A freeze-drying system suitable for low-pressure circulating water working conditions in the chlor-alkali industry

Abstract

The utility model relates to the technical field of freeze drying equipment, specifically relates to a freeze drying system suitable for chlor alkali industry low pressure circulating water working condition, including buffer tank, buffer tank is connected with the shell side entrance of pre -cooler, the shell side export of pre -cooler is connected with the shell side entrance of evaporimeter, the shell side export of pre -cooler sets up temperature detection device, the shell side export of evaporimeter is connected with separator, the pipe side export of evaporimeter is connected with refrigerant compressor, refrigerant compressor is connected with the shell side entrance of air -cooled condenser, the shell side export of air -cooled condenser is connected with refrigerant drying filter, refrigerant drying filter is connected with expansion valve, and the pipe side entrance of evaporimeter is connected with expansion valve, the pipe side entrance of pre -cooler is connected with circulating water pool through circulating water pipeline, and circulating water pipeline includes three parallel branch lines, and the pipe side entrance of air -cooled condenser is also connected with circulating water pool. The system can be used in chlor alkali industry low pressure circulating water working condition, and the separation effect of dry air is good.

Description

Technical Field

[0001] This utility model relates to the field of freeze-drying equipment technology, specifically to a freeze-drying system suitable for low-pressure circulating water conditions in the chlor-alkali industry. Background Technology

[0002] As a key piece of equipment for dehydrating and purifying compressed air, the core principle of a freeze dryer is to cool compressed air containing saturated water vapor to below its dew point through the phase change and heat absorption of the refrigerant in the evaporator. This causes the water vapor to condense into liquid water, which is then separated into gas and water in a separator before being discharged, thus obtaining dry air. This dried air is widely used in various industrial scenarios where the quality of the air source is critical.

[0003] In the chlor-alkali industry, due to the special nature of the production process, open circulating water systems are commonly used in processes such as rectification and chlorination / hydrogenation. This results in the circulating water pressure being maintained at a low level of around 0.2 MPa for extended periods. This low-pressure circulating water condition poses a significant challenge to the stable operation of the freeze dryer: when the low-pressure circulating water flows through the cooling system of the freeze dryer, the flow rate and velocity are difficult to achieve ideal conditions, directly causing a substantial decrease in the heat exchange efficiency of the freeze dryer.

[0004] Meanwhile, the temperature of the compressed air output from the buffer tank in chlor-alkali production is typically above 55°C, containing a large amount of saturated water vapor. When the cooling capacity of the low-pressure circulating water is insufficient, the direct entry of this high-temperature compressed air into the evaporator forces it to bear an extremely high refrigeration load. This not only causes the compressor of the refrigerated dryer to operate at high energy consumption for extended periods, but also leads to frequent compressor start-ups and shutdowns or exhaust overheating due to drastic load fluctuations, severely impacting equipment lifespan and even causing unplanned shutdowns. Current technologies often address these issues by increasing the power of the refrigeration unit. While this can alleviate the insufficient cooling problem to some extent, it results in a surge in energy consumption, contradicting the current industry trend of energy conservation and emission reduction, and is also unsuitable for the special operating conditions of low-pressure circulating water in the chlor-alkali industry. Utility Model Content

[0005] To address the technical problems of poor compressed air treatment effect, high energy consumption, and poor stability under low-pressure circulating water conditions in the chlor-alkali industry, this utility model provides a freeze-drying system suitable for low-pressure circulating water conditions in the chlor-alkali industry.

[0006] The technical solution provided by this utility model is as follows:

[0007] A freeze-drying system suitable for low-pressure circulating water conditions in the chlor-alkali industry includes a buffer tank, which is connected to the shell-side inlet of a precooler, and the shell-side outlet of the precooler is connected to the shell-side inlet of an evaporator. A temperature detection device is installed at the shell-side outlet of the precooler, and the shell-side outlet of the evaporator is connected to a separator. An air outlet pipe and a liquid drain pipe are installed on the separator.

