TOC (total organic carbon) water quality on-line monitoring system with self-adaptive measuring range

Abstract

The invention provides a TOC (total organic carbon) water quality on-line monitoring system with a self-adaptive range, which comprises a sample introduction assembly, an injection pump, a flow control assembly, a combustion furnace, a flow path filtering assembly, a multi-channel NDIR (non-dispersive infrared spectroscopy) detector and an upper computer, through dry combustion oxidation and NDIR detection, different calibration curves are selected to realize low-concentration and high-concentration self-adaptive tests, and the TOC water quality on-line monitoring system with the self-adaptive range is obtained. Water quality organic matter detection of pollution sources, surface water and other scenes is met, and the method can be applied to pure water detection in pharmacy, food, medical treatment and other industries; the temperature of a combustion furnace mouth is monitored, an automatic power-off protection program is started, power supply of the combustion furnace is cut off, and equipment safety risks caused by continuous temperature rise of the combustion furnace are avoided; the pressure sensor is arranged at the gas inlet of the combustion furnace, the pressure value in a gas path is automatically detected in real time, a high-salinity water sample is tested for a long time, the pressure of the gas path is increased due to crystal formation in the combustion furnace, and when the pressure value reaches a set threshold value, the combustion pipe can be warned and prompted to be maintained, and accidental risks and operation faults of equipment are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of on-line water quality monitoring, and particularly relates to an on-line TOC water quality monitoring system with an adaptive range. Background Art

[0002] Total Organic Carbon (TOC) is a comprehensive index characterizing the total amount of organic substances in water bodies, representing the sum of organic substances in water bodies. TOC can not only reflect the degree of water body pollution by organic substances, but also, as a biogenic element, reflect the situation of life activities in water bodies. Moreover, TOC plays an important role in the study of the global carbon cycle. At present, TOC determination has been widely applied to river, lake and ocean monitoring, etc., and has gradually become a conventional parameter for water quality monitoring.

[0003] The determination of TOC in water bodies usually consists of three steps: 1. Pretreatment of water samples, including sampling, filtration, acidification and removal of inorganic carbon; 2. Oxidation of TOC in water samples, and the product is CO2 which is easy to detect, which is the core of the method; 3. Detection of oxidation products. There are many detection methods for CO2 generated by TOC oxidation, such as non-dispersive infrared absorption method (NDIR: non-dispersive infrared), conductivity method, hydrogen flame ionization method, etc. Among them, the non-dispersive infrared absorption method is the most widely used.

[0004] The main technical solutions for testing water samples with different contents of organic substances at present: For water samples with a TOC value < 2 mg / L, the wet method + conductivity detector is often used, but this method is only applicable to clean water samples such as pure water and ultrapure water, and has insufficient adaptability to high-salt water samples from pollution sources. At the same time, relying on the internal folding structure of the NDIR detector to increase the optical path to improve the detection limit results in high hardware costs; For water samples with a TOC value > 6000 mg / L, by adopting a front-end quantitative system and diluting with an injection pump, however, the accuracy of the injection pump is limited, and too high dilution multiples cause large data errors; Although there is currently an NDIR detector that can achieve the detection of organic substances in water with different contents, it requires a high accuracy of the NDIR detector. Since the NDIR detector increases the optical path by multiple foldings to improve the detection limit, the hardware cost is even higher. In addition, by infinitely diluting with an injection pump, after dilution exceeds a certain multiple, the data error is large.

[0005] Therefore, it is necessary to design a TOC real-time monitoring system that can meet the measurement requirements of multiple ranges. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an on-line TOC water quality monitoring system with an adaptive range in view of the problems existing in the background art.

[0007] In order to solve the above problems, the present invention provides the following technical solutions: An adaptive range TOC water quality online monitoring system, comprising: The sample injection module is configured to use a multi-channel valve to inject samples according to the detection needs; a generating device configured to convert an input water sample into a detectable gas; The detection module includes a calibration module, an adaptive recognition module and a detection module; the calibration module is configured to store a calibration threshold, the adaptive recognition module is configured to receive input gas, and perform preliminary detection and recognition of the input gas according to the calibration threshold of the calibration module, classify the input gas according to the recognition result, and transmit the classification result to the detection module, and the detection module is configured to output detection results for different categories of recognition results according to the classification result of the recognition module.

