Organic carbon element carbon monitoring system and method

Abstract

The application 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 sequentially connected. The first switching module is used for selectively connecting a standard solution providing pipeline or a carrier liquid providing pipeline to an inlet of the quantitative pipeline. The second switching module is used for selectively connecting a waste liquid collecting pipeline or an inlet of the third switching module to an outlet of the quantitative pipeline. The third switching module is used for selectively connecting a gas providing pipeline or an outlet of the second switching module to an inlet of the output pipeline. An outlet of the output pipeline extends into a branch pipe, and the branch pipe is connected with the optical channel through a first opening. The application avoids the influence of manual operation, has the automatic titration calibration function, and is good in repeatability. In addition, the application eliminates the interference of water on the measurement of carbon dioxide, and reduces the error.

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] Carbonaceous components in aerosols, classified by chemical composition, primarily include organic carbon (OC), elemental carbon (EC), and a small amount of carbonate carbon (CC). OC comprises various organic compounds and originates from primary emissions and secondary conversion. EC is elemental carbon, primarily derived from incomplete combustion of fuels. Total carbon (TC) can be roughly considered the sum of OC and EC. Black carbon (BC) is a carbonaceous component with strong light-absorbing properties.

[0003] There are three main types of carbonaceous aerosol analysis methods: 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, which roughly assumes that the absorption of light by other components of the particulate matter is negligible relative to the light absorption of EC. Its 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 accurately determines the dividing point of OC and EC based on the change of laser intensity on the filter membrane during thermal decomposition. It is currently the most widely used and recognized mature carbonaceous aerosol analysis method in the world.

[0007] Most current thermo-optical organic carbon elemental carbon analyzers are based on thermal-optical calibration combined with 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 automatically collects particulate matter on a high-temperature quartz filter within a heating furnace through sampling. The pipeline is then purged with pure He gas, and the anaerobic and aerobic thermal desorption processes are sequentially initiated. The resulting gas is converted to CO2 in a high-temperature oxidation furnace (conversion channel) and then enters the NDIR analysis module. During the thermal desorption process, the split point between OC and EC can be determined based on changes in laser intensity. After thermal desorption, a He / CH4 internal standard gas passes through a quantitative loop and enters the pipeline. It is oxidized to CO2 in the oxidation furnace and then enters the NDIR. The OC and EC concentrations are calculated based on the ratio of the CO2 peak area before and after the split point to the internal standard peak area.

[0008] At present, the titration and calibration of standard solutions for online monitoring products of elemental carbon using the thermo-optical method mainly rely on manual operation. 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 is affected by differences in operating techniques of different people, and sometimes introduces 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 purpose of the present invention is achieved through the following technical solutions:

[0013] In a first aspect of the present application, a carbon monitoring system for organic carbon is provided, comprising a heating furnace, a detector, and an optical channel, wherein a sampling filter is disposed in the optical channel and the detector is disposed at the outlet of the optical channel; the carbon monitoring system for organic carbon 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 communicated 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 elemental carbon in organic carbon is provided, comprising a calibration phase; the calibration phase comprises 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 to the carrier liquid supply pipeline, the second switching module selects to connect to the inlet of the third switching module, and the third switching module selects to connect to the outlet of the second switching module; the carrier liquid passes through the first switching module, pushing the standard solution in the quantitative module 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 the 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 the 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 for measuring n types of gases and obtaining 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 coefficient k i =xi / A ii , obtain a matrix

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

[0033] Obtain a matrix

[0034] Obtain the concentration of the gas corresponding to the i th channel of the detector in the standard liquid: 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 d time sub-periods t i are divided in each cycle, adjacent time sub-periods are separated by one cycle, and d is an integer.

[0037] In the set time period, the minimum value f i of the ratio of the organic carbon concentration and the elemental carbon concentration corresponding to the same time sub-period t i is obtained, i = 1, 2…d.

[0038] It is determined whether all the minimum values f i corresponding to the same time sub-period are less than a threshold value.

