CN117630217A - Method and device for detecting methanol content in supercritical carbon dioxide - Google Patents
Method and device for detecting methanol content in supercritical carbon dioxide Download PDFInfo
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- CN117630217A CN117630217A CN202311613592.XA CN202311613592A CN117630217A CN 117630217 A CN117630217 A CN 117630217A CN 202311613592 A CN202311613592 A CN 202311613592A CN 117630217 A CN117630217 A CN 117630217A
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- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 title claims abstract description 129
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 title claims abstract description 84
- 229910002092 carbon dioxide Inorganic materials 0.000 title claims abstract description 42
- 239000001569 carbon dioxide Substances 0.000 title claims abstract description 42
- 238000000034 method Methods 0.000 title claims abstract description 35
- 238000005070 sampling Methods 0.000 claims abstract description 55
- 238000001514 detection method Methods 0.000 claims abstract description 26
- 239000012535 impurity Substances 0.000 claims abstract description 21
- 238000010438 heat treatment Methods 0.000 claims abstract description 12
- 239000007789 gas Substances 0.000 claims description 41
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 10
- 229910052739 hydrogen Inorganic materials 0.000 claims description 10
- 239000001257 hydrogen Substances 0.000 claims description 10
- 238000004587 chromatography analysis Methods 0.000 claims description 8
- 238000007599 discharging Methods 0.000 claims description 8
- 239000012159 carrier gas Substances 0.000 claims description 5
- 238000002347 injection Methods 0.000 claims description 5
- 239000007924 injection Substances 0.000 claims description 5
- 239000002912 waste gas Substances 0.000 claims description 2
- 238000005259 measurement Methods 0.000 abstract description 6
- 229910000831 Steel Inorganic materials 0.000 description 21
- 239000010959 steel Substances 0.000 description 21
- 239000007787 solid Substances 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 5
- 239000007788 liquid Substances 0.000 description 5
- 238000002474 experimental method Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 208000001034 Frostbite Diseases 0.000 description 3
- 238000002309 gasification Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 238000005303 weighing Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 238000012113 quantitative test Methods 0.000 description 1
- 238000005057 refrigeration Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000003815 supercritical carbon dioxide extraction Methods 0.000 description 1
- 230000009897 systematic effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/54—Improvements relating to the production of bulk chemicals using solvents, e.g. supercritical solvents or ionic liquids
Abstract
The invention discloses a method and a device for detecting the content of methanol in supercritical carbon dioxide, wherein the method comprises the following steps: (1) sampling: collecting supercritical carbon dioxide containing methanol by using a sampler with impurity treatment function; (2) phase change treatment: carrying out phase-changing steady-state treatment on the sample collected in the step 1) by using a sample processor; firstly, vacuumizing a sample processor until the pressure is-0.2 to-0.6 kpa; then heating the sample processor for 10-30 minutes at 110-140 ℃; then, conveying the sample in the sampler to a sample processor until the pressure is 0.2-0.6 kpa, stopping conveying the sample, and preserving heat at 110-140 ℃ for 5-10 min; (3) And conveying the sample subjected to the phase-change steady-state treatment to a gas chromatograph through a pipeline for detection. By the detection method, the supercritical carbon dioxide containing methanol can be converted into a stable state and then detected, so that the safety operation risk in the detection process can be reduced, and meanwhile, the accuracy and the reliability of the measurement result are improved.
Description
Technical Field
The invention relates to the technical field of determination of methanol content in supercritical carbon dioxide, in particular to a method and a device for detecting the methanol content in supercritical carbon dioxide.
Background
When the produced product contains a large amount of methanol mixture and the supercritical carbon dioxide extraction process is needed, the extraction effect can be characterized by measuring the methanol content in the methanol mixture, and the production process can be guided to control and adjust parameters so as to improve the product quality. The supercritical state of carbon dioxide is a mixed state between a gaseous state and a liquid state, the stable state of a sample is not easy to obtain, and if the state of the sample is unstable, the content of the whole sample occupied by the methanol to be detected is continuously changed, so that the detection result is distorted and the production operation is misled. Therefore, before measuring the methanol content in supercritical carbon dioxide, the sample needs to be packaged, stored and safely processed before detection to obtain a stable sample.
