A frost-preventing heat exchanger group and a control method

Abstract

The application discloses a heat exchanger group capable of preventing frost blocking, which comprises a heat exchanger mechanism, a lift valve group mechanism and an electrical control system, the heat exchanger mechanism is connected with the lift valve group mechanism through a first channel and a second channel, the lower end of the heat exchanger mechanism is respectively connected with a first heat exchange pipeline and a second heat exchange pipeline, a water supply control device is arranged on the first heat exchange pipeline, a cylinder control device is arranged on the lift valve group mechanism, the electrical control system is connected with the water supply control device and the cylinder control device respectively, the heat exchanger mechanism comprises a heat exchange box body, a first heat exchanger, a second heat exchanger and a demister are arranged in the heat exchange box body, the demister is arranged on the right side of the first heat exchanger, and the second heat exchanger is arranged on the right side of the demister, so that the pretreatment system for removing water from a liquid nitrogen condensing system is safer and more reliable to operate, the number of valves in the system is reduced, and the system process is simple and reliable.

Description

Technical Field

[0001] This invention relates to the field of VOCs process exhaust gas purification technology, and in particular to a heat exchanger assembly and control method for preventing frost blockage. Background Technology

[0002] When using liquid nitrogen condensation to purify high-concentration VOCs process tail gas, this gas typically contains a high moisture content. Before entering the liquid nitrogen condensation system, the high-concentration VOCs process tail gas usually needs to be cooled to below zero degrees Celsius to remove the moisture. A common practice is to use sub-zero temperature chilled brine in a cooling heat exchanger to cool the high-concentration VOCs process tail gas. In this case, the moisture in the high-concentration VOCs process tail gas on the hot side of the cooling heat exchanger may cause ice blockage due to the chilled water temperature being below 0°C. When ice blockage occurs on the hot side, it will affect the normal and stable operation of the pre-cooling system, preventing continuous and stable operation. To address this, a common practice is to use a pre-cooling heat exchanger system with one operating and one standby unit to ensure continuous and stable system operation. When using a dual heat exchanger system with one operating and one standby unit, defrosting of the heat exchanger experiencing ice blockage is usually performed using electric heating. However, this method has the following problems:

[0003] 1. Electric heating comes into direct contact with high-concentration VOCs in the process exhaust gas, posing a safety hazard;

[0004] 2. During the defrosting process using electric heating, the hot side requires a purge airflow to ensure the effectiveness and speed of defrosting. Therefore, additional purge lines and their control systems are needed. This results in a complex system and high cost.

[0005] 3. The purging air needs to be reintroduced into the inlet of another operating heat exchanger, which increases the system's processing air volume and load;

[0006] 4. Due to the increased amount of purging gas, separate shut-off valves are required at the outlets of both heat exchangers. This increases the cost and control complexity of the main pipeline.

[0007] 5. Using electric heating to heat the heat exchanger increases the consumption of chilled water, thus increasing the system's operating costs. Summary of the Invention

[0008] The purpose of this invention is to provide a heat exchanger assembly and control method to prevent frost blockage, so as to solve the problems mentioned in the background art. By adopting the process method and control of this invention, the pretreatment system for dewatering liquid nitrogen condensation system is made safer and more reliable, the number of valves in the system configuration is reduced, the system process is simple and reliable, the investment cost is significantly reduced, and the operating cost is also reduced because electric heating for defrosting is no longer required.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] A heat exchanger assembly for preventing frost blockage includes a heat exchanger mechanism, a lift valve assembly mechanism, and an electrical control system. The heat exchanger mechanism and the lift valve assembly mechanism are connected via a first channel and a second channel. The lower end of the heat exchanger mechanism is connected to a first heat exchange pipe and a second heat exchange pipe, respectively. A water supply control device is installed on the first heat exchange pipe. A cylinder control device is installed on the lift valve assembly mechanism. The electrical control system is connected to both the water supply control device and the cylinder control device. The heat exchanger mechanism includes a heat exchange chamber, within which a first heat exchanger, a second heat exchanger, and a demister are installed. A demister is located to the right of the first heat exchanger, and a second heat exchanger is located to the right of the demister. The lift valve assembly mechanism includes an inner valve mechanism, a first exhaust gas pipe, and a second exhaust gas pipe. One end of the inner valve mechanism is connected to the first exhaust gas pipe, and the other end is connected to the second exhaust gas pipe. The lift valve assembly mechanism is connected to a first linear cylinder and a second linear cylinder of the cylinder control device.

