Low-temperature cold trap water removal device

Abstract

The invention discloses a low-temperature cold trap water removal device which comprises more than two water removal channels which are connected in parallel; each water removal channel comprises a refrigeration water removal gas path and an ice melting purging gas path which are connected in series; each refrigeration and water removal gas path is also connected with an inlet of a dry gas collection gas path, and an outlet of the dry gas collection gas path is used for being connected with an analyzer; and each water removal channel is connected with a controller, and the controller is used for controlling the refrigeration water removal gas paths and the ice melting purging gas paths of the different water removal channels to operate in a staggered mode. According to the application, moisture in the gas to be dewatered can be effectively removed, frost can be timely removed, and related phenomena such as relatively large dead volume of the cold trap can be avoided.

Description

Technical Field

[0001] The present application relates to the technical field of cold traps, and in particular to a low-temperature cold trap water removal device. Background Art

[0002] Accurately carrying out carbon dioxide and other greenhouse gas monitoring and obtaining the long-term changing trends of carbon dioxide and other greenhouse gas concentrations in my country are the basis for in-depth research on climate change.

[0003] Existing technologies for analyzing atmospheric greenhouse gas concentrations typically use specialized gas analyzers. These measurement systems accurately determine the composition and concentration of these gases. However, because ambient gases contain a certain amount of moisture, this presence can cause deviations in gas concentration measurements. Therefore, prior to gas analysis, pretreatment of the gas to be analyzed is necessary to remove moisture and improve analysis accuracy.

[0004] For greenhouse gas pretreatment, the main water removal methods currently used in cold traps are semiconductor refrigeration or liquid nitrogen / liquid oxygen refrigeration. The former can only reach a minimum refrigeration temperature of -40°C, resulting in poor water removal effectiveness; the latter wastes liquid nitrogen / liquid oxygen, is difficult to operate, and carries the risk of frostbite. Furthermore, the current large dead volume of cold traps results in long flushing times when switching between cold trap channels and between standard and sample gases, affecting accurate gas measurement. Furthermore, water vapor is prone to significant fluctuations during channel switching. Summary of the Invention

[0005] The purpose of this application is to provide a low-temperature cold trap water removal device to solve the above technical problems.

[0006] To achieve the above-mentioned purpose, the low-temperature cold trap dewatering device provided in the embodiment of the present application includes: two or more dewatering channels, each of the dewatering channels being connected in parallel; Each of the dehydration channels includes a refrigeration dehydration gas circuit and an ice melting and purge gas circuit connected in series; each of the refrigeration dehydration gas circuits is also connected to the inlet of the dry gas collection gas circuit, and the outlet of the dry gas collection gas circuit is used to connect to the analyzer; Each of the dewatering channels is connected to a controller, and the controller is used to control the staggered operation of the refrigeration dewatering air path and the ice melting and purge air path of different dewatering channels.

[0007] Furthermore, each of the water removal channels receives the gas to be dehydrated through a first solenoid valve, each first solenoid valve has an inlet and at least two outlets, and the first solenoid valve is connected to the controller and adjusts the opening and closing of the outlet according to the control instructions of the controller.

[0008] Furthermore, the first solenoid valve is connected to the gas containing bottle to be dehydrated through a valve and an air pump in sequence.

[0009] Furthermore, each of the refrigeration and dehumidification gas circuits includes a second solenoid valve and a cooling coil, wherein the inlet of the second solenoid valve is connected to the outlet of the first solenoid valve, and the outlet of the second solenoid valve is connected to the cooling coil, and the cooling coil obtains dry gas by condensing the moisture in the gas to be dehydrated into solid frost.

[0010] Furthermore, a cold trap pool is provided at the position of the cooling coil, and a refrigerant is provided in the cold trap pool. The refrigerant serves as an intermediate conduction medium to conduct temperature to the cooling coil immersed therein. After the temperature of the cooling coil is assimilated to -78°C, the water vapor in the gas to be dehydrated condenses and the gas becomes a dry gas. A compressor is also provided at the position of the cold trap pool, and the compressor is used for refrigeration to take away the heat in the refrigerant.

