A Condensation Pre-Concentration Equipment for Trace Organic Gases and Its Treatment Method

Abstract

The present invention provides a condensation preconcentration device for trace organic gases and a treatment method thereof, including a water vapor removal device for removing impurity gases mainly composed of water in the sample gas; a carbon dioxide removal device for removing carbon dioxide in the sample gas; a trap device including a first trap and a second trap, the second trap is connected to the carbon dioxide removal device and is used for trapping the sample gas after removing carbon dioxide; a temperature control device for controlling the temperatures of the water vapor removal device and the trap device; a valve group device including a plurality of valves, all of which are multi-channel switching valves and are at least used for introducing the sample gas and the drying gas; a carrier gas input device including a first carrier gas, a second carrier gas and a third carrier gas, wherein the first carrier gas is used to drive the transfer of the sample, the second carrier gas is used to drive the sample gas into the analytical instrument for detection, and the third carrier gas is used to backflush the carbon dioxide in the carbon dioxide removal device; and an analysis device for analyzing the sample gas.

Description

Technical Field

[0001] The present invention relates to the field of volatile gas analysis, and particularly to a condensation preconcentration device for trace organic gases and a treatment method thereof. Background Art

[0002] Trace organic gases refer to organic gas substances with extremely low content (ppt level) in the air. They have a long atmospheric lifetime, a wide variety of types, and a strong greenhouse effect. Some substances (containing halogen atoms such as chlorine and bromine) can even destroy stratospheric ozone, posing a hazard to human health, and are a class of substances that are globally focused on. Trace organic gases are extremely volatile, and the boiling points of some species are below -120 degrees Celsius. Generally, a method combining low temperature and adsorbents is used to trap them. Ordinary condensation preconcentration devices are difficult to efficiently trap the above-mentioned species with extremely high volatility and extremely low concentration, and do not remove interfering species, resulting in problems such as inability to measure or low measurement accuracy; some complex condensation preconcentration devices perform relatively simple water and carbon dioxide removal, and can achieve the enrichment of the above substances, but the injection volume is insufficient and the water removal depth is not enough, leading to bottlenecks in the sensitivity and detection limit of the instrument. With the emergence of minor CFC and minor HCFC in the atmosphere in recent years attracting attention, the concentrations of these species are as low as a few to hundreds of ppq (10 -15 ), so there is an urgent need for trace organic gas analyzers with higher sensitivity and higher detection limits, and it is particularly necessary to develop corresponding condensation preconcentration devices and treatment methods. Summary of the Invention

[0003] The present invention is made to solve the above problems, and aims to provide a condensation preconcentration device for trace organic gases and a treatment method thereof.

[0004] The present invention provides a condensation preconcentration device for trace organic gases, having the following characteristics, including: a water vapor removal device for removing impurity gases mainly composed of water in the sample gas; a carbon dioxide removal device for removing carbon dioxide in the sample gas; a trap device including a first trap and a second trap, the second trap being connected to the carbon dioxide removal device for trapping the sample gas after carbon dioxide removal; a temperature control device for controlling the temperatures of the water vapor removal device and the trap device; a valve group device including several valves, all of which are multi-channel switching valves, at least for introducing the sample gas and the dry gas; a carrier gas input device including a first carrier gas, a second carrier gas, and a third carrier gas, wherein the first carrier gas is used to drive the transfer of the sample gas, the second carrier gas is used to drive the sample gas into the analytical instrument for detection, and the third carrier gas is used to backflush the carbon dioxide in the carbon dioxide removal device; and an analysis device for analyzing the sample gas.

[0005] In the trace organic gas condensation preconcentration equipment provided by the present invention, it may also have the following characteristics: Among them, the water vapor removal device is connected to the dry gas inlet and includes an impurity removal trap, a first dryer, and a second dryer. The second dryer is connected to the first trapping trap. The impurity removal trap is used to deeply remove impurity gases mainly composed of water at extremely low temperatures, and the extremely low temperature is -50 to -70 °C.

[0006] In the trace organic gas condensation preconcentration equipment provided by the present invention, it may also have the following characteristics: Among them, the dry gas inlet is controlled by a solenoid valve and includes two paths. One path is used to lead to the first dryer and the second dryer for preliminary water removal, and the other path is used to be connected to the valve group device to blow out the impurity gas in the impurity removal trap.

[0007] In the trace organic gas condensation preconcentration equipment provided by the present invention, it may also have the following characteristics: Among them, the temperature control device includes a refrigeration device, a cold plate, a first heating control device, a second heating control device, and a third heating control device. The cold end of the refrigeration device is connected to the cold plate, and the cold plate is connected to the impurity removal trap, the first trapping trap, and the second trapping trap. The first heating control device and the second heating control device are respectively connected to the first trapping trap and the second trapping trap through wires, and the third heating control device is connected to the impurity removal trap.

