Carbon monitoring system and method for organic carbon element

Abstract

The invention relates to an organic carbon element carbon monitoring system and method, and belongs to the technical field of carbon detection. The organic carbon element carbon monitoring system comprises a first switching module, a quantitative pipeline, a second switching module, a third switching module and an output pipeline which are connected in sequence, the first switching module is used for enabling the inlet of the quantitative pipeline to be selectively communicated with the standard solution supply pipeline or the carrier liquid supply pipeline; the second switching module is used for selectively communicating the outlet of the quantitative pipeline with the waste liquid collecting pipeline or the inlet of the third switching module; the third switching module is used for enabling the inlet of the output pipeline to selectively communicate with the gas supply pipeline or the outlet of the second switching module; an outlet of the output pipeline extends into the branch pipe, and the branch pipe is communicated with the optical channel through the first opening. The automatic titration calibration device avoids the influence of manual operation, has an automatic titration calibration function and is good in repeatability. In addition, interference of water on carbon dioxide measurement is eliminated, and errors are reduced.

Description

Technical Field

[0001] The present application belongs to the field of carbon detection technology, and specifically relates to an organic carbon element carbon monitoring system and method. Background Art

[0002] The carbonaceous components in aerosols are classified according to chemical composition, mainly including organic carbon (OC), elemental carbon (EC) and a small amount of carbonate carbon (CC). OC contains various organic matter and comes from primary emissions and secondary conversions. EC is a single carbon substance and mainly comes from incomplete combustion of fuels. Total carbon (TC) can be approximately regarded as the sum of OC and EC. Black carbon (BC) is a substance with strong light absorption characteristics in the carbonaceous components.

[0003] There are three main methods for analyzing carbonaceous aerosols: thermal method, optical method and thermal-optical correction method.

[0004] (1) The inherent defect of the thermal method is that it cannot solve the problem of carbonization of part of the organic carbon (OC) into elemental carbon (EC) during the thermal decomposition process, which leads to the inability to accurately separate OC and EC.

[0005] (2) Optical method: It roughly assumes that the light absorption of other components of the particles is negligible relative to the light absorption of EC. The measurement is actually the sum of EC and light-absorbing OC.

[0006] (3) The thermal-optical correction method is based on the thermal method for measuring OC and EC. It introduces the optical correction method and uses the change in laser intensity on the filter membrane during the thermal decomposition process as a basis to accurately determine the split point between OC and EC. It is currently the most widely used and recognized mature carbonaceous aerosol analysis method in the world.

[0007] Most of the current thermo-optical organic carbon elemental carbon analyzers are based on the thermal-optical correction method, combined with the non-dispersive infrared (NDIR) measurement technology, to achieve online measurement of total carbon (TC), organic carbon (OC) and elemental carbon (EC) in particulate matter. The analyzer enriches particulate matter on the high-temperature resistant quartz filter membrane in the heating furnace through automatic sampling, purges the pipeline with pure He gas, and starts the anaerobic and aerobic thermal analysis processes in turn. The generated gas is converted into CO2 through a high-temperature oxidation furnace (conversion channel) and enters the NDIR analysis module. During the thermal analysis process, the split point of OC and EC can be determined based on the change in laser intensity. After the thermal analysis is completed, the He / CH4 internal standard gas enters the pipeline through a quantitative loop, is oxidized to CO2 by the oxidation furnace, and enters the NDIR. The OC and EC concentrations are calculated by the ratio of the CO2 peak area before and after the split point to the internal standard peak area.

[0008] At present, the thermo-optical organic carbon element carbon online monitoring products mainly rely on manual operation for standard solution titration and calibration. Usually, a 10μL range micro-syringe is used to manually extract 1μL, 2μL, 5μL or other standard solutions of different volumes or concentrations for titration testing and calibration. This manual operation will be affected by the differences in operating techniques of different people, and sometimes it will introduce subtle bubbles. These factors will lead to poor measurement repeatability and large errors.

[0009] In addition, the quartz heating furnace needs to be disassembled each time the standard solution is titrated. If some repetitive tests or linear tests of different concentrations are performed, the quartz heating furnace needs to be disassembled and assembled repeatedly, which easily increases the risk of leakage.

[0010] In addition, every time the quartz heating furnace is disassembled, the filter membrane lying flat on the front end of the liner will be exposed to the air, which will enrich a certain amount of VOCs in the air and also cause errors in the measurement results. Summary of the invention

[0011] In order to solve the deficiencies in the above-mentioned prior art solutions, the present invention provides an organic carbon element carbon monitoring system and method.