[0008] The tube-side outlet of the evaporator is connected to the refrigerant compressor, the refrigerant compressor is connected to the shell-side inlet of the air-cooled condenser, the shell-side outlet of the air-cooled condenser is connected to the refrigerant dryer filter, the refrigerant dryer filter is connected to the expansion valve, and the expansion valve is connected to the tube-side inlet of the evaporator.

[0009] The tube-side inlet of the precooler is connected to the circulating water tank via a circulating water pipeline, which includes three parallel branches, each with a solenoid valve. The tube-side inlet of the air-cooled condenser is also connected to the circulating water tank.

[0010] Furthermore, the pipes inside the precooler exhibit a continuous multi-U-shaped bend structure.

[0011] Furthermore, an automatic drain is connected to the end of the drain pipe.

[0012] Furthermore, the expansion valve is an external pressure equalization and temperature sensing automatic expansion valve.

[0013] Furthermore, the diameter of the end of the circulating water pipeline connected to the precooler is DN80.

[0014] Furthermore, the diameter of the end of the circulating water pipeline connected to the circulating water tank is DN80.

[0015] Furthermore, the diameter of the three parallel branches of the circulating water pipeline is DN32.

[0016] Furthermore, the openings of the three parallel branches of the circulating water pipeline are different.

[0017] Furthermore, the openings of the three parallel branches of the circulating water pipeline are 50%, 75%, and 100%, respectively.

[0018] A 50% opening is the base flow rate.

[0019] Furthermore, a first electrical contact pressure gauge is installed on the tube side of the evaporator, and the signal output terminal of the first electrical contact pressure gauge is connected to the alarm device; a second electrical contact pressure gauge is installed on the tube side of the air-cooled condenser, and the signal output terminal of the second electrical contact pressure gauge is also connected to the alarm device.

[0020] The beneficial effects of this utility model are as follows:

[0021] This invention provides a freeze-drying system for low-pressure circulating water conditions in the chlor-alkali industry. Firstly, by incorporating a precooler and employing a three-branch staged flow control technology, the freeze-drying system can stably precool high-temperature compressed air (55°C) to approximately 30°C under 0.2MPa low-pressure circulating water conditions. This optimization significantly reduces the heat load on the evaporator, substantially improves the dehumidification efficiency of the freeze-drying system, avoids drastic load fluctuations in the refrigerant compressor caused by high-temperature intake air, and provides excellent separation of the dried air. Secondly, the staged flow control can adjust the circulating water flow according to actual temperature requirements, avoiding unnecessary waste of water and energy. Furthermore, the stable operating conditions effectively extend the service life of the refrigerant compressor and key components, improving the adaptability and reliability of the freeze-drying system in the harsh environment of the chlor-alkali industry, providing strong support for continuous production, and ultimately achieving a dual improvement in production and economic benefits. Attached Figure Description

[0022] To more clearly illustrate the technical solution of this utility model, the drawings used in the description will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the freeze-drying system of prior art 1.

[0024] Figure 2 This is a schematic diagram of the freeze-drying system of Example 1.

[0025] Figure 3 This is a schematic diagram of the freeze-drying system of prior art 2.

[0026] Figure 4 This is a schematic diagram of the freeze-drying system in Example 2.

[0027] In the diagram, 1-evaporator, 2-separator, 3-automatic drainer, 4-refrigerant compressor, 5-air-cooled condenser, 6-refrigerant dryer filter, 7-expansion valve, 8-alarm device, 9-circulating water tank, 10-solenoid valve, 11-precooler, 12-buffer tank. Detailed Implementation

[0028] To make the objectives, features, and advantages of this utility model more apparent and understandable, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0029] Prior Art 1

[0030] like Figure 1 As shown, a freeze-drying system includes a buffer tank 12, which is connected to the shell-side inlet of an evaporator 1. The shell-side outlet of the evaporator 1 is connected to a separator 2. The separator 2 is provided with an exhaust pipe and a drain pipe, and the end of the drain pipe is connected to an automatic drainer 3.

