CN117451961A - Seawater carbon dioxide measuring instrument calibration system and calibration method thereof - Google Patents
Seawater carbon dioxide measuring instrument calibration system and calibration method thereof Download PDFInfo
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- CN117451961A CN117451961A CN202311511433.9A CN202311511433A CN117451961A CN 117451961 A CN117451961 A CN 117451961A CN 202311511433 A CN202311511433 A CN 202311511433A CN 117451961 A CN117451961 A CN 117451961A
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- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 title claims abstract description 216
- 239000001569 carbon dioxide Substances 0.000 title claims abstract description 108
- 229910002092 carbon dioxide Inorganic materials 0.000 title claims abstract description 108
- 239000013535 sea water Substances 0.000 title claims abstract description 28
- 238000000034 method Methods 0.000 title claims abstract description 27
- 238000004164 analytical calibration Methods 0.000 title claims abstract description 6
- 239000007789 gas Substances 0.000 claims abstract description 119
- 238000011065 in-situ storage Methods 0.000 claims abstract description 34
- 238000012545 processing Methods 0.000 claims abstract description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 127
- 238000003860 storage Methods 0.000 claims description 42
- 238000007689 inspection Methods 0.000 claims description 30
- 239000000243 solution Substances 0.000 claims description 26
- 239000012528 membrane Substances 0.000 claims description 18
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 15
- 230000001105 regulatory effect Effects 0.000 claims description 14
- 238000001035 drying Methods 0.000 claims description 9
- 238000007605 air drying Methods 0.000 claims description 8
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 5
- 239000012466 permeate Substances 0.000 claims description 5
- 230000009471 action Effects 0.000 claims description 4
- 238000002347 injection Methods 0.000 claims description 2
- 239000007924 injection Substances 0.000 claims description 2
- 238000001514 detection method Methods 0.000 abstract description 4
- 238000010586 diagram Methods 0.000 description 5
- 238000005259 measurement Methods 0.000 description 5
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 230000008859 change Effects 0.000 description 3
- 239000008367 deionised water Substances 0.000 description 3
- 229910021641 deionized water Inorganic materials 0.000 description 3
- 238000000605 extraction Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 229910000029 sodium carbonate Inorganic materials 0.000 description 2
- 235000014653 Carica parviflora Nutrition 0.000 description 1
- 241000243321 Cnidaria Species 0.000 description 1
- UIIMBOGNXHQVGW-DEQYMQKBSA-M Sodium bicarbonate-14C Chemical compound [Na+].O[14C]([O-])=O UIIMBOGNXHQVGW-DEQYMQKBSA-M 0.000 description 1
- 230000001174 ascending effect Effects 0.000 description 1
- 238000009530 blood pressure measurement Methods 0.000 description 1
- 239000000872 buffer Substances 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000020477 pH reduction Effects 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 1
- 235000017557 sodium bicarbonate Nutrition 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/18—Water
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- Analytical Chemistry (AREA)
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- General Health & Medical Sciences (AREA)
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Abstract
The invention belongs to the field of carbon dioxide detectors, in particular to a calibration method of a seawater carbon dioxide measuring instrument calibration system, which comprises the following steps: s1, inputting a plurality of standard gases with different partial pressure gradients of different carbon dioxide, and checking and calibrating a standard detector for a plurality of times; s2, after calibration of the standard detector is completed, calibrating the balancer assembly; s3, starting calibration work, opening a waterway, observing and comparing data of the standard detector and the underwater in-situ carbon dioxide measuring instrument in real time to obtain compared data, and completing calibration of the underwater in-situ carbon dioxide measuring instrument; s4, recording and processing the compared data to obtain the calibration coefficient of the underwater in-situ carbon dioxide measuring instrument. The invention ensures that each component part in the system is accurate before calibration, can furthest reduce the interference of external environment, then opens a waterway, observes and compares the data of the standard detector and the underwater in-situ carbon dioxide measuring instrument in real time, and realizes high-precision detection and calibration.
Description
Technical Field
The invention belongs to the field of carbon dioxide detectors, and particularly relates to a calibration system and a calibration method of a seawater carbon dioxide measuring instrument.
Background
Accurate determination of the partial pressure of carbon dioxide in seawater is critical to reveal the role of the ocean in global climate change. In general, the ways to obtain the partial pressure of carbon dioxide in seawater include two ways: continuous observation of the navigation carbon dioxide and long-term observation of the fixed-point in-situ carbon dioxide sensor. The seawater carbon dioxide sensor based on the permeable membrane technology can acquire a large amount of in-situ data, and is widely applied to global climate change in offshore, oceanic, polar regions and other sea areas and ocean acidification research in coral reef and other sensitive areas. In the long-term use process of the carbon dioxide sensor in the field, the carbon dioxide sensor is inevitably subject to data drift due to the influences of biological contamination, loss of components and parts of the carbon dioxide sensor, and the like, so that the sensor calibration needs to be performed regularly.