[0039] If the result is yes, the primary organic carbon concentration C i of the time sub-period A POC in which the current time is located is C i · C EC , the secondary organic carbon concentration C SOC is C OC - f i · C EC , C OC and C EC are the organic carbon concentration and the elemental carbon concentration of the time sub-period in which the current time is located respectively.

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

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

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

[0043] The present invention can automatically apply the standard liquid without opening the heating furnace and dismantling the quartz furnace, thereby ensuring airtightness. The internal standard liquid receiving area will not be exposed to ambient air, thereby eliminating the influence of VOCs in the air. The standard liquid is automatically applied to the optical channel from the outside through the first opening, without manual operation, avoiding the influence of human operation, and having an automatic titration calibration function with good repeatability.

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

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

[0046] (4) By using the set time period, cycle 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 This is a structural block diagram of an 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 solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction 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 this disclosure and the features in the embodiments can be combined, separated, interchanged and / or rearranged with each other. Based on the embodiments in this 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 herein are for the purpose of describing specific embodiments and are not intended to be restrictive. As used herein, 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, the features, integral bodies, steps, operations, parts, assemblies and / or their groups stated are explained, but the presence or addition of one or more other features, integral bodies, steps, operations, parts, assemblies and / or their groups is not excluded. It should also be noted that, as used herein, 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 diagram of the organic carbon element carbon monitoring system according to the embodiment of the present invention are respectively given. Figure 1 as well as Figure 2 As shown, the organic carbon element carbon monitoring system includes an optical channel 1, a sampling filter 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 this application is a system that 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 this 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 equipped with a standard solution storage container 11 and a first pump 21. The carrier liquid supply pipeline is equipped 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 pipe 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, the carrier liquid is ultrapure water and the gas storage container 13 contains 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 cylindrical 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. A branch pipe 41 is fixed vertically above this opening 100, connecting the branch pipe 41 with the optical channel 1. An output pipe 411 is disposed within the branch pipe 41 and passes through the first opening 100. A container 101 is provided within the optical channel 1 near the sampling filter 51 to accommodate the standard solution dripped from the output pipe 411.

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

[0066] The standard solution (sucrose solution) storage container 11 is sequentially connected to the first pump 21 and the first inlet of the first switching module 31. The carrier liquid (ultrapure water) storage container 12 is sequentially connected to the second pump 22, the third valve 34, and the second inlet of the first switching module 31. The outlet of the first switching module 31 is sequentially connected to the quantitative module 81 (quantitative loop) and the inlet of the second switching module 32. 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 other outlet of the gas (inert gas) storage container 13 and the second switching module 32 (through the T-joint 71 ) is 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. 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 at the lower end of the three-way structure (output pipeline 411) 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 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 below the tee (output pipe 411) is not made of high-temperature resistant material, the outlet can be extended a short distance into the quartz branch pipe 41. This is because the area near the pipe mouth of the quartz branch pipe is in the normal temperature area, and the lower part of the quartz pipe is close to the quartz furnace, so the analysis process will involve high temperature.

[0072] An organic carbon element carbon monitoring method according to an embodiment of the present invention is implemented on any of the organic carbon element carbon monitoring systems described above, and 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 to connect to the carrier liquid providing pipeline, the second switching module selects to connect to the inlet of the third switching module, and the third switching module selects to connect to the outlet of the second switching module; the carrier liquid passes through the first switching module, pushing the standard solution in the quantitative module 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 the connecting 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 includes: executing step S0 before step S1: the third switching module selects a connected 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 described in detail below:

[0079] When the analyzer is operating normally and no standard solution titration calibration is being performed, the second valve 332 is opened, and high-purity inert gas enters the branch pipe through the second valve 332 to purge the branch pipe and prevent oxygen from accumulating inside the branch pipe. At this time, the third valve 34 is closed, and the pump 21 of the standard solution (sucrose solution) supply line can be inoperative, and the standard solution in the quantitative loop 81 can be emptied. If the pump 21 of the standard solution (sucrose solution) supply line is inoperative, the quantitative loop 81 is filled with standard solution, and waste liquid is discharged into the waste liquid barrel 14 in real time. At this time, the ultrapure water pump is inoperative.

