CN114646509A - Dilution sampling system for pollutants discharged by civil combustion source - Google Patents
Dilution sampling system for pollutants discharged by civil combustion source Download PDFInfo
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- CN114646509A CN114646509A CN202210252763.XA CN202210252763A CN114646509A CN 114646509 A CN114646509 A CN 114646509A CN 202210252763 A CN202210252763 A CN 202210252763A CN 114646509 A CN114646509 A CN 114646509A
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- 239000003344 environmental pollutant Substances 0.000 title claims abstract description 33
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/02—Devices for withdrawing samples
- G01N1/22—Devices for withdrawing samples in the gaseous state
- G01N1/2202—Devices for withdrawing samples in the gaseous state involving separation of sample components during sampling
- G01N1/2205—Devices for withdrawing samples in the gaseous state involving separation of sample components during sampling with filters
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/02—Devices for withdrawing samples
- G01N1/22—Devices for withdrawing samples in the gaseous state
- G01N1/2202—Devices for withdrawing samples in the gaseous state involving separation of sample components during sampling
- G01N1/2211—Devices for withdrawing samples in the gaseous state involving separation of sample components during sampling with cyclones
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/02—Devices for withdrawing samples
- G01N1/22—Devices for withdrawing samples in the gaseous state
- G01N1/2247—Sampling from a flowing stream of gas
- G01N1/2258—Sampling from a flowing stream of gas in a stack or chimney
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/38—Diluting, dispersing or mixing samples
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/02—Devices for withdrawing samples
- G01N1/22—Devices for withdrawing samples in the gaseous state
- G01N1/2247—Sampling from a flowing stream of gas
- G01N1/2258—Sampling from a flowing stream of gas in a stack or chimney
- G01N2001/2261—Sampling from a flowing stream of gas in a stack or chimney preventing condensation (heating lines)
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/02—Devices for withdrawing samples
- G01N1/22—Devices for withdrawing samples in the gaseous state
- G01N1/2247—Sampling from a flowing stream of gas
- G01N2001/2264—Sampling from a flowing stream of gas with dilution
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/38—Diluting, dispersing or mixing samples
- G01N2001/386—Other diluting or mixing processes
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Abstract
The invention provides a dilution sampling system for pollutants discharged by a civil combustion source, which comprises a primary diluter, a cyclone flow dividing unit, a secondary diluter, a filter membrane collecting unit, a bypass gas unit, an online measuring unit I and an online measuring unit II, wherein the primary diluter is positioned at the front end of the system and close to a combustion source discharge port, the temperature of the primary diluter is controlled to be the same as the temperature of flue gas, the flue gas and the diluent gas are stably converged in the primary diluter, and after uniform mixing is realized through a contraction mixing hole, the flue gas enters the cyclone flow dividing unit through a heat-preservation smoke gun, the cyclone flow dividing unit cuts large particles and equally divides aerosol, and the filter membrane collecting unit controls the flow by adopting a compensation type flow limiting hole method; the online measurement unit I realizes online measurement of high-concentration pollutants; the concentration of the particulate matters is further reduced by the secondary diluter, and then the online measurement is carried out by the online measurement unit II; the bypass air unit controls the flow in a flow limiting hole mode so as to balance the flow used by other instruments.
Description
Technical Field
The invention belongs to the technical field of environmental monitoring, and particularly relates to a dilution sampling system for pollutants discharged by a civil combustion source.
Background
Pollutants generated by combustion and emission of civil sources greatly contribute to atmospheric environmental pollution; compared with other source emissions, the civil source combustion has the following characteristics: the method has the advantages that firstly, the method belongs to unorganized emission, the dispersibility is strong, such as heating and cooking by using coal of residents, secondly, better post-treatment emission reduction measures are not usually provided, and thirdly, the emission characteristics of different types of combustion sources are different, including different fuels, different stoves and different combustion modes. Therefore, scientific and reasonable sampling measurement is necessary for pollutants discharged by combustion of civil sources.
At present, there are many researches on the emission of a fixed pollution source, for example, a patent No. 201410340512.2 relates to a PM2.5 dilution sampling device emitted by a fixed pollution source, which can simulate the situation that flue gas is mixed with the atmosphere after coming out from a discharge port, and a filter membrane is used for collecting a PM2.5 sample, but the system has the following problems in the process of being applied to a civil source: the volume is larger, the aerosol flow and the diluent gas flow are required to be larger, and the function of offline collecting PM2.5 is achieved. The patent of patent application No. 202110095623.1 relates to a furnace flue gas pollutant field detection system, which can realize 24-hour measurement of the pollutant discharged by civil furnaces burning solid fuel, but has the following problems: the system only has a primary diluter, temperature control and heat preservation are not performed, and flue gas can be quickly condensed in the process of being discharged into the atmosphere to block a sampling pipeline; secondly, the diluter adopts a T-shaped joint mode, so that the loss of smoke particles at the joint is large; thirdly, the flow control adopts a rotor flow meter mode, the flow fluctuation is large, and the small flow fluctuation under the condition of low flow has great influence on the dilution ratio; fourthly, the total flow is small, other on-line measuring instruments cannot be connected behind the diluter, and the expandability of the system is poor; fifthly, the flow rate of the airflow of the filter membrane is too small, and the filter membrane can collect the required particle amount only in a long time; especially for civil combustion source emission, in the processes of ignition from a stove, primary combustion, complete combustion and gradual extinction, the types and characteristics of pollutants emitted in each stage are different, and the pollutants emitted in different stages need to be distinguished and measured.
In conclusion, a dilution sampling system which aims at pollutants discharged by civil source combustion and is more scientific and reasonable is designed, so that the portable measurement requirement is met, the particle loss is less, the flow control is more accurate, the expandability of the system is stronger, and the problem to be solved urgently is solved.
Disclosure of Invention
Aiming at overcoming a series of defects in the prior art, the invention provides a dilution sampling system for pollutants discharged by a civil combustion source, which comprises a primary diluter 1, a cyclone diversion unit 2, a secondary diluter 3, a filter membrane collecting unit 4, a bypass gas unit 5, an online measuring unit I6 and an online measuring unit II7, and is characterized in that the primary diluter 1 is positioned at the front end of the system close to a combustion source discharge port, the system automatically adjusts the temperature of the primary diluter 1 to be the same as the temperature of flue gas so as to prevent the flue gas from condensing, the flue gas and the diluent gas are stably converged in the primary diluter 1, are uniformly mixed through a contraction mixing hole and then enter the cyclone diversion unit 2 through a heat-insulating smoke gun, the cyclone diversion unit 2 cuts large particles and equally diverts aerosol, and the diverted fluids respectively enter the filter membrane collecting unit 4, An on-line measuring unit I6, a secondary diluter 3 and a bypass gas unit 5, wherein,
the primary diluter 1 adopts a mode of thermal dilution and normal-pressure mixing;
the secondary diluter 3 is used for normal temperature dilution and adopts a dilution gas closed loop mode;
the filter membrane acquisition unit 4 works in a simultaneous sampling mode or a sequential sampling mode, and the flow is controlled by adopting a compensation type restricted orifice method;
the online measurement unit I6 realizes online measurement of high-concentration pollutants;
the online measurement unit II7 realizes online measurement of low-concentration particulate pollutants;
the bypass air unit 5 controls the flow in a flow limiting hole mode to balance the flow used by other instruments.
