A gas low-temperature dehumidification device and process

Abstract

This invention specifically relates to a low-temperature gas dehumidification device, comprising a primary condenser, a primary separator, a secondary condenser, a secondary separator, a demister, and a regenerator; the shell-side outlet of the primary condenser is connected to the shell-side inlet pipeline of the regenerator; the tube-side outlet of the primary condenser is connected to the inlet pipeline of the primary separator; the top outlet of the primary separator is connected to the tube-side inlet of the secondary condenser; the tube-side outlet of the secondary condenser is connected to the inlet pipeline of the demister; the demister outlet is connected to the inlet pipeline of the secondary separator; and the top outlet of the secondary separator is connected to the tube-side inlet pipeline of the regenerator. This invention also relates to a low-temperature gas dehumidification process. This invention is suitable for applications with high temperature and humidity and large gas flow rate variations, and the obtained dry gas has stable relative humidity, unaffected by ambient temperature and humidity.

Description

Technical Field

[0001] This invention relates to the field of low-temperature gas dehumidification technology, and in particular to a low-temperature gas dehumidification device and process. Background Technology

[0002] Low-temperature dehumidification of gases involves lowering the gas temperature to condense water vapor, separating it, and then raising the gas temperature again to obtain dry gas with lower relative humidity. Low-temperature dehumidification is a purely physical process; no adsorbents or chemical agents are involved, thus it does not pollute the gas or alter its composition. Low-temperature gas dehumidification technology is widely used in the food, pharmaceutical, metallurgical, and air conditioning industries.

[0003] The existing low-temperature dehumidification process consists of a refrigeration system and an air duct. The humid air first exchanges heat with the low-temperature evaporator, causing the temperature to drop and condensation to occur. Most of the liquid is removed by a demister, and the remaining gas exchanges heat with the condenser, causing the temperature to rise and resulting in dry gas with lower relative humidity.

[0004] To prevent condensate from freezing and clogging the flow channels, the refrigerant temperature inside the evaporator must not be lower than 0°C. In addition, due to the heat transfer temperature difference, the temperature of the humid air after heat exchange in the evaporator is usually around 10°C.

[0005] Existing low-temperature gas dehumidification processes have the following drawbacks:

[0006] 1. In order to prevent condensate from freezing and clogging the flow channels, the refrigerant temperature in the evaporator cannot be lower than 0℃. In addition, due to the heat transfer temperature difference, the temperature of the humid air after heat exchange in the evaporator is usually around 10℃, making it difficult to reach a lower dew point temperature.

[0007] 2. Existing low-temperature gas dehumidification processes require relatively stable operating conditions. When the gas flow rate fluctuates significantly, the cooling temperature also fluctuates, resulting in unstable moisture content in the obtained dry gas.

[0008] 3. Demisters cannot completely remove droplets. Existing low-temperature gas dehumidification processes use wire mesh or corrugated plates to remove droplets entrained in the gas. However, the droplets cannot be completely separated, and they re-vaporize during the reheating process, resulting in an increased moisture content in the obtained dry gas.

[0009] Therefore, existing low-temperature gas dehumidification processes are difficult to apply to situations involving high temperature and humidity, and large flow rate variations. Summary of the Invention

[0010] The purpose of this invention is to provide a low-temperature gas dehumidification process and apparatus, which is suitable for high temperature and high humidity occasions with large gas flow variation ranges, and the obtained dry gas has stable relative humidity and is not affected by ambient temperature and humidity.

[0011] To achieve the above objectives, the present invention provides the following technical solution:

[0012] A gas low-temperature dehumidification device includes a primary condenser, a primary separator, a secondary condenser, a secondary separator, a demister, and a regenerator; the shell-side outlet of the primary condenser is connected to the shell-side inlet pipeline of the regenerator; the tube-side outlet of the primary condenser is connected to the inlet pipeline of the primary separator; the top outlet of the primary separator is connected to the tube-side inlet of the secondary condenser; the tube-side outlet of the secondary condenser is connected to the inlet pipeline of the demister; the outlet of the demister is connected to the inlet pipeline of the secondary separator; and the top outlet of the secondary separator is connected to the tube-side inlet pipeline of the regenerator.

[0013] In this invention, as one possible implementation, a regulating valve is provided at the shell-side inlet of the first-stage condenser, and a first temperature sensor is provided at the shell-side outlet of the first-stage condenser; the gas low-temperature dehumidification device also includes a PLC controller.

