CN103808685B - A kind of low-concentration flue gas infrared spectrum analyser based on Fourier transformation and detection method - Google Patents
A kind of low-concentration flue gas infrared spectrum analyser based on Fourier transformation and detection method Download PDFInfo
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- 239000003546 flue gas Substances 0.000 title claims abstract description 46
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 45
- 238000001514 detection method Methods 0.000 title claims abstract description 43
- 238000002329 infrared spectrum Methods 0.000 title claims abstract description 24
- 230000009466 transformation Effects 0.000 title claims abstract description 20
- 238000011426 transformation method Methods 0.000 title description 2
- 238000000034 method Methods 0.000 claims abstract description 17
- 230000008569 process Effects 0.000 claims abstract description 10
- 239000000356 contaminant Substances 0.000 claims abstract description 9
- 239000007789 gas Substances 0.000 claims description 96
- 238000010521 absorption reaction Methods 0.000 claims description 45
- 238000005259 measurement Methods 0.000 claims description 22
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 18
- 230000005616 pyroelectricity Effects 0.000 claims description 17
- 125000001475 halogen functional group Chemical group 0.000 claims description 15
- 230000008676 import Effects 0.000 claims description 12
- 238000005520 cutting process Methods 0.000 claims description 9
- 230000001678 irradiating effect Effects 0.000 claims description 9
- 229910052757 nitrogen Inorganic materials 0.000 claims description 9
- 238000001035 drying Methods 0.000 claims description 6
- 238000001914 filtration Methods 0.000 claims description 6
- 239000000463 material Substances 0.000 claims description 5
- 230000003287 optical effect Effects 0.000 claims description 5
- WSMQKESQZFQMFW-UHFFFAOYSA-N 5-methyl-pyrazole-3-carboxylic acid Chemical compound CC1=CC(C(O)=O)=NN1 WSMQKESQZFQMFW-UHFFFAOYSA-N 0.000 claims description 4
- 230000007935 neutral effect Effects 0.000 claims description 4
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- 101710144202 Probable soluble pyridine nucleotide transhydrogenase Proteins 0.000 description 10
- 101710165942 Soluble pyridine nucleotide transhydrogenase Proteins 0.000 description 10
- 238000005033 Fourier transform infrared spectroscopy Methods 0.000 description 9
- 238000004458 analytical method Methods 0.000 description 9
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 2
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- 238000001745 non-dispersive infrared spectroscopy Methods 0.000 description 2
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- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/3504—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing gases, e.g. multi-gas analysis
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N2021/3595—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light using FTIR
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Abstract
The invention belongs to the flue gas infrared on-line checking analyzers such as flue gas monitoring apparatus field, a kind of low concentration of NO based on Fourier's time-frequency conversion model.The low-concentration flue gas infrared spectrum analyser based on Fourier transformation of this patent, including cabinet, heat control unit, output display unit, data acquisition process unit, power supply, drainage filter, detection for gaseous contaminants unit；The infrared spectrum analyser of the Fourier transformation of the present invention, is not required to be equipped with specially the interferometer of costliness, and structure is simpler, therefore significantly reduces the cost of equipment；Whole system uses double beam photometer method so that the impact of measured value is significantly reduced by temperature, therefore the long-term working stability of analyzer is higher.The instrument response time, faster the detection time shortened, and improved instrumental sensitivity.
Description
Technical field
The invention belongs to the flue gas infrared on-line checking analyzers such as flue gas monitoring apparatus field, a kind of low concentration of NO based on Fourier's time-frequency conversion model.
Background technology
Existing Fourier transform infrared analyzer is typically the coherence's principle design according to light, is a kind of interference type spectral instrument.Utilizing Fourier transform infrared spectroscopy principle to measure in the operation of gas concentration, mainly completed by three steps: the first step, measure infrared interference figure, this figure is a kind of Time Domain Spectrum；Second step, carries out Fast Fourier Transform (FFT) calculating by computer, thus obtains the frequency domain spectra as function with wavelength or frequency, i.e. Fourier transform infrared spectroscopy figure this wave in time domain；3rd step, finds the characteristic absorption peak of gas to be measured and records peak height value or peak area (i.e. absorbance)；Finally according to Lambert-Bill law, acquisition gas concentration value to be measured can be calculated.Such as: the Chinese invention patent application of Application No. 201010520324.X discloses a kind of transformer oil immersion gas analysis system based on Fourier transform infrared spectrum quantitative analysis and analysis method thereof；Wherein, the method carrying out on-line quantitative analysis with the FTIS multicomponent gas to being separated from transformer oil has been stressed；Its analysis model built have employed BP neutral net, and computing is complex, and characteristic variable extraction quantity is more, and each concentration of component certainty of measurement is relatively low, is only suitable for analysis and the detection of the occasion that gas concentration wider range is wide, component kind is more.