[0011] Furthermore, the cooling coil is connected to a robotic arm, and the robotic arm is connected to the controller. The controller controls the cooling coil to be located below or above the refrigerant liquid level through the robotic arm according to the current operating status.

[0012] Furthermore, each of the ice-melting purge air paths includes a purge pump, a heating pipe, and a third solenoid valve; The purge pump is arranged at a high position relative to the cooling coil to form a top-down purge. The purge pump inlet is used to inhale ambient air, and the purge pump outlet is connected to the heating pipe inlet. The heating pipe has more than two outlets, and each heating pipe outlet is connected to a cooling coil of the refrigeration and dehumidification gas circuit through a third solenoid valve.

[0013] Furthermore, each of the dry gas collection gas lines includes a fourth solenoid valve, the inlet of the fourth solenoid valve is connected to the dry gas outlet of the cooling coil through the third solenoid valve, and the outlets of all the fourth solenoid valves are connected to the analyzer inlet through pipelines.

[0014] Furthermore, all the water removal channels are arranged in a chassis, and a fan is also arranged in the chassis.

[0015] Furthermore, the chassis includes a back panel and side panels, the back panel is provided with a window for interacting with the outside world, and the side panels are provided with louver-shaped air inlets.

[0016] Compared with the prior art, the low-temperature cold trap water removal device provided in the embodiment of the present application has at least the following advantages: The embodiment of the present application controls the staggered operation of the refrigeration and dehydration air paths and the ice-melting and purge air paths of different dehydration channels, which not only enables the refrigeration and dehydration air paths or the ice-melting and purge air paths of each dehydration channel to work in turn without interfering with each other, thereby effectively improving the dehydration effect, but also can timely remove frost through the ice-melting and purge air paths, thereby avoiding the large dead volume of the cold trap, which leads to long flushing time when switching the cold trap channel and switching the standard gas / sample gas, and large water vapor fluctuations when switching the channels, thereby ensuring accurate measurement of the gas.

[0017] The low-temperature cold trap dehydration device provided in the embodiment of the present application realizes effective dehydration of sample gas and / or standard gas through mutual cooperation between various levels, so that the water vapor content can be reduced to below 50 ppm. Therefore, it can be widely used in the field of gas dehydration technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the gas path structure of the low-temperature cold trap water removal device provided in an embodiment of the present application.

[0019] Figure 2 It is a schematic diagram of the rear view structure of the low-temperature cold trap water removal device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0020] The technical solutions of this application will be clearly and completely described below in conjunction with specific implementation plans. However, those skilled in the art should understand that the implementation plans described below are only used to illustrate this application and should not be considered to limit the scope of this application. Based on the implementation plans in this application, all other implementation plans obtained by those of ordinary skill in the art without making any creative efforts are within the scope of protection of this application.

[0021] like Figure 1 As shown, the low-temperature cold trap dewatering device provided in the embodiment of the present application includes: two or more dewatering channels. In this embodiment, two dewatering channels are provided, but it is not limited thereto. In actual use, they can be provided as needed, and the dewatering channels are connected in parallel; Each dehydration channel includes a refrigeration dehydration gas line 1 and an ice melting purge gas line 2 connected in series; each refrigeration dehydration gas line 1 is also connected to the inlet of a dry gas collection gas line 3, and the outlet of the dry gas collection gas line 3 is used to connect to an analyzer 4; Each dewatering channel is connected to a controller, which is used to control the staggered operation of the refrigeration dewatering air path 1 and the ice melting and purge air path 2 of different dewatering channels.