[0008] In the trace organic gas condensation preconcentration equipment provided by the present invention, it may also have the following characteristics: Among them, thermocouple temperature measurement points are arranged between the first heating control device and the first trapping trap, between the second heating control device and the second trapping trap, and between the third heating control device and the impurity removal trap. The thermocouple temperature measurement points are in contact with the pipeline through heat-conducting paste for temperature measurement, so as to improve the consistency and accuracy of the temperature measurement of the first trapping trap, the second trapping trap, and the impurity removal trap.

[0009] In the trace organic gas condensation preconcentration equipment provided by the present invention, it may also have the following characteristics: It further includes a vacuum chamber, which seals the outer walls of the impurity removal trap, the first trapping trap, the second trapping trap, the cold plate, and the refrigeration device and uses a vacuum pump to evacuate the air to isolate the air and prevent a large amount of water vapor from freezing on the outer walls of the cold plate and the refrigeration device due to low temperature, thereby affecting the temperature control of the first trapping trap, the second trapping trap, and the impurity removal trap.

[0010] In the condensation preconcentration equipment for trace organic gases provided by the present invention, it may further have the following characteristics: Among them, the valve group device includes a first valve, a second valve, a third valve, a fourth valve, a fifth valve, and a sixth valve. The first valve is a multi-position selection valve. One of its valve positions is connected to a drying gas cylinder for inputting drying gas to blow and remove the impurity gas trapped by the impurity trap. The other three valve positions are connected to a standard gas cylinder for respectively inputting ordinary standard gas, spare standard gas, and quality control standard gas to analyze and calculate the concentrations of various species in the sample and for quality control. The other valve positions are connected to a sample gas cylinder for inputting sample gas. The second valve is a multi-way two-position valve connected to a first dryer, a third valve, and a fourth valve. The third valve is an irregular valve controlled by an electromagnetic valve and connected to a first trap, an impurity trap, and a second drying gas inlet, including two paths. One of the paths is for leading to the first device and is connected to the second valve. The fourth valve is a multi-way two-position valve connected to the second valve, the sixth valve, and a first path of carrier gas. The fifth valve is an irregular valve connected to a second trap, the sixth valve, and a third path of carrier gas. The sixth valve is a multi-way two-position valve connected to a carbon dioxide removal device, the fourth valve, the fifth valve, and a second path of carrier gas.

[0011] In the condensation preconcentration equipment for trace organic gases provided by the present invention, it may further have the following characteristics: Among them, the carbon dioxide removal device is MS4A molecular sieve, and the carbon dioxide removal method of the carbon dioxide removal device includes a chemical method and a molecular sieve filtration method.

[0012] The present invention also provides a treatment method for a condensation preconcentration device of trace organic gases, which specifically includes the following steps: S1, the temperature control device includes a refrigeration device, a cold plate, a first heating control device, a second heating control device, and a third heating control device. The water vapor removal device includes an impurity removal trap, a first dryer, and a second dryer. The valve group device includes a first valve, a second valve, a third valve, a fourth valve, a fifth valve, and a sixth valve. The cold end of the refrigeration device transfers cold energy to the cold plate, and the cold plate then transfers the cold energy to the impurity removal trap, the first trapping trap, and the second trapping trap, so that the temperatures of the impurity removal trap, the first trapping trap, and the second trapping trap are reduced, and the lowest temperature is -190 °C; S2, the sample gas enters the pipeline through the first valve, sequentially passes through the impurity removal trap, the first dryer, and the second dryer for deep water removal, and then is introduced into the first trapping trap for enrichment; S3, through the first heating control device, the temperature of the first trapping trap is raised until the temperature is higher than the transfer temperature of the boiling point of the low-boiling species in the sample gas. The low-boiling species and the first carrier gas enter the carbon dioxide removal device, and carbon dioxide is captured by the carbon dioxide removal device. Then, the low-boiling species and the first carrier gas are transferred to the second trapping trap for enrichment; S4, through the second heating control device, the temperature of the second trapping trap is raised until the temperature is slightly lower than the boiling point of the low-boiling species, so as to purge argon, krypton, xenon, methane, nitrogen, and oxygen in the sample gas out of the pipeline. At the same time, the second carrier gas back blows the carbon dioxide captured in the carbon dioxide removal device; S5, through the second heating control device, the temperature of the second trapping trap is raised until the low-boiling species are thermally desorbed, and then the low-boiling species are introduced into the analytical instrument for detection under the drive of the third carrier gas, so as to realize the analysis of the low-boiling species; S6, through the first heating control device, the temperature of the first trapping trap is raised until the temperature is slightly lower than the boiling point of the high-boiling species in the sample gas, so that the impurity gas with a boiling point between the high and low-boiling species in the first trapping trap is purged out of the pipeline; S7, connect the carbon dioxide removal device to the second carrier gas and back blow the adsorbed carbon dioxide during the purging process; S8, through the first heating control device, the temperature of the first trapping trap is raised until the high-boiling species are thermally desorbed and transferred to the second trapping trap for enrichment along with the first carrier gas. At the same time, the second carrier gas back blows the carbon dioxide captured in the carbon dioxide removal device; S9, through the second heating control device, the temperature of the second trapping trap is raised until the temperature is slightly lower than the boiling point of the high-boiling species for impurity removal; S10, further raise the temperature of the second trapping trap until the high-boiling species are thermally desorbed, and then the high-boiling species are introduced into the analytical instrument for detection under the drive of the third carrier gas, so as to realize the analysis of the high-boiling species; S11, through the third heating control device, raise the temperature of the impurity removal trap until the impurity gas in the impurity removal trap is thermally desorbed and discharged along with the drying gas.