Preferably, the primary diluter 1 comprises a diluter I1-1, a smoke temperature sensor 1-2, a smoke flow measuring module 1-3, a temperature control module 1-4, a heat preservation smoke gun 1-5, a silica gel drying pipe 1-6, a high-efficiency filter I1-7, a temperature and humidity pressure module I1-8, a mass flow meter I1-9, a compression pump 1-10 and a high-efficiency filter II 1-11, wherein,
the diluter I1-1 is of a normal-pressure mixing structure, is positioned at the top end of the heat-preservation smoke gun 1-5 and is close to a civil combustion source exhaust outlet;
the smoke temperature sensor 1-2 is used for measuring the smoke temperature;
the flue gas volume flow measuring module 1-3 measures the volume flow of the flue gas;
the temperature control module 1-4 comprises a resistance heater and a thermistor temperature sensor, and the temperature control module 1-4 dynamically adjusts the temperature of the diluter I1-1 according to the temperature measured by the smoke temperature sensor 1-2 so that the temperature of the diluter I1-1 is the same as that of the smoke temperature sensor;
the heat preservation smoke gun 1-5 is used for connecting the diluter I1-1 and the cyclone flow dividing unit 2;
air entering from the silica gel drying tube 1-6 sequentially passes through the high-efficiency filter I1-7, the temperature and humidity pressure module I1-8, the mass flow meter I1-9, the compression pump 1-10 and the high-efficiency filter II 1-11 to obtain clean, dry and stable-flow dilution air, wherein the silica gel drying tube 1-6 is used for drying the air, the high-efficiency filter I1-7 is used for removing particulate matters in the air, and the temperature and humidity pressure module I1-8 is used for measuring temperature, relative humidity and absolute pressure information of the dilution air; the mass flow meter I1-9 is used for measuring the mass flow of the diluent gas, the outlet of the mass flow meter I1-9 is connected with the inlet of the compression pump 1-10, and the outlet of the compression pump 1-10 is connected with the high-efficiency filter II 1-11;
flue gas enters the diluter I1-1 from an inlet of the flue gas flow measuring module 1-3, diluent gas enters from the side of the diluter I1-1, and the flue gas and the diluent gas which are both at the normal pressure level are converged at a closing opening of the diluter I1-1.
Preferably, the diluter I1-1 is made of stainless steel, the temperature control module 1-4 is fixedly arranged on the surface of the diluter I1-1, and the rest parts are wrapped by heat insulation cotton;
the smoke temperature sensor 1-2 adopts a platinum resistor temperature sensor, and the temperature measuring range is-40- +200 ℃;
the flue gas flow measurement module 1-3 is a stainless steel capillary tube, the inner diameter of the tube is 1.8mm, the length of the tube is 80mm, the measured flow range is 0.2-2.0L/min at normal temperature, the chamfer angle of the outlet end is designed to realize stable convergence of diluent gas and flue gas, and the flow measurement adopts a mode of measuring the pressure difference at two ends of the capillary tube;
the temperature control range of the temperature control modules 1-4 is 0-100 ℃;
the heat-preservation smoke gun 1-5 adopts a double-layer stainless steel sleeve mode, heat-preservation cotton is wrapped in the middle of the heat-preservation smoke gun, the central stainless steel pipe is connected with the diluter I1-1 in a clamping sleeve joint mode, stable transition from the smoke temperature to the atmospheric environment temperature is realized, the generation of condensed water is prevented, and the loss of particles in a pipeline is reduced;
the compressor pump 1-10 adjusts the air flow by means of duty ratio adjustment, the adjusted flow range is 5-15L/min, the main board is controlled to continuously acquire mass flow information and temperature pressure information to calculate the volume flow of the dilution air at the ambient temperature, and the dilution ratio range is 5:1-30: 1.
Preferably, the cyclone flow dividing unit 2 comprises a cyclone cutter and an aerosol flow divider, wherein the inlet of the cyclone cutter is connected to the outlet of the heat-preservation smoke gun 1-5 by adopting a conductive silica gel hose, and the outlet of the cyclone cutter is connected to the inlet 2-1 of the flow divider by adopting a clamping sleeve; the aerosol splitter is provided with six splitter outlets 2-2 which are circumferentially and symmetrically distributed, and the smoke enters from the splitter inlet 2-1 and reaches the six splitter outlets 2-2 after the smoke is smoothly turned for 90 degrees inside the smoke.
Preferably, the cutting particle size of the cyclone cutter is 2.5 microns, and the corresponding flow rate is 10L/min; splitter inlet 2-1 has an outside diameter of 10mm and is compatible with the cyclone cutters and splitter outlet 2-2 has an outside diameter comprised of 3/8 inches and 1/4 inches for each modular unit downstream.
Preferably, the secondary diluter 3 is provided with two air inlets and two air outlets, namely a secondary diluter sample gas inlet 3-1, a secondary diluter dilution gas inlet 3-2, a secondary diluter excess gas outlet 3-3 and a secondary diluter sample gas outlet 3-4, wherein the secondary diluter sample gas inlet 3-1 is connected with one of the splitter outlets 2-2; the second-stage diluter dilution gas inlet 3-2, the second-stage diluter excess gas outlet 3-3 and the adjustable fan 3-8 form a closed-loop gas path: the gas flowing out of the excess gas outlet 3-3 of the secondary diluter passes through a high-efficiency filter III 3-5, a temperature, humidity and pressure module II 3-6, a mass flow meter II 3-7, an adjustable fan 3-8 and a high-efficiency filter IV 3-9 and finally flows into a dilution gas inlet 3-2 of the secondary diluter; the flow of the dilution gas inlet 3-2 of the secondary diluter is equal to the flow of the redundant gas outlet 3-3 of the secondary diluter so as to ensure that the flow of the sample gas outlet 3-4 of the secondary diluter is equal to the flow of the sample gas inlet 3-1 of the secondary diluter, the dilution ratio of the secondary diluter 3 is adjusted by adjusting the ratio of the two flows, and the adjustment range of the dilution ratio is 3:1-30: 1.