[0012] The objective of the present invention is achieved through the following technical solutions:

[0013] In a first aspect of the present application, an organic carbon element carbon monitoring system is provided, comprising a heating furnace, a detector and an optical channel, wherein a sampling filter is arranged in the optical channel, and the detector is arranged at the outlet of the optical channel; the organic carbon element carbon monitoring system comprises:

[0014] A first switching module, a quantitative pipeline, a second switching module, a third switching module and an output pipeline connected in sequence;

[0015] The first switching module is used to selectively connect the inlet of the quantitative pipeline to the standard solution supply pipeline or the carrier solution supply pipeline;

[0016] The second switching module is used to selectively connect the outlet of the quantitative pipeline to the waste liquid collection pipeline or the inlet of the third switching module;

[0017] The third switching module is used to selectively connect the inlet of the output pipeline to the gas supply pipeline or the outlet of the second switching module;

[0018] The outlet of the output pipeline extends into the branch pipe, and the branch pipe is connected with the optical channel through the first opening.

[0019] Optionally, it further includes: a first switch, which is located on the carrier liquid supply pipeline and is arranged between the carrier liquid storage container and the first switching module.

[0020] Optionally, it further includes: a first pump; the first pump is located on the standard solution supply pipeline and is arranged between the standard solution storage container and the first switching module.

[0021] Optionally, it further includes: a second pump; the second pump is located on the carrier liquid supply pipeline and is arranged between the carrier liquid storage container and the first switching module.

[0022] In a second aspect of the present application, a method for monitoring carbon in organic carbon is provided, including a calibration phase; the calibration phase includes the following steps:

[0023] S1: The first switching module selects to connect the standard solution supply pipeline, and the second switching module selects to connect the waste liquid collection pipeline; the standard solution enters the quantitative module through the first switching module until the set solution volume is reached, and the excess solution enters the waste liquid collection pipeline;

[0024] S2: The first switching module selects to connect the carrier liquid providing pipeline, the second switching module selects to connect the inlet of the third switching module, and the third switching module selects to connect the outlet of the second switching module; the carrier liquid passes through the first switching module, pushes the standard solution in the quantitative module to pass through the second switching module and the third switching module in sequence, and enters the optical channel through the first opening;

[0025] S3: After the standard solution in the quantitative module is emptied, the third switching module selects a connected gas supply pipeline, and the inert gas enters the branch pipe through the third switching module;

[0026] S4: The monitoring system enters the analysis state, the detector outputs the detection result of the standard solution, and completes the calibration according to the theoretical value of the standard solution.

[0027] Optionally, before step S1, the method further includes:

[0028] S0: The third switching module selects a connecting gas supply pipeline, and the inert gas enters the branch pipe through the third switching module to purge the branch pipe.

[0029] Optionally, the detector is a multi-channel detector, which is used to measure n types of gases and obtain measurement signals of the n types of gases; the method further includes:

[0030] The concentrations are x i n types of standard gases are introduced into the heating furnace at different times, and the detectors of m channels output signals A corresponding to the n types of standard gases at different times. ij , the i-th channel and the concentration are x i The type of standard gas corresponds to i = 1, 2 ... n, j = 1, 2 ... m, n = m;

[0031] Get the coefficient k i =xi / A ii , get the matrix

[0032] In step S4, the m channels of the detector output signals B respectively. j , j = 1, 2…m;

[0033] Get the matrix

[0034] Get the concentration of the gas in the standard liquid corresponding to the i-th channel of the detector: C i =k i ·a ii .

[0035] Optionally, n=m=2, and the standard gas includes carbon dioxide and water vapor.

[0036] Optionally, a time period is set, the time period includes multiple cycles, and each cycle is divided into d time sub-segments t i , adjacent time sub-segments are separated by a period, and d is an integer;

[0037] In the set time period, obtain the same time sub-segment t i The corresponding minimum value f of the ratio of organic carbon concentration to elemental carbon concentration i , i=1,2…d;

[0038] Determine all the minimum values ​​f corresponding to the same time segment i Is it less than the threshold?

[0039] If the result is yes, the time subsegment A where the current time is located i The primary organic carbon concentration C POC ≈f i ·C EC , secondary organic carbon concentration C SOC ≈C OC -f i ·C EC ,C OC , C EC They are respectively the organic carbon concentration and elemental carbon concentration of the time subsegment of the current time;

[0040] If the result is no, increase the set time period until all minimum values ​​f corresponding to the same time sub-segment are i are all less than the threshold.