[0031] The tube-side outlet of evaporator 1 is connected to refrigerant compressor 4. Refrigerant compressor 4 is connected to shell-side inlet of air-cooled condenser 5. Shell-side outlet of air-cooled condenser 5 is connected to refrigerant dryer filter 6. Refrigerant dryer filter 6 is connected to expansion valve 7. Expansion valve 7 is connected to tube-side inlet of evaporator 1. Expansion valve 7 is an external pressure equalization temperature sensing automatic expansion valve.

[0032] The tube inlet of the air-cooled condenser 5 is connected to the circulating water tank 9.

[0033] The outlet of the automatic drainer 3 and the tube outlet of the air-cooled condenser 5 are respectively connected to the corresponding storage containers at the end of the gas outlet pipe of the separator 2.

[0034] During operation, compressed air (above 55℃) in buffer tank 12 enters the shell side of evaporator 1. At this time, refrigerant compressor 4 compresses Freon gas into high-temperature and high-pressure Freon gas. The high-temperature and high-pressure Freon gas enters air-cooled condenser 5 for heat exchange. The high-temperature and high-pressure Freon gas flows through the shell side of air-cooled condenser 5, while the low-pressure circulating water flowing out of circulating water tank 9 flows through the tube side of air-cooled condenser 5. After heat exchange, the high-temperature and high-pressure Freon gas becomes low-temperature and low-pressure Freon gas. After the low-temperature and low-pressure Freon gas passes through refrigerant dryer filter 6 to remove water, it is then throttled by expansion valve 7 into low-pressure and low-temperature Freon liquid. The low-pressure and low-temperature Freon liquid enters the tube side of evaporator 1 and exchanges heat with the compressed air in the shell side of evaporator 1. After heat exchange, the low-pressure and low-temperature Freon liquid vaporizes (Freon can vaporize at 2-3℃ under vacuum in evaporator), and then enters refrigerant compressor 4 for compression, repeating the cycle. Compressed air undergoes heat exchange in evaporator 1, completing a vapor-liquid condensation phase change. It then enters separator 2 for gas-liquid separation. The dried air is discharged through the outlet at the top of separator 2, while the mixture of water and oil droplets is discharged from the drain pipe of separator 2. After passing through automatic drainer 3, the water and oil are separated and stored separately. Before the modification, the circulating water in circulating water tank 9 was an open circulating water system for the rectification and chlorination / hydrogenation processes, and the circulating water pressure was consistently maintained at a low pressure of approximately 0.2 MPa. Under these conditions, the low-pressure circulating water could not achieve sufficient heat exchange in the freeze dryer (i.e., the remaining portion of the existing freeze dryer system excluding buffer tank 12 and circulating water tank 9), resulting in the compressed air entering the freeze dryer not being effectively cooled. Consequently, the dryness of the compressed air after separation by separator 2 was substandard, severely affecting the subsequent process results.

[0035] Example 1

[0036] By modifying the freeze-drying system of existing technology 1, this embodiment 1 provides a freeze-drying system suitable for low-pressure circulating water conditions in the chlor-alkali industry, such as... Figure 2 As shown, it includes a buffer tank 12, which is connected to the shell-side inlet of the precooler 11. A temperature detection device is installed at the shell-side outlet of the precooler 11. The shell-side outlet of the precooler 11 is connected to the shell-side inlet of the evaporator 1. The shell-side outlet of the evaporator 1 is connected to the separator 2. The separator 2 is provided with an exhaust pipe and a drain pipe, and the end of the drain pipe is connected to an automatic drainer 3. The pipes inside the precooler 11 have a continuous multi-U-shaped bend structure.

[0037] The tube-side outlet of evaporator 1 is connected to refrigerant compressor 4. Refrigerant compressor 4 is connected to shell-side inlet of air-cooled condenser 5. Shell-side outlet of air-cooled condenser 5 is connected to refrigerant dryer filter 6. Refrigerant dryer filter 6 is connected to expansion valve 7. Expansion valve 7 is connected to tube-side inlet of evaporator 1. Expansion valve 7 is an external pressure equalization temperature sensing automatic expansion valve.