Preferably, the filter membrane collecting unit 4 comprises three filter membrane collecting channels and a vacuum pump 4-5 which are connected in parallel, each filter membrane collecting channel comprises a filter membrane holder 4-1, a proportional valve 4-2, a high-efficiency filter V4-3 and a flow limiting hole I4-4 which are sequentially connected together, wherein the filter membrane holder 4-1 is used for placing a 47mm filter membrane, an inlet of each filter membrane holder 4-1 is respectively connected with a splitter outlet 2-2 through a conductive silica gel hose, an outlet of the filter membrane holder 4-1 is connected with an inlet of the proportional valve 4-2, an outlet of the proportional valve 4-2 is connected with the high-efficiency filter V4-3 to strengthen protection on the flow limiting hole I4-4, and gas paths of the three flow limiting holes I4-4 are connected to the vacuum pump 4-5 after being converged, the flow rate of the first filter membrane collecting channel is set to be 2.5L/min.
Preferably, the filter membrane collecting unit 4 comprises two modes of simultaneous sampling and sequential sampling, wherein the simultaneous sampling mode is to synchronously open or close three filter membrane collecting channels; the sequential sampling mode is that different filter membrane collecting channels are opened for sampling according to different stages of combustion, and the division of the different stages of combustion can be divided according to the results of the on-line measuring instrument I6 or the on-line measuring instrument II7, or divided according to the time interval of the combustion.
Preferably, the flow regulation mode of the filter membrane collection unit 4 is a compensation type flow limiting hole mode, when the filter membrane collects particulate matters, the pressure drop generated by the airflow passing through the filter membrane is gradually increased along with the enrichment of the particulate matters on the filter membrane, the proportional valve 4-2 is regulated to keep the numerical value of the pressure drop constant by monitoring the pressure drop before the flow divider outlet 2-2 and each flow limiting hole I4-4, the proportional valve 4-2 is tightly regulated in the regulation direction under the initial state, and the pressure drop of the filter membrane is compensated by loosening the proportional valve 4-2 along with the gradual increase of the pressure drop of the filter membrane.
Preferably, the bypass gas unit 5 comprises a high-efficiency filter VI 5-1 and a flow limiting hole II 5-2, and when an instrument used by the system is newly added or reduced or the flow used by a part of instruments or units in the system is changed, the flow of the system is balanced in a mode of replacing the flow limiting hole II 5-2; the flow limiting hole I4-4 and the flow limiting hole II 5-2 are connected to the same vacuum pump 4-5, and an absolute pressure measuring port is arranged in front of the vacuum pump 4-5 to ensure that the flow limiting holes are in a limiting flow limiting state.
Preferably, the on-line measuring unit I6 is arranged behind the primary diluter 1 and is provided with a gas monitor and PM2.5Mass concentration monitor, black carbon monitor and/or other instruments suitable for high concentration measurement, PM2.5The mass concentration monitor corrects the light heat dissipation signal by using the weighing result of the filter membrane;
and the online measurement unit II7 is positioned behind the secondary diluter 3 and is provided with a scanning particle size spectrometer, a particle mass spectrum and/or other online measurement instruments for low-concentration particle measurement occasions.
The measuring instrument in the online measuring unit I6 and the measuring instrument in the online measuring unit II7 can be directly interchanged without affecting the flow balance of the system.
Compared with the prior art, the invention has the following beneficial effects:
1) in the invention, the primary diluter is positioned at the front end of the system close to the source discharge port, the temperature of the primary diluter is controlled to be the same as the temperature of the flue gas, the flue gas and the dilution gas are stably converged and uniformly mixed through the contraction mixing hole, the temperature of the flue gas is gradually reduced to the ambient atmospheric temperature through the heat-preservation smoke gun, the condensation of the flue gas is avoided, and meanwhile, the loss of particulate matters in a pipeline can be greatly reduced due to the increase of the aerosol flow in the heat-preservation smoke gun;
2) in the invention, the filter membrane acquisition unit and the bypass gas unit adopt a flow limiting hole mode to control the flow, the volume is small, the control is accurate, and the filter membrane acquisition unit adopts a compensation type flow limiting hole method, so that the problem of flow reduction caused by filter membrane pressure drop can be effectively solved;
3) in the invention, the filter membrane acquisition unit comprises three filter membranes and supports two modes of simultaneous sampling and sequential sampling;
4) in the invention, an interface of the online measuring instrument I is reserved behind the first-stage diluter, and meanwhile, the second-stage diluter is added to further reduce the concentration of the particulate matters and then measure the particulate matters by using an instrument suitable for a low-concentration measuring environment, so that the interfaces are rich and the system expansibility is strong;
5) the system has high integration level, small volume and simple and convenient operation, and can be used for off-line acquisition and on-line measurement of pollutants discharged by a civil combustion source.
Drawings
FIG. 1 is a schematic view of the present invention;
FIG. 2 is a schematic diagram of a primary diluter according to the invention;
FIG. 3 is a schematic view of an aerosol diverter of the present invention;
FIG. 4 is a schematic diagram of a two-stage diluter according to the invention;
FIG. 5 is a schematic diagram of a filter membrane collection unit and a bypass gas unit according to the present invention;
the reference numbers in the figures are:
1: primary diluter, 2: cyclone flow-dividing unit, 3: second-stage diluter, 4: filter membrane collection unit, 5: bypass gas unit, 6: on-line measurement unit i, 7: an online measurement unit II;
1-1: the device comprises a diluter I, 1-2 parts of a smoke temperature sensor, 1-3 parts of a smoke flow measuring module, 1-4 parts of a temperature control module, 1-5 parts of a heat preservation smoke gun, 1-6 parts of a silica gel drying pipe, 1-7 parts of a high-efficiency filter I, 1-8 parts of a temperature and humidity pressure module I, 1-9 parts of a mass flowmeter I, 1-10 parts of a compression pump and 1-11 parts of a high-efficiency filter II;
2-1, inlet of the flow divider, and 2-2, outlet of the flow divider;
3-1, sample gas inlet of the secondary diluter, 3-2, diluent gas inlet of the secondary diluter, 3-3, redundant gas outlet of the secondary diluter and 3-4, sample gas outlet of the secondary diluter; 3-5 parts of a high-efficiency filter III, and 3-6 parts of a temperature and humidity pressure module II; 3-7 parts of a mass flow meter II, 3-8 parts of an adjustable fan, and 3-9 parts of a high-efficiency filter IV;
4-1 parts of a filter membrane support, 4-2 parts of a proportional valve, 4-3 parts of a high-efficiency filter V, 4-4 parts of a restricted orifice I and 4-5 parts of a vacuum pump;
5-1 parts of a high-efficiency filter VI and 5-2 parts of a restricted orifice II.
Detailed Description
In order to make the implementation objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be described in more detail below with reference to the accompanying drawings in the embodiments of the present invention. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, but not all embodiments of the invention.