[0022] For ease of understanding, a fully automatic dual-path dual-circulation dehydration structure formed by setting up two dehydration channels is used as an example for explanation. For the convenience of description, the two dehydration channels are named A dehydration channel and B dehydration channel respectively, that is: while the refrigeration and dehydration air path 1 of the dehydration channel A is performing refrigeration and dehydration, the ice-melting and purge air path 2 of the dehydration channel B is performing ice-melting and purge; while the refrigeration and dehydration air path 1 of the dehydration channel B is performing refrigeration and dehydration, the ice-melting and purge air path 2 of the dehydration channel A is performing ice-melting and purge, thereby realizing uninterrupted refrigeration and dehydration of the gas to be dehydrated (sample gas and / or standard gas).

[0023] Of course, when multiple water removal channels are provided, a fully automatic multi-path multi-circulation water removal structure can be formed, and its operating principle is basically the same as that of the fully automatic dual-path dual-circulation water removal structure, which will not be elaborated here.

[0024] It can be seen that by controlling the staggered operation of the refrigeration and dehydration air path 1 and the ice-melting and purge air path 2 of different dehydration channels, not only the refrigeration and dehydration air path 1 or the ice-melting and purge air path 2 of each dehydration channel can work in turn without interfering with each other, thereby effectively improving the dehydration effect, but also the ice-melting and purge air path 2 can be used to clear frost in time, thereby avoiding the large dead volume of the cold trap, which leads to a long flushing time when switching the cold trap channel and the standard gas / sample gas, and a large water vapor fluctuation when switching the channel, thereby ensuring accurate measurement of the gas.

[0025] In the implementation of this application, each dewatering channel receives the gas to be dewatered through the first solenoid valve 5. The first solenoid valve 5 has an inlet and at least two outlets. The number of outlets of the first solenoid valve 5 is adaptively selected according to the number of dewatering channels, which is not limited here. The first solenoid valve 5 is connected to the controller and adjusts the switch of the outlet according to the control instructions of the controller to realize the selection of the dewatering channel.

[0026] The first solenoid valve 5 can be connected to the gas containing bottle 6 to be dehydrated through a valve and an air pump in sequence, so that the gas to be dehydrated can be sucked into the dehydration channel by the air pump.

[0027] Among them, the vacuum pump flow rate is ≥11L / min, which can enable the high tower atmosphere to reach the inside of the water removal channel from the sampling port at a faster speed.

[0028] In order to prevent excessive sample gas from entering the dehydration channel and causing a decrease in the dehydration effect, an overflow port can be set between the outlet of the vacuum pump and the inlet of the dehydration channel so that excess sample gas can be discharged from the overflow port.

[0029] Specifically, the first solenoid valve 5 can be connected to the first interface of the three-way valve, the second interface of the three-way valve is connected to the air pump, the air pump is connected to the gas holding bottle 6 to be dehydrated, and the third interface of the three-way valve is used as an overflow port for emptying.

[0030] In the implementation of this application, each refrigeration and dehydration gas circuit 1 includes a second solenoid valve 11 and a cooling coil 12, wherein the inlet of the second solenoid valve 11 is connected to the outlet of the first solenoid valve 5, and the outlet of the second solenoid valve 11 is connected to the cooling coil 12. The cooling coil 12 obtains dry gas by condensing the moisture in the gas to be dehydrated into solid frost.

[0031] The capacity of the cooling coil 12 can be set to 36 ml to reduce the dead volume, thereby further shortening the flushing time and response time caused by the switching of the cooling coil 12 .

[0032] In this embodiment, an exhaust port may be further provided on the second solenoid valve 11 , which may be used to exhaust the gas in the ice-melting purge gas path 2 .

[0033] Specifically, a cold trap pool can be set at the position of the cooling coil 12, and a refrigerant is set in the cold trap pool. The refrigerant serves as an intermediate conduction medium to conduct temperature to the cooling coil immersed therein. After the temperature of the cooling coil is assimilated to -78°C, the water vapor in the gas to be dehydrated condenses and the gas becomes a dry gas. A compressor can also be set at the position of the cold trap pool. The compressor is used for refrigeration to take away the heat in the refrigerant to create a low-temperature environment.