Currently, in the prior art, the same carbon dioxide partial pressure value under the same environment is used for calibrating the underwater in-situ carbon dioxide measuring instrument, and the corresponding same carbon dioxide partial pressure value is used, so that the calibration accuracy is affected by the current environment, and meanwhile, the solubility of carbon dioxide in water is low, the dissolution rate is slow, so that the change of the carbon dioxide concentration in a large-volume water body becomes very difficult, and an effective calibration method for quickly changing the carbon dioxide concentration is lacked; secondly, the existing calibration methods all adopt direct measurement by a standard detector, and no calibration method capable of determining the relation between the standard value and the measured value of the partial pressure value of carbon dioxide is available, so that the measurement result of the same partial pressure value of carbon dioxide in the same environment can be obtained, and a carbon dioxide detection device is also providedSome devices directly use a spray-type water-gas balancer to mix CO in a water sample 2 After extraction, the carbon dioxide measuring instrument is introduced into a standard detector for detection, and the deviation exists in the extraction process, and the extraction result is unique, so that the error occurs in the subsequent calibration process of the carbon dioxide measuring instrument.
Therefore, the calibration system and the calibration method of the seawater carbon dioxide measuring instrument are established, and timely and accurate calibration service is provided for the seawater carbon dioxide sensor in the use process of the seawater carbon dioxide sensor, so that the seawater carbon dioxide measuring instrument is beneficial to better playing an important role of the seawater carbon dioxide sensor in marine scientific research activities.
Disclosure of Invention
The invention aims to provide a seawater carbon dioxide measuring instrument calibration system and a calibration method thereof, which are used for solving the problems that in the prior art, the calibration of a carbon dioxide measuring instrument calibration device is inaccurate and no corresponding accurate calibration mode exists.
The technical scheme adopted by the invention for achieving the purpose is as follows: a calibration method of a seawater capnometer calibration system, comprising the steps of:
s1: inputting a plurality of standard gases with different partial pressure gradients of different carbon dioxide, and checking and calibrating the standard detector for a plurality of times;
s2: after calibration of the standard detector is completed, calibrating the balancer assembly;
s3: starting the calibration work, opening a waterway, observing and comparing the data of the standard detector and the data of the underwater in-situ carbon dioxide measuring instrument in real time to obtain the compared data, and completing the calibration of the underwater in-situ carbon dioxide measuring instrument;
s4: recording and processing the compared data to obtain the calibration coefficient of the underwater in-situ carbon dioxide measuring instrument.
The multiple times of checking and calibrating the standard detector comprises the following steps:
s1.1: starting a standard detector, preheating for 30min, and stopping the waterway circulation assembly at the moment;
s1.2: the two-way four-way valve of the balancer assembly is adjusted to enable the standard gas path to be communicated, namely, the three-way valve, the two-way four-way valve, the barometer, the cross four-way valve and the gas drying pipe are sequentially connected in series to form a communicated gas flow path, and the gas flow path is connected to the standard detector after the gas flow path is formed;
s1.3: through the multi-way valve of the standard gas assembly, a plurality of standard gases with different gradients are input to the standard detector, the standard detector is calibrated, and after the calibration is finished, the gas flowing out of the standard detector is conveyed to the cross four-way valve, flows to the three-way reversing valve and is discharged to the atmosphere through the exhaust pipeline.
The calibrating of the balancer assembly includes the steps of:
s2.1: the waterway circulation route is still in a closed state, and the air passage inspection device is arranged at the balance membrane in the balancer assembly;
s2.2: the two-way four-way valve is adjusted to enable the balance air channel to be communicated, namely the air chamber, the condenser, the air pump, the two-way four-way valve, the barometer, the cross four-way valve and the air drying pipe are sequentially connected in series to form a communicated air flow channel, and then the standard detector is connected;
s2.3: changing a three-way valve in a standard gas path to enable gas from the three-way valve to be introduced into a balancer gas path inspection device;
s2.4: standard gases with different gradients are input, pass through a multi-way valve, go to a three-way valve, then enter a balancer gas path inspection device, pass through a balancing film, flow into a balancing gas path, and then enter a standard detector;
s2.5: and comparing the output value of the standard detector with the standard gas, so as to check whether the balance system works normally.
