CN108663347B - Multi-parameter interference compensation correction system and method for optical dissolved oxygen sensor - Google Patents
Multi-parameter interference compensation correction system and method for optical dissolved oxygen sensor Download PDFInfo
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Abstract
The invention belongs to the technical field of dissolved oxygen sensor compensation and calibration, and discloses an optical dissolved oxygen sensor multi-parameter interference compensation and correction system which comprises a correction pool, a watertight connector connected with the correction pool, a gas inlet device, a dissolved oxygen sensor to be corrected, a reference dissolved oxygen sensor, a sampling device, a salinity adjusting device and a pressure adjusting device, wherein the salinity adjusting device and the pressure adjusting device are arranged on the watertight connector. According to the technical scheme, under the conditions of different water body temperatures, salinity and environmental pressure, mixed gases with different oxygen contents are sequentially introduced into the correction pool, so that a plurality of dissolved oxygen concentrations are obtained from the water body, the phase value of the dissolved oxygen sensor to be corrected and the environmental parameters of the water body are recorded, the water sample is taken, the dissolved oxygen standard value is measured by an iodometry method, the multi-parameter interference compensation correction coefficient of the dissolved oxygen sensor to be corrected is calculated, the degree of automation is improved, the sensor calibration precision, the correction precision and the in-situ measurement accuracy are improved, and the sensor has a wider application range.
Description
Technical Field
The invention belongs to the technical field of dissolved oxygen sensor compensation calibration, and discloses a high-precision complex multi-parameter environmental factor interference compensation correction method and system for an optical dissolved oxygen sensor.
Background
The dissolved oxygen is taken as an important composition and control parameter of the marine ecological environment, is an important index for measuring the quality of the seawater quality and the pollution degree of the water body, and is also an important basis for the study of the self-cleaning capability of the water body, the evaluation of the marine ecological environment and the marine science experiment. Therefore, the in-situ, rapid, accurate, stable and simple detection of the concentration of the dissolved oxygen in the seawater has important value for marine ecological environment monitoring, ecological disaster early warning and benign development of the marine pasture. At present, the dissolved oxygen Winkler analysis method is complex in procedure, time-consuming and labor-consuming, and more importantly, the non-real-time intermittent detection mode is difficult to effectively and continuously detect the dissolved oxygen in the ocean in real time. The electrochemical dissolved oxygen sensor needs a reference electrode and needs to stir the measured solution at a constant speed so as to ensure the speed of the dissolved oxygen in the water passing through the electrode film; the accuracy is low, the anti-interference capability is poor, and signal drift is easily caused by electromagnetic field interference, so that the application of the electrochemical dissolved oxygen sensor in the aspect of ocean dissolved oxygen in-situ monitoring is greatly limited.
The optical dissolved oxygen sensor based on the fluorescence quenching principle overcomes the defects of the traditional dissolved oxygen measurement, has the advantages of accurate measurement, rapidness, high selectivity, high stability, electromagnetic interference resistance, remote monitoring and the like, can realize in-situ continuous detection of the dissolved oxygen, and is widely applied to the fields of marine ecological environment monitoring, aquaculture water quality monitoring and the like. Although the optical dissolved oxygen sensor has higher stability and measurement accuracy compared with the electrochemical dissolved oxygen sensor, in the process of long-term in-situ monitoring, due to the influence of complex multi-parameter environmental factors such as temperature, salinity, depth and the like, the problem of data drift can be generated, and the measured data of the dissolved oxygen sensor needs to be compensated and corrected by the environmental factors. However, the existing compensation correction method generally has the defects of inaccurate correction value, long correction period, incapability of keeping high consistency between the correction result and the standard value in larger dissolved oxygen concentration, and the like, and mainly aims at performing compensation correction on the data interference of a dissolved oxygen sensor only by the temperature, and ignores the interference compensation correction of the influence of salinity and environmental pressure on the sensor. The traditional optical dissolved oxygen sensor temperature compensation correction method is a two-point correction method, namely, correction of oxygen-free water and saturated dissolved oxygen water, and the method is characterized in that the dissolved oxygen sensor is corrected by measuring the phase value of the dissolved oxygen sensor in the oxygen-free water (excessive sodium sulfite and a small amount of divalent cobalt salt solution are added) and the saturated dissolved oxygen water (air continuous bubbling method), and performing two-point linear fitting on the phase value and the theoretical calculated value of the dissolved oxygen in the water at the temperature, so that the dissolved oxygen sensor is corrected, but the method has the remarkable defect of low accuracy. Moreover, the traditional correction method only considers the influence of temperature on the measurement data of the sensor, does not compensate and correct the salinity, especially the interference of the environmental pressure, seriously influences the accuracy of the sensor in-situ measurement of the dissolved oxygen in the complicated coastal sea area of the environment and the high salt difference, the high turbidity and large estuary sea area, and has larger error on the profile measurement of the dissolved oxygen. The method is used for promoting the application and development of the optical dissolved oxygen sensor, promoting the business monitoring capability of the dissolved oxygen in China, improving the data quality of in-situ monitoring of the ocean dissolved oxygen, promoting the application and development of the dissolved oxygen sensor and providing a method basis for the metering and calibration work of the optical dissolved oxygen sensor in China. Therefore, it is necessary to provide a high-precision correction system and a correction method for interference compensation of complex multi-parameter environmental factors of an optical dissolved oxygen sensor.
