Condensation pre-concentration equipment for trace organic gas and treatment method of condensation pre-concentration equipment

Abstract

The invention provides condensation and pre-concentration equipment for trace organic gas and a treatment method thereof, and the condensation and pre-concentration equipment comprises a water vapor removal device which is used for removing impurity gas mainly containing water in sample gas; the carbon dioxide removal device is used for removing carbon dioxide in the sample gas; the trapping trap device comprises a first trapping trap and a second trapping trap, and the second trapping trap is connected with the carbon dioxide removal device and is used for trapping the sample gas subjected to carbon dioxide removal; the temperature control device is used for controlling the temperature of the water vapor removal device and the trap device; the valve group device comprises a plurality of valves which are multi-channel switching valves and are at least used for introducing sample gas and dry gas; the carrier gas input device comprises a first path of carrier gas, a second path of carrier gas and a third path of carrier gas, the first path of carrier gas is used for driving a sample to transfer, the second path of carrier gas is used for driving sample gas to enter an analytical instrument for detection, and the third path of carrier gas is used for back-blowing carbon dioxide in the carbon dioxide device; and the analysis device is used for analyzing the sample gas.

Description

Technical Field

[0001] The invention relates to the field of volatile gas analysis, and in particular to a condensation pre-concentration device for trace organic gas and a processing 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 life, a wide variety, and a strong greenhouse effect. Some substances (containing chlorine, bromine and other halogen atoms) can even destroy stratospheric ozone and cause harm to human health. They are a type of substance that the world focuses on. Trace organic gases are extremely volatile, and some species have a boiling point below minus 120 degrees Celsius. They are generally captured by low temperature combined with adsorbents. Ordinary condensation pre-concentration equipment is difficult to achieve efficient capture of the above-mentioned highly volatile and extremely low-concentration species, and there is no removal of interfering species, resulting in problems such as inability to measure or low measurement accuracy. Some complex condensation pre-concentration equipment performs relatively simple water and carbon dioxide removal, which can achieve the enrichment of the above-mentioned substances, but insufficient injection volume and insufficient water removal depth lead to bottlenecks in the sensitivity and detection limit of the instrument. With the emergence of new atmospheric species such as minor CFCs and minor HCFCs in recent years, attention has been drawn. 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 pre-concentration equipment and its processing methods. Summary of the invention

[0003] The present invention is made to solve the above-mentioned problems, and aims to provide a condensation pre-concentration device for trace organic gas and a treatment method thereof.

[0004] The present invention provides a condensation pre-concentration device for trace organic gases, which has the following characteristics, including: a water vapor removal device, used for removing impurity gases mainly composed of water in sample gas; a carbon dioxide removal device, used for removing carbon dioxide in 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 capturing the sample gas after carbon dioxide is removed; a temperature control device, used for controlling the temperature 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, at least used for introducing sample gas and 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 for driving the sample gas to transfer, the second carrier gas is used for driving the sample gas to enter an analytical instrument for detection, and the third carrier gas is used for back-blowing carbon dioxide in the carbon dioxide removal device; and an analysis device, used for analyzing the sample gas.

[0005] The condensation pre-concentration equipment for trace organic gases provided by the present invention may also have the following features: wherein the water vapor removal device is connected to the dry gas inlet, and includes a de-impurity trap, a first dryer and a second dryer, the second dryer is connected to the first capture trap, and the de-impurity trap is used to remove impurity gases mainly composed of water at an extremely low temperature depth, and the extremely low temperature is -50~-70°C.

[0006] The condensation pre-concentration equipment for trace organic gases provided by the present invention may also have the following features: the dry gas inlet is controlled by an electromagnetic valve, including two routes, one of which is used to lead to the first dryer and the second dryer for preliminary water removal, and the other is used to connect to the valve group device to purge the impurity gas in the impurity trap.

[0007] In the condensation pre-concentration equipment for trace organic gases provided by the present invention, it can also have the following characteristics: wherein, 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.

[0008] The trace organic gas condensation pre-concentration equipment provided by the present invention may also have the following features: 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 are in contact with the pipeline through thermal conductive paste to measure the temperature, thereby improving the consistency and accuracy of the temperature measurement of the first trap, the second trap and the impurity removal trap.

