100 mm, and the refrigerant needs to submerge the tubes by 30 mm), and the first level difference threshold can be, for example, 10 mm. When the level value is 140 mm, the level difference is 10 mm. Since the level difference is greater than or equal to the first level difference threshold, it indicates that the refrigerant level inside heat exchanger 3 is too high and needs to be reduced. At this point, the opening of the first pneumatic ball valve 2 can be reduced to decrease the inflow of refrigerant. Simultaneously, the outflow of refrigerant remains constant, causing the liquid level to decrease, and the level value continues to be acquired.
[0063] In another example, level gauge 4 obtains the level difference based on the real-time measured level value and a first level threshold. The first level threshold can be, for example, 130 mm (the tube height of heat exchanger 3 is 100 mm, and the refrigerant needs to submerge the tubes by 30 mm), and the first level difference threshold can be, for example, 10 mm. When the level value is 125 mm, the absolute value of the level difference is 5 mm, which is less than the first level difference threshold. This indicates that the refrigerant level inside heat exchanger 3 is too low and needs to be increased. In this case, the opening of the first pneumatic ball valve 2 can be increased to increase the inflow of refrigerant. Simultaneously, the outflow of refrigerant remains constant, causing the liquid level to rise, and the level value continues to be acquired.
[0064] The first inlet of the heat exchanger 3 is connected to the first output end of the first pneumatic ball valve 2. The heat exchanger 3 is used for heat exchange between the pressure-regulated cold medium and the hot material. The hot material is input from the second inlet of the heat exchanger 3, and the hot material after heat exchange is discharged from the second outlet of the heat exchanger 3.
[0065] In one example, heat exchanger 3 can specifically be a shell-and-tube heat exchanger 3; in the shell-and-tube heat exchanger 3, the space occupied by the tubes is 60%-70%, which provides a large space for the vaporization gas of the cold medium and greatly increases the adjustability.
[0066] The high-pressure port of the level gauge 4 is connected to the low point of the shell side of the heat exchanger 3, and the low-pressure port of the level gauge 4 is connected to the high point of the shell side of the heat exchanger 3. The level gauge 4 is used to display the level value of the cooling medium inside the heat exchanger 3.
[0067] In one example, the level gauge 4 is interlocked with the first pneumatic ball valve 2 to ensure that the tubes of the heat exchanger 3 are always submerged by the cold medium, thus ensuring that the heat exchange area remains unchanged.
[0068] Pressure sensor 5 is connected to the shell side high point of heat exchanger 3. Pressure sensor 5 is used to detect the internal pressure of heat exchanger 3 under different operating conditions, obtain the pressure value and send the first control command; the different operating conditions specifically include: abnormal operating conditions, accident operating conditions and normal operating conditions.
[0069] The input end of the discharge pipe module 6 is connected to the highest point of the shell side of the heat exchanger 3, and the output end of the discharge pipe module 6 is connected to the refrigerant vaporization gas recovery module 7. The discharge pipe module 6 is used for:
[0070] Discharge the cooled medium after heat exchange;
[0071] Based on the internal pressure value of the heat exchanger 3 and the first pressure threshold, a pressure difference is obtained; the magnitude of the pressure difference and the first pressure difference threshold is determined; if the pressure difference is greater than or equal to the first pressure difference threshold, the outlet opening of the discharge pipe module 6 is increased and the internal pressure value of the heat exchanger is continued to be obtained; if the pressure difference is less than the first pressure difference threshold, the outlet opening of the discharge pipe module 6 is decreased and the internal pressure value of the heat exchanger is continued to be obtained.
[0072] In one example, pressure sensor 5 obtains a pressure difference based on the real-time measured pressure value and a first pressure threshold. The first pressure threshold can be, for example, 12 bar, and the first pressure difference threshold can be, for example, 0.5 bar. When the stress value is 14 bar, the pressure difference is 2 bar. Since the pressure difference is greater than or equal to the first pressure difference threshold, it indicates that the pressure of the cold medium inside heat exchanger 3 is too high and needs to be reduced. At this point, the outlet opening of the discharge pipe module 6 can be increased to reduce the pressure of the cold medium. Simultaneously, the outflow rate of the cold medium remains constant, causing the pressure to decrease, and pressure values continue to be acquired.