All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The embodiments and the directional terms described below with reference to the drawings are exemplary and intended to be used in the explanation of the invention, and should not be construed as limiting the invention.
In a wide embodiment of the invention, the dilution sampling system for pollutants discharged by a civil combustion source comprises a primary diluter 1, a cyclone flow dividing unit 2, a secondary diluter 3, a filter membrane collecting unit 4, a bypass gas unit 5, an online measuring unit I6 and an online measuring unit II7, and is characterized in that the primary diluter 1 is positioned at the front end of the system and close to a combustion source discharge port, the system automatically adjusts the temperature of the primary diluter 1 to be the same as the temperature of flue gas so as to prevent the flue gas from condensing, the flue gas and the diluent gas are stably converged in the primary diluter 1, and after uniform mixing is realized through a contraction mixing hole, the flue gas and the diluent gas enter the cyclone flow dividing unit 2 through a heat preservation smoke gun, the cyclone flow dividing unit 2 cuts large particles and equally divides aerosol, and divided fluids respectively enter the filter membrane collecting unit 4, the online measuring unit I6, the secondary diluter 3 and the bypass gas unit 5, wherein the content of the first and second substances,
the primary diluter 1 adopts a mode of thermal dilution and normal-pressure mixing;
the secondary diluter 3 is used for normal temperature dilution and adopts a dilution gas closed loop mode;
the filter membrane acquisition unit 4 works in a simultaneous sampling mode or a sequential sampling mode, and the flow is controlled by adopting a compensation type restricted orifice method;
the online measurement unit I6 realizes online measurement of high-concentration pollutants;
the online measurement unit II7 realizes online measurement of low-concentration particulate pollutants;
the bypass air unit 5 controls the flow in a flow limiting hole mode to balance the flow used by other instruments.
Preferably, the primary diluter 1 comprises a diluter I1-1, a smoke temperature sensor 1-2, a smoke flow measuring module 1-3, a temperature control module 1-4, a heat preservation smoke gun 1-5, a silica gel drying pipe 1-6, a high-efficiency filter I1-7, a temperature and humidity pressure module I1-8, a mass flow meter I1-9, a compression pump 1-10 and a high-efficiency filter II 1-11, wherein,
the diluter I1-1 is of a normal-pressure mixing structure, is positioned at the top end of the heat-preservation smoke gun 1-5 and is close to a civil combustion source exhaust outlet;
the smoke temperature sensor 1-2 is used for measuring the smoke temperature;
the flue gas volume flow measuring module 1-3 measures the volume flow of the flue gas;
the temperature control module 1-4 comprises a resistance heater and a thermistor temperature sensor, and the temperature control module 1-4 dynamically adjusts the temperature of the diluter I1-1 according to the temperature measured by the smoke temperature sensor 1-2 so that the temperature of the diluter I1-1 is the same as that of the smoke temperature sensor;
the heat preservation smoke gun 1-5 is used for connecting the diluter I1-1 and the cyclone flow dividing unit 2;
air entering from the silica gel drying tube 1-6 sequentially passes through the high-efficiency filter I1-7, the temperature and humidity pressure module I1-8, the mass flow meter I1-9, the compression pump 1-10 and the high-efficiency filter II 1-11 to obtain clean, dry and stable-flow dilution air, wherein the silica gel drying tube 1-6 is used for drying the air, the high-efficiency filter I1-7 is used for removing particulate matters in the air, and the temperature and humidity pressure module I1-8 is used for measuring temperature, relative humidity and absolute pressure information of the dilution air; the mass flow meter I1-9 is used for measuring the mass flow of the diluent gas, the outlet of the mass flow meter I1-9 is connected with the inlet of the compression pump 1-10, and the outlet of the compression pump 1-10 is connected with the high-efficiency filter II 1-11;
flue gas enters the diluter I1-1 from an inlet of the flue gas flow measuring module 1-3, diluent gas enters from the side of the diluter I1-1, and the flue gas and the diluent gas which are both at the normal pressure level are converged at a closing opening of the diluter I1-1.
Preferably, the diluter I1-1 is made of stainless steel, the temperature control module 1-4 is fixedly arranged on the surface of the diluter I1-1, and the rest parts are wrapped by heat insulation cotton;
the smoke temperature sensor 1-2 adopts a platinum resistor temperature sensor, and the temperature measuring range is-40- +200 ℃;
the flue gas flow measuring module 1-3 is a stainless steel capillary tube, the inner diameter of the tube is 1.8mm, the length of the tube is 80mm, the measured flow range is 0.2-2.0L/min at normal temperature, the chamfer of the outlet end is designed to realize the stable confluence of the diluent gas and the flue gas, and the flow measurement adopts a mode of measuring the pressure difference at two ends of the capillary tube;
the temperature control range of the temperature control modules 1-4 is 0-100 ℃;
the heat-preservation smoke gun 1-5 adopts a double-layer stainless steel sleeve mode, heat-preservation cotton is wrapped in the middle of the heat-preservation smoke gun, the central stainless steel pipe is connected with the diluter I1-1 in a clamping sleeve joint mode, stable transition from the smoke temperature to the atmospheric environment temperature is realized, the generation of condensed water is prevented, and the loss of particles is reduced;
the compressor pump 1-10 adjusts the air flow by means of duty ratio adjustment, the adjusted flow range is 5-15L/min, the main board is controlled to continuously acquire mass flow information and temperature pressure information to calculate the volume flow of the dilution air at the ambient temperature, and the dilution ratio range is 5:1-30: 1.
Preferably, the cyclone flow dividing unit 2 comprises a cyclone cutter and an aerosol flow divider, wherein the inlet of the cyclone cutter is connected to the outlet of the heat-preservation smoke gun 1-5 by adopting a conductive silica gel hose, and the outlet of the cyclone cutter is connected to the inlet 2-1 of the flow divider by adopting a clamping sleeve; the aerosol splitter is provided with six splitter outlets 2-2 which are circumferentially and symmetrically distributed, and the smoke enters from the splitter inlet 2-1 and reaches the six splitter outlets 2-2 after the smoke is smoothly turned for 90 degrees inside the smoke.
Preferably, the cutting particle size of the cyclone cutter is 2.5 microns, and the corresponding flow rate is 10L/min; splitter inlet 2-1 has an outside diameter of 10mm and is matched to the cyclone cutters and splitter outlet 2-2 has an outside diameter of 3/8 inches and 1/4 inches for each modular unit downstream.