The step S3 specifically includes:
s3.1: closing the multi-way valve to cut off the gas path of the standard gas, disassembling the gas path inspection device on the balance film, and installing the water path overflow device at the original position of the gas path inspection device of the balance film in the balancer assembly;
s3.2: the waterway circulation assembly is opened, water in the water storage container is sequentially conveyed to the waterway flow-through device through the waterway diverter and the flow controller by the output pipeline, and the water flows back into the water storage container under the action of the balance film;
carbon dioxide in the water permeates the balance membrane and enters the air chamber, and a balance air path is opened, so that the carbon dioxide in the water storage container enters the standard detector;
s3.3: observing and comparing the data of the standard detector and the underwater in-situ carbon dioxide measuring instrument in real time;
s3.4: injecting the acid-base regulating solution into the water storage container for multiple times to enable the partial pressure of carbon dioxide in water to be in different gradients, measuring for multiple times, and recording data;
the acid-base regulating solution is any one of a dilute hydrochloric acid solution with the concentration of 0.5mol/L or a sodium hydroxide solution with the concentration of 0.5 mol/L;
the solution is injected and regulated to separate at least 5 different gradients of carbon dioxide partial pressures in water, wherein the partial pressures comprise zero gradients, and the difference of the carbon dioxide partial pressures between every two adjacent gradients is not less than 200ppm.
The calibration coefficient of the underwater in-situ carbon dioxide measuring instrument is obtained specifically as follows:
obtaining the relation between the standard value and the measured value through polynomial fitting, and R 2 > 0.999, i.e.:
y＝Ax 3 +Bx 2 +Cx+D
wherein y is a standard value, x is a measured value, and A, B, C, D are polynomial fitting coefficients respectively.
A seawater capnometer calibration system, comprising: the device comprises a water storage container, a temperature controller, a waterway circulation assembly, a balancer assembly, a standard detector and a gas marking assembly;
an underwater carbon dioxide measuring instrument is arranged in the water storage container; the circulating loop of the temperature controller passes through the inside of the water storage container so as to keep the temperature in the water storage container;
one end of the waterway circulation assembly is connected with the water outlet end of the water storage container, the other end of the waterway circulation assembly is connected with the balancer assembly, and the balancer assembly is connected with the water return end of the water storage container through a water pipe;
the air marking assembly comprises: a multi-way valve, a gas flow controller, and a three-way valve;
multiple groups of standard gases are connected in parallel into corresponding valves of the multi-way valves, and the multi-way valves are connected with the three-way valves through gas paths;
the gas flow controller is arranged on a gas path between the multi-way valve and the three-way valve to control the gas flow to enter the three-way valve;
the other two output ends of the three-way valve are respectively connected with the standard detector and the balancer component through pipelines.
The balancer assembly comprises a balancer, a balancing film, an air chamber, a waterway overcurrent device, an air passage inspection device and an air passage assembly which are arranged on the balancer;
the water path flow device or the air path inspection device is arranged on the balance film and positioned outside the balancer, the water path flow device is connected with the water path circulation assembly, and the air path inspection device is connected with the three-way valve; the air chamber is connected with the standard detector through the air path component;
the gas circuit subassembly includes: the device comprises a condenser, an air pump, a two-way four-way valve, a barometer, a cross four-way valve and a gas drying pipe connected with a standard detector;
the input end of the condenser is connected with the air chamber, the output end of the condenser is connected with the first port of the two-way four-way valve through the air pump, so that air in the air chamber is pumped out through the air pump and is conveyed to the two-way four-way valve through the condenser;
the second port of the two-way four-way valve is used for connecting the gas pumped by the air pump with the standard detector through the barometer, the cross four-way valve and the gas drying pipe in sequence;
the third port of the two-way four-way valve is used as an input end to be connected with a three-way valve of the air marking assembly;
the fourth port of the two-way four-way valve is used as an output end to be connected with the input end of the three-way valve and is discharged to the atmosphere through an exhaust pipeline on the output end of the three-way valve.
The air pump, the two-way four-way valve, the barometer, the cross four-way valve and the air drying pipe are fixed in the mounting chamber, and the condenser is fixedly arranged outside the balancer;
the standard detector extends out of a pipeline and is connected with a cross four-way valve of the gas circuit assembly, one output end of the cross four-way valve is connected with a three-way reversing valve through a pipeline, and two outlets of the three-way reversing valve are respectively connected into the balance membrane cavity and the exhaust pipeline.
The water storage container is internally provided with configured water and is communicated with an acid-base injection device so as to prepare the water in the water storage container into an acid-base regulating solution;
the regulating solution is any one of 0.5mol/L dilute hydrochloric acid solution or 0.5mol/L sodium hydroxide solution;
the solution is injected and regulated to separate at least 5 different gradients of carbon dioxide partial pressures in water, wherein the partial pressures comprise zero gradients, and the difference of the carbon dioxide partial pressures between every two adjacent gradients is not less than 200ppm.
The invention has the following beneficial effects and advantages:
1. before the underwater in-situ carbon dioxide measuring instrument is calibrated, the standard detector in the system is calibrated by using different gradients of partial pressure values of carbon dioxide, the balancer component is calibrated by using the standard detector after inspection, each component and part in the whole system are ensured to be accurate before calibration, the interference of external environment can be reduced to the maximum extent, then a waterway is started, and the data of the standard detector and the underwater in-situ carbon dioxide measuring instrument are observed and compared in real time, so that high-precision detection and calibration are realized.