Disclosure of Invention
Aiming at the technical problems, the invention aims to solve the remarkable problems that the existing dissolved oxygen sensor environmental factor compensation correction method has long calibration period, inaccurate standard value, single environmental factor correction, inaccurate correction algorithm model, correction result only applicable to temperature change sea areas, incapability of being applicable to complex sea areas with multi-parameter environmental factor change and the like, and provides a compensation correction system based on a temperature, salinity, depth and dissolved oxygen concentration control device and a matched multi-parameter environmental factor compensation correction method.
The following technical scheme is adopted to solve the technical problems.
The novel complex multi-parameter environmental factor compensation correction system for the dissolved oxygen sensor comprises a low-temperature constant-temperature tank with a water temperature control device, a calibration device with a stirring function, an oxygen bottle, a nitrogen bottle, two pressure reducing valves, three mass flow controllers, a salinity adjusting device with a high-precision temperature and salinity probe, a pressure adjusting device with a high-precision pressure gauge, a safety valve, a to-be-corrected dissolved oxygen sensor and a reference dissolved oxygen sensor; the correction tank with stirring function is internally provided with an air-blowing bubble stone, the interior of the correction tank is filled with ultrapure water, and the whole correction tank is arranged in a low-temperature constant-temperature tank with a water temperature control device; the correction tank is provided with a gas inlet, a gas outlet and a sampling port, and the gas outlet is connected with a safety valve; the nitrogen cylinder and the oxygen cylinder are respectively connected to the air-blowing bubble stone through a pressure reducing valve, a mass flow controller and air inlet and outlet in turn through pipelines; the correcting pool is provided with a salinity adjusting device and a pressure adjusting device which are connected with a water body through a top opening; the dissolved oxygen sensor to be corrected and the reference dissolved oxygen sensor are immersed in the water body in the standard device through the top opening of the correction tank.
The correction tank is a cylindrical barrel-shaped tank body made of a material with good pressure resistance, corrosion resistance and heat conduction, a gas inlet, a gas outlet and a sampling port are reserved on the barrel cover, the gas inlet is used as an inlet of mixed gas, the gas outlet is used as a gas outlet during air blowing, a safety valve is connected, the correction tank is automatically closed after the air blowing is finished, and the sampling port is used as a water sampling port during sampling by an iodometry; the low-temperature constant-temperature tank with the water temperature control device has the functions of heating and refrigerating, can accurately control the temperature of the water body in the correction tank, and monitors the change of the water body dissolved oxygen sensor when the reference dissolved oxygen sensor in the correction tank is used for blowing air, so that the concentration of the dissolved oxygen sensor in the water body in the correction tank is stabilized near a set value, and the concentration of the dissolved oxygen does not need to be accurately monitored; the salinity adjusting device and the pressure adjusting device at the top of the correction pool can accurately control the salinity of the water body and the environmental pressure value. The gas safety valve at the top of the correction tank can seal the correction tank and control the gas-liquid exchange between the internal water body and the external air. The safety valve prevents the internal pressure of the correction tank from being too high in the air-blowing state, and simultaneously prevents the water body in the correction tank from carrying out gas-liquid exchange with external air in the state of stopping ventilation, so that the stability of the dissolved oxygen concentration of the water body is affected.
The complex multi-parameter environmental factor compensation correction method of the optical dissolved oxygen sensor comprises the following steps:
(1) Filling ultrapure water into the correction tank, and placing the whole correction tank into a low-temperature constant-temperature tank, wherein the temperature is set to be a certain value of 0-35 ℃;
(2) Waiting for the temperature in the correction tank to be stable, regulating the gas flow ratio of the oxygen cylinder and the high-purity nitrogen cylinder through a mass flow controller, and sequentially introducing combined gases with different proportions into the correction tank to obtain a plurality of water bodies with dissolved oxygen concentration; the saturation of the dissolved oxygen in the water body is controlled between the concentration ranges of the dissolved oxygen in the practical use environment of the dissolved oxygen sensor, and the upper limit and the lower limit of the concentration ranges are required to be covered;
(3) And (3) waiting for the concentration of each dissolved oxygen in the correction pool, and recording the phase value and the water temperature value of the dissolved oxygen sensor to be corrected after the indication value of the reference dissolved oxygen sensor and the signal value of the dissolved oxygen sensor to be corrected are stable. Meanwhile, collecting a water sample from a sampling port, and measuring dissolved oxygen by an iodometric analysis method to serve as a standard value;
(4) Sequentially changing the constant temperature set value of the low-temperature constant-temperature tank into other 3 temperatures, repeating the steps (2) and (3), wherein the constant temperature is generally selected from the environment temperature range of the dissolved oxygen sensor in actual use, and two temperature gradients, namely the upper limit and the lower limit of the temperature range, are required to be covered;
