Organic Carbon Element Carbon Analyzer

Abstract

The present invention discloses an organic carbon element carbon analyzer, comprising a decomposition furnace, a decomposition pipeline, an oxidation furnace and a detector, wherein the decomposition furnace comprises a decomposition furnace tube and a filter membrane arranged in the decomposition furnace tube, and a decomposition furnace heating device arranged on the decomposition furnace tube and used for heating the filter membrane, the decomposition pipeline is connected with the decomposition furnace tube, the oxidation furnace is arranged around the outer circumference of the decomposition pipeline and is provided with an air inlet and an air outlet at two opposite ends, the oxidation furnace is connected with the decomposition pipeline through the air inlet, and the detector is connected with the air outlet. In the organic carbon element carbon analyzer provided by the embodiment of the present invention, the oxidation furnace is arranged around the outer circumference of the decomposition pipeline, so that the entire gas path between the decomposition furnace and the oxidation furnace is in a high temperature state, which weakens the adsorption capacity of the decomposition pipeline to the decomposition gas, reduces sample loss, and improves the accuracy of the detection result.

Description

Technical Field

[0001] The present invention relates to the technical field of air quality detection, and in particular to an organic carbon element carbon analyzer. Background Art

[0002] In recent years, with the continuous development of global social economy and the continuous expansion of urban scale, air quality problems have become increasingly serious. The detection of organic carbon and elemental carbon content in the air is of great significance to the study of atmospheric chemical reactions and source analysis of pollutants, and has become a hot topic in the field of environmental monitoring today.

[0003] The organic carbon elemental carbon analyzer is mainly composed of a desorption furnace and an oxidation furnace. The working principle is to collect a certain volume of ambient air and blow it into the desorption furnace. The filter membrane in the desorption furnace is filtered and collects particulate matter in the air. Then, an oxygen-free carrier gas is introduced into the desorption furnace to place the filter membrane in an oxygen-free environment. At this time, the temperature of the desorption furnace is gradually increased to thermally decompose the organic carbon on the surface of the filter membrane and escape to enter the oxidation furnace for oxidation and conversion into carbon dioxide. Then, an aerobic carrier gas is introduced into the desorption furnace to place the filter membrane in an aerobic environment. The temperature of the desorption furnace is continued to be gradually increased to thermally decompose the elemental carbon in the filter membrane and escape to enter the oxidation furnace for oxidation and conversion into carbon dioxide. The carbon dioxide concentration output by the oxidation furnace is detected by a carbon dioxide detector to calculate the content of organic carbon and elemental carbon, or the generated carbon dioxide is converted into methane by a methane conversion furnace and then entered into a methane detector for detection. The content of organic carbon and elemental carbon is calculated by detecting the concentration of methane.

[0004] However, since the decomposition furnace and the oxidation furnace are set up independently of each other, the two need to be connected by a gas pipeline. The gas decomposed by heating in the decomposition furnace needs to pass through the gas pipeline and then enter the oxidation furnace, resulting in a low-temperature area between the decomposition furnace and the oxidation furnace. Organic carbon and elemental carbon are prone to adsorption losses in the low-temperature gas pipeline, affecting the accuracy of the final test results. Summary of the invention

[0005] The present invention provides an organic carbon elemental carbon analyzer to solve the technical problems that the existing analysis furnace and oxidation furnace are independently arranged, there is a low temperature zone so that the organic carbon / elemental carbon is adsorbed in the pipeline, thereby making the accuracy of organic carbon / elemental carbon detection low and the instrument volume large.

[0006] According to one aspect of the present invention, there is provided an organic carbon element carbon analyzer, comprising a decomposition furnace, a decomposition pipeline, an oxidation furnace and a detector, wherein the decomposition furnace comprises a decomposition furnace tube and a filter membrane arranged in the decomposition furnace tube, and a decomposition furnace heating device arranged on the decomposition furnace tube and used for heating the filter membrane, the decomposition pipeline is connected to the decomposition furnace tube, the oxidation furnace is arranged around the periphery of the decomposition pipeline and is provided with an air inlet and an air outlet at opposite ends, the oxidation furnace is connected to the decomposition pipeline through the air inlet, and the detector is connected to the air outlet.

[0007] Preferably, the oxidation furnace comprises an oxidation furnace tube sleeved on the analysis pipe, an oxidant arranged in the oxidation furnace tube, and an oxidation furnace heating device wrapped around the outer circumference of the oxidation furnace tube, and the air inlet is arranged at one end of the oxidation furnace tube away from the analysis furnace.

[0008] Furthermore, the organic carbon element carbon analyzer also includes a heat insulation layer arranged between the analysis furnace and the oxidation furnace.

[0009] Preferably, the analysis furnace also includes a sealed cavity which is arranged around the outer circumference of the analysis furnace tube and is enclosed together with the analysis furnace tube, and the analysis furnace heating device is arranged in the sealed cavity; the organic carbon element carbon analyzer also includes an air intake valve group, and a first gas pipeline and a second gas pipeline which are both connected to the air intake valve group, the first gas pipeline is connected to the sealed cavity and is used to introduce the protective gas output by the air intake valve group into the sealed cavity, and the second gas pipeline is connected to the analysis furnace tube and is used to introduce the atmospheric sample output by the air intake valve group into the analysis furnace tube.

[0010] Preferably, the organic carbon element carbon analyzer also includes a power pump, an exhaust solenoid valve, a first exhaust pipe and a second exhaust pipe, the first exhaust pipe is connected to the sealed chamber, the second exhaust pipe is connected to the analysis pipe, the exhaust solenoid valve includes two input ends and an output end, the two input ends are respectively connected to the first exhaust pipe and the second exhaust pipe one by one, the output end is connected to the power pump and can be switchably connected to one of the two input ends.