[0011] The inner valve mechanism includes an inner valve housing and multiple air chambers. The inner valve housing is provided with multiple air chambers, including a first air chamber, a second air chamber, and a third air chamber. The second air chamber is located at the lower end of the first air chamber, and the third air chamber is located at the lower end of the second air chamber. The first air chamber is connected to the second air chamber through a first air hole and a fifth air hole, and the second air chamber is connected to the third air chamber through a fourth air hole and a sixth air hole.

[0012] The first air chamber is provided with a first air hole, which divides the first air chamber into two spaces. The second air chamber includes a left chamber and a right chamber, which are connected by a locking valve. The locking valve is fixed to the inner valve box. The third air chamber is provided with a second air hole, which divides the third air chamber into two spaces.

[0013] The inner valve box is connected to the first air chamber, the second air chamber and the third air chamber by a first linear cylinder and a second linear cylinder. The first linear cylinder is provided with a first valve plate and the second linear cylinder is provided with a second valve plate. The first valve plate controls the third air port and the fourth air port, and the second valve plate controls the fifth air port and the sixth air port.

[0014] The left cavity is connected to the first exhaust pipe, and the right cavity is connected to the second exhaust pipe.

[0015] The water supply control device includes a first water supply valve and a second water supply valve. The first water supply valve and the second water supply valve are respectively installed on the first heat exchange pipe. The first water supply valve is connected to the first heat exchanger, and the second water supply valve is connected to the second heat exchanger. The second heat exchange pipe is connected to the first heat exchanger and the second heat exchanger respectively.

[0016] Differential pressure monitoring instruments are respectively installed on the first exhaust gas pipe and the second exhaust gas pipe. The differential pressure information of the differential pressure monitoring instruments is transmitted to the electrical control system. Through the feedback of the differential pressure information, the electrical control system controls the water supply control device and the cylinder control device.

[0017] The demister is equipped with a drain valve at its lower end. The demister includes a demister housing, which is located within a heat exchanger mechanism. The demister housing contains multiple layers of filter grids, and each of the multiple filter grids is equipped with a bead condensation linkage device. The number of layers in the multiple filter grids is greater than 10.

[0018] The bead-coating linkage device includes a linkage plate, on which an elastic tension member is provided at its lower end. The elastic tension member is connected between the linkage plate and the filter grid plate. The linkage plate is inclinedly disposed on the filter grid plate and moves on the filter grid plate through a through shaft. A bead-coating ball is disposed on the filter grid plate at the upper end of the linkage plate. The diameter of the bead-coating ball is larger than the distance between the upper end of the linkage plate and the filter grid plate.

[0019] A control method for preventing frost blockage in a heat exchanger assembly includes the following steps:

[0020] S1: High-concentration VOCs process tail gas enters the lifting valve group mechanism from the first tail gas pipeline. The first linear cylinder of the electrical control system pushes the first valve plate to close the fourth air hole and open the third air hole. The second linear cylinder pushes the second valve plate to close the fifth air hole and open the sixth air hole. The high-concentration VOCs process tail gas enters the heat exchanger mechanism through the third air hole and the first air hole in sequence, and enters the heat exchanger mechanism through the first channel. In the heat exchanger mechanism, the high-concentration VOCs process tail gas passes through the second heat exchanger, the demister and the first heat exchanger in sequence.

[0021] S2: When the high-concentration VOCs process tail gas passes through the second heat exchanger, the second heat exchanger uses the relatively high temperature of the high-concentration VOCs process tail gas to defrost the heat exchanger. At the same time, the high-concentration VOCs process tail gas is also cooled down for the first time. After the high-concentration VOCs process tail gas is cooled down for the first time, it passes through a demister to remove the liquid droplets from the defrosting process, and then enters the first heat exchanger of the next stage for further cooling.

[0022] S3: At this time, the first water supply valve is open, the first heat exchanger provides a cold source, and the high-concentration VOCs process tail gas is further cooled to 0°C or below in the first heat exchanger. The water in it is removed, and the removed water forms condensate or freezes in the first heat exchanger. The high-concentration VOCs process tail gas cooled to below 0°C re-enters the lift valve group mechanism through the second channel, passes through the second air hole and the sixth air hole in sequence, and is then discharged from the system through pipe 2, thereby achieving the purpose of removing water and defrosting the system at the same time.