[0013] Functions and effects of the invention

[0014] A condensation preconcentration device and a treatment method for trace organic gases according to the present invention perform low-temperature preconcentration on trace organic gases and independent impurity removal trap for deep water removal, removal of impurities such as carbon dioxide, and thermal desorption treatment, realizing the enrichment and separation of no less than 55 species and minimizing the interference of impurities, thereby improving the detection accuracy of the above substances. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic structural diagram of a trace organic gas condensation preconcentration device provided by an embodiment of the present invention.

[0016] Figure 2 It is a schematic diagram of the water removal and enrichment stage of a trace organic gas condensation preconcentration device provided by an embodiment of the present invention.

[0017] Figure 3 It is a schematic diagram of the transfer and secondary enrichment of low-boiling species in a trace organic gas condensation preconcentration device provided by an embodiment of the present invention.

[0018] Figure 4 It is a schematic diagram of purging impurities and back-blowing carbon dioxide after the secondary enrichment of low-boiling species in a trace organic gas condensation preconcentration device provided by an embodiment of the present invention.

[0019] Figure 5 It is a schematic diagram of transferring low-boiling species to an analytical instrument and purging impurities before the secondary enrichment of high-boiling species in a trace organic gas condensation preconcentration device provided by an embodiment of the present invention.

[0020] Figure 6 It is a schematic diagram of back-blowing carbon dioxide after purging impurities before the secondary enrichment of high-boiling species in a trace organic gas condensation preconcentration device provided by an embodiment of the present invention.

[0021] Figure 7 It is a schematic diagram of the transfer and secondary enrichment of high-boiling species in a trace organic gas condensation preconcentration device provided by an embodiment of the present invention.

[0022] Figure 8 It is a schematic diagram of purging impurities after the secondary enrichment of high-boiling species in a trace organic gas condensation preconcentration device provided by an embodiment of the present invention.

[0023] Figure 9 It is a schematic diagram of transferring high-boiling species to an analytical instrument in a trace organic gas condensation preconcentration device provided by an embodiment of the present invention.

[0024] Figure 10 It is a schematic diagram of purging and draining water from the impurity removal trap after all the species to be detected in a trace organic gas condensation preconcentration device provided by an embodiment of the present invention leave the gas path and start analysis. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] In the description of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "linkage" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a connection that allows mutual communication; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0026] In order to make the technical means, creative features, achieved purposes, and effects of the present invention easy to understand, the following embodiments will specifically describe the trace organic gas condensation preconcentration equipment of the present invention in conjunction with the accompanying drawings.

[0027] Figure 1 It is a schematic structural diagram of the trace organic gas condensation preconcentration equipment provided by the embodiment of the present invention.

[0028] As Figure 1 shown, the condensation preconcentration equipment 100 for trace organic gases in this embodiment includes: a water vapor removal device 90, a carbon dioxide removal device 20, a trap device 30, a temperature control device 40, a valve group device 50, a carrier gas input device 60, an analysis device 70, and a vacuum chamber 80.

[0029] The water vapor removal device 90 is used to remove impurity gases mainly composed of water in the sample gas.

[0030] The water vapor removal device 90 is connected to the dry gas inlet and includes an impurity removal trap, a first dryer, and a second dryer.

[0031] Both the first dryer and the second dryer are Nafion water removal tubes. The Nafion water removal tubes are used to remove most of the water vapor in the sample, preventing too much water from being trapped by the impurity removal trap and the trap, occupying more adsorption sites, thereby reducing the water removal ability of the impurity removal trap and affecting its trapping of the target substance. Its water removal principle is to perform water vapor exchange between the sample gas and the dry gas, and the dry gas flows in the opposite direction to the sample gas flow path.

[0032] The impurity removal trap is used to remove a small part of the water vapor in the sample gas that has not been removed by the Nafion water removal tube. Its principle is to use cryogenic condensation to deeply remove water, such as -60°C, at which time the saturated vapor pressure of ice is less than 1 Pa.

[0033] Among them, the first dryer is connected to the sample gas inlet. The second dryer is connected to the first trap. The impurity removal trap is used to deeply remove impurity gases mainly composed of water at extremely low temperatures. The extremely low temperature is -50 to -70°C. Removing the interference of water vapor in the sample helps to improve the analysis sensitivity and accuracy of subsequent analytical instruments.

[0034] The dry gas inlet is controlled by a solenoid valve and includes two paths. One path is used to lead to the first dryer and the second dryer for preliminary water removal, and the other path is used to connect to the valve group device to blow and remove the impurity gas in the impurity trap.