The general processing mode in the prior art is as follows: introducing supercritical carbon dioxide containing methanol into a soft rubber bladder to gasify at normal temperature and normal pressure to obtain a sample in a stable state, and then introducing the obtained sample into a gas chromatograph to detect. However, in the actual gasification process at normal temperature, the methanol component (boiling point 64.7 ℃ C., liquid state at normal temperature) is not completely converted into the gas phase, which results in a change of the methanol component in the original sample, the sample after gasification is not represented in the original sample, and the detection result is inaccurate. The supercritical carbon dioxide pressure is 14-15mpa and is in a gas-liquid mixed state during actual production, the obtained sample is directly gasified at normal temperature and normal pressure in the conventional operation, the sample can be gasified and refrigerated to form a solid state to block the outlet of the sampler at the moment of entering the soft rubber bladder, the solid carbon dioxide is gasified in the soft rubber bladder, the excessive air pressure in the soft rubber bladder can be caused, the person is swelled and burst injured, and the sprayed solid is easy to cause frostbite of the person.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a method for detecting the content of methanol in supercritical carbon dioxide, which solves the technical problems of inaccurate detection result and safety risk in the prior art for detecting the content of methanol in supercritical carbon dioxide.
Furthermore, the invention also provides a detection device for realizing the method.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a method for detecting the content of methanol in supercritical carbon dioxide comprises the following steps:
(1) Sampling: collecting supercritical carbon dioxide containing methanol by using a sampler with impurity treatment function;
(2) And (3) phase-change steady-state treatment: carrying out phase-changing steady-state treatment on the sample collected in the step 1) by using a sample processor; firstly, vacuumizing a sample processor until the pressure is-0.2 to-0.6 kpa; then heating the sample processor for 10-30 minutes at 110-140 ℃; then, conveying the sample in the sampler to a sample processor until the pressure is 0.2-0.6 kpa, stopping conveying the sample, and preserving heat at 110-140 ℃ for 5-10 min;
(3) And (3) detection: and conveying the sample subjected to the phase-change steady-state treatment to a gas chromatograph through a pipeline for detection.
Further, the sampler includes a sampling tank into which air for chromatography is introduced to remove impurity gas before the sample is fed. Therefore, the purity of the collected sample can be further improved, and impurity gas left in the last experiment is prevented from entering a sampling system.
Further, the gas chromatograph operating conditions are:
chromatographic column: a restek Stadilwax 32m x 0.53mm x 1 μm capillary chromatography column;
a detector: a hydrogen flame ionization detector;
sample inlet temperature: 180-220 ℃;
column box temperature: 110-140 ℃;
split ratio: 35-40:1;
split flow rate: 110-140 ml/min;
detecting the temperature: 230 ℃;
carrier gas: n (N) 2 The flow rate is 30ml/min;
hydrogen flow rate: 40ml/min;
air flow rate: 400ml/min;
sample injection amount: 20-40 mul.
The device for detecting the methanol content in the supercritical carbon dioxide comprises a gas chromatograph, a sample processor and a detector, wherein the gas chromatograph is used for realizing the detection method, and the sample processor is used for carrying out phase-change steady-state treatment on the supercritical carbon dioxide and comprises a body, a suction filter and a heater; the suction filter is arranged on the body through a pipeline, and the heater is arranged outside the body by adopting a heating sleeve structure; the body is also provided with a thermometer and a pressure gauge; the body is a high temperature and pressure resistant container; and the discharge port of the sample processor is connected with the feed port of the gas chromatograph.
Further, the device also comprises a sampler with the function of impurity treatment; the sampler comprises a sampling tank, a bypass pipeline is arranged between a feeding pipe and a discharging pipe of the sampling tank, valves are arranged on the feeding pipe and the discharging pipe, and a bypass valve is further arranged on the bypass pipeline; the tail end of the discharging pipe is provided with a three-way valve which is respectively connected with the waste gas collection tank and the feed inlet of the sample processor.
Compared with the prior art, the invention has the following beneficial effects:
the supercritical carbon dioxide is subjected to phase-change steady-state treatment by adopting the detection method and the device, so that a stable gaseous sample is obtained, the situation that the supercritical carbon dioxide is directly gasified at normal temperature and normal pressure to cause carbon dioxide gasification refrigeration to form a solid to block the outlet of the sampler, and meanwhile, the solid carbon dioxide is gasified in the soft rubber bladder to cause excessive air pressure in the soft rubber bladder to swell and explode to hurt people, and meanwhile, the sprayed solid causes frostbite of people is avoided, so that the safety operation risk in the detection process is reduced. Meanwhile, the methanol in the sample processed by the sample processor can be gasified completely, so that the accuracy and reliability of the measurement result are improved.
