CN-121384860-B - Method and device for detecting mixed gas characteristic decomposition product heat release reactance interference

CN121384860BCN 121384860 BCN121384860 BCN 121384860BCN-121384860-B

Abstract

The invention relates to a method and a device for detecting mixed gas characteristic decomposition product heat release reactance interference, belonging to the field of insulating gas detection. The method comprises the steps of feeding sample gas into a chromatographic column through carrier gas, enabling first product gas to flow into a detection cavity through a buffer tank, obtaining first concentration of the first product gas through carrier gas flushing, vacuumizing the detection cavity to obtain second concentration of the first product gas, obtaining third concentration of the first product gas through further carrier gas flushing, obtaining first to third concentrations of the second product gas and the third product gas in the same way, and obtaining final concentrations of the second product gas and the third product gas respectively based on the first to third concentrations of each product gas. According to the method, different characteristic product gases are output to the corresponding buffer tanks in a time-sharing manner through a chromatography method, then the sample gas is conveyed through carrier gas, and detection is carried out through the corresponding pyroelectric detector, so that the problem that the characteristic product gases directly use a spectroscopic method to detect the mutual infrared absorption wave bands and the background gas are cross-interfered is solved.

Inventors

DING WUXING
WANG JIANXIN

Assignees

泰普联合科技开发(合肥)有限公司

Dates

Publication Date: 20260512
Application Date: 20251225

Claims (4)