(5) And calculating a temperature compensation correction coefficient of the dissolved oxygen sensor to be corrected according to the phase value of the dissolved oxygen sensor to be corrected recorded in the correction process, the temperature value of the water body in the correction tank and the dissolved oxygen concentration standard value obtained by the iodine method. The specific method comprises the following steps:
according to the phase value of the dissolved oxygen sensor to be corrected, the temperature value of the water body in the correction tank and the standard value of the dissolved oxygen concentration obtained by the iodine method at each temperature set point, a fitting formula is obtained:
[O 2 ] T ＝[(a 0 +a 1 t+a 2 t 2 )/(a 3 +a 4 φ raw )–1]/(a 5 +a 6 t+a 7 t 2 +a 8 t 3 ) (equation 1)
Wherein, [ O ] 2 ] T Is obtained by iodination method and has unit of mgL as standard value of dissolved oxygen after temperature compensation correction -1 ，φ raw For the phase value of the dissolved oxygen sensor to be corrected, t is the temperature value of the water body in the correction tank, the unit is the temperature, and the temperature compensation coefficient a is obtained by the fitting formula 0 a 1 a 2 a 3 ......a 8 。
(6) Changing the constant temperature set value of the low-temperature constant-temperature tank into 15 ℃, and obtaining saturated dissolved oxygen water by a continuous bubbling method;
(7) Changing the salinity value of the water body through a salinity control and adjustment device at the top of the correction tank, recording the salinity value, the temperature value and the dissolved oxygen indication value of the dissolved oxygen sensor in the correction tank under different water body salinity conditions after the indication value of the reference dissolved oxygen sensor in the correction tank and the signal value of the dissolved oxygen sensor to be corrected are stable, and collecting a water sample from a sampling port at the same time and measuring the dissolved oxygen as a standard value by an iodometry; the salinity compensation correction coefficient may be calculated by the salinity compensation correction formula:
[O 2 ] s ＝[O 2 ] T exp[(S-S 0 )(b 0 +b 1 t s +b 2 t s 2 +b 3 t s 3 )+b 4 (S 2 -S 0 2 )](equation 2)
Wherein, [ O ] 2 ] s The standard value of dissolved oxygen after temperature and salinity compensation and correction is obtained by an iodometry, [ O ] 2 ] T Is of equal temperatureTheoretical value of dissolved oxygen concentration, b, calculated by equation 1 under the conditions of the degree and the dissolved oxygen sensor signal value 0 、b 1 、b 2 、b 3 、b 4 For the salinity compensation correction coefficient, S is the current salinity of the water body, S 0 In the correction method, the salinity of the water body is recorded as 0, and the formula 2 is simplified as the following formula:
[O 2 ] s ＝[O 2 ] T exp[S(b 0 +b 1 t s +b 2 t s 2 +b 3 t s 3 )+b 4 S 2 ](equation 3)
Wherein t is s Is a function related to the temperature value t of the water body in the correction pool, and can be calculated by the following formula:
T s ＝ln[(298.15-t)/(273.15+t)](equation 4)
In the formula, t is the temperature value of the water body in the correction pool, and the unit is the temperature.
(8) Fixing a constant temperature set value of a low-temperature constant-temperature tank to 15 ℃, obtaining saturated dissolved oxygen water through a continuous bubbling method, changing the pressure value of the water body through an environmental pressure control device on a correction pool, recording the internal water body pressure value of a calibration device under different water body pressure conditions and the dissolved oxygen indication value of a dissolved oxygen sensor to be corrected, obtaining an environmental pressure compensation correction formula, and calculating a pressure compensation correction coefficient:
[O 2 ] d ＝[O 2 ] s +[O 2 ] s pep (equation 5)
In the formula, [ O ] 2 ] d Is the standard value of the dissolved oxygen after depth compensation and correction, [ O ] 2 ] s The theoretical value of the dissolved oxygen concentration is calculated by a formula (2) under the conditions of the same temperature, salinity and the phase value of a dissolved oxygen sensor, p is the ambient pressure, the unit is dbar, and cp is the ambient pressure compensation coefficient;
(9) By the temperature, salinity and environmental pressure correction and compensation method, the complex multi-parameter environmental factor compensation and correction calculation method of the optical dissolved oxygen sensor can be obtained:
by recording the temperature value, the salinity value, the environmental pressure value and the dissolved oxygen phase value of the dissolved oxygen sensor to be corrected, the multi-parameter environmental factor compensation correction value of the optical dissolved oxygen sensor can be obtained by the following formula:
[O 2 ]＝{[(a 0 +a 1 t+a 2 t 2 )/(a 3 +a 4 φ raw )–1]/(a 5 +a 6 t+a 7 t 2 +a 8 t 3 )}(1+pcp)exp[S(b 0 +b 1 t s +b 2 t s 2 +b 3 t s 3 )+b 4 S 2 ](equation 6)
In the formula, [ O ] 2 ]The corrected dissolved oxygen sensor readings are compensated for temperature, salinity and ambient pressure.
The water body with multiple dissolved oxygen concentrations in the step (2) is at least divided into 6 dissolved oxygen concentrations according to the dissolved oxygen concentration range of the practical use environment of the dissolved oxygen sensor, and the upper limit and the lower limit of the dissolved oxygen concentration range are required to be two dissolved oxygen concentrations, so that the dissolved oxygen saturation in the water body is generally controlled to be 0% to 120%, and the average of the dissolved oxygen concentrations is divided into 7 dissolved oxygen concentrations of 0%, 20%, 40%, 60%, 80%, 100% and 120%, and the dissolved oxygen concentration is not required to be very accurate.