Preferably, the secondary diluter 3 is provided with two air inlets and two air outlets, namely a secondary diluter sample gas inlet 3-1, a secondary diluter dilution gas inlet 3-2, a secondary diluter excess gas outlet 3-3 and a secondary diluter sample gas outlet 3-4, wherein the secondary diluter sample gas inlet 3-1 is connected with one of the splitter outlets 2-2; the second-stage diluter dilution gas inlet 3-2, the second-stage diluter excess gas outlet 3-3 and the adjustable fan 3-8 form a closed-loop gas path: the gas flowing out of the excess gas outlet 3-3 of the secondary diluter passes through a high-efficiency filter III 3-5, a temperature, humidity and pressure module II 3-6, a mass flow meter II 3-7, an adjustable fan 3-8 and a high-efficiency filter IV 3-9 and finally flows into a dilution gas inlet 3-2 of the secondary diluter; the flow of the dilution gas inlet 3-2 of the secondary diluter is equal to that of the redundant gas outlet 3-3 of the secondary diluter so as to ensure that the flow of the sample gas outlet 3-4 of the secondary diluter is equal to that of the sample gas inlet 3-1 of the secondary diluter, the dilution ratio of the secondary diluter 3 is adjusted by adjusting the ratio of the two flows, and the adjustment range of the dilution ratio is 3:1-30: 1.
Preferably, the filter membrane collecting unit 4 comprises three filter membrane collecting channels and a vacuum pump 4-5 which are connected in parallel, each filter membrane collecting channel comprises a filter membrane holder 4-1, a proportional valve 4-2, a high-efficiency filter V4-3 and a flow limiting hole I4-4 which are sequentially connected together, wherein the filter membrane holder 4-1 is used for placing a 47mm filter membrane, an inlet of each filter membrane holder 4-1 is respectively connected with a splitter outlet 2-2 through a conductive silica gel hose, an outlet of the filter membrane holder 4-1 is connected with an inlet of the proportional valve 4-2, an outlet of the proportional valve 4-2 is connected with the high-efficiency filter V4-3 to strengthen protection on the flow limiting hole I4-4, and gas paths of the three flow limiting holes I4-4 are connected to the vacuum pump 4-5 after being converged, the flow rate of the first filter membrane collecting channel is set to be 2.5L/min.
Preferably, the filter membrane collecting unit 4 comprises two modes of simultaneous sampling and sequential sampling, wherein the simultaneous sampling mode is to synchronously open or close three filter membrane collecting channels; the sequential sampling mode is that different filter membrane collecting channels are opened for sampling according to different stages of combustion, and the division of the different stages of combustion can be divided according to the results of the on-line measuring instrument I6 or the on-line measuring instrument II7, or divided according to the time interval of the combustion.
Preferably, the flow regulation mode of the filter membrane collection unit 4 is a compensation type flow limiting hole mode, when the filter membrane collects particles, the pressure drop generated by airflow passing through the filter membrane is gradually increased along with the enrichment of the particles on the filter membrane, the pressure difference between the flow splitter outlet 2-2 and the flow limiting hole I4-4 in each path is monitored, the proportional valve 4-2 is regulated to keep the numerical value of the pressure difference constant, the proportional valve 4-2 is tightly regulated in the regulation direction under the initial state, and the pressure drop of the filter membrane is compensated by loosening the proportional valve 4-2 along with the gradual increase of the pressure drop of the filter membrane.
Preferably, the bypass gas unit 5 comprises a high-efficiency filter VI 5-1 and a flow limiting hole II 5-2, and when an instrument used by the system is newly added or reduced or the flow used by a part of instruments or units in the system is changed, the flow of the system is balanced in a mode of replacing the flow limiting hole II 5-2; the flow limiting hole I4-4 and the flow limiting hole II 5-2 are connected to the same vacuum pump 4-5, and an absolute pressure measuring port is arranged in front of the vacuum pump 4-5 to ensure that the flow limiting holes are in a limiting flow limiting state.
Preferably, the on-line measuring unit I6 is positioned behind the primary diluter 1 and is provided with a gas monitor and a PM2.5Mass concentration monitor, black carbon monitor and/or other instruments suitable for high concentration measurement, PM2.5The mass concentration monitor corrects the light heat dissipation signal by using the weighing result of the filter membrane;
and the online measurement unit II7 is positioned behind the secondary diluter 3 and is provided with a scanning particle size spectrometer, a particle mass spectrum and/or other online measurement instruments for low-concentration particle measurement occasions.
The measuring instrument in the online measuring unit I6 and the measuring instrument in the online measuring unit II7 can be directly interchanged without influencing the flow balance of the system.
The present invention will be described in further detail below with reference to the accompanying drawings, which illustrate preferred embodiments of the present invention.
Fig. 1 is a schematic diagram of a dilution sampling system for pollutants discharged by a civil combustion source, and the dilution sampling system mainly comprises a primary diluter 1, a cyclone flow dividing unit 2, a secondary diluter 3, a filter membrane collecting unit 4, a bypass gas unit 5, an online measuring unit I6 and an online measuring unit II 7.
The primary diluter 1 comprises a diluter I1-1, a smoke temperature sensor 1-2, a smoke flow measuring module 1-3, a temperature control module 1-4, a heat preservation smoke gun 1-5, a silica gel drying pipe 1-6, a high-efficiency filter I1-7, a temperature and humidity pressure module I1-8, a mass flow meter I1-9, a compression pump 1-10 and a high-efficiency filter II 1-11. The diluter I1-1 is positioned at the top end of a heat-preservation smoke gun 1-5, is close to a civil combustion source discharge outlet, is of a normal-pressure mixing structure, a smoke temperature sensor 1-2 adopts a platinum resistance temperature sensor, the temperature measurement range is-40 to +200 ℃, the smoke temperature sensor is used for measuring the smoke temperature, the diluter I1-1 adopts stainless steel materials, the surface of the diluter I is fixedly provided with a temperature control module 1-4 by screws, and the rest parts of the diluter I are wrapped by heat-preservation cotton; the temperature control module 1-4 comprises a resistance heater and a thermistor temperature sensor, the temperature of the diluter I is adjusted in time according to the temperature measured by the smoke temperature sensor 1-2, smoke condensation is prevented, and the temperature controllable range of the temperature control module 1-4 is 0-100 ℃.
