CN105203502A - In-situ online collection analysis meter and method for aerosol carbonaceous components - Google Patents

Abstract

The invention discloses an aerosol carbonaceous component in-situ online collection analyzer and an operation method. The instrument includes a carrier gas and a sampling-analysis gas circuit system. The carrier gas gas circuit system includes He main gas, He purge gas, He/ Ox gas and He/CH ₄ gas gas path; sampling-analysis gas path system includes sampling, desorption-oxidation furnace and analysis gas path; online collection and analysis methods include sampling, purging, OC analysis, EC analysis, methane quantification, methane Calibration, instrument cooling and standby. The invention does not set other structures except the quartz film in the laser light path to ensure the accuracy of the light path; it realizes the simultaneous correction of the cutting point by the transmitted laser light and the reflected laser light, and comprehensively reflects the change of the film blackness; the valve body is designed so that the methane internal standard The quantitative error of the gas is greatly reduced, ensuring the stability of the internal standard gas, and improving the accuracy of EC and OC measurement results; the design of the gas path ensures that the carrier gas composition in the system is single and the system background is stable during the analysis stage.

Description

An aerosol carbonaceous component in-situ online acquisition analyzer and method thereof

technical field

The invention relates to an environmental quality monitoring instrument, in particular to an aerosol carbonaceous component in-situ online collection analyzer and an online collection and analysis method thereof.

Background technique

Carbonaceous components in atmospheric aerosols usually account for 10-70% of the mass concentration of atmospheric fine particles and are an important component of atmospheric fine particles. It can be divided into three categories: organic carbon (Organic Carbon, OC), elemental carbon (Elemental Carbon, EC) and carbonic acid carbon (Carbonate Carbon, CC). OC refers to a mixture containing hundreds of organic compounds (such as aliphatics, aromatics, acids, etc.), mainly derived from emissions from primary combustion processes, biological emissions, and gaseous organic pollutants participating in photochemical reactions and gas particle conversion. process emissions. EC usually refers to a kind of amorphous carbon with very low crystallinity that is emitted directly after incomplete combustion of carbonaceous materials such as fossil fuels or biomass. CC mainly exists in coarse particles of soil and coal mine fly ash, and its mass concentration is much smaller than that of OC and EC, so it is generally ignored.

Carbonaceous components in atmospheric aerosols can have an impact on global climate, atmospheric visibility, and human health. As the most important optical absorption component in atmospheric aerosol, EC can not only absorb light from infrared to ultraviolet, but also deepen the color of particles, so that some particles that do not absorb radiation or absorb less radiation produce light absorption. , thereby increasing the positive radiative forcing. In addition, carbonaceous aerosols can also act as condensation nuclei to change the concentration and lifetime of cloud droplets in the atmosphere, indirectly affecting the Earth's radiation balance. In terms of visibility, the strong absorption of light by EC and the scattering of light by OC can significantly reduce the visibility of the regional atmosphere. In terms of human health, most of the carbonaceous components in aerosols exist in fine particles (0.1-1 μm), so it is easy to enter the lungs through the respiration of the human body, destroy the structure and function of the lungs, and cause chronic respiratory diseases, etc. . Therefore, it is of great significance to study the carbonaceous components of atmospheric aerosols, and it has become a hot spot in the field of environmental monitoring today.

At present, there are mainly two methods for the study of carbonaceous components in atmospheric aerosols: membrane sampling off-line analysis method and online sampling analysis method. Compared with the offline analysis method, the online sampling analysis method overcomes the shortcomings of low time resolution and large human interference, and has a larger application market. However, there are still some deficiencies in the structure and function of commercial online aerosol carbonaceous component analyzers: 1. The cutting point calibration method is single, and only one of the transmission laser calibration method or reflection laser calibration method is used, which cannot comprehensively reflect the film The change of blackness; 2. The heat on the quartz film is mainly transferred from the structure in contact with the quartz film inside the quartz tube and the surrounding air, and the heating is slow and uneven; 3. A quartz sheet is fired inside the furnace tube , it will be polluted during use, which will affect the accuracy of the optical path; 4. The use of carrier gas is wasteful and unreasonably distributed: the methane internal standard gas is discharged throughout the process, causing a large waste; the amount of carrier gas is not constant throughout the analysis process , changing from helium to helium+oxygen will cause background fluctuations and affect the measurement results. 5. The structure of the valve body controlling the methane quantitative loop has a large dead volume, which will lead to instability of the methane peak.

Contents of the invention

In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides an in-situ online collection and analysis instrument for aerosol carbonaceous components. The instrument does not set other structures in the laser optical path except the quartz film, which ensures the accuracy of the optical path; It also realizes the correction of the cutting point by the transmitted laser and the reflected laser at the same time, and comprehensively reflects the change of the film blackness; the design of the valve body greatly reduces the quantitative error of the methane internal standard gas, ensures the stability of the internal standard gas, and improves the organic carbon ( OrganicCarbon, OC) and elemental carbon (ElementalCarbon, EC) measurement results are accurate; the gas circuit design ensures that the composition of the carrier gas in the system is constant during the analysis stage, and the stability of the system background is guaranteed.

The working principle of the present invention is: use the quartz membrane to collect particulate matter samples, first heat the quartz membrane step by step in the non-oxidizing environment of He gas, volatilize the OC in the particulate matter (some OC is carbonized into EC), and then in the carrier gas Add He/O _x and continue to raise the temperature step by step to oxidize EC to escape. OC and EC escaped from the quartz membrane enter the oxidation furnace tube, are converted into CO ₂ through the catalytic oxidation of MnO ₂ , and finally enter the NDIR detector for quantification. During the whole heating process, the laser emitter always emits a beam of laser light, which is transmitted and reflected by the quartz film and reaches the transmitted laser signal detector and the reflected laser signal detector. The transmitted laser light and the reflected laser light weakened with the carbonization of OC at the beginning, and then gradually increased with the oxidative decomposition of EC. When the light intensity returned to the original light intensity, it was considered to have reached the division point of OC and EC, that is, thermal decomposition before this point The carbonaceous component out of the point is OC, and the carbonaceous component after this point is EC.

The technical scheme provided by the invention is:

The patent of the present invention designs an in-situ online collection analyzer for aerosol carbonaceous components, including two parts: a carrier gas system and a sampling-analysis system;

The carrier gas gas path system includes a He main gas path, a He purge gas path, a He/Ox gas path and a He/CH gas path _;

The He main gas route is composed of a He gas cylinder connected in sequence, a first pressure reducing valve, a first mass flow controller and a first three-way solenoid valve;

The He purge gas route is composed of the He gas cylinder gas, the first pressure reducing valve and the second mass flow controller connected in sequence;

The He/Ox gas route is composed of successively connected He/Ox gas cylinders, a second pressure reducing valve, a third mass flow controller, a second three-way solenoid valve and a third three-way solenoid valve;

The He/CH ₄ gas route is composed of He/CH ₄ gas cylinder gas, a third pressure reducing valve, a fourth mass flow controller and a six-way valve connected in sequence;

The first pressure reducing valve is connected to the first mass flow controller and the second mass flow controller through a first three-way joint; the first mass flow controller is connected to the second mass flow controller through a second three-way joint The normally open end of the first three-way solenoid valve is connected with the normally closed end of the second three-way solenoid valve; the normally closed end of the first three-way solenoid valve is connected with the three ports of the six-way valve; The normally open end of the one-way electromagnetic valve is connected with the common end of the third three-way electromagnetic valve; the common end of the second three-way electromagnetic valve is connected with the third mass flow controller and the six-way electromagnetic valve through the third three-way joint. The four ports of the through valve are connected; the two ports of the six-way valve are connected with the five ports, as the quantitative loop of methane internal standard gas; the six ports of the six-way valve are set as the exhaust end of He/CH gas _; The fourth mass flow controller is connected to one port of the six-way valve;

The sampling-analysis gas path system includes a sampling gas path, an analysis-oxidation furnace and an analysis gas path;

The analysis-oxidation furnace includes an analysis-oxidation furnace tube; the analysis-oxidation furnace tube includes an analysis furnace main pipe, an analysis furnace auxiliary tube and an oxidation furnace tube;