[0008] In the present invention, the detection result can be preliminarily judged through the adaptive recognition module, and the sampling scheme can be adjusted according to the judgment result, so that the detection system can be adaptively adjusted according to the detection result of the water quality condition, thereby expanding the detection and adaptation range of the detection system.

[0009] Furthermore, the TOC water quality online monitoring system of the present invention also includes a filtration module, which uses at least two stages of filters to clean the gas generated by the generating device and transmits it to the detection module.

[0010] Furthermore, in the detection module, the calibration threshold stored in the calibration module includes at least three threshold intervals, which are: Low threshold area: TOC concentration in water sample is less than 2mg / L. Medium threshold area: TOC concentration in water samples is greater than 2 mg / L and less than 6000 mg / L. High threshold area: TOC concentration in water samples is greater than 6000 mg / L.

[0011] Furthermore, the TOC water quality online monitoring system of the present invention also includes an injection control module, one channel of the injection control module is connected to the multi-channel valve of the injection module through a syringe pump, and another channel supplies gas to the generating device.

[0012] Furthermore, the injection control module is configured to receive a detection signal from the detection module and adjust the injection control and detection strategy according to the detection signal.

[0013] Furthermore, the injection control and detection strategy in the present invention includes: When the detection result fed back by the detection module is in the low threshold area, the injection module is adjusted to low concentration injection and the injection speed is increased; When the detection module feedback shows that the detection result is in the medium threshold region, the control strategy remains unchanged, and the detection module directly outputs the detection result. When the detection module feedback shows that the detection result is in the high threshold region, the detection module is adjusted to the weak absorption wavelength mode.

[0014] Furthermore, the generating device is a combustion furnace, and a pressure sensor is provided at the air inlet of the combustion furnace, configured to monitor the pressure value in the gas path in real time. When the pressure value exceeds the safety threshold, an alarm can be issued or the air intake flow can be controlled to ensure system safety.

[0015] Furthermore, a temperature controller is provided at the sample inlet of the combustion furnace, configured to monitor the temperature at the mouth of the combustion furnace in real time. When the temperature exceeds the safety threshold, an alarm can be issued, the combustion furnace can be shut down, or cooling measures can be taken to ensure system safety.

[0016] Furthermore, the detection module includes a multi-channel NDIR detection device, and the multi-channel NDIR detection device includes filters with different wavelengths, used to select the strong absorption wavelength and the weak absorption wavelength respectively.

[0017] Furthermore, in the sampling control strategy, when the detection result is in the low threshold region, the measured concentration is set as C, and A×150 μL of water sample is injected into the combustion furnace, where A≤5, so that the water sample is combusted and oxidized into CO2; and CO2 is transported to the multi-channel NDIR detector at a carrier gas speed of B×150 mL / min, where B≤3; first, the coefficient A is adjusted to make A close to 2 / C. If A reaches the limit value of 5 and is not satisfied, then the coefficient B is adjusted so that A×B is close to 2 / C.

[0018] The present invention has the following beneficial effects: (1) Through dry combustion oxidation + NDIR detection, and by adaptively judging the concentration and selecting different calibration thresholds, the present invention realizes the adaptive testing of low concentrations and high concentrations, which not only meets the water quality organic matter detection in scenarios such as pollution sources and surface water, but can also be applied to the pure water detection in industries such as pharmaceuticals, food, and medical treatment. (2) For the temperature monitoring at the mouth of the combustion furnace, the present invention starts an automatic power-off protection program to cut off the power supply of the combustion furnace, avoiding the equipment safety risk caused by the continuous temperature rise of the combustion furnace. (3) A pressure sensor is provided at the air inlet of the combustion furnace of the present invention to automatically detect the pressure value in the gas path in real time. During the long-term testing of high-salt water samples, crystal formation in the combustion furnace will cause an increase in the gas path pressure. When the pressure value reaches the set threshold, a warning can be given to prompt the maintenance of the combustion tube, avoiding equipment accidental risks and operation failures. Description of the Drawings

[0019] Figure 1 It is the overall block diagram of Embodiment 1 of the present invention.