Drawings
FIG. 1 is a process flow chart and a schematic diagram of an apparatus for detecting the presence of a sample;
FIGS. 2-4 are gas chromatograms of methanol content obtained by detection using the detection method and apparatus of the present invention;
FIGS. 5 to 7 are gas chromatograms of methanol content detected by the comparative example method.
In the figure, a sampler 1, a sample processor 2, a gas chromatograph 3, a sampling tank 11, a feed pipe 12, a discharge pipe 13, a bypass pipe 14, a bypass valve 15, a three-way valve 16, an exhaust gas collection tank 17, a body 21, a pressure gauge 22, a suction filter 23, a heater 24, and a thermometer 25.
Detailed Description
The following describes the embodiments of the present invention in further detail with reference to specific examples.
Numerical ranges in this disclosure are understood to also specifically disclose each intermediate value between the upper and lower limits of the ranges. Every smaller range between any stated value or stated range, and any other stated value or intermediate value within the stated range, is also encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference for the purpose of disclosing and describing the methods and/or materials associated with the documents. In case of conflict with any incorporated document, the present specification will control. As used herein, the terms "comprising," "including," "having," "containing," and the like are intended to be inclusive and mean an inclusion, but not limited to.
The experimental methods used in the present invention are conventional methods unless otherwise specified.
The materials, reagents and the like used in the present invention can be synthesized by a method of purchase or known method unless otherwise specified.
In the quantitative test of the invention, three repeated experiments are set, and the results are averaged.
Note that:
air for chromatography: the natural air is purified to remove water, greasy dirt and impurities in the air, and the air is stable and clean and is output by a pressure stabilizing device.
1. The invention provides a method for detecting the content of methanol in supercritical carbon dioxide, which comprises the following process steps:
(1) Removing impurity gas: and introducing chromatographic air into the sampling tank for 5-10 minutes to remove impurity gas.
(2) Sampling: collecting a sample (supercritical carbon dioxide containing methanol) by using a sampler, and conveying the sample into a sampling tank for storage through a pipeline; the sampling tanks need to be weighed before and after sampling, and the weighing tanks are respectively marked as m1 and m2. The weighing of the sampling tank is used for guaranteeing the constant sampling amount when the experiment is repeated, so that systematic errors caused by different sampling amounts are reduced.
(3) And (3) phase-change steady-state treatment: vacuumizing the sample processor until the pressure is-0.2 to-0.6 kpa; then heating the sample processor for 10-30 minutes at 110-140 ℃; conveying a sample in a sampling tank to a sample processor through a pipeline until the pressure is 0.2-0.6 kpa, stopping conveying the sample, and preserving heat at 110-140 ℃ for 5-10 min to obtain a stable gaseous sample;
(4) And conveying the sample in the sample processor to a gas chromatograph through a pipeline for detection.
The gas chromatograph has the working conditions that:
chromatographic column: a restek Stadilwax 32m x 0.53mm x 1 μm capillary chromatography column;
a detector: a hydrogen flame ionization detector;
sample inlet temperature: 180-220 ℃;
column box temperature: 110-140 ℃;
split ratio: 35-40:1;
split flow rate: 110-140 ml/min;
detecting the temperature: 230 ℃;
carrier gas: n (N) 2 The flow rate is 30ml/min;
hydrogen flow rate: 40ml/min;
air flow rate: 400ml/min;
sample injection amount: 20-40 mul.
2. The invention also discloses a detection device for realizing the detection processing method, which comprises a gas chromatograph 3 and a sample processor 2, wherein the sample processor 2 is used for carrying out phase-change steady-state processing on supercritical carbon dioxide and comprises a body 21, a suction filter 23 and a heater 24; the suction filter 23 is arranged on the body 21 through a pipeline, and the heater 24 is arranged outside the body 21 by adopting a heating jacket structure; the body 21 of the sample processor 2 is also provided with a thermometer 25 and a pressure gauge 22; the body 21 of the sample processor 2 is a high temperature and pressure resistant container; the discharge port of the sample processor 2 is connected with the feed port of the gas chromatograph 3.