The sampling gas circuit includes a cutting head connected in sequence, a volatile organic compound (VOCs) removal pipe, a ball valve, a desorption-oxidation furnace tube, a two-way solenoid valve, a fifth mass flow controller and a sampling pump; In the road, the VOCs removal pipe is connected with the main air inlet of the ball valve; the front end of the air outlet of the ball valve is provided with an air inlet on one side, and the air outlet of the ball valve is connected with the air inlet on the side of the ball valve; The side air inlet of the ball valve is connected with the common end of the first three-way electromagnetic valve; the gas outlet of the ball valve is connected to the main pipe of the analysis-oxidation furnace through the first joint; the main pipe of the two-way electromagnetic valve is The rear end of the air inlet is provided with an air inlet on one side, and the main air inlet of the two-way solenoid valve communicates with the side air inlet of the two-way electromagnetic valve; the main air inlet of the two-way electromagnetic valve passes through The second joint is connected with the desorption furnace auxiliary pipe of the desorption-oxidation furnace tube; the side air inlet of the two-way solenoid valve is connected with the second mass flow controller; the gas outlet of the two-way valve is connected with the The fifth mass flow controller is connected;

The analysis gas path includes the analysis-oxidation furnace tube of the analysis-oxidation furnace connected in sequence, the fourth three-way solenoid valve, a non-dispersive infrared spectrum (NDIR) detector and a flow meter;

A reflection laser correction system and a transmission laser correction system are arranged inside the first joint and the second joint; the outlet of the oxidation furnace tube of the analysis-oxidation furnace tube passes through the third joint and the fourth three-way solenoid valve The common end is connected; the normally closed end of the fourth three-way solenoid valve is connected with the normally closed end of the third three-way solenoid valve; the normally open end of the fourth three-way solenoid valve is connected with the inlet port of the NDIR detector ; The outlet port of the NDIR detector is connected to the inlet port of the flowmeter; the outlet port of the flowmeter is set as the tail gas emptying port.

For the above-mentioned aerosol carbonaceous component in-situ online collection analyzer, further, in the carrier gas path system and the sampling-analysis gas path system, the cylinder gas, pressure reducing valve, mass flow controller, sampling The pipelines of cutting head, VOCs removal tube and ball valve are made of stainless steel or copper tubes; the rest of the air paths are made of stainless steel tubes, copper tubes, silicone rubber tubes or polytetrafluoroethylene tubes.

For the above-mentioned aerosol carbonaceous component in-situ online collection analyzer, further, the analysis-oxidation furnace tube also includes a first branch pipe, a second branch pipe and a set of sampling pipes in the main pipe of the analysis furnace, each The axes of the pipe fittings are on the same plane; the analysis-oxidation furnace also includes a shell, an electric furnace wire and a K-type thermocouple; the K-type thermocouple includes a first temperature-measuring K-type thermocouple and a second temperature-measuring K-type thermocouple ; The analysis-oxidation furnace tube is placed in the shell; the middle part of the oxidation furnace tube is filled with an analytically pure grade manganese dioxide catalyst;

The sample injection pipe is fixedly connected with the main pipe of the analysis furnace through the fourth joint; the main pipe of the analysis furnace and the secondary pipe of the analysis furnace are in a straight line, and a quartz porous plate is fired in the middle of the connection, and the sample injection A quartz membrane is placed between the tube and the porous quartz plate; the analysis-oxidation furnace tube is wrapped with an electric furnace wire at the position corresponding to the quartz porous plate; The oxidation furnace pipe and the first branch pipe are perpendicular to the straight line where the analytical furnace main pipe is located, and both are located on both sides of the straight line; the front end of the first branch pipe is sealed, and the first temperature measuring pipe is inserted into it. K-type thermocouple, and fixed by the fifth joint, the top of the first temperature-measuring K-type thermocouple is in contact with the front end of the first branch pipe; the second branch pipe is arranged in the middle part of the oxidation furnace tube close to the analysis One side of the furnace main pipe, and perpendicular to the oxidation furnace tube, the front end of the second branch tube is not sealed; the second temperature-measuring K-type thermocouple is placed outside the oxidation furnace tube, and the second temperature-measuring K-type thermocouple The front end of the couple contacts the outer wall of the oxidation furnace tube, and the oxidation furnace tube and the second temperature measuring K-type thermocouple are wrapped in another electric furnace wire; the gas outlet of the second branch pipe is connected to the second branch pipe through the sixth joint The normally open end of the third three-way solenoid valve mentioned above is connected.

The casing of the above-mentioned analysis-oxidation furnace is an aluminum plate, and there is a layer of insulation board close to the inner wall of the casing. A part of the insulation board divides the furnace into two parts: the analysis chamber and the oxidation chamber: the main pipe of the analysis furnace, and the auxiliary chamber of the analysis furnace. The pipe and the first branch pipe are located in the analysis chamber; the oxidation furnace pipe and the second branch pipe are located in the oxidation chamber; the insulation board is made of mullite material; the inside of the oxidation chamber is filled with ceramics Fiber cotton insulation material.

The analysis-oxidation furnace is provided with a fan placed on one side near the main pipe of the analysis furnace, and the position of the air outlet of the fan corresponds to the position of the quartz porous plate in the analysis chamber; the position of the air outlet corresponding to the shell and the insulation board is Empty; the upper part of the shell is provided with a ventilation pipe, the connection between the ventilation pipe and the shell is located directly above the quartz porous plate, and the corresponding connection between the shell and the insulation board is hollowed out; the ventilation The outlet of the tube is set outside the in-situ online collection analyzer of the aerosol carbonaceous components.

In the analysis-oxidation furnace, the working voltage of the electric furnace wire is 220V, the power is 1500W, and the outside of the electric furnace wire is covered with a quartz fiber sleeve. The electric furnace wire is controlled by proportional differential integral combined with pulse width modulation method.

Each part of the analysis-oxidation furnace tube is a high-temperature-resistant quartz material. The outer diameter of the main pipe of the analysis furnace tube is 20 mm, the outer diameter of the secondary tube of the analysis furnace tube is 10 mm, and the outer diameter of the middle part of the oxidation furnace tube is 13 mm, the outer diameter of the first branch pipe and the second branch pipe is 6.35 mm, and the outer diameter of the injection tube is 16 mm.

In the analysis-oxidation furnace, the quartz porous plate is a circular quartz plate evenly distributed with six small circular holes, the inner diameter of the circular quartz plate is 6 mm, the outer diameter is 17 mm, and the diameter of the small circular holes is 2 mm; the quartz membrane is in contact with the quartz porous plate, and the quartz porous plate plays a supporting role for the quartz membrane.

In the analysis-oxidation furnace, further, a reflection laser correction system and a transmission laser correction system are arranged inside the first joint and the second joint;

The reflected laser correction system includes a laser emitter, a quartz plate, a first filter and a reflected laser signal detector; the transmitted laser correction system includes the laser emitter, the quartz plate, a second filter chip and transmission laser signal detector;

The reflective laser correction system is located inside the first joint: a laser emitter groove for inserting and fixing the laser emitter is arranged on the outside of the first joint, and the center line of the laser emitter groove is in line with the The center lines of the first joint coincide; the quartz plate is sealed and fixed in the groove of the laser emitter through an O-ring, and placed close to the front end of the laser emitter; the front end of the groove of the laser emitter is also set A first air groove communicated with the sampling tube; a second air groove perpendicular to the first air groove is arranged on the side of the first joint, and the first air groove and the second air groove are communicated with each other; the inner side of the first joint is also provided with a reflected laser signal detector groove for inserting and fixing the reflected laser signal detector; the first optical filter is sealed and fixed on the In the groove of the reflected laser signal detector, and placed close to the front end of the reflected laser signal detector; the transmitted laser correction system is located inside the second joint: a set for inserting and fixing is provided on the outside of the second joint The transmission laser signal detector groove of the transmission laser signal detector, its centerline coincides with the centerline of the second joint; the second optical filter is sealed and fixed in the transmission laser signal detector groove by an O ring In the groove, and placed close to the front end of the transmitted laser signal detector; the front end of the groove of the transmitted laser signal detector is also provided with a third air groove communicated with the secondary pipe; the side of the second joint is also provided A fourth air groove perpendicular to the third air groove, the third air groove and the fourth air groove communicate with each other.