1. The method for detecting the heat release reactance interference of the characteristic decomposition product of the mixed gas is characterized by comprising the following steps of: loading carrier gas into a chromatographic column, heating the chromatographic column to a preset temperature, vacuumizing a buffer tank, a detection cavity and related pipelines, loading sample gas into a quantitative ring, and sending the sample gas in the quantitative ring into the chromatographic column through the carrier gas; Flowing the first product gas into the detection cavity through the buffer tank, and flushing by carrier gas to obtain a first concentration of the first product gas; specifically, according to the time period when the first product gas flows out of the chromatographic column, the first product gas flows into the first detection cavity through the first buffer tank, and the first product gas remained in the first buffer tank is sent into the first detection cavity through the carrier gas; the method comprises the steps of starting an infrared light source, a first pyroelectric detector arranged in a first detection cavity and a second pyroelectric detector arranged in a second detection cavity, obtaining voltage corresponding to the first product gas through the first pyroelectric detector, obtaining reference voltage of the first product gas through the second pyroelectric detector, subtracting the voltage corresponding to the first product gas from the reference voltage to obtain a difference voltage, finding the concentration corresponding to the difference voltage on a built-in concentration calibration curve of the first product gas, and taking the concentration as the first concentration of the first product gas, wherein an optical filter of the first pyroelectric detector only allows infrared light of a wave band which can be absorbed by the first product gas and the third product gas to pass through, and an optical filter of the second pyroelectric detector only allows infrared light of the wave band which can be absorbed by the second optical filter product gas to pass through; The method comprises the steps of vacuumizing a detection cavity to obtain a second concentration of first product gas, starting a vacuum pump to vacuumize the first detection cavity to a preset vacuum degree, obtaining a voltage corresponding to the first product gas after vacuumizing through a first pyroelectric detector, obtaining a reference voltage of the first product gas through a second pyroelectric detector, subtracting the voltage corresponding to the first product gas after vacuumizing from the reference voltage to obtain a differential voltage, finding the differential voltage corresponding to the differential voltage on a built-in concentration calibration curve of the first product gas, taking the concentration as the second concentration of the first product gas, enabling the second product gas to flow into the detection cavity through a buffer tank, obtaining a third concentration of the first product gas and the first concentration of the second product gas through carrier gas flushing, enabling the second product gas to flow into the first detection cavity through a second buffer tank according to a time period when the second product gas flows out of a chromatographic tower, enabling the carrier gas to flow into the first detection cavity through the first buffer tank, the second buffer tank, obtaining the differential voltage corresponding to the first detection cavity, enabling the second product gas to flow into the second detection cavity, obtaining the second concentration of the first product gas through the first buffer tank, and the second buffer tank, and enabling the residual concentration of the first product gas to flow into the first detection cavity through the first buffer tank and the second buffer tank; The method comprises the steps of starting an infrared light source, a first pyroelectric detector and a second pyroelectric detector, obtaining voltage corresponding to the current moment s of first product gas through the first pyroelectric detector, obtaining reference voltage of the current moment s of the first product gas through the second pyroelectric detector, subtracting the voltage corresponding to the current moment of the first product gas from the reference voltage to obtain voltage after the current moment is worse, finding the concentration corresponding to the voltage after the current moment is worse on a built-in concentration calibration curve of the first product gas, taking the concentration as the concentration of the current moment of the first product gas, and obtaining the third concentration of the first product gas through the following formula: , Wherein, the Representing a third concentration of the first product gas, Indicating the concentration of the first product gas at the current time, Indicating the length of the first detection chamber, Representing the cross-sectional area of the first detection chamber, Indicating the flow rate of the carrier gas, Indicating the time for which a unit volume of gas remains in the first detection chamber; Obtaining a voltage corresponding to the second product gas through a second pyroelectric detector, obtaining a reference voltage of the second product gas through a first pyroelectric detector, subtracting the voltage corresponding to the second product gas from the reference voltage to obtain a difference voltage, finding a concentration corresponding to the difference voltage on a built-in concentration calibration curve of the second product gas, and taking the concentration as a first concentration of the second product gas; The method comprises the steps of vacuumizing a detection cavity to obtain a second concentration of second product gas, starting a vacuum pump to vacuumize the first detection cavity and the second detection cavity to a preset vacuum degree to obtain the second concentration of the second product gas, obtaining a voltage corresponding to the second product gas after vacuumizing through a second pyroelectric detector, obtaining a reference voltage of the second product gas through a first pyroelectric detector, subtracting the voltage corresponding to the second product gas after vacuumizing from the reference voltage to obtain a differential voltage, finding the concentration corresponding to the differential voltage on a built-in concentration calibration curve of the second product gas, and taking the concentration as the second concentration of the second product gas; Flowing the third product gas into the detection cavity through the buffer tank, and flushing by carrier gas to obtain the first concentration of the third product gas; according to the time period of the third product gas flowing out of the chromatographic column, the third product gas flows into the first detection cavity through the first buffer tank, and the third product gas remained in the first buffer tank is sent into the first detection cavity through carrier gas; obtaining a first concentration of third product gas through a pyroelectric detector and a concentration calibration curve, specifically obtaining a voltage corresponding to the third product gas through the first pyroelectric detector, obtaining a reference voltage of the third product gas through a second pyroelectric detector, subtracting the voltage corresponding to the third product gas from the reference voltage to obtain a difference-made voltage, finding a concentration corresponding to the difference-made voltage on the built-in concentration calibration curve of the third product gas, and taking the concentration as the first concentration of the third product gas; the method comprises the steps of vacuumizing a detection cavity to obtain a second concentration of