2. According to the invention, by means of connecting multiple groups of standard gases with the multi-way valve in parallel and then connecting the multi-way valve with the three-way valve, the standard detector is calibrated multiple times by utilizing the multiple groups of standard gases which contain different partial pressure gradients of carbon dioxide, and the balancer component is calibrated by the standard detector after inspection, so that each component and part in the whole system are ensured to be accurate before calibration. And the gas path component is designed in the balancer component, so that carbon dioxide gas which can permeate through a waterway well is dried, and then the carbon dioxide gas is introduced into the standard detector, and the calibration system is accurate.
Drawings
FIG. 1 is a flow chart of a calibration method of the structure of the present invention;
FIG. 2 is a diagram of the water and gas paths of the calibration system when the calibration standard detects gas;
FIG. 3 is a diagram of the water and air paths of the calibration system when calibrating the balancer assembly;
FIG. 4 is a diagram of the waterway and gas circuit flow of the complete system when calibrating the underwater in-situ capnometer;
FIG. 5 is a linear diagram of the random underwater in-situ capnometer of the present embodiment;
wherein 1 is the casing, 2 is the balanced membrane chamber, and 3 is the water route overflow arrangement.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1, a flow chart of a calibration method of the structure of the present invention is shown, and the calibration method of the calibration system of the seawater carbon dioxide measuring instrument of the present invention comprises the following steps:
s1, preparing work;
s2, inputting standard gases with different partial pressure gradients of carbon dioxide, and checking and calibrating the standard detector for a plurality of times;
s3, calibrating the balancer assembly;
s4, starting calibration work, opening a waterway, and observing and comparing data of the standard detector and the underwater in-situ carbon dioxide measuring instrument in real time;
s5, recording and processing data, and obtaining a calibration coefficient.
The preparation work in step S1 is specifically as follows:
s1.1 preparation
S1.1.1, determining a specific use environment of the underwater in-situ carbon dioxide measuring instrument, wherein the specific use environment comprises a carbon dioxide partial pressure measuring range and a use environment temperature range, so as to determine a calibration range and a calibration environment temperature of the underwater in-situ carbon dioxide measuring instrument;
the calibration range of the underwater in-situ carbon dioxide measuring instrument needs to cover the partial pressure measurement range of the carbon dioxide in the use environment; setting the calibration environment temperature of the underwater in-situ carbon dioxide measuring instrument as the median of the using environment temperature range;
s1.1.2 a sufficient quantity of deionized water is prepared, a high pressure standard gas of at least 5 gradients is prepared, and a buffer reagent is prepared: sodium carbonate and sodium bicarbonate, ready to adjust solution
S1.2 checking:
checking that all components of the system are connected well and the air tightness of the connection is good; check if each partial assembly is working properly.
S1.3 adjusting the calibration Environment
S1.3.1 the laboratory air conditioner is set to calibrate the ambient temperature and the laboratory ventilator is turned on;
s1.3.2 the bucket is filled with deionized water, 28g of sodium bicarbonate and 0.5g of sodium carbonate are used for being put into the deionized water, and the seawater environment is simulated;
s1.3.3 closing each split valve of the waterway circulation system, only keeping the main circulation pipeline, and opening the water suction pump to keep the circulating flow of the experimental water for calibration;
s1.3.4 opening a temperature controller, setting a target temperature to be a calibration environment temperature, starting all underwater in-situ carbon dioxide measuring instruments to be calibrated, and keeping the state for one night;
s1.3.5 the high-pressure gas first-stage pressure reducing valve is opened, the gas pressure is adjusted to be 2Bar, the second-stage pressure reducing valve is opened, and the gas pressure is adjusted to be 1Bar.
As shown in fig. 2, the calibration method of the standard detector in step S2 specifically includes the following steps:
s2.1, starting a standard detector, preheating for 30min, and stopping the work of the waterway circulation line at the moment;
s2.2, adjusting a two-way four-way valve in the balancer to enable the standard gas path to be communicated, namely, sequentially connecting the three-way valve, the two-way four-way valve, the barometer, the cross four-way valve and the gas drying pipe in series to form a communicated gas flow path, and then connecting the standard detector;
s2.3, inputting at least 5 standard gases with different gradients to the standard detector through the multi-way valve, calibrating the standard detector, and after the calibration is finished, returning the gas coming out of the standard detector to the cross four-way valve, then flowing to the three-way reversing valve, and finally discharging along with an exhaust pipeline.
At least 5 gradients of standard air, standard air must be used instead of standard carbon dioxide gas with pure nitrogen as carrier gas. The standard gases with 5 different gradients, namely the partial pressure values of carbon dioxide in the standard gases are different, the lowest point of the concentration range of the standard air must be 0 point (namely the standard air without carbon dioxide), and the maximum point of the concentration range of the standard air must be capable of covering the maximum value of the target calibration range, and the closer the maximum point is, the better the maximum point is. Standard air is used as a reference, the standard detector can be calibrated, and the balancer can be checked.