The above-mentioned laser emitter adopts a point-shaped red laser emitter whose central emission wavelength is 660nm, power is 50mW, and emission frequency is 1Hz; the optical filter adopts an optical filter whose central wavelength is 660nm and bandwidth is 8nm; the transmission The laser signal detector and reflected laser signal detector are photodiodes capable of producing highly sensitive linear responses to 660nm laser light.

In the above-mentioned in-situ on-line collection and analyzer of aerosol carbonaceous components, the first and second joints are aluminum joints with inner O-rings; the third, fifth, and sixth joints are stainless steel joints with inner O-rings; The four joints are plastic joints with O-rings inside.

The aerosol carbonaceous component in-situ online collection analyzer provided by the present invention realizes the automatic control of the collection analyzer through the combination of the control circuit, single-chip microcomputer and industrial computer when it is working; the control circuit is the collection analyzer All hardware in the system provides working voltage and DO, AO control signals, and is responsible for collecting and amplifying corresponding detection signals at the same time, so that the single-chip microcomputer performs A/D conversion, and then is read and identified by the industrial computer; the NDIR detection The device communicates directly with the industrial computer. The computer software written in the computer language can flexibly automatically control the acquisition analyzer and automatically analyze the data; the computer software includes two parts: a control program and a data processing program; a state display window is nested in the control program , parameter setting window, separate control window for each valve body, and calibration curve window; the status display window can display the real-time operating status of the acquisition analyzer and the parameters of temperature, flow, laser, and NDIR, and the parameter setting window can perform The setting of each carrier gas flow rate, sampling time and flow rate, temperature rise program, temperature control PID parameters, and _CO2 delay time, the separate control window of each valve body can control the opening and closing of each valve body, so as to check the state and troubleshoot; The calibration curve window can automatically generate a standard curve according to the input multi-point calibration results; the data processing program can obtain the concentration of OC and EC of the sample according to the standard curve.

The present invention also provides an online collection and analysis method using the above-mentioned aerosol carbonaceous component in-situ online collection analyzer, which sequentially includes a sampling stage, a purging stage, an OC analysis stage, an EC analysis stage, a methane quantitative stage, a methane calibration stage, and an instrument Cooling and standby phase; specifically includes the following processes:

1) Sampling stage: collect air samples through the sampling gas path;

The sampling time and sampling flow rate can be set by the user according to the air pollution situation;

After the sampling stage begins, the ball valve 212, pump 215, two-way solenoid valve 213, and fan 24 of the instrument (the in-situ on-line collection analyzer for aerosol carbonaceous components) are opened, and the air enters the cutting head 210, VOCs removal pipe 211, ball valve 212, and enter the main pipe 2210 of the desorption furnace through the joint 220; when the air sample passes through the quartz membrane 2218, the particulate matter is trapped on the quartz membrane 2218; at the same time, the He main gas passes through the mass flow controller 112, The side air inlets of the three-way solenoid valve 113 and the ball valve 212 enter the main pipe 2210 of the analytical furnace; the He/O _x carrier gas passes through the mass flow controller 132, the three-way solenoid valve 133, the three-way solenoid valve 134, the three-way solenoid valve 230, Enter the oxidation furnace tube 2212; He main gas, He/O _x carrier gas and sampling air are mixed together, pass through the desorption furnace auxiliary tube 2211, two-way solenoid valve 213, mass flow controller 214, and sampling pump 215, and then are discharged. During this process, the He main gas and the He/O _x carrier gas ensure that the analysis-oxidation furnace tube 221 is in a dry environment, preventing water vapor from entering the oxidation furnace tube 2212 and causing catalyst poisoning; all three-way solenoid valves and six-way valves are kept de-energized Status: The C (common) end of the three-way solenoid valve body is connected to the NO (normally open) end, and the 12, 34, and 56 ports of the six-way valve are connected; the oxidation furnace is kept at 500 ° C; the sampling time and sampling flow rate can be adjusted according to Air pollution conditions are set by the user.

2) Purging process: He main gas, He purge gas and He/O _x carrier gas are mixed together, and the purging process lasts for a period of time;

After the purge phase starts, the instrument ball valve 212, pump 215, two-way solenoid valve 213, and fan 24 are closed, and the He main flow path remains unchanged; The He/O _x carrier gas enters the branch pipe 2215 through the mass flow controller 132, the three-way solenoid valve 133, and the three-way solenoid valve 134; the He main gas, the He purge gas and the He/O _x carrier gas The gases are mixed together through the oxidation furnace tube 2212, the three-way solenoid valve 230, the NDIR detector 231, the flow meter 232 and are discharged. The purging process lasts for 200s to ensure that the residual gas in the furnace tube is fully blown out and the quartz film 2218 is in a non-oxidizing environment. During this process, the desorption furnace was kept at 10°C, and the oxidation furnace was heated rapidly and kept at 870°C. In the last 30s of the purge phase, the software began to record the data of each parameter and start drawing images.

3) OC analysis process: OC is gradually thermally decomposed and volatilized in the oxygen-free environment of He gas; it is converted into CO ₂ and quantified by NDIR detector;

OC analysis process: After the OC analysis process starts, the state of each valve body and mass flow controller remains unchanged, that is, the flow rate of each carrier gas and the flow direction of the gas path remain unchanged. The OC on the quartz membrane 2218 is gradually thermally decomposed in the heating program selected by the user, and enters the oxidation furnace tube 2212 to be converted into CO ₂ and is quantified by the NDIR detector 231; the oxidation furnace is maintained at 870°C.

4) EC analysis process: EC is oxidized in an oxidizing environment, further converted into CO ₂ and quantified by an NDIR detector;

After the EC analysis process starts, the three-way solenoid valves 113, 133 and 134 are opened, that is, the C terminal and the NC terminal of the valve body are connected, and the other three-way solenoid valves remain in a de-energized state. The He purge gas path remains unchanged, the He main gas enters the port 4 of the six-way valve 143 through the mass flow controller 112 and the three-way solenoid valve 133; the He/O _x carrier gas passes through the mass flow controller 132 and the three-way connector 153 is mixed with the main gas of He, and then enters the main gas of the desorption furnace 2210 through the six-way valve 143 and the three-way solenoid valve 113; during this process, the quartz film 2218 is in an oxidizing environment, and the original EC and a part of OC carbonized on it are in the It is oxidized in the heating program, enters the oxidation furnace tube 2212 and is further converted into CO ₂ and is quantified by the NDIR detector 231; the oxidation furnace 2212 is kept at 870°C.

5) Methane quantitative process: inject He/CH ₄ internal standard gas into the quantitative loop;

After the methane quantitative process starts, the state of each valve body is consistent with that of the previous stage, and the gas paths and flow rates of the He main gas, He purge gas and He/O _x carrier gas remain unchanged; the mass flow controller 142 is opened, and the He/CH ₄ The internal standard gas enters the pipeline (quantitative loop) between the 2 and 5 ports of the six-way valve through the mass flow controller 142 and the 1st port of the 6-way valve. This process is maintained for 50s, and the He/CH ₄ internal standard gas fills the quantitative loop Finally, the excess He/CH ₄ internal standard gas is discharged through port 6 of the six-way valve. During this process, the fan 24 is turned on to cool down the desorption furnace tube 2210; the oxidation furnace tube 2212 is kept at 870°C.

6) Methane calibration process: He main gas and He/O _x carrier gas mixed gas blow out and oxidize the original He/CH ₄ internal standard gas in the quantitative loop, and convert it into CO ₂ to be quantified by the NDIR detector;

After the methane calibration process starts, the state of each three-way solenoid valve body is consistent with the previous stage, and the six-way valve 143 is opened, that is, ports 16, 23, and 45 of the valve body are connected; the mass flow controller 142 is closed, and the He/ CH ₄ flow is 0. The He _purge gas path remains unchanged; the He main gas enters the six-way valve 143 through the mass flow controller 112 and the three-way solenoid valve 133; The main gas is mixed, the mixed gas of He main gas and He/O _x carrier gas enters the six-way valve 143, blows the original He/CH ₄ internal standard gas in the quantitative loop into the three-way solenoid valve 113, and finally enters the main pipe of the desorption furnace 2210, And converted to CO ₂ in the oxidation furnace tube 2212 and quantified by the NDIR detector 231. This process lasts for 15 seconds, during which the fan 24 is kept on, and the temperature of the desorption furnace 2210 is continued to be lowered; the oxidation furnace 2212 is kept at 870°C.