[0009] The condensation pre-concentration equipment for trace organic gases provided by the present invention may also have the following features: it also includes a vacuum chamber, which seals the outer walls of the impurity removal trap, the first capture trap, the second capture trap, the cold plate and the refrigeration equipment and evacuates them using a vacuum pump 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 equipment due to the low temperature, thereby affecting the temperature control of the first capture trap, the second capture trap and the impurity removal trap.

[0010] In the condensation pre-concentration equipment for trace organic gases provided by the present invention, it can also have the following characteristics: wherein, 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 the valve positions is connected to a dry gas cylinder for inputting dry gas, thereby purging impurity gases captured by the impurity trap, the other three valve positions are connected to a standard gas cylinder, respectively for inputting common standard gas, spare standard gas and quality control standard gas, thereby analyzing and calculating the concentration of each species in the sample and quality control, the other valve positions are connected to a sample gas cylinder for inputting sample gas, the first valve position is connected to a sample gas cylinder for inputting sample gas, and the second valve position is connected to a sample gas cylinder for inputting 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, which is controlled by an electromagnetic valve with the first trap, the impurity removal trap and the second drying gas inlet, and includes two routes, one of which is used to lead to the first device and connected to 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 connected to the carbon dioxide removal device, the fourth valve, the fifth valve and the second carrier gas.

[0011] The condensation pre-concentration equipment for trace organic gases provided by the present invention may also have the following features: wherein 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.

[0012] The present invention also provides a processing method for a condensation pre-concentration device of trace organic gas, 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 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 the cold energy to the cold plate, and the cold plate then transfers the 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 in sequence for deep water removal, and then enters the first trap for enrichment; S3, the temperature of the first trap is increased by the first heating control device until the temperature is higher than the transfer temperature of the boiling point 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, the 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, the temperature of the second trap is increased by the second heating control device until the temperature is slightly lower than the boiling point of the low-boiling-point species, thereby removing argon, krypton, xenon, methane, and nitrogen from the sample gas. and oxygen are purged out of the pipeline, and the second carrier gas is used to back-purge the carbon dioxide captured in the carbon dioxide removal device; S5, the temperature of the second trap is increased through the second heating control device until the low-boiling-point species are thermally desorbed, and then the low-boiling-point species are passed into the analytical instrument for detection under the drive of the third carrier gas, thereby realizing the analysis of the low-boiling-point species; S6, the temperature of the first trap is increased through the 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 and low boiling-point species in the first trap is purged out of the pipeline; S7, the carbon dioxide removal device is connected to the second carrier gas, and the carbon dioxide adsorbed during the purging process is back-blown; S8, the first heating control device is used to increase the temperature of the first trap 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 and low boiling-point species in the first trap is purged out of the pipeline; The heat control device increases the temperature of the first trap until the high-boiling-point species are thermally desorbed and transferred to the second trap with the first carrier gas for enrichment, and 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 trap is increased until the temperature is slightly lower than the boiling point of the high-boiling-point species to remove impurities; S10, the temperature of the second trap is further increased until the high-boiling-point species are thermally desorbed, and then the high-boiling-point species are passed into the analytical instrument for detection under the drive of the third carrier gas, thereby realizing the analysis of the high-boiling-point species; S11, through the third heating control device, the temperature of the impurity removal trap is increased until the impurity gas in the impurity removal trap is thermally desorbed and discharged with the drying gas.

[0013] Functions and Effects of the Invention According to the condensation pre-concentration equipment and the treatment method of the trace organic gas involved in the present invention, by performing low-temperature pre-concentration of the trace organic gas and deep water removal in an independent impurity removal trap, removal of impurities such as carbon dioxide, and thermal desorption treatment, the enrichment and separation of no less than 55 species are achieved and the interference of impurities is minimized, thereby improving the detection accuracy of the above-mentioned substances. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A schematic structural diagram of a trace organic gas condensation pre-concentration device provided in an embodiment of the present invention.

[0015] Figure 2 A schematic diagram of the water removal and enrichment stage of the trace organic gas condensation pre-concentration equipment provided in an embodiment of the present invention.

[0016] Figure 3 Schematic diagram of low-boiling-point species transfer and secondary enrichment of the trace organic gas condensation pre-concentration equipment provided in an embodiment of the present invention.

[0017] Figure 4 Schematic diagram of purging impurities and back-flushing carbon dioxide after secondary enrichment of low-boiling-point species in the trace organic gas condensation pre-concentration equipment provided in an embodiment of the present invention.