[0038] The tube-side inlet of the precooler 11 is connected to the circulating water tank 9 via a circulating water pipeline. This circulating water pipeline includes three parallel branches with different opening degrees: 50%, 75%, and 100%. Each circulating water branch is equipped with a solenoid valve 10. The solenoid valve 10 on the circulating water branch with a 50% opening is the first solenoid valve, the solenoid valve 10 on the circulating water branch with a 75% opening is the second solenoid valve, and the solenoid valve 10 on the circulating water branch with a 100% opening is the third solenoid valve. The diameter of the circulating water pipeline is DN80 at the end connected to the precooler 11 and at the end connected to the circulating water tank 9. The diameter of the three parallel branches of the circulating water pipeline is DN32. The tube-side inlet of the air-cooled condenser 5 is also connected to the circulating water tank 9.

[0039] A first electric contact pressure gauge is installed on the tube side of the evaporator 1, and the signal output terminal of the first electric contact pressure gauge is connected to the alarm device 8; a second electric contact pressure gauge is installed on the tube side of the air-cooled condenser 5, and the signal output terminal of the second electric contact pressure gauge is also connected to the alarm device 8.

[0040] The tube-side outlet of the precooler 11, the end of the gas outlet pipe of the separator 2, the outlet of the automatic drainer 3, and the tube-side outlet of the air-cooled condenser 5 are respectively connected to the corresponding storage containers.

[0041] During operation, compressed air (above 55°C) from buffer tank 12 enters the shell side of precooler 11. At this time, circulating water from circulating water tank 9 first enters precooler 11 through a circulating water branch with an opening of 50% (50% being the base opening) to cool the compressed air. After one minute, the temperature detection device checks the temperature. If the temperature has not dropped to 30°C, the second solenoid valve is opened, and circulating water also flows through the second circulating water branch with an opening of 75% to enter precooler 11 to cool the compressed air. After one minute, the temperature detection device checks the temperature again. If the temperature has still not dropped to 30°C, the third solenoid valve is opened, and circulating water also flows through the third solenoid valve. The third circulating water branch, with a temperature of 100%, enters the precooler 11 to cool the compressed air. If, after approximately five minutes, the temperature detection device detects that the temperature has not yet dropped to 30°C, the compressed air above 30°C continues to enter the evaporator 1. If the first electrical contact pressure gauge detects a discrepancy between the pressure value in the tube side of the evaporator 1 and the set range, a pressure signal is sent to the alarm device 8, which then issues an alarm. Alternatively, if the second electrical contact pressure gauge detects a discrepancy between the pressure value in the tube side of the air-cooled condenser 5 and the set range, a pressure signal is sent to the alarm device 8, which then issues an alarm. Upon hearing this, relevant personnel will stop the machine for rectification. If the temperature drops to 30°C after opening the first circulating water branch, the second and third circulating water branches do not need to be opened; if the temperature drops to 30°C after opening the second circulating water branch, the third circulating water branch does not need to be opened. After the compressed air reaches a temperature of 30°C at the shell-side outlet of the precooler 11, it enters the shell side of the evaporator 1.

[0042] At this time, the refrigerant compressor 4 compresses the Freon gas into high-temperature, high-pressure Freon gas. The high-temperature, high-pressure Freon gas enters the air-cooled condenser 5 for heat exchange. The shell side of the air-cooled condenser 5 carries the high-temperature, high-pressure Freon gas, while the tube side carries the low-pressure circulating water flowing out of the circulating water tank 9. After heat exchange, the high-temperature, high-pressure Freon gas becomes low-temperature, low-pressure Freon gas. After the low-temperature, low-pressure Freon gas passes through the refrigerant dryer filter 6 to remove water, it is then throttled by the expansion valve 7 into low-pressure, low-temperature Freon liquid. The low-pressure, low-temperature Freon liquid enters the tube side of the evaporator 1 and exchanges heat with the compressed air in the shell side of the evaporator 1. After heat exchange, the low-pressure, low-temperature Freon liquid vaporizes (Freon can vaporize at 2-3℃ under vacuum in the evaporator), and then enters the refrigerant compressor 4 for compression, repeating the cycle. After heat exchange in the evaporator 1, the compressed air undergoes a vapor-liquid condensation phase change and then enters the separator 2 for gas-liquid separation. The dry air is discharged through the outlet at the top of the separator 2, while the mixture of water and oil droplets is discharged from the drain pipe of the separator 2 and then separated into water and oil by the automatic drainer 3, and stored separately. After the modification, the circulating water in the circulating water tank 9 also cools the compressed air in the precooler 11, improving the cooling and water-liquid separation effect of the air compressor (i.e., the remaining part of the freeze-drying system in Example 1 excluding the buffer tank 12 and the circulating water tank 9), stabilizing the operating conditions, effectively extending the service life of the compressor and key components, and making full use of water resources by controlling the precooling effect of the precooler 11 through the flow distribution of three circulating water branches.