7) Cooling process: the instrument cools down, automatically stops the analysis stage, saves the data and curves, and enters the standby process;

After the cooling process starts, the state of each three-way solenoid valve body and mass flow controller is consistent with the EC process, and the six-way valve is closed; the fan 24 is kept open, and the temperature of the desorption furnace tube 2210 is continued; the oxidation furnace tube 2212 is maintained at 870°C. When the temperature of the analytical furnace tube 2210 drops below 75°C, the instrument automatically stops the analysis phase, saves the data and curves, enters the standby process, and waits for the next sampling-analysis.

8) Standby process: waiting for the next sampling-analysis.

After the cooling process is over, the instrument enters the standby process, and the state of each valve body and mass flow controller is consistent with the purging process, that is, the flow rate and flow direction of each carrier gas are consistent with the purging process. The fan remains on, the temperature of the desorption furnace is set at 10°C, and the temperature of the oxidation furnace is lowered to 500°C.

Compared with prior art, the beneficial effect of the present invention is:

The invention provides an in-situ online collection and analysis instrument for aerosol carbonaceous components. No other structures except the quartz film are set in the laser light path, which ensures the accuracy of the light path; Calibrate at the same point to comprehensively reflect the change of film blackness; the design of the valve body greatly reduces the quantitative error of the methane internal standard gas, ensures the stability of the internal standard gas, and improves the accuracy of EC and OC measurement results; the gas circuit design ensures The composition of the carrier gas in the system remains unchanged throughout the analysis period, which ensures the stability of the system background. The present invention adopts the above technical solutions, specifically, has the following advantages:

1. There is no structure other than the quartz film in the laser light path. The laser light emitted by the laser light source is reflected and transmitted by the quartz film and directly reaches the reflection and transmission laser detector, which effectively ensures the accuracy of the laser received by the detector. Make the judgment of split point more accurate;

2. The reflective laser photoelectric detection system and the transmitted laser photoelectric detection system are used comprehensively, which can reflect the blackness change on the surface and thickness direction of the quartz film at the same time, which is convenient for comprehensively judging the split point, and the time interval between the OC/EC split points of the transmitted laser and reflected laser It can further reflect the rapidity of system temperature rise;

3. Use the six-way valve to control the quantification and injection of the methane internal standard gas, which greatly reduces the instability of the internal standard gas volume caused by the excessive dead volume of the three-way solenoid valve body, and improves the EC and OC measurement results accuracy;

4. Self-designed gas circuit system and reasonable arrangements for the use of each gas, not only efficiently saves the amount of carrier gas used, but also achieves the consistency of carrier gas in the entire work process, improving the furnace cavity in the analysis stage. The stability of the internal gas background and gas pressure; and the carrier gas passes around the laser transmitter, transmission and reflection laser detectors, which takes away part of the heat generated by the laser transmitter, transmission and reflection laser detectors, which is conducive to laser detection system stability;

5. The temperature control of the furnace wire adopts the proportional differential integral algorithm combined with the pulse width modulation technology, which makes continuous heating into pulse heating, increases the service life of the furnace wire, and is conducive to the long-term stable operation of the instrument.

The invention has strong practicability, low operating cost and convenient management, is suitable for laboratory research and the use of environmental protection automatic monitoring stations all over the country, and can obtain more real and accurate data of atmospheric aerosol carbonaceous components.

By using the technical solution provided by the invention, more accurate monitoring data can be obtained, and support can be provided for a clearer understanding of the current situation of aerosol pollution, control of air pollution and improvement of air quality.

Description of drawings

Fig. 1 is a structural diagram of an in-situ online collection analyzer for aerosol carbonaceous components provided by an embodiment of the present invention;

Fig. 2 is a structural diagram of the analysis-oxidation furnace provided by the embodiment of the present invention;

In Figures 1 to 2, 1—carrier gas circuit system; 2—sampling-analysis gas circuit system; 11—He main gas circuit; 12—He purge gas circuit; 13—He/O _x gas circuit ; 14—He/CH ₄ gas circuit; 110—He gas cylinder gas 110; 111—the first pressure reducing valve; 112—the first mass flow controller; 113—the first three-way solenoid valve; 122—the second mass Flow controller; 130—He/O _x gas cylinder gas; 131—second pressure reducing valve; 132—third mass flow controller; 133—second three-way solenoid valve; 134—third three-way solenoid valve; 140 —He/CH ₄ gas cylinder gas; 141—third pressure reducing valve; 142—fourth mass flow controller; 143—six-way valve; 151—first three-way joint; 152—second three-way joint; 153— The third tee joint; 21—sampling gas path; 22—analysis-oxidation furnace; 23—analysis gas path; 210—cutting head; 211—VOCs removal pipe; 212—ball valve; 213—two-way solenoid valve; 214—the first Five mass flow controllers; 215—sampling pump; 220—first joint; 221—analysis-oxidation furnace tube; 222—second joint; 223—third joint; 224—electric furnace wire; 225—K type thermocouple; 226 —shell; 227—fourth joint; 228—fifth joint; 229—sixth joint; 230—fourth three-way solenoid valve; 231—NDIR detector; 232—flow meter; Furnace auxiliary tube; 2212—analysis-oxidation furnace tube of oxidation furnace tube; 2214—first branch pipe; 2215—second branch pipe; 2216—injection tube; 2217—quartz porous plate; 2218—quartz membrane;

Fig. 3 is a structural diagram of a laser calibration system provided by an embodiment of the present invention;

Fig. 4 is a structural diagram of a reflected laser correction system provided by an embodiment of the present invention;

Fig. 5 is a structural diagram of a transmission laser correction system (excluding a laser emitter) provided by an embodiment of the present invention;

3-5, 30—reflected laser correction system; 31—transmitted laser correction system; 301—laser transmitter; 302—quartz plate; 303—first optical filter; 304—reflected laser signal detector; 310— The second optical filter; 311—transmitted laser signal detector; 305—laser emitter groove; 306—first air groove; 307—second air groove; 308—reflected laser signal detector groove; 312—transmitted laser Signal detector groove; 313—the third air groove; 314—the fourth air groove.

Fig. 6 is a flow chart of each stage of the in-situ online collection and analysis of aerosol carbonaceous components provided by the embodiment of the present invention.

Detailed ways

Below in conjunction with accompanying drawing, further describe the present invention through embodiment, but do not limit the scope of the present invention in any way.

The invention provides an in-situ online collection and analysis instrument for aerosol carbonaceous components. No other structures except the quartz film are set in the laser light path, which ensures the accuracy of the light path; Calibrate at the same point to comprehensively reflect the change of film blackness; the design of the valve body greatly reduces the quantitative error of the methane internal standard gas, ensures the stability of the internal standard gas, and improves the accuracy of EC and OC measurement results; the gas circuit design ensures During the analysis stage, the composition of the carrier gas in the system is constant, which ensures the stability of the system background.

As shown in FIG. 1 , the in-situ online collection and analysis instrument for aerosol carbonaceous components provided by the embodiment of the present invention mainly includes two parts: a carrier gas circuit system 1 and a sampling-analysis gas circuit system 2 . The carrier gas gas path system 1 includes a He main gas path 11, a He purge gas path 12, a He/O _x gas path 13 and a He/CH ₄ gas path 14, wherein: the He main gas path 11 consists of The connected He gas cylinder gas 110, the pressure reducing valve 111, the mass flow controller 112, and the three-way solenoid valve 113 are composed of the He gas main gas circuit 11, which is mainly used to control the main carrier gas He gas; the He purge gas route is connected in sequence _Composed of He gas cylinder 110, pressure reducing valve 111, and mass flow controller 122, it _is mainly used for purging and supplementing bypass gas; 130, pressure reducing valve 131, mass flow controller 132, three-way solenoid valve 133, _{three -} way solenoid valve 134; 141, a mass flow controller 142, and a six-way valve 143 are formed. The pressure reducing valve 111 is connected with the mass flow controller 112 and the mass flow controller 122 through the three-way joint 151; The closed end is connected; the normally closed end of the three-way solenoid valve 113 is connected with the 3 port of the six-way valve; the normally open end of the three-way solenoid valve 133 is connected with the common end of the three-way solenoid valve 134; the common end of the three-way solenoid valve 133 is connected through The three-way joint 153 is connected with the 4 ports of the mass flow controller 132 and the six-way valve 143; the mass flow controller 142 is connected with the 1 port of the six-way valve 143; the 2 ports of the six-way valve 143 are connected with the 5 ports as Quantitative loop of methane internal standard gas; port 6 of six-way valve 143 is set as the exhaust end of He/CH ₄ gas.