[0011] More preferably, the first exhaust pipeline and the first gas delivery pipeline are arranged on two opposite sides of the sealed cavity.

[0012] Preferably, the organic carbon element carbon analyzer also includes a laser detection device, which includes a laser emitter, a first laser detector and a second laser detector. The laser emitter is used to emit laser toward the filter membrane, and the first laser detector and the second laser detector are used to receive the transmitted laser passing through the filter membrane and the reflected laser reflected by the filter membrane, respectively.

[0013] Preferably, the laser emitter includes a first laser emitter disposed on the back side of the filter membrane, wherein part of the laser emitted by the first laser emitter toward the filter membrane passes through the filter membrane to form a first transmitted laser, and part is reflected by the filter membrane to form a first reflected laser, the first laser detector is disposed on the front side of the filter membrane and is used to receive the first transmitted laser, and the second laser detector is disposed on the back side of the filter membrane and is used to receive the first reflected laser.

[0014] More preferably, the laser emitter also includes a second laser emitter disposed on the front side of the filter membrane, and part of the laser emitted by the second laser emitter toward the filter membrane passes through the filter membrane to form a second transmitted laser and is received by the second laser detector, and part is reflected by the filter membrane to form a second reflected laser and is received by the first laser detector.

[0015] Preferably, the laser modulation frequencies of the first laser emitter and the second laser emitter are different, and the first laser detector and the second laser detector are both provided with a frequency demodulation module and can distinguish and measure lasers of different frequencies through the frequency demodulation module.

[0016] The present invention has the following beneficial effects:

[0017] 1. In the organic carbon element carbon analyzer provided by the embodiment of the present invention, the oxidation furnace is arranged around the periphery of the analysis pipeline, and the analysis pipeline is heated by the temperature of the oxidation furnace itself, so that the entire gas path between the analysis furnace and the oxidation furnace is in a high temperature state, which greatly weakens the adsorption capacity of the analysis pipeline for the analysis gas, thereby reducing sample loss and improving the accuracy of the detection results. Secondly, this structure can also effectively reduce the distance between the oxidation furnace and the analysis furnace, making the overall structure more compact, facilitating the realization of miniaturized design and having high strength and not easy to damage.

[0018] 2. In the carbon analyzer for organic carbon elements provided by the embodiment of the present invention, the analysis furnace includes a sealed cavity arranged around the outer periphery of the analysis furnace tube and isolated from the analysis furnace tube. By introducing a protective gas into the sealed cavity and discharging the air in the sealed cavity, the sealed cavity is in an oxygen-free or low-oxygen space, and the analysis furnace heating device is heated in the oxygen-free or low-oxygen space, thereby avoiding oxidation of the analysis furnace heating device at high temperatures, thereby increasing the service life of the analysis furnace heating device. In the cooling stage, the analysis furnace tube can be quickly cooled by introducing the protective gas into the sealed cavity, so that the filter membrane can quickly meet the temperature requirements of the next batch of sample detection. Compared with the cooling method through the heat dissipation fan, the heat dissipation efficiency and detection efficiency are effectively improved, and the noise and vibration of the equipment during operation are reduced to ensure operational stability.

[0019] 3. In the organic carbon elemental carbon analyzer provided by the embodiment of the present invention, since the first laser emitter is arranged on the back side of the filter membrane, part of the laser emitted by it passes through the filter membrane to form a first transmitted laser, and part is reflected by the filter membrane to form a first reflected laser. According to the intensity change of the first reflected laser, the influence of the change of the light source intensity and the optical properties of the filter membrane in the first transmitted laser can be effectively eliminated, and the laser intensity change data only affected by the sample concentration on the front side of the filter membrane is calculated, thereby accurately segmenting the organic carbon and elemental carbon, and improving the detection accuracy of organic carbon and elemental carbon.

[0020] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0022] Figure 1 A schematic diagram of the structure of an organic carbon element carbon analyzer provided by an embodiment of the present invention;

[0023] Figure 2 A schematic structural diagram of an organic carbon element carbon analyzer provided by another embodiment of the present invention;

[0024] Figure 3 A step diagram of a laser detection method provided by an embodiment of the present invention;

[0025] Figure 4 A step diagram of a laser detection method provided by another embodiment of the present invention.

[0026] Legend:

[0027] 1000. Organic carbon element carbon analyzer; 1. Intake valve group; 11. First gas pipeline; 12. Second gas pipeline; 2. Analysis furnace; 21. Analysis furnace tube; 22. Analysis furnace heating wire; 23. Filter membrane; 24. Sealed chamber; 3. Analysis pipeline; 4. Oxidation furnace; 41. Oxidation furnace tube; 42. Oxidation furnace heating wire; 43. Connecting pipeline; 5. Detector; 51. Detection solenoid valve; 6. Power pump; 7. Exhaust solenoid valve; 71. First exhaust pipeline; 72. Second exhaust pipeline; 8. Laser detection device; 81. Laser emitter; 811. First laser emitter; 812. Second laser emitter; 82. First laser detector; 83. Second laser detector; 84. First spectrometer; 85. Second spectrometer. DETAILED DESCRIPTION

[0028] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0029] Figures 1 to 4 The organic carbon elemental carbon analyzer provided in an embodiment of the present invention is collectively shown, which is used to detect the content of organic carbon and elemental carbon in air particulate matter. Due to its small and compact structure and the absence of a low-temperature area between the decomposition furnace and the oxidation furnace, the adsorption loss of the decomposition gas in the low-temperature area is effectively avoided, thereby improving the accuracy of organic carbon and elemental carbon detection.