The supercritical carbon dioxide is subjected to phase-change steady-state treatment by the sample processor 2 to obtain a stable gaseous sample, so that the situation that the supercritical carbon dioxide is directly gasified at normal temperature and normal pressure to cause the carbon dioxide to be gasified and refrigerated to form a solid to block the outlet of the sampler, and meanwhile, the situation that the solid carbon dioxide is gasified in the soft rubber bladder to cause excessive air pressure in the soft rubber bladder to swell and explode to hurt people and the sprayed solid causes frostbite of people is avoided, and the safety operation risk in the detection process is reduced. Meanwhile, the methanol in the sample processed by the sample processor can be gasified completely, so that the accuracy and reliability of the measurement result are improved.
In specific implementation, the device also comprises a sampler 1 with the function of impurity treatment; the sampler 1 comprises a sampling tank 11, a bypass pipeline 14 is arranged between a feed pipe 12 and a discharge pipe 13 of the sampling tank 11, valves are arranged on the feed pipe 12 and the discharge pipe 13, and a bypass valve 15 is further arranged on the bypass pipeline 14; the tail end of the discharging pipe 13 is provided with a three-way valve 16 which is respectively connected with an exhaust gas collection tank 17 and a feed inlet of the sample processor 2.
Thus, before sampling, the valve of the sampling tank 11 is closed, and the bypass valve 15 is opened, so that air in the pipeline can be discharged, and the gas collected by the sampling tank 11 is purer. Simultaneously, can avoid the impurity in the pipeline directly to discharge through the sampling jar 11, prevent that large granule impurity from getting into the sampling jar 11 and gathering and leading to can not discharge, influence the sampling volume and block up the gas outlet. And the tail end of the discharging pipe 13 of the sampling tank 11 is provided with an exhaust gas collecting tank 17, so that the collection of exhaust gas can be realized.
In particular, the sampling tank 11 is preferably a 316 pressure-resistant steel cylinder.
Working principle:
(1) Sampler processing: before the sampling tank is connected into the sampler, the sampling tank is connected with a compressed air device, valves at two ends of the sampling tank are opened, and chromatographic air is introduced into the sampling tank to remove impurity gas in the sampling tank;
(2) Sample introduction treatment: the sampling tank is connected into the sampler, valves at two ends of the sampling tank are closed, and a bypass valve is opened to remove impurity gas in a pipeline; closing the bypass valve, opening valves at two ends of the sampling tank, introducing samples into the sampling tank until the air in the sampling tank is discharged, closing the valve at the discharge port of the sampling tank, storing the samples in the sampling tank, and closing the valve at the feed port of the sampling tank;
(3) And (3) phase change treatment: connecting a discharge hole of a sampling tank with a feed hole of a sample processor, opening a suction filter to vacuumize the sample processor until the pressure is-0.2 to-0.6 kpa, and heating the sample processor for 10-30 minutes at 110-140 ℃; and conveying the sample in the sampling tank to a sample processor through a pipeline until the pressure is 0.2-0.6 kpa, stopping conveying the sample, and preserving heat at 110-140 ℃ for 5-10 min to obtain a stable gaseous sample.
(4) And (3) detection: and opening a discharge hole of the sample processor to enable the sample to flow into the gas chromatograph for sample content measurement.
3. Examples
Example 1
A method for detecting the content of methanol in supercritical carbon dioxide comprises the following process steps:
(1) Removing impurity gas: and selecting a 316 pressure-resistant steel cylinder, opening two-way valves at two ends of the steel cylinder, and introducing chromatographic air to replace the steel cylinder for 5 minutes to ensure that no residual impurity gas exists in the steel cylinder.
(2) Sampling: before sampling, a bypass valve is opened, a valve of a steel cylinder is closed, and a sample is introduced into a feed inlet of a sampler, so that the sample flows through the bypass valve to remove impurities remained in a pipeline; and 5 minutes later, closing the bypass valve, opening the steel cylinder valve, enabling the sample collected by the sampler to be conveyed into the steel cylinder through the pipeline, closing the valve of the steel cylinder discharge port after removing air in the steel cylinder, sampling, and closing the valve of the steel cylinder feed port after sampling is completed.