[0020] Figure 2 It is the flow path diagram of Embodiment 2 of the present invention.

[0021] Figure 3 It is the flow chart of Embodiment 3 of the present invention.

[0022] Reference numerals in the figure: sample assembly 1, multi-channel valve 11, aeration solenoid valve 12, aeration flowmeter 13, injection pump 2, flow control assembly 3, carrier gas input pipe 31, pressure regulating valve 32, first pressure sensor 33, carrier gas solenoid valve 34, electronic flowmeter 35, combustion furnace 4, second pressure sensor 41, temperature controller 42, humidifier 43, reagent bottle 44, first filter 45, check valve 46, flow path filter assembly 5, washing bottle 51, carrier trap 52, first type B halogen scrubber 53, cooler 54, second filter 55, second type B halogen scrubber 56, drain tank 57, multi-channel NDIR detector 6, slider transposition mechanism 7, sample injection module 100, generating device 200, detection module 300, calibration module 301, adaptive recognition module 302, detection module 303, filtering module 400, sample injection control module 500. Detailed implementation manners

[0023] The following makes a detailed description of the specific implementation manners of the present invention with reference to the accompanying drawings. It should be noted that the embodiments are only specific elaborations of the invention and should not be regarded as limitations of the invention. The purpose of the embodiments is to enable those skilled in the art to better understand and reproduce the technical solutions of the present invention. The protection scope of the present invention should still be subject to the scope defined by the claims.

[0024] Embodiment 1, an online TOC water quality monitoring system with adaptive range.

[0025] As Figure 1 shown, this embodiment provides an online TOC water quality monitoring system with adaptive range, including: a sample injection module 100, a generating device 200, and a detection module 300. The sample injection module 100 uses a multi-channel valve 11 to inject samples separately according to the detection requirements. The generating device 200 is used to convert the injected water sample into a gas that can be detected. The detection module 300 includes a calibration module 301, an adaptive recognition module 302, and a detection module 303. The calibration module 301 is used to store calibration thresholds. The adaptive recognition module 302 receives the input gas, preliminarily detects and identifies the input gas according to the calibration thresholds of the calibration module, classifies according to the recognition results, and transmits the classification results to the detection module 303. The detection module 303 outputs detection results for different types of recognition results according to the classification results of the recognition module.

[0026] The calibration thresholds include at least three threshold intervals, which are respectively: Low threshold region: The concentration value of TOC in the water sample < 2 mg / L, Medium threshold region: The concentration value of TOC in the water sample > 2 mg / L and < 6000 mg / L, High threshold region: The concentration value of TOC in the water sample > 6000 mg / L.

[0027] The on-line TOC water quality monitoring system further includes a filtration module 400, and the filtration module 400 uses the gas generated by at least two-stage filter cleaning devices 200 and transports it to the detection module 300.

[0028] The on-line TOC water quality monitoring system of the present invention further includes a sampling control module 500. One channel of the sampling control module 500 is connected to the multi-channel valve 11 of the sampling module 100 through an injection pump 2, and the other channel supplies gas to the generating device 200. The sampling control module 500 is configured to receive the detection signal of the detection module 300 and adjust the sampling control and detection strategies according to the detection signal.

[0029] The sampling control and detection strategies include: When the detection result feedback by the detection module 300 is in the low threshold region, the sampling control module 500 adjusts the sampling module 100 for low-concentration sampling and increases the sampling speed; When the detection result feedback by the detection module 300 is in the medium threshold region, the control strategy remains unchanged, and the detection module 300 directly outputs the detection result; When the detection result feedback by the detection module 300 is in the high threshold region, the detection module 300 adjusts the detection module 303 to the weak absorption wavelength mode.