Within 2012, rising, new edition GB13223-2003 " fossil-fuel power plant atmospheric pollutant emission standard " specifies: after desulphurization and denitration, the flue gas concentration such as NO must reach below 100mg/m3.The discharge of pollutant sources monitoring infrared analysis NDIR systems such as these nitric oxide NOs a lot of for China and the analytical instrument Stability and veracity when lower range is measured are had higher requirement.Owing to, under identical air chamber length, the resolution ratio of NO is less than H2The resolution ratio of O, so the infrared band of NDIR can be caused larger interference by the moisture in discharge flue gas, error is big, big shortcoming of drifting about to cause gas NO etc. to exist when measuring；It is difficult to the New emission standard requirement of competent country.
To this end, the most current more employing ultraviolet difference or Fourier's infrared analysis technology, solve the problems referred to above.The Typical Representative of these technology has: Cerex company of the U.S. uses the ultraviolet difference technology of DOAS, Fourier's infrared analysis technology of the FTIR that Finland GASMET uses, but DOAS ultraviolet difference technology, is typically only suitable for monitoring trace gas (ppb level)；FTIR Fourier's infrared analysis technology, measures system complex, needs the facilities such as supporting interferometer, and apparatus value is expensive, is typically not suitable for measuring continuously；At present, China's analysis is in various industrial enterprises such as electric power, iron and steel, cement, pollution sources operating mode complexity is various, all suffers from the difficult problem that pollutant measurement interference factor is many, there is " not acclimatized " and the phenomenon of " standard is not inconsistent " in the actual application of external flue gas monitoring instrument.
This patent is for (Ai Mosheng process control Co., Ltd of Ai Mosheng company；Emerson process management) detector based on Fourier transformation, detector models is, and: X-Stream-Core(includes support circuit plate: GA-CZFPOWER V0.1)；When carrying out gas detection, detector can be according to zero gas obtained, the calibrating gas spectral signal different with sample gas, conversion obtains spectrogram and the measurement result data of sample gas, this patent is according to the supporting applicable detection equipment of above-mentioned detector stand-alone development, exploitation is applicable to the monitor of domestic market and environmental protection standard, breaks the technical monopoly of offshore company.
Summary of the invention
For solving the problem of above-mentioned existence, the present invention provides the low-concentration flue gas infrared spectrum analyser of a kind of high accuracy, high-resolution, it is possible to the infrared spectrum analyser of the most existing adaptive detector based on Fourier transformation, and the technical solution used in the present invention is as follows:
The low-concentration flue gas infrared spectrum analyser based on Fourier transformation of this patent, including cabinet 1, heat control unit 2, output display unit 3, data acquisition process unit 4, power supply 5；Arranging flue gas pipeline in cabinet 1, drainage filter 6 is arranged on flue gas pipeline import, and flue gas pipeline is respectively provided with temperature sensor, pressure sensor, humidity sensor, lambda sensor 7, detection for gaseous contaminants unit 8；Described detection for gaseous contaminants unit 8 includes infrared light supply 10 and is arranged on photochopper thereafter, is followed successively by absorption cell 12 along light path arrangement, measures air chamber 13, filter 14, detection sensor 15 after photochopper；Absorption cell 12 sets absorption cell sample gas import 16 and absorption cell sample gas outlet 17, measure air chamber 13 and separate respectively sample cell 20, reference cell 21 along optical path direction, encapsulation neutral gas in reference cell 21, sample cell 20 sets sample cell sample gas import 18 and sample cell sample gas outlet 19, and absorption cell sample gas outlet 17 is connected with sample cell sample gas import 18；Described photochopper blocks directive sample cell 20, the infrared beam of reference cell 21 that infrared light supply 10 sends in turn；Detection sensor 15 is connected to detector 22.Detector 22 is the detector based on Fourier transformation of Ai Mosheng company, and detector models is, and: X-Stream-Core(includes support circuit plate: GA-CZFPOWER V0.1).