And (3) monitoring the change of the dissolved oxygen concentration of the water body by using a reference dissolved oxygen sensor, and controlling the ventilation rate so that the change of the dissolved oxygen concentration is not too fast. The stirring device is kept in a working state all the time, so that the dissolved oxygen content of the water body in the calibration device is kept uniform, the speed of the stirring device is not too high, and vortex is caused otherwise. After the concentration of the dissolved oxygen reaches a preset value, stopping introducing mixed gases with different proportions, closing the stirring device, and keeping the water-gas mixer in a sealed state. After the system is stable, the sampling position is ensured to be close to the position of the dissolved oxygen sensor probe and is positioned on the same water layer.
The selection range of the constant temperature set value of the low-temperature constant-temperature tank in the step (4) is adjusted according to the actual environment temperature range of the dissolved oxygen sensor, and the temperature set value needs to cover the upper limit and the lower limit of the environment temperature range; generally taking 0-35 ℃ and covering two temperature gradients of 0 ℃ and 35 ℃;
the low-temperature constant-temperature tank with the water temperature control device can carry out accurate temperature control within a wide temperature range from minus 50 ℃ to 80 ℃, the measurement accuracy is +/-0.05 ℃, and better temperature applicability can be provided; the salinity adjusting device can accurately control salinity in a salinity range which is 0-40 degrees, the depth adjusting device can accurately control pressure in a pressure range which is very wide, the whole set of correction system can cover the whole temperature, salinity and pressure range of the actual use environment of the dissolved oxygen sensor, compared with the existing device, the device can provide more correction reference points of temperature, salinity and depth correction algorithms, the quantity and interval of the dissolved oxygen concentration, temperature points, salinity points and environmental pressure points can be flexibly set according to the change condition of the multi-parameter environmental factors of the actual use environment of the dissolved oxygen sensor, the change of a single environmental factor can be controlled, the common change of the multi-parameter environmental factors can also be controlled, joint compensation correction is carried out, the environmental condition is effectively controlled, the error caused by the sudden change of the environment is avoided, and the display value of the dissolved oxygen sensor can be kept consistent with the standard value of the dissolved oxygen in a high degree in the range of the temperature, the salinity and the environmental pressure.
According to the technical scheme, the concentration of dissolved oxygen in the correction pool is regulated by regulating the mass flow ratio of oxygen to nitrogen, and an iodine method is adopted to obtain a standard value of the concentration of the dissolved oxygen after synchronous sampling, so that compared with the existing method for calculating the standard value of the dissolved oxygen according to the solubility of oxygen in water and the method for carrying out gas correction by using combined gas, the correction precision is remarkably improved; the temperature compensation correction of the sensor is carried out by using 20 dissolved oxygen concentrations under 4 temperature conditions, and a new temperature compensation correction algorithm formula is provided by matching with the invention to carry out the temperature compensation calculation of the dissolved oxygen sensor, compared with the existing method for carrying out the temperature correction of the dissolved oxygen sensor by using more than 5 temperature conditions and more than 60 dissolved oxygen concentrations, the requirement on correction reference points is greatly reduced, the correction period is obviously shortened, the correction process is simplified, the new algorithm formula has great improvement on correction precision and simplification of the calculation process compared with the existing polynomial calculation formula, and the method can keep consistent with the dissolved oxygen standard value in a larger temperature and dissolved oxygen range; by adjusting the salinity and pressure conditions, the salinity and environmental pressure compensation correction of the optical dissolved oxygen sensor is carried out, the complex multi-parameter environmental factor compensation correction of the comprehensive system of the dissolved oxygen sensor is realized, the degree of automation is high, the calibration precision and correction precision of the sensor are improved, the in-situ measurement accuracy of the dissolved oxygen sensor is improved, the sensor has wider application range, and the sensor is suitable for the severe sea area and large estuary with larger salinity change and the monitoring of the dissolved oxygen concentration of the ocean profile with severe environmental pressure change.
According to the technical scheme, under the conditions of different water body temperatures, salinity and environmental pressure, mixed gases with different oxygen contents are sequentially introduced into the correction pool, so that a plurality of dissolved oxygen concentrations are obtained from the water body, the phase value of the dissolved oxygen sensor to be corrected and the environmental parameters of the water body are recorded, a water sample is taken, the dissolved oxygen standard value is measured by an iodometry method, the complex multi-parameter environmental factor interference compensation correction coefficient of the dissolved oxygen sensor to be corrected is calculated, simultaneous correction of the multi-parameter complex environmental factors can be realized, the degree of automation is improved, the calibration precision, the correction precision and the in-situ measurement accuracy of the sensor are improved, and the sensor has wider application range.
Drawings
Fig. 1: the invention relates to a multi-parameter interference compensation correction system structure diagram of an optical dissolved oxygen sensor.
Wherein: 1. a low-temperature constant-temperature tank; 2. a correction pool; 3. an oxygen cylinder; 4. a nitrogen cylinder; 5. a pressure reducing valve; 6. a mass flow controller; 7. a salinity adjusting device; 8. a pressure regulating device; 9. a safety valve; 10. a dissolved oxygen sensor to be corrected; 11. a reference dissolved oxygen sensor; 12. air bubble stone; 13. a liquid flow meter; 14. a sampling bottle; 15. a conduit; 16. a sampling port; 17. a gas outlet; 18. a gas inlet; 19. a watertight plug; 20. and (3) a bracket.