[0030] Preferably, the generating device 200 is a combustion furnace. A pressure sensor is provided at the air inlet of the combustion furnace, which is configured to monitor the pressure value in the gas path in real time. When the pressure value exceeds the safety threshold, an alarm can be issued or the air intake flow can be controlled to ensure the safety of the system. Preferably, a temperature controller is provided at the sampling port of the combustion furnace, which is configured to monitor the temperature at the mouth of the combustion furnace in real time. When the temperature exceeds the safety threshold, an alarm can be issued, the combustion furnace can be shut down, or cooling measures can be taken to ensure the safety of the system.

[0031] Preferably, the detection module 303 includes a multi-channel NDIR detection device, and the multi-channel NDIR detection device includes filters with different wavelengths for respectively selecting strong absorption wavelengths and weak absorption wavelengths.

[0032] Preferably, in the sampling control strategy, when the detection result is in the low threshold region, the measured concentration is set to C, and A×150 μL of the water sample is injected into the combustion furnace, where A≤5, and the water sample is combusted and oxidized into CO2; and CO2 is transported to the multi-channel NDIR detector at a carrier gas velocity of B×150 mL / min, where B≤3; first, the coefficient A is adjusted to make A close to the value of 2 / C. If A reaches the limit value of 5 and is not satisfied, then the coefficient B is adjusted so that A×B is close to 2 / C.

[0033] Example 2, an on-line water quality monitoring system for TOC with adaptive range.

[0034] This example provides the specific flow path and detection method of the on-line water quality monitoring system for TOC with adaptive range described in Example 1, as Figure 2 shown. The on-line water quality monitoring system for TOC in this example includes a sampling component 1, an injection pump 2, a flow control component 3, a combustion furnace 4, a flow path filtering component 5, a multi-channel NDIR detector 6, and a host computer. Among them, two filters with different wavelengths are provided in the multi-channel NDIR detector 6, and the filters allow light of two specific wavelengths to pass through; it is used to select the characteristic strong absorption wavelength near 4.26 μm and the weak absorption wavelength near 2.7 μm, and let the detector test the CO2 concentration of 500 ppm and the CO2 concentration of 2000 ppm; the host computer refers to an ARM screen integrated with Linux embedded software; Three calibration curves of TOC concentration and peak area are provided in the host computer, and the calibration curves include: The first calibration curve is the curve of TOC concentration and peak area when the TOC concentration value in the water sample < 2 mg / L; The second calibration curve is the curve of TOC concentration and peak area when the TOC concentration value in the water sample > 2 mg / L and < 6000 mg / L; The third calibration curve is the curve of TOC concentration and peak area when the TOC concentration value in the water sample > 6000 mg / L; The water sample to be tested is acidified and aerated in the injection pump tube of the injection pump 2 through the sample injection assembly 1 and the flow control assembly 3 to remove the inorganic carbon in the water sample to be tested. Then, a certain volume of the water sample to be tested is injected into the combustion furnace 4 equipped with a catalyst by the injection pump 2 and heated to 680°C. The organic carbon TOC in the water sample to be tested is combusted and oxidized to generate CO2 gas. Then, the flow rate of nitrogen is controlled by the flow control assembly 3 to send the combustion gas through the flow path filter assembly 5 into the multi-channel NDIR detector 6. The multi-channel NDIR detector 6 plots the peak area according to the detected CO2 concentration. Finally, the peak area is substituted into the second calibration curve to obtain the TOC concentration. If the obtained TOC concentration < 2 mg / L, it is necessary to adjust the injection pump 2 and the flow control assembly 3, re-measure the peak area obtained after adjustment, substitute the peak area into the first calibration curve, and obtain the final TOC value; If the obtained TOC concentration > 2 mg / L and < 6000 mg / L, this TOC concentration is the final TOC value; If the obtained TOC concentration > 6000 mg / L, the multi-channel NDIR detector 6 measures the high-concentration CO2 according to the weak absorption wavelength of CO2 and plots the peak area, and substitutes the peak area into the third calibration curve to obtain the final TOC value. The present invention realizes the adaptive testing of low concentration and high concentration by adaptively judging the concentration and selecting different calibration curves, meeting the testing requirements of various application scenarios.