Described photochopper blocks the frequency of sample cell 20: 120Hz to 155Hz；Photochopper blocks the frequency of reference cell 21: 90Hz to 125Hz.
Described photochopper is specially chopper, chopper is by driving motor 23 and cutting halo 11 and form, cut the peripherally disposed measurement in position, halo 11 outer rim counter sample pond 20 STH 29, measure the opposite inner edge correspondence reference cell 21 position peripherally disposed reference STH 30 of STH, as shown in Figure 5；Drive motor 23 drive cuts halo rotate, discontinuity block directive sample cell 20, the infrared beam of reference cell 21 that infrared light supply 10 sends.
Described low-concentration flue gas infrared spectrum analyser based on Fourier transformation, drives motor 23 to drive the rotating speed cutting halo 11 rotation to be 1830 rpm, and rotational frequency is 30.5Hz, measures STH 29 and arranges 4 to 5, and reference STH 30 arranges 3 to 4.The rotational frequency cutting halo employing is 30.5Hz, staggers with power frequency 50Hz, can avoid Hz noise.
The length of described absorption cell 12 is preferably 100mm ~ 240mm.
Described detection sensor 15 is preferably pyroelectric infrared detector, by pyroelectricity element 24, electrode 25, external circuit wire 26, load 27, power supply 28 forms, pyroelectricity element 24 is arranged on filter 14 rear portion just to infrared light supply 10 position, electrode 25 lays respectively at pyroelectricity element 24 both sides, and after external circuit wire 26 series load 27, power supply 28, electrode 25 with pyroelectricity element 24 both sides is connected respectively.Wherein pyroelectricity element 24 is made up of lithium tantalate TaLiO3 material.
Use the detection method of above-mentioned analyzer, comprise the steps:
Step 1, calibrating gas are prepared: configuration quality concentration is NO or the CO calibrating gas of 100mg/m3, and surplus is nitrogen, to be measured；
Step 2, start preheating: infrared light supply 10 sends monochromatic light, and photochopper carries out shading to infrared light supply 10, produce and irradiate sample cell 20, the two-beam of reference cell 21 respectively；First light beam, for measuring side beam, passes sequentially through absorption cell 12, sample cell 20, filter 14 arrival detection sensor 15；Second light beam is reference side beam, arrives detection sensor 15 by absorption cell 12, reference cell 21, filter 14；
Step 3, zero gas correction: in analyzer, be passed through zero gas, select purity be the nitrogen N 2 of 99.999% as zero gas, be full of absorption cell 12 and sample cell 20 to zero gas；
Step 4, the zero gas beam signal obtained when recording the first light beam and the second light beam irradiating and detecting sensor 15, transmission is to detector 22；
Step 5, nitrogen N 2 are discharged；
Step 6, calibrating gas measure: calibrating gas is passed through low-concentration flue gas infrared spectrum analyser, and after drainage filter 6 filtration drying, calibrating gas is full of absorption cell 12 and sample cell 20；
Step 7, the calibrating gas beam signal obtained when recording the first light beam and the second light beam irradiating and detecting sensor 15, transmission is to detector 22；
Step 8, calibrating gas are discharged；
Step 9, sample gas are measured: sample gas is passed through low-concentration flue gas infrared spectrum analyser, and after drainage filter 6 filtration drying, sample gas is full of absorption cell 12 and sample cell 20；
Step 10, the sample gas beam signal obtained when recording the first light beam and the second light beam irradiating and detecting sensor 15, transmission is to detector 22；
Step 11, detector 22 output detections result.
According to above-mentioned low-concentration flue gas infrared detection method based on Fourier transformation, it is characterized in that: photochopper blocks infrared light supply, formed the first light beam for measure side beam, irradiation frequency be the 155Hz: the second light beam be reference side beam, irradiation frequency is 122Hz.
The infrared spectrum analyser of the Fourier transformation of the present invention, has a following innovation bright spot relative to existing Fourier's infrared spectrum analyser: 1) it is not required to be equipped with specially the interferometer of costliness, structure is simpler, therefore significantly reduces the cost of equipment；2) whole system uses double beam photometer method, after the primary signal measured with reference signal synthesis is carried out Fourier's time-frequency conversion technical finesse, by reference peak value and the comparison of measurement peak value, accurately calculate gas concentration value to be measured, break the conventional measurement mode of Fourier transform infrared analyzer；The metering system of this novelty makes temperature significantly reduce the impact of measured value, therefore the long-term working stability of analyzer is higher.3) the instrument response time is faster, and the detection time shortens, and improves instrumental sensitivity.