Detailed Description
The invention will be described in further detail with reference to the drawings and the detailed description.
As shown in fig. 1, the optical dissolved oxygen sensor correction system comprises a low-temperature constant-temperature tank 1 with a water temperature control device, a correction tank 2 with a stirring function, an oxygen bottle 3, a nitrogen bottle 4, two pressure reducing valves 5, three mass flow controllers 6, a salinity adjusting device 7 with a high-precision temperature and salinity probe, a pressure adjusting device 8 with a high-precision pressure gauge, a safety valve 9, a dissolved oxygen sensor 10 to be corrected, a reference dissolved oxygen sensor 11, an air bubble stone 12, a liquid flowmeter 13 and a sampling bottle 14.
Wherein, the correction tank 2 is a cylindrical barrel-shaped tank body made of 316 stainless steel material with good heat conduction performance, high pressure resistance and corrosion resistance, and the interior is filled with ultrapure water; a watertight connector which is convenient for connecting an external internal pipeline with an electric wire is reserved at the top of the correction tank 2, and the whole correction tank is arranged in a low-temperature constant-temperature tank 1 with a water temperature control device; the dissolved oxygen sensor 10 to be corrected and the reference dissolved oxygen sensor 11 are immersed into the water body in the correction tank through the top opening of the correction tank 2, are fixed at the central position of the water body by virtue of a bracket, are positioned close to each other and are positioned in the same water layer, and are used for monitoring the concentration of the dissolved oxygen in the water body; the correction tank 2 is provided with a salinity adjusting device 7 with a high-precision temperature and salinity probe and a pressure adjusting device 8 with a high-precision pressure gauge, and the salinity adjusting device and the pressure adjusting device are connected with a water body through an opening at the top of the correction tank and used for adjusting the salinity and the environmental pressure of the water body, recording the temperature, the salinity and the environmental pressure values of the water body and compensating and correcting the salinity and the environmental pressure by the correction method; the correction tank is provided with a gas inlet, a gas outlet and a sampling port, the gas outlet is connected with a safety valve 9 and used for protecting the calibration device from overlarge pressure and preventing the water body in the correction tank from carrying out gas-liquid exchange with external air, and the sampling port is connected with the water body at the position adjacent to the dissolved oxygen sensor probe to a sampling bottle through a conduit and used for analysis by an iodometry method and determining the concentration standard value of the dissolved oxygen in the water body; the correction tank 2 is internally provided with an air-blowing bubble stone 12, and the nitrogen cylinder 4 and the oxygen cylinder 3 are respectively connected with the correction tank through a pressure reducing valve 5, a mass flow controller 6 and a gas inlet in sequence by pipelines, so that bubbles are added to improve the water-gas mixing efficiency.
The temperature, salinity and depth compensation correction method of the optical dissolved oxygen sensor in the invention is further described below, and specifically comprises the following steps:
and (1) setting the low-temperature constant-temperature tank with the water temperature control device at a first temperature value of 0 ℃, waiting for the water temperature in the correction tank to reach a set value and stabilizing.
Step (2), changing the gas flow ratio of oxygen to nitrogen which is introduced into the correction tank through three mass flow controllers connected to the oxygen tank and the high-purity nitrogen tank, so that water bodies in the correction tank sequentially obtain 0%, 20%, 40%, 60%, 80%, 100% and 120% of total 7 dissolved oxygen concentrations;
step (3), under each dissolved oxygen concentration, using a reference dissolved oxygen sensor to monitor the dissolved oxygen concentration in the water body, stopping introducing mixed gas and closing a safety valve when the measured value reaches the vicinity of a preset value, recording the temperature value at the moment after the indication value of the reference dissolved oxygen sensor and the signal value of the dissolved oxygen sensor to be corrected in a correction pool reach stability, continuously recording the signal value of the dissolved oxygen sensor to be corrected, taking the average value of the signal values as the standard phase of the dissolved oxygen sensor to be corrected for at least 6 times, simultaneously collecting water samples which are positioned at the same water layer and close to the probe of the dissolved oxygen sensor to be corrected in parallel from a sampling port through a catheter, performing dissolved oxygen analysis by using an iodometric analysis method, and taking the average value of the signal values as the standard dissolved oxygen value of the water samples for at least 3 times;
step (4), setting the constant temperature of the low-temperature constant-temperature tank to 10 ℃, 25 ℃ and 35 ℃ in sequence, and repeating the step (2) and the step (3);
and (5) calculating a temperature compensation correction coefficient of the dissolved oxygen sensor to be corrected according to the phase value of the dissolved oxygen sensor to be corrected, the temperature value of the water body in the correction pool and the dissolved oxygen standard value obtained by an iodometry under each temperature set point, wherein the calculation method comprises the following steps:
obtaining a fitting formula according to the recorded average value of the phase of the dissolved oxygen sensor to be corrected, the temperature value and the dissolved oxygen standard value:
[O 2 ] T ＝[(a 0 +a 1 t+a 2 t 2 )/(a 3 +a 4 φ raw )–1]/(a 5 +a 6 t+a 7 t 2 +a 8 t 3 )
wherein, [ O ] 2 ] T Is obtained by iodination method and has unit of mgL as standard value of dissolved oxygen after temperature compensation correction -1 ，φ raw For the phase value of the dissolved oxygen sensor to be corrected, t is the temperature value of the water body in the calibration device, the unit is the temperature, and the temperature compensation coefficient a is obtained by the fitting formula 0 a 1 a 2 a 3 a 4 a 5 a 6 a 7 a 8 ；
Setting the constant temperature of the low-temperature constant-temperature tank with the water temperature control device at 15 ℃, waiting for the water temperature in the correction tank to reach a set value and stabilizing, introducing mixed gas (the nitrogen and oxygen ratio is the same as that of air) into ultrapure water in the correction tank at a flow rate of 1Lmin < -1 >, aerating for more than 2 hours to saturate dissolved oxygen in the mixed gas, and standing for a period of time to stabilize the dissolved oxygen to obtain saturated dissolved oxygen water.