[0014] The first temperature sensor is used to measure the shell-side outlet temperature of the first-stage condenser and send it to the PLC controller.

[0015] The PLC controller is used to adjust the opening of the regulating valve based on the difference between the measured value and the set value of the primary condenser shell-side outlet temperature, so as to maintain the primary condenser shell-side outlet temperature at the set value.

[0016] In this invention, as one possible implementation, the secondary condenser is a heat exchanger with a heat exchange medium, and the heat exchange tube bundle in the secondary condenser is immersed in the heat exchange medium; the heat exchange medium is a liquid that does not solidify or vaporize at the process temperature, including but not limited to at least one of ethylene glycol, methanol, and ethanol, or a mixture of at least one of ethylene glycol, methanol, and ethanol with water, or an aqueous solution of an inorganic salt of at least one of ethylene glycol, methanol, and ethanol;

[0017] The shell of the secondary condenser is wrapped with refrigeration pipes, and refrigerant is contained inside the refrigeration pipes; the refrigeration compressor provides cooling capacity to the refrigerant inside the refrigeration pipes.

[0018] A second temperature sensor is installed at the tube-side outlet of the secondary condenser; the second temperature sensor is used to measure the temperature at the tube-side outlet of the secondary condenser and send the data to the PLC;

[0019] A differential pressure sensor is installed between the tube-side outlet and the tube-side inlet of the secondary condenser; the differential pressure sensor is used to measure the pressure drop on the tube side of the secondary condenser and send the data to the PLC;

[0020] The PLC is also used to adjust the refrigeration power of the refrigeration compressor based on the difference between the measured value and the set value of the outlet temperature on the tube side of the secondary condenser, so as to maintain the outlet temperature on the tube side of the secondary condenser at the set value; and to adjust the refrigeration power of the refrigeration compressor based on the difference between the measured value and the set value of the pressure drop on the tube side of the secondary condenser, so as to maintain the pressure drop on the tube side of the secondary condenser at the set value.

[0021] In this invention, as one possible implementation, the demister is a container filled with a hydrophilic material, including but not limited to a container filled with a ceramic corrugated material.

[0022] In this invention, as one possible implementation method, both the primary separator and the secondary separator are gas-liquid separation devices, including but not limited to cyclone separators.

[0023] The present invention also provides a low-temperature gas dehumidification process, which uses the above-mentioned low-temperature gas dehumidification device and includes the following steps:

[0024] Moist gas is fed into the tube side of the first-stage condenser through the tube-side inlet, and the cooling medium is fed into the shell side of the first-stage condenser through the shell-side inlet. The moist gas on the tube side of the first-stage condenser exchanges heat with the cooling medium on the shell side of the first-stage condenser. The moist gas is condensed in the first stage, and the cooling medium is heated. The moist gas after condensation in the first stage is sent into the first-stage separator from the tube-side outlet of the first-stage condenser through the inlet of the first-stage separator. The heated cooling medium is sent into the shell side of the regenerator from the shell-side outlet of the first-stage condenser through the shell-side inlet of the regenerator.

[0025] The primary separator performs primary separation on the wet gas after primary condensation. The liquid after primary separation is discharged from the bottom outlet of the primary separator, and the wet gas after primary separation is sent into the tube side of the secondary condenser from the top outlet of the primary separator through the tube side inlet of the secondary condenser.

[0026] The secondary condenser performs secondary condensation on the wet gas separated in the primary stage; the wet gas after secondary condensation is sent into the demister from the tube-side outlet of the secondary condenser through the demister inlet.

[0027] The demister removes condensation from the humid gas after secondary condensation; the humid gas after demistering is sent from the demister outlet to the secondary separator inlet via the secondary separator inlet.

[0028] The secondary separator performs secondary separation on the defoamed wet gas. The liquid after secondary separation is discharged through the bottom outlet of the secondary separator, and the dry gas after secondary separation is sent into the tube side of the regenerator from the top outlet of the secondary separator through the tube side inlet of the regenerator.

[0029] The dry gas on the tube side of the regenerator exchanges heat with the cooling medium on the shell side of the regenerator. The dry gas is reheated and the cooling medium is cooled. The reheated dry gas is discharged through the tube side outlet of the regenerator, and the cooled medium is discharged through the shell side outlet of the regenerator.