[0073] In another example, pressure sensor 5 obtains a pressure difference based on the real-time measured pressure value and a first pressure threshold. The first pressure threshold can be, for example, 12 bar, and the first pressure difference threshold can be, for example, 0.5 bar. When the stress value is 11.8 bar, the pressure difference is 0.2 bar, which is less than the first pressure difference threshold. This indicates that the pressure of the cold medium inside heat exchanger 3 is too low and needs to be increased. At this point, the outlet opening of the discharge pipe module 6 can be reduced to increase the pressure of the cold medium. Simultaneously, the outflow rate of the cold medium remains constant, causing the pressure to rise, and pressure values continue to be acquired.
[0074] The refrigerant vaporization gas recovery module 7 is connected to the input end of the refrigerant storage tank 1, and the refrigerant vaporization gas recovery module 7 is used for the recycling of refrigerant.
[0075] The discharge pipe module 6 includes:
[0076] There are N discharge units, the input end of any of the discharge units is connected to the shell side high point of the heat exchanger 3, and the discharge units are used to adjust the pressure of the cold medium after heat exchange; N is greater than or equal to 2.
[0077] At least one of the N emission units includes:
[0078] The inlet end of the first discharge pipe 8 is connected to the shell side high point of the heat exchanger 3, and the first discharge pipe 8 is used to input the cold medium after heat exchange;
[0079] The input end of the pneumatic throttle valve 9 is connected to the output end of the first discharge pipe 8. The pneumatic throttle valve 9 is used to adjust the refrigerant after heat exchange by an equal percentage.
[0080] The input end of the second discharge pipe 10 is connected to the output end of the pneumatic throttle valve 9, and the second discharge pipe 10 is used to discharge the cold medium after heat exchange.
[0081] In other embodiments of the present invention, at least one of the N emission units includes:
[0082] The inlet of the third discharge pipe 11 is connected to the high point of the shell side of the heat exchanger 3, and the third discharge pipe 11 is used to input the cold medium after heat exchange.
[0083] The input end of the second pneumatic ball valve 12 is connected to the output end of the third discharge pipe 11. The second pneumatic ball valve 12 is used to adjust the refrigerant after heat exchange by an equal percentage.
[0084] The input end of the fourth discharge pipe 13 is connected to the output end of the second pneumatic ball valve 12, and the fourth discharge pipe 13 is used to discharge the cold medium after heat exchange.
[0085] In one example, the second discharge pipe 10 has a diameter such that when the valve is fully open, it can pass through 80% of the refrigerant vaporized gas; the third discharge pipe 11 has a diameter such that when the valve is fully open, it can pass through 70% of the refrigerant vaporized gas; another third discharge pipe 11 has a diameter such that when the valve is fully open, it can pass through 10% of the vaporized gas. The number of third discharge pipes 11 can be increased according to operating conditions. This greatly increases adjustability and minimizes the error in refrigerant temperature fluctuations around the target temperature.
[0086] The second discharge pipe 10 uses a proportional pneumatic throttle valve 9; the third discharge pipe 11 uses a switch valve.
[0087] The pneumatic throttle valve 9 is interlocked with the pressure sensor 5;
[0088] The second pneumatic ball valve 12 is interlocked with the pressure sensor 5.
[0089] The level gauge 4 is interlocked with the first pneumatic ball valve 2.