[0035] Among them, the multi-channel NDIR detector 6 further includes a light source, a gas chamber, a detector and a central processor; the light source and the detector are arranged at both ends of the gas chamber, and two filters with different wavelengths are arranged between the gas chamber and the detector; the gas chamber is provided with multiple channels; an air inlet hole and an air outlet hole are arranged on the side of the gas chamber, and the central processor is connected to the light source and the detector, and receives the data collected by the detector to control the on-off of the light source; among them, the detector is an infrared detector with dual detectors.

[0036] Among them, the sample injection assembly 1 includes a multi-channel valve 11, an aeration solenoid valve 12 and an aeration flowmeter 13. The multi-channel valve 11 includes a main inlet and outlet, a first inlet and outlet for resetting, a second inlet and outlet connected to the on-line water sample, a third inlet and outlet connected to the reagent bottle containing the standard sample, a fourth inlet and outlet connected to the reagent bottle containing hydrochloric acid, a fifth inlet and outlet connected to the reagent bottle containing pure water, a sixth inlet and outlet, a seventh inlet and outlet for connecting the sampling tube, an eighth inlet and outlet for draining liquid, and a tenth inlet for adding the standard sample; the main inlet and outlet of the multi-channel valve are connected to the injection tube, and the injection tube is also sequentially connected to the aeration solenoid valve 12 and the aeration flowmeter 13.

[0037] Among them, the flow control component 3 includes a carrier gas input pipe 31, a pressure regulating valve 32, a first pressure sensor 33, a carrier gas solenoid valve 34, and an electronic flowmeter 35. The carrier gas input pipe 31 is successively connected to the pressure regulating valve 32, the first pressure sensor 33, the carrier gas solenoid valve 34, and the electronic flowmeter 35. The carrier gas solenoid valve 34 is also connected to the aeration flowmeter 13 to introduce carrier gas nitrogen into the injection pipe to remove inorganic carbon in the water sample in the injection pipe.

[0038] Among them, a second pressure sensor 41 is provided at the air inlet of the combustion furnace 4 to automatically detect the pressure value in the gas path in real time. When testing high-salt water samples for a long time, crystallization in the combustion furnace 4 will cause an increase in the gas path pressure. When the pressure value reaches the set threshold, it can give an early warning to prompt maintenance of the combustion tube to avoid accidental risks and operating failures of the equipment. The electronic flowmeter 35 is connected to the humidifier 43. The humidifier 43 is connected to the reagent bottle 44 containing the CO2 absorbent. The reagent bottle 44 containing the CO2 absorbent is successively connected to the first pressure sensor 41 through the first filter 45 and the check valve 46.

[0039] A slider switching mechanism 7 is provided at the sample inlet of the combustion furnace 4 for switching the sampling pipe from the second drain waste outlet to the sample inlet of the combustion furnace. Preferably, the slider switching mechanism 7 includes a driving motor, a gear, a rack, and a slider. The driving motor is used to drive the gear, the gear and the rack are meshed, the rack is fixed to the slider, and a placement position for the sampling pipe is provided on the slider. The slider moves to the sample inlet or the drain outlet of the combustion furnace as required under the drive of the driving motor. A temperature controller 42 is provided at the sample inlet of the combustion furnace to monitor the temperature of the combustion furnace port in real time. When the furnace port temperature exceeds the normal range, an automatic power-off protection program is started to disconnect the power supply of the combustion furnace to avoid the risk of equipment safety caused by continuous heating of the combustion furnace. During the operation of the equipment, the upper computer software reads the temperature of the combustion furnace port and the pressure value at the front end of the combustion furnace in real time. When the values reach the predetermined thresholds set by the upper computer, the power supply of the combustion furnace is automatically disconnected, and at the same time, early warning and maintenance are carried out to avoid the risk of equipment safety caused by continuous heating of the combustion furnace and to avoid problems such as an increase in the gas path pressure caused by crystallization in the combustion furnace and operating failures of the combustion furnace.