Before each standard gas path is connected with the multi-way valve, a two-stage pressure reducing valve is connected, so that high-pressure standard air in the standard gas path can be subjected to two-stage pressure reduction, and the gas pressure is controlled to be slightly higher than 1Bar. In the working process, the on-off of the gas circuit can be controlled by switching the secondary pressure reducing valve.
As shown in fig. 3, the specific method for calibrating the balancer assembly in step S3:
s3.1, the waterway circulation route is still in a closed state, and the air passage inspection device is arranged at a balancing film in the balancer assembly;
s3.2, adjusting the two-way four-way valve to enable the balance air channel to be communicated, namely, the air chamber, the condenser, the air pump, the two-way four-way valve, the barometer, the cross four-way valve and the air drying pipe to be sequentially connected in series to form a communicated air flow channel, and then connecting the standard detector;
s3.3, changing a three-way valve in the standard gas path, and leading the gas coming out of the three-way valve to a balancer gas path inspection device;
s3.4, standard gases with different gradients are input, pass through a multi-way valve, go to a three-way valve, then enter a balancer gas path inspection device, pass through a balancing film, flow into a balancing gas path, and then enter a standard detector;
s3.5, comparing the output value of the standard detector with the standard gas, so as to check whether the balance system works normally.
As shown in fig. 4, the specific method for calibrating the underwater in-situ capnometer in step S4 is as follows:
s4.1, closing a standard gas path, removing the gas path inspection device from the balance film, and then installing the water path overflow device at the balance film in the balancer assembly;
s4.2, opening a waterway, leading water in the water storage container to a water channel overflow device through a waterway assembly, and enabling the water to flow back to the water storage container under the action of a balance membrane; carbon dioxide in the water permeates the balance membrane and enters the air chamber, and a balance air path is opened, so that the carbon dioxide in the water storage container enters the standard detector;
s4.3, real-time observation and comparison of data of a standard detector and the underwater in-situ carbon dioxide measuring instrument;
s4.4, injecting the regulating solution into the water storage container for multiple times to enable the partial pressure of carbon dioxide in water to be different in gradient, measuring for multiple times, and recording data.
The regulating solution is 0.5mol/L dilute hydrochloric acid solution or 0.5mol/L sodium hydroxide solution;
and the solution is injected and regulated, so that at least 5 carbon dioxide partial pressures with different gradients are separated from water, the carbon dioxide partial pressures comprise zero gradients, the zero does not need to be allocated with experimental water, and an underwater in-situ carbon dioxide measuring instrument can be arranged to close an external gas path and perform internal zeroing measurement. The partial pressure of carbon dioxide between every two adjacent gradients differs by not less than 200ppm.
Wherein the measurement of 5 gradients may not be performed in ascending or descending order, with at least one gradient being the intersection. Such as: the planning gradient is: 0. 200, 400, 600, 800, the actual measurement order may be 0, 200, 600, 400, 800.
When the underwater in-situ carbon dioxide measuring instrument is calibrated, 5 standard gases with different gradients do not pass through the multi-way valve, namely the standard gas circuit does not work.
Step S5, data are processed and calibration coefficients are obtained:
obtaining the relation between the standard value and the measured value through polynomial fittingAnd R is 2 > 0.999, i.e.:
y＝Ax 3 +Bx 2 +Cx+D
wherein y is a standard value, x is a measured value, and A, B, C, D are polynomial fitting coefficients respectively.
In combination with the calibration method of the present invention, as shown in fig. 4, the present invention proposes a calibration system for a seawater carbon dioxide measuring instrument, comprising: the device comprises a water storage container, a temperature controller for controlling the water storage container at constant temperature, a waterway circulation assembly, a balancer assembly, a standard detector and a standard gas assembly, wherein an underwater carbon dioxide measuring instrument is arranged in the water storage container; the water storage container is used for simulating the seawater water environment, and the carbon dioxide measuring instrument to be calibrated is arranged in the water storage container;
one end of the waterway circulation assembly is connected with the water outlet end of the water storage container, the other end of the waterway circulation assembly is connected with the balancer assembly, and the balancer assembly is connected with the water return end of the water storage container through a water pipe.
Waterway circulation assembly, comprising: the water path diverter, the flow controller, the input pipeline and the output pipeline;
the input pipeline and the output pipeline are respectively connected to the input end and the output end of the water storage container, form a circulating pipeline, and are divided at intervals through the waterway divider; the waterway diverter is connected with the waterway flow device through the flow controller.