[0034] The compressor can be connected to a temperature controller, which monitors the refrigerant temperature in real time and sends the monitored value to the compressor in real time. The compressor adjusts the refrigerant temperature based on the comparison result between the monitored value and the preset value, thereby keeping the refrigerant temperature stable. For example, the refrigerant temperature can be maintained at -70°C.

[0035] The cold trap pool can be tightly wrapped with insulation cotton to further reduce heat exchange and maintain a constant temperature.

[0036] More specifically, the cooling coil 12 can be connected to a robotic arm, which is connected to a controller. The controller controls the cooling coil 12 to be located below or above the coolant liquid level through the robotic arm according to the current operating state. For example, During refrigeration and water removal, the control robot arm drives the cooling coil 12 to sink below the refrigerant liquid surface, so that heat exchange is carried out when the gas passes through the cooling coil 12, so that the gas temperature in the cooling coil 12 is rapidly reduced from the outdoor ambient temperature, and the moisture in the gas is instantly condensed from the gaseous state to solid frost. The formed frost is temporarily stored in the cooling coil 12, and the dry gas is discharged through the cooling coil 12.

[0037] As the frost formed during the cooling and dehydration stage continues to accumulate and increase in the cooling coil 12, the frost may block the cooling coil 12, and eventually ice blockage may occur. Therefore, the cooling coil 12 needs to be regularly de-iced.

[0038] During ice melting and purging, the control robot arm drives the cooling coil 12 away from the refrigerant liquid surface. The temperature of the purge gas after passing through the heating tube 22 can reach 100°C. The frost formed by condensation in the cooling coil 12 during the refrigeration and water removal stage is sublimated into water vapor under the high-temperature and high-flow rate purge gas and is discharged to the external environment through the exhaust port on the second solenoid valve 11 along with the purge gas.

[0039] In the implementation of this application, each ice melting and purge air path 2 includes a purge pump 21, a heating pipe 22 and a third solenoid valve 23; The purge pump 21 can be set at a high position relative to the cooling coil 12 to form a top-down purge. The inlet of the purge pump 21 is used to inhale ambient air, and the outlet of the purge pump 21 is connected to the inlet of the heating pipe 22. The heating pipe 22 has more than two outlets. Each outlet of the heating pipe 22 is connected to the cooling coil 12 of the refrigeration and dehumidification gas circuit 1 through a third solenoid valve 23.

[0040] It can be seen that since the purge pump 21 is arranged at a higher position relative to the cooling coil 12, a top-down purge is formed, thereby fully utilizing the advantages of the combination of kinetic energy and gravitational potential energy to further improve the water removal effect.

[0041] The heating tube 22 may be tightly wrapped with thermal insulation cotton to reduce heat loss from the heating tube 22 .

[0042] The heating tube 22 may be connected to a temperature controller, which monitors the temperature of the heated air and adjusts the heating temperature of the heating tube 22 based on a comparison result between the monitored temperature and a preset temperature.

[0043] During ice melting and purging, indoor ambient air is used as purging gas. The purging gas is sucked into the heating pipe 22 by the purging pump 21. The temperature of the purging gas after passing through the heating pipe 22 can reach 100°C. The frost formed by condensation during the refrigeration and water removal stage in the cooling coil 12 is sublimated into water vapor under the high-temperature and high-flow rate purging gas and discharged into the indoor environment along with the purging gas.

[0044] In an embodiment of the present application, each dry gas collection line 3 includes a fourth solenoid valve 31, the inlet of the fourth solenoid valve 31 is connected to the dry gas outlet of the cooling coil 12 through the third solenoid valve 23, and the outlets of all fourth solenoid valves 31 are connected to the inlet of the analyzer 4 through pipelines.

[0045] In the embodiment of the present application, the controller can switch the gas circuit by controlling the power supply or power off of each valve to realize functions such as water removal switching and purge switching.

