CN206223771U - A kind of seawater total alkalinity on-line monitoring system - Google Patents

Abstract

The utility model belongs to the technical field of marine monitoring, in particular to an instrument and equipment which can be used for on-line monitoring of seawater total alkalinity. The seawater total alkalinity online monitoring system mainly includes a flow path system, a monitoring device, and a control system; the flow path system is used to complete the sampling, titration, calibration, waste discharge, and flushing processes of seawater samples; The monitoring device is connected with the flow path system for monitoring the solution state of the flow path system, and sends the monitored temperature, salinity, and pH data to the control system; the control system is connected with the flow path system and the monitoring device, and uses It is used to control the work of the flow system, process the data sent by the monitoring device, complete the online monitoring, and output the monitoring results of the total alkalinity of seawater. The online monitoring system for total alkalinity of seawater of the utility model can realize online monitoring and analysis of total alkalinity of seawater without manual operation, is highly automated, and has high measurement accuracy.

Description

A seawater total alkalinity online monitoring system

technical field

The utility model belongs to the technical field of marine monitoring, in particular to an instrument and equipment which can be used for on-line monitoring of seawater total alkalinity.

Background technique

Total Alkalinity (TA) is an important parameter to characterize the carbonate system of seawater. Accurate determination of seawater TA is of great significance for understanding marine biogeochemical processes such as marine carbon cycle and seawater acidification. The determination methods of total alkalinity in seawater mainly include single-point pH determination, iodometric method, neutralization titration, and pH potentiometric titration. Compared with other methods, potentiometric titration is widely used because of its highest precision and accuracy. The measurement method recommended in my country's marine industry standard "HY/T 178-2014 Determination of Seawater Alkalinity" is pH potentiometric titration. At present, the commonly used seawater total alkalinity instruments mainly include AS-ALK2 from Apollo Company of the United States, VINDTA 3S from Mariaanda of Germany, and ATT-15 from Kimoto Company of Japan. For indoor applications, online analysis and monitoring of seawater cannot be completed. At present, the in-situ monitoring of total alkalinity in seawater mainly includes the total alkalinity measuring instrument of Xiamen University (patent publication number: CN101221131). point method. There is also a total alkalinity online testing device (authorized announcement number: CN 201926626 U), although this device can complete the online monitoring of alkalinity, but due to the limitation of the method, the accuracy and precision of the device are not high, and it has not involved The influence of seawater salinity on factors such as H ⁺ activity, so it is not suitable for the analysis of seawater samples. At present, there is no relatively mature instrument that can complete the online measurement of total alkalinity in seawater.

Utility model content

Aiming at the shortage of existing instruments, the utility model is based on the principle of pH potentiometric titration method, and provides an online measurement system of total alkalinity of seawater with high degree of automation, short response time and good precision and accuracy, which is suitable for long-term online measurement of total alkalinity of seawater Real-time analysis and monitoring. At the same time, the temperature and salinity are calibrated through the seawater salinity sensor inside the instrument. The instrument of the utility model is also suitable for estuaries and areas with serious seawater pollution.

The technical scheme adopted by the utility model is: an online monitoring system for total alkalinity of seawater, which mainly includes a flow path system, a monitoring device, and a control system; the flow path system is used to complete the sampling, titration, Calibration, draining, and flushing processes; the monitoring device is connected to the flow system for monitoring the solution state of the flow system, and sends the monitored temperature, salinity, and pH data to the control system; the control The system is connected with the flow system and the monitoring device system, and is used to control the work of the flow system, process the data transmitted from the monitoring device, complete the online monitoring, and output the monitoring results of the total alkalinity of seawater to the outside.

The flow path system includes a reaction tank, a sampling device, a pH buffer solution calibration device, a reaction tank cleaning device, a stirring device, a waste discharge and waste liquid collection device; the sampling device, a pH buffer solution calibration device, a reaction The tank cleaning device and the waste discharge and waste liquid collection device are all connected to the reaction tank; the stirring device is arranged at the bottom of the reaction tank.

The sampling device includes a seawater sample sampling device and an HCl solution sampling device.

The seawater sample sampling device is composed of a plunger pump, a multi-way valve and a pipeline. After the sampling is completed, the seawater sample is injected into the reaction tank.

The HCl solution sampling device uses a plunger pump to extract the HCl solution and inject it into the reaction tank to complete the titration work.

The pH buffer solution calibration device is composed of a peristaltic pump and a multi-way valve, and sequentially injects different pH buffer solution calibrations (various types) into the reaction pool to calibrate the pH/potential measurement system.

The reaction tank cleaning device is composed of a peristaltic pump and a multi-way valve, which is used to inject the flushing liquid into the reaction tank, and complete the cleaning under the agitation of the stirring device. At the same time, the cleaning liquid of the plunger pump of the seawater sample sampling device can be completed by switching the cleaning liquid through the multi-way valve. In addition, through the reaction tank cleaning device, the electrode soaking solution can also be injected into the reaction tank to keep the electrode wet during the measurement gap, so as to preserve the electrode for a long time and realize the maintenance of the pH electrode.

The stirring device includes an electromagnetic stirring device and a stirring magnet.