The standard gas assembly comprises a plurality of groups of standard gases, a multi-way valve and a three-way valve, wherein the plurality of groups of standard gases are connected with the multi-way valve in a parallel mode, in the embodiment, the standard gases are divided into five groups, the air pressure of each group of standard gases is 1Bar, the five groups of different standard gases are different in partial pressure value of carbon dioxide in the standard gases, the multi-way valve is provided with 5 input ports and is connected with the three-way valve through an air circuit, the air circuit is provided with a gas flow controller, and the other two ends of the three-way valve are respectively connected with the standard detector and the balancer assembly through pipelines;
a balancer assembly comprising: the balance device comprises a balance device, a balance film positioned in the balance device, an air chamber positioned behind the balance film, a waterway flow device 2, an air passage inspection device and an air passage assembly,
the water passage flow device 2 is manufactured by the following manufacturers: german 4H-JENA ENGINEERING; model: CONTROS HydroC TM CO 2 The water passage flow device and the air passage inspection device of the FT are selected from the following manufacturers: LI-COR in the United states; model: LI-7815;
the water path flow device 2 or the air path inspection device is arranged outside the balance film, the water path flow device 2 or the air path inspection device is arranged at the same position in a replacement mode according to calibration of different systems, the air path flow device 2 is connected with the water path circulation assembly, the air path inspection device is connected with the three-way valve, and the air chamber is connected with the standard detector through the air path assembly.
In this embodiment, the water path flow device 2 includes 1 water inlet pipe and 2 water outlet pipes;
the output end of the water storage container is connected with the water inlet pipe through the waterway diverter and the flow controller in sequence; one of the water outlet pipes of the waterway overflow device is connected with the condenser, and the other water outlet pipe is connected with the input end of the water storage container through the input pipeline of the waterway circulation assembly.
The air circuit component comprises a condenser, an air pump, a two-way four-way valve, an air pressure gauge, a cross four-way valve and an air drying pipe connected with the standard detector,
one end of the condenser is connected with the air chamber, the other end of the condenser is connected with the air pump, air in the air chamber is pumped out through the air pump, passes through the condenser and then is communicated with one port of the two-way four-way valve, a second port of the two-way four-way valve is sequentially connected with the barometer, the cross four-way valve and the air drying pipe in series, and a third port of the two-way four-way valve is connected into an exhaust pipeline through a fourth port of the two-way four-way valve and the three-way valve.
The standard detector extends out of a pipeline and is connected with a cross four-way valve, the cross four-way valve is connected with a three-way reversing valve through a pipeline, and two outlets of the three-way reversing valve are respectively connected with a balance film and an exhaust pipeline. And the exhaust pipeline is also provided with a three-way valve which is also connected with the two-way four-way valve.
The balancer includes casing 1, and the front end of casing 1 is equipped with circular shape balanced membrane chamber 2, be equipped with the installation room in the casing 1, the vertical fixation in balanced membrane chamber 2 balanced membrane is in through the bolt fastening on the balanced membrane chamber 2, and air pump, double-circuit cross valve, barometer, cross valve, gas drying pipe are all fixed in the installation room, and the condenser is located the balancer outside.
The water storage container is preferably a bucket, and is wrapped by the heat preservation layer, so that the exchange with the outside temperature is reduced. The inside is provided with the configured experimental water for calibration, and the outside is connected with the waterway system.
The temperature controller flows a temperature control waterway in the temperature controller through the inside of the water bucket, so that the temperature controller can accurately and stably control the temperature of experimental water in the water bucket.
The waterway circulation assembly includes:
the waterway is divided, a pipeline made of PVC or PPR materials and a valve are adopted to make a multi-branch design, so that water flow in the pipeline flows or is divided according to a preset direction;
the water pump is connected in the main pipeline and pumps the experimental water in the water bucket into the waterway system to generate circulating power;
the balance pipeline adopts a hose without carbon dioxide permeation material, and one path of split water is connected into the balancer water path flow-through device from the split system of the waterway circulation system, and the water is circularly introduced into the waterway circulation system;
the water flow controller is arranged in the inlet pipeline of the balance pipeline and can control experimental water to be stably introduced into the balancer water path flow device.
Example 1:
referring to fig. 4, the standard detector is calibrated by passing five groups of different carbon dioxide partial pressure gradient standard gases through the multi-way valve, then through the three-way valve, and the gases enter the two-way four-way valve in the balancer assembly, the second end and the third end of the two-way four-way valve are connected, then enter the barometer, then enter the cross four-way valve and the gas drying pipe, and finally enter the standard detector. After the step is finished, calibrating the balancer component, when calibrating the standard detector and the balancer component, the water flow is in a closed state, the gas circuit inspection device is fixed at the front end of the balancing film to replace the position of the water circuit flow-through device 3, five groups of different carbon dioxide partial pressure gradient standard gases pass through the multi-way valve and then enter the balancer inspection device through the three-way valve, the gases sequentially enter the condenser and the air pump through the balancing film, the first end and the second end of the two-way four-way valve are communicated, and then enter the barometer, the cross four-way valve and the air drying pipe, and finally enter the standard detector to calibrate the balancer component.