The present invention is applicable to the measurement of light concentration gas, and in particular for the measurement of low concentration of NO gas, utilize NO gas lower concentration values measures sensitivity and the sensitive absorption characteristics to infrared light thereof, one absorption cell of special increase；During measurement, allow infrared beam sequentially pass through absorption cell, sample cell and arrive detection sensor, so that the monochromatic light passed through can be allowed to be fully absorbed by NO gas, make transmissivity T entering detector acquisition after sample cell bigger, with solve gas concentration to be measured the lowest time, transmissivity T is relatively low, cannot accurately measure a difficult problem for gas lower concentration values, improves analyzer detectivity and ability that anti-multicomponent interferes.
The present invention utilizes the photochopper of particular design, integrates light splitting and two kinds of functions of signal time-frequency conversion, has three effects: the 1) light beam sending infrared light supply, the most periodically interdicts light source, makes infrared light become pulsed infrared radiation；2) infrared beam making single light source send becomes dual-beam, it is achieved the signal identical open and close time, reduces from measuring side to the interference the crosstalk and each component passage of reference side；Realization minimizes light drift and reduces the measurement time；3) time-frequency conversion modulation is carried out by detector 22 so that the signal that detector produces is AC signal, it is simple to amplifier amplifies, and improves the response time properties of detector simultaneously.This is the innovation bright spot being different from other common choppers.
The present invention uses dual-beam metric measurement, compare other optical measuring techniques, there is following obvious advantage: monitor, by reference light, the effect that light intensity changes and is corrected the impact changed at any time, can automatically eliminate the error caused by intensity of light source change, avoid the measure error caused due to power-supply fluctuation or light source ages, also eliminate amplifier gain change and optics and electronics components and parts to two unbalanced impacts of light path simultaneously, so that drift reduces, baseline straightening degree improves, and not variation with temperature and change, improve the stability of instrument.
Further, the detection sensor of the present invention uses pyroelectric infrared detector to substitute traditional miniflow pneumatic detector, can make full use of the outstanding advantages of this special pyroelectricity material of lithium tantalate (TaLiO3): time delay temperature coefficient is low, Heat stability is good etc..The pyroelectric infrared detector made by this material crystals, the size of current produced by pyroelectric effect is removed and is directly proportional to the radiant power of infrared light, also it is directly proportional to rate of temperature change, therefore can be used to detect the strong and weak and fast-changing radiation signal of incident radiation so that this detector is more suitable for needing the detection Fourier that electronic signal is highly sensitive, cost performance is higher to change infrared detecting device.
The industry that the present invention can be benefited has: refining, petrochemical industry and chemical treatment, metallurgical production, hardening heat process, natural gas produce and distribution, the measurement of inflammable mixture of gas, biotechnology, garbage loading embeading process, the analysis of boiler flue gas, power plant, process smelting furnace and incinerator, various places CEMS integrator and ring prison station etc..The present invention is except being suitable for the measurement of NO low-concentration flue gas, it is possible to be applied to the detection to flue gases such as low concentration CO.
Accompanying drawing explanation
Fig. 1 is the topology layout figure of embodiment of the present invention flue gas analyzer.
Fig. 2 is detection for gaseous contaminants cellular construction schematic diagram of the present invention.
Fig. 3 is detection for gaseous contaminants unit two-way arrangement schematic diagram of the present invention.
Fig. 4 is pyroelectric infrared detector structural representation (is perpendicular to pyroelectricity element 24 arrow and represents the incident direction of incident light).
Fig. 5 is for cutting halo structural representation.
Fig. 6 is the FTIR technique figure obtained after sample gas device 22 after testing processes.
Detailed description of the invention
Embodiment
1
:
Fig. 1 is the topology layout figure of embodiment of the present invention flue gas analyzer, as it can be seen, include cabinet 1, heat control unit 2, output display unit 3, data acquisition process unit 4, power supply 5；Arranging flue gas pipeline in cabinet 1, drainage filter 6 is arranged on flue gas pipeline import, and flue gas pipeline is respectively provided with temperature sensor, pressure sensor, humidity sensor, lambda sensor 7, detection for gaseous contaminants unit 8；Also including a flue gas measuring multiple parameters chamber 9 in cabinet, temperature sensor, pressure sensor, humidity sensor are arranged in flue gas measuring multiple parameters chamber 9.
