Low-temperature permeation trap for online monitoring of greenhouse gas

Abstract

The utility model relates to the technical field of measurement and testing, and discloses a low-temperature permeation trap for greenhouse gas on-line monitoring, which comprises a low-temperature trap shell, a refrigeration module and a sample gas treatment device, and the refrigeration module comprises a compressor, a radiator, an evaporator, an expansion valve and a drying pipe which are sleeved in the low-temperature trap shell. The compressor and the expansion valve, the expansion valve and the radiator, the radiator and the drying pipe, the drying pipe and the evaporator, and the evaporator and the compressor are communicated through pipelines to form a closed-loop cooling system, and the sample gas treatment device comprises a sample gas treatment shell sleeved in the rear end of the low-temperature trap shell; and the middle part of the evaporator is sleeved in the sample gas treatment shell. The low-temperature permeation trap for greenhouse gas on-line monitoring provided by the utility model is simple and reasonable in structural design, and the water removal effect and flexible regulation and control can be effectively realized through continuous cooperative operation of the water molecule exchange membrane assembly and the refrigeration module.

Description

Technical Field

[0001] This utility model relates to the field of measurement and testing technology, specifically a low-temperature permeation trap for online monitoring of greenhouse gases. Background Technology

[0002] Gas analyzers designed based on infrared spectroscopy principles are highly sensitive to water vapor concentration in samples. Water vapor concentration absorbs infrared light, thus affecting the accuracy of the analyzer's results. Therefore, according to relevant national regulations, when using such analyzers to monitor greenhouse gases (such as CO2 and CH4), a dehumidification device needs to be installed to reduce the water vapor concentration in the sample gas to within the required range.

[0003] Existing sample gas dehydration technologies can be broadly categorized into two types. One type employs a cold trap, where the sampling system consists of a sampling tower, sampling pipe, primary dehydration equipment, a cryogenic cold trap device, a sampling pump, a flow and pressure control module, and a calibration module.

[0004] The second type is a semi-permeable membrane technology solution. The sampling system consists of a sampling tower, sampling tube, primary water removal equipment, semi-permeable membrane water removal device, sampling pump, flow and pressure control module, calibration module, etc.

[0005] Both of these technical solutions have some drawbacks in practical use:

[0006] The design of cryogenic cold trap devices is generally derived from laboratory equipment condenser tubes. Due to the large volume of the condenser tubes, the overall volume of the cold trap is also large, resulting in a slow gas replacement rate. Furthermore, using a cold trap requires regular defrosting and de-icing; otherwise, the interior of the cold trap will become blocked. Using a single condenser tube requires interrupting sampling for defrosting; using two condenser tubes requires alternating operation for heating and defrosting. The dead volume in the pipeline during the alternating gas path switching of the condenser tubes affects the sample gas, with the larger the condenser tube volume, the greater the impact. To minimize this impact, some solenoid valves are required, along with programmed control, making the entire system relatively complex and costly.

[0007] The technical solution using a semi-permeable membrane dehydration device has the disadvantage that it can only dry the gas to a dew point temperature of approximately -45 to -30°C, corresponding to a water vapor concentration of around 376 ppm. The dehydration effect is far lower than that of a cryogenic cold trap. Utility Model Content

[0008] To address the shortcomings of existing technologies, this invention provides a low-temperature infiltration trap for online monitoring of greenhouse gases, thus solving the problems mentioned in the background section.

[0009] This utility model provides the following technical solution: a low-temperature infiltration trap for online monitoring of greenhouse gases, comprising a low-temperature trap shell, a refrigeration module, and a sample gas processing device. The refrigeration module includes a compressor, a radiator, an evaporator, an expansion valve, and a drying pipe, all housed inside the low-temperature trap shell. The compressor and the expansion valve, the expansion valve and the radiator, the radiator and the drying pipe, the drying pipe and the evaporator, and the evaporator and the compressor are all connected by pipelines to form a closed-loop cooling system.

[0010] The sample gas processing device includes a sample gas processing shell fitted inside the rear end of the cryogenic trap shell. The middle part of the evaporator is fitted inside the sample gas processing shell, and the circulating folded copper tube structure in the middle of the evaporator forms a sample gas processing chamber inside the sample gas processing shell. A water molecule exchange membrane assembly is fitted inside the sample gas processing shell, and the water molecule exchange membrane assembly can divide the internal space of the sample gas processing chamber into an inner processing space and an outer processing space. Four fluid pipeline interfaces are installed at the rear end of the cryogenic trap shell, and two of the fluid pipeline interfaces are connected to the inner processing space, and the other two fluid pipeline interfaces are correspondingly connected to the outer processing space.