(3) Steady-state treatment:
(1) firstly, carrying out vacuumizing treatment on a sample processor through a vacuumizing filter, vacuumizing for 10 minutes until the surface of the vacuumizing filter is minus 0.2kpa, and closing a vacuumizing filter valve.
(2) The temperature of the heating sleeve sleeved outside the sample processor is regulated to 110 ℃ and the heating is carried out for 10 minutes.
(3) The cylinder was connected to a sample processor, the cylinder valve was opened, the sample was introduced into the sample processor, the pressure gauge was set at 0.2kpa for 2 minutes, the cylinder valve was closed, and the temperature was maintained at 110℃for 10 minutes to obtain a stable gaseous sample.
(4) And (3) content measurement: conveying a sample in the sample processor to a gas chromatograph through a pipeline for detection;
wherein, chromatograph operating condition is:
chromatographic column: a restek Stadilwax 32m x 0.53mm x 1 μm capillary chromatography column;
a detector: a hydrogen flame ionization detector;
sample inlet temperature: 180 ℃;
column box temperature: 110 ℃;
split ratio: 35:1;
split flow rate: 110ml/min;
detecting the temperature: 230 ℃;
carrier gas: n (N) 2 The flow rate is 30ml/min;
hydrogen flow rate: 40ml/min;
air flow rate: 400ml/min;
sample injection amount: 20 μl.
Example 2
A method for detecting the content of methanol in supercritical carbon dioxide comprises the following process steps:
(1) Removing impurity gas: and selecting a 316 pressure-resistant steel cylinder, opening two-way valves at two ends of the steel cylinder, and introducing chromatographic air to replace the steel cylinder for 5-10 minutes to ensure that no residual miscellaneous gas exists in the steel cylinder.
(2) Sampling: before sampling, a bypass valve is opened, a valve of a steel cylinder is closed, and a sample is introduced into a feed inlet of a sampler, so that the sample flows through the bypass valve to remove impurities remained in a pipeline; and after 10 minutes, the bypass valve is closed, the steel cylinder valve is opened, so that a sample collected by the sampler can be conveyed into the steel cylinder through a pipeline, after the air in the steel cylinder is discharged, the valve of the discharge hole of the steel cylinder is closed, sampling is carried out, and after the sampling is finished, the valve of the feed hole of the steel cylinder is closed.
(3) Steady-state treatment:
(1) firstly, carrying out vacuumizing treatment on a sample processor through a vacuumizing filter, vacuumizing for 20 minutes until the surface of the vacuumizing filter is minus 0.6kpa, and closing a vacuumizing filter valve.
(2) And (5) regulating the temperature to 140 ℃ by a heating sleeve sleeved outside the sample processor, and heating for 30 minutes.
(3) The cylinder was connected to a sample processor, the cylinder valve was opened, the sample was introduced into the sample processor, the 5 minute pressure gauge was set at 0.6kpa, the cylinder valve was closed, and the temperature was maintained at 140 ℃ for 5 minutes to obtain a stable gaseous sample.
(4) And (3) content measurement: conveying a sample in the sample processor to a gas chromatograph through a pipeline for detection;
wherein, chromatograph operating condition is:
chromatographic column: a restek Stadilwax 32m x 0.53mm x 1 μm capillary chromatography column;
a detector: a hydrogen flame ionization detector;
sample inlet temperature: 220 ℃;
column box temperature: 140 ℃;
split ratio: 40:1;
split flow rate: 140ml/min;
detecting the temperature: 230 ℃;
carrier gas: n (N) 2 The flow rate is 30ml/min;
hydrogen flow rate: 40ml/min;
air flow rate: 400ml/min;
sample injection amount: 40 μl.
Application examples
The test was repeated three times using the method described in example 1 for a 99:1 mass ratio of liquid carbon dioxide to methanol standard. The gas chromatograms of the obtained data are shown in FIGS. 2 to 4.
The three measured methanol contents were 1.0150%,1.0302%,0.9991%, respectively. The comparison of the prepared standard sample (preparation error of 0.08%), the error of less than 0.08% and the similar data of three groups proves that the detection by using the method and the device of the invention has accurate and reliable result.