[0023] S4: As the system operates consistently, the frost / ice in the first heat exchanger will gradually increase, and the pressure drop of the entire system will gradually increase. The differential pressure detection instruments installed in the first and second tail gas pipelines of this device monitor the pressure drop of the entire system through the electrical control system.

[0024] S5: When the pressure drop reaches the set value, the electrical control system opens the second water supply valve and closes the first water supply valve. At the same time, the first linear cylinder is lifted to retract the valve rod, which drives the first valve plate to open the fourth air hole and close the third air hole. The second linear cylinder pushes the second valve plate to open the fifth air hole and close the sixth air hole.

[0025] S6: During system step S5, the high-concentration VOCs process tail gas enters the lift valve assembly through pipe 1 and then enters the heat exchanger assembly via the fourth vent, the second vent, and the second channel. Inside the heat exchanger assembly, the high-concentration VOCs process tail gas uses its relatively high temperature to heat and defrost the first heat exchanger. The high-concentration VOCs process tail gas is cooled for the first time, and then passes through a demister to remove the droplets formed after defrosting or cooling before entering the second heat exchanger for further cooling. Inside the second heat exchanger, the high-concentration VOCs process tail gas is further cooled to below 0°C, and the moisture in it is further condensed and precipitated, or even solidified into frost / ice. After the moisture is removed, it enters the lift valve assembly through the first channel, and then exits the system through the fifth vent and the second tail gas pipe in sequence, thereby achieving the purpose of removing moisture while defrosting the system.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] By employing the process and control methods of this invention, the pretreatment system for dehydration in liquid nitrogen condensation systems becomes safer and more reliable. The system requires fewer valves, resulting in a simpler and more reliable process. Investment costs are significantly reduced, and operating costs are also lowered because defrosting with electric heating is no longer required. Its specific advantages are reflected in the following five aspects:

[0028] 1. Since electric heating is no longer needed, the safety hazards associated with it are completely eliminated;

[0029] 2. The electric heating defrosting system requires four fewer valves, significantly reducing system complexity. This lowers investment costs and improves operational reliability.

[0030] 3. Since no additional purge air is needed during defrosting, there is no need to process the purge air, thus reducing the overall operating load of the system;

[0031] 4. Compared to electrically heated defrosting systems, chilled water consumption is also reduced. Furthermore, since defrosting of the heat exchanger utilizes the heat from the high-concentration VOCs process exhaust gas itself, the consumption of low-temperature chilled water is further reduced, resulting in correspondingly lower system operating costs. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall structure of the heat exchanger assembly for preventing frost blockage according to the present invention.

[0033] Figure 2 This is a schematic diagram illustrating the structural principle of the lifting valve assembly mechanism of the present invention.

[0034] Figure 3 This is a schematic diagram illustrating the structural principle of the demister of the present invention.

[0035] Figure 4 This is a schematic diagram of the structural principle of the bead-coating linkage device of the present invention.

[0036] Reference numerals: 1. First exhaust gas pipe; 2. Second exhaust gas pipe; 3. Lifting valve assembly; 4. First linear cylinder; 5. Second linear cylinder; 6. First channel; 7. Second channel; 8. Heat exchanger mechanism; 9. Electrical control system; 10. First heat exchange pipe; 11. First water supply valve; 12. Second water supply valve; 13. First heat exchanger; 14. Second heat exchanger; 15. Demister; 16. Drain valve; 17. Differential pressure monitoring instrument; 18. Internal valve mechanism; 19. Multi-layer gas chamber; 20. First gas... 21. Second air chamber, 22. Third air chamber, 23. Left chamber, 24. Right chamber, 25. Inner valve box, 26. Second heat exchange pipe, 27. Demister box, 28. Filter grid, 29. Condensation linkage device, 30. Linkage plate, 31. Elastic pull member, 32. Through shaft, 33. Condensation ball, 3-1. First air hole, 3-2. Second air hole, 3-3. Third air hole, 3-4. Fourth air hole, 3-5. Fifth air hole, 3-6. Sixth air hole, 4-1. First valve plate, 5-1. Second valve plate. Detailed Implementation

[0037] The following description, in conjunction with the accompanying drawings, provides a detailed account of specific embodiments of the present invention.