[0011] Preferably, thermal insulation cotton is installed between the surface of the middle part of the evaporator and the inner wall of the sample gas treatment shell.

[0012] Preferably, the output end of the compressor is connected to the input end of the expansion valve, the output end of the expansion valve is connected to the input end of the radiator, the output end of the radiator is connected to the input end of the evaporator, and the output end of the evaporator is connected to the input end of the compressor via conduits.

[0013] Preferably, a 1 / 8 or 1 / 4 stainless steel threaded ferrule is provided between the end of the conduit and the port of the corresponding device.

[0014] Preferably, the water molecule exchange membrane assembly consists of a support panel and a water molecule exchange membrane nested and fixed inside the support panel, and the support panel is nested inside the sample gas treatment shell, and the water molecule exchange membrane is made of hollow glass fiber.

[0015] Preferably, the inner wall of the bottom of the cryogenic trap housing is provided with a threaded hole, and the bottom structure of the sample gas treatment housing is provided with a clearance hole that can be aligned with the threaded hole. The bottom structure of the sample gas treatment housing and the bottom inner wall of the cryogenic trap housing can be detachably installed by means of screws fitting into the clearance hole and then screwing them into the threaded hole.

[0016] Preferably, a temperature sensor is installed inside the cryogenic trap housing, and the detection end of the temperature sensor extends into the interior of the sample gas processing housing, and the temperature sensor has a data output function.

[0017] Preferably, the bottom of the radiator is provided with a water tray, and the front end of the low temperature trap housing is equipped with a fan facing the water tray.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention provides a low-temperature permeation trap for online monitoring of greenhouse gases. The structure is simple and reasonable, and through the continuous cooperation of the water molecule exchange membrane component and the refrigeration module, it can effectively remove water and flexibly control the operation.

[0020] 2. The low-temperature permeation trap provided by this utility model for online monitoring of greenhouse gases is conducive to rapid gas replacement and rapid response, and achieves technical effects such as low gas dew point and low water vapor concentration after treatment. It is suitable for water removal treatment before high-precision monitoring of room temperature gases. The technical method has a simple structure, does not require complex control circuits, and is easy to disassemble and install, which helps to improve the maintenance efficiency of the water removal system. Attached Figure Description

[0021] Figure 1 This is a cross-sectional schematic diagram of the cryogenic trap shell of this utility model.

[0022] Figure 2 This is a three-dimensional schematic diagram of the structure of this utility model;

[0023] Figure 3 This is a three-dimensional schematic diagram of the compressor structure of this utility model;

[0024] Figure 4 This is a three-dimensional schematic diagram of the heat sink structure of this utility model;

[0025] Figure 5 This is a three-dimensional schematic diagram of the evaporator structure of this utility model;

[0026] Figure 6 This is a three-dimensional schematic diagram of the expansion valve structure of this utility model;

[0027] Figure 7 This is a three-dimensional schematic diagram of the drying tube structure of this utility model;

[0028] Figure 8 This is an enlarged schematic diagram of the water molecule exchange membrane assembly of this utility model.

[0029] In the figure: 1. Low temperature trap housing; 2. Compressor; 3. Radiator; 4. Evaporator; 5. Expansion valve; 6. Drying tube; 7. Fluid pipeline interface; 8. Sample gas treatment housing; 9. Water molecule exchange membrane assembly; 91. Support panel; 92. Water molecule exchange membrane; 10. Temperature sensor. Detailed Implementation

[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0031] Please see Figure 1-8 A low-temperature infiltration trap for online monitoring of greenhouse gases includes a low-temperature trap shell 1, a refrigeration module and a sample gas processing device. The refrigeration module includes a compressor 2, a radiator 3, an evaporator 4, an expansion valve 5 and a drying pipe 6, which are installed inside the low-temperature trap shell 1. The compressor 2 and the expansion valve 5, the expansion valve 5 and the radiator 3, the radiator 3 and the drying pipe 6, the drying pipe 6 and the evaporator 4, and the evaporator 4 and the compressor 2 are all connected by pipelines to form a closed-loop cooling system.

