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CN-121971876-A - Gradient temperature control sealed sample pool combined multistage micro-flow cold trap system

CN121971876ACN 121971876 ACN121971876 ACN 121971876ACN-121971876-A

Abstract

The invention discloses a gradient temperature control sealed sample cell combined multistage microfluidic cold trap system which comprises a controller, a first laser, a second laser, a cold trap sample cell, a first cold trap and a second cold trap, wherein the controller is used for controlling a first laser and a second laser to emit laser and controlling temperatures of the cold trap sample cell, the first cold trap and the second cold trap, the first laser is used for heating and melting carbonate samples, the second laser is used for detecting gas concentrations in the cold trap sample cell, the first cold trap and the second cold trap, the cold trap sample cell is used for providing a carbonate sample melting environment and performing primary purification on the gas, the first cold trap and the second cold trap are used for performing deep purification on the gas, and the mass spectrometer is used for checking the gas. The invention is used for carbon-oxygen isotope analysis of laser high-temperature molten carbonate samples, can efficiently remove impurities such as water vapor, and the like, remarkably improves the gas purity and the accuracy, stability and analysis flux of isotope analysis results, and is particularly suitable for high-precision testing of precious trace samples in the fields of geology, environment and the like.

Inventors

  • HE YINJUN
  • ZHOU FUCHUN
  • LIU XINXIN
  • LU BOWEN
  • LI ZHIYONG
  • WU HAIYAN
  • TONG CHAOHUI
  • ZANG CHUNYAN
  • QI YUMIN
  • YANG JILEI
  • YAO YAQIN
  • CAI TAO
  • SONG XIUZHANG
  • YIN HONGCHAO
  • ZHENG WEI

Assignees

  • 中海油能源发展股份有限公司

Dates

Publication Date
20260505
Application Date
20260127

Claims (10)