[0035] The carbon dioxide removal device 20 is used to remove carbon dioxide from the sample gas.

[0036] In this embodiment, the carbon dioxide removal device 20 is an MS4A molecular sieve, and the carbon dioxide removal method of the carbon dioxide removal device includes a chemical method and a molecular sieve filtration method.

[0037] The MS4A molecular sieve is used to remove carbon dioxide from the primary sample gas that has already had water vapor removed. Its removal principle is based on the different particle sizes of different gas molecules, allowing the target substance to pass through without loss while leaving most of the carbon dioxide inside the molecular sieve. The secondary sample gas from which water and carbon dioxide have been removed will be enriched in the second trap in a low-temperature state.

[0038] The second trap is connected to the carbon dioxide removal device 20 and is used to trap the sample gas after carbon dioxide has been removed.

[0039] The temperature control device 40 is used to control the temperatures of the water vapor removal device 90 and the trap device 30.

[0040] The temperature control device 40 includes a refrigeration device, a cold plate, a first heating control device, a second heating control device, and a third heating control device. The cold end of the refrigeration device is connected to the cold plate, the cold plate is connected to the impurity trap, the first trap, and the second trap. The first heating control device and the second heating control device are respectively connected to the first trap and the second trap through wires, and the third heating control device is connected to the impurity trap.

[0041] Thermocouple temperature measurement points are provided between the first heating control device and the first trap, between the second heating control device and the second trap, and between the third heating control device and the impurity trap. The thermocouple temperature measurement points are in contact with the pipeline through thermal paste for temperature measurement, thereby improving the consistency and accuracy of the temperature measurement of the first trap, the second trap, and the impurity trap.

[0042] The vacuum chamber 80 seals the outer walls of the impurity trap, the first trap, the second trap, the cold plate, and the refrigeration device and uses a vacuum pump to evacuate the air to isolate the air and prevent a large amount of water vapor from freezing on the outer walls of the cold plate and the refrigeration device due to low temperature, thereby affecting the temperature control of the first trap, the second trap, and the impurity trap.

[0043] The temperature control principle is as follows: The cold plate is connected to the cold end of the refrigeration device, thereby transferring cold energy to the impurity trap, the first trap, and the second trap to quickly cool them, and the target species are trapped. The heating control device can heat the trap by applying a current, enabling the thermal desorption of the target substance. In addition, the use of the vacuum chamber 80 can prevent a large amount of water vapor from condensing on the outer walls of the impurity trap, the first trap, the second trap, the cold plate, and the cold end of the refrigeration device, thereby affecting the accuracy and stability of the trap temperature control.

[0044] The carrier gas input device 60 includes a first carrier gas, a second carrier gas, and a third carrier gas. The first carrier gas is used to drive the transfer of the sample gas, the second carrier gas is used to backflush the carbon dioxide in the carbon dioxide removal device 20, and the third carrier gas is used to drive the sample gas into the analytical instrument for detection.

[0045] The analysis device 70 is used to analyze the sample gas.

[0046] The valve group device 50 includes several valves. In this embodiment, it specifically includes a first valve V1, a second valve V2, a third valve V3, a fourth valve V4, a fifth valve V5, and a sixth valve V6, all of which are multi-channel switching valves, at least used for introducing the sample gas and the drying gas. Each component in the pipeline is connected to each other through the valve group device 50. By precisely switching each valve to different valve positions, the connection sequence of the pipeline can be arbitrarily switched to meet different connection requirements, ensuring the repeatability of the experiment.

[0047] The first valve V1 is a multi-position selection valve and includes ten interfaces.

[0048] Interfaces 1, 3, 5, 7, and 9 are connected to the sample gas cylinder for inputting the sample gas. Among them, interface 11 is connected to the drying gas cylinder for inputting the drying gas to blow out the impurity gas trapped by the impurity trap. Interface 17 is connected to the air for inputting the air. Interfaces 13, 15, and 19 are connected to the standard gas cylinder for inputting the ordinary standard gas, the spare standard gas, and the quality control standard gas respectively, so as to analyze and calculate the concentrations of each species in the sample and perform quality control.

[0049] The second valve V2 is a multi-way two-position valve and includes six interfaces.

[0050] Among them, interface 1 is sequentially connected to the MFC inlet pressure sensor, the filter, the MFC, and the vacuum pump, and interface 2 is sequentially connected to the first dryer, the injection pressure sensor, the pressure stabilizing valve, and the sample gas inlet. The MFC is a flow controller used to control the inlet flow of the sample gas.

[0051] The third valve V3 is an irregular valve and includes six interfaces.

[0052] Among them, interface 1 is successively connected to the impurity trap and interface 4, and interface 2 is successively connected to the second dryer, the first trap, and interface 5 for enriching the sample gas after deep water removal. Interface 3 is connected to interface 3 of the second valve V2, and interface 6 is connected to interface 6 of the second valve V2.

[0053] The fourth valve V4 is a multi-way two-position valve and includes four interfaces.