[0040] Among them, the flow path filtering component 5 includes a washing bottle 51, a carrier trap 52, a first type B halogen scrubber 53, a cooler 54, a second filter 55, and a second type B halogen scrubber 56. The air outlet of the combustion furnace 4 is connected to the washing bottle 51. The washing bottle 51 is successively connected to the carrier trap 52, the first type B halogen scrubber 53, the cooler 54, the second filter 55, and the second type B halogen scrubber 56. The second filter 55 is a large filter. The liquid outlet of the cooler 54 is connected to a drain tank 57, and the drain tank 57 is also connected to the third drain waste outlet.

[0041] The host computer is connected to the main control board and the acquisition board, and the main control board and the acquisition board are respectively connected to the sample injection assembly, the injection pump, the aeration assembly, the combustion furnace, the flow control assembly, the flow path filtration assembly, and the multi-channel NDIR detector. The CO2 detected by the multi-channel NDIR detector 6 is absorbed by the CO2 absorbent to avoid environmental pollution.

[0042] Embodiment 3, an on-line detection process of a TOC water quality on-line monitoring system.

[0043] This embodiment provides the detection steps of the TOC water quality on-line monitoring system described in Embodiment 1 or Embodiment 2, as Figure 3 shown, the specific detection process is as follows: S1. The injection pump 2 sucks the water sample into the injection tube through the second inlet and outlet of the multi-channel valve 11, rinses the injection tube, and then discharges the waste liquid in the injection tube through the eighth inlet and outlet of the multi-channel valve by the injection pump; S2. The injection pump 2 sucks the water sample into the injection tube through the second inlet and outlet of the multi-channel valve 11; S3. The injection pump 2 sucks hydrochloric acid into the injection tube through the fourth inlet and outlet of the multi-channel valve 11; S4. Open the aeration solenoid valve 12 to allow the carrier gas nitrogen to enter the injection tube to remove inorganic carbon; S5. Start the slider displacement mechanism 7, switch the sampling tube to the second drain waste liquid port, use the injection pump to draw the mixed water sample from the injection tube to rinse the sampling tube, and then the slider displacement mechanism switches the sampling tube to the combustion furnace sampling port; S6. With a fixed carrier gas flow rate of 150 mL / min and a sample injection volume of 150 μL, inject the water sample after acidification and aeration treatment into the combustion furnace, and the combustion furnace oxidizes to form CO2; S7. The CO2 passes through the washing bottle 51, the carrier trap 52, the first type B halogen washer 53, the cooler 54, the second filter 55, and the second type B halogen washer 56 in sequence for filtration and then enters the multi-channel NDIR detector 6; S8. The multi-channel NDIR detector 6 automatically detects the CO2 concentration, uploads the value to the host computer software, plots the peak area, and substitutes it into the second calibration curve; ① When the calculated water sample value > 2 mg / L TOC and < 6000 mg / L TOC, the final water sample TOC value is obtained; ② When the calculated water sample value < 2 mg / L TOC and the measured concentration is C, the host computer software automatically switches to the low-concentration injection parameters and flow rate, controls the injection pump 2 and the electronic flowmeter 35 to increase the injection speed, and injects the water sample of A×150 μL into the combustion furnace again, where A ≤ 5. The water sample is combusted and oxidized into CO2, and the CO2 is transported to the multi-channel NDIR detector through the carrier gas of B×150 mL / min, where B ≤ 3. The multi-channel NDIR detector detects the CO2 concentration, uploads the value to the host computer, the host computer reads the CO2 concentration value to draw a peak shape, calculates the area of the peak, substitutes it into the first calibration curve, and obtains the final water sample TOC value; when the calculated water sample value < 2 mg / L TOC, the coefficient A is preferentially adjusted to make A close to the value of 2 / C. If A reaches the limit value of 5 and is not satisfied, then the coefficient B is adjusted to make A×B close to the value of 2 / C.

[0044] ③ When the calculated water sample value > 6000 mg / L TOC, the multi-channel NDIR detector switches to the built-in weak absorption wavelength to measure the CO2 concentration, uploads the value to the host computer, the host computer reads the CO2 concentration value to draw a peak shape, calculates the peak area, substitutes it into the third calibration curve, and obtains the final water sample TOC value; S9. Drain the remaining liquid in the injection tube to the waste liquid bucket through the eighth inlet and outlet of the multi-channel valve, and then the slider displacement mechanism switches the sampling tube to the second liquid discharge waste liquid port, and starts the injection pump to drain the remaining liquid in the sampling tube. S10. Extract pure water through the fifth inlet and outlet of the multi-channel valve 11 to clean the injection tube, and then drain the waste liquid to the waste liquid bucket through the eighth inlet and outlet of the multi-channel valve.