third product gas, starting a vacuum pump to vacuumize the first detection cavity to a preset vacuum degree to obtain the second concentration of the third product gas, obtaining a voltage corresponding to the third product gas after vacuumizing through a first pyroelectric detector, obtaining a reference voltage of the third product gas through a second pyroelectric detector, subtracting the voltage corresponding to the third product gas after vacuumizing from the reference voltage to obtain a difference-made voltage, finding the concentration corresponding to the difference-made voltage on a built-in concentration calibration curve of the third product gas, and taking the concentration as the second concentration of the third product gas; The method comprises the steps of flushing by further carrier gas to obtain a third concentration of a second product gas and a third concentration of a third product gas, opening corresponding electromagnetic valves, starting vacuum pumps, pumping the carrier gas to a first detection cavity and a second detection cavity through a first buffer tank and a second buffer tank, enabling the carrier gas to flow through the first buffer tank and the second buffer tank, enabling the second product gas and the third product gas remained in the first buffer tank and the second buffer tank to be further desorbed and sent into the first detection cavity, and then flowing into the second detection cavity through the first detection cavity, obtaining the third concentration of the second product gas and the third concentration of the third product gas through a pyroelectric detector and a concentration calibration curve, Obtaining the voltage corresponding to the current moment s of the third product gas through a first pyroelectric detector, obtaining the reference voltage of the current moment s of the third product gas through a second pyroelectric detector, subtracting the voltage corresponding to the current moment of the third product gas from the reference voltage to obtain the voltage after the difference of the current moment, finding the concentration corresponding to the voltage after the difference of the current moment on a built-in concentration calibration curve of the third product gas, and taking the concentration as the concentration of the current moment s of the third product gas, and obtaining the third concentration of the third product gas through the following formula: , Wherein, the Representing a third concentration of a third product gas, Indicating the concentration of the third product gas at the current time; Obtaining the voltage corresponding to the current moment s of the second product gas through a second pyroelectric detector, obtaining the reference voltage of the second product gas at the current moment through a first pyroelectric detector, subtracting the voltage corresponding to the current moment of the second product gas from the reference voltage to obtain the voltage after the difference at the current moment, finding the concentration corresponding to the voltage after the difference at the current moment on a built-in concentration calibration curve of the second product gas, and taking the concentration as the concentration of the second product gas at the current moment: , Wherein, the Representing a third concentration of the second product gas, Indicating the concentration of the second product gas at the current time; Respectively obtaining the final concentration of each product gas based on the first concentration, the second concentration and the third concentration; the final concentration of the first product gas is obtained by the following formula: ; the final concentration of the second product gas is obtained by the following formula: ; the final concentration of the third product gas is obtained by the following formula: 。
2. a mixed gas characteristic decomposition product pyroelectric interference detection device for realizing the mixed gas characteristic decomposition product pyroelectric interference detection method of claim 1, wherein said device comprises: The six-way valve (1) is used for switching on a target gas path by switching an internal valve, and is connected with a carrier gas outlet, a sample gas outlet, a quantitative ring (2) and the top side inlet of the chromatographic column (5) through pipelines; A quantitative ring (2) for quantitative gas taking; The chromatographic column (5) is internally provided with a chromatographic agent and is used for enabling product gases of different components in the sample gas to flow out at different times; the buffer tank is used for buffering gas and is connected with the chromatographic column, the carrier gas outlet, the vacuum pump (18) and the detection device through pipelines; The vacuum pump (18) is connected with the buffer tank and the detection device through pipelines and is used for vacuumizing the buffer tank to pump gas in the buffer tank to the detection device or vacuumizing the detection device to empty gas in the detection device; a detection device for measuring the concentration of the product gas; The outer wall of the chromatographic column is provided with a first heater (6) which is used for heating the chromatographic column to a preset temperature and keeping the chromatographic column at the temperature, and the buffer tank comprises a first buffer tank (12) and a second buffer tank (13); the detection device comprises an infrared light source (22), a first detection cavity (23), a second detection cavity (24), a first pyroelectric detector (27), a second pyroelectric detector (28) and a vacuum gauge (31); The infrared light source is positioned on the bottom surface of one side of the detection device and used for providing stable infrared light, the first pyroelectric detector is positioned on the bottom surface of the other side of the first detection cavity, the optical filter of the first pyroelectric detector only allows infrared light of a wave band which can be absorbed by the first product gas and the third product gas to pass through and is used for measuring voltages corresponding to the first product gas and the third product gas, the second pyroelectric detector is positioned on the bottom surface of the other side of the second detection cavity, the optical filter of the second pyroelectric detector only allows infrared light of a wave band which can be absorbed by the second product gas to pass through and is used for measuring voltages corresponding to the second product gas, the first detection cavity is communicated with the second detection cavity through an electromagnetic valve, and the vacuum gauge is used for detecting the vacuum degree of the detection cavity.
3. The device for detecting the interference of the heat release reactance of the characteristic decomposition product of the mixed gas according to claim 2, further comprising first to third exhaust ports, wherein the first exhaust port is connected with the six-way valve through a pipeline, the second exhaust port is connected with the chromatographic column through a pipeline, and the third exhaust port is connected with the vacuum pump through a pipeline.
4. The mixed gas characteristic decomposition product pyroelectric interference detection device according to claim 2, wherein a partition plate is positioned between the first detection cavity and the second detection cavity for separating the first detection cavity and the second detection cavity from each other, and a second heater (26) is arranged on the outer walls of the first detection cavity and the second detection cavity for heating the first detection cavity and the second detection cavity to a preset temperature during detection and keeping the first detection cavity and the second detection cavity at the temperature.