[0043] Existing technology 2

[0044] like Figure 3 As shown, a freeze-drying system includes a buffer tank 12, which is connected to the shell-side inlet of an evaporator 1. The shell-side outlet of the evaporator 1 is connected to a separator 2, and the separator 2 is provided with an outlet pipe and a drain pipe.

[0045] The tube side outlet of evaporator 1 is connected to refrigerant compressor 4. Refrigerant compressor 4 is connected to shell side inlet of air-cooled condenser 5. Shell side outlet of air-cooled condenser 5 is connected to refrigerant dryer filter 6. Refrigerant dryer filter 6 is connected to expansion valve 7. Expansion valve 7 is connected to tube side inlet of evaporator 1. Expansion valve 7 is an external pressure equalization temperature sensing automatic expansion valve.

[0046] The tube inlet of the air-cooled condenser 5 is connected to the circulating water tank 9.

[0047] The gas outlet pipe end, the liquid drain pipe end, and the tube outlet of the air-cooled condenser 5 are respectively connected to the corresponding storage containers.

[0048] During operation, compressed air (above 55℃) in buffer tank 12 enters the shell side of evaporator 1. At this time, refrigerant compressor 4 compresses Freon gas into high-temperature and high-pressure Freon gas. The high-temperature and high-pressure Freon gas enters air-cooled condenser 5 for heat exchange. The high-temperature and high-pressure Freon gas flows through the shell side of air-cooled condenser 5, while the low-pressure circulating water flowing out of circulating water tank 9 flows through the tube side of air-cooled condenser 5. After heat exchange, the high-temperature and high-pressure Freon gas becomes low-temperature and low-pressure Freon gas. After the low-temperature and low-pressure Freon gas passes through refrigerant dryer filter 6 to remove water, it is then throttled by expansion valve 7 into low-pressure and low-temperature Freon liquid. The low-pressure and low-temperature Freon liquid enters the tube side of evaporator 1 and exchanges heat with the compressed air in the shell side of evaporator 1. After heat exchange, the low-pressure and low-temperature Freon liquid vaporizes (Freon can vaporize at 2-3℃ under vacuum in evaporator), and then enters refrigerant compressor 4 for compression, repeating the cycle. The compressed air undergoes heat exchange in evaporator 1, completing a vapor-liquid condensation phase change, and then enters separator 2 for gas-liquid separation. The dry air is discharged through the outlet at the top of separator 2, while the mixture of water and oil droplets is discharged through the drain pipe of separator 2. Before the modification, the circulating water in circulating water tank 9 was an open circulating water system for the rectification and chlorination processes, and the circulating water pressure was maintained at a low pressure of about 0.2 MPa for a long time. Under this condition, the low-pressure circulating water could not achieve sufficient heat exchange in the freeze dryer (i.e., the remaining part of the existing freeze dryer system 2 excluding buffer tank 12 and circulating water tank 9), resulting in the compressed air entering the freeze dryer not being effectively cooled. Ultimately, the dryness of the compressed air separated by separator 2 was substandard, seriously affecting the subsequent process effects.