[0041] Compared with the prior art, this application has the following beneficial effects:

[0042] (1) Good calibration repeatability and small error;

[0043] The present application can automatically apply the standard liquid without opening the heating furnace, and does not need to dismantle the quartz furnace, thereby ensuring air tightness, and the internal standard liquid receiving area will not be exposed to ambient air, thereby eliminating the influence of VOCs in the air; the outside world uses the first opening to automatically apply the standard liquid into the optical channel, without manual operation, avoiding the influence of human operation, and has an automatic titration calibration function with good repeatability;

[0044] (2) By introducing various standard gases (including carbon dioxide) into the heating furnace, coefficients and matrices are obtained, eliminating the interference of water on carbon dioxide measurement and reducing the error.

[0045] (3) The estimation of primary organic carbon concentration and secondary organic carbon concentration was realized;

[0046] (4) By setting time periods, cycles, and divided time sub-segments, as well as thresholds and judgments, the primary organic carbon concentration and secondary organic carbon concentration at the current time are scientifically estimated to achieve online real-time data analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of this specification. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0048] Figure 1 It is a structural block diagram of the organic carbon element carbon monitoring system according to an embodiment of the present invention;

[0049] Figure 2 A schematic diagram of the specific structure of the organic carbon element carbon monitoring system provided in this application;

[0050] Figure 3 Schematic diagram of the heating furnace of the organic carbon element carbon monitoring system provided in this application. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. It should be noted that, in the absence of conflict, the embodiments in the present disclosure and the features in the embodiments can be combined, separated, interchanged and / or rearranged with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0052] The terms used here are for the purpose of describing specific embodiments, and are not intended to be restrictive. As used here, unless the context clearly indicates otherwise, the singular forms "one (kind, person)" and "said (the)" are also intended to include plural forms. In addition, when the terms "comprise" and / or "include" and their variations are used in this specification, it is explained that there are stated features, integral bodies, steps, operations, parts, assemblies and / or their groups, but it is not excluded that there are or add one or more other features, integral bodies, steps, operations, parts, assemblies and / or their groups. It should also be noted that, as used here, the terms "substantially", "approximately" and other similar terms are used as approximate terms and not as degree terms, so that they are used to explain the inherent deviations of the measured values, calculated values ​​and / or the values ​​provided that will be recognized by those of ordinary skill in the art.

[0053] Figure 1 as well as Figure 2 The structural block diagram and specific structural schematic diagram of the organic carbon element carbon monitoring system of the embodiment of the present invention are respectively given, such as Figure 1 as well as Figure 2 As shown, the organic carbon element carbon monitoring system includes an optical channel 1, a sampling filter membrane 51 is arranged in the optical channel 1, and a detector (not shown in the figure) is arranged at the outlet of the optical channel 1.

[0054] The organic carbon element carbon monitoring system involved in the present application enriches particulate matter on a high temperature resistant quartz filter membrane in a heating furnace through automatic sampling. The laser beam emitted by the laser is incident on the sampling filter membrane through the optical channel in the heating furnace. After being absorbed and scattered by the filter membrane and the particulate matter thereon, it is received by the detector, and the detector performs subsequent sample analysis based on the received signal. The control system is used to coordinate the mutual cooperation between the various parts in the organic carbon element carbon monitoring system, complete sample analysis, and realize functions such as human-computer interaction and data communication with the host computer. The data processing unit is used to collect data, perform calculations and output results. It can be understood that the improvements of the present application are mainly aimed at the automatic titration device in the organic carbon element carbon monitoring system. Other parts of the organic carbon element carbon monitoring system can refer to the contents of the prior art and will not be repeated here.

[0055] The organic carbon element carbon monitoring system includes: a first switching module 31, a quantitative pipeline 81, a second switching module 32, a third switching module 33 and an output pipeline 411 which are connected in sequence.

[0056] The first switching module 31 is used to selectively connect the inlet of the quantitative pipeline 81 to the standard solution supply pipeline or the carrier liquid supply pipeline. The standard solution supply pipeline is provided with a standard solution storage container 11 and a first pump 21. The carrier liquid supply pipeline is provided with a carrier liquid storage container 12 and a second pump 22.

[0057] The second switching module 32 is used to selectively connect the outlet of the quantitative pipeline 81 to the waste liquid collection pipeline or the inlet of the third switching module 33. A waste liquid storage container 14 is provided at the outlet of the waste liquid collection pipeline.