[0054] Among them, interface 3 is connected to the first carrier gas line to drive the transfer of the sample, and interface 4 is connected to interface 5 of the second valve V2.

[0055] The fourth valve V4 is used to change the gas flow direction of the carrier gas in the first trap during the second species transfer (high-boiling species), which helps to improve the analysis accuracy of the species to be measured in the second transfer.

[0056] The fifth valve V5 is an irregular valve and includes six interfaces.

[0057] Among them, interface 1 is successively connected to the differential pressure sensor and the trap flowmeter, interface 2 is successively connected to the second trap and interface 5, and interface 3 is connected to the third carrier gas line to drive the sample gas into the analytical instrument for detection.

[0058] The sixth valve V6 is a multi-way two-position valve and includes ten interfaces.

[0059] Among them, interface 1 is connected to interface 4 of the fifth valve V5, interface 2 is successively connected to the analysis device 70, interface 3 is connected to the analysis device 70 and interface 10, interface 4 is connected to the second carrier gas line to backflush the carbon dioxide in the carbon dioxide removal device 20, interface 5 is connected to the column backflush flowmeter, interface 6 is successively connected to the carbon dioxide removal device 20 and interface 9, interface 7 is connected to interface 1 of the fourth valve V4, and interface 8 is connected to interface 6 of the fifth valve V5.

[0060] The sixth valve V6 is used to control the gas flow direction (carbon dioxide removal or backflush) of the carrier gas in the carbon dioxide removal device 20, and at the same time control the connection state between the sample gas and the subsequent analytical instrument.

[0061] In this embodiment, the second valve V2 has two valve positions during operation:

[0062] Valve position A: Interface 2 is connected to interface 3, interface 4 is connected to interface 5, and interface 6 is connected to interface 1.

[0063] Valve position B: Interface 1 is connected to interface 2, interface 3 is connected to interface 4, and interface 5 is connected to interface 6.

[0064] The third valve V3 has three valve positions during operation:

[0065] Valve position 1: Interface 1 is connected to interface 6, and interface 3 is connected to interface 4.

[0066] Valve position 3: Interface 2 is connected to interface 3, and interface 5 is connected to interface 6.

[0067] Valve position 12: Interface 1 is connected to interface 2, interface 3 is connected to interface 4, and interface 5 is connected to interface 6.

[0068] The fourth valve V4 has two valve positions during operation:

[0069] Valve position A: Interface 1 is connected to interface 2, and interface 3 is connected to interface 4.

[0070] Valve position B: Interface 2 is connected to interface 3, and interface 1 is connected to interface 4.

[0071] The fifth valve V5 has three valve positions during operation:

[0072] Valve position 1: Interface 3 is connected to interface 4, and interface 6 is connected to interface 1.

[0073] Valve position 2: Interface 2 is connected to interface 3, interface 4 is connected to interface 5, and interface 6 is connected to interface 1.

[0074] Valve position 12: Interface 1 is connected to interface 2, interface 3 is connected to interface 4, and interface 5 is connected to interface 6.

[0075] The sixth valve V6 has two valve positions during operation:

[0076] Valve position A: Interface 2 is connected to interface 3, interface 4 is connected to interface 5, interface 6 is connected to interface 7, interface 8 is connected to interface 9, and interface 10 is connected to interface 1.

[0077] Valve position B: Interface 1 is connected to interface 2, interface 3 is connected to interface 4, interface 5 is connected to interface 6, interface 7 is connected to interface 8, and interface 9 is connected to interface 10.

[0078] In this embodiment, the connection sequence of each device in the water removal and enrichment stage is: the sample gas outlet is connected to the first dryer, then connected to the impurity removal trap, then connected to the second dryer, then connected to the first trap, and finally connected to the MFC.

[0079] In the analysis stage: The first trap is connected to the carbon dioxide removal device 20, then connected to the second trap, and finally connected to the analysis device 70.

[0080] Figure 2 It is a schematic diagram of the water removal and enrichment stage of the trace organic gas condensation pre-concentration equipment provided by the embodiment of the present invention. Figure 3Schematic diagram of low-boiling species transfer and secondary enrichment in the trace organic gas condensation preconcentration equipment provided by the embodiment of the present invention. Figure 4 Schematic diagram of purging impurities and back-blowing carbon dioxide after secondary enrichment of low-boiling species in the trace organic gas condensation preconcentration equipment provided by the embodiment of the present invention. Figure 5 Schematic diagram of transferring low-boiling species to the analytical instrument and purging impurities before secondary enrichment of high-boiling species in the trace organic gas condensation preconcentration equipment provided by the embodiment of the present invention. Figure 6 Schematic diagram of back-blowing carbon dioxide after purging impurities before secondary enrichment of high-boiling species in the trace organic gas condensation preconcentration equipment provided by the embodiment of the present invention. Figure 7 Schematic diagram of high-boiling species transfer and secondary enrichment in the trace organic gas condensation preconcentration equipment provided by the embodiment of the present invention. Figure 8 Schematic diagram of purging impurities after secondary enrichment of high-boiling species in the trace organic gas condensation preconcentration equipment provided by the embodiment of the present invention. Figure 9 Schematic diagram of transferring high-boiling species to the analytical instrument in the trace organic gas condensation preconcentration equipment provided by the embodiment of the present invention. Figure 10 Schematic diagram of purging and draining the impurity trap after all the species to be measured in the trace organic gas condensation preconcentration equipment provided by the embodiment of the present invention leave the gas path and start analysis.