In the above-mentioned embodiment, the He gas used in the carrier gas circuit system ₁ is 99.99% high-purity He gas, the He/O _x gas is a mixed gas with O volume concentration of ₁₀ %, and He/ _CH is CH volume by volume Concentration of 5% mixture.

In the above-mentioned embodiments, the pipelines connecting cylinder gas, pressure reducing valve and mass flow controller in the carrier gas circuit system 1 can use stainless steel tubes or copper tubes; the rest of the gas channels can use stainless steel tubes, copper tubes, silicon rubber tubes or PTFE tubing.

As shown in Figures 1 and 2, the sampling-analysis gas path system 2 of the present invention includes a sampling gas path 21, an analysis-oxidation furnace 22, and an analysis gas path 23, wherein: the sampling gas path 21 includes a cutting head 210, which is connected in sequence, VOCs removal pipe 211, ball valve 212, analysis-oxidation furnace pipe 221, two-way solenoid valve 213, mass flow controller 214, sampling pump 215; VOCs removal pipe 211 is connected to the main air inlet of ball valve 212; the front end of the air outlet of ball valve 212 One side air inlet is set, the air outlet of the ball valve 212 is connected with the side air inlet, and the side air inlet is connected with the common end of the three-way solenoid valve 113; the air outlet of the ball valve 212 is connected with the analysis-oxidation furnace pipe 221 The analytical furnace main pipe 2210 is connected; the rear end of the main air inlet of the two-way solenoid valve 213 is provided with a side air inlet, the main air inlet and the side air inlet are connected, and the main air inlet is connected to the auxiliary pipe of the analytical furnace through the joint 222 2211; the side inlet of the two-way solenoid valve 213 is connected to the mass flow controller 122; the gas outlet of the two-way solenoid valve 213 is connected to the gas inlet of the mass flow controller 214, and the gas outlet of the mass flow controller 214 is connected to the sampling port Pump 215 is connected. The analysis gas path 23 includes the analysis-oxidation furnace pipe 221, three-way electromagnetic valve 230, NDIR detector 231, flowmeter 232 connected in sequence, and the outlet of the oxidation furnace pipe 2212 of the analysis-oxidation furnace pipe 221 is connected with the three-way electromagnetic valve through the joint 223. The common end of the valve 230 is connected; the normally closed end of the three-way solenoid valve 230 is connected with the normally closed end of the three-way solenoid valve 134; the normally open end of the three-way solenoid valve 230 is connected with the inlet port of the NDIR detector 231; the NDIR detector 231 The outlet end of the flow meter is connected to the inlet end of the flow meter 232; the outlet end of the flow meter 232 is set as the exhaust gas end. The analysis-oxidation furnace 22 includes an analysis-oxidation furnace tube 221 , an electric furnace wire 224 , a K-type thermocouple 225 , and a casing 226 . The analysis-oxidation furnace pipe 221 is placed in the shell 226; the analysis-oxidation furnace pipe 221 includes the main pipe 2210 of the analysis furnace, the auxiliary pipe 2211 of the analysis furnace, the first branch pipe 2214 of the oxidation furnace pipe 2212, the second branch pipe 2215 and a set of analysis The axis lines of the sampling pipes 2216 in the furnace main pipe 2210 are located on the same plane. The sample injection pipe 2216 is fixedly connected with the main pipe 2210 of the analysis furnace through the joint 227; the main pipe 2210 of the analysis furnace and the auxiliary pipe 2211 of the analysis furnace are in a straight line, and a quartz porous plate 2217 is fired in the middle of the joint, and the analysis-oxidation furnace pipe 221 is made of quartz. The position corresponding to the perforated plate 2217 is wrapped with the electric furnace wire 224, and a quartz membrane 2218 is placed between the sampling tube 2216 and the quartz perforated plate 2217; The straight line where the furnace main pipe 2210 is located is vertical and located on both sides of the straight line; the front end of the first branch pipe 2214 is sealed, and a temperature-measuring K-type thermocouple 225 is inserted inside, and fixed by a joint 228. The top of the K-type thermocouple 225 is connected to the first The front end of the branch pipe 2214 is in contact; the second branch pipe 2215 is arranged on the side of the middle part of the oxidation furnace tube 2212 close to the main pipe 2210 of the analytic furnace, and is perpendicular to the oxidation furnace tube 2212, and the front end of the second branch pipe 2215 is not sealed; Temperature K-type thermocouple 225, the front end of K-type thermocouple 225 contacts the outer wall of the middle part of the oxidation furnace tube 2212; the oxidation furnace tube 2212 and the temperature-measuring K-type thermocouple 225 are wrapped in another electric furnace wire 224; the second branch tube The air outlet of 2215 is connected with the normally open end of the three-way solenoid valve 134 through the joint 229 .

In the above embodiments, the pipelines connecting the sampling and cutting head 210, the VOCs removal tube 211, and the ball valve 212 can use stainless steel tubes or copper tubes; the rest of the gas channels can use stainless steel tubes, copper tubes, silicon rubber tubes or polytetrafluoroethylene tubes.

In the above embodiment, the joints 220, 222 are aluminum joints with O-rings inside; the joints 223, 225, 229 are stainless steel joints with O-rings inside; joint 227 is a plastic joint with O-rings inside.

In the above embodiment, the middle part of the oxidation furnace tube 2212 is filled with an analytically pure manganese dioxide catalyst.

In the above-mentioned embodiment, the shell 226 is an aluminum plate with a thickness of 10 mm, and there is a layer of insulation board close to the inner wall of the shell 226, and a part of the heat preservation plate separates the furnace into two parts: the analysis chamber and the oxidation chamber: the analysis furnace tube supervisor 2210, the analysis furnace auxiliary The pipe 221 and the first branch pipe 2214 are located in the analysis chamber; the oxidation furnace pipe 2212 and the second branch pipe 2215 are located in the oxidation chamber; the insulation board is made of mullite material; the inner space of the oxidation chamber is filled with the insulation material of ceramic fiber cotton.

In the above-mentioned embodiment, the K-type temperature-measuring thermocouple 225 is connected to the temperature controller, and the temperature controller controls the heating of the electric furnace wire 224 through a solid-state relay; The heating control of the casing and the electric furnace wire 224 adopts a proportional differential integral algorithm combined with a pulse width modulation technique.

In the above embodiment, each part of the analysis furnace tube 221 is made of high temperature resistant quartz material, the outer diameter of the main tube 2210 is 20 mm, the outer diameter of the auxiliary tube 2211 is 10 mm, the outer diameter of the middle part of the oxidation furnace tube 2212 is 13 mm, and the first branch tube 2214 and the second branch pipe 2215 have an outer diameter of 6.35 millimeters, and the outer diameter of the sampling tube 2216 is 16 millimeters.

In the above embodiment, in order to achieve a larger sampling flow rate, ensure that the collected samples can be evenly distributed on the quartz membrane 2218, and ensure that the quartz membrane 2218 can be heated quickly and evenly, the connection between the main pipe 2210 of the desorption furnace and the auxiliary pipe 2211 of the desorption furnace is burnt A porous quartz plate 2217 is made and fixed; a quartz membrane 2218 is placed between the sampling tube 2216 and the quartz porous plate 2217, and the porous quartz plate 2217 and the quartz membrane 2218 are closely attached; the quartz porous plate 2217 is a uniform distribution with 6 small round holes A ring quartz plate, the inner diameter of the ring quartz plate is 6 mm, the outer diameter is 17 mm, and the diameter of the small circular hole is 2 mm.