[0080] When the analyzer stops working and is ready to carry out standard solution titration calibration, the entire machine will first go through the analysis process once or multiple times to clear the furnace to ensure that there is no oxygen residue in the pipeline and no contaminants remain on the sampling filter membrane. Then the second valve 332 is closed, and at the same time, the pump 21 of the standard solution (sucrose solution) supply pipeline 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 carrier liquid (ultrapure water) supply pipeline starts working, and the third valve 34 is opened. 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 into the thin tube in the quartz branch 41, and finally drip onto the quartz filter membrane at the lower wall of the quartz furnace or into the container.

[0082] When the solution in the quantitative ring 81 is all dropped into the quartz furnace, the pump 22 of the carrier liquid (ultra-pure water) supply pipeline stops working, so as to ensure that all the standard liquid is brought into the quartz furnace. After the pump stops working, some ultra-pure water may be left in the fine tube. At this time, the second valve 332 is opened, and the high-purity inert gas starts to purge, so as to continue to drop the liquid left in the fine tube due to pressure problems into the quartz furnace.

[0083] The third valve 34 is closed, and the second valve 332 remains open. The whole machine starts the analysis process. In the analysis process, the carbon component in the standard solution generates gas with the change of temperature, is further oxidized into CO2, and is finally measured by the detector to realize the automatic titration calibration of the whole machine standard solution.

[0084] Further, if different carbon amounts are to be measured, the quantitative ring can be filled multiple times and brought into the quartz furnace to achieve a specific number of times, that is, a specific amount of standard liquid, and then the analysis process is carried out, so as to realize the measurement of standard solutions with different carbon amounts. Alternatively, different carbon amounts can also be measured by changing the concentration of the solution in the standard liquid container.

[0085] The above method brings a lot of water when the standard solution is added. These water will become gaseous water in the subsequent heating and decomposition process, and finally enter the measurement module, which will interfere with the measurement of CO2. 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 interference gas at high temperature, which will interfere with the measurement of CO2.

[0086] In order to calibrate the detector to exclude the interference of water on the measurement of carbon dioxide, further, the detection method further comprises:

[0087] The detector is a multi-channel detector for measuring n kinds of gases to obtain measurement signals of the n kinds of gases; the method further comprises:

[0088] The concentration of n categories of standard gases is x i respectively, and the n categories of standard gases are introduced into the heating furnace in time, and the m-channel detector outputs signals A ij corresponding to the category of the standard gas with the concentration of x i , i=1, 2…n, j=1, 2…m, n=m.

[0089] The coefficient k i =x i / A ii is obtained, and the matrix

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

[0091] Get the matrix

[0092] Get the concentration of the gas corresponding to the i-th channel of the detector in the standard liquid: 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 of x1 = 0.1% (volume percentage, the same below) enters the branch pipe 41, and the first channel of the two-channel detector (corresponding to carbon dioxide) 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) outputs 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 remaining in the pipeline.

[0100] Close the second valve 332 and the third valve 34, and switch the first switching module 31 and the second switching module 32, 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 determination of the 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, and the third valve 34 is opened. The carrier liquid passes through the second pump 22, the third valve 34 and the first switching module 31 in sequence, pushing 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 tee 71 in sequence and outputs 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 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 obtained at all times 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. The time period includes multiple cycles, and each cycle is divided into d time sub-segments t i , adjacent sub-segments of the same time are separated by a period, and d is an integer;

[0108] During the set time period, the same time sub-segment t is obtained. 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 sub-segment 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 are the organic carbon concentration and elemental carbon concentration of the time subsegment at the current time;

[0111] If the answer is no, increase the set time period until all the minimum values ​​f corresponding to the same time sub-segment are equal. 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 the concentrations are obtained, the data analysis can be carried out according to the following implementation steps:

[0113] Set the time period to 7 days, and the monitoring system normally takes 1 hour to sample and analyze. If the equipment is uninterrupted, there will be a total of 168 sampling and analysis processes in 7 days. If the equipment is powered off or maintained, the sampling and analysis process in 7 days will be less than 168 times. Let the number of sampling and analysis times in 7 days be n, then n≤168;

[0114] Step 1: The system automatically calculates the organic carbon concentration C seven days before the current time point, that is, n hours ago. 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 (C OC / C EC ) min where j = 1, 2, 3, …, until (C OC / C EC ) min < 2, stop continuing to calculate, calculate POC and SOC concentrations according to step 2, and the system automatically gives the estimated concentrations of primary organic carbon POC and secondary organic carbon SOC.