The detection for gaseous contaminants unit 8 of the present embodiment, including Fig. 2 mid-infrared light source 10 and be arranged on photochopper thereafter, is followed successively by absorption cell 12 after chopper along light path arrangement, measures air chamber 13, filter 14, detection sensor 15；Absorption cell 12 sets absorption cell sample gas import 16 and absorption cell sample gas outlet 17, measures air chamber 13 and separate respectively sample cell 20, reference cell 21 along optical path direction；In reference cell 21, the neutral gas of encapsulation is high purity N2(99.999%).Sample cell 20 sets sample cell sample gas import 18 and sample cell sample gas outlet 19, and absorption cell sample gas outlet 17 is connected with sample cell sample gas import 18.The light beam that photochopper modulation infrared light supply 10 sends forms two monochromic beams, and a branch of entrance through absorption cell 12 measures air chamber 13, and another bundle enters reference cell 21 through absorption cell 12, and two monochromic beams irradiate above-mentioned each air chamber the most simultaneously.Detection sensor 15 is connected to detector 22.
Wherein, photochopper is specially a kind of chopper, and chopper is by driving motor 23 and cutting halo 11 and form.Cut the structure of halo 11 as shown in Figure 5.Halo 11 major function of cutting of the present invention is the light beam sending infrared light supply, by certain cycle cutting, infrared light is made to become pulsed infrared radiation, time-frequency conversion modulation is carried out by modulator 25, the signal that detector is produced is AC signal, and form two monochromic beams, irradiate the most simultaneously and pass reference cell and sample cell；Often set chopper can be simultaneously used for two groups of Infrared Detectors, to detect the value of two kinds of gas concentrations respectively.Wherein, motor 23 is driven to use eddy current dc motor, rotating speed n to be designed as 1830rpm, for this rotational frequency f0 =
n/60 =30.5Hz.Having measurement STH and reference STH on halo 11 cutting, its shape is based on sector, and hole count is preferably in the range of 3-5, in the range of therefore pulse signal frequency recommends f=30.5* (3～5)=100Hz 155Hz.Cut reference side opening number and measurement STH number on halo to change according to actual gaseous species to be measured.Such as, during Fig. 5 is shown, above plectane, circumferentially it is symmetrically distributed with 4 reference side openings and 5 measurement STHs；Reference light is passed by chopper 4 reference side openings, and each cycle can irradiate reference cell 4 times so that the measurement frequency of reference light is 4*30.5Hz=122Hz；Measuring light to be passed by chopper 5 measurement STHs, each cycle can irradiate sample cell 5 times so that measurement light frequency is 5*30.5Hz=152Hz.
A length of 100mm ~ the 240mm of the absorption cell 12 of the present invention, length selects to depend on gas concentration size to be measured；General gas concentration to be measured is the lowest, and absorption cell length is the longest, in order to monochromatic light can be allowed to be fully absorbed by the gas of certain wavelength, forms obvious absworption peak feature in spectrogram.
In the present invention, absorption cell 12 and measuring chamber 13 are managed and are all used cylindrical shape, and die encapsulant is all used at the two ends of cylinder.Measuring chamber 13 pipe uses sample cell 20 and reference cell 21 respectively to account for " monotubular is every partly " type structure of half.
Embodiment
2
:
Improvement as embodiment 1, the present embodiment is by the preferred pyroelectric infrared detector of detection sensor 15 in embodiment 1, structure includes pyroelectricity element 24 in Fig. 4, electrode 25, external circuit wire 26, load 27, power supply 28 forms, wherein, pyroelectricity element 24 is arranged on filter 14 rear portion just to optical path direction position, and electrode 25 lays respectively at pyroelectricity element 24 both sides, and after external circuit wire 26 series load 27, power supply 28, electrode 25 with pyroelectricity element 24 both sides is connected respectively.In technique scheme, pyroelectricity element 24 preferred lithium tantalate (TaLiO3) material is made, and other structures are same as in Example 1.