Comparative example
The comparative example provides a method for detecting the content of methanol in supercritical carbon dioxide, which comprises the steps of gasifying a supercritical carbon dioxide sample containing methanol through a soft rubber bladder at normal temperature, directly introducing the gasified sample into a gas chromatograph for detecting the content of methanol, wherein the working condition of the chromatograph is the same as that of the embodiment 1.
The liquid carbon dioxide and methanol standard sample with the mass ratio of 99:1 are detected by adopting the method of the comparative example, and the detection is repeated three times. The gas chromatograms of the obtained data are shown in FIGS. 5-7.
The three measured methanol contents were 0.7418%,0.7037%,0.8923%, respectively. It can be seen that the methanol content measured by the method of the comparative example is low and the error is more than 0.08%, which indicates that the methanol component of the sample is changed and unstable in the treatment process, and the accuracy of the test result is far lower than that of the invention.
Finally, it should be noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the technical solution, and those skilled in the art should understand that modifications and equivalents may be made to the technical solution of the present invention without departing from the spirit and scope of the present invention, and all such modifications and equivalents are included in the scope of the claims.
Claims (5)
1. The method for detecting the methanol content in the supercritical carbon dioxide is characterized by comprising the following steps of:
(1) Sampling: collecting supercritical carbon dioxide containing methanol by using a sampler with impurity treatment function;
(2) And (3) phase-change steady-state treatment: carrying out phase-changing steady-state treatment on the sample collected in the step 1) by using a sample processor; firstly, vacuumizing a sample processor until the pressure is-0.2 to-0.6 kpa; then heating the sample processor for 10-30 minutes at 110-140 ℃; then, conveying the sample in the sampler to a sample processor until the pressure is 0.2-0.6 kpa, stopping conveying the sample, and preserving heat at 110-140 ℃ for 5-10 min;
(3) And (3) detection: and conveying the sample subjected to the phase-change steady-state treatment to a gas chromatograph through a pipeline for detection.
2. The method for detecting the methanol content in the supercritical carbon dioxide according to claim 1, wherein the sampler comprises a sampling tank, and wherein the air for chromatography is introduced into the sampling tank to remove the impurity gas before the sample is fed into the sampling tank.
3. The method for detecting the methanol content in the supercritical carbon dioxide according to claim 1, wherein the gas chromatograph operating conditions are:
chromatographic column: a restek Stadilwax 32m x 0.53mm x 1 μm capillary chromatography column;
a detector: a hydrogen flame ionization detector;
sample inlet temperature: 180-220 ℃;
column box temperature: 110-140 ℃;
split ratio: 35-40:1;
split flow rate: 110-140 ml/min;
detecting the temperature: 230 ℃;
carrier gas: n (N) 2 The flow rate is 30ml/min;
hydrogen flow rate: 40ml/min;
air flow rate: 400ml/min;
sample injection amount: 20-40 mul.
4. A device for detecting the methanol content in supercritical carbon dioxide, comprising a gas chromatograph, and further comprising a sample processor, wherein the sample processor is used for performing phase-change steady-state treatment on the supercritical carbon dioxide and comprises a body, a suction filter and a heater; the suction filter is arranged on the body through a pipeline, and the heater is arranged outside the body by adopting a heating sleeve structure; the body is also provided with a thermometer and a pressure gauge; the body is a high temperature and pressure resistant container; and the discharge port of the sample processor is connected with the feed port of the gas chromatograph.
5. The device for detecting the methanol content in the supercritical carbon dioxide according to claim 4, further comprising a sampler having a function of treating impurities; the sampler comprises a sampling tank, a bypass pipeline is arranged between a feeding pipe and a discharging pipe of the sampling tank, valves are arranged on the feeding pipe and the discharging pipe, and a bypass valve is further arranged on the bypass pipeline; the tail end of the discharging pipe is provided with a three-way valve which is respectively connected with the waste gas collection tank and the feed inlet of the sample processor.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311613592.XA CN117630217A (en) | 2023-11-29 | 2023-11-29 | Method and device for detecting methanol content in supercritical carbon dioxide |
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| CN202311613592.XA CN117630217A (en) | 2023-11-29 | 2023-11-29 | Method and device for detecting methanol content in supercritical carbon dioxide |
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| CN117630217A true CN117630217A (en) | 2024-03-01 |
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| CN202311613592.XA Pending CN117630217A (en) | 2023-11-29 | 2023-11-29 | Method and device for detecting methanol content in supercritical carbon dioxide |
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