  1. 1. A gradient temperature control sealed sample cell combined multistage microfluidic cold trap system is characterized by comprising: A controller (1) which controls the first laser and the second laser to emit laser light and controls the temperatures of the cold trap sample cell, the first cold trap and the second cold trap according to the gas concentrations in the cold trap sample cell, the first cold trap and the second cold trap; A first laser (2) which emits a first laser beam (31) and irradiates into the cold-trap sample cell (4) to heat and melt a carbonate sample in the cold-trap sample cell; A second laser (3) which emits a second laser light (32) and is respectively injected into the cold trap sample cell (4), the first cold trap (5) and the second cold trap (6) for detecting the gas concentrations in the cold trap sample cell, the first cold trap and the second cold trap; a cold trap sample cell (4) which provides a carbonate sample melting environment and performs primary purification on carbon dioxide gas generated by melting the carbonate sample; a first cold trap (5) for purifying carbon dioxide gas generated by melting a carbonate sample; A second cold trap (6) for re-purifying the carbon dioxide gas generated by melting the carbonate sample; a mass spectrometer (7) for checking carbon dioxide gas generated by melting the carbonate sample.
  2. 2. The gradient temperature control sealed sample cell combined multi-stage microfluidic cold trap system is characterized by comprising an upper cover (11), a main body (12) and a lower cover (13) which are sequentially connected from top to bottom, wherein a beam shaping mirror (19) is arranged above the upper cover (11), the main body (12) is of a sleeve structure with a cavity formed in the middle, a zinc sulfide window mirror (14) is arranged at the top, a microtube cold trap mechanism and a sample cell support (20) are arranged in the cavity, an air inlet (17) for introducing air is arranged in the middle of the bottom of the lower cover (13), the air inlet (17) is connected with a gas carrying cylinder, and the cavity walls of a sealed cavity formed by the upper cover (11), the main body (12) and the lower cover (13) are coated with light reflecting materials.
  3. 3. The gradient temperature control sealed sample cell combined multi-stage microfluidic cold trap system according to claim 1, wherein a through hole is formed in the middle of the upper cover (11).
  4. 4. The gradient temperature control sealed sample cell combined multi-stage microfluidic cold trap system according to claim 1, wherein an annular groove is formed in the middle of the top surface of the main body (12), a zinc sulfide window mirror (14) is arranged in the annular groove, a composite coating of a silicon nitride insulating layer and a copper heat conducting layer formed by magnetron sputtering is arranged on the surface of the zinc sulfide window mirror (14), and a PTC heating ring is integrated.
  5. 5. The gradient temperature control sealed sample pool combined multistage micro-flow cold trap system according to claim 2 is characterized in that an annular groove is formed in the inner wall of a cavity of a main body (12), a micro-pipe cold trap mechanism is arranged in the annular groove, the micro-pipe cold trap mechanism comprises a first micro-pipe cold trap (15) and a second micro-pipe cold trap (16) which are arranged up and down, the first micro-pipe cold trap (15) and the second micro-pipe cold trap (16) are of the same structure, spiral micro-channels are formed in pipe walls, refrigerant circulates in the spiral micro-channels, two refrigerant channels which are arranged in the radial direction are formed in the wall of the main body (12), the two refrigerant channels are respectively communicated with the spiral micro-channels of the first micro-pipe cold trap (15) and the second micro-pipe cold trap (16), an interface (10) is arranged at the position of the outer wall of the main body (12) corresponding to a refrigerant channel port, and the interface (10) is connected with a refrigerant bottle.
  6. 6. The gradient temperature control sealed sample cell combined multi-stage microfluidic cold trap system according to claim 5, wherein the sample cell support (20) is arranged between the first microtube cold trap (15) and the second microtube cold trap (16), two ends of the sample cell support (20) are inserted into the inner wall of the main body (12), and the sample cell support (20) is a porous plate.
  7. 7. The gradient temperature control sealed sample cell combined multi-stage microfluidic cold trap system according to claim 2, wherein the lower cover (13) is of a disc type structure, an outlet pipeline (18) is arranged on the wall body of the main body (12) in the radial direction, one end of the outlet pipeline (18) extends out of the main body (12), a tee joint (21) is arranged at the extending end, a first optical sensor (22) is arranged at one end port of the tee joint (21) coaxial with the outlet pipeline (18), and one end port of the tee joint (21) perpendicular to the axis of the outlet pipeline (18) is connected with the first cold trap (5).
  8. 8. The gradient temperature control sealed sample cell combined multi-stage microfluidic cold trap system according to claim 1, wherein the first cold trap (5) and the second cold trap (6) have the same structure and comprise a cold trap cell, a cold trap pipeline arranged in the cold trap cell and a light intensity detection mechanism; The cold trap pipeline is of a U-shaped structure, the inlet end of the cold trap pipeline of the first cold trap (5) and the tee joint (21) of the cold trap sample pool (4) are connected with the inlet end of the cold trap pipeline of the second cold trap (6), the light intensity detection mechanism comprises a light emitting device and a light sensor, which are arranged on two sides of the outlet end of the cold trap pipeline, the light emitting device is connected with the second laser, the light sensor detects the intensity of light emitted from the light emitting device after passing through the cold trap pipeline, and the change of the light intensity is sent to the controller (1); the mass spectrometer (7) samples from the cold trap line outlet end of the second cold trap (6).
  9. 9. A method for purifying high-temperature molten carbonate enriched carbon dioxide based on the system of one of claims 1 to 8 is characterized by comprising the following steps: S1, emitting laser through a first laser, and performing high-temperature melting on a carbonate sample in a cold trap sample cell after beam shaping to release gas containing CO 2 ; S2, primarily purifying the released gas by utilizing a micro-channel cold trap arranged in the cold trap sample pool, regulating the flow of a refrigerant by a controller, keeping the temperature of a micro-channel cold trap mechanism at-50 ℃ to-70 ℃, and condensing and removing most of water vapor; S3, monitoring the concentration of CO 2 in the cold trap sample pool through a first optical sensor, and controlling the temperature of the first cold trap to be reduced below-120 ℃ by a controller when the concentration reaches a set threshold value, so as to carry out primary deep capturing and purifying on the gas; S4, monitoring the concentration of CO 2 at the outlet of the first cold trap through a second optical sensor, and when the concentration change indicates that the first cold trap tends to be saturated, slowly increasing the temperature of the first cold trap to-80 ℃ to-100 ℃ by the controller so as to directionally migrate CO 2 to the second cold trap; S5, controlling the temperature of the second cold trap to be lower than-150 ℃, carrying out final purification on CO 2 , and monitoring the purity of the outlet gas through a third optical sensor; And S6, when the third optical sensor detects that the purity of the CO 2 reaches the sample injection requirement, the controller rapidly increases the temperature of the second cold trap to-30 ℃ to-50 ℃ so that the high-purity CO 2 gas is desorbed and conveyed to the mass spectrometer for carbon-oxygen isotope analysis.
  10. 10. The method for purifying high-temperature molten carbonate enriched carbon dioxide gas as claimed in claim 9, wherein during the preliminary purification in the step S2, a carrier gas is introduced into the cold trap sample cell, and the flow rate of the carrier gas is dynamically adjusted by the controller according to the first optical sensor signal.