The waste discharge and waste liquid collection device is composed of a solenoid valve, a peristaltic pump and a waste liquid tank, and discharges the waste liquid in the reaction tank to the waste liquid tank for recycling.

The monitoring device includes a temperature-salt sensor and a pH/potential electrode. The pH/potential electrode can respond quickly to H ⁺ , and can continuously monitor online for a long time after one calibration without frequent maintenance, and is suitable for online monitoring. The solution status of the flow path system is monitored through the above sensors, and the monitoring system sends data such as temperature, salinity, pH, etc. to the whole system.

The control system completes the processes of calibration, sampling, titration, waste discharge, and flushing by controlling the plunger pump, peristaltic pump, and solenoid valve of the flow system; at the same time, the recorded HCl volume and the data information sent by the monitoring device are compared Data processing, through the built-in Gran graphics processing program to determine the volume of HCl at the end of the titration, correct the temperature and salinity, calculate the value of the total alkalinity of the seawater, complete the online monitoring, and output the monitoring results of the total alkalinity of the seawater.

The online monitoring system for total alkalinity of seawater of the utility model can realize online monitoring and analysis of total alkalinity of seawater without manual operation, is highly automated, has high measurement accuracy, and can be integrated into large-scale online monitoring systems, such as stations and buoys. Moreover, the system has the characteristics of modularization, can be matched independently, and has a wide range of adaptation.

Description of drawings

Fig. 1 is the structural diagram of the seawater total alkalinity online monitoring system of the utility model.

detailed description

The online monitoring system for seawater total alkalinity of the present utility model will be described and elaborated in detail below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 1, the utility model online monitoring system for total alkalinity in seawater is mainly composed of a flow system, a monitoring device, and a control system.

The flow path system includes a reaction tank 1, a first multi-way valve 2, a first plunger pump 3, a second plunger pump 4, an electromagnetic stirring device 7, a first peristaltic pump 8, a second multi-way valve 9, a second peristaltic Pump 10 , third multi-way valve 11 , third peristaltic pump 12 , waste liquid tank 13 , first solenoid valve 14 and second solenoid valve 15 .

Reaction pool 1 is the reaction vessel for system calibration, titration and other processes, and is made of strong superhydrophobic and oleophobic quartz glass material. A magnet is placed inside the reaction pool, and the stirring work is completed under the action of the electromagnetic stirring device 7 during the reaction.

The seawater sample sampling device composed of the first plunger pump 3 , the first multi-way valve 2 , the first solenoid valve 14 and the polytetrafluoroethylene tube completes high-precision sampling and injects the seawater sample into the reaction pool 1 .

The HCl solution sampling device composed of the second plunger pump 4 can accurately extract HCl solution (about 0.100 mol/L, calibrated with Na ₂ CO ₃ solution in advance), and inject it step by step into the reaction pool 1 under the control of the control system , complete the titration work.

The reaction tank cleaning device composed of the first peristaltic pump 8 and the second multi-way valve 9 injects the flushing liquid (low CO ₂ content) into the reaction tank, and completes the cleaning under the stirring of the magnet and the electromagnetic stirring device. At the same time, the cleaning of the first plunger pump 3 can be completed by switching the cleaning fluid through the first multi-way valve 2 .

The reaction tank cleaning device can also be used as a pH electrode maintenance device. The electrode soaking solution is injected into the reaction tank 1 through the first peristaltic pump 8 and the second multi-way valve 9, and the electrode is kept wet during the measurement gap to preserve the electrode for a long time.

The pH buffer solution calibration device composed of the second peristaltic pump 10 and the third multi-way valve 11 sequentially injects different pH buffer solution calibrations (various types) into the reaction pool 1 to calibrate the pH/potential measurement system.

The waste liquid tank 13 is connected with the reaction tank, and the waste liquid in the reaction tank is discharged to the waste liquid tank through the second solenoid valve 14 and the third peristaltic pump 12 for recycling.

The monitoring device consists of a high-precision temperature-salt sensor 6 and a high-precision pH/potential electrode 5. The pH/potential electrode 5 used can respond quickly to H ⁺ . After one calibration, it can continuously monitor online for a long time without frequent maintenance, and is suitable for online monitoring. The above sensors monitor the solution status of the flow path system, and the monitoring system sends data such as temperature, salinity, pH, etc. to the control system of the whole machine.

The control system completes the process of calibration, sample injection, titration, waste discharge, and flushing by controlling the high-precision digital plunger pump, high-precision peristaltic pump, multi-port valve, and solenoid valve of the flow system; at the same time, the recorded HCl volume and the monitoring The data information sent by the device is processed, and the volume of HCl at the end of the titration is determined by means of Gran mapping and second differential, and the temperature and salinity are corrected to calculate the value of the total alkalinity of seawater, complete online monitoring, and output to the outside world Monitoring results of total alkalinity in seawater.

The plunger pumps in the flow system all adopt high-precision digital plunger pumps, and the peristaltic pumps are high-precision peristaltic pumps.