[0018] Figure 5 A schematic diagram of the transfer of low-boiling-point species of the trace organic gas condensation pre-concentration equipment provided in an embodiment of the present invention to an analytical instrument and the purging of impurities before the secondary enrichment of high-boiling-point species.

[0019] Figure 6 A schematic diagram of back-flushing carbon dioxide after purging impurities before secondary enrichment of high-boiling-point species in a trace organic gas condensation pre-concentration device provided in an embodiment of the present invention.

[0020] Figure 7 Schematic diagram of high boiling point species transfer and secondary enrichment of trace organic gas condensation pre-concentration equipment provided in an embodiment of the present invention.

[0021] Figure 8 A schematic diagram of impurities purging after secondary enrichment of high boiling point species in a trace organic gas condensation pre-concentration device provided in an embodiment of the present invention.

[0022] Fig. 9 Schematic diagram of transferring high-boiling-point species from a trace organic gas condensation pre-concentration device to an analytical instrument provided in an embodiment of the present invention.

[0023] Fig.10 A schematic diagram of the purge and drainage of the impurity removal trap after all the species to be tested leave the gas path and start analysis in the trace organic gas condensation pre-concentration equipment provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0025] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the following embodiments are combined with the accompanying drawings to specifically illustrate the trace organic gas condensation pre-concentration equipment of the present invention.

[0026] Figure 1 A schematic structural diagram of a trace organic gas condensation pre-concentration device provided in an embodiment of the present invention.

[0027] like Figure 1 As shown, the trace organic gas condensation pre-concentration equipment 100 in this embodiment includes: a water vapor removal device 90, a carbon dioxide removal device 20, a capture 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.

[0028] The water vapor removal device 90 is used to remove impurity gases, mainly water, from the sample gas.

[0029] The water vapor removal device 90 is connected to the dry gas inlet, and includes a dehumidification trap, a first dryer and a second dryer.

[0030] The first dryer and the second dryer are both Nafion dehumidification tubes, which are used to remove most of the water vapor in the sample to prevent excessive water from being captured by the impurity trap and the capture trap and occupying more adsorption sites, thereby reducing the water removal capacity of the impurity trap and affecting its capture of the target. The dehumidification principle is to allow the sample gas to exchange water vapor with the dry gas, and the dry gas and sample gas flow paths are opposite.

[0031] The impurity trap is used to remove a small amount of water vapor in the sample gas that is not removed by the Nafion water removal tube. Its principle is to use extremely low temperature condensation to deeply remove water, such as -60℃, at which time the saturated vapor pressure of ice is less than 1Pa.

[0032] The first dryer is connected to the sample gas inlet. The second dryer is connected to the first trap. The impurity trap is used to remove impurity gases, mainly water, at extremely low temperatures, ranging from -50 to -70°C. Removing the interference of water vapor in the sample helps to improve the analytical sensitivity and accuracy of subsequent analytical instruments.

[0033] The dry gas inlet is controlled by a solenoid valve, which includes two routes, one of which is used to lead to the first dryer and the second dryer for preliminary water removal, and the other is used to connect with the valve group device to purge the impurity gas in the impurity trap.

[0034] The carbon dioxide removal device 20 is used to remove carbon dioxide in the sample gas.

[0035] In this embodiment, the carbon dioxide removal device 20 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.

[0036] MS4A molecular sieve is used to remove carbon dioxide from the first-stage sample gas from which water vapor has been removed. The removal principle is to allow the target to pass through without loss according to the different particle sizes of different gas molecules, while leaving most of the carbon dioxide inside the molecular sieve. The second-stage sample gas from which water and carbon dioxide have been removed will be enriched by the second trap in a low-temperature state.

[0037] The second trap is connected to the carbon dioxide removal device 20 and is used to capture the sample gas after the carbon dioxide is removed.

[0038] The temperature control device 40 is used to control the temperature of the water vapor removal device 90 and the trap device 30 .

[0039] 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 removal trap, the first trap and the second trap, the first heating control device and the second heating control device are connected to the first trap and the second trap respectively through wires, and the third heating control device is connected to the impurity removal trap.

[0040] 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.

[0041] The vacuum chamber 80 seals the impurity removal trap, the first capture trap, the second capture trap, the cold plate and the outer wall of the refrigeration equipment and uses a vacuum pump to evacuate the air to prevent a large amount of water vapor from freezing on the cold plate and the outer wall of 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.