And after the calibration of the standard detector and the balancer assembly is finished, calibrating the underwater carbon dioxide measuring instrument. Removing the air passage inspection device from the balance membrane, and then installing the water passage overflow device 3 on a balance membrane cavity in the balancer assembly; opening a waterway, leading water in the water storage container to a water channel flow device 3 through a waterway assembly, and enabling water to flow back into the water storage container under the action of a balance membrane at the moment; carbon dioxide in the water permeates the balance membrane, enters the air chamber, opens the balance air path, enables the carbon dioxide in the water storage container to enter the standard detector, and records data.
With the calibration system, an underwater carbon dioxide in-situ measuring instrument is adopted, 5 different gradients are adopted for calibration, and the calibration data are shown in table 1, and the unit ppm is as follows:
TABLE 1
| Sequence number | Partial pressure value of underwater in-situ carbon dioxide measuring instrument | Partial pressure value of standard detector |
| 1 | 0.11 | 0 |
| 2 | 221.32 | 201.35 |
| 3 | 658.26 | 599.63 |
| 4 | 441.69 | 403.25 |
| 5 | 892.93 | 810.79 |
As shown in fig. 5, a linear diagram of the random underwater in-situ carbon dioxide measuring instrument according to this embodiment is obtained, and a fitting formula in this embodiment is as follows: y= -2E-08x 3 +2E-05x 2 +0.9084x-0.1574, where R 2 ＝1；
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the invention.
Claims (9)
1. A method for calibrating a seawater capnometer calibration system, comprising the steps of:
s1: inputting a plurality of standard gases with different partial pressure gradients of different carbon dioxide, and checking and calibrating the standard detector for a plurality of times;
s2: after calibration of the standard detector is completed, calibrating the balancer assembly;
s3: starting the calibration work, opening a waterway, observing and comparing the data of the standard detector and the data of the underwater in-situ carbon dioxide measuring instrument in real time to obtain the compared data, and completing the calibration of the underwater in-situ carbon dioxide measuring instrument;
s4: recording and processing the compared data to obtain the calibration coefficient of the underwater in-situ carbon dioxide measuring instrument.
2. The method for calibrating a calibration system for a seawater capnometer of claim 1, wherein said plurality of calibration tests for a standard detector comprises the steps of:
s1.1: starting a standard detector, preheating for 30min, and stopping the waterway circulation assembly at the moment;
s1.2: the two-way four-way valve of the balancer assembly is adjusted to enable the standard gas path to be communicated, namely, the three-way valve, the two-way four-way valve, the barometer, the cross four-way valve and the gas drying pipe are sequentially connected in series to form a communicated gas flow path, and the gas flow path is connected to the standard detector after the gas flow path is formed;
s1.3: through the multi-way valve of the standard gas assembly, a plurality of standard gases with different gradients are input to the standard detector, the standard detector is calibrated, and after the calibration is finished, the gas flowing out of the standard detector is conveyed to the cross four-way valve, flows to the three-way reversing valve and is discharged to the atmosphere through the exhaust pipeline.
3. A method of calibrating a seawater capnometer calibration system as set forth in claim 1, wherein said calibrating the balancer assembly comprises the steps of:
s2.1: the waterway circulation route is still in a closed state, and the air passage inspection device is arranged at the balance membrane in the balancer assembly;
s2.2: the two-way four-way valve is adjusted to enable the balance air channel to be communicated, namely the air chamber, the condenser, the air pump, the two-way four-way valve, the barometer, the cross four-way valve and the air drying pipe are sequentially connected in series to form a communicated air flow channel, and then the standard detector is connected;
s2.3: changing a three-way valve in a standard gas path to enable gas from the three-way valve to be introduced into a balancer gas path inspection device;
s2.4: standard gases with different gradients are input, pass through a multi-way valve, go to a three-way valve, then enter a balancer gas path inspection device, pass through a balancing film, flow into a balancing gas path, and then enter a standard detector;
s2.5: and comparing the output value of the standard detector with the standard gas, so as to check whether the balance system works normally.
4. The calibration method of the calibration system of the seawater carbon dioxide measuring instrument according to claim 1, wherein the step S3 specifically comprises:
s3.1: closing the multi-way valve to cut off the gas path of the standard gas, disassembling the gas path inspection device on the balance film, and installing the water path overflow device at the original position of the gas path inspection device of the balance film in the balancer assembly;
s3.2: the waterway circulation assembly is opened, water in the water storage container is sequentially conveyed to the waterway flow-through device through the waterway diverter and the flow controller by the output pipeline, and the water flows back into the water storage container under the action of the balance film;
carbon dioxide in the water permeates the balance membrane and enters the air chamber, and a balance air path is opened, so that the carbon dioxide in the water storage container enters the standard detector;
s3.3: observing and comparing the data of the standard detector and the underwater in-situ carbon dioxide measuring instrument in real time;
s3.4: and (3) injecting the acid-base regulating solution into the water storage container for multiple times to enable the partial pressure of carbon dioxide in water to be in different gradients, measuring for multiple times, and recording data.