[0049] Example 2

[0050] By modifying the freeze-drying system of existing technology 2, this embodiment 2 provides a freeze-drying system suitable for low-pressure circulating water conditions in the chlor-alkali industry, such as... Figure 4 As shown, it includes a buffer tank 12, which is connected to the shell-side inlet of the precooler 11. A temperature detection device is installed at the shell-side outlet of the precooler 11. The shell-side outlet of the precooler 11 is connected to the shell-side inlet of the evaporator 1. The shell-side outlet of the evaporator 1 is connected to the separator 2. An outlet pipe and a drain pipe are installed on the separator 2. The pipes inside the precooler 11 have a continuous U-shaped bend structure.

[0051] The tube-side outlet of evaporator 1 is connected to refrigerant compressor 4. Refrigerant compressor 4 is connected to shell-side inlet of air-cooled condenser 5. Shell-side outlet of air-cooled condenser 5 is connected to refrigerant dryer filter 6. Refrigerant dryer filter 6 is connected to expansion valve 7. Expansion valve 7 is connected to tube-side inlet of evaporator 1. Expansion valve 7 is an external pressure equalization temperature sensing automatic expansion valve.

[0052] The tube inlet of the precooler 11 is connected to the circulating water tank 9 via a circulating water pipeline. This circulating water pipeline includes three parallel branches with different opening degrees: 50%, 75%, and 100%. Each circulating water branch is equipped with a solenoid valve 10. The solenoid valve 10 on the circulating water branch with an opening degree of 50% is the first solenoid valve, the solenoid valve 10 on the circulating water branch with an opening degree of 75% is the second solenoid valve, and the solenoid valve 10 on the circulating water branch with an opening degree of 100% is the third solenoid valve. The diameter of the end of the circulating water pipeline connected to the precooler 11 is DN80, the diameter of the end of the circulating water pipeline connected to the circulating water tank 9 is DN80, and the diameter of the three parallel branches of the circulating water pipeline is DN32.

[0053] The tube outlet of the precooler 11, the end of the gas outlet pipe of the separator 2, the end of the liquid discharge pipe, and the tube outlet of the air-cooled condenser 5 are respectively connected to the corresponding storage containers.

[0054] During operation, compressed air (above 55°C) from buffer tank 12 enters the shell side of precooler 11. At this time, circulating water from circulating water pool 9 first enters precooler 11 through a circulating water branch with an opening of 50% (50% is the basic opening) to cool the compressed air. After one minute, the temperature detection device checks the temperature. If the temperature has not dropped to 30°C, the second solenoid valve is opened, and circulating water also flows through the second circulating water branch with an opening of 75% to enter precooler 11 to cool the compressed air. After one minute, the temperature detection device checks the temperature again. If the temperature has still not dropped to 30°C, the third solenoid valve is opened, and circulating water also flows through the third circulating water branch with an opening of 100% to enter precooler 11 to cool the compressed air. If, after about five minutes, relevant personnel observe that the temperature detected by the temperature detection device has still not dropped to 30°C, a shutdown and rectification operation is performed. If the temperature drops to 30°C after opening the first circulating water branch, there is no need to open the second or third circulating water branch; if the temperature drops to 30°C after opening the second circulating water branch, there is no need to open the third circulating water branch. Compressed air enters the shell side of the evaporator 1 after the temperature at the shell-side outlet of the precooler 11 drops to 30°C.

[0055] At this time, the refrigerant compressor 4 compresses the Freon gas into high-temperature, high-pressure Freon gas. The high-temperature, high-pressure Freon gas enters the air-cooled condenser 5 for heat exchange. The shell side of the air-cooled condenser 5 carries the high-temperature, high-pressure Freon gas, while the tube side carries the low-pressure circulating water flowing out of the circulating water tank 9. After heat exchange, the high-temperature, high-pressure Freon gas becomes low-temperature, low-pressure Freon gas. After the low-temperature, low-pressure Freon gas passes through the refrigerant dryer filter 6 to remove water, it is then throttled by the expansion valve 7 into low-pressure, low-temperature Freon liquid. The low-pressure, low-temperature Freon liquid enters the tube side of the evaporator 1 and exchanges heat with the compressed air in the shell side of the evaporator 1. After heat exchange, the low-pressure, low-temperature Freon liquid vaporizes (Freon can vaporize at 2-3℃ under vacuum in the evaporator), and then enters the refrigerant compressor 4 for compression, repeating the cycle. After heat exchange in the evaporator 1, the compressed air undergoes a vapor-liquid condensation phase change and then enters the separator 2 for gas-liquid separation. The dry air is discharged through the outlet at the top of the separator 2, while the mixture of water and oil droplets is discharged from the drain pipe of the separator 2. After the modification, the circulating water in the circulating water tank 9 also cools the compressed air in the precooler 11, improving the cooling and water-liquid separation effect of the air compressor (i.e., the remaining part of the freeze-drying system in Example 2 excluding the buffer tank 12 and the circulating water tank 9), stabilizing the operating conditions, effectively extending the service life of the compressor and key components, and making full use of water resources by controlling the precooling effect of the precooler 11 through the flow distribution of three circulating water branches.