[0090] In summary, in this embodiment of the invention, the internal pressure values of the heat exchanger under different operating conditions are obtained and a first pressure threshold is preset; a pressure difference is obtained based on the internal pressure values of the heat exchanger and the first pressure threshold; the magnitude of the pressure difference and the first pressure difference threshold is determined; if the pressure difference is greater than or equal to the first pressure difference threshold, the outlet opening of the discharge pipe module is increased and the internal pressure value of the heat exchanger is continued to be obtained; if the pressure difference is less than the first pressure difference threshold, the outlet opening of the discharge pipe module is decreased and the internal pressure value of the heat exchanger is continued to be obtained. Utilizing the characteristic that the boiling point of the cold medium is different under different pressures, the temperature is controlled by controlling the pressure of the cold medium, and heat exchange is performed using the latent heat of vaporization of the cold medium, thereby improving the heat exchange efficiency of the cold medium.
[0091] By controlling the pressure of the refrigerant, the refrigerant is kept within a small temperature range, thereby making the heat exchange process more stable. In other embodiments of the invention, the heat exchange system is also used for reversible exothermic reactions, which can improve yield and selectivity, reduce environmental costs, increase resistance to runaway temperatures, increase safety, and convert the refrigerant into steam, improving energy grade and enabling energy recovery. In other embodiments of the invention, the heat exchange system is used for cryogenic distillation, which can increase the stability of the distillation column top, make the process more controllable, and stably control the amount of refrigerant used, thus saving refrigerant and preventing excessive consumption of heat energy in the reboiler.
[0092] To achieve the above objectives, embodiments of the present invention also provide the following solutions:
[0093] Please see Figure 2 A heat exchange method, comprising:
[0094] Obtain the liquid level value and preset the first liquid level threshold;
[0095] Based on the liquid level value and the first liquid level threshold, a liquid level difference value is obtained; the magnitude of the liquid level difference value and the first liquid level difference threshold value is determined; if the liquid level difference value is greater than or equal to the first liquid level difference threshold value, the opening degree of the first pneumatic ball valve is reduced and the liquid level value is continued to be acquired; if the liquid level difference value is less than the first liquid level difference threshold value, the opening degree of the first pneumatic ball valve is increased and the liquid level value is continued to be acquired.
[0096] Obtain the internal pressure values of the heat exchanger under different operating conditions and preset the first pressure threshold;
[0097] Based on the internal pressure value of the heat exchanger and a first pressure threshold, a pressure difference is obtained; the magnitude of the pressure difference and the first pressure difference threshold is determined; if the pressure difference is greater than or equal to the first pressure difference threshold, the outlet opening of the discharge pipe module is increased and the internal pressure value of the heat exchanger is continued to be acquired; if the pressure difference is less than the first pressure difference threshold, the outlet opening of the discharge pipe module is decreased and the internal pressure value of the heat exchanger is continued to be acquired.
[0098] The different operating conditions specifically include:
[0099] Abnormal operating conditions, accident operating conditions, and normal operating conditions.
[0100] In other embodiments of the present invention, when the level gauge 4 controls the first pneumatic ball valve 2 to maintain the liquid level 30mm above the submerged tube, the first pneumatic ball valve 2 is opened to replenish the cold medium. When the cold medium level is 100mm above the submerged tube level, the first pneumatic ball valve 2 is closed to stop replenishing the cold medium, and the liquid level is controlled at 30-100mm above the submerged tube.
[0101] During pneumatic operation, the pressure value of pressure sensor 5 is set to P. At this time, the opening of regulating valve 6 gradually increases. When the opening of pneumatic throttle valve 9 is 90%, the second pneumatic ball valve 12 connected to the third discharge pipe 11 (gas phase discharge pipe) is opened. When the refrigerant pressure is stable, the opening of pneumatic throttle valve 9 is adjusted to between 35% and 45%. Those skilled in the art can flexibly design the value of P, such as 11.5, 12, 12.5, etc., which will not be elaborated here.
[0102] In case of abnormal operating conditions (reduced heating capacity), when the opening of the pneumatic throttle valve 9 drops below 10%, the second pneumatic ball valve 12 located at the third discharge pipe 11 is closed.