[0081] In this embodiment, the treatment method of the trace organic gas condensation preconcentration equipment 100 specifically includes the following steps:

[0082] S1, as Figure 2 shown, the second valve V2 adopts its valve position A, the third valve V3 adopts its valve position 12, the fourth valve V4 adopts its valve position B, the fifth valve V5 adopts its valve position 1, and the sixth valve V6 adopts its valve position B. The cold end of the refrigeration equipment transfers the cold quantity to the cold plate, and the cold plate then transfers the cold quantity to the impurity trap, the first trap, and the second trap, so that the temperatures of the impurity trap, the first trap, and the second trap are reduced to -165 °C.

[0083] S2, according to Figure 2 the gas path indicated by the arrow in

[0084] S3, as Figure 3 shown, according to Figure 3For the gas path indicated by the arrow, the second valve V2 adopts its valve position B, the third valve V3 adopts its valve position 3, the fourth valve V4 adopts its valve position B, the fifth valve V5 adopts its valve position 12, and the sixth valve V6 adopts its valve position A. Through the first heating control device, the temperature of the first trap is raised until the temperature is higher than the transfer temperature of the boiling point of the low-boiling species in the sample gas. The low-boiling species and the first carrier gas enter the carbon dioxide removal device 20, and carbon dioxide is captured by the carbon dioxide removal device 20. Subsequently, the low-boiling species and the first carrier gas are transferred to the second trap for enrichment.

[0085] S4, as Figure 4 shown, according to Figure 4 For the gas path indicated by the arrow, the second valve V2 adopts its valve position A, the third valve V3 adopts its valve position 1, the fourth valve V4 adopts its valve position B, the fifth valve V5 adopts its valve position 12, and the sixth valve V6 adopts its valve position B. Through the second heating control device, the temperature of the second trap is raised until the temperature is slightly lower than the boiling point of the low-boiling species, so as to purge argon, krypton, xenon, methane, nitrogen, and oxygen in the sample gas out of the pipeline (the gas path indicated by the first arrow). At the same time, the second carrier gas backflushes the carbon dioxide captured in the carbon dioxide removal device 20 (the gas path indicated by the second arrow).

[0086] S5, as Figure 5 shown (the gas path indicated by the third arrow), the second valve V2 adopts its valve position B, the third valve V3 adopts its valve position 3, the fourth valve V4 adopts its valve position B, the fifth valve V5 adopts its valve position 2, and the sixth valve V6 adopts its valve position A. Through the second heating control device, the temperature of the second trap is raised until the low-boiling species is thermally desorbed, and then the low-boiling species is introduced into the analytical instrument for detection under the drive of the third carrier gas, thereby realizing the analysis of the low-boiling species.

[0087] Generally, the purge temperature of the low-boiling species needs to be determined according to the boiling points and polarities of the target gas and the impurity gas. The purge temperature in this embodiment is -122 °C.

[0088] S6, as Figure 5 shown (the gas path indicated by the fourth arrow), the second valve V2 adopts its valve position B, the third valve V3 adopts its valve position 3, the fourth valve V4 adopts its valve position B, the fifth valve V5 adopts its valve position 2, and the sixth valve V6 adopts its valve position A. Through the first heating control device, the temperature of the first trap is raised until the temperature is slightly lower than the boiling point of the high-boiling species in the sample gas, so as to purge the impurity gas with a boiling point between the high- and low-boiling species in the first trap out of the pipeline.

[0089] S7, as Figure 6 shown, according to Figure 6The gas path indicated by the arrow. The second valve V2 adopts its valve position B, the third valve V3 adopts its valve position 3, the fourth valve V4 adopts its valve position B, the fifth valve V5 adopts its valve position 1, and the sixth valve V6 adopts its valve position B. Connect the carbon dioxide removal device 20 to backflush the carbon dioxide adsorbed during the purge process of the second carrier gas.

[0090] S8, as Figure 7 shown, according to Figure 7 the gas path indicated by the arrow. The second valve V2 adopts its valve position B, the third valve V3 adopts its valve position 3, the fourth valve V4 adopts its valve position A, the fifth valve V5 adopts its valve position 12, and the sixth valve V6 adopts its valve position B. Through the first heating control device, raise the temperature of the first trap until the high-boiling species are thermally desorbed and transferred to the second trap for enrichment with the first carrier gas. At the same time, the second carrier gas backflushes the carbon dioxide captured in the carbon dioxide removal device 20.