[0058] The third switching module 33 is used to selectively connect the inlet of the output pipeline 411 to the gas supply pipeline or the outlet of the second switching module 32. A gas storage container 13 is provided at the inlet of the gas supply pipeline.

[0059] The outlet of the output pipeline 411 extends into the branch pipe 41 , and the branch pipe 41 is connected to the optical channel 1 through the first opening 100 .

[0060] In order to push the standard liquid and exhaust the oxygen in the heating furnace, further, the carrier liquid is ultrapure water, and the gas storage container 13 contains an inert gas. The standard solution can be a sucrose solution.

[0061] It can be understood that the branch pipe 41 is fixed on the heating furnace, and the first opening 100 connects the branch pipe 41 and the heating furnace.

[0062] In addition, the organic carbon element carbon monitoring system provided in the present application further includes: a first switch 34 , which is located on the carrier liquid supply pipeline and is arranged between the carrier liquid storage container 12 and the first switching module 31 .

[0063] like Figure 2 As shown, the quartz heating furnace includes a straight optical channel 1, and a sampling filter membrane 51 is vertically arranged in the optical channel 1.

[0064] The upper side of the heating furnace has a first opening 100, and the branch pipe 41 is fixed on the vertical upper side of the first opening 100. The first opening 100 connects the branch pipe 41 and the optical channel 1. The output pipeline 411 is arranged in the branch pipe 41 and passes through the first opening 100. In the optical channel 1, a container 101 is arranged near the sampling filter membrane 51 to accommodate the standard solution dripped from the output pipeline 411.

[0065] The carbon dioxide standard gas and the water vapor standard gas are both connected to the branch pipe 41 through the first opening 100 .

[0066] The standard solution (sucrose solution) storage container 11 is connected to the first pump 21 and the first inlet of the first switching module 31 in sequence, and the carrier liquid (ultrapure water) storage container 12 is connected to the second pump 22, the third valve 34 and the second inlet of the first switching module 31 in sequence. The outlet of the first switching module 31 is connected to the quantitative module 81 (quantitative loop) and the inlet of the second switching module 32 in sequence. One outlet of the second switching module 32 is connected to the waste liquid storage container 14, and the other outlet is connected to the third switching module 33. Both the first switching module 31 and the second switching module 32 use electromagnetic three-way valves.

[0067] The third switching module 33 includes a first valve 331 and a second valve 332 , so that the gas (inert gas) storage container 13 and another outlet of the second switching module 32 (through the three-way valve 71 ) are selectively connected to the output pipeline 411 .

[0068] like Figure 3 As shown in the schematic diagram of the heating furnace of the organic carbon element carbon monitoring system provided in this application, Figure 3 At position 1 or position 2 shown in the figure, a container 101 for receiving the solution and a branch pipe 41 are provided, and the branch pipe 41 is used for automatically dropping the standard solution.

[0069] Specifically, a quartz branch tube 41 can be added at position 1 or position 2. The inner diameter of the quartz branch tube 41 is as thin as possible. The thin tube (output pipeline 411) at the lower end of the three-way structure can be inserted into the quartz branch tube 41 and sealed at the quartz branch tube opening.

[0070] Furthermore, if the thin tube (output pipe 411) inserted into the quartz branch pipe 41 is a pipe made of high-temperature resistant material, it can be inserted all the way to the bottom of the quartz branch pipe 41 and connected to the inside of the quartz furnace, but it cannot go deep into the quartz furnace because going deep into the quartz furnace may block the laser light path.

[0071] If the thin tube (output pipe 411) below the tee is not made of high temperature resistant material, the outlet can be extended into the quartz branch pipe 41 for a short distance, because the area near the pipe mouth of the quartz branch pipe belongs to the normal temperature area, and the lower part of the quartz pipe is close to the quartz furnace, and the analysis process will involve a high temperature process.

[0072] An organic carbon element carbon monitoring method according to an embodiment of the present invention is implemented on any one of the organic carbon element carbon monitoring systems described above, and the method includes a calibration phase; the calibration phase includes the following steps:

[0073] S1: The first switching module selects to connect the standard solution supply pipeline, and the second switching module selects to connect the waste liquid collection pipeline; the standard solution enters the quantitative module through the first switching module until the set solution volume is reached, and the excess solution enters the waste liquid collection pipeline.