[0030] In one possible implementation of this invention, during the primary condensation of humid gas, a first temperature sensor measures the shell-side outlet temperature of the primary condenser and sends it to a PLC controller; the PLC controller adjusts the opening of the regulating valve based on the difference between the measured value and the set value of the shell-side outlet temperature of the primary condenser, so as to maintain the shell-side outlet temperature of the primary condenser at the set value.

[0031] In one possible implementation of this invention, during the secondary condensation process of humid gas, a second temperature sensor measures the outlet temperature of the secondary condenser tube side and sends the data to a PLC, while a differential pressure sensor measures the pressure drop across the secondary condenser tube side and sends the data to the PLC. The PLC adjusts the refrigeration power of the compressor based on the difference between the measured and set values ​​of the secondary condenser tube side outlet temperature to maintain the outlet temperature at the set value. Similarly, the PLC adjusts the refrigeration power of the compressor based on the difference between the measured and set values ​​of the pressure drop across the secondary condenser tube side to maintain the pressure difference between the inlet and outlet of the secondary condenser tube side at the set value.

[0032] When the measured pressure drop on the tube side of the secondary condenser is higher than the set value, the humid gas on the tube side of the secondary condenser will freeze; when the measured outlet temperature on the tube side of the secondary condenser is lower than 0°C, the humid gas on the tube side of the secondary condenser will freeze.

[0033] When the measured pressure drop on the tube side of the secondary condenser exceeds a certain set value, the PLC reduces the refrigeration power of the refrigeration compressor inverter to maintain the pressure drop on the tube side of the secondary condenser within the set value.

[0034] When the measured temperature at the tube-side outlet of the secondary condenser is higher than 0°C, the PLC increases the refrigeration power of the refrigeration compressor inverter to maintain the tube-side outlet temperature of the secondary condenser at the set value.

[0035] In this invention, as one possible implementation method, the cooling medium includes, but is not limited to, cooling water and air.

[0036] Beneficial technical effects of the present invention:

[0037] The gas low-temperature dehumidification device and process of the present invention adopts a multi-stage condensation method to dehumidify gases with high temperature, high humidity and large flow variation range; it uses sensor measurement parameters to adjust the cooling power to prevent the gas from freezing during the cooling process; and it uses the cooling medium that exchanges heat with the gas for the first time in the first-stage condenser to reheat the low-temperature saturated gas after the second-stage separation, thus saving energy. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of an existing low-temperature gas dehumidification process.

[0039] Figure 2 This is a schematic diagram of the structure of an embodiment of the gas low-temperature dehumidification device of the present invention;

[0040] Figure 3 A schematic diagram illustrating the adjustment of an embodiment of a primary condenser;

[0041] Figure 4 A schematic diagram of one embodiment of a two-stage condenser;

[0042] Figure 5 A schematic diagram illustrating the refrigeration power adjustment of one embodiment of a refrigeration compressor;

[0043] Figure 6 A schematic diagram of the process for sampling and analyzing the gas blown out of boiler feedwater;

[0044] Figure 7 A graph showing the tube-side pressure drop and tube-side outlet temperature of an example of a two-stage condenser. Detailed Implementation

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having" and any variations thereof in the specification, claims, and foregoing drawings are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings are used to distinguish different objects and not to describe a particular order.

[0046] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0047] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments.

[0048] This invention provides a low-temperature gas dehumidification device, comprising a primary condenser, a primary separator, a secondary condenser, a secondary separator, a demister, and a regenerator; the shell-side outlet of the primary condenser is connected to the shell-side inlet pipeline of the regenerator; the tube-side outlet of the primary condenser is connected to the inlet pipeline of the primary separator; the top outlet of the primary separator is connected to the tube-side inlet of the secondary condenser; the tube-side outlet of the secondary condenser is connected to the inlet pipeline of the demister; the outlet of the demister is connected to the inlet pipeline of the secondary separator; and the top outlet of the secondary separator is connected to the tube-side inlet pipeline of the regenerator.

[0049] In this invention, as one possible implementation, a regulating valve is provided at the shell-side inlet of the first-stage condenser, and a first temperature sensor is provided at the shell-side outlet of the first-stage condenser; the gas low-temperature dehumidification device also includes a PLC controller.

[0050] The first temperature sensor is used to measure the shell-side outlet temperature of the first-stage condenser and send it to the PLC controller.