[0038] Example 1:

[0039] A heat exchanger assembly for preventing frost blockage includes a heat exchanger mechanism 8, a lift valve assembly mechanism 3, and an electrical control system 9. The heat exchanger mechanism 8 is connected to the lift valve assembly mechanism 3 via a first channel 6 and a second channel 7. A first heat exchange pipe 10 and a second heat exchange pipe 11 are respectively connected to the lower end of the heat exchanger mechanism 8. A water supply control device is installed on the first heat exchange pipe 10, and a cylinder control device is installed on the lift valve assembly mechanism 3. The electrical control system 9 is connected to both the water supply control device and the cylinder control device. The heat exchanger mechanism 8 includes... The device includes a heat exchange chamber, which houses a first heat exchanger 13, a second heat exchanger 14, and a demister 15. The demister 15 is located to the right of the first heat exchanger 13, and the second heat exchanger 14 is located to the right of the demister 15. The lifting valve assembly 3 includes an inner valve mechanism, a first exhaust gas pipe 1, and a second exhaust gas pipe 2. One end of the inner valve mechanism is connected to the first exhaust gas pipe 1, and the other end is connected to the second exhaust gas pipe 2. The lifting valve assembly 3 is connected to a first linear cylinder 4 and a second linear cylinder 5 of a cylinder control device.

[0040] The inner valve mechanism 18 includes an inner valve housing 25 and multiple air chambers. The inner valve housing 25 is provided with multiple air chambers, including a first air chamber 20, a second air chamber 21 and a third air chamber 22. The second air chamber 21 is provided at the lower end of the first air chamber 20, and the third air chamber 22 is provided at the lower end of the second air chamber 21. The first air chamber 20 is connected to the second air chamber 21 through a first air hole 3-1 and a fifth air hole 3-5, and the second air chamber 21 is connected to the third air chamber 22 through a fourth air hole 3-4 and a sixth air hole 3-6.

[0041] The first air chamber 20 is provided with a first air hole 3-1, which divides the first air chamber 20 into two spaces. The second air chamber 21 includes a left chamber 23 and a right chamber 24. The left chamber 23 and the right chamber 24 are connected by a locking valve, which is fixed to the inner valve box 25. The third air chamber 22 is provided with a second air hole 3-2, which divides the third air chamber 22 into two spaces.

[0042] The inner valve housing 25 is connected to the first air chamber 20, the second air chamber 21 and the third air chamber 22 by the first linear cylinder 4 and the second linear cylinder 5. The first linear cylinder 4 is provided with a first valve plate 4-1 and the second linear cylinder 5 is provided with a second valve plate 5-1. The first valve plate 4-1 controls the third air hole 3-3 and the fourth air hole 3-4, and the second valve plate 5-1 controls the fifth air hole 3-5 and the sixth air hole 3-6.

[0043] The left cavity 23 is connected to the first exhaust pipe 1, and the right cavity 24 is connected to the second exhaust pipe 2.

[0044] The water supply control device includes a first water supply valve 11 and a second water supply valve 12. The first water supply valve 11 and the second water supply valve 12 are respectively installed on the first heat exchange pipe 10. The first water supply valve 11 is connected to the first heat exchanger 13, and the second water supply valve 12 is connected to the second heat exchanger 14. The second heat exchange pipe 26 is connected to the first heat exchanger 13 and the second heat exchanger 14 respectively.

[0045] Differential pressure monitoring instruments 17 are respectively installed on the first exhaust gas pipe 1 and the second exhaust gas pipe 2. The differential pressure information of the differential pressure monitoring instruments 17 is transmitted to the electrical control system 9. Through the feedback of the differential pressure information, the electrical control system 9 controls the water supply control device and the cylinder control device.

[0046] The demister 15 is provided with a drain valve 16 at its lower end. The demister 15 includes a demister housing 27, which is located inside the heat exchanger mechanism 8. The demister housing 27 is provided with multiple layers of filter grids 28, and the multiple layers of filter grids 28 are provided with a bead condensation linkage device 29. The number of layers of the multiple layers of filter grids 28 is greater than 10.