Description

Method and device for detecting mixed gas characteristic decomposition product heat release reactance interference Technical Field The invention relates to the technical field of insulating gas detection, in particular to a method and a device for detecting mixed gas characteristic decomposition product heat release reactance interference. Background The electric power industry is increasingly widely adopting C 4F7N/CO2 mixed gas with good environment-friendly property to replace the traditional strong greenhouse gas SF 6 to serve as an insulating medium of electric equipment. In practical application, detecting the concentration of the characteristic product gas of the C 4F7N/CO2 mixed gas has important significance for fault diagnosis of partial discharge, overheat and the like of electrical equipment. Typical characteristic product gases of the C 4F7N/CO2 mixed gas include CF 4, CO, and C 3F8. Currently, gas chromatography is mainly adopted for analysis of C 4F7N/CO2 product gas in a laboratory, but the detection time of the method is long (about 40 minutes), so that the requirement of on-site rapid detection is difficult to meet. The on-site detection method for SF 6 product gas mainly comprises an electrochemical method and a spectroscopic method, however, the chemical properties of CF 4 and C 3F8 are relatively stable, oxidation-reduction reaction is difficult to occur, and the method is not suitable for detecting the SF 6 product gas by adopting the electrochemical method. The spectrometry has good application prospect due to high response speed and high detection precision, but the infrared absorption wave bands of CF 4 and C 3F8 are crossed, and the infrared absorption wave bands of CF 4, CO and C 3F8 are overlapped with the background gas C 4F7N、CO2, so that the concentration error of the characteristic product gas of C 4F7N/CO2 is larger by directly adopting the spectrometry. Therefore, the quick and anti-interference detection method and device for the characteristic product gas of the C 4F7N/CO2 mixed gas, which can be applied to the field, are the problems to be solved. Disclosure of Invention In view of the above analysis, the present invention aims to provide a method and a device for detecting the thermal-release reactance interference of a characteristic decomposition product of a mixed gas, which are used for solving the problem of lack of a method and a device for detecting the characteristic product gas of a C 4F7N/CO2 mixed gas which can be applied to the field at present. The invention provides a method and a device for detecting the heat release reactance interference of a characteristic decomposition product of mixed gas, wherein the method comprises the following steps: loading carrier gas into a chromatographic column, heating the chromatographic column to a preset temperature, vacuumizing a buffer tank, a detection cavity and related pipelines, loading sample gas into a quantitative ring, and sending the sample gas in the quantitative ring into the chromatographic column through the carrier gas; The first product gas flows into the detection cavity through the buffer tank, and the first concentration of the first product gas is obtained through flushing by carrier gas; Flowing the second product gas into the detection cavity through the buffer tank, and flushing by carrier gas to obtain a third concentration of the first product gas and a first concentration of the second product gas; Flowing the third product gas into the detection cavity through the buffer tank, and flushing by carrier gas to obtain the first concentration of the third product gas; the detection cavity is vacuumized to obtain the second concentration of the third product gas, and the third concentration of the second product gas and the third concentration of the third product gas are obtained through further carrier gas flushing; the final concentrations are obtained based on the first concentration, the second concentration, and the third concentration of each product gas, respectively. Further, the step of enabling the first product gas to flow into the detection cavity through the buffer tank and the step of flushing by the carrier gas to obtain the first concentration of the first product gas comprises the steps of enabling the first product gas to flow into the first detection cavity through the first buffer tank according to the time period of the first product gas flowing out of the chromatographic tower, enabling the first product gas to be fed into the first detection cavity through the carrier gas, and obtaining the first concentration of the first product gas through the pyroelectric detector and the concentration calibration curve. The method comprises the steps of starting an infrared light source, a first pyroelectric detector arranged in a first detection cavity and a second pyroelectric detector arranged in a second detection cavity, wherein an optical filter of the first pyroelectric detector