[0051] The PLC controller is used to adjust the opening of the regulating valve based on the difference between the measured value and the set value of the primary condenser shell-side outlet temperature, so as to maintain the primary condenser shell-side outlet temperature at the set value.

[0052] In this invention, as one possible implementation, the secondary condenser is a heat exchanger with a heat exchange medium, and the heat exchange tube bundle in the secondary condenser is immersed in the heat exchange medium; the heat exchange medium is a liquid that does not solidify or vaporize at the process temperature, including but not limited to at least one of ethylene glycol, methanol, and ethanol, or a mixture of at least one of ethylene glycol, methanol, and ethanol with water, or an aqueous solution of an inorganic salt of at least one of ethylene glycol, methanol, and ethanol;

[0053] The shell of the secondary condenser is wrapped with refrigeration pipes, and refrigerant is contained inside the refrigeration pipes; the refrigeration compressor provides cooling capacity to the refrigerant inside the refrigeration pipes.

[0054] A second temperature sensor is installed at the tube-side outlet of the secondary condenser; the second temperature sensor is used to measure the temperature at the tube-side outlet of the secondary condenser and send the data to the PLC;

[0055] A differential pressure sensor is installed between the tube-side outlet and the tube-side inlet of the secondary condenser; the differential pressure sensor is used to measure the pressure drop on the tube side of the secondary condenser and send the data to the PLC;

[0056] The PLC is also used to adjust the refrigeration power of the refrigeration compressor by adjusting the frequency of the refrigeration compressor inverter based on the difference between the measured value and the set value of the secondary condenser tube-side outlet temperature, so as to maintain the secondary condenser tube-side outlet temperature at the set value; and to adjust the refrigeration power of the refrigeration compressor by adjusting the frequency of the refrigeration compressor inverter based on the difference between the measured value and the set value of the secondary condenser tube-side pressure drop, so as to maintain the secondary condenser tube-side pressure drop at the set value.

[0057] In this invention, as one possible implementation, the demister is a container filled with a hydrophilic material, including but not limited to a container filled with a ceramic corrugated material. The hydrophilic material has a large specific surface area, enabling it to adhere to the surface of fine droplets in the humid gas, agglomerating them into larger droplets for removal in subsequent processes. This achieves the technical effect of completely separating droplets entrained in the humid gas, preventing the droplets from re-vaporizing during reheating and thus increasing the moisture content of the obtained dry gas.

[0058] In this invention, as one possible implementation method, both the primary separator and the secondary separator are gas-liquid separation devices, including but not limited to cyclone separators.

[0059] The present invention also provides a low-temperature gas dehumidification process, which uses the above-mentioned low-temperature gas dehumidification device and includes the following steps:

[0060] Moist gas is fed into the tube side of the first-stage condenser through the tube-side inlet, and the cooling medium is fed into the shell side of the first-stage condenser through the shell-side inlet. The moist gas on the tube side of the first-stage condenser exchanges heat with the cooling medium on the shell side of the first-stage condenser. The moist gas is condensed in the first stage, and the cooling medium is heated. The moist gas after condensation in the first stage is sent into the first-stage separator from the tube-side outlet of the first-stage condenser through the inlet of the first-stage separator. The heated cooling medium is sent into the shell side of the regenerator from the shell-side outlet of the first-stage condenser through the shell-side inlet of the regenerator.

[0061] The primary separator performs primary separation on the wet gas after primary condensation. The liquid after primary separation is discharged from the bottom outlet of the primary separator, and the wet gas after primary separation is sent into the tube side of the secondary condenser from the top outlet of the primary separator through the tube side inlet of the secondary condenser.

[0062] The wet gas after primary separation flows through the heat exchange tube bundle of the secondary condenser. The refrigerant in the refrigeration tubes outside the shell of the secondary condenser transfers its cooling capacity to the heat exchange medium through the shell. The heat exchange medium then transfers its cooling capacity to the wet gas after primary separation through the heat exchange tube bundle, thus performing secondary condensation on the wet gas after primary separation. The wet gas after secondary condensation is then sent to the demister from the tube-side outlet of the secondary condenser through the demister inlet.

[0063] The demister removes condensation from the humid gas after secondary condensation, eliminating fine droplets; the demisted humid gas is then fed into the secondary separator from the demister outlet through the secondary separator inlet.

[0064] The secondary separator performs secondary separation on the defoamed wet gas. The liquid after secondary separation is discharged through the bottom outlet of the secondary separator, and the dry gas after secondary separation is sent into the tube side of the regenerator from the top outlet of the secondary separator through the tube side inlet of the regenerator.