In Fig. 2, the monochromatic light that infrared light supply 10 sends, after chopper 11 is modulated, form two monochromic beams, a branch of sample cell 20 respectively enterd in absorption chamber 12 and measurement air chamber 13, another bundle passes through absorption chamber 12 and the reference cell 21 measured in air chamber 13 respectively.Owing to the molecule of the xenogenesis atomic buildings such as NO has absorption characteristic to light, if there is above-mentioned gas in absorption chamber 12 and measurement air chamber 13, then the part light entering above-mentioned two air chamber can be absorbed, and unabsorbed light enters detector 15 after filter 14.Pyroelectric infrared detector in detector respectively obtains through the spectral signal after reference cell and sample cell, the detector 22 of spectral signal transmission to Ai Mosheng.By the computer in detector 22, above-mentioned spectral signal carried out fast Fourier time-frequency conversion, thus obtain concentration value in testing sample Fourier transform infrared spectroscopy figure quantitative analysis flue gas.Fig. 6 is the FTIR technique figure obtained after sample gas device 22 after testing processes, wherein 40 is reference side peak value, 41 for measuring side peak value, owing to photochopper blocks infrared light supply, the first light beam formed is for measuring side beam, and irradiation frequency is 155Hz, and the second light beam is reference side beam, irradiation frequency is 122Hz, therefore forms the spectrogram that peak value staggers in Fig. 6.
Embodiment
3
:
Use the detection method of the analyzer of embodiment 1, it is characterised in that comprise the steps:
Step 1, calibrating gas are prepared: configuration quality concentration is NO or the CO calibrating gas of 100mg/m3, and surplus is nitrogen, to be measured；
Step 2, start preheating: infrared light supply (10) sends monochromatic light, and photochopper carries out shading to infrared light supply (10), produces and irradiates sample cell (20), the two-beam of reference cell (21) respectively；First light beam, for measuring side beam, passes sequentially through absorption cell (12), sample cell (20), filter (14) arrival detection sensor (15)；Second light beam is reference side beam, arrives detection sensor (15) by absorption cell (12), reference cell (21), filter (14)；
Step 3, zero gas correction: in analyzer, be passed through zero gas, select purity be the nitrogen N 2 of 99.999% as zero gas, be full of absorption cell (12) and sample cell (20) to zero gas；
Step 4, the zero gas beam signal obtained when recording the first light beam and the second light beam irradiating and detecting sensor (15), transmit to detector (22)；
Step 5, nitrogen N 2 are discharged；
Step 6, calibrating gas measure: calibrating gas is passed through low-concentration flue gas infrared spectrum analyser, and after drainage filter (6) filtration drying, calibrating gas is full of absorption cell (12) and sample cell (20)；
Step 7, the calibrating gas beam signal obtained when recording the first light beam and the second light beam irradiating and detecting sensor (15), transmit to detector (22)；
Step 8, calibrating gas are discharged；
Step 9, sample gas are measured: sample gas is passed through low-concentration flue gas infrared spectrum analyser, and after drainage filter (6) filtration drying, sample gas is full of absorption cell (12) and sample cell (20)；
Step 10, the sample gas beam signal obtained when recording the first light beam and the second light beam irradiating and detecting sensor (15), transmit to detector (22)；
Step 11, detector (22) output detections result.
Claims (9)
1. a low-concentration flue gas infrared spectrum analyser based on Fourier transformation, including cabinet (1), heat control unit (2), output display unit (3), data acquisition process unit (4), power supply (5)；Arranging flue gas pipeline in cabinet (1), drainage filter (6) is arranged on flue gas pipeline import, and flue gas pipeline is respectively provided with temperature sensor, pressure sensor, humidity sensor, lambda sensor (7), detection for gaseous contaminants unit (8)；It is characterized in that: described detection for gaseous contaminants unit (8) includes infrared light supply (10) and is arranged on photochopper thereafter, after photochopper, be followed successively by absorption cell (12) along light path arrangement, measure air chamber (13), filter (14), detection sensor (15)；Absorption cell (12) sets absorption cell sample gas import (16) and absorption cell sample gas outlet (17), measure air chamber (13) and separate respectively sample cell (20), reference cell (21) along optical path direction, encapsulation neutral gas in reference cell (21), sample cell (20) sets sample cell sample gas import (18) and sample cell sample gas outlet (19), and absorption cell sample gas outlet (17) is connected with sample cell sample gas import (18)；Described photochopper blocks directive sample cell (20), the infrared beam of reference cell (21) that infrared light supply (10) sends in turn；Detection sensor (15) is connected to detector (22).