[0047] The bead-coating linkage device 29 includes a linkage plate 30, on which an elastic tension member 31 is provided at the lower end. The elastic tension member 31 is connected between the linkage plate 30 and the filter grid plate. The linkage plate 30 is inclinedly disposed on the filter grid plate. The linkage plate 30 moves on the filter grid plate through a through shaft 32. A bead-coating ball 33 is disposed on the filter grid plate at the upper end of the linkage plate 30. The diameter of the bead-coating ball 33 is larger than the distance between the upper end of the linkage plate 30 and the filter grid plate.

[0048] A control method for preventing frost blockage in a heat exchanger assembly includes the following steps:

[0049] S1: High-concentration VOCs process tail gas enters the lifting valve group mechanism 3 from the first tail gas pipe 1. The first linear cylinder 4 of the electrical control system 9 pushes the first valve plate 4-1 to close the fourth air hole 3-4 and open the third air hole 3-3. The second linear cylinder 5 pushes the second valve plate 5-1 to close the fifth air hole 3-5 and open the sixth air hole 3-6. The high-concentration VOCs process tail gas enters the heat exchanger mechanism 8 through the first channel 6 via the third air hole 3-3 and the first air hole 3-1 in sequence. In the heat exchanger mechanism 8, the high-concentration VOCs process tail gas passes through the second heat exchanger 14, the demister 15 and the first heat exchanger 13 in sequence.

[0050] S2: When the high-concentration VOCs process tail gas passes through the second heat exchanger 14, the second heat exchanger 14 uses the relatively high temperature of the high-concentration VOCs process tail gas to defrost the heat exchanger. At the same time, the high-concentration VOCs process tail gas is also cooled down for the first time. After the high-concentration VOCs process tail gas is cooled down for the first time, it passes through the demister 15 to remove the liquid droplets during defrosting, and then enters the next stage first heat exchanger 13 for further cooling.

[0051] S3: At this time, the first water supply valve is open, and the first heat exchanger 13 provides a cold source. The high-concentration VOCs process tail gas is further cooled to 0°C or below in the first heat exchanger 13, and the water in it is removed. The removed water forms condensate or freezes in the first heat exchanger 13. The high-concentration VOCs process tail gas cooled to below 0°C re-enters the lifting valve group mechanism 3 through the second channel 7, passes through the second air hole 3-2 and the sixth air hole 3-6 in sequence, and is discharged from the system through the second tail gas pipe 2, thereby achieving the purpose of removing water and defrosting the system at the same time.

[0052] S4: As the system operates consistently, the frost / ice in the first heat exchanger 13 will gradually increase, and the pressure drop of the entire system will gradually increase. The differential pressure detection instrument 17 installed in the first tail gas pipeline 1 and the second tail gas pipeline 2 of this device monitors the pressure drop of the entire system through the electrical control system 9.

[0053] S5: When the pressure drop reaches the set value, the electrical control system 9 opens the second water supply valve 12 and closes the first water supply valve 11. At the same time, the first linear cylinder 4 is lifted and the valve rod is retracted to drive the first valve plate 4-1 to open the fourth air hole 3-4 and close the third air hole 3-3. The second linear cylinder 5 pushes the second valve plate 5-1 to open the fifth air hole 3-5 and close the sixth air hole 3-6.

[0054] S6: During system step S5, the high-concentration VOCs process tail gas enters the lift valve assembly through pipe 1 and then enters the heat exchanger assembly 8 through the fourth vent 3-4, the second vent 3-2, and the second channel 7. In the heat exchanger assembly 8, the high-concentration VOCs process tail gas uses its relatively high temperature to heat and defrost the first heat exchanger 13. The high-concentration VOCs process tail gas is cooled for the first time, and then passes through the demister 15 to remove the droplets formed after defrosting or cooling before entering the second heat exchanger 14 for further cooling. In the second heat exchanger 14, the high-concentration VOCs process tail gas is further cooled to below 0°C, and the water in it is further condensed and precipitated, or even solidified into frost / ice. After the water is removed, it enters the lift valve assembly 3 through the first channel, and then passes through the fifth vent 3-5 and the second tail gas pipe 2 in sequence to be discharged from the system, thereby achieving the purpose of removing water while defrosting the system.

[0055] Example 2:

[0056] Heat exchanger group 8 includes heat exchangers 13 and 14, and a demister 15. These three components are arranged in series within a housing channel. Alternatively, they can be connected in series via pipes. Their inlets and outlets are connected to channels 6 and 7, respectively. Pipe 10 is the chilled water supply pipe for the two heat exchangers, with supply valves installed on its branch pipes. Pipe 1 is the chilled water return pipe. The demister is located between the two heat exchangers and is equipped with a drain valve 16.