Step (7), changing the amount of the reagents added into the water body of the correction pool through a salinity adjusting device connected to the correction pool, so that the water body in the correction pool sequentially obtains 5, 10, 15, 20, 25 and 30, and the total salinity is 6;
monitoring the salinity in the water body by using a salinity meter under each salinity, stopping introducing the reagent when the measured value reaches a preset value, recording the temperature value and the salinity value at the moment after the signal value of the dissolved oxygen sensor to be corrected reaches a stable value, continuously using the signal value of the dissolved oxygen sensor to be corrected for measuring at least 6 times, taking the average value of the signal values as the standard phase of the dissolved oxygen sensor to be corrected, simultaneously collecting at least 3 groups of water samples in parallel from a sampling port, carrying out dissolved oxygen analysis by using an iodine analysis method, and taking the average value of the signal values as the standard dissolved oxygen value of the water samples;
step (9), according to the recorded average value of the phase of the dissolved oxygen sensor to be corrected, the temperature value, the salinity value and the dissolved oxygen standard value, a salinity compensation correction formula can be obtained, and the salinity compensation correction coefficient of the dissolved oxygen sensor to be corrected is calculated:
[O 2 ] s ＝[O 2 ] T exp[S(b 0 +b 1 t s +b 2 t s 2 +b 3 t s 3 )+b 4 S 2 ]
in the formula, [ O ] 2 ] s The standard value of dissolved oxygen after temperature and salinity compensation and correction is obtained by an iodometry, [ O ] 2 ] T For the theoretical value of the dissolved oxygen concentration obtained by calculation of the formula (1) under the condition of the same temperature and the signal value of the dissolved oxygen sensor, S is the current salinity of the water body, six linear simultaneous equations can be established according to the formula, and the salinity correction coefficient b of the sensor can be obtained by solving the six linear simultaneous equations 0 、b 1 、b 2 、b 3 、b 4 。
Setting the constant temperature of a low-temperature constant-temperature tank with a water temperature control device to 15 ℃, waiting for the temperature of water in a correction tank to reach a set value and stabilizing, and obtaining saturated dissolved oxygen water by adopting the method of the step (6); collecting at least 3 groups of water samples in parallel from the sampling port, analyzing the dissolved oxygen by using an iodometric analysis method, and taking the average value as the standard dissolved oxygen value of the water body.
Step (11), changing the pressure value of the water body in the correction tank through an environmental pressure control and adjustment device at the top of the correction tank, so that the water body in the correction tank sequentially obtains 0.1MPa, 0.5MPa and 1MPa for 3 total pressures; under each pressure, monitoring the pressure in the water body by using a pressure gauge, stopping pressurizing when the measured value reaches a preset value, recording the water body pressure value, the temperature value and the salinity value in the correction pool under different water body pressure conditions and the dissolved oxygen indication value of the dissolved oxygen sensor calibrated by the temperature salinity compensation correction method after the indication value of the dissolved oxygen sensor to be corrected reaches a stable value, and calculating a pressure compensation correction coefficient according to the water body dissolved oxygen concentration standard value before pressurizing, the water body pressure value and the indication value of the dissolved oxygen sensor to be calibrated to obtain an environmental pressure compensation correction formula:
[O 2 ] d ＝[O 2 ] s +[O 2 ] s pcp
in the formula, [ O ] 2 ] d Is the standard value of the dissolved oxygen after depth compensation and correction, [ O ] 2 ] s For the sensor phase value of the same temperature, salinity and dissolved oxygen to pass through the common partThe theoretical value of the concentration of the dissolved oxygen obtained by calculation in the formula (2) is p, the unit is dbar, and cp is an ambient pressure compensation coefficient.