[0046] For example, Figure 1 As shown, when two water removal channels, A and B, are provided, the first solenoid valve 5 controls the switching between the water removal channel A and the water removal channel B; The second solenoid valve 11 and the third solenoid valve 23 of the dewatering channel A control the switching between refrigeration dewatering and ice melting and purge of the dewatering channel A; the second solenoid valve 11 and the third solenoid valve 23 of the dewatering channel B control the switching between refrigeration dewatering and ice melting and purge of the dewatering channel B; The fourth solenoid valve 31 of the dry gas collection path 3 connected to the water removal channel A is used to control the discharge of dry gas from the water removal channel A; The fourth solenoid valve 31 of the dry gas collection path 3 connected to the B dehydration channel is used to control the discharge of dry gas from the B dehydration channel.

[0047] In the embodiment of this application, Figure 2 As shown, all water removal channels are set in the chassis. A fan can also be set in the chassis. The fan is used to inhale external air during operation. The heat inside the chassis is blown out through the air outlet by the fan to achieve ventilation of system components and ventilation of the cooling system, so that the temperature inside the chassis is consistent with the outside world, thereby extending the operating life cycle of the equipment.

[0048] Specifically, the chassis includes a back panel and side panels, wherein a window for interacting with the outside world is provided on the back panel, wherein the window includes one or more sample gas inlets (IN), one or more sample gas outlets (OUT1), one or more overflow ports (OUT4), one or more ice melting and purge ports (OUT3), a circular air outlet, a communication interface, a power interface, etc.; The chassis backplane gas interface is connected to the chassis internal bus, and the chassis backplane communication interface is connected to the control system.

[0049] The side panels are provided with louver-shaped air inlets.

[0050] To facilitate a clear understanding of the low-temperature cold trap water removal device provided in the embodiment of the present application, the following describes in detail the method of use of the low-temperature cold trap water removal device with two water removal channels as an example, including the following content: Cold trap cooling: When started for the first time, the controller controls the cooling coils 12 of the two water removal channels to rise away from the refrigerant liquid surface. The ice melting and purge air paths 2 of the two water removal channels work simultaneously to fully melt the ice in the cold traps of the two water removal channels and remove any moisture that may exist in the cooling coils 12. At the same time, the compressor works to create a low-temperature environment. Refrigeration and dehydration and ice melting and purging: After reaching the set refrigeration temperature, the cooling coils 12 of the two dehydration channels are simultaneously immersed below the refrigerant liquid level. The controller issues a command, and the sample gas is sucked into the dehydration channel A through the air pump for refrigeration and dehydration. After refrigeration and dehydration, the sample gas flows out of the cold trap and enters the analyzer 4; After the refrigeration and dehydration gas path 1 of the dehydration channel A has been running for a period of time, the controller issues a command, the first solenoid valve 5 is actuated, and the sample gas refrigeration and dehydration is switched to the dehydration channel B. The dehydration channel B enters the refrigeration and dehydration stage. At the same time, the cooling coil 12 of the dehydration channel A leaves the refrigerant liquid level, and the dehydration channel A enters the ice melting and purge stage. After the B dehydration channel has been running for a period of time, the controller sends a command, the first solenoid valve 5 is activated, and the sample gas refrigeration and dehydration is switched to the A dehydration channel. The A dehydration channel enters the refrigeration and dehydration stage. At the same time, the cooling coil 12 of the B dehydration channel leaves the refrigerant liquid surface, and the B dehydration channel enters the ice melting and purge stage... This cycle repeats continuously to achieve uninterrupted refrigeration and dehydration of the sample gas.

[0051] Obviously, the above-mentioned low-temperature cold trap water removal device provided in the embodiment of the present application can pre-treat the sample gas, realize the double-cut double circulation of the cold trap according to the system design, solve the phenomenon of water vapor fluctuation due to excessive dead volume when the cold trap is switched; solve the problem of incomplete ice melting and blowing in the cold trap channel; thereby achieving effective water removal of the sample gas and extending the operating life cycle of the equipment.