[0030] like Figure 1 As shown, the organic carbon elemental carbon analyzer 1000 includes a decomposition furnace 2, a decomposition pipeline 3, an oxidation furnace 4 and a detector 5 which are connected in sequence. The decomposition furnace 2 is used to separate the organic carbon and elemental carbon in the atmospheric sample, and the organic carbon and elemental carbon can be decomposed by the decomposition furnace 2 and enter the oxidation furnace 4 along the decomposition pipeline 3 for oxidation. Finally, the detector 5 detects the concentration of carbon dioxide output by the oxidation furnace 4 to calculate the content of organic carbon and elemental carbon, or detects the concentration of methane converted from the carbon dioxide output by the oxidation furnace 4 to calculate the content of organic carbon and elemental carbon.

[0031] Specifically, the analysis furnace 2 includes a analysis furnace tube 21 and a analysis furnace heating device arranged on the analysis furnace tube 21, and a filter membrane 23 fixed in the analysis furnace tube 21. The filter membrane 23 is preferably a quartz filter membrane, and the surface of the filter membrane 23 is arranged perpendicularly to the gas flow direction of the analysis furnace tube 21, so that the filter membrane 23 is fixed in the analysis furnace tube 21 and can filter and collect particulate matter in the atmospheric sample flowing through the analysis furnace tube 21. The analysis furnace heating device is specifically a analysis furnace heating wire 22 wound on the analysis furnace tube 21, which is used to heat the internal space of the analysis furnace tube 21 so that the filter membrane 23 is in a high temperature environment, thereby thermally decomposing the organic carbon or elemental carbon in the particulate matter on the surface of the filter membrane 23.

[0032] The desorption pipeline 3 is coaxially arranged with the desorption furnace tube 21 and is interconnected, that is, the desorption pipeline 3 and the desorption furnace tube 21 are both linear structures and are butted front and back along the same straight line to form a linear gas flow channel. In other embodiments, the desorption pipeline 3 can also be formed by directly extending the desorption furnace tube 21.

[0033] The oxidation furnace 4 includes an oxidation furnace tube 41 sleeved on the analysis pipeline 3 and an oxidation furnace heating device arranged on the oxidation furnace tube 41. The oxidation furnace heating device is specifically an oxidation furnace heating wire 42 wound around the outer periphery of the oxidation furnace tube 41. The analysis furnace tube 41 includes a cavity with a certain thickness to form a receiving space around the analysis pipeline 3, and the receiving space is built with an oxidant (not shown in the figure, the same below). An air inlet and an air outlet are respectively provided at the opposite ends of the oxidation furnace tube 41, and a connecting pipe 43 connected to the analysis pipeline 3 is provided on the air inlet, and the air outlet is connected to the detector 5. Specifically, the oxidation furnace tube 41 has a cylindrical structure and forms an annular oxidation channel with the analysis pipeline 3. Of course, the oxidation furnace tube 41 is not limited to a cylindrical structure, and the oxidation channel is not limited to a ring.

[0034] The specific detection process of the organic carbon elemental carbon analyzer 1000 includes: inputting an atmospheric sample containing particulate matter into the analysis furnace tube 21, so that the particulate matter in the sample gas is filtered and collected by the filter membrane 23 in the analysis furnace tube 21, and the particulate matter is attached to the surface of the filter membrane 23. Then, an oxygen-free carrier gas is input into the analysis furnace tube 21, and the oxygen-free carrier gas can be specifically helium, so as to completely replace the gas in the analysis furnace tube 21 to form an oxygen-free environment, so that the filter membrane 23 is in an oxygen-free environment, and at this time, the analysis furnace 21 is gradually heated by the analysis furnace heating wire 22, so that most of the organic carbon on the surface of the filter membrane 23 is thermally decomposed and escaped (a small part of the organic carbon is converted into elemental carbon and continues to adhere to the surface of the filter membrane 23), and the analyzed organic carbon gas enters the oxidation furnace tube 41 through the analysis pipeline 3, and is oxidized and converted into carbon dioxide by the oxidation furnace 4 through the continuous heating of the oxidation furnace heating wire 42 and the chemical reaction of the oxidant, so that it can be detected by the detector 5 to determine the organic carbon content in the sample. When all the organic carbon in the sample is analyzed, an aerobic carrier gas is input into the analysis furnace tube 21. The aerobic carrier gas can specifically be a helium-oxygen mixed gas to completely replace the gas in the analysis furnace tube 21 to form an aerobic environment, so that the filter membrane 23 is in an aerobic environment. At this time, the analysis furnace 21 is gradually heated by the analysis furnace heating wire 22, so that the elemental carbon on the surface of the filter membrane 23 is thermally decomposed and escapes. The analyzed elemental carbon gas enters the oxidation furnace tube 41 through the analysis pipeline 3. Through the continuous heating of the oxidation furnace heating wire 42 and the chemical reaction of the oxidant, the elemental carbon gas is oxidized by the oxidation furnace 4 and converted into carbon dioxide, which can be detected by the detector 5 to determine the elemental carbon content in the sample.

[0035] Furthermore, to ensure the accuracy of the test results, after the elemental carbon content is detected, a calibration gas can be input into the analysis furnace tube 21. The calibration gas can specifically be methane gas, which can directly pass through the filter membrane 23 into the oxidation furnace tube 41, and be detected by the detector 5 after being oxidized by the oxidation furnace 41. The detection result of the calibration gas by the detector 5 is compared with the standard carbon content in the calibration gas, and the detection error of the organic carbon elemental carbon analyzer 1000 is calculated, and then the detection results of the organic carbon and elemental carbon are calibrated according to the detection error to obtain more accurate detection data.