[0057] The lift valve assembly 3 comprises two linear cylinders 4 and 5. The cylinder shafts are connected to valve plates 4-1 and 5-1, respectively. By moving the cylinders, the valve plates seal or open the vent holes 3-3 / 3-4 and 3-5 / 3-6, respectively. In this way, high-concentration VOCs process exhaust gas entering from pipe 1 can flow in two directions. First: It enters the heat exchanger assembly through vent hole 3-3 and pipe 6, then enters the lift valve assembly through pipe 7. Within the lift valve assembly, the high-concentration VOCs process exhaust gas passes through vent hole 3-6 and reaches the discharge system through pipe 2. Second: It enters the heat exchanger assembly through vent hole 3-4 and pipe 7, then enters the lift valve assembly through pipe 6. Within the lift valve assembly, the high-concentration VOCs process exhaust gas passes through vent hole 3-5 and reaches the discharge system through pipe 2.

[0058] A differential pressure monitoring instrument 17 is installed between pipe 1 and pipe 2. This instrument is used to monitor the inlet and outlet pressure drop of the high-concentration VOCs process exhaust gas channel of the entire system in real time.

[0059] The specific operation process of this system is as follows:

[0060] High-concentration VOCs process exhaust gas enters the lift valve group 3 through pipe 1. Linear cylinder 4 pushes valve plate 4-1 to close vent hole 3-4 and open vent hole 3-3. Linear cylinder 5 pushes valve plate 5-1 to close vent hole 3-5 and open vent hole 3-6. The high-concentration VOCs process exhaust gas passes through vent holes 3-3 and 3-1 sequentially, and enters heat exchanger group 8 through channel 6. Within heat exchanger group 8, the high-concentration VOCs process exhaust gas passes sequentially through heat exchanger 14, demister 15, and heat exchanger 13. Heat exchanger 14, used to cool the high-concentration VOCs process exhaust gas, stops operating, i.e., water supply valve 12 is closed. As the high-concentration VOCs process exhaust gas passes through heat exchanger 14, the heat exchanger uses the relatively high temperature of the high-concentration VOCs process exhaust gas to defrost the heat exchanger. At the same time, the high-concentration VOCs process exhaust gas is also cooled for the first time. After the high-concentration VOCs process exhaust gas is first cooled, it passes through a demister 15 to remove droplets from defrosting before entering the next stage heat exchanger 13 for further cooling. At this time, the chilled water supply valve 11 is open, providing a cold source to the heat exchanger 13. The high-concentration VOCs process exhaust gas is further cooled to 0°C or below in the heat exchanger 13, removing moisture. The removed moisture forms condensate or freezes in the heat exchanger 13. The high-concentration VOCs process exhaust gas, cooled to below 0°C, re-enters the lift valve assembly through channel 7, passes through vents 3-2 and 3-6 in sequence, and is then discharged from the system through pipe 2, thus achieving the purpose of removing moisture and simultaneously defrosting the system.

[0061] As the system operates consistently, frost / ice will gradually increase within heat exchanger 13, leading to a gradual increase in the overall system pressure drop. Differential pressure gauges 17, installed at the system inlet and outlet, monitor the overall system pressure drop through the control system.

[0062] When the pressure drop reaches the set value X1, the control system opens the chilled water supply valve 12 and closes the supply valve 11. At the same time, the linear cylinder 4 of the lifting valve group retracts the valve rod, causing the valve plate 4-1 to open the vent 3-4 and close the vent 3-3; the linear cylinder 5 pushes the valve plate 5-1 to open the vent 3-5 and close the vent 3-6.

[0063] When the system is in the above state, the high-concentration VOCs process exhaust gas enters the riser valve group through pipe 1 and then enters the heat exchanger group 8 through vents 3-4, 3-2 and pipe 7. Inside the heat exchanger group 8, the high-concentration VOCs process exhaust gas uses its relatively high temperature to heat and defrost the heat exchanger 13. The high-concentration VOCs process exhaust gas is cooled for the first time. Then, it passes through the demister 15 to remove the droplets formed after defrosting or cooling before entering the heat exchanger 14 for further cooling. Inside the heat exchanger 14, the high-concentration VOCs process exhaust gas is further cooled to below 0°C. The moisture in it is further condensed and precipitated, and may even solidify into frost / ice. After the moisture is removed, it enters the riser valve group through channel 6. Inside the riser valve group, it sequentially passes through vents 3-5 and pipe 2 to exit the system, thereby achieving the purpose of removing moisture while defrosting the system.