[0045] Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications falling within the scope of the present application. In addition, the present invention is not an invention from scratch, but an improvement and enhancement based on the prior art. Those skilled in the art can understand that the technical features not detailed in the present invention can be realized by the methods described in the prior art.

Claims

1. An on-line TOC water quality monitoring system with an adaptive range, characterized in that, include: The sample injection module is configured to use a multi-channel valve to inject samples according to the detection needs; a generating device configured to convert an input water sample into a detectable gas; The detection module includes a calibration module, an adaptive recognition module and a detection module; the calibration module is configured to store a calibration threshold, the adaptive recognition module is configured to receive input gas, and perform preliminary detection and recognition of the input gas according to the calibration threshold of the calibration module, classify the input gas according to the recognition result, and transmit the classification result to the detection module, and the detection module is configured to output detection results for different categories of recognition results according to the classification result of the recognition module.

2. An on-line TOC water quality monitoring system with an adaptive range according to claim 1, characterized in that, It also includes a filter module, which uses at least two stages of filters to clean the gas generated by the generating device and transmits the gas to the detection module.

3. An on-line TOC water quality monitoring system with an adaptive range according to claim 1, characterized in that, In the detection module, the calibration threshold stored in the calibration module includes at least three threshold intervals, which are: Low threshold area: TOC concentration in water sample is less than 2mg / L. Medium threshold area: TOC concentration in water samples is greater than 2 mg / L and less than 6000 mg / L. High threshold area: TOC concentration in water samples is greater than 6000 mg / L.

4. An on-line TOC water quality monitoring system with an adaptive range according to claim 3, characterized in that, It also includes an injection control module, one channel of which is connected to the multi-channel valve of the injection module through an injection pump, and another channel supplies gas to the generating device.

5. An on-line TOC water quality monitoring system with an adaptive range according to claim 4, characterized in that, The injection control module is configured to receive the detection signal of the detection module and adjust the injection control and detection strategy according to the detection signal.

6. An on-line TOC water quality monitoring system with an adaptive range according to claim 4, characterized in that The injection control and detection strategy includes: when the detection module feedback detection result is in the low threshold area, the injection module is adjusted to low concentration injection and the injection speed is increased; when the detection module feedback detection result is in the middle threshold area, the control strategy remains unchanged, and the detection module directly outputs the detection result; when the detection module feedback detection result is in the high threshold area, the detection module is adjusted to the weak absorption wavelength mode.

7. An on-line TOC water quality monitoring system with an adaptive range according to claim 1, characterized in that, The generating device is a combustion furnace, and a pressure sensor is provided at the air inlet of the combustion furnace, which is configured to monitor the pressure value in the gas circuit in real time.

8. An on-line TOC water quality monitoring system with adaptive range according to claim 7, characterized in that The sample inlet of the combustion furnace is provided with a temperature controller, which is configured to monitor the temperature of the combustion furnace mouth in real time.

9. An on-line TOC water quality monitoring system with an adaptive range according to claim 1, characterized in that, The detection module includes a multi-channel NDIR detection device, and the multi-channel NDIR detection device includes filters of different wavelengths for respectively selecting a strong absorption wavelength and a weak absorption wavelength.

10. An on-line TOC water quality monitoring system with an adaptive range according to claim 6, characterized in that, In the injection control strategy, when the detection result is in the low threshold area, the measured concentration is set to C, and A×150μL of water sample is injected into the combustion furnace, where A≤5, so that the water sample is burned and oxidized into CO2; and CO2 is transported to the multi-channel NDIR detector through a carrier gas speed of B×150mL / min, where B≤3; first adjust the coefficient A so that A is close to 2 / C. If A reaches the limit value 5 and is not satisfied, then adjust the coefficient B so that A×B is close to 2 / C.

Images