[0036] Furthermore, the organic carbon element carbon analyzer 1000 also includes a detection solenoid valve 51 disposed between the detector 5 and the oxidation furnace tube 41 , and the detection time of the detector 5 is controlled by opening and closing the detection solenoid valve 51 to ensure the accuracy of the detection result.

[0037] It is worth noting that, since the oxidation furnace 4 is arranged around the periphery of the analysis pipeline 3, the temperature of the oxidation furnace 4 itself is used to heat and insulate the analysis pipeline 3, so that the entire gas path between the analysis furnace 2 and the oxidation furnace 4 is in a high temperature state, avoiding the existence of a low-temperature area in the analysis pipeline 3, greatly weakening the adsorption capacity of the analysis pipeline 3 for the analysis gas, thereby reducing the loss of the sample during the transfer process and improving the accuracy of the test results. Secondly, this structure can also effectively reduce the distance between the oxidation furnace 4 and the analysis furnace 2, making the overall structure of the organic carbon element carbon analyzer 1000 more compact, facilitating the realization of a miniaturized design, and having high strength and not easy to damage.

[0038] Preferably, the air inlet is arranged at the end of the oxidation furnace tube 41 away from the decomposition furnace 2, that is, the oxidation furnace tube 41 is connected to the end of the decomposition pipe 3 away from the decomposition furnace 2, so as to avoid the retention of samples in the gas at the end of the decomposition pipe 3 away from the decomposition furnace 2 and avoid excessive dead volume, so that the pyrolysis gas in the decomposition pipe 3 can basically be transferred to the oxidation furnace tube 41, thereby ensuring the accuracy of the detected samples.

[0039] Preferably, the decomposition furnace 2 further includes a sealed cavity 24, which surrounds the outer circumference of the decomposition furnace tube 21 and is formed together with the decomposition furnace tube 21, that is, an independent sealed space is formed on the outer circumference of the decomposition furnace tube 21, and the decomposition furnace heating wire 22 is arranged in the sealed cavity 24.

[0040] Furthermore, the organic carbon element carbon analyzer 1000 also includes an intake valve group 1, and a first gas pipeline 11 and a second gas pipeline 12 both connected to the intake valve group 1, the first gas pipeline 11 is connected to the sealed cavity 24 and is used to introduce the protective gas output by the intake valve group 1 into the sealed cavity 24, and the second gas pipeline 12 is connected to the analysis furnace tube 21 and is used to switchably introduce atmospheric samples, oxygen-free carrier gas, oxygen carrier gas, calibration gas and other gases output by the intake valve group 1 into the analysis furnace tube 21.

[0041] Furthermore, the organic carbon element carbon analyzer 1000 also includes a power pump 6, a first exhaust pipe 71 and a second exhaust pipe 72, wherein the first exhaust pipe 71 is connected to the sealed chamber 24, and the second exhaust pipe 72 is connected to an end of the decomposition pipe 3 away from the intake valve group 1, and the exhaust solenoid valve 7 includes two input ends and one output end, wherein the two input ends are respectively connected to the first exhaust pipe 71 and the second exhaust pipe 72 in a one-to-one correspondence, and the output end is connected to the power pump 6 and can be switched to be connected to one of the two input ends. So that the power pump 6 can be connected to the first exhaust pipe 71 or the second exhaust pipe 72 under the control of the exhaust solenoid valve 7, so that the gas in the sealed chamber 24 or the gas in the decomposition furnace 2, the decomposition pipe 3 and the oxidation furnace 4 can be flexibly switched through a power pump 6, thereby simplifying the structure and reducing the cost, and achieving the function of exhausting and controlling the gas flow.

[0042] Since a sealed cavity 24 is provided outside the desorption furnace tube 21 to seal and wrap the desorption furnace heating wire 22, the air inlet valve group 1 can fill the sealed cavity 24 with a protective gas along the first gas pipeline 11. The protective gas can be an oxygen-free or low-oxygen gas, so that the air in the sealed cavity 24 can be discharged along the first exhaust pipeline 71, so that the sealed cavity 24 is in an oxygen-free or low-oxygen space, and the desorption furnace heating wire 22 is heated in the oxygen-free or low-oxygen space, thereby preventing the desorption furnace heating wire 22 from being oxidized at high temperature and improving the service life of the desorption furnace heating wire 22. In addition, the sealed cavity 24 seals and wraps the desorption furnace heating wire 22 in a sealed space, which can play a role in gathering heat, which is beneficial to reducing the heat loss of the desorption furnace heating wire 22 and improving the heating efficiency and insulation effect.

[0043] In addition, since the maximum temperature of the analysis furnace 2 during analysis can reach 850°C during the detection process, the analysis furnace tube 21 needs to be quickly cooled down before the next sample detection to avoid the residual high temperature in the analysis furnace tube 21 during the sampling stage of the next detection directly pyrolyzing the organic carbon or elemental carbon in the sample, thereby affecting the subsequent detection results. In this regard, existing organic carbon elemental carbon analyzers usually use a large air volume heat dissipation fan for blowing and cooling, which has a poor cooling effect and has large noise and vibration, and cannot guarantee the stable operation of the equipment, resulting in a poor user experience and a large instrument size.