[0065] The dry gas on the tube side of the regenerator exchanges heat with the cooling medium on the shell side of the regenerator. The dry gas is reheated and the cooling medium is cooled. The reheated dry gas is discharged through the tube side outlet of the regenerator, and the cooled medium is discharged through the shell side outlet of the regenerator.

[0066] The primary condenser serves two purposes: first, to perform preliminary condensation of the humid gas, condensing some of the moisture in the humid gas into liquid, so as to reduce the energy consumption of subsequent processes; second, to raise the temperature of the cooling medium to a preset range, so as to serve as a heat source for the subsequent reheating of dry gas.

[0067] The purpose of using a heat exchange medium is to maintain the temperature of the cold source of the secondary condenser by utilizing the relatively large specific heat of the heat exchange medium, so that the cooling temperature of the wet gas is kept in a relatively stable range, even when the flow rate of the wet gas changes.

[0068] In one possible implementation of this invention, during the primary condensation of humid gas, a first temperature sensor measures the shell-side outlet temperature of the primary condenser and sends it to a PLC controller; the PLC controller adjusts the opening of the regulating valve based on the difference between the measured value and the set value of the shell-side outlet temperature of the primary condenser, so as to maintain the shell-side outlet temperature of the primary condenser at the set value.

[0069] When the measured pressure drop on the tube side of the secondary condenser is higher than the set value, it indicates that the refrigeration power of the compressor is too high, and the humid gas on the tube side of the secondary condenser will freeze. Similarly, when the temperature of the humid gas at the tube side outlet of the secondary condenser is lower than 0°C, it indicates that the refrigeration power of the compressor is too high, and the humid gas on the tube side of the secondary condenser will freeze. To prevent freezing of the humid gas on the tube side of the secondary condenser, in this invention, as one possible implementation, during the secondary condensation of the humid gas, a second temperature sensor measures the outlet temperature on the tube side of the secondary condenser and sends it to the PLC, and a differential pressure sensor measures the pressure drop on the tube side of the secondary condenser and sends it to the PLC. Based on the difference between the measured and set values ​​of the outlet temperature on the tube side of the secondary condenser, the PLC adjusts the refrigeration power of the compressor by adjusting the frequency of the compressor inverter to maintain the outlet temperature on the tube side of the secondary condenser at the set value. Similarly, based on the difference between the measured and set values ​​of the pressure drop on the tube side of the secondary condenser, the PLC adjusts the refrigeration power of the compressor by adjusting the frequency of the compressor inverter to maintain the pressure difference between the inlet and outlet of the tube side of the secondary condenser at the set value.

[0070] When the measured pressure drop on the tube side of the secondary condenser is higher than a certain set value, the PLC reduces the frequency of the refrigeration compressor inverter to reduce the refrigeration power of the refrigeration compressor inverter, so as to maintain the pressure drop on the tube side of the secondary condenser at the set value.

[0071] When the measured temperature at the tube-side outlet of the secondary condenser is higher than 0°C, the PLC increases the frequency of the refrigeration compressor inverter to increase its cooling power, thereby maintaining the tube-side outlet temperature of the secondary condenser at the set value.

[0072] In this invention, as one possible implementation method, the cooling medium includes, but is not limited to, cooling water and air.

[0073] Example 1

[0074] See Figure 2-5 The gas low-temperature dehumidification device and process of this embodiment are used for dehumidification before sampling and analysis of the gas blown out of the boiler feedwater of a power plant, so as to protect the sampling device; the humid gas entering the first-stage condenser is the boiler feedwater blown out gas; the reheated dry gas is discharged to the sampling device through the tube-side outlet of the regenerator for sampling and analysis.

[0075] See Figure 6 Low-pressure steam enters the deaerator and mixes evenly with the boiler feedwater inside, creating bubbles that blow out dissolved air from the boiler feedwater, resulting in boiler feedwater blow-out gas. This boiler feedwater blow-out gas is a mixture of air and water vapor at a temperature above 100°C. To protect the sampling device, the boiler feedwater blow-out gas needs to be cooled before entering the sampling device, and most of the water vapor needs to be removed, ensuring that the relative humidity of the boiler feedwater blow-out gas entering the sampling device is below 50% and the temperature is close to room temperature. The power for the flow of the boiler feedwater blow-out gas is provided by a vacuum pump.