[0042] The temperature control principle is as follows: the cold plate is connected to the cold end of the refrigeration equipment, thereby transferring cold energy to the impurity removal trap, the first capture trap and the second capture trap, so that they can be quickly cooled down and the target species can be captured. The heating control device can heat the capture trap by loading current to achieve thermal desorption of the target. In addition, the use of the vacuum chamber 80 can prevent a large amount of water vapor from condensing on the outer wall of the impurity removal trap, the first capture trap, the second capture trap, the cold plate and the cold end of the refrigeration equipment, thereby affecting the accuracy and stability of the capture trap temperature control.

[0043] The carrier gas input device 60 includes 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 back-blow the carbon dioxide in the carbon dioxide device 20, and the third carrier gas is used to drive the sample gas into the analytical instrument for detection.

[0044] The analysis device 70 is used to analyze the sample gas.

[0045] The valve group device 50 includes a plurality of valves, which specifically include 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 in the present embodiment, and are all multi-channel switching valves, which are used at least for introducing sample gas and drying gas. The various components in the pipeline are interconnected through the valve group device 50. By accurately switching each valve to a different valve position, the connection sequence of the pipeline can be switched arbitrarily to achieve different connection requirements, thereby ensuring the repeatability of the experiment.

[0046] The first valve V1 is a multi-position selector valve including ten interfaces.

[0047] Interface 1, interface 3, interface 5, interface 7 and interface 9 are connected to the sample gas cylinder for inputting sample gas. Interface 11 is connected to the dry gas cylinder for inputting dry gas, so as to purge the impurity gas captured by the impurity trap. Interface 17 is connected to air for inputting air. Interface 13, interface 15 and interface 19 are connected to the standard gas cylinder 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.

[0048] The second valve V2 is a multi-way two-position valve including six interfaces.

[0049] Among them, interface 1 is connected to the MFC inlet pressure sensor, filter, MFC and vacuum pump in sequence, and interface 2 is connected to the first dryer, sample inlet pressure sensor, pressure regulating valve and sample gas inlet in sequence, wherein MFC is a flow controller for controlling the inlet flow of sample gas.

[0050] The third valve V3 is an irregular valve including six interfaces.

[0051] Among them, interface 1 is connected to the impurity removal trap and interface 4 in sequence, interface 2 is connected to the second dryer, the first capture trap and interface 5 in sequence, and is used to enrich 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.

[0052] The fourth valve V4 is a multi-way two-position valve including four interfaces.

[0053] The interface 3 is connected to the first carrier gas to drive the sample transfer, and the interface 4 is connected to the interface 5 of the second valve V2.

[0054] 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 point species), which helps to improve the analysis accuracy of the species to be tested in the second transfer.

[0055] The fifth valve V5 is an irregular valve including six interfaces.

[0056] Among them, interface 1 is connected to the differential pressure sensor and the trap flowmeter in sequence, interface 2 is connected to the second trap and interface 5 in sequence, and interface 3 is connected to the third carrier gas, thereby driving the sample gas into the analytical instrument for detection.

[0057] The sixth valve V6 is a multi-way two-position valve including ten interfaces.

[0058] Among them, interface 1 is connected to interface 4 of the fifth valve V5, interface 2 is connected to the analysis device 70 in sequence, interface 3 is connected to the analysis device 70 and interface 10, interface 4 is connected to the second carrier gas, so as to back-blow the carbon dioxide in the carbon dioxide removal device 20, interface 5 is connected to the column back-blow flowmeter, interface 6 is connected to the carbon dioxide removal device 20 and interface 9 in sequence, 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.

[0059] The sixth valve V6 is used to control the flow direction of the carrier gas in the carbon dioxide removal device 20 (carbon dioxide removal or backwashing), and at the same time control the connection state between the sample gas and the subsequent analytical instrument.

[0060] In this embodiment, the second valve V2 has two valve positions when working: Valve position A: port 2 is connected to port 3, port 4 is connected to port 5, and port 6 is connected to port 1.

[0061] Valve position B: port 1 is connected to port 2, port 3 is connected to port 4, and port 5 is connected to port 6.

[0062] The third valve V3 has three valve positions when working: Valve position 1: port 1 is connected to port 6, and port 3 is connected to port 4.