Low-concentration flue gas infrared spectrum analyser based on Fourier transformation the most according to claim 1, it is characterised in that: described photochopper blocks the frequency of sample cell (20) and is: 120Hz to 155Hz；Photochopper blocks the frequency of reference cell (21): 90Hz to 125Hz.
Low-concentration flue gas infrared spectrum analyser based on Fourier transformation the most according to claim 1, it is characterized in that: described photochopper is specially chopper, chopper is by driving motor (23) and cutting halo (11) and form, cut halo (11) the outer rim counter sample peripherally disposed measurement in pond (20) position STH (29), measure opposite inner edge correspondence reference cell (21) position peripherally disposed reference STH (30) of STH, drive motor (23) to drive and cut halo rotation, discontinuity block the directive sample cell (20) that infrared light supply (10) sends, the infrared beam of reference cell (21).
Low-concentration flue gas infrared spectrum analyser based on Fourier transformation the most according to claim 3, it is characterized in that: driving motor (23) to drive, to cut the rotating speed that halo (11) rotates be 1830 rpm, rotational frequency is 30.5Hz, measuring STH (29) and arrange 4 to 5, reference STH (30) arranges 3 to 4.
Low-concentration flue gas infrared spectrum analyser based on Fourier transformation the most according to claim 1, it is characterised in that: a length of 100mm ~ 240mm of absorption cell (12).
Low-concentration flue gas infrared spectrum analyser based on Fourier transformation the most according to claim 1, it is characterized in that: described detection sensor (15) is pyroelectric infrared detector, by pyroelectricity element (24), electrode (25), external circuit wire (26), load (27), power supply (28) forms, pyroelectricity element (24) is arranged on filter (14) rear portion just to infrared light supply (10) position, electrode (25) lays respectively at pyroelectricity element (24) both sides, external circuit wire (26) series load (27), after power supply (28), electrode (25) with pyroelectricity element (24) both sides is connected respectively.
Low-concentration flue gas infrared spectrum analyser based on Fourier transformation the most according to claim 6, it is characterised in that: pyroelectricity element (24) is made up of lithium tantalate material.
8. the detection method of the low-concentration flue gas infrared spectrum analyser based on Fourier transformation used described in claim 1, it is characterised in that comprise the steps:
Step 1, calibrating gas are prepared: configuration quality concentration is 100mg/m3NO or CO calibrating gas, surplus is nitrogen, to be measured；
Step 2, start preheating: infrared light supply (10) sends monochromatic light, and photochopper carries out shading to infrared light supply (10), produces and irradiates sample cell (20), the two-beam of reference cell (21) respectively；First light beam, for measuring side beam, passes sequentially through absorption cell (12), sample cell (20), filter (14) arrival detection sensor (15)；Second light beam is reference side beam, arrives detection sensor (15) by absorption cell (12), reference cell (21), filter (14)；
Step 3, zero gas correction: in analyzer, be passed through zero gas, select purity be the nitrogen of 99.999% as zero gas, be full of absorption cell (12) and sample cell (20) to zero gas；
Step 4, the zero gas beam signal obtained when recording the first light beam and the second light beam irradiating and detecting sensor (15), transmit to detector (22)；
Step 5, nitrogen are discharged；
Step 6, calibrating gas measure: calibrating gas is passed through low-concentration flue gas infrared spectrum analyser, and after drainage filter (6) filtration drying, calibrating gas is full of absorption cell (12) and sample cell (20)；
Step 7, the calibrating gas beam signal obtained when recording the first light beam and the second light beam irradiating and detecting sensor (15), transmit to detector (22)；
Step 8, calibrating gas are discharged；
Step 9, sample gas are measured: sample gas is passed through low-concentration flue gas infrared spectrum analyser, and after drainage filter (6) filtration drying, sample gas is full of absorption cell (12) and sample cell (20)；
Step 10, the sample gas beam signal obtained when recording the first light beam and the second light beam irradiating and detecting sensor (15), transmit to detector (22)；
Step 11, detector (22) output detections result.
Low-concentration flue gas infrared detection method based on Fourier transformation the most according to claim 8, it is characterized in that: photochopper blocks infrared light supply, formed the first light beam for measure side beam, irradiation frequency be the 155Hz: the second light beam be reference side beam, irradiation frequency is 122Hz.