[0044] In the organic carbon element carbon analyzer 1000 provided in the present embodiment, the analysis furnace 2 includes a sealed cavity 24 surrounding the outer periphery of the analysis furnace tube 21. By introducing an oxygen-free protective gas (such as nitrogen) into the sealed cavity 24, the analysis furnace tube 21 and the analysis furnace heating wire 22 can be quickly cooled down, and the temperature of the analysis furnace tube 21 can be quickly reduced from 850°C to about 400°C. When the temperature of the analysis furnace tube 21 drops below 400°C, the air can be input into the sealed cavity 24 by switching the air path through the intake valve group 1. At the same time, the input air is quickly discharged from the sealed cavity 24 by the power pump 6 through the first exhaust pipe 71. The power pump 6 preferably adopts a large-flow air pump. In the absence of resistance, the flow rate can reach 80L / min, so that rapid ventilation can be achieved in the sealed cavity 24, and the rapid circulation of air can achieve the effect of rapid cooling. Therefore, in the high temperature stage, oxygen-free protective gas is used for rapid cooling, which can prevent the oxidation of the analysis furnace heating wire 22, and in the semi-high temperature stage, it is switched to the air extraction type heat dissipation mode to ensure the service life of the analysis furnace heating wire 22, while reducing the consumption of protective gas such as nitrogen and reducing the cooling cost. In addition, since there is no heat dissipation fan, the volume of the organic carbon element carbon analyzer 1000 is further reduced, and the noise and vibration during operation can be reduced.

[0045] Preferably, the first exhaust pipe 71 and the first gas supply pipe 11 are arranged on opposite sides of the sealed cavity 24, so that the protective gas output by the first gas supply pipe 11 first passes through the decomposition furnace heating wire 22 and is then discharged from the first exhaust pipe 71, that is, a gas flow channel is naturally formed around the decomposition furnace heating wire 22, so that the protective gas can flow around the decomposition furnace tube 21 and the decomposition furnace heating wire 22, thereby improving the cooling effect on the decomposition furnace tube 21 during gas circulation.

[0046] Furthermore, the organic carbon element carbon analyzer 1000 also includes a heat insulation layer (not shown in the figure, the same below) arranged between the analysis furnace 2 and the oxidation furnace 4. The heat insulation layer can be made of heat insulation materials such as thermal insulation cotton to prevent the high temperature of the oxidation furnace 4 itself from affecting the temperature of the analysis furnace 2, thereby ensuring the temperature control effect of the analysis furnace 2.

[0047] Preferably, the organic carbon element carbon analyzer 1000 also includes a laser detection device 8, which includes a laser emitter 81, a first laser detector 82 and a second laser detector 83. The laser emitter 81 is used to emit a laser toward the filter membrane 23, and the emitted laser partially passes through the filter membrane 23 to form a transmitted laser, and partially is reflected by the filter membrane 23 to form a reflected laser. The first laser detector 82 and the second laser detector 83 are respectively arranged on opposite sides of the filter membrane 23 and are used to receive the transmitted laser and the reflected laser, respectively. When the laser emitter 81 is arranged on the front side of the filter membrane 23, that is, the laser emitter 81 emits laser toward the side of the filter membrane 23 to which organic carbon and elemental carbon are attached, the transmitted laser and the reflected laser are both affected by the cracked carbon / elemental carbon concentration on the surface of the filter membrane 23. The first laser detector 82 and the second laser detector 83 are used to detect the intensity of the transmitted laser and the reflected laser, and the change process of the cracked carbon / elemental carbon concentration on the surface of the filter membrane 23 can be fed back in real time, thereby realizing the segmentation of the organic carbon and elemental carbon content by the thermal light transmission method and the thermal light reflection method.

[0048] Specifically, the optical correction method is used to determine the segmentation point of organic carbon and elemental carbon, based on the following assumptions: 1) elemental carbon is the only light-absorbing substance, 2) cracked carbon has the same light absorption coefficient as the original elemental carbon, and 3) cracked carbon is oxidized and decomposed before the original elemental carbon. In the process of pyrolysis of organic carbon, since part of the organic carbon will be converted into cracked carbon and attached to the surface of the filter membrane 23, the intensity of the transmitted laser and the reflected laser will decrease as the concentration of cracked carbon increases. In the process of pyrolysis of the cracked carbon / elemental carbon, as the concentration of cracked carbon / elemental carbon gradually decreases, the intensity of the transmitted laser and the reflected laser will gradually increase. When the intensity of the transmitted laser and the reflected laser increases to the intensity before the pyrolysis of the organic carbon, the node can be determined as the node of the initial elemental carbon concentration, that is, at this time, the cracked carbon converted from the organic carbon has been completely pyrolyzed, and the content of organic carbon and elemental carbon can be accurately segmented.

[0049] Preferably, the laser emitter 81 includes a first laser emitter 811 disposed on the back side of the filter membrane 23. The laser emitted by the first laser emitter 811 toward the filter membrane 23 partially passes through the filter membrane 23 to form a first transmitted laser, and partially is reflected by the filter membrane 23 to form a first reflected laser. The first laser detector 82 is disposed on the front side of the filter membrane 23 and is used to receive the first transmitted laser. The second laser detector 83 is disposed on the back side of the filter membrane 23 and is used to receive the first reflected laser. When the atmospheric sample containing particulate matter passes through the filter membrane 23, the filter membrane 23 can intercept the particulate matter in the atmospheric sample on the front side of the filter membrane 23, and a small part penetrates into the shallow layer and the middle of the filter membrane 23. When the filter membrane 23 reaches a certain thickness, the filter membrane 23 can completely intercept the particulate matter at the front side thereof, and does not exist on the back side of the filter membrane 23. Therefore, the intensity of the first transmitted laser penetrating from the back side of the filter membrane 23 to the front side of the filter membrane 23 is affected by the intensity of the light source, the optical properties of the filter membrane and the concentration of cracked carbon / elemental carbon, while the intensity of the first reflected laser directly reflected from the back side of the filter membrane 23 is only affected by the intensity of the light source and the optical properties of the filter membrane.