[0074] S2: The first switching module selects a pipeline connected to the carrier liquid, the second switching module selects an inlet connected to the third switching module, and the third switching module selects an outlet connected to the second switching module; the carrier liquid passes through the first switching module, pushing the standard solution in the quantitative module to pass through the second switching module and the third switching module in turn, and enters the optical channel through the first opening.

[0075] S3: After the standard solution in the quantitative module is emptied, the third switching module selects a connected gas supply pipeline, and the inert gas enters the branch pipe through the third switching module.

[0076] S4: The monitoring system enters the analysis state, the detector outputs the detection result of the standard solution, and completes the calibration according to the theoretical value of the standard solution.

[0077] Furthermore, the detection method further comprises: executing step S0 before step S1: the third switching module selects a connecting gas supply pipeline, and the inert gas enters the branch pipe through the third switching module to purge the branch pipe.

[0078] The working process of the device provided by this application is specifically introduced below:

[0079] When the analyzer is working normally and no standard solution titration calibration is carried out, the second valve 332 is opened, and the high-purity inert gas enters the branch pipe through the second valve 332 to purge the branch pipe to prevent oxygen from remaining inside the branch pipe. At this time, the third valve 34 is closed, and the pump 21 of the standard solution (sucrose solution) supply pipeline may not work, and the standard solution in the quantitative ring 81 may be in an empty state. If the pump 21 of the standard solution (sucrose solution) supply pipeline works, the quantitative ring 81 is filled with the standard solution, and waste liquid is discharged into the waste liquid barrel 14 in real time. At this time, the ultrapure water pump does not work.

[0080] When the analyzer stops working and is ready to carry out standard solution titration calibration, the whole machine will go through the analysis process once or more times to clear the furnace to ensure that there is no residual oxygen in the pipeline and no residual pollutants on the sampling filter membrane. Then the second valve 332 is closed, and at the same time, the pump 21 of the pipeline providing the standard solution (sucrose solution) starts to fill the standard solution into the quantitative ring 81, and the excess solution is discharged into the waste liquid barrel 14.

[0081] After the quantitative ring 81 is filled with the standard solution, the pump 22 of the pipeline providing the carrier liquid (ultrapure water) starts working, and the third valve 34 opens. At this time, the ultrapure water will act as the carrier liquid to drive the standard solution in the quantitative ring 81 to flow into the three-way structure, further enter the capillary in the quartz branch pipe 41, and finally drip onto the quartz filter membrane at the lower wall of the quartz furnace or into the container.

[0082] When all the solution in the quantitative ring 81 is dripped into the quartz furnace, the pump 22 of the pipeline providing the carrier liquid (ultrapure water) stops working, so as to ensure that all standard liquids are brought into the quartz furnace. After the pump stops working, some ultrapure water may remain in the capillary tube. At this time, the second valve 332 is opened, and the high-purity inert gas begins to be purged, so that the liquid remaining in the capillary tube due to pressure problems can continue to be dripped into the quartz furnace.

[0083] The third valve 34 is closed, the second valve 332 remains open, and the whole machine starts the analysis process. During the analysis process, the carbon component in the standard solution will generate gas as the temperature changes, and will be further oxidized into CO2, which will eventually be measured by the detector to achieve automatic titration calibration of the standard solution of the whole machine.

[0084] Furthermore, if different carbon contents are to be measured, the quantitative loop can be filled multiple times and then brought into the quartz furnace. After reaching a specific number of times, that is, reaching a specific standard liquid volume, the analysis process can be carried out to achieve the measurement of standard solutions with different carbon contents. Alternatively, the measurement of different carbon contents can be achieved by changing the solution concentration in the standard liquid container.

[0085] In the above method, adding the standard solution will bring more water, which will become gaseous water during the subsequent heating and decomposition process, and finally enter the measurement module, causing interference to the CO2 measurement. In addition, during normal operation, the particulate matter enriched on the high-temperature resistant filter membrane has complex composition and will also produce a lot of interfering gases at high temperatures, which will interfere with the CO2 measurement.

[0086] In order to calibrate the detector to eliminate the interference of moisture on carbon dioxide measurement, the detection method further includes:

[0087] The detector is a multi-channel detector, which is used to measure n kinds of gases and obtain measurement signals of the n kinds of gases; the method also includes:

[0088] The concentrations are x i n types of standard gases are introduced into the heating furnace at different times, and the detectors of m channels output signals A corresponding to the n types of standard gases at different times. ij , the i-th channel and the concentration are x i The type of standard gas corresponds to i = 1, 2 ... n, j = 1, 2 ... m, n = m;

[0089] Get coefficient k i =x i / A ii , get the matrix

[0090] In step S4, the m channels of the detector output signals B respectively. j , j = 1, 2…m;

[0091] Get the matrix

[0092] Get the concentration of the gas in the standard liquid corresponding to the i-th channel of the detector: y i =k i ·a ii .