[0032] The output end of compressor 2 is connected to the input end of expansion valve 5, the output end of expansion valve 5 is connected to the input end of radiator 3, the output end of radiator 3 is connected to the input end of evaporator 4, and the output end of evaporator 4 is connected to the input end of compressor 2 through conduits.

[0033] The sample gas processing device includes a sample gas processing housing 8 fitted inside the rear end of the cryogenic trap housing 1. The middle part of the evaporator 4 is fitted inside the sample gas processing housing 8, and the circulating folded copper tube structure in the middle of the evaporator 4 forms a sample gas processing chamber inside the sample gas processing housing 8. A water molecule exchange membrane assembly 9 is fitted inside the sample gas processing housing 8. The water molecule exchange membrane assembly 9 consists of a support panel 91 and a water molecule exchange membrane 92 nested and fixed inside the support panel 91. The support panel 91 is nested inside the sample gas processing housing 8. The water molecule exchange membrane 92 is made of hollow glass fiber, and the water molecule exchange membrane assembly 9 can divide the internal space of the sample gas processing chamber into an inner processing space and an outer processing space. Four fluid pipeline interfaces 7 are installed at the rear end of the cryogenic trap housing 1, and two of the fluid pipeline interfaces 7 are connected to the inner processing space, and the other two fluid pipeline interfaces 7 are correspondingly connected to the outer processing space.

[0034] During use, the sample gas and the dry air that provides the power for water molecule exchange are introduced and drawn out through the two fluid pipe interfaces 7 at the rear end of the low temperature trap shell 1. In the specific process, the refrigerant output by the compressor 2 enters the drying pipe 6 after heat exchange through the radiator 3. After dust removal and drying, the drying pipe 6 is connected to the conduit and transported to the evaporator 4. The evaporator 4 provides a continuous cold source for the sample gas processing chamber. After heat exchange, the refrigerant flows back to the compressor 2 at low pressure. The expansion valve 5 is connected in series to the high pressure pipeline installed in the compressor 2, which can adjust the refrigerant supply and stabilize the temperature at the set value.

[0035] In the specific cooling process, the humid air sample and the dry air are respectively guided to the inner processing space and the outer processing space through their respective fluid pipeline interfaces 7, which also serve as inputs. Since the water molecule exchange membrane 92 is a non-porous membrane, almost no gas components other than water vapor can pass through it, and the water vapor will move from the humid side to the dry side through the water molecule exchange membrane 92, thereby obtaining dehumidified gas.

[0036] Experiments revealed that the temperature inside the sample gas treatment housing 8 also affects the drying capacity. The gas inside the sample gas treatment housing 8 has a lower dew point due to the low temperature, meaning the gas becomes drier due to the low temperature. Through experiments, when the dew point of the dried air on the outside is -60℃, and a more humid gas with a dew point of -30℃ is introduced into the inside, with the cooling temperature set between -13℃ and -24℃, the dew point of the dried air will be between -45℃ and -65℃, and the water vapor concentration will be between 0.006% and 0.0004%.

[0037] Please see Figure 1 , Figure 5 Insulation cotton is installed between the surface of the middle part of the evaporator 4 and the inner wall of the sample gas treatment shell 8. A 1 / 8 or 1 / 4 stainless steel threaded sleeve is provided between the end of the conduit and the port of the corresponding equipment, which helps to improve the applicability of the overall open structure connection of the equipment.

[0038] The inner wall of the bottom of the cryogenic trap housing 1 is provided with a threaded hole, and the bottom structure of the sample gas treatment housing 8 is provided with a clearance hole that can be aligned with the threaded hole. The bottom structure of 81 and the bottom inner wall of the cryogenic trap housing 1 can be detached and installed by means of screws and clearance hole fittings and screw locking with the threaded hole.

[0039] When in use, for subsequent maintenance and replacement of the water molecule exchange membrane assembly 9 and the evaporator 4, the screws connecting the bottom of the sample gas treatment housing 8 and the bottom inner wall of the low temperature trap housing 1 can be directly removed. After that, the water molecule exchange membrane assembly 9, the evaporator 4 and the sample gas treatment housing 8 can be disassembled as a whole to meet the module replacement requirements.