[0050] Secondly, during the anaerobic pyrolysis of organic carbon by the organic carbon elemental carbon analyzer 1000, part of the organic carbon will be converted into cracked carbon and attached to the surface of the filter membrane 23. At this time, the first transmitted laser intensity decreases with the increase of elemental carbon concentration. During the pyrolysis of elemental carbon and cracked carbon by the organic carbon elemental carbon analyzer 1000, as the concentrations of elemental carbon and cracked carbon gradually decrease, the first transmitted laser intensity gradually increases. When the first transmitted laser intensity increases to the intensity before the pyrolysis of the organic carbon, the node can be judged as the node of the initial elemental carbon concentration, that is, at this time, the elemental carbon converted from the organic carbon has been completely pyrolyzed, thereby realizing the separation of organic carbon and elemental carbon.

[0051] Therefore, according to the intensity change of the first reflected laser, the influence of the light source intensity and the change of the optical properties of the filter membrane in the first transmitted laser can be eliminated, so that the first transmitted laser is only affected by the cracked carbon and elemental carbon concentrations, so as to accurately segment the organic carbon and elemental carbon, thereby achieving accurate measurement of the organic carbon and elemental carbon content. In other words, the back-reflected light is used as the reference light to track and correct the intensity of the transmitted light in real time, that is, the influence of the light source intensity fluctuation on the intensity of the transmitted light is corrected, and the influence of the change of the optical properties caused by the temperature change of the filter membrane on the intensity of the transmitted light is also corrected. This optical path can be applied to the measurement of organic carbon and elemental carbon by the thermal light transmission method to achieve accurate segmentation of organic carbon and elemental carbon, thereby improving the detection accuracy of organic carbon and elemental carbon.

[0052] It should be understood that the flow path of samples, carrier gases and other gases is to penetrate through the back side of the filter membrane 23 along the front side of the filter membrane 23, that is, the front side of the filter membrane 23 is used to filter and collect particulate matter, and the back side of the filter membrane 23 is used for gas leakage.

[0053] Furthermore, the laser detection device 8 also includes a first beam splitter 84 arranged at the front end of the first laser emitter 811, the first beam splitter 84 is inclined at an angle of 45 degrees relative to the surface of the filter 23, the light emitting direction of the first laser emitter 811 is perpendicular to the surface of the filter 23, the light incident direction of the second laser detector 83 is parallel to the surface of the filter 23, at least part of the laser emitted by the first laser emitter 811 passes through the first beam splitter 84 and shines on the filter 23, and the first reflected laser can be reflected by the first beam splitter 84 and then change direction to enter the second laser detector 83, and the outgoing light and the reflected light are separated by the first beam splitter 84.

[0054] In other embodiments, when the first laser emitter 811 is unable to emit laser light toward the filter 23 in a direction perpendicular to the surface of the filter 23 due to the limitation of the structure and position of itself or other components, the light emitting direction of the first laser emitter 811 may also be set at other angles relative to the surface of the filter 23. It is only necessary to ensure that the light emitting direction of the first laser emitter 811 is toward the filter 23 to form the first transmitted laser and the first reflected laser. Similarly, it is sufficient to ensure that the incident light direction of the second laser detector 83 is staggered from the filter 23. The angle of inclination of the first beam splitter 84 relative to the surface of the filter 23 changes with the incident light direction of the first reflected laser and the second laser detector 83, so that the first reflected laser can enter the second laser detector 83 after changing the angle through the reflection of the first beam splitter 84.

[0055] Please combine Figure 3 This embodiment also provides a laser detection method using the above-mentioned laser detection device 8 for detection, and the laser detection method includes the following steps:

[0056] Step S100: The first laser emitter 811 emits a laser toward the back side of the filter membrane 23, and part of the laser emitted by the first laser emitter 811 passes through the front side of the filter membrane 23 to form a first transmitted laser, and part of the laser is reflected back by the back side of the filter membrane 23 to form a first reflected laser.

[0057] Since the intensity of the light source of the laser transmitter may fluctuate and drift during use, and the optical properties of the filter membrane 23 will change with the temperature change of the analysis furnace 2, the intensities of the first transmitted laser and the first reflected laser are affected by the intensity of the light source and the optical properties of the filter membrane. As a result, the intensity change data of the first transmitted laser cannot accurately reflect the concentration change process of organic carbon and elemental carbon, which causes the segmentation point of organic carbon and elemental carbon to change, making it impossible to accurately segment, thereby affecting the accurate measurement of the concentrations of organic carbon and elemental carbon.

[0058] At this time, the first laser emitter 811 is arranged on the back side of the filter membrane 23, and the filter membrane 23 intercepts the particles at the front side thereof, and the particles containing organic carbon and elemental carbon do not exist at the back side of the filter membrane 23. Therefore, when the first laser emitter 811 irradiates the back side of the filter membrane 23, the intensity of the first transmitted laser light will be affected by the intensity of the light source, the optical properties of the filter membrane, and the concentration of the sample at the front side of the filter membrane, while the first reflected laser light reflected from the back side of the filter membrane 23 is only affected by the intensity of the light source and the optical properties of the filter membrane.

[0059] Step S200 : receiving the first transmitted laser through the first laser detector 82 , and receiving the first reflected laser through the second laser detector 83 .

[0060] The incident light direction of the first laser detector 82 is toward the filter membrane 23, and the first transmitted laser directly enters the first laser detector 82 and is detected by it. The incident light direction of the second laser detector 83 is offset from the filter membrane 23, and the first reflected laser is reflected by the first beam splitter 84 and changes direction before entering the second laser detector 83 and is detected by it.

[0061] Step S300: based on the intensity variation data of the first reflected laser, the influence of the changes in the light source intensity and the optical properties of the filter membrane in the first transmitted laser is eliminated, and the laser intensity variation data affected only by the sample concentration on the front side of the filter membrane is calculated.