[0076] In this embodiment, the heat exchange medium is ethylene glycol and the cooling medium is cooling water.

[0077] In this embodiment, the set value of the pressure drop on the tube side of the secondary condenser is 0.35 kPa; the set value of the outlet temperature on the tube side of the secondary condenser is 1°C; when the measured value of the pressure drop on the tube side of the secondary condenser is higher than 2 kPa, the PLC reduces the refrigeration power of the refrigeration compressor to maintain the pressure drop on the tube side of the secondary condenser at the set value; when the measured value of the outlet temperature on the tube side of the secondary condenser is higher than 0°C, the PLC increases the refrigeration power of the refrigeration compressor to maintain the outlet temperature on the tube side of the secondary condenser at the set value.

[0078] See Figure 7 This embodiment records the tube-side pressure drop and tube-side outlet temperature of the secondary condenser over 8 hours. Tests show that the advantage of the secondary condenser adjustment method is that it can achieve a lower cooling temperature, thus providing better dehumidification performance compared to existing low-temperature gas dehumidification processes.

[0079] In this embodiment, the process parameters for low-temperature gas dehumidification are shown in Table 1.

[0080] Table 1. Gas low-temperature dehumidification process parameters in this embodiment

[0081]

[0082]

[0083] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A gas dehumidification device, characterized in that, It includes a primary condenser, a primary separator, a secondary condenser, a secondary separator, a demister, a regenerator, and a PLC controller; the shell-side outlet of the primary condenser is connected to the shell-side inlet pipeline of the regenerator; the tube-side outlet of the primary condenser is connected to the inlet pipeline of the primary separator; the top outlet of the primary separator is connected to the tube-side inlet of the secondary condenser; the tube-side outlet of the secondary condenser is connected to the inlet pipeline of the demister; the outlet of the demister is connected to the inlet pipeline of the secondary separator; and the top outlet of the secondary separator is connected to the tube-side inlet pipeline of the regenerator. The secondary condenser is a heat exchanger with a heat exchange medium. The heat exchange tube bundle in the secondary condenser is immersed in the heat exchange medium. The heat exchange medium is a liquid that does not solidify or vaporize at the process temperature. The shell of the secondary condenser is wrapped with refrigeration pipes, and refrigerant is contained inside the refrigeration pipes; the refrigeration compressor provides cooling capacity to the refrigerant inside the refrigeration pipes. A second temperature sensor is installed at the tube-side outlet of the secondary condenser; the second temperature sensor is used to measure the temperature at the tube-side outlet of the secondary condenser and send the data to the PLC; A differential pressure sensor is installed between the tube-side outlet and the tube-side inlet of the secondary condenser; the differential pressure sensor is used to measure the pressure drop on the tube side of the secondary condenser and send the data to the PLC; The PLC is used to adjust the refrigeration power of the refrigeration compressor based on the difference between the measured value and the set value of the outlet temperature on the tube side of the secondary condenser, so as to maintain the outlet temperature on the tube side of the secondary condenser at the set value; and to adjust the refrigeration power of the refrigeration compressor based on the difference between the measured value and the set value of the pressure drop on the tube side of the secondary condenser, so as to maintain the pressure drop on the tube side of the secondary condenser at the set value.

2. The gas dehumidification device according to claim 1, characterized in that, A regulating valve is provided at the shell-side inlet of the first-stage condenser, and a first temperature sensor is provided at the shell-side outlet of the first-stage condenser. The first temperature sensor is used to measure the shell-side outlet temperature of the first-stage condenser and send it to the PLC controller. The PLC controller is also used to adjust the opening of the regulating valve based on the difference between the measured value and the set value of the primary condenser shell-side outlet temperature, so as to maintain the primary condenser shell-side outlet temperature at the set value.

3. The gas dehumidification device according to claim 1, characterized in that, The heat exchange medium is at least one of ethylene glycol, methanol, and ethanol, or a mixture of at least one of ethylene glycol, methanol, and ethanol with water, or an aqueous solution of an inorganic salt of at least one of ethylene glycol, methanol, and ethanol.

4. The gas dehumidification device according to claim 1, characterized in that, A demister is a container filled with a hydrophilic material.

5. The gas dehumidification device according to claim 1, characterized in that, Both the primary and secondary separators are gas-liquid separation devices.