In the above embodiment, the analysis-oxidation furnace 22 is provided with a fan 24 placed on one side by the side of the main pipe 2210 of the analysis furnace, and its air outlet position corresponds to the position of the quartz porous plate 2217 in the analysis chamber; the corresponding air outlet position of the shell 226 and the insulation board is Hollowed out. A ventilation pipe 25 is arranged on the upper part of the casing 226, and the joint between the ventilation pipe 25 and the casing 226 is located directly above the quartz porous plate 2217, and the position corresponding to the connection between the casing 2217 and the heat preservation plate is hollowed out; the outlet of the ventilation pipe 25 is set outside the instrument.

As shown in Fig. 3, Fig. 4 and Fig. 5, a reflection laser correction system 30 and a transmission laser correction system 31 are arranged inside the first joint 220 and the second joint 222, and the reflection laser correction system 30 includes a laser transmitter 301, quartz sheet 302, a first optical filter 303 and a reflected laser signal detector 304; the transmitted laser correction system 31 includes a laser emitter 301, a second optical filter 310 and a transmitted laser signal detector 311. The reflection laser correction system 30 is located inside the first joint 220: a laser transmitter groove 305 for inserting and fixing the laser transmitter 301 is arranged on the outside of the first joint 220, and is coaxial with the first joint 220; the quartz plate 302 passes through The O-ring is sealed and fixed in the groove 305 of the laser emitter, and placed close to the front end of the laser emitter 301; the front end of the groove 305 of the laser emitter in the first joint 220 is also provided with a first air tank communicated with the sampling tube 2216 306; the side of the first joint 220 is also provided with a second air groove 307 perpendicular to the first air groove 306, and the first air groove 306 and the second air groove 307 communicate with each other; the inside of the first joint 220 is also provided with a Insert and fix the reflected laser signal detector groove 308 of the reflected laser signal detector 304; the first optical filter 303 is sealed and fixed in the reflected laser signal detector groove 308 through an O ring, and is close to the reflected laser signal detector 308 front placement. The transmission laser calibration system 31 is located inside the second joint 222: a transmission laser signal detector groove 312 for inserting and fixing the transmission laser signal detector 311 is arranged on the outside of the second joint 222, which is coaxial with the second joint 222; The second optical filter 310 is sealed and fixed in the transmission laser signal detector groove 312 through an O ring, and is placed close to the front end of the transmission laser signal detector 311; the front end of the transmission laser photodetector groove 312 is also provided with a The third air groove 313 communicated with the auxiliary pipe 2211; a fourth air groove 314 perpendicular to the third air groove 313 is also provided on the side of the second joint 222, and the third air groove 313 and the fourth air groove 314 communicate with each other .

In the above-described embodiment, the laser transmitter 301 adopts a point-shaped red laser transmitter with a central emission wavelength of 660nm, a power of 50mW, and an emission frequency of 1Hz. The emitted light is concentrated and the divergence angle is small; the first filter 303, the second filter Sheet 310 is a filter with a central wavelength of 660nm and a bandwidth of 8nm, which can effectively filter out stray light in other bands and avoid interference; the reflected laser signal detector 309 and the transmitted laser signal detector 311 are photodiodes, which can generate 660nm laser light. Highly sensitive linear response.

The present invention realizes the automatic control of the whole instrument through the combination of the control circuit 4, the single-chip microcomputer 5 and the industrial computer 6. The control circuit 4 provides working voltage and DO and AO control signals for all hardware in the whole instrument, and is responsible for collecting and amplifying the corresponding detection signals for A/D conversion by the single-chip microcomputer 5, and then read and identify by the industrial computer 6. The NDIR detector 231 communicates directly with the industrial computer 6 .

In the above-described embodiment, the single-chip microcomputer 5 can realize the laser value, the analysis furnace temperature value, the oxidation furnace temperature value, the flow meter flow rate, sampling and each gas path (He main gas, He purging carrier gas, He main gas, He purge carrier gas, etc.) He/Ox carrier gas and He/CH ₄ internal standard gas) flow signal collection, and display on the program interface of the industrial computer; at the same time, it can also realize the mass flow controller, three-way solenoid valve, two-way solenoid valve, ball valve , Real-time control of electric furnace wire, fan, sampling pump and laser transmitter. The invention uses computer language to write software, including two parts of control program and data processing program, which can flexibly automatically control the acquisition analyzer and automatically analyze the data; there are state display windows and parameter setting windows nested in the control program , Individual control window for each valve body, calibration curve window: the status display window can display the real-time operating status of the acquisition analyzer and the parameters of temperature, flow, laser, and NDIR, and the setting window can perform various carrier gas flow rates, sampling time and flow rates, Setting of temperature rise program, temperature control PID parameters, _CO2 delay time, individual control window of each valve body can control the opening and closing of each valve body, so as to facilitate status inspection and troubleshooting; calibration curve window can automatically Generate a standard curve; the data processing program can obtain the concentration of OC and EC of the sample according to the standard curve.

As shown in Figure 6, the specific work process of the present invention is as follows:

1) Sampling phase: After the sampling phase begins, the ball valve 212, pump 215, two-way solenoid valve 213, and fan 24 of the instrument are turned on, and the air enters the cutting head 210, VOCs removal pipe 211, and ball valve 212 sequentially under the action of the pump 215, and Enter the main pipe 2210 of the desorption furnace through the joint 220; when the air sample passes through the quartz membrane 2218, the particulate matter is trapped on the quartz membrane 2218; at the same time, the He main gas passes through the mass flow controller 112, the three-way solenoid valve 113, and the ball valve 212. The side air inlet enters the main pipe of the desorption furnace 2210; the He/O _x carrier gas enters the oxidation furnace pipe 2212 through the mass flow controller 132, the three-way solenoid valve 133, the three-way solenoid valve 134, and the three-way solenoid valve 230; , He/O _x carrier gas and sampled air are mixed together and passed through the auxiliary pipe 2211 of the desorption furnace, the two-way solenoid valve 213, the mass flow controller 214, and the sampling pump 215, and then discharged. During this process, the He main gas and the He/O _x carrier gas ensure that the analysis-oxidation furnace tube 221 is in a dry environment, preventing water vapor from entering the oxidation furnace tube 2212 and causing catalyst poisoning; all three-way solenoid valves and six-way valves are kept de-energized Status: The C (common) end of the three-way solenoid valve body is connected to the NO (normally open) end, and the 12, 34, and 56 ports of the six-way valve are connected; the oxidation furnace is kept at 500 ° C; the sampling time and sampling flow rate can be adjusted according to Air pollution conditions are set by the user.

2) Purge process: After the purge phase starts, the instrument ball valve 212, pump 215, two-way solenoid valve 213, and fan 24 are closed, and the He main flow path remains unchanged; the He purge gas passes through the mass flow controller 122, the two-way electromagnetic valve The side air inlet of the valve 213 enters the auxiliary pipe 2211 of the desorption furnace; the He/O _x carrier gas enters the branch pipe 2215 through the mass flow controller 132, the three-way solenoid valve 133, and the three-way solenoid valve 134; the He main gas and He purge gas Mixed with the He/O _x carrier gas, it passes through the oxidation furnace tube 2212, the three-way solenoid valve 230, the NDIR detector 231, the flow meter 232 and is discharged. The purging process lasts for 200s to ensure that the residual gas in the furnace tube is fully blown out and the quartz film 2218 is in a non-oxidizing environment. During this process, the desorption furnace was kept at 10°C, and the oxidation furnace was heated rapidly and kept at 870°C. In the last 30s of the purge phase, the software began to record the data of each parameter and start drawing images.

3) OC analysis process: After the OC analysis process starts, the state of each valve body and mass flow controller remains unchanged, that is, the flow rate of each carrier gas and the flow direction of the gas path remain unchanged. The OC on the quartz membrane 2218 is gradually thermally decomposed in the heating program selected by the user, and enters the oxidation furnace tube 2212 to be converted into CO ₂ and is quantified by the NDIR detector 231; the oxidation furnace is maintained at 870°C.