[0091] S9, as Figure 8 shown, according to Figure 8 the gas path indicated by the arrow. The second valve V2 adopts its valve position A, the third valve V3 adopts its valve position 1, the fourth valve V4 adopts its valve position A, the fifth valve V5 adopts its valve position 12, and the sixth valve V6 adopts its valve position B. Through the second heating control device, raise the temperature of the second trap until the temperature is slightly lower than the boiling point of the high-boiling species for impurity removal.

[0092] S10, as Figure 9 shown, according to Figure 9 the gas path indicated by the arrow. The second valve V2 adopts its valve position A, the third valve V3 adopts its valve position 1, the fourth valve V4 adopts its valve position A, the fifth valve V5 adopts its valve position 2, and the sixth valve V6 adopts its valve position B. Further raise the temperature of the second trap until the high-boiling species are thermally desorbed, and then under the drive of the third carrier gas, introduce the high-boiling species into the analytical instrument for detection, thereby realizing the analysis of the high-boiling species.

[0093] S11, as Figure 10 shown, according to Figure 10 the gas path indicated by the arrow. The second valve V2 adopts its valve position A, the third valve V3 adopts its valve position 1, the fourth valve V4 adopts its valve position A, the fifth valve V5 adopts its valve position 1, and the sixth valve V6 adopts its valve position B. Set the MFC to an appropriate value. Through the third heating control device, raise the temperature of the impurity removal trap until the impurity gas in the impurity removal trap is thermally desorbed and discharged with the drying gas.

[0094] Generally, the purge temperature of the high-boiling species needs to be determined according to the boiling points and polarities of the target gas and the impurity gas. The purge temperature in this embodiment is -68 °C.

[0095] Functions and effects of the embodiment

[0096] A condensation preconcentration device and a treatment method for trace organic gases according to the present invention achieve the enrichment and separation of no less than 55 species and minimize the interference of impurities by performing low-temperature preconcentration on trace organic gases, depth dehydration and removal of impurities such as carbon dioxide in an independent impurity removal trap, and thermal desorption, thereby improving the detection accuracy of the above substances.

[0097] The present invention greatly improves the accuracy and precision of analysis by increasing the sample injection volume, adding a separate impurity removal trap, and measuring the temperature by contacting the thermocouple temperature measurement point with the pipeline through thermal paste.

[0098] Under the condition of -60 °C, the present invention efficiently removes the water vapor brought by large-volume sample injection and hinders the high-precision and high-sensitivity detection through the precise control of a newly added irregular valve, heating control device, and flow control device, and improves the sensitivity and detection limit of the analytical instrument on the premise of meeting the large sample injection volume and maximizing the removal of water and carbon dioxide.

[0099] The present invention optimizes the temperature control system, enhances the heat transfer efficiency between the trapping trap and the impurity removal trap and the refrigeration end, reduces the heat loss at the same time, and improves the speed, accuracy, and stability of temperature control.

[0100] Those skilled in the art of this industry should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A condensation pre-concentration device for trace organic gases, characterized in that: include: A water vapor removal device is used to remove impurity gases, mainly water, from the sample gas; A carbon dioxide removal device, used to remove carbon dioxide from the sample gas; A trap device, comprising a first trap and a second trap, wherein the second trap is connected to the carbon dioxide removal device and is used to capture the sample gas after the carbon dioxide is removed; a temperature control device for controlling the temperature of the water vapor removal device and the capture trap device; The valve group device includes a plurality of valves, all of which are multi-channel switching valves, and are used for at least introducing sample gas and drying gas; A carrier gas input device, comprising a first carrier gas, a second carrier gas and a third carrier gas, wherein the first carrier gas is used to drive the sample gas to transfer, the second carrier gas is used to backflush the carbon dioxide in the carbon dioxide removal device, and the third carrier gas is used to drive the sample gas into the analytical instrument for detection; an analysis device for analyzing the sample gas, The water vapor removal device is connected to the dry gas inlet, and includes a degassing trap, a first dryer and a second dryer. The second dryer is connected to the first trap. The degassing trap is used to remove impurity gases mainly composed of water at an extremely low temperature depth. The extremely low temperature is -50~-70°C. The dry gas inlet is controlled by a solenoid valve and includes two routes, one of which is used to lead to the first dryer and the second dryer to perform preliminary water removal, and the other is used to connect to the valve group device to purge the impurity gas in the impurity removal trap. The temperature control device includes a refrigeration device, a cold plate, a first heating control device, a second heating control device and a third heating control device. The cold end of the refrigeration device is connected to the cold plate, the cold plate is connected to the impurity removal trap, the first capture trap and the second capture trap, the first heating control device and the second heating control device are respectively connected to the first capture trap and the second capture trap through wires, and the third heating control device is connected to the impurity removal trap.

2. The condensation pre-concentration device for trace organic gases according to claim 1, characterized in that: in, Thermocouple temperature measuring points are arranged between the first heating control device and the first trap, between the second heating control device and the second trap, and between the third heating control device and the impurity removal trap. The thermocouple temperature measuring points measure the temperature by contacting the pipeline with thermal conductive paste, thereby improving the consistency and accuracy of the temperature measurement of the first trap, the second trap and the impurity removal trap.