The temperature, salinity and environmental pressure compensation correction coefficient obtained by the calculation method can obtain the comprehensive compensation correction calculation formula of the temperature, salinity and environmental pressure of the optical dissolved oxygen sensor:
[O 2 ]＝{[(a 0 +a 1 t+a 2 t 2 )/(a 3 +a 4 φ raw )–1]/(a 5 +a 6 t+a 7 t 2 +a 8 t 3 )}(1+pcp)exp[S(b 0 +b 1 t s +
b 2 t s 2 +b 3 t s 3 )+b 4 S 2 ]
in the formula, [ O ] 2 ]The corrected dissolved oxygen sensor indication value is compensated for temperature, salinity and environmental pressure, t is the temperature, S is the current salinity of the water body, and p is the water body pressure;
when the corrected optical dissolved oxygen sensor is measured at any temperature, salinity, ambient pressure and dissolved oxygen concentration in the correction range, the multi-parameter ambient factor compensation correction value of the optical dissolved oxygen sensor can be obtained by the calculation formula only by recording the temperature value, the salinity value, the ambient pressure value and the dissolved oxygen phase value of the dissolved oxygen sensor to be corrected of the water body.
The examples merely illustrate the technical solution of the invention and do not limit it in any way; although the invention has been described in detail with reference to the foregoing embodiments, it will be apparent to one skilled in the art that modifications may be made to the technical solutions described in the foregoing embodiments, or equivalents may be substituted for some of the technical features thereof; such modifications and substitutions do not depart from the spirit and scope of the corresponding technical solutions.
Claims (2)
1. The multi-parameter interference compensation correction method for the optical dissolved oxygen sensor is characterized by comprising the following steps of: (1) setting a correction pool low temperature constant temperature; (2) Introducing mixed gases with different proportions into the correction tank to obtain water bodies with different dissolved oxygen concentrations; (3) After waiting for correcting the concentration of dissolved oxygen in the pool and the indication value of the reference dissolved oxygen sensor and the signal value of the dissolved oxygen sensor to be corrected are stable, recording the phase value of the dissolved oxygen sensor to be corrected and the temperature value of the water body; meanwhile, collecting a water sample, and measuring dissolved oxygen by an iodine analysis method to serve as a standard value; (4) Sequentially setting the constant temperature of the correction tank to be 3 other temperatures different from the temperature in the step (1), and repeating the step (2) and the step (3); (5) Calculating a temperature compensation correction coefficient of the dissolved oxygen sensor to be corrected according to the phase value of the dissolved oxygen sensor to be corrected recorded in the correction process, the temperature value of the water body in the correction tank and the dissolved oxygen concentration standard value obtained by an iodine method;
the calculation method of the step (5) comprises the following steps: according to the phase value of the dissolved oxygen sensor to be corrected, the temperature value of the water body in the correction tank and the standard value of the dissolved oxygen concentration obtained by the iodine method at each temperature set point, a fitting formula is obtained:
wherein, [ O ] 2 ] T Is obtained by iodination method and has unit of mgL as standard value of dissolved oxygen after temperature compensation correction -1 ，For the phase value of the dissolved oxygen sensor to be corrected, t is the temperature value of the water body in the correction tank, the unit is the temperature, and the temperature compensation coefficient a is obtained by the fitting formula 0 a 1 a 2 a 3 ......a 8 ；
Setting the constant temperature of the correction tank to 15 ℃, obtaining saturated dissolved oxygen water, changing salinity, waiting for the stable indication value of a reference dissolved oxygen sensor in the correction tank and the signal value of the dissolved oxygen sensor to be corrected, recording the salinity value, the temperature value and the dissolved oxygen indication value of the dissolved oxygen sensor in the correction tank under different water salinity conditions, collecting a water sample from a sampling port, measuring the dissolved oxygen by an iodometry as a standard value, and calculating a salinity compensation correction coefficient by using the following salinity compensation correction formula:
[O 2 ] s ＝[O 2 ] T exp[(S-S 0 )(b 0 +b 1 t s +b 2 t s 2 +b 3 t s 3 )+b 4 (S 2 -S 0 2 )](equation 2)
Wherein, [ O ] 2 ] s The standard value of dissolved oxygen after temperature and salinity compensation and correction is obtained by an iodometry, [ O ] 2 ] T B is a theoretical value of dissolved oxygen concentration obtained by calculating in a formula 1 under the condition of the same temperature and the signal value of a dissolved oxygen sensor 0 、b 1 、b 2 、b 3 、b 4 For the salinity compensation correction coefficient, S is the current salinity of the water body, S 0 In the correction method, the salinity of the water body is recorded as 0, and the formula 2 is simplified as the following formula:
[O 2 ] s ＝[O 2 ] T exp[S(b 0 +b 1 t s +b 2 t s 2 +b 3 t s 3 )+b 4 S 2 ](equation 3)
Wherein t is s Is a function related to the temperature value t of the water body in the correction pool, and can be calculated by the following formula: t is t s ＝ln[(298.15-t)/(273.15+t)](equation 4)