4) EC analysis process: After the EC analysis process starts, the three-way solenoid valves 113, 133 and 134 are opened, that is, the C terminal and the NC terminal of the valve body are connected, and the remaining three-way solenoid valves remain in a de-energized state. The He purge gas path remains unchanged, the He main gas enters the port 4 of the six-way valve 143 through the mass flow controller 112 and the three-way solenoid valve 133; the He/O _x carrier gas passes through the mass flow controller 132 and the three-way connector 153 is mixed with the main gas of He, and then enters the main gas of the desorption furnace 2210 through the six-way valve 143 and the three-way solenoid valve 113; during this process, the quartz film 2218 is in an oxidizing environment, and the original EC and a part of OC carbonized on it are in the It is oxidized in the heating program, enters the oxidation furnace tube 2212 and is further converted into CO ₂ and is quantified by the NDIR detector 231; the oxidation furnace 2212 is kept at 870°C.

5) Methane quantitative process: After the methane quantitative process starts, the state of each valve body remains consistent with the previous stage, and the gas paths and flow rates of the He main gas, He purge gas, and He/O _x carrier gas remain unchanged; the mass flow controller 142 is turned on, and the He/CH ₄ internal standard gas enters the pipeline (quantitative loop) between the 2 and 5 ports of the six-way valve through the mass flow controller 142 and the 1 port of the six-way valve. This process is maintained for 50s, and the He/CH ₄ After the internal standard gas fills the quantitative loop, the excess He/CH ₄ internal standard gas is discharged through port 6 of the six-way valve. During this process, the fan 24 is turned on to cool down the desorption furnace tube 2210; the oxidation furnace tube 2212 is kept at 870°C.

6) Methane calibration process: After the methane calibration process starts, the state of each three-way solenoid valve body is consistent with the previous stage, and the six-way valve 143 is opened, that is, ports 16, 23, and 45 of the valve body are connected; mass flow control The device 142 is closed and the He/CH ₄ flow is zero. The He _purge gas path remains unchanged; the He main gas enters the six-way valve 143 through the mass flow controller 112 and the three-way solenoid valve 133; The main gas is mixed, the mixed gas of He main gas and He/O _x carrier gas enters the six-way valve 143, blows the original He/CH ₄ internal standard gas in the quantitative loop into the three-way solenoid valve 113, and finally enters the main pipe of the desorption furnace 2210, And converted to CO ₂ in the oxidation furnace tube 2212 and quantified by the NDIR detector 231. This process lasts for 15 seconds, during which the fan 24 is kept on, and the temperature of the desorption furnace 2210 is continued to be lowered; the oxidation furnace 2212 is kept at 870°C.

7) Cooling process: After the cooling process starts, the state of each three-way electromagnetic valve body and mass flow controller is consistent with the EC process, and the six-way valve is closed; the fan 24 is kept open, and the temperature of the desorption furnace tube 2210 continues to cool; the oxidation furnace tube 2212 Keep at 870°C. When the temperature of the analytical furnace tube 2210 drops below 75°C, the instrument automatically stops the analysis phase, saves the data and curves, enters the standby process, and waits for the next sampling-analysis.

8) Standby process: After the cooling process is over, the instrument enters the standby process, and the state of each valve body and mass flow controller is consistent with the purging process, that is, the flow rate and flow direction of each carrier gas are consistent with the purging process. The fan remains on, the temperature of the desorption furnace is set at 10°C, and the temperature of the oxidation furnace is lowered to 500°C.

It should be noted that the purpose of the disclosed embodiments is to help further understand the present invention, but those skilled in the art can understand that various replacements and modifications are possible without departing from the spirit and scope of the present invention and the appended claims of. Therefore, the present invention should not be limited to the content disclosed in the embodiments, and the protection scope of the present invention is subject to the scope defined in the claims.

Claims (11)