6. A gas dehumidification process, characterized in that, Using the gas dehumidification device according to any one of claims 1-5 includes the following steps: Moist gas is fed into the tube side of the first-stage condenser through the tube-side inlet, and the cooling medium is fed into the shell side of the first-stage condenser through the shell-side inlet. The moist gas on the tube side of the first-stage condenser exchanges heat with the cooling medium on the shell side of the first-stage condenser. The moist gas is condensed in the first stage, and the cooling medium is heated. The moist gas after condensation in the first stage is sent into the first-stage separator from the tube-side outlet of the first-stage condenser through the inlet of the first-stage separator. The heated cooling medium is sent into the shell side of the regenerator from the shell-side outlet of the first-stage condenser through the shell-side inlet of the regenerator. The primary separator performs primary separation on the wet gas after primary condensation. The liquid after primary separation is discharged from the bottom outlet of the primary separator, and the wet gas after primary separation is sent into the tube side of the secondary condenser from the top outlet of the primary separator through the tube side inlet of the secondary condenser. The secondary condenser performs secondary condensation on the wet gas separated in the primary stage; the wet gas after secondary condensation is sent into the demister from the tube-side outlet of the secondary condenser through the demister inlet. The demister removes condensation from the humid gas after secondary condensation; the humid gas after demistering is sent from the demister outlet to the secondary separator inlet via the secondary separator inlet. The secondary separator performs secondary separation on the defoamed wet gas. The liquid after secondary separation is discharged through the bottom outlet of the secondary separator, and the dry gas after secondary separation is sent into the tube side of the regenerator from the top outlet of the secondary separator through the tube side inlet of the regenerator. The dry gas on the tube side of the regenerator exchanges heat with the cooling medium on the shell side of the regenerator. The dry gas is reheated and the cooling medium is cooled. The reheated dry gas is discharged through the tube side outlet of the regenerator, and the cooled medium is discharged through the shell side outlet of the regenerator.

7. The gas dehumidification process according to claim 6, characterized in that, During the primary condensation of wet gas, the first temperature sensor measures the shell-side outlet temperature of the primary condenser and sends it to the PLC controller. The PLC controller adjusts the opening of the regulating valve based on the difference between the measured value and the set value of the shell-side outlet temperature of the primary condenser to maintain the shell-side outlet temperature of the primary condenser at the set value.

8. The gas dehumidification process according to claim 6, characterized in that, During the two-stage condensation of wet gas, a second temperature sensor measures the outlet temperature of the second-stage condenser tube side and sends the data to the PLC. A differential pressure sensor measures the pressure drop across the second-stage condenser tube side and sends the data to the PLC. The PLC adjusts the refrigeration power of the compressor based on the difference between the measured and set values ​​of the outlet temperature of the second-stage condenser tube side to maintain the outlet temperature of the second-stage condenser tube side at the set value. The PLC also adjusts the refrigeration power of the compressor based on the difference between the measured and set values ​​of the pressure drop across the second-stage condenser tube side to maintain the pressure difference between the inlet and outlet of the second-stage condenser tube side at the set value. When the measured pressure drop on the tube side of the secondary condenser is higher than the set value, the humid gas on the tube side of the secondary condenser will freeze; when the measured outlet temperature on the tube side of the secondary condenser is lower than 0°C, the humid gas on the tube side of the secondary condenser will freeze. When the measured pressure drop on the tube side of the secondary condenser exceeds a certain set value, the PLC reduces the refrigeration power of the refrigeration compressor inverter to maintain the pressure drop on the tube side of the secondary condenser within the set value. When the measured temperature at the tube-side outlet of the secondary condenser is higher than 0°C, the PLC increases the refrigeration power of the refrigeration compressor to maintain the tube-side outlet temperature at the set value.

9. The gas dehumidification process according to claim 8, characterized in that, The humid gas entering the first-stage condenser is the gas blown out by the boiler feedwater. The set value for the pressure drop on the tube side of the secondary condenser is 0.35 kPa; the set value for the outlet temperature on the tube side of the secondary condenser is 1 °C. When the measured pressure drop on the tube side of the secondary condenser is higher than 2 kPa, the PLC reduces the refrigeration power of the refrigeration compressor to maintain the pressure drop on the tube side of the secondary condenser at the set value. When the measured temperature at the tube-side outlet of the secondary condenser is higher than 0°C, the PLC increases the refrigeration power of the refrigeration compressor to maintain the tube-side outlet temperature at the set value.

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