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| CN107957405A (en) * | 2018-01-11 | 2018-04-24 | 太原海纳辰科仪器仪表有限公司 | A kind of portable infrared flue gas analyzer |
| CN111141693A (en) * | 2020-02-20 | 2020-05-12 | 彭忠祥 | In-situ continuous detection system for content of metal elements in water |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1164775A (en) * | 1967-08-03 | 1969-09-24 | Hartmann & Braun Ag | Improvements in or relating to a selective twin-beam infra-red gas analyser |
| GB1256010A (en) * | 1965-09-01 | 1971-12-08 | Mine Safety Appliances Co | Infra-red gas analyser unit |
| US4549080A (en) * | 1983-06-17 | 1985-10-22 | Infrared Industries, Inc. | Double-pass flue gas analyzer |
| CN2237240Y (en) * | 1995-04-03 | 1996-10-09 | 吉林大学 | Infrared gas analysing instrument without gas room |
| CN201331493Y (en) * | 2008-12-31 | 2009-10-21 | 北京市华云分析仪器研究所有限公司 | Infrared gas analyzer |
| CN101726468A (en) * | 2009-12-11 | 2010-06-09 | 宇星科技发展(深圳)有限公司 | Nox analyzer |
| CN201707286U (en) * | 2010-05-12 | 2011-01-12 | 重庆川仪分析仪器有限公司 | Novel light cutting sheet, and light source generator and infrared gas analyzer |
| CN102183482A (en) * | 2011-02-23 | 2011-09-14 | 中国科学院安徽光学精密机械研究所 | Non-disperse infrared multi-component flue gas analyzer |
| CN102439424A (en) * | 2009-05-19 | 2012-05-02 | 西门子公司 | Ndir-two beam gas analyser and method for determining the concentration of a measuring gas component in a gas mixture by means of said type of gas analyser |
| CN102713566A (en) * | 2009-12-22 | 2012-10-03 | 西门子公司 | NDIR dual trace gas analyzer and method for determining the concentration of a measurement gas component in a gas mixture by means of such a gas analyzer |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09178656A (en) * | 1995-12-26 | 1997-07-11 | Shimadzu Corp | Infrared gas analyzer |
| CN102252991A (en) * | 2011-06-03 | 2011-11-23 | 天津市蓝宇科工贸有限公司 | Ultraviolet differential flue gas concentration monitoring system through heat and moisture extraction process |
-
2012
- 2012-11-14 CN CN201210455662.9A patent/CN103808685B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1256010A (en) * | 1965-09-01 | 1971-12-08 | Mine Safety Appliances Co | Infra-red gas analyser unit |
| GB1164775A (en) * | 1967-08-03 | 1969-09-24 | Hartmann & Braun Ag | Improvements in or relating to a selective twin-beam infra-red gas analyser |
| US4549080A (en) * | 1983-06-17 | 1985-10-22 | Infrared Industries, Inc. | Double-pass flue gas analyzer |
| CN2237240Y (en) * | 1995-04-03 | 1996-10-09 | 吉林大学 | Infrared gas analysing instrument without gas room |
| CN201331493Y (en) * | 2008-12-31 | 2009-10-21 | 北京市华云分析仪器研究所有限公司 | Infrared gas analyzer |
| CN102439424A (en) * | 2009-05-19 | 2012-05-02 | 西门子公司 | Ndir-two beam gas analyser and method for determining the concentration of a measuring gas component in a gas mixture by means of said type of gas analyser |
| CN101726468A (en) * | 2009-12-11 | 2010-06-09 | 宇星科技发展(深圳)有限公司 | Nox analyzer |
| CN102713566A (en) * | 2009-12-22 | 2012-10-03 | 西门子公司 | NDIR dual trace gas analyzer and method for determining the concentration of a measurement gas component in a gas mixture by means of such a gas analyzer |
| CN201707286U (en) * | 2010-05-12 | 2011-01-12 | 重庆川仪分析仪器有限公司 | Novel light cutting sheet, and light source generator and infrared gas analyzer |
| CN102183482A (en) * | 2011-02-23 | 2011-09-14 | 中国科学院安徽光学精密机械研究所 | Non-disperse infrared multi-component flue gas analyzer |
Non-Patent Citations (2)
| Title |
|---|
| 在线红外气体分析器的发展及工程应用研究;姜培刚;《分析仪器》;20091231(第6期);第77-86页 * |
| 非分散红外多组分气体检测技术及其在CEMS中的应用;孙友文 等;《红外》;20110531;第32卷(第5期);第23-26页 * |
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