[0117] Further, more detailed division can also 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 being 1 day, and 5 time sub-periods are divided in each 1 day, i.e. d = 5, specifically:

[0119] t1: 0:00-6:00; the time sub-period t1 of adjacent 2 days is separated by 1 day, and the same applies below

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

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

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

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

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

[0125] For example, there are 7 time sub-periods t2 in 7 days, 3 ratios (1 ratio per hour) corresponding to each 1-day t2 are obtained, a total of 21 ratios, and then the minimum value f2 of the ratios is obtained. Similarly, f1, f3, f4 and f5 are obtained.

[0126] Determine whether all the minimum values f i corresponding to the same time sub-period (d time sub-periods, corresponding to d minimum values) are less than the threshold value, which is 2;

[0127] If the result is yes, the primary organic carbon concentration C i of the time sub-period A POC wherein the current time is located is approximately f i · C EC , and the secondary organic carbon concentration C SOC is approximately 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 sub-segment 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 the 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 answer 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 can be provided in the optical channel 1 so that the standard solution is titrated on the blank filter membrane. A multi-way valve can 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 this application solves the problem of interference caused by gaseous water during the solution addition process.

[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 this application. It should be understood that the above description is only the specific implementation methods of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application should be included in the scope of protection of this application.

Claims

1. A method for monitoring carbon in organic carbon, applied to an organic carbon monitoring system, comprising a calibration phase; characterized in that: The organic carbon element carbon monitoring system includes a heating furnace, a detector and an optical channel, a sampling filter is arranged in the optical channel, and the detector is arranged at the outlet of the optical channel; the detector is a multi-channel detector for measuring n types of gases and obtaining measurement signals of n types of gases; The organic carbon element carbon monitoring system includes: 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 to the optical channel through the first opening; 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 to the carrier liquid supply pipeline, the second switching module selects to connect to the inlet of the third switching module, and the third switching module selects to connect to the outlet of the second switching module; the carrier liquid passes through the first switching module, pushing the standard solution in the quantitative module 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 the 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; S5: 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; Get coefficient k i =x i / A ii , get the matrix T= ; In step S4, the m channels of the detector respectively output signals B j , j=1,2…m; Get the matrix ; Get the concentration of the gas corresponding to the i-th channel of the detector in the standard liquid: .

2. The organic carbon element carbon monitoring system according to claim 1, characterized in that: The organic carbon element carbon monitoring system 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.

3. The method for monitoring organic carbon according to claim 2, wherein: The organic carbon element carbon monitoring system 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.

4. The method for monitoring organic carbon according to claim 2, wherein: The organic carbon element carbon monitoring system 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.

5. The method for monitoring organic carbon according to claim 1, wherein: Before step S1, the method further includes: S0: The third switching module selects the connecting gas supply pipeline, and the inert gas enters the branch pipe through the third switching module to purge the branch pipe.

6. The method for monitoring organic carbon according to claim 1, wherein: n=m=2, and the standard gas includes carbon dioxide and water vapor.

7. The method for monitoring organic carbon according to claim 6, characterized in that: Set the time period, which includes multiple cycles, and divide each cycle into d time sub-segments t i , adjacent sub-segments of the same time are separated by a period, and d is an integer; During the set time period, the same time sub-segment t is obtained. 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 sub-segment 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 are the organic carbon concentration and elemental carbon concentration of the time subsegment at the current time; If the answer is no, increase the set time period until all the minimum values ​​f corresponding to the same time sub-segment are equal. i are all less than the threshold.

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