[0064] This system typically includes an electrical control system. The monitoring of linear cylinders 4 and 5, chilled water supply valves 11 and 12, and differential pressure monitoring instrument 17 is all handled by this control system. The control system has a setpoint for the differential pressure monitoring instrument 17, which controls the switching of linear cylinders 4 and 5, and water supply valves 11 and 12. The electrical control system uses a PLC programmable controller to control the movement of the linear cylinder solenoid valves, and simultaneously controls the differential pressure value set by the differential pressure monitoring instrument to close and open each valve, thus switching between different operations. The differential pressure value is the difference between the inlet pressure display value and the outlet pressure display value of the later-stage filter.

[0065] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and substitutions without departing from the technical principles of the present invention, and these improvements and substitutions are all considered to be within the protection scope of the present invention.

Claims

1. A heat exchanger assembly designed to prevent frost blockage, characterized in that, The system includes a heat exchanger mechanism, a lift valve assembly mechanism, and an electrical control system. The heat exchanger mechanism and the lift valve assembly mechanism are connected via a first channel and a second channel. The lower end of the heat exchanger mechanism is connected to a first heat exchange pipe and a second heat exchange pipe, respectively. A water supply control device is installed on the first heat exchange pipe. A cylinder control device is installed on the lift valve assembly mechanism. The electrical control system is connected to both the water supply control device and the cylinder control device. The heat exchanger mechanism includes a heat exchange chamber, inside which a first heat exchanger, a second heat exchanger, and a demister are installed. A demister is installed to the right of the first heat exchanger, and a second heat exchanger is installed to the right of the demister. The lift valve assembly mechanism includes an inner valve mechanism, a first exhaust gas pipe, and a second exhaust gas pipe. One end of the inner valve mechanism is connected to the first exhaust gas pipe, and the other end is connected to the second exhaust gas pipe. The lift valve assembly mechanism is connected to a first linear cylinder and a second linear cylinder of the cylinder control device. The inner valve mechanism includes an inner valve housing and multiple air chambers. The inner valve housing is provided with multiple air chambers, including a first air chamber, a second air chamber, and a third air chamber. The second air chamber is located at the lower end of the first air chamber, and the third air chamber is located at the lower end of the second air chamber. The first air chamber is connected to the second air chamber through a third air hole and a fifth air hole, and the second air chamber is connected to the third air chamber through a fourth air hole and a sixth air hole. The first air chamber is provided with a first air hole, which divides the first air chamber into two spaces. The second air chamber includes a left chamber and a right chamber. The left chamber and the right chamber are connected by a locking valve, which is fixed to the inner valve box. The third air chamber is provided with a second air hole, which divides the third air chamber into two spaces. The inner valve box is connected to the first air chamber, the second air chamber and the third air chamber by a first linear cylinder and a second linear cylinder. The first linear cylinder is provided with a first valve plate and the second linear cylinder is provided with a second valve plate. The first valve plate controls the third air port and the fourth air port, and the second valve plate controls the fifth air port and the sixth air port.

2. A heat exchanger assembly for preventing frost blockage according to claim 1, characterized in that, The left cavity is connected to the first exhaust gas pipe, and the right cavity is connected to the second exhaust gas pipe.

3. A heat exchanger assembly for preventing frost blockage according to claim 2, characterized in that, The water supply control device includes a first water supply valve and a second water supply valve. The first water supply valve and the second water supply valve are respectively installed on the first heat exchange pipe. The first water supply valve is connected to the first heat exchanger, and the second water supply valve is connected to the second heat exchanger. The second heat exchange pipe is connected to the first heat exchanger and the second heat exchanger respectively.

4. A heat exchanger assembly for preventing frost blockage according to claim 3, characterized in that, Differential pressure monitoring instruments are respectively installed on the first exhaust gas pipe and the second exhaust gas pipe. The differential pressure information of the differential pressure monitoring instruments is transmitted to the electrical control system. Through the feedback of the differential pressure information, the electrical control system controls the water supply control device and the cylinder control device.