[0103] In abnormal operating conditions (increased heating), when the opening of the pneumatic throttle valve 9 increases to 55%, the second pneumatic ball valve 12, located on the third discharge pipe 11, opens. When the opening of the pneumatic throttle valve 9 decreases to below 25%, the second pneumatic ball valve 12, located on the third discharge pipe 11, closes. When the second pneumatic ball valve 12, located on the third discharge pipe 11, is open, the control sequence for abnormal operating conditions (increased heating) is effective; otherwise, it is ineffective.
[0104] The accident condition is when the pneumatic throttle valve 9, the second pneumatic ball valve 12 where the third discharge pipe 11 is located, and the second pneumatic ball valve 12 where another third discharge pipe 11 is located are fully open.
[0105] When the heat exchanger 3 overheats, the valves of the cooling medium output regulating valve 14, the first pneumatic ball valve 2, and the discharge pipe module 6 of the heat exchanger 3 can be fully opened.
[0106] The number of split-range control and emission units is selected according to the actual working conditions, which increases safety while minimizing the error of the refrigerant temperature within the target temperature range.
[0107] Example 1:
[0108] Carbon monoxide is distilled at 2.2 MPa, where its boiling point is -152°C. Liquid nitrogen at -167°C is used as the cooling medium in storage tank 1, at which temperature the saturated vapor pressure is 12 bar. During stable distillation, the load on storage tank 1 is constant, resulting in a constant amount of vaporized cooling medium. By controlling the discharge rate, the pressure of the vaporized cooling medium can be controlled, thereby stabilizing the liquid nitrogen temperature.
[0109] like Figure 3 As shown, when the heat exchange system is started, the first pneumatic ball valve 2 for liquid nitrogen is opened, the pressure sensor 5 is set to 12 bar, and the level gauge 4 is set to submerge the tubes by 50 mm. Distillation heating is then started. When the pneumatic throttle valve 9 is open to 90%, the second pneumatic ball valve 12, where the third discharge pipe 11 is located, is opened.
[0110] Because the heat load is constant under normal operating conditions, the opening degree of the pneumatic throttle valve 9 is between 35% and 45%.
[0111] The heat exchange system is shut down normally. The first pneumatic ball valve 2 for liquid nitrogen is closed, and the pressure is controlled to be above 10 bar for orderly discharge.
[0112] like Figure 4 As shown, the tube-and-shell shape of heat exchanger 3 when liquid nitrogen is the cooling medium can avoid the forces exerted on the material by thermal expansion and contraction.
[0113] Example 2:
[0114] Vinyl acetate was synthesized via a gas-phase ethylene process at 160℃, where the saturated vapor pressure of water was 530 kPa. Low-pressure hot water at 159℃ was used as the cooling medium for heat exchange. The shell-side pressure of the heat exchanger was controlled at 530 kPa. Under normal operating conditions, with a constant heat of reaction, the amount of vaporized gas from the cooling medium was constant. By controlling the discharge rate, the hot water pressure could be controlled, thereby stabilizing the reaction temperature.
[0115] like Figure 5 As shown, when the heat exchange system is started, the first pneumatic ball valve 2 for low-pressure hot water is opened, the pressure sensor 5 is set to 530 kPa, and the level gauge 4 is set to submerge the tubes by 50 mm. Reactants are introduced. When the pneumatic throttle valve 9 is 90% open, the pneumatic throttle valve 9 located on the first discharge pipe 8 is opened.
[0116] Because the heat load is constant under normal operating conditions, the opening degree of the pneumatic throttle valve 9 is between 35% and 45%.
[0117] When the heat exchanger 3 overheats, the valves of the cooling medium output regulating valve 14, the first pneumatic ball valve 2, and the discharge pipe module 6 of the heat exchanger 3 can be fully opened. A large amount of steam can carry away a large amount of heat, which improves the ability to resist risks and greatly increases safety.
[0118] When the heat exchange system is shut down normally, close the first pneumatic ball valve 2 for low-pressure hot water, release the pressure to atmospheric pressure, and discharge 100℃ hot water in an orderly manner.