The dilution gas of the primary diluter 1 is provided by an adjustable compression pump 1-10, the air is dried by a silica gel drying tube 1-6, then particles in the air are removed by a high-efficiency filter I1-7, then the air flow sequentially passes through a temperature, humidity and pressure module I1-8 to measure the temperature, relative humidity and absolute pressure information of the dilution gas, then a mass flow meter I1-9 is used for measuring mass flow, the outlet of the mass flow meter is connected with the inlet of the compression pump 1-10, and the outlet of the compression pump 1-10 is connected with a high-efficiency filter II 1-11, so that the clean, dry and stable dilution gas with stable flow is obtained. Flue gas enters the diluter I1-1 from the inlet of the flue gas flow measuring module 1-3, diluent gas enters from the side of the diluter I1-1, the flue gas and the diluent gas are both at normal pressure level, and the flue gas and the diluent gas are converged at the closing-in opening of the diluter I1-1 and are uniformly mixed through the contraction mixing hole. The flue gas flow measurement module 1-3 is a stainless steel capillary tube, the inner diameter of the tube is 1.8mm, the length of the tube is 80mm, the measurable flow range is 0.2-2.0L/min at normal temperature, the outlet end of the capillary tube is chamfered, stable confluence of dilution gas and flue gas is realized, the flow measurement adopts a mode of measuring the pressure difference at two ends of the capillary tube, and the flue gas volume flow at the flue gas temperature can be calculated according to the ambient atmospheric pressure and the flue gas temperature. The heat preservation smoke gun 1-5 adopts a double-layer stainless steel sleeve mode, heat preservation cotton is wrapped in the middle of the heat preservation smoke gun, the central stainless steel pipe is connected with the diluter I1-1 through a clamping sleeve joint mode, stable transition from smoke temperature to atmospheric environment temperature is achieved, condensate water is prevented from being generated, and loss of particles in a pipeline is reduced.
The outlet of the heat preservation smoke gun 1-5 is connected with the inlet of a PM2.5 cyclone cutter through a conductive silicone tube, the outlet of the cyclone cutter is directly connected with the inlet 2-1 of an aerosol splitter through a 10mm clamping sleeve, six aerosol splitter outlets 2-2 are respectively connected with a sample gas inlet 3-1 of a secondary diluter, a three-way filter membrane support 4-1, a high-efficiency filter VI 5-1 of a bypass gas unit and an online measurement unit 6.
The second-stage diluter 3 is provided with two air inlets and two air outlets, namely a second-stage diluter sample gas inlet 3-1, a second-stage diluter dilution gas inlet 3-2, a second-stage diluter excess gas outlet 3-3 and a second-stage diluter sample gas outlet 3-4. The sample gas inlet 3-1 of the secondary diluter is connected with one of the outlets in the splitter outlet 2-2, the sample gas inlet 3-2 of the secondary diluter, the redundant gas outlet 3-3 of the secondary diluter and the adjustable fan 3-8 form a closed-loop gas circuit, the flow of the two is equal, the flow of the sample gas outlet 4-4 of the secondary diluter and the flow of the sample gas inlet 4-1 of the secondary diluter are ensured to be equal, and the dilution ratio of the secondary diluter 4 can be adjusted by adjusting the ratio of the two flows. The flow direction of the closed-loop gas circuit is 3-3 of an excess gas outlet of the secondary diluter, and the closed-loop gas circuit is connected to 3-2 of a dilution gas inlet of the secondary diluter through 3-5 of a high-efficiency filter III, 3-6 of a temperature, humidity and pressure module II, 3-7 of a mass flow meter II, 3-8 of an adjustable fan and 3-9 of a high-efficiency filter IV.
The filter membrane collecting unit 4 comprises three filter membrane supports 4-1 which are respectively connected with three outlets of six splitter outlets 2-2, a connecting pipeline is a conductive silica gel hose, the outlets of the filter membrane supports 4-1 are connected with the inlet of a proportional valve 4-2, the outlet of the proportional valve 4-2 is connected with an efficient filter V4-3 to strengthen protection on a flow limiting hole I4-4, and the air path of the flow limiting hole I4-4 is connected to a vacuum pump 4-5 after being converged. The method has two operation modes, namely, three filter membranes sample simultaneously and are synchronously opened and closed; and secondly, the filter membrane sequential sampling is carried out by opening different filter membranes according to different stages of combustion, and the channel needing to be closed closes the proportional valve. 47mm quartz filter membranes or Teflon filter membranes can be placed on the filter membrane holders, the flow rate of each path is set to be 2.5L/min, and the flow rate is controlled in a compensation type flow limiting and controlling mode. When the particulate matter was gathered to the filter membrane, along with the particulate matter enrichment on the filter membrane, the pressure drop crescent that the air current produced through the filter membrane sets for the pressure differential scope that compensatory restricted orifice can compensate according to the maximum value that the pressure drop set for, avoids ordinary restricted orifice to produce the pressure drop crescent along with the filter membrane, problem that volume flow reduces gradually. The compensation method comprises the steps of monitoring the pressure difference between the outlet 2-2 of the flow divider and the pressure difference in front of each flow limiting hole I4-4 in real time, tightening the proportional valve 4-2 in an initial state, and compensating the pressure drop of the filter membrane by loosening the proportional valve 4-2 along with the gradual increase of the pressure drop of the filter membrane.
The bypass air unit 5 controls flow in a flow limiting hole mode, comprises a high-efficiency filter 5-1 and a flow limiting hole II 5-2 and is used for balancing flow used by instruments of other parts, the total flow of an outlet of the cyclone flow dividing unit 3 is 10L/min, and when the instruments used by a system are newly added or reduced or the flow used by parts of instruments or units in the system is changed, the flow can be balanced in a mode of replacing the flow limiting hole II 5-2. The flow limiting hole I4-4 and the flow limiting hole II 5-2 are connected to the same vacuum pump 4-5, and an absolute pressure measuring port is arranged in front of the vacuum pump 4-5 to ensure that the flow limiting holes are in a limiting flow limiting state.
The online measurement unit comprises an online measurement unit I6 and an online measurement unit II 7. Can be used to carry out the on-line measuring to civilian combustion source emission pollutant concentration, on-line measuring unit I6 is located one-level diluter back, connects one of them in six shunt exports, can dispose the instrument that gas monitoring appearance, PM2.5 mass concentration monitor, black carbon monitor etc. are fit for the high concentration and measure the occasion. The PM2.5 mass concentration monitor can correct the light heat dissipation signal by using the weighing result of the filter membrane. And the online measurement unit II7 is positioned behind the secondary diluter and can be configured with instruments such as a scanning particle size spectrometer and a particle mass spectrometer for low-concentration particle measurement occasions.
The specific working flow of the dilution sampling system is as follows:
1. erecting an instrument, placing a primary diluter 1 at a civil combustion source exhaust outlet, measuring the smoke temperature by a smoke temperature sensor 1-2, and adjusting the temperature of the diluter I1-1 in time by a temperature control module 1-4 until the temperature is stable;
2. and calculating the flow of each part to balance the flow of the system, wherein the unit of the flow is uniformly defined as L/min, and the flow is converted into the volume flow at the ambient atmospheric temperature. The following relationships apply:
dilution ratio of the primary diluter:
DR1 ═ Q1+ Q2)/Q1 (formula 1)
Dilution ratio of the second diluter
DR2 ═ Q7+ Q9)/Q7 (formula 2)
The flow balance relationship is as follows:
q1+ Q2 ═ Q3+ Q4+ Q5+ Q6+ Q7+ Q8 (formula 3)
Wherein:
q1 flue gas flow
Q2 flow of dilution gas of primary diluter
Q3, Q4, Q5: the volume flow at the support of the three filter membrane membranes is generally equal to that of the three filter membrane membranes
Q6 on-line measurement of Total flow of Unit I
Q7 on-line measurement of Total flow in Unit II
Q8 bypass gas Unit flow
Q9 flow of dilution gas of two-stage diluter
The left side in equation 3 is the total flow at the inlet of the cyclone unit, which should be close to 10.0L/min, so that the cyclone cutter achieves the optimal effect, therefore Q2 can be set according to the dilution ratio DR 1.