[0063] Valve position 3: port 2 is connected to port 3, and port 5 is connected to port 6.

[0064] Valve position 12: port 1 is connected to port 2, port 3 is connected to port 4, and port 5 is connected to port 6.

[0065] The fourth valve V4 has two valve positions when working: Valve position A: port 1 is connected to port 2, and port 3 is connected to port 4.

[0066] Valve position B: port 2 is connected to port 3, and port 1 is connected to port 4.

[0067] The fifth valve V5 has three valve positions when working: Valve position 1: port 3 is connected to port 4, and port 6 is connected to port 1.

[0068] Valve position 2: port 2 is connected to port 3, port 4 is connected to port 5, and port 6 is connected to port 1.

[0069] Valve position 12: port 1 is connected to port 2, port 3 is connected to port 4, and port 5 is connected to port 6.

[0070] The sixth valve V6 has two valve positions when working: Valve position A: port 2 is connected to port 3, port 4 is connected to port 5, port 6 is connected to port 7, port 8 is connected to port 9, and port 10 is connected to port 1.

[0071] 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.

[0072] 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, connected to the impurity removal trap, connected to the second dryer, connected to the first trap, and connected to the MFC.

[0073] In the analysis stage: the first trap is connected to the carbon dioxide removal device 20 , connected to the second trap, and connected to the analysis device 70 .

[0074] Figure 2 A schematic diagram of the water removal and enrichment stage of the trace organic gas condensation pre-concentration equipment provided in an embodiment of the present invention. Figure 3 Schematic diagram of low-boiling-point species transfer and secondary enrichment of the trace organic gas condensation pre-concentration equipment provided in an embodiment of the present invention. Figure 4 Schematic diagram of purging impurities and back-flushing carbon dioxide after secondary enrichment of low-boiling-point species in the trace organic gas condensation pre-concentration equipment provided in an embodiment of the present invention. Figure 5 A schematic diagram of the transfer of low-boiling-point species of the trace organic gas condensation pre-concentration equipment provided in an embodiment of the present invention to an analytical instrument and the purging of impurities before the secondary enrichment of high-boiling-point species. Figure 6 A schematic diagram of back-flushing carbon dioxide after purging impurities before secondary enrichment of high-boiling-point species in a trace organic gas condensation pre-concentration device provided in an embodiment of the present invention. Figure 7 Schematic diagram of high boiling point species transfer and secondary enrichment of trace organic gas condensation pre-concentration equipment provided in an embodiment of the present invention. Figure 8 A schematic diagram of impurities purging after secondary enrichment of high boiling point species in a trace organic gas condensation pre-concentration device provided in an embodiment of the present invention. Fig. 9 Schematic diagram of transferring high-boiling-point species from a trace organic gas condensation pre-concentration device to an analytical instrument provided in an embodiment of the present invention. Fig.10 A schematic diagram of the purge and drainage of the impurity removal trap after all the species to be tested leave the gas path and start analysis in the trace organic gas condensation pre-concentration equipment provided in an embodiment of the present invention.

[0075] In this embodiment, the processing method of the condensation pre-concentration device 100 for trace organic gas specifically includes the following steps: S1, such as Figure 2 As 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 energy to the cold plate, and the cold plate transfers the cold energy to the impurity removal trap, the first trap and the second trap, so that the temperature of the impurity removal trap, the first trap and the second trap is reduced to -165°C.

[0076] S2, according to Figure 2 As shown by the arrow in the middle, the sample gas enters the pipeline through the first valve V1, passes through the -60°C impurity removal trap, the first dryer and the second dryer for deep water removal, and then enters the first capture trap for enrichment.

[0077] S3, such as Figure 3 As shown, according to Figure 3 In the gas path indicated by the middle 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. The temperature of the first trap is increased by the first heating control device until the temperature is higher than the transfer temperature of the boiling point of the low-boiling point species in the sample gas, and the low-boiling point 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, and then the low-boiling point species and the first carrier gas are transferred to the second trap for enrichment.

[0078] S4, such as Figure 4 As shown, according to Figure 4 In the gas path indicated by the middle 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. The temperature of the second trap is increased by the second heating control device until the temperature is slightly lower than the boiling point of the low-boiling-point species, so that the argon, krypton, xenon, methane, nitrogen and oxygen in the sample gas are purged out of the pipeline (the gas path indicated by the first arrow), and at the same time, the second carrier gas back-purges the carbon dioxide captured in the carbon dioxide device 20 (the gas path indicated by the second arrow).