[0056] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A freeze-drying system suitable for low-pressure circulating water conditions in the chlor-alkali industry, comprising a buffer tank (12), characterized in that, The buffer tank (12) is connected to the shell-side inlet of the precooler (11), the shell-side outlet of the precooler (11) is connected to the shell-side inlet of the evaporator (1), a temperature detection device is installed at the shell-side outlet of the precooler (11), the shell-side outlet of the evaporator (1) is connected to the separator (2), and an outlet pipe and a drain pipe are installed on the separator (2). The tube side outlet of the evaporator (1) is connected to the refrigerant compressor (4), the refrigerant compressor (4) is connected to the shell side inlet of the air-cooled condenser (5), the shell side outlet of the air-cooled condenser (5) is connected to the refrigerant dryer filter (6), the refrigerant dryer filter (6) is connected to the expansion valve (7), and the expansion valve (7) is connected to the tube side inlet of the evaporator (1). The tube inlet of the precooler (11) is connected to the circulating water tank (9) through the circulating water pipeline. The circulating water pipeline includes three parallel branches, and a solenoid valve (10) is installed on each circulating water branch. The tube inlet of the air-cooled condenser (5) is also connected to the circulating water tank (9).

2. The freeze-drying system for low-pressure circulating water conditions in the chlor-alkali industry as described in claim 1, characterized in that, The pipes inside the precooler (11) have a continuous U-shaped bend structure.

3. The freeze-drying system for low-pressure circulating water conditions in the chlor-alkali industry as described in claim 1, characterized in that, An automatic drainer (3) is connected to the end of the drain pipe.

4. The freeze-drying system for low-pressure circulating water conditions in the chlor-alkali industry as described in claim 1, characterized in that, The expansion valve (7) is an external pressure equalization temperature sensing automatic expansion valve.

5. The freeze-drying system for low-pressure circulating water conditions in the chlor-alkali industry as described in claim 1, characterized in that, The diameter of the pipe at the end of the circulating water pipeline connected to the precooler (11) is DN80.

6. The freeze-drying system for low-pressure circulating water conditions in the chlor-alkali industry as described in claim 1, characterized in that, The diameter of the pipe at one end of the circulating water pipeline connected to the circulating water tank (9) is DN80.

7. The freeze-drying system for low-pressure circulating water conditions in the chlor-alkali industry as described in claim 1, characterized in that, The diameter of the three parallel branches of the circulating water pipeline is DN32.

8. A freeze-drying system suitable for low-pressure circulating water conditions in the chlor-alkali industry as described in claim 1 or claim 7, characterized in that, The three parallel branches of the circulating water pipeline have different openings.

9. A freeze-drying system suitable for low-pressure circulating water conditions in the chlor-alkali industry as described in claim 8, characterized in that, The openings of the three parallel branches of the circulating water pipeline are 50%, 75%, and 100%, respectively.

10. A freeze-drying system suitable for low-pressure circulating water conditions in the chlor-alkali industry as described in claim 1, characterized in that, A first electric contact pressure gauge is installed on the tube side of the evaporator (1), and the signal output terminal of the first electric contact pressure gauge is connected to the alarm device (8); a second electric contact pressure gauge is installed on the tube side of the air-cooled condenser (5), and the signal output terminal of the second electric contact pressure gauge is also connected to the alarm device (8).

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