[0119] Furthermore, the present invention also provides an electronic device, which may include: a processor, a communication interface, a memory, and a communication bus. The processor, communication interface, and memory communicate with each other via the communication bus. The processor can call a computer program stored in the memory to execute the heat exchange method described above.
[0120] Furthermore, when the computer program in the aforementioned memory is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory, random access memory, magnetic disks, or optical disks.
[0121] Furthermore, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed, implements the heat exchange method described above.
[0122] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.
[0123] This document uses specific examples to illustrate the principles and implementation methods of the embodiments of the present invention. The descriptions of the embodiments above are only for the purpose of helping to understand the methods and core ideas of the embodiments of the present invention. At the same time, for those skilled in the art, there will be changes in specific implementation methods and application scope based on the ideas of the embodiments of the present invention. In summary, the content of this specification should not be construed as a limitation on the embodiments of the present invention.
Claims
1. A heat exchange system, characterized in that, include: Refrigerant storage tanks are used to store refrigerant at a preset pressure value; A first pneumatic ball valve, wherein the first input terminal of the first pneumatic ball valve is connected to the output terminal of the refrigerant storage tank, is used for: The pressure of the refrigerant is adjusted according to the first control command to obtain the refrigerant after pressure adjustment. The liquid level difference is obtained based on the liquid level value and a first liquid level threshold. The magnitude of the liquid level difference and the first liquid level difference threshold are determined. If the liquid level difference is greater than or equal to the first liquid level difference threshold, the opening of the first pneumatic ball valve is reduced and the liquid level value is continued to be acquired. If the liquid level difference is less than the first liquid level difference threshold, the opening of the first pneumatic ball valve is increased and the liquid level value is continued to be acquired. The heat exchanger tubes are always kept submerged by the cold medium, ensuring that the heat exchange area remains unchanged. A heat exchanger, wherein the first inlet of the heat exchanger is connected to the first output end of the first pneumatic ball valve, and is used for heat exchange between the pressure-regulated cold medium and the hot material; the hot material is input from the second inlet of the heat exchanger, and the hot material after heat exchange is discharged from the second outlet of the heat exchanger; A level gauge, wherein the high-pressure port of the level gauge is connected to the low point of the shell side of the heat exchanger, and the low-pressure port of the level gauge is connected to the high point of the shell side of the heat exchanger, for displaying the level value of the cooling medium inside the heat exchanger. A pressure sensor, connected to the shell-side high point of the heat exchanger, is used to detect the internal pressure of the heat exchanger under different operating conditions, obtain the pressure value, and send the first control command; the different operating conditions specifically include: abnormal operating conditions, accident operating conditions, and normal operating conditions; The discharge pipe module has its input end connected to the highest point of the shell side of the heat exchanger, and its output end connected to the refrigerant vaporization gas recovery module, for the following purposes: Discharge the cooled medium after heat exchange; A pressure difference is obtained based on the internal pressure value of the heat exchanger and a first pressure threshold. The magnitude of the pressure difference relative to the first pressure difference threshold is determined. If the pressure difference is greater than or equal to the first pressure difference threshold, the outlet opening of the discharge pipe module is increased, and the internal pressure value of the heat exchanger is continued to be acquired. If the pressure difference is less than the first pressure difference threshold, the outlet opening of the discharge pipe module is decreased, and the internal pressure value of the heat exchanger is continued to be acquired. The discharge pipe module includes: N discharge units, the input end of any discharge unit being connected to the shell-side high point of the heat exchanger, used to adjust the pressure of the refrigerant after heat exchange; N is greater than or equal to 2; at least one of the N discharge units includes: a first discharge pipe, the input end of which is connected to the shell-side high point of the heat exchanger, used to input the refrigerant after heat exchange; and a pneumatic throttle valve, the input end of which is connected to the output end of the first discharge pipe. The system comprises: a first discharge pipe for adjusting the refrigerant after heat exchange at a percentage; a second discharge pipe, the input of which is connected to the output of the pneumatic throttle valve, for discharging the refrigerant after heat exchange; and at least one of the N discharge units including: a third discharge pipe, the input of which is connected to the shell-side high point of the heat exchanger, for inputting the refrigerant after heat exchange; a second pneumatic ball valve, the input of which is connected to the output of the third discharge pipe, for adjusting the refrigerant after heat exchange at a percentage; and a fourth discharge pipe, the input of which is connected to the output of the second pneumatic ball valve, for discharging the refrigerant after heat exchange; the pneumatic throttle valve is interlocked with the pressure sensor; and the second pneumatic ball valve is interlocked with the pressure sensor. By controlling the refrigerant pressure, the refrigerant is kept within a small temperature difference range, thereby making the heat exchange process more stable. The refrigerant vaporization recovery module is connected to the input end of the refrigerant storage tank for the recycling of the refrigerant.