[0062] Since the intensity of the first transmitted laser is affected by the intensity of the light source, the optical properties of the filter membrane and the sample concentration on the front of the filter membrane, while the first reflected laser is only affected by the intensity of the light source and the optical properties of the filter membrane, the intensity change data of the first reflected laser and the intensity change data of the first transmitted laser can be processed one-to-one to eliminate the influence of the changes in the intensity of the light source and the optical properties of the filter membrane in the first transmitted laser, so that the first transmitted laser is only affected by the sample concentration on the front of the filter membrane, and the change process of the sample concentration on the front of the filter membrane 23 is accurately fed back through the laser intensity change data of the first transmitted laser. Therefore, when the laser detection method is applied to the organic carbon elemental carbon analyzer 1000, the concentration change process of organic carbon and elemental carbon can be accurately reflected, and then the organic carbon and elemental carbon on the filter membrane 23 can be accurately segmented, thereby improving the detection accuracy of the organic carbon and elemental carbon concentrations. That is to say, the first reflected laser (back-reflected laser) received by the second laser detector is used as a reference light to track and correct the intensity of the first transmitted laser in real time, that is, the influence of the light source intensity fluctuation on the first transmitted laser intensity is corrected, and the influence of the change of optical properties caused by the filter membrane temperature change on the first transmitted laser intensity is corrected, thereby achieving accurate segmentation of organic carbon and elemental carbon, thereby improving the detection accuracy of organic carbon and elemental carbon.

[0063] like Figure 2 As shown, in another embodiment, the laser emitter 81 also includes a second laser emitter 812 disposed on the front side of the filter membrane 23. Of the laser emitted by the second laser emitter 812 toward the filter membrane 23, part passes through the back side of the filter membrane 23 to form a second transmitted laser and is received by the second laser detector 83, and part is directly reflected back by the front side of the filter membrane 23 to form a second reflected laser and is received by the first laser detector 82.

[0064] Furthermore, the first laser emitter 811 and the second laser emitter 812 have different laser modulation frequencies, and the first laser detector 82 and the second laser detector 83 are both provided with a frequency demodulation module and can distinguish and measure lasers with different modulation frequencies through the frequency demodulation module, so that when the lasers emitted by the first laser emitter 811 and the second laser emitter 812 are received at the same time, the lasers emitted by the first laser emitter 811 and the second laser emitter 812 can be distinguished, and the intensity change data of the two lasers can be detected respectively.

[0065] Furthermore, the light emitting direction of the second laser emitter 812 is parallel to the surface of the filter membrane 23, and the laser detection device 8 further includes a second beam splitter 85 disposed at the front end of the second laser emitter 812, and the second beam splitter 85 is also tilted at an angle of 45 degrees relative to the surface of the filter membrane 23. The laser emitted by the second laser emitter 812 can be reflected by the second beam splitter 85 and then change direction to illuminate the front of the filter membrane 23 in a direction perpendicular to the surface of the filter membrane 23, and the second reflected laser reflected by the filter membrane 23 can enter the first laser detector 82 after passing through the second beam splitter 85.

[0066] In other embodiments, when the second laser emitter 812 cannot emit laser light in a direction parallel to the surface of the filter membrane 23 due to the limitation of the structure or position of the second laser emitter 812 or other components, the light emitting direction of the second laser emitter 812 may also be set to be inclined relative to the surface of the filter membrane 23. Correspondingly, when the light emitting direction of the second laser emitter 811 is offset from the filter membrane 23, the angle of inclination of the second beam splitter 84 relative to the surface of the filter membrane 23 needs to be changed to follow the light emitting direction of the second laser emitter 811, so that the laser light emitted by the second laser emitter 811 can be directed toward the filter membrane 23 after being adjusted by the second beam splitter 84.

[0067] Please combine Figure 4 When the laser detection device 8 further includes a second laser emitter 812, the laser detection method specifically includes the following steps:

[0068] Step S100: The first laser emitter 811 emits a laser toward the back side of the filter membrane 23, and part of the laser emitted by the first laser emitter 811 passes through the filter membrane 23 to form a first transmitted laser, and part of the laser is reflected by the filter membrane 23 to form a first reflected laser. The intensity of the first transmitted laser is affected by the intensity of the light source, the optical properties of the filter membrane, and the concentration of the sample on the front side of the filter membrane, and the intensity of the first reflected laser is affected by the intensity of the light source and the optical properties of the filter membrane.

[0069] While the first laser emitter 811 emits laser, the second laser emitter 812 emits laser toward the front of the filter membrane 23, and the laser emitted by the second laser emitter 812 partially passes through the filter membrane 23 to form a second transmitted laser, and partially is reflected by the filter membrane to form a second reflected laser. The second transmitted laser and the second reflected laser are both affected by the intensity of the light source, the optical properties of the filter membrane, and the concentration of the sample on the front of the filter membrane.

[0070] Step S200 : receiving the first transmitted laser and the second reflected laser through the first laser detector 82 , and receiving the first reflected laser and the second transmitted laser through the second laser detector 83 .

[0071] Step S300: Based on the intensity change data of the first reflected laser, the influence of changes in the light source intensity and the optical properties of the filter membrane in the first transmitted laser, the second transmitted laser, and the second reflected laser is eliminated, and multiple groups of laser intensity change data that are only affected by the sample concentration on the front side of the filter membrane are calculated.