The seawater total alkalinity online monitoring system of the present utility model, its initial test process is as follows:

1. Waste liquid: Before use, there is pH electrode soaking liquid in the reaction tank 1, so it needs to be discharged and rinsed, and the liquid in the reaction tank is drained through the second solenoid valve 15 and the third peristaltic pump 12.

2. Flushing: The flushing liquid is injected into the reaction tank 1 through the first multi-way valve 2 through the first plunger pump 3 and the first electromagnetic valve 14, and the first plunger pump 3 and the For the flushing of the reaction pool, the second solenoid valve 15 and the third peristaltic pump 12 control the discharge.

3. Calibration: Under the control of the second peristaltic pump 10 and the third multi-way valve 11, pH buffer solution is injected sequentially for pH electrode calibration. After the calibration is completed, the second solenoid valve 15 and the third peristaltic pump 12 control the discharge.

4. The seawater sample is injected into the reaction tank through the first plunger pump 3 and the first electromagnetic valve 14, and then discharged.

5. The flushing liquid is injected into the reaction pool by the first peristaltic pump 8 through the second multi-way valve 9, and the flushing of the reaction pool, the pH/point electrode 5 and the temperature and salt sensor 6 is completed under the action of the electromagnetic stirring device 7 and the magnet. Monitor the change of the conductivity of the solution through the temperature and salt sensor, and check whether the pipeline and the reaction pool are flushed.

6. The seawater sample is injected into the reaction tank through the first multi-way valve 2 through the first plunger pump 3, and slowly injects HCl from the second plunger pump 4, records the volume of the added HCl solution, and monitors the pH/potential electrode and temperature, Salinity sensor changes, over titrated to pH 2.50. The control system plots the V _HCl and pH/potential data, and processes them through the built-in Gran plotting program to obtain the data of the titration end point. At the same time, according to the monitoring results of the temperature and salt sensor, the final inversion calculates the total alkalinity value.

For the first measurement, three titrations will be carried out, and when the deviation of the results of the three determinations is less than 0.2%, the entire online monitoring system will continue to operate according to the settings. If the deviation of the result is large, recalibrate the electrode and repeat the titration until the deviation of the three results is less than 0.2%.

The initial monitoring is qualified, and the entire online monitoring system automatically runs according to the settings to monitor the total alkalinity of seawater.

During the continuous monitoring of the system, a monitoring is completed in the order of 4→5→6. If the result is abnormal, the system will alarm.

After the test is completed, the flushing liquid is injected into the reaction pool through the first multi-way valve 2 through the first plunger pump 3, and the flushing of the flow path system is completed under the action of electromagnetic stirring. Through the first peristaltic pump 8 and the second multi-way valve 9, the electrode soaking solution is injected into the reaction cell to protect the electrodes.

Since the pH/potential electrode used is a highly stable pH electrode, frequent calibration is not required. In the case of long-term application, the system will calibrate the pH electrode from time to time before sampling according to the test frequency, seawater state and use settings.

Claims (8)

1. a kind of seawater total alkalinity on-line monitoring system, it is characterised in that：Mainly include flow path system, monitoring device and control System processed；Described flow path system is used to complete sample introduction, titration, calibration, waste discharge, the flushing process of seawater sample；Described prison Survey device to be connected with flow path system, the solution state for monitoring flow path system, and temperature, salinity, the pH data that will be monitored Send to control system；Described control system is connected with flow path system and monitoring device, the work for controlling flow path system, And the data for transmitting monitoring device are processed, on-line monitoring is completed, externally the monitoring result of output seawater total alkalinity.

2. seawater total alkalinity on-line monitoring system according to claim 1, it is characterised in that：Described flow path system includes Reaction tank, sampling device, pH cushioning liquid calibrating installation, reaction tank cleaning device, agitating device, waste discharge and waste collection dress Put；Described sampling device, pH cushioning liquid calibrating installation, reaction tank cleaning device and waste discharge and waste collecting device with instead Pond is answered to connect；Agitating device is arranged on reaction tank bottom.

3. seawater total alkalinity on-line monitoring system according to claim 2, it is characterised in that：Described sampling device is main It is made up of plunger displacement pump, including seawater sample sampling device and HCl solution sampling device.

4. seawater total alkalinity on-line monitoring system according to claim 3, it is characterised in that：Described seawater sample sample introduction Device also includes multiple-way valve, magnetic valve.

5. seawater total alkalinity on-line monitoring system according to claim 2, it is characterised in that：Described pH cushioning liquid school Standard apparatus and reaction tank cleaning device are constituted by peristaltic pump and multiple-way valve.

6. seawater total alkalinity on-line monitoring system according to claim 2, it is characterised in that：Described agitating device includes Electromagnetic mixing apparatus and stirring magneton.

7. seawater total alkalinity on-line monitoring system according to claim 2, it is characterised in that：Described waste discharge and waste liquid are received Acquisition means are made up of magnetic valve, peristaltic pump and waste liquid tank, and the waste liquid in reaction tank is expelled into waste liquid tank, to recycle.

8. the seawater total alkalinity on-line monitoring system according to claim any one of 1-7, it is characterised in that：Described monitoring Device includes thermohaline sensor and pH/ potential electrodes.