[0093] As a specific embodiment, the calibration method is specifically as follows: a dual-channel detector is selected, which can simultaneously measure CO2 and gaseous water signals, that is, n=m=2.

[0094] The carbon dioxide standard gas with a concentration x1 = 0.1% (volume percentage, the same below) enters the branch pipe 41, and the first channel (corresponding to carbon dioxide) of the two-channel detector outputs a signal A 11 =0.4761, the second channel output signal A 12 =0.

[0095] The water vapor standard gas with a concentration of x2 = 10% enters the branch pipe 41, and the first channel of the two-channel detector outputs a signal A 21 =0.0115, the second channel (corresponding to water vapor) output signal A 22 =0.3923; that is, two kinds of standard gases and two channels are used, n=m=2.

[0096] Obtain the coefficient k1=x1 / A corresponding to carbon dioxide 11 =0.002100399, the coefficient corresponding to water vapor k2 = x2 / A 22 =0.254906959.

[0097] Get the matrix Save the coefficients and matrix T.

[0098] Monitoring system calibration, including the following steps:

[0099] The second valve 332 is opened, and the inert gas enters the output pipeline 411 to ensure that there is no oxygen residue in the pipeline.

[0100] The second valve 332 and the third valve 34 are closed, and the first switching module 31 and the second switching module 32 are switched, so that the standard solution passes through the first pump 21, the first switching module 31, the quantitative module 81 and the second switching module 32 in sequence and enters the waste liquid container 14, thereby realizing the quantitative standard solution.

[0101] The first switching module 31 and the second switching module 32 are switched, the second valve 332 is closed, the first valve 331 is opened, the third valve 34 is opened, and the carrier liquid passes through the second pump 22, the third valve 34 and the first switching module 31 in sequence to push the standard liquid in the quantitative module 81. The standard liquid passes through the second switching module 32, the first valve 331, the three-way valve 71 and the output pipeline 411 in sequence, passes through the first opening into the optical channel 1 of the heating furnace, and drips into the container 101.

[0102] The second valve 332 is opened, and the inert gas passes through the second valve 332 and the three-way valve 71 in sequence and is output into the output pipeline 411 , so that the residual liquid (including ultrapure water) in the output pipeline 411 drips into the optical channel 1 .

[0103] The monitoring system enters the analysis state, and the two channels of the detector output signals B1=0.057 and B2=0.0123 respectively at a certain moment.

[0104] Get the matrix

[0105] Obtain the carbon dioxide concentration C1=k1·a in the standard liquid corresponding to the first channel at this moment 11 =0.011888%, and the water concentration corresponding to the second channel is C2=k2·a 22 =0.313536%.

[0106] The calibration is completed by using the ratio of the integral value of the above-corrected carbon dioxide concentration at all times obtained in the anaerobic and aerobic stages of the analysis state to the integral value of the internal standard carbon dioxide concentration as a signal, combined with the theoretical value of the carbon content in the standard solution.

[0107] In order to scientifically estimate the primary organic carbon concentration and secondary organic carbon concentration at the current time, a time period is further set, and the time period includes multiple cycles, and each cycle is divided into d time sub-segments t i , adjacent time sub-segments are separated by a period, and d is an integer;

[0108] In the set time period, obtain the same time sub-segment t i The corresponding minimum value f of the ratio of organic carbon concentration to elemental carbon concentration i , i=1,2…d;

[0109] Determine all the minimum values ​​f corresponding to the same time segment i Is it less than the threshold?

[0110] If the result is yes, the time subsegment A where the current time is located i The primary organic carbon concentration C POC ≈f i ·C EC, secondary organic carbon concentration C SOC ≈C OC -f i ·C EC ,C OC , C EC They are respectively the organic carbon concentration and elemental carbon concentration of the time subsegment of the current time;

[0111] If the result is no, increase the set time period until all minimum values ​​f corresponding to the same time sub-segment are i are all less than the threshold.