5. A heat exchanger assembly for preventing frost blockage according to claim 4, characterized in that, The demister is equipped with a drain valve at its lower end. The demister includes a demister housing, which is located within a heat exchanger mechanism. The demister housing contains multiple layers of filter grids, and each of the multiple filter grids is equipped with a bead condensation linkage device. The number of layers in the multiple filter grids is greater than 10.

6. A heat exchanger assembly for preventing frost blockage according to claim 5, characterized in that, The bead-coating linkage device includes a linkage plate, on which an elastic tension member is provided at its lower end. The elastic tension member is connected between the linkage plate and the filter grid plate. The linkage plate is inclinedly disposed on the filter grid plate and moves on the filter grid plate through a through shaft. A bead-coating ball is disposed on the filter grid plate at the upper end of the linkage plate. The diameter of the bead-coating ball is larger than the distance between the upper end of the linkage plate and the filter grid plate.

7. A control method for preventing frost blockage in a heat exchanger assembly, characterized in that, The heat exchanger assembly for preventing frost blockage is a heat exchanger assembly for preventing frost blockage as described in any one of claims 4 to 6, comprising the following steps: S1: High-concentration VOCs process tail gas enters the lifting valve group mechanism from the first tail gas pipeline. The first linear cylinder of the electrical control system pushes the first valve plate to close the fourth air hole and open the third air hole. The second linear cylinder pushes the second valve plate to close the fifth air hole and open the sixth air hole. The high-concentration VOCs process tail gas enters the heat exchanger mechanism through the third air hole and the first air hole in sequence, and enters the heat exchanger mechanism through the first channel. In the heat exchanger mechanism, the high-concentration VOCs process tail gas passes through the second heat exchanger, the demister and the first heat exchanger in sequence. S2: When the high-concentration VOCs process tail gas passes through the second heat exchanger, the second heat exchanger uses the relatively high temperature of the high-concentration VOCs process tail gas to defrost the heat exchanger. At the same time, the high-concentration VOCs process tail gas is also cooled down for the first time. After the high-concentration VOCs process tail gas is cooled down for the first time, it passes through a demister to remove the liquid droplets from the defrosting process, and then enters the first heat exchanger of the next stage for further cooling. S3: At this time, the first water supply valve is open, the first heat exchanger provides a cold source, and the high-concentration VOCs process tail gas is further cooled to 0°C or below in the first heat exchanger. The water in it is removed, and the removed water forms condensate or freezes in the first heat exchanger. The high-concentration VOCs process tail gas cooled to below 0°C re-enters the lift valve group mechanism through the second channel, passes through the second air hole and the sixth air hole in sequence, and is discharged from the system through the second tail gas pipe, thereby achieving the purpose of removing water and defrosting the system at the same time. S4: As the system continues to run, the frost / ice in the first heat exchanger will gradually increase, and the pressure drop of the entire system will gradually increase. The differential pressure monitoring instruments installed in the first and second tail gas pipelines of this device monitor the pressure drop of the entire system through the electrical control system. S5: When the pressure drop reaches the set value, the electrical control system opens the second water supply valve and closes the first water supply valve. At the same time, the first linear cylinder is lifted to retract the valve rod, which drives the first valve plate to open the fourth air hole and close the third air hole. The second linear cylinder pushes the second valve plate to open the fifth air hole and close the sixth air hole. S6: During system step S5, the high-concentration VOCs process tail gas enters the lift valve assembly through the first tail gas pipe and then enters the heat exchanger assembly via the fourth vent, the second vent, and the second channel. Inside the heat exchanger assembly, the high-concentration VOCs process tail gas uses its relatively high temperature to heat and defrost the first heat exchanger. The high-concentration VOCs process tail gas is cooled for the first time, and then passes through a demister to remove the droplets formed after defrosting or cooling before entering the second heat exchanger for further cooling. Inside the second heat exchanger, the high-concentration VOCs process tail gas is further cooled to below 0°C, and the moisture in it is further condensed and precipitated, or even solidified into frost / ice. After the moisture is removed, it enters the lift valve assembly through the first channel and then exits the system through the fifth vent and the second tail gas pipe in sequence, thereby achieving the purpose of removing moisture while defrosting the system.

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