2. The heat exchange system according to claim 1, characterized in that, The level gauge is interlocked with the first pneumatic ball valve.
3. A heat exchange method, characterized in that, The heat exchange method is applied to the heat exchange system according to any one of claims 1-2, and the heat exchange method includes: Obtain the liquid level value and preset the first liquid level threshold; Based on the liquid level value and the first liquid level threshold, a liquid level difference value is obtained; the magnitude of the liquid level difference value and the first liquid level difference threshold value is determined; if the liquid level difference value is greater than or equal to the first liquid level difference threshold value, the opening degree of the first pneumatic ball valve is reduced and the liquid level value is continued to be acquired; if the liquid level difference value is less than the first liquid level difference threshold value, the opening degree of the first pneumatic ball valve is increased and the liquid level value is continued to be acquired; the heat exchanger tubes are always kept submerged by the cold medium to ensure that the heat exchange area remains unchanged; Obtain the internal pressure values of the heat exchanger under different operating conditions and preset the first pressure threshold; A pressure difference is obtained based on the internal pressure value of the heat exchanger and a first pressure threshold. The magnitude of the pressure difference relative to the first pressure difference threshold is determined. If the pressure difference is greater than or equal to the first pressure difference threshold, the outlet opening of the discharge pipe module is increased, and the internal pressure value of the heat exchanger is continued to be acquired. If the pressure difference is less than the first pressure difference threshold, the outlet opening of the discharge pipe module is decreased, and the internal pressure value of the heat exchanger is continued to be acquired. The discharge pipe module includes: N discharge units, the input end of any discharge unit being connected to the shell-side high point of the heat exchanger, used to adjust the pressure of the refrigerant after heat exchange; N is greater than or equal to 2; at least one of the N discharge units includes: a first discharge pipe, the input end of which is connected to the shell-side high point of the heat exchanger, used to input the refrigerant after heat exchange; and a pneumatic throttle valve, the input end of which is connected to the output end of the first discharge pipe. The system comprises: a first discharge pipe for adjusting the refrigerant after heat exchange at a percentage; a second discharge pipe, the input of which is connected to the output of the pneumatic throttle valve, for discharging the refrigerant after heat exchange; and at least one of the N discharge units including: a third discharge pipe, the input of which is connected to the shell-side high point of the heat exchanger, for inputting the refrigerant after heat exchange; a second pneumatic ball valve, the input of which is connected to the output of the third discharge pipe, for adjusting the refrigerant after heat exchange at a percentage; and a fourth discharge pipe, the input of which is connected to the output of the second pneumatic ball valve, for discharging the refrigerant after heat exchange; the pneumatic throttle valve is interlocked with the pressure sensor; and the second pneumatic ball valve is interlocked with the pressure sensor. By controlling the refrigerant pressure, the refrigerant is kept within a small temperature difference range, thereby making the heat exchange process more stable.
4. The heat exchange method according to claim 3, characterized in that, The different operating conditions specifically include: Abnormal operating conditions, accident operating conditions, and normal operating conditions.
5. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the heat exchange method as described in claim 3.
6. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed, it implements the heat exchange method as described in claim 3.