[0079] S5, such as Figure 5 As shown (the gas path shown 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. The temperature of the second trap is increased by the second heating control device until the low-boiling-point species are thermally desorbed, and then the low-boiling-point species are passed into the analytical instrument for detection under the drive of the third carrier gas, thereby realizing the analysis of the low-boiling-point species.

[0080] Generally, the purge temperature of the low boiling point 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.

[0081] S6, such as Figure 5 As shown (the fourth arrow indicates the gas path), 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. The temperature of the first trap is increased by the 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.

[0082] S7, such as Figure 6 As shown, according to Figure 6 In the gas path indicated by the middle 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. The carbon dioxide removal device 20 is connected to the second carrier gas back-flushing and purging process to absorb carbon dioxide.

[0083] S8, such as Figure 7 As shown, according to Figure 7In the gas path indicated by the middle 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. The temperature of the first trap is increased by the 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-blows the carbon dioxide captured in the carbon dioxide device 20.

[0084] S9, such as Figure 8 As shown, according to Figure 8 In the gas path indicated by the middle 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. The temperature of the second trap is increased by the second heating control device until the temperature is slightly lower than the boiling point of the high-boiling-point species to remove impurities.

[0085] S10, such as Fig. 9 As shown, according to Fig. 9 In the gas path indicated by the middle 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. The temperature of the second trap is further increased until the high boiling point species are thermally desorbed, and then the high boiling point species are passed into the analytical instrument for detection under the drive of the third carrier gas, thereby realizing the analysis of the high boiling point species.

[0086] S11, such as Fig.10 As shown, according to Fig.10 In the gas path indicated by the middle 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. MFC is set to a suitable value, and the temperature of the impurity removal trap is increased through the third heating control device until the impurity gas in the impurity removal trap is thermally desorbed and discharged with the dry gas.

[0087] Generally, the purge temperature of the high boiling point 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.

[0088] Functions and Effects of the Embodiments According to the condensation pre-concentration equipment and the treatment method of the trace organic gas involved in the present invention, by performing low-temperature pre-concentration of the trace organic gas and deep water removal in an independent impurity removal trap, removal of impurities such as carbon dioxide, and thermal desorption treatment, the enrichment and separation of no less than 55 species are achieved and the interference of impurities is minimized, thereby improving the detection accuracy of the above-mentioned substances.

[0089] The present invention increases the sample injection volume and adds a separate impurity removal trap, and measures the temperature by contacting the thermocouple temperature measuring point with the pipeline through thermal conductive paste, thereby greatly improving the precision and accuracy of the analysis.

[0090] Under -60°C conditions, the present invention effectively removes water vapor caused by large-volume injection and hindering high-precision and high-sensitivity detection through the precise control of a newly added irregular valve and a heating control device and a flow control device, thereby improving the sensitivity and detection limit of the analytical instrument while meeting the requirements of a large injection volume and maximally removing water and carbon dioxide.

[0091] The present invention optimizes the temperature control system, enhances the cooling efficiency between the capture trap and the impurity removal trap and the refrigeration end, reduces heat loss, and improves the speed, accuracy and stability of temperature control.

[0092] Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached 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 is used to analyze the sample gas.

2. The condensation pre-concentration device for trace organic gases according to claim 1, characterized in that: in, The water vapor removal device is connected to the dry gas inlet, and includes a de-impurity trap, a first dryer and a second dryer, wherein the second dryer is connected to the first capture trap, and the de-impurity trap is used to remove impurity gases mainly composed of water at an extremely low temperature depth, wherein the extremely low temperature is -50~-70°C.

3. The condensation pre-concentration device for trace organic gases according to claim 2, characterized in that: in, 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 for preliminary water removal, and the other is used to connect with the valve group device to purge the impurity gas in the impurity removal trap.

4. The condensation pre-concentration device for trace organic gases according to claim 2, characterized in that: in, 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.

5. The condensation pre-concentration device for trace organic gases according to claim 4, 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.

6. The condensation pre-concentration equipment for trace organic gases according to claim 4, 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.

7. The condensation pre-concentration device for trace organic gases according to claim 4, 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.

8. 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.

9. A method for treating a trace organic gas condensation pre-concentration device according to any one of claims 1 to 8, 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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