The right side in formula 3 is the total flow of the outlet of the cyclone flow dividing unit, which should be close to 10.0L/min, when the filter membrane collecting unit works in the simultaneous sampling mode, Q3, Q4 and Q5 regulate and control the flow for the compensation type flow limiting hole, when the filter membrane collecting unit works in the sequential sampling mode, only one flow is regulated and controlled for the compensation type flow limiting hole at the same time, and the other two paths are set to have the flow of 0. The total flow can be made to approach the set value by adjusting the size of the flow restriction orifice of the bypass air unit.
When the flow rate Q7 used by the on-line measuring unit II7 is known, the value of Q9 can be set according to the desired dilution ratio DR 2.
3. After the flow of each path is set, firstly, starting a compression pump 1-10, and carrying out back flushing on a flue gas flow measuring module 1-3 by airflow;
4. then starting a vacuum pump 4-5 to start membrane sampling, and simultaneously starting other online instruments to start sampling
5. And (4) setting the sampling time to be up, or stopping sampling when the pressure drop of the filter membrane exceeds a preset value.
Finally, it should be pointed out that: the above examples are only intended to illustrate the technical solution of the present invention, and not to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. The utility model provides a civilian combustion source discharges pollutant and dilutes sampling system, including one-level diluter (1), whirlwind reposition of redundant personnel unit (2), second grade diluter (3), filter membrane acquisition unit (4), bypass gas unit (5), on-line measuring unit I (6) and on-line measuring unit II (7), a serial communication port, one-level diluter (1) are located the system front end and are close to combustion source discharge opening department, the temperature of system automatically regulated one-level diluter (1) is the same with the flue gas temperature in order to prevent the flue gas condensation, flue gas and dilution gas steadily converge in one-level diluter (1), and after the homogeneous mixing is realized through the contraction mixing hole, get into whirlwind reposition of redundant personnel unit (2) through the heat preservation opium rifle, whirlwind reposition of redundant personnel unit (2) cut the large granule thing and equally reposition of redundant personnel to the aerosol, the fluid of redundant personnel gets into filter membrane acquisition unit (4) respectively, An on-line measuring unit I (6), a secondary diluter (3) and a bypass gas unit (5), wherein,
the primary diluter (1) is used for thermal dilution and adopts a normal-pressure mixing mode;
the secondary diluter (3) is diluted at normal temperature in a way of closing a loop by using diluent gas;
the filter membrane acquisition unit (4) works in a simultaneous sampling mode or a sequential sampling mode, and the flow is controlled by adopting a compensation type restricted orifice method;
the online measurement unit I (6) realizes online measurement of high-concentration pollutants;
the online measurement unit II (7) realizes online measurement of low-concentration particulate pollutants;
the bypass air unit (5) controls the flow in a flow limiting hole mode to balance the flow used by other instruments.
2. The dilution sampling system for pollutants discharged by civil combustion sources as claimed in claim 1, wherein the primary diluter (1) comprises a diluter I (1-1), a smoke temperature sensor (1-2), a smoke flow measuring module (1-3), a temperature control module (1-4), a heat preservation smoke gun (1-5), a silica gel drying pipe (1-6), a high efficiency filter I (1-7), a temperature and humidity pressure module I (1-8), a mass flow meter I (1-9), a compression pump (1-10) and a high efficiency filter II (1-11), wherein,
the diluter I (1-1) is of a normal-pressure mixing structure, is positioned at the top end of the heat-preservation smoke gun (1-5) and is close to a civil combustion source exhaust outlet;
the smoke temperature sensor (1-2) is used for measuring the smoke temperature;
the flue gas volume flow measuring module (1-3) measures the volume flow of the flue gas;
the temperature control module (1-4) comprises a resistance heater and a thermistor temperature sensor, and the temperature control module (1-4) dynamically adjusts the temperature of the diluter I (1-1) according to the temperature measured by the smoke temperature sensor (1-2) so that the temperature of the diluter I and the temperature of the diluter I are the same;
the heat preservation smoke gun (1-5) is used for connecting the diluter I (1-1) and the cyclone flow dividing unit (2);
air entering from the silica gel drying pipes (1-6) sequentially passes through a high-efficiency filter I (1-7), a temperature and humidity pressure module I (1-8), a mass flow meter I (1-9), a compression pump (1-10) and a high-efficiency filter II (1-11) to obtain clean, dry and stable-flow dilution air, wherein the silica gel drying pipes (1-6) are used for drying the air, the high-efficiency filter I (1-7) is used for removing particulate matters in the air, and the temperature and humidity pressure module I (1-8) is used for measuring temperature, relative humidity and absolute pressure information of the dilution air; the mass flow meter I (1-9) is used for measuring the mass flow of the diluent gas, the outlet of the mass flow meter I (1-9) is connected with the inlet of the compression pump (1-10), and the outlet of the compression pump (1-10) is connected with the high-efficiency filter II (1-11);
flue gas enters the diluter I (1-1) from an inlet of the flue gas flow measuring module (1-3), diluent gas enters from the side of the diluter I (1-1), and the flue gas and the diluent gas which are both at the normal pressure level are converged at a closing opening of the diluter I (1-1).
3. The dilution sampling system for pollutants discharged by civil combustion sources as claimed in claim 2, wherein the diluter I (1-1) is made of stainless steel, the temperature control module (1-4) is fixedly installed on the surface of the diluter I (1-1), and the rest part is wrapped by heat insulation cotton;
the smoke temperature sensor (1-2) adopts a platinum resistance temperature sensor, and the temperature measuring range is-40 to +200 ℃;
the flue gas flow measuring module (1-3) is a stainless steel capillary tube, the inner diameter of the tube is 1.8mm, the length of the tube is 80mm, the measured flow range is 0.2-2.0L/min at normal temperature, the chamfer of the outlet end is designed to realize the stable confluence of the dilution gas and the flue gas, and the flow measurement adopts a mode of measuring the pressure difference at two ends of the capillary tube;
the temperature control range of the temperature control modules (1-4) is 0-100 ℃;
the heat-preservation smoke gun (1-5) adopts a double-layer stainless steel sleeve mode, heat-preservation cotton is wrapped in the middle of the heat-preservation smoke gun, the central stainless steel pipe is connected with the diluter I (1-1) in a clamping sleeve joint mode, stable transition from the smoke temperature to the atmospheric environment temperature is realized, the generation of condensed water is prevented, and the loss of particles in a pipeline is reduced;
the compression pump (1-10) adjusts the air flow by means of duty ratio adjustment, the adjusted flow range is 5-15L/min, the control main board continuously acquires mass flow information and temperature pressure information to calculate the volume flow of the diluent gas at the ambient temperature, and the dilution ratio range is 5:1-30: 1.