[0112] Specifically, after calibration, the instrument should carry out normal online monitoring work, through automatic sampling, the particulate matter is enriched on the filter membrane, and then through anaerobic and aerobic thermal desorption processes, the organic carbon OC and elemental carbon EC concentrations in the particulate matter are obtained. After obtaining the concentration, data analysis can be carried out according to the following implementation steps:

[0113] Set the time period to 7 days, and the normal sampling and analysis time of the monitoring system is 1 hour. If the equipment is uninterrupted, there are 168 sampling and analysis processes in 7 days. If the equipment is powered off or maintained, the sampling and analysis process in 7 days is less than 168 times. Suppose the number of sampling and analysis in 7 days is n, then n≤168;

[0114] Step 1: The system automatically calculates the organic carbon concentration value C for seven days before the current time point, that is, n hours, based on the time point OC and elemental carbon concentration C EC The ratio C OC / C EC , and automatically find the minimum value among n ratios (C OC / C EC ) min ;

[0115] Step 2: If (C OC / C EC ) min <2, then the concentration of organic carbon POC in the current cycle is C POC ≈C EC *(C OC / C EC ) min At this time, the secondary organic carbon SOC concentration C SOC ≈C OC -C POC , the system automatically gives the estimated concentrations of primary organic carbon POC and secondary organic carbon SOC;

[0116] Step 3: If (C OC / C EC ) min≥2, the system continues to calculate the (C OC / C EC ) min , where j = 1, 2, 3 ..., until (C OC / C EC ) min <2, stop the calculation and calculate the POC and SOC concentrations according to step 2. The system automatically gives the estimated concentrations of primary organic carbon POC and secondary organic carbon SOC.

[0117] Furthermore, more detailed divisions can be made according to different times of the day, for example:

[0118] The time period can be set to 7 days, 7 cycles, each cycle is 1 day, and each day is divided into 5 time sub-segments, that is, d=5, specifically:

[0119] t1: 0:00~6:00; the interval between the time sub-segments t1 of two consecutive days is 1 day, the same below

[0120] t2: 6:00-9:00 (morning rush hour);

[0121] t3: 9:00 to 17:00;

[0122] t4: 17:00~21:00 (evening peak);

[0123] t5:21:00~0:00.

[0124] During the set time period (i.e. the first 7 days), t i The minimum value of the ratio of organic carbon concentration to elemental carbon concentration in i , i=1,2…d.

[0125] For example, if there are 7 identical time segments t2 in 7 days, we obtain 3 ratios corresponding to t2 on each day (1 ratio per hour), a total of 21 ratios, and then obtain the minimum value f2 of the ratio. Similarly, we obtain f1, f3, f4 and f5.

[0126] Determine all the minimum values ​​f corresponding to the same time segment i (d time sub-segments, corresponding to d minimum values) are all less than the threshold, the threshold is 2;

[0127] If the result is yes, the time subsegment A where the current time is located i The primary organic carbon concentration C POC ≈f i ·C EC , secondary organic carbon concentration C SOC ≈C OC -f i ·CEC ,C OC , C EC They are respectively the organic carbon concentration and elemental carbon concentration of the latest sampling and analysis process in the time subsegment of the current time.

[0128] If the current time is 8:00, in the time sub-segment t1, the primary organic carbon concentration C POC ≈f1·C EC , secondary organic carbon concentration C SOC ≈C OC -f1·C EC .

[0129] The current time is 19:00, in time segment t3, the primary organic carbon concentration C POC ≈f3·C EC , secondary organic carbon concentration C SOC ≈C OC -f3·C EC .

[0130] If the result is no, increase the set time period, such as the first 8 days, until all the minimum values ​​f corresponding to the same time sub-segment are i are all less than the threshold.

[0131] It is understandable that a blank filter membrane may be provided in the optical channel 1 so that the standard solution is titrated on the blank filter membrane. A multi-way valve may also be used to replace the three switching modules, which does not affect the implementation of the present application.

[0132] The present application sets a titration branch in the heating area of ​​the quartz furnace, and the branch is externally connected to the standard solution titration flow path. The entire flow path can be controlled by the system control unit to achieve fully automatic titration calibration.

[0133] The specific algorithm provided in the present application solves the problem of interference caused by gaseous water during the process of adding the solution.

[0134] The quartz branch provided in this application can also be used to connect standard gas for standard gas calibration.

[0135] In addition, the system provided in the present application can perform data analysis based on the measured organic carbon and elemental carbon concentrations to obtain estimated concentrations of primary organic carbon and secondary organic carbon.