Description

Gradient temperature control sealed sample pool combined multistage micro-flow cold trap system Technical Field The invention belongs to the technical field of gas purification, and particularly relates to a gradient temperature control sealed sample cell combined multistage micro-flow cold trap system. Background The carbon and oxygen isotope composition (δ 13 C and δ 18 O) of carbonate minerals is a very important geochemical index in geology, environmental science and planetary science research. They can invert the paleoclimatic environment, trace the carbon circulation process, judge diagenetic effects and explore the history of celestial body evolution. The laser high-temperature melting method is one of the mainstream technologies for extracting CO 2 gas in carbonate samples for isotope analysis at present, and the method utilizes high-energy laser beams to instantly heat the samples to a molten state, so that the samples are decomposed to release CO 2 gas, and has the remarkable advantages of high analysis precision, small sample consumption, high spatial resolution and the like. However, in the high temperature melting process, the carbonate sample may generate a certain amount of various impurity gases such as water vapor, sulfide, and nitrogen oxide in addition to the target CO 2 gas. If these impurity gases are not removed effectively, homoisobaric interference can be generated in subsequent mass spectrometry, which seriously reduces the accuracy and precision of analysis results, and even causes pollution and damage to high-sensitivity ion sources and detectors of mass spectrometers. Currently, a common purification scheme is to use a single or multiple stages of Cold traps (Cold Trap) in series to Trap impurities. The prior art has the obvious defects that (1) the purification efficiency is limited, the traditional cold trap is usually a simple U-shaped or finger-shaped pipe, the traditional cold trap is cooled integrally by means of liquid nitrogen or semiconductor refrigeration, the condensation surface area is limited, the airflow path is short, the contact with the cold wall is insufficient, the capture efficiency of impurities such as water vapor and the like is low, and particularly when the sample quantity is small or the impurity content is low, the purification effect is difficult to meet the requirement of high-precision mass spectrometry. (2) The process is blind and has poor controllability, and most of the existing systems lack real-time online monitoring of the purification process. The operator cannot know the specific concentration and purification state of the gas in the cold trap and can only rely on experience to set fixed heating, cooling times and temperature programs. The "blind operation" mode is extremely prone to two consequences, namely incomplete purification, impurity gas being brought into the mass spectrometer, and excessive purification or untimely desorption, resulting in loss of target CO 2 gas or unnecessary prolongation of analysis period. (3) The system integration level and the automation degree are low, namely the sample tank, the cold trap, the transmission pipeline and the control system are designed in a split type, and the number of connecting nodes is large, so that the leakage risk exists. And the whole flow requires more manual intervention from melting and purifying to sample injection, so that the automation and intelligent closed-loop control of the whole analysis flow are difficult to realize, and the improvement of analysis flux and the elimination of human errors are limited. Therefore, an integrated high-performance purification system is urgently needed in the field, can be tightly coupled with a laser melting sample cell, and realizes visual monitoring and intelligent feedback control on the whole process of gas generation, purification and transportation, so that the gas entering a mass spectrometer is ensured to have extremely high purity, and finally reliable technical guarantee is provided for carbon-oxygen isotope analysis. Disclosure of Invention The invention provides a gradient temperature control sealed sample cell combined multistage micro-flow cold trap system, which aims to solve the problems in the prior art. The invention is realized by the following technical scheme: A gradient temperature controlled sealed sample cell combined multi-stage microfluidic cold trap system comprising: a controller which controls the first laser and the second laser to emit laser light and controls the temperatures of the cold trap sample cell, the first cold trap and the second cold trap according to the gas concentrations in the cold trap sample cell, the first cold trap and the second cold trap; the first laser emits first laser and irradiates the first laser into the cold trap sample cell, and is used for heating and melting carbonate samples in the cold trap sample cell; The second laser emits second laser and respectively irradiates into the