4. The dilution sampling system for pollutants discharged by civil combustion sources as in claim 3, wherein the cyclone flow dividing unit (2) comprises a cyclone cutter and an aerosol flow divider, the inlet of the cyclone cutter is connected to the outlet of the heat preservation smoke gun (1-5) by adopting a conductive silica gel hose, and the outlet of the cyclone cutter is connected to the inlet (2-1) of the flow divider by adopting a clamping sleeve; the aerosol splitter is provided with six splitter outlets (2-2) which are symmetrically distributed in a circumferential mode, and smoke enters from the splitter inlet (2-1) and reaches the six splitter outlets (2-2) respectively after 90-degree smooth turning is achieved inside the smoke.
5. The dilution sampling system for pollutants discharged by civil combustion sources as in claim 4, wherein the cyclone cutter has a cutting particle size of 2.5 microns and a corresponding flow rate of 10L/min; the splitter inlet (2-1) has an outside diameter of 10mm and is matched to the cyclone cutter, and the splitter outlet (2-2) has an outside diameter of 3/8 inches and 1/4 inches for each downstream modular unit.
6. The dilution sampling system for pollutants discharged by civil combustion sources as claimed in claim 4, wherein the secondary diluter (3) is provided with two air inlets and two air outlets, namely a secondary diluter sample gas inlet (3-1), a secondary diluter dilution gas inlet (3-2), a secondary diluter excess gas outlet (3-3) and a secondary diluter sample gas outlet (3-4), and the secondary diluter sample gas inlet (3-1) is connected with one of the splitter outlets (2-2); the second-stage diluter dilution gas inlet (3-2), the second-stage diluter excess gas outlet (3-3) and the adjustable fan (3-8) form a closed-loop gas path: gas flowing out of the redundant gas outlet (3-3) of the secondary diluter passes through a high-efficiency filter III (3-5), a temperature and humidity pressure module II (3-6), a mass flow meter II (3-7), an adjustable fan (3-8) and a high-efficiency filter IV (3-9), and finally flows into a diluent gas inlet (3-2) of the secondary diluter; the flow of the dilution gas inlet (3-2) of the secondary diluter and the flow of the redundant gas outlet (3-3) of the secondary diluter are equal to ensure that the flow of the sample gas outlet (3-4) of the secondary diluter is equal to the flow of the sample gas inlet (3-1) of the secondary diluter, the dilution ratio of the secondary diluter (3) is adjusted by adjusting the ratio of the two flows, and the adjustment range of the dilution ratio is 3:1-30: 1.
7. The civil combustion source pollutant dilution sampling system as claimed in claim 4, wherein the filter membrane collecting unit (4) comprises three parallel filter membrane collecting channels and a vacuum pump (4-5), each filter membrane collecting channel comprises a filter membrane holder (4-1), a proportional valve (4-2), a high-efficiency filter V (4-3) and a flow limiting hole I (4-4) which are connected together in sequence, wherein the filter membrane holder (4-1) is used for holding 47mm filter membranes, the inlet of each filter membrane holder (4-1) is connected with a splitter outlet (2-2) through a conductive silica gel hose, the outlet of the filter membrane holder (4-1) is connected with the inlet of the proportional valve (4-2), and the outlet of the proportional valve (4-2) is connected with the high-efficiency filter V (4-3) to control the flow limiting hole I (4-4) -4) performing enhanced protection, wherein gas paths of the three flow limiting holes I (4-4) are converged and then connected to a vacuum pump (4-5), the flow of a first filter membrane collecting channel is set to be 2.5L/min, and the filter membrane collecting unit (4) comprises two modes of simultaneous sampling and sequential sampling, wherein the simultaneous sampling mode is synchronous opening or closing of the three filter membrane collecting channels; the sequential sampling mode is that different filter membrane collecting channels are opened for sampling according to different stages of combustion, and the division of the different stages of combustion can be divided according to the results of the on-line measuring instrument I (6) or the on-line measuring instrument II (7), or divided according to the time interval of the combustion.
8. The civil combustion source emission pollutant dilution sampling system as claimed in claim 7, wherein the flow rate regulation mode of the filter membrane collection unit (4) is a compensation type flow limiting hole mode, when the filter membrane collects the particulate matters, the pressure drop generated by the airflow passing through the filter membrane gradually increases as the particulate matters are enriched on the filter membrane, the pressure difference value before the flow divider outlet (2-2) and each flow limiting hole I (4-4) is monitored, the proportional valve (4-2) is regulated to keep the pressure difference constant, the proportional valve (4-2) is regulated tightly in the initial state, and the filter membrane pressure drop is compensated by regulating the loose proportional valve (4-2) as the filter membrane pressure drop gradually increases.
9. The dilution sampling system for pollutants discharged by civil combustion sources as claimed in claim 4, wherein the bypass gas unit (5) comprises a high-efficiency filter VI (5-1) and a flow limiting hole II (5-2), and when instruments used by the system are newly added or reduced or the flow used by some part of instruments or units in the system is changed, the flow of the system is balanced in a mode of replacing the flow limiting hole II (5-2); the flow limiting hole I (4-4) and the flow limiting hole II (5-2) are connected to the same vacuum pump (4-5), and an absolute pressure measuring port is arranged in front of the vacuum pump (4-5) to ensure that the flow limiting holes are in a limiting flow limiting state.
10. The dilution sampling system for pollutants discharged by civil combustion sources as claimed in claim 7, wherein the online measurement unit I (6) is arranged behind the primary diluter (1) and is provided with a gas monitor and a PM (particulate matter)2.5Mass concentration monitor, black carbon monitor and/or other instruments suitable for high concentration measurement, PM2.5The mass concentration monitor corrects the light heat dissipation signal by using the weighing result of the filter membrane;
the online measurement unit II (7) is positioned behind the secondary diluter (3), and is provided with a scanning particle size spectrometer, a particle mass spectrum and/or other online measurement instruments for low-concentration particle measurement occasions;
the positions of the measuring instrument in the online measuring unit I (6) and the measuring instrument in the online measuring unit II (7) can be directly interchanged without influencing the flow balance of the system.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210252763.XA CN114646509A (en) | 2022-03-15 | 2022-03-15 | Dilution sampling system for pollutants discharged by civil combustion source |
Applications Claiming Priority (1)
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