1. An in-situ online collection analyzer for aerosol carbonaceous components, including a carrier gas system and a sampling-analysis gas system; The carrier gas gas path system includes a He main gas path, a He purge gas path, a He/O _x gas path and a He/CH gas path _; The He main gas route is composed of a He gas cylinder connected in sequence, a first pressure reducing valve, a first mass flow controller and a first three-way solenoid valve; The He purge gas route is composed of the He gas cylinder gas, the first pressure reducing valve and the second mass flow controller connected in sequence; The He/O _x gas route is composed of a He/O _x gas cylinder connected in sequence, a second pressure reducing valve, a third mass flow controller, a second three-way solenoid valve and a third three-way solenoid valve; The He/CH ₄ gas route is composed of He/CH ₄ gas cylinder gas, a third pressure reducing valve, a fourth mass flow controller and a six-way valve connected in sequence; The first pressure reducing valve is connected to the first mass flow controller and the second mass flow controller through a first three-way joint; the first mass flow controller is connected to the second mass flow controller through a second three-way joint The normally open end of the first three-way solenoid valve is connected with the normally closed end of the second three-way solenoid valve; the normally closed end of the first three-way solenoid valve is connected with the three ports of the six-way valve; The normally open end of the one-way electromagnetic valve is connected with the common end of the third three-way electromagnetic valve; the common end of the second three-way electromagnetic valve is connected with the third mass flow controller and the six-way electromagnetic valve through the third three-way joint. The four ports of the through valve are connected; the two ports of the six-way valve are connected with the five ports, as the quantitative loop of the internal standard gas of methane; the six ports of the six-way valve are set as the exhaust end of the He/CH gas _; The fourth mass flow controller is connected to one port of the six-way valve; The sampling-analysis gas path system includes a sampling gas path, an analysis-oxidation furnace and an analysis gas path; The analysis-oxidation furnace includes an analysis-oxidation furnace tube; the analysis-oxidation furnace tube includes an analysis furnace main pipe, an analysis furnace auxiliary tube and an oxidation furnace tube; The sampling gas path includes a cutting head, a volatile organic compound removal tube, a ball valve, a desorption-oxidation furnace tube, a two-way solenoid valve, a fifth mass flow controller and a sampling pump connected in sequence; in the sampling gas path, The VOCs removal pipe is connected with the main air inlet of the ball valve; the front end of the air outlet of the ball valve is provided with an air inlet on one side, and the air outlet of the ball valve is connected with the air inlet on the side of the ball valve; the side air inlet of the ball valve is The air inlet is connected to the common end of the first three-way electromagnetic valve; the gas outlet of the ball valve is connected to the main pipe of the analysis-oxidation furnace through the first joint; the main air inlet of the two-way electromagnetic valve is The rear end is provided with a side air inlet, and the main air inlet of the two-way solenoid valve communicates with the side air inlet of the two-way solenoid valve; the main air inlet of the two-way solenoid valve passes through the second joint It is connected with the secondary pipe of the desorption furnace of the analysis-oxidation furnace tube; the side air inlet of the two-way solenoid valve is connected with the second mass flow controller; the gas outlet of the two-way valve is connected with the fifth The mass flow controller is connected; The analysis gas path includes the analysis-oxidation furnace tube of the analysis-oxidation furnace connected in sequence, the fourth three-way solenoid valve, a non-dispersive infrared spectrum detector and a flow meter; A reflection laser correction system and a transmission laser correction system are arranged inside the first joint and the second joint; the outlet of the oxidation furnace tube is connected to the common end of the fourth three-way solenoid valve through a third joint; the The normally closed end of the fourth three-way electromagnetic valve is connected with the normally closed end of the third three-way electromagnetic valve; the normally open end of the fourth three-way electromagnetic valve is connected with the inlet port of the non-dispersive infrared spectrum detector; The outlet port of the non-dispersive infrared spectrum detector is connected with the inlet port of the flowmeter; the outlet port of the flowmeter is set as the tail gas emptying port. 2. as claimed in claim 1, the aerosol carbonaceous component in situ on-line collection analyzer, is characterized in that, in the said carrier gas path system and the sampling-analysis gas path system, the cylinder gas and pressure relief valve are connected , Mass flow controller, sampling and cutting head, volatile organic compound removal tube and ball valve are made of stainless steel or copper tubes; the rest of the gas circuit is made of stainless steel tubes, copper tubes, silicone rubber tubes or PTFE tubes. 3. as claimed in claim 1, the aerosol carbonaceous component in situ on-line collection analyzer, is characterized in that, the analysis-oxidation furnace tube also includes a first branch pipe, a second branch pipe and a cover in the main pipe of the analysis furnace In the sample tube, the axis of each pipe fitting is on the same plane; the analysis-oxidation furnace also includes a shell, an electric furnace wire and a K-type thermocouple; the K-type thermocouple includes the first temperature-measuring K-type thermocouple and the second thermocouple Two temperature-measuring K-type thermocouples; the analysis-oxidation furnace tube is placed in the shell; the middle part of the oxidation furnace tube is filled with an analytically pure grade manganese dioxide catalyst; The sample injection pipe is fixedly connected with the main pipe of the analysis furnace through the fourth joint; the main pipe of the analysis furnace and the secondary pipe of the analysis furnace are in a straight line, and a quartz porous plate is fired in the middle of the connection, and the sample injection A quartz membrane is placed between the tube and the porous quartz plate; the analysis-oxidation furnace tube is wrapped with an electric furnace wire at the position corresponding to the quartz porous plate; The oxidation furnace pipe and the first branch pipe are perpendicular to the straight line where the analytical furnace main pipe is located, and both are located on both sides of the straight line; the front end of the first branch pipe is sealed, and the first temperature measuring pipe is inserted into it. K-type thermocouple, and fixed by the fifth joint, the top of the first temperature-measuring K-type thermocouple is in contact with the front end of the first branch pipe; the second branch pipe is arranged in the middle part of the oxidation furnace tube close to the analysis One side of the furnace main pipe, and perpendicular to the oxidation furnace tube, the front end of the second branch tube is not sealed; the second temperature-measuring K-type thermocouple is placed outside the oxidation furnace tube, and the second temperature-measuring K-type thermocouple The front end of the couple contacts the outer wall of the oxidation furnace tube, and the oxidation furnace tube and the second temperature measuring K-type thermocouple are wrapped in another electric furnace wire; the gas outlet of the second branch pipe is connected to the second branch pipe through the sixth joint The normally open end of the third three-way solenoid valve mentioned above is connected. 4. as claimed in claim 3, the aerosol carbonaceous component in-situ online collection analyzer is characterized in that, the shell of the described analysis-oxidation furnace is an aluminum plate, and there is a layer of insulation board close to the inner wall of the shell, and a part of the The heat preservation board divides the furnace into two parts: the desorption chamber and the oxidation chamber: the main pipe of the desorption furnace, the auxiliary pipe of the desorption furnace and the first branch pipe are located in the desorption chamber; the oxidation furnace pipe and the second branch pipe are located in the desorption chamber. The oxidation chamber; the heat preservation board is made of mullite material; the heat preservation material of ceramic fiber cotton is filled inside the oxidation chamber. 5. as claimed in claim 4, the aerosol carbonaceous component in-situ on-line acquisition analyzer is characterized in that, the analysis-oxidation furnace is provided with a fan on one side by the side of the main pipe of the analysis furnace, and the fan of the fan is The position of the air outlet corresponds to the position of the quartz porous plate in the analysis chamber; the position of the corresponding air outlet of the shell and the insulation plate is hollowed out; the upper part of the shell is provided with a ventilation pipe, and the connection between the ventilation pipe and the shell Located directly above the porous quartz plate, the joint between the shell and the insulation plate corresponding to the ventilation pipe and the shell is hollowed out; the outlet of the ventilation pipe is set at the original position of the carbonaceous component of the aerosol On-line acquisition outside of the analyzer. 6. as claimed in claim 3, the aerosol carbonaceous component in situ on-line collection analyzer is characterized in that, the operating voltage of the electric furnace wire is 220V, and the power is 1500W, and its outside is covered with a quartz fiber sleeve, and the The electric furnace wire adopts proportional differential integral combined with pulse width modulation method for heating control. 7. as claimed in claim 3, the aerosol carbonaceous component in-situ on-line acquisition analyzer is characterized in that, each part of the analysis-oxidation furnace tube is a high temperature resistant quartz material, and the main pipe of the analysis furnace has an outer diameter of 20 millimeters, the outer diameter of the auxiliary pipe of the desorption furnace is 10 millimeters, the outer diameter of the middle part of the oxidation furnace tube is 13 millimeters, the outer diameter of the first branch pipe and the second branch pipe is 6.35 millimeters, and the sample injection pipe The outer diameter is 16 mm. 8. as claimed in claim 3, the aerosol carbonaceous component in situ on-line collection analyzer, is characterized in that, the quartz porous plate is a circular quartz plate evenly distributed with six small circular holes, the circular ring The inner diameter of the quartz plate is 6 mm, the outer diameter is 17 mm, and the diameter of the small circular hole is 2 mm; the quartz membrane is in contact with the quartz porous plate, and the quartz porous plate plays a supporting role for the quartz membrane . 9. aerosol carbonaceous component in-situ online acquisition analyzer as claimed in claim 1, is characterized in that, described reflective laser correction system comprises a laser transmitter, quartz plate, the first optical filter and a reflected laser signal detector; the transmission laser correction system includes the laser emitter, the quartz plate, a second optical filter and a transmission laser signal detector; the reflection laser correction system is located inside the first joint: the second A laser emitter groove for inserting and fixing the laser emitter is arranged on the outside of a joint, and the centerline of the laser emitter groove coincides with the centerline of the first joint; the quartz plate passes through the O-ring Sealed and fixed in the groove of the laser emitter, and placed close to the front end of the laser emitter; the front end of the groove of the laser emitter is also provided with a first air groove communicated with the sampling tube; A second air groove perpendicular to the first air groove is arranged on the side of a joint, and the first air groove and the second air groove communicate with each other; Set and fix the reflected laser signal detector groove of the reflected laser signal detector; the first optical filter is sealed and fixed in the reflected laser signal detector groove by an O ring, and is close to the reflected laser signal The front end of the detector is placed; the transmission laser calibration system is located inside the second joint: a transmission laser signal detector groove for inserting and fixing the transmission laser signal detector is arranged on the outside of the second joint, and its center The line coincides with the center line of the second joint; the second optical filter is sealed and fixed in the groove of the transmitted laser signal detector through an O-ring, and placed close to the front end of the transmitted laser signal detector; The front end of the transmission laser signal detector groove is also provided with a third air groove communicating with the secondary pipe; the side of the second joint is also provided with a fourth air groove perpendicular to the third air groove, the The third air groove communicates with the fourth air groove. 10. as claimed in claim 9, the aerosol carbonaceous component in situ on-line collection analyzer, is characterized in that, said laser emitter adopts the point-shaped red light whose central emission wavelength is 660nm, power is 50mW and emission frequency is 1Hz Laser emitter; the filter adopts a filter with a center wavelength of 660nm and a bandwidth of 8nm; the transmitted laser signal detector and the reflected laser signal detector are photodiodes capable of producing highly sensitive linear responses to 660nm laser light . 11. Utilize the online collection and analysis method of the in-situ online collection and analysis instrument of aerosol carbonaceous components described in any one of claims 1 to 10, which successively comprises a sampling stage, a purging stage, an OC analysis stage, an EC analysis stage, and a methane quantitative stage , methane calibration stage, instrument cooling and standby stage; specifically include the following processes: 1) Sampling process: collect air samples through the sampling gas path; 2) Purging process: He main gas, He purge gas and He/O _x carrier gas are mixed together for purging; 3) OC analysis process: OC is gradually volatilized by thermal analysis in an oxygen-free environment of He gas, converted into CO ₂ and quantified by a non-dispersive infrared spectroscopy detector; 4) EC analysis process: EC is oxidized in an oxidizing environment, further converted into CO ₂ and quantified by a non-dispersive infrared spectroscopy detector; 5) Methane quantitative process: Inject He/CH ₄ internal standard gas into the pipeline between ports 2 and 5 of the six-way valve; after the He/CH ₄ internal standard gas is full, the excess He/CH ₄ internal standard gas passes through 6 ports of the 6-way valve are discharged; 6) Methane calibration process: He main gas and He/O _x carrier gas mixture blow out and oxidize the original He/CH ₄ internal standard gas in the pipeline between port 2 and port 5 of the six-way valve, and convert it into CO ₂ Non-dispersive infrared spectroscopy detector quantification; 7) Cooling process: the instrument cools down, automatically stops the analysis stage, saves the data and curves, and enters the standby process; 8) Standby process: waiting for the next sampling analysis.