Wherein t is the temperature value of the water body in the correction pool, and the unit is the temperature;
setting the constant temperature of the correction tank to 15 ℃, obtaining saturated dissolved oxygen water, changing the water pressure value, recording the water pressure value in the correction tank and the dissolved oxygen indication value of the dissolved oxygen sensor to be corrected under different water pressure conditions, obtaining an environmental pressure compensation correction formula, and calculating a pressure compensation correction coefficient:
[O 2 ] d ＝[O 2 ] s +[O 2 ] s pep (equation 5)
In the formula, [ O ] 2 ] d Is the standard value of the dissolved oxygen after depth compensation and correction, [ O ] 2 ] s Is the same asCalculating a theoretical value of dissolved oxygen concentration obtained through a formula (2) under the conditions of equal temperature, salinity and a phase value of a dissolved oxygen sensor, wherein p is the ambient pressure, the unit is dbar, and cp is an ambient pressure compensation coefficient;
calculating to obtain a multi-parameter environmental factor compensation correction value of the optical dissolved oxygen sensor by recording a temperature value, a salinity value, an environmental pressure value and a dissolved oxygen phase value of the dissolved oxygen sensor to be corrected of the water body:
in the formula, [ O ] 2 ]Compensating corrected dissolved oxygen sensor readings for temperature, salinity and ambient pressure;
the compensation correction method is completed by using an optical dissolved oxygen sensor multi-parameter interference compensation correction system, wherein the compensation correction system comprises a correction pool, a watertight connector connected with the correction pool, a gas inlet device, a dissolved oxygen sensor to be corrected, a reference dissolved oxygen sensor, a sampling device, a salinity adjusting device and a pressure adjusting device, wherein the salinity adjusting device and the pressure adjusting device are arranged on the watertight connector, and the dissolved oxygen sensor to be corrected and the reference dissolved oxygen sensor are positioned at the same height;
the salinity regulating device is provided with a high-precision temperature and salinity probe, and the pressure regulating device is provided with a high-precision pressure gauge;
the sampling device comprises a guide pipe and a sampling bottle, the watertight connector is provided with a sampling port, the guide pipe is led into the correction pool through the sampling port, and the port of the guide pipe in the correction pool is the same as the dissolved oxygen sensor to be corrected in height;
the gas inlet device comprises an oxygen cylinder, a nitrogen cylinder and a gas pipeline, the outlets of the oxygen cylinder and the nitrogen cylinder are provided with pressure reducing valves, the gas pipeline is provided with a mass flow control valve, the watertight plug connector is provided with a gas inlet, and the gas pipeline is led into the correction tank through the gas inlet.
2. The method for compensating for the multi-parameter interference of the optical dissolved oxygen sensor according to claim 1, wherein: the dissolved oxygen concentration in step (2) is seven of 0%, 20%, 40%, 60%, 80%, 100% and 120%.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2247644A1 (en) * | 1997-09-18 | 1999-03-18 | Solinst Canada Limited | Apparatus for measuring and recording data from boreholes |
| CN104515761A (en) * | 2014-12-20 | 2015-04-15 | 国家海洋局第二海洋研究所 | High-precision optical dissolved oxygen sensor calibration method and device |
| KR101526217B1 (en) * | 2014-12-01 | 2015-06-05 | 길주형 | On-Line Smart DO Analyzer |
| CN107202763A (en) * | 2017-06-17 | 2017-09-26 | 山东省科学院海洋仪器仪表研究所 | Optical dissolved oxygen sensor thermohaline correction algorithm and new caliberating device |
| CN207036693U (en) * | 2017-06-17 | 2018-02-23 | 山东省科学院海洋仪器仪表研究所 | A kind of new caliberating device of optical dissolved oxygen sensor |
| CN208537414U (en) * | 2018-07-09 | 2019-02-22 | 山东省科学院海洋仪器仪表研究所 | Optical dissolved oxygen sensor multi-parameter interference compensation corrects system |
-
2018
- 2018-07-09 CN CN201810747229.XA patent/CN108663347B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2247644A1 (en) * | 1997-09-18 | 1999-03-18 | Solinst Canada Limited | Apparatus for measuring and recording data from boreholes |
| KR101526217B1 (en) * | 2014-12-01 | 2015-06-05 | 길주형 | On-Line Smart DO Analyzer |
| CN104515761A (en) * | 2014-12-20 | 2015-04-15 | 国家海洋局第二海洋研究所 | High-precision optical dissolved oxygen sensor calibration method and device |
| CN107202763A (en) * | 2017-06-17 | 2017-09-26 | 山东省科学院海洋仪器仪表研究所 | Optical dissolved oxygen sensor thermohaline correction algorithm and new caliberating device |
| CN207036693U (en) * | 2017-06-17 | 2018-02-23 | 山东省科学院海洋仪器仪表研究所 | A kind of new caliberating device of optical dissolved oxygen sensor |
| CN208537414U (en) * | 2018-07-09 | 2019-02-22 | 山东省科学院海洋仪器仪表研究所 | Optical dissolved oxygen sensor multi-parameter interference compensation corrects system |
Non-Patent Citations (4)
| Title |
|---|
| Hall O P 等.Multivariate experimental methodology applied to the calibration of a Clark type oxygen sensor.Analytica Chimica Acta.1997,第355卷(第1期),第43-53页. * |
| HIROSHI U 等.In Situ Calibration of Optode-Based Oxygen Sensors.Journal of Atmospheric and Oceanic Technology.2008,第25卷(第12期),Journal of Atmospheric and Oceanic Technology. * |
| 王凤阳,陆彦彬,刘林.YSI 58型溶解氧测定仪的调试与应用.天津化工.2001,(第05期),全文. * |
| 荧光猝灭法溶解氧传感器实验室校准方法研究;郑旻辉;潘建明;杨俊毅;谢尚微;;海洋技术学报(第01期);全文 * |
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