[0040] Please see Figure 1 A temperature sensor 10 is installed inside the low-temperature trap housing 1, and the detection end of the temperature sensor 10 extends into the sample gas processing housing 8. The temperature sensor 10 has a data output function. A water tray is provided at the bottom of the heat sink 3, and a fan facing the water tray is installed at the front end of the low-temperature trap housing 1.

[0041] Working principle: When in use, the temperature sensor 10 can be a RS485 temperature sensor, and the real-time temperature signal inside the sample gas processing housing 8 is output via RS485, which facilitates quick connection with other data acquisition systems. It is equipped with a water collection tray to collect condensate and two sets of fans to blow and evaporate it, thereby ensuring that no condensate flows out of the entire device.

[0042] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Additionally, in the accompanying drawings of this utility model, the fill patterns are merely for distinguishing layers and do not constitute any other limitation.

[0043] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A cryogenic infiltration trap for online monitoring of greenhouse gases, comprising a cryogenic trap shell (1), a refrigeration module, and a sample gas processing device, characterized in that: The refrigeration module includes a compressor (2), a radiator (3), an evaporator (4), an expansion valve (5), and a drying pipe (6) installed inside the low-temperature trap shell (1). The compressor (2) and the expansion valve (5), the expansion valve (5) and the radiator (3), the radiator (3) and the drying pipe (6), the drying pipe (6) and the evaporator (4), and the evaporator (4) and the compressor (2) are all connected by pipelines to form a closed-loop cooling system. The sample gas processing device includes a sample gas processing housing (8) fitted inside the rear end of the low-temperature trap housing (1). The middle part of the evaporator (4) is fitted inside the sample gas processing housing (8), and the copper tube structure in the middle of the evaporator (4) forms a sample gas processing chamber inside the sample gas processing housing (8). A water molecule exchange membrane assembly (9) is fitted inside the sample gas processing housing (8), and the water molecule exchange membrane assembly (9) can divide the internal space of the sample gas processing chamber into an inner processing space and an outer processing space. Four fluid pipeline interfaces (7) are installed at the rear end of the low-temperature trap housing (1), and two of the fluid pipeline interfaces (7) are connected to the inner processing space, and the other two fluid pipeline interfaces (7) are connected to the outer processing space.

2. The cryogenic infiltration trap for online monitoring of greenhouse gases according to claim 1, characterized in that: Insulating cotton is installed between the surface of the middle part of the evaporator (4) and the inner wall of the sample gas treatment shell (8).

3. A cryogenic infiltration trap for online monitoring of greenhouse gases according to claim 1, characterized in that: The output end of the compressor (2) is connected to the input end of the expansion valve (5), the output end of the expansion valve (5) is connected to the input end of the radiator (3), the output end of the radiator (3) is connected to the input end of the evaporator (4), and the output end of the evaporator (4) is connected to the input end of the compressor (2) through conduits.

4. A cryogenic infiltration trap for online monitoring of greenhouse gases according to claim 3, characterized in that: A 1 / 8 or 1 / 4 stainless steel threaded ferrule is provided between the end of the conduit and the port of the corresponding device.

5. A cryogenic infiltration trap for online monitoring of greenhouse gases according to claim 1, characterized in that: The water molecule exchange membrane assembly (9) consists of a support panel (91) and a water molecule exchange membrane (92) nested and fixed inside the support panel (91). The support panel (91) is nested inside the sample gas treatment housing (8). The water molecule exchange membrane (92) is made of hollow glass fiber.

6. A cryogenic infiltration trap for online monitoring of greenhouse gases according to claim 1, characterized in that: The inner wall of the bottom of the cryogenic trap housing (1) is provided with a threaded hole, and the bottom structure of the sample gas treatment housing (8) is provided with a clearance hole that can be aligned with the threaded hole. The bottom structure of (81) and the bottom inner wall of the cryogenic trap housing (1) can be detached and installed by means of screws and clearance hole fitting and screw locking with the threaded hole.

7. A cryogenic infiltration trap for online monitoring of greenhouse gases according to claim 1, characterized in that: The temperature sensor (10) is installed inside the low-temperature trap housing (1), and the detection end of the temperature sensor (10) extends into the sample gas processing housing (8), and the temperature sensor (10) has a data output function.

8. A cryogenic infiltration trap for online monitoring of greenhouse gases according to claim 1, characterized in that: The bottom of the radiator (3) is provided with a water tray, and the front end of the low temperature trap housing (1) is equipped with a fan facing the water tray.

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