5. The method for calibrating a seawater capnometer calibration system according to claim 4, wherein the acid-base adjusting solution is either a dilute hydrochloric acid solution of 0.5mol/L or a sodium hydroxide solution of 0.5 mol/L;
the solution is injected and regulated to separate at least 5 different gradients of carbon dioxide partial pressures in water, wherein the partial pressures comprise zero gradients, and the difference of the carbon dioxide partial pressures between every two adjacent gradients is not less than 200ppm.
6. The method for calibrating a seawater capnometer calibration system of claim 1, wherein the obtaining calibration coefficients of the underwater in-situ capnometer is specifically:
obtaining the relation between the standard value and the measured value through polynomial fitting, and R 2 > 0.999, i.e.:
y＝Ax 3 +Bx 2 +Cx+D
wherein y is a standard value, x is a measured value, and A, B, C, D are polynomial fitting coefficients respectively.
7. A seawater capnometer calibration system, comprising: the device comprises a water storage container, a temperature controller, a waterway circulation assembly, a balancer assembly, a standard detector and a gas marking assembly;
an underwater carbon dioxide measuring instrument is arranged in the water storage container; the circulating loop of the temperature controller passes through the inside of the water storage container so as to keep the temperature in the water storage container;
one end of the waterway circulation assembly is connected with the water outlet end of the water storage container, the other end of the waterway circulation assembly is connected with the balancer assembly, and the balancer assembly is connected with the water return end of the water storage container through a water pipe;
the air marking assembly comprises: a multi-way valve, a gas flow controller, and a three-way valve;
multiple groups of standard gases are connected in parallel into corresponding valves of the multi-way valves, and the multi-way valves are connected with the three-way valves through gas paths;
the gas flow controller is arranged on a gas path between the multi-way valve and the three-way valve to control the gas flow to enter the three-way valve;
the other two output ends of the three-way valve are respectively connected with the standard detector and the balancer component through pipelines.
8. The seawater carbon dioxide measuring instrument calibration system of claim 7, wherein the balancer assembly comprises a balancer, and a balancing film, an air chamber, a water passage flow device, an air passage inspection device and an air passage assembly which are arranged on the balancer;
the water path flow device or the air path inspection device is arranged on the balance film and positioned outside the balancer, the water path flow device is connected with the water path circulation assembly, and the air path inspection device is connected with the three-way valve; the air chamber is connected with the standard detector through the air path component;
the gas circuit subassembly includes: the device comprises a condenser, an air pump, a two-way four-way valve, a barometer, a cross four-way valve and a gas drying pipe connected with a standard detector;
the input end of the condenser is connected with the air chamber, the output end of the condenser is connected with the first port of the two-way four-way valve through the air pump, so that air in the air chamber is pumped out through the air pump and is conveyed to the two-way four-way valve through the condenser;
the second port of the two-way four-way valve is used for connecting the gas pumped by the air pump with the standard detector through the barometer, the cross four-way valve and the gas drying pipe in sequence;
the third port of the two-way four-way valve is used as an input end to be connected with a three-way valve of the air marking assembly;
the fourth port of the two-way four-way valve is used as an output end to be connected with the input end of the three-way valve and is discharged to the atmosphere through an exhaust pipeline on the output end of the three-way valve.
The air pump, the two-way four-way valve, the barometer, the cross four-way valve and the air drying pipe are fixed in the mounting chamber, and the condenser is fixedly arranged outside the balancer;
the standard detector extends out of a pipeline and is connected with a cross four-way valve of the gas circuit assembly, one output end of the cross four-way valve is connected with a three-way reversing valve through a pipeline, and two outlets of the three-way reversing valve are respectively connected into the balance membrane cavity and the exhaust pipeline.
9. The calibration system of the seawater carbon dioxide measuring instrument according to claim 7, wherein the water storage container is internally provided with configured water and is communicated with an acid-base injection device so as to prepare the water in the water storage container into an acid-base regulating solution;
the regulating solution is any one of 0.5mol/L dilute hydrochloric acid solution or 0.5mol/L sodium hydroxide solution;
the solution is injected and regulated to separate at least 5 different gradients of carbon dioxide partial pressures in water, wherein the partial pressures comprise zero gradients, and the difference of the carbon dioxide partial pressures between every two adjacent gradients is not less than 200ppm.
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| CN202311511433.9A CN117451961A (en) | 2023-11-14 | 2023-11-14 | Seawater carbon dioxide measuring instrument calibration system and calibration method thereof |
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| CN202311511433.9A CN117451961A (en) | 2023-11-14 | 2023-11-14 | Seawater carbon dioxide measuring instrument calibration system and calibration method thereof |
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