3. The condensation pre-concentration equipment for trace organic gases according to claim 1, characterized in that: Also includes: A vacuum chamber is provided to seal the outer wall of the impurity removal trap, the first capture trap, the second capture trap, the cold plate and the refrigeration equipment and evacuate the outer wall of the refrigeration equipment using a vacuum pump to isolate the air and prevent a large amount of water vapor from freezing on the outer wall of the cold plate and the refrigeration equipment due to low temperature, thereby affecting the temperature control of the first capture trap, the second capture trap and the impurity removal trap.

4. The condensation pre-concentration device for trace organic gases according to claim 1, characterized in that: in, The valve group device includes a first valve, a second valve, a third valve, a fourth valve, a fifth valve and a sixth valve. The first valve is a multi-position selector valve, one of which is connected to a dry gas cylinder for inputting the dry gas to purge the impurity gas captured by the impurity trap, and the other three valve positions are connected to standard gas cylinders for inputting common standard gas, spare standard gas and quality control standard gas, respectively, so as to analyze and calculate the concentration of each species in the sample and quality control, and the other valve positions are connected to sample gas cylinders for inputting the sample gas. The second valve is a multi-way two-position valve connected to the first dryer, the third valve and the fourth valve. The third valve is an irregular valve, connected to the first trap, the impurity removal trap, the second dryer and the second valve. The fourth valve is a multi-way two-position valve, connected to the second valve, the sixth valve and the first carrier gas. The fifth valve is an irregular valve, connected to the second trap, the sixth valve and the third carrier gas. The sixth valve is a multi-way two-position valve, which is connected to the carbon dioxide removal device, the fourth valve, the fifth valve and the second carrier gas.

5. The condensation pre-concentration equipment for trace organic gases according to claim 1, characterized in that: in, The carbon dioxide removal device is a MS4A molecular sieve, and the carbon dioxide removal method of the carbon dioxide removal device includes a chemical method and a molecular sieve filtration method.

6. A method for treating a trace organic gas condensation pre-concentration device according to any one of claims 1 to 5, characterized in that: The specific steps include: S1, the temperature control device includes a refrigeration device, a cold plate, a first heating control device, a second heating control device and a third heating control device, the water vapor removal device includes a de-impurity trap, a first dryer and a second dryer, the valve group device includes a first valve, a second valve, a third valve, a fourth valve, a fifth valve and a sixth valve, the cold end of the refrigeration device transfers cold energy to the cold plate, and the cold plate transfers cold energy to the de-impurity trap, the first trap and the second trap, so that the temperature of the de-impurity trap, the first trap and the second trap is reduced, and the lowest temperature is -190°C; S2, the sample gas enters the pipeline through the first valve, passes through the impurity removal trap, the first dryer and the second dryer for deep water removal, and then enters the first capture trap for enrichment; S3, raising the temperature of the first trap by a first heating control device until the temperature is higher than the boiling point transfer temperature of the low-boiling-point species in the sample gas, the low-boiling-point species and the first carrier gas enter the carbon dioxide removal device, carbon dioxide is captured by the carbon dioxide removal device, and then the low-boiling-point species and the first carrier gas are transferred to the second trap for enrichment; S4, raising the temperature of the second trap by a second heating control device until the temperature is slightly lower than the boiling point of the low-boiling-point species, thereby blowing argon, krypton, xenon, methane, nitrogen and oxygen in the sample gas out of the pipeline, and at the same time, back-flushing the carbon dioxide captured in the carbon dioxide removal device by a second carrier gas; S5, raising the temperature of the second trap by a second heating control device until the low-boiling-point species are thermally desorbed, and then passing the low-boiling-point species into an analytical instrument for detection under the drive of the third carrier gas, thereby realizing the analysis of the low-boiling-point species; S6, raising the temperature of the first trap by a first heating control device until the temperature is slightly lower than the boiling point of the high-boiling-point species in the sample gas, so that the impurity gas with a boiling point between the high-boiling-point species and the low-boiling-point species in the first trap is purged out of the pipeline; S7, connecting the carbon dioxide removal device to the second carrier gas to back-blow the carbon dioxide adsorbed during the purge process; S8, raising the temperature of the first trap by a first heating control device until the high-boiling-point species are thermally desorbed and transferred to the second trap with the first carrier gas for enrichment, and at the same time, the second carrier gas back-flushes the carbon dioxide captured in the carbon dioxide removal device; S9, raising the temperature of the second trap by a second heating control device until the temperature is slightly lower than the boiling point of the high-boiling-point species to remove impurities; S10, raising the temperature of the second trap until the high boiling point species is thermally desorbed, and then passing the high boiling point species into an analytical instrument for detection under the drive of the third carrier gas, thereby achieving analysis of the high boiling point species; S11, raising the temperature of the impurity removal trap by a third heating control device until the impurity gas in the impurity removal trap is thermally desorbed and discharged with the drying gas.

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