[0072] First, according to the intensity change of the first reflected laser, the second transmitted laser and the second reflected laser formed by the second laser emitter 812 can be corrected in real time to eliminate the influence caused by the change of the light source intensity and the optical properties of the filter membrane, and to achieve accurate segmentation of the organic carbon and elemental carbon content of the two methods of thermal light transmission method and thermal light reflection method, thereby improving the detection accuracy. Secondly, the segmentation point of organic carbon and elemental carbon determined by the intensity change of the first transmitted laser formed by the first laser emitter 811 after passing through the filter membrane can be combined with the segmentation point of organic carbon and elemental carbon determined by the intensity change of the second transmitted laser and / or the second reflected laser formed by the second laser emitter 812, so as to achieve mutual confirmation between multiple segmentation points, and further improve the accuracy of the segmentation of organic carbon and elemental carbon content through multiple verification and correction data, thereby greatly reducing the error of the segmentation of organic carbon and elemental carbon concentration.

[0073] In summary, the organic carbon elemental carbon analyzer 1000 provided in the embodiment of the present invention has strong stability and reliability, a long service life, can be miniaturized, can accurately find the dividing point between organic carbon and elemental carbon, and the detection results are accurate and reliable.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An organic carbon element carbon analyzer, characterized in that, The invention comprises a decomposition furnace (2), a decomposition pipeline (3), an oxidation furnace (4) and a detector (5); the decomposition furnace (2) comprises a decomposition furnace tube (21) and a filter membrane (23) arranged in the decomposition furnace tube (21), and a decomposition furnace heating device arranged on the decomposition furnace tube (21) for heating the filter membrane (23); the decomposition pipeline (3) is connected to the decomposition furnace tube (21); the oxidation furnace (4) is arranged around the outer circumference of the decomposition pipeline (3) and is provided with an air inlet and an air outlet at two opposite ends; the oxidation furnace (4) is connected to the decomposition pipeline (3) through the air inlet; and the detector (5) is connected to the air outlet; The oxidation furnace (4) comprises an oxidation furnace tube (41) sleeved on the desorption pipe (3) and an oxidation furnace heating device arranged on the oxidation furnace tube (41), wherein the oxidation furnace tube (41) comprises a cavity with a certain thickness so as to form a receiving space on the outer periphery of the desorption pipe (3), wherein an oxidant is arranged in the receiving space; The organic carbon element carbon analyzer further comprises a laser detection device (8), wherein the laser detection device (8) comprises a laser emitter (81), a first laser detector (82) and a second laser detector (83), wherein the laser emitter (81) is used to emit laser light toward the filter membrane (23), and the first laser detector (82) and the second laser detector (83) are used to receive the transmitted laser light passing through the filter membrane (23) and the reflected laser light reflected by the filter membrane (23), respectively; The laser emitter (81) comprises a first laser emitter (811) disposed on the back side of the filter membrane (23); of the laser light emitted by the first laser emitter (811) toward the filter membrane (23), part passes through the filter membrane (23) to form a first transmitted laser light, and part is reflected by the filter membrane (23) to form a first reflected laser light; the first laser detector (82) is disposed on the front side of the filter membrane (23) and is used to receive the first transmitted laser light; and the second laser detector (83) is disposed on the back side of the filter membrane (23) and is used to receive the first reflected laser light; The filter membrane (23) is used to retain particles at the front side thereof and prevent particles from existing at the back side of the filter membrane (23).

2. The organic carbon element carbon analyzer according to claim 1, characterized in that: The air inlet is arranged at an end of the oxidation furnace tube (41) away from the desorption furnace (2).

3. The organic carbon element carbon analyzer according to claim 1, characterized in that: The organic carbon element carbon analyzer also includes a heat insulation layer arranged between the analysis furnace (2) and the oxidation furnace (4).

4. The organic carbon element carbon analyzer according to claim 1, characterized in that: The analysis furnace (2) further comprises a sealed cavity (24) arranged around the outer circumference of the analysis furnace tube (21) and enclosed with the analysis furnace tube (21), and the analysis furnace heating device is arranged in the sealed cavity (24); The organic carbon element carbon analyzer further comprises an intake valve group (1), and a first gas pipeline (11) and a second gas pipeline (12) both connected to the intake valve group (1), wherein the first gas pipeline (11) is connected to the sealed cavity (24) and is used for introducing the protective gas output by the intake valve group (1) into the sealed cavity (24), and the second gas pipeline (12) is connected to the analysis furnace tube (21) and is used for introducing the atmospheric sample output by the intake valve group (1) into the analysis furnace tube (21).

5. The organic carbon element carbon analyzer according to claim 4, characterized in that: The organic carbon element carbon analyzer also includes a power pump (6), an exhaust solenoid valve (7), a first exhaust pipe (71) and a second exhaust pipe (72), wherein the first exhaust pipe (71) is connected to the sealed chamber (24), and the second exhaust pipe (72) is connected to the analysis pipe (3); the exhaust solenoid valve (7) includes two input ends and one output end, wherein the two input ends are respectively connected to the first exhaust pipe (71) and the second exhaust pipe (72) in a one-to-one correspondence, and the output end is connected to the power pump (6) and can be switchably connected to one of the two input ends.

6. The organic carbon element carbon analyzer according to claim 5, characterized in that: The first exhaust pipe (71) and the first gas supply pipe (11) are arranged on two opposite sides of the sealed cavity (24).

7. The organic carbon element carbon analyzer according to claim 1, characterized in that: The laser emitter (81) further comprises a second laser emitter (812) arranged on the front side of the filter membrane (23); of the laser light emitted by the second laser emitter (812) toward the filter membrane (23), part of it passes through the filter membrane (23) to form a second transmitted laser light and is received by the second laser detector (83), and part of it is reflected by the filter membrane (23) to form a second reflected laser light and is received by the first laser detector (82).

8. The organic carbon element carbon analyzer according to claim 7, characterized in that: The laser modulation frequencies of the first laser emitter (811) and the second laser emitter (812) are different, and the first laser detector (82) and the second laser detector (83) are both provided with a frequency demodulation module and can perform differentiated measurement on lasers of different frequencies through the frequency demodulation module.

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