[0136] The specific implementation methods described above further illustrate the purpose, technical solutions and beneficial effects of the present application in detail. It should be understood that the above description is only the specific implementation method of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. An organic carbon element carbon monitoring system, comprising a heating furnace, a detector and an optical channel, wherein a sampling filter is arranged in the optical channel, and the detector is arranged at the outlet of the optical channel; characterized in that: The organic carbon element carbon monitoring system comprises: A first switching module, a quantitative pipeline, a second switching module, a third switching module and an output pipeline connected in sequence; The first switching module is used to selectively connect the inlet of the quantitative pipeline to the standard solution supply pipeline or the carrier solution supply pipeline; The second switching module is used to selectively connect the outlet of the quantitative pipeline to the waste liquid collection pipeline or the inlet of the third switching module; The third switching module is used to selectively connect the inlet of the output pipeline to the gas supply pipeline or the outlet of the second switching module; The outlet of the output pipeline extends into the branch pipe, and the branch pipe is connected with the optical channel through the first opening.

2. The organic carbon element carbon monitoring system according to claim 1, characterized in that: Also includes: The first switch is located on the carrier liquid supply pipeline and is arranged between the carrier liquid storage container and the first switching module.

3. The organic carbon element carbon monitoring system according to claim 2, characterized in that: Also includes: The first pump is located on the standard solution supply pipeline and is arranged between the standard solution storage container and the first switching module.

4. The organic carbon element carbon monitoring system according to claim 2, characterized in that: Also includes: Second pump; The second pump is located on the carrier liquid supply pipeline and is arranged between the carrier liquid storage container and the first switching module.

5. A method for monitoring organic carbon, comprising a calibration phase; characterized in that: The calibration phase includes the following steps: S1: The first switching module selects to connect the standard solution supply pipeline, and the second switching module selects to connect the waste liquid collection pipeline; the standard solution enters the quantitative module through the first switching module until the set solution volume is reached, and the excess solution enters the waste liquid collection pipeline; S2: The first switching module selects to connect the carrier liquid providing pipeline, the second switching module selects to connect the inlet of the third switching module, and the third switching module selects to connect the outlet of the second switching module; the carrier liquid passes through the first switching module, pushes the standard solution in the quantitative module to pass through the second switching module and the third switching module in sequence, and enters the optical channel through the first opening; S3: After the standard solution in the quantitative module is emptied, the third switching module selects a connected gas supply pipeline, and the inert gas enters the branch pipe through the third switching module; S4: The monitoring system enters the analysis state, the detector outputs the detection result of the standard solution, and completes the calibration according to the theoretical value of the standard solution.

6. The method for monitoring organic carbon according to claim 5, characterized in that: Before step S1, the method further includes: S0: The third switching module selects a connecting gas supply pipeline, and the inert gas enters the branch pipe through the third switching module to purge the branch pipe.

7. The method for monitoring organic carbon according to claim 5, characterized in that: The detector is a multi-channel detector, which is used to measure n kinds of gases and obtain measurement signals of the n kinds of gases; the method also includes: The concentrations are x i n types of standard gases are introduced into the heating furnace at different times, and the detectors of m channels output signals A corresponding to the n types of standard gases at different times. ij , the i-th channel and the concentration are x i Corresponding to the type of standard gas, i=1,2…n, j=1,2…m, n=m; Get the coefficient k i =x i / A ii , we get the matrix T = ; In step S4, the m channels of the detector output signals B respectively. j , j = 1, 2…m; Get the matrix ; Get the concentration of the gas in the standard liquid corresponding to the i-th channel of the detector: .

8. The method for monitoring organic carbon according to claim 7, characterized in that: n=m=2, and the standard gas includes carbon dioxide and water vapor.

9. The method for monitoring organic carbon according to claim 8, characterized in that: Set the time period, which includes multiple cycles, and divide each cycle into d time sub-segments t i , adjacent time sub-segments are separated by a period, and d is an integer; In the set time period, obtain the same time sub-segment t i The corresponding minimum value f of the ratio of organic carbon concentration to elemental carbon concentration i , i=1,2…d; Determine all the minimum values ​​f corresponding to the same time segment i Is it less than the threshold? If the result is yes, the time subsegment A where the current time is located i The primary organic carbon concentration C POC ≈f i ·C EC , secondary organic carbon concentration C SOC ≈C OC -f i ·C EC , C OC , C EC They are respectively the organic carbon concentration and elemental carbon concentration of the time subsegment of the current time; If the result is no, increase the set time period until all minimum values ​​f corresponding to the same time sub-segment are i are all less than the threshold.

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