[0052] Although the present application has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications or improvements may be made based on the present application. Therefore, such modifications or improvements, which do not depart from the spirit of the present application, are within the scope of protection claimed in the present application.

Claims

1. A low-temperature cold trap water removal device, comprising: Two or more water removal channels, each of the water removal channels being connected in parallel; Each of the dehydration channels includes a refrigeration dehydration gas circuit and an ice melting and purge gas circuit connected in series; each of the refrigeration dehydration gas circuits is also connected to the inlet of the dry gas collection gas circuit, and the outlet of the dry gas collection gas circuit is used to connect to the analyzer; Each of the dewatering channels is connected to a controller, and the controller is used to control the staggered operation of the refrigeration dewatering air path and the ice melting and purge air path of different dewatering channels.

2. The low-temperature cold trap water removal device according to claim 1, characterized in that: Each of the water removal channels receives the gas to be dehydrated through a first solenoid valve. Each first solenoid valve has an inlet and at least two outlets. The first solenoid valve is connected to the controller and adjusts the opening and closing of the outlet according to the control instruction of the controller.

3. The low-temperature cold trap water removal device according to claim 2, characterized in that: The first solenoid valve is connected to the gas containing bottle to be dehydrated through a valve and an air pump in sequence.

4. The low-temperature cold trap water removal device according to claim 2, characterized in that: Each of the refrigeration and dehumidification gas circuits includes a second solenoid valve and a cooling coil, wherein the inlet of the second solenoid valve is connected to the outlet of the first solenoid valve, and the outlet of the second solenoid valve is connected to the cooling coil. The cooling coil condenses moisture in the gas to be dehydrated into solid frost to obtain dry gas.

5. The low-temperature cold trap water removal device according to claim 4, characterized in that: A cold trap pool is provided at the position of the cooling coil, and a refrigerant is provided in the cold trap pool. The refrigerant serves as an intermediate conduction medium to conduct temperature to the cooling coil immersed therein. After the temperature of the cooling coil is assimilated to -78°C, the water vapor in the gas to be dehydrated condenses and the gas becomes a dry gas. A compressor is also provided at the position of the cold trap pool, and the compressor is used for refrigeration to remove the heat in the refrigerant.

6. The low-temperature cold trap water removal device according to claim 4, characterized in that: The cooling coil is connected to a robotic arm, and the robotic arm is connected to the controller. The controller controls the cooling coil to be located below or above the refrigerant liquid level through the robotic arm according to the current operating state.

7. The low-temperature cold trap dewatering device according to claim 4, characterized in that: Each of the ice-melting purge air paths includes a purge pump, a heating pipe, and a third solenoid valve; The purge pump is arranged at a high position relative to the cooling coil to form a top-down purge. The purge pump inlet is used to inhale ambient air, and the purge pump outlet is connected to the heating pipe inlet. The heating pipe has more than two outlets, and each heating pipe outlet is connected to a cooling coil of the refrigeration and dehumidification gas circuit through a third solenoid valve.

8. The low-temperature cold trap water removal device according to claim 7, characterized in that: Each of the dry gas collection gas lines includes a fourth solenoid valve, the inlet of the fourth solenoid valve is connected to the dry gas outlet of the cooling coil through the third solenoid valve, and the outlets of all the fourth solenoid valves are connected to the inlet of the analyzer through pipelines.

9. The low-temperature cold trap water removal device according to claim 1, characterized in that: All the water removal channels are arranged in the chassis, and a fan is also arranged in the chassis.

10. The low-temperature cold trap water removal device according to claim 9, characterized in that: The chassis includes a back panel and side panels. The back panel is provided with a window for interacting with the outside world, and the side panels are provided with louver-shaped air inlets.

Images