CN117269007A - Forward scattering detector for measuring concentration of particulate matters in high-temperature flue gas - Google Patents
Forward scattering detector for measuring concentration of particulate matters in high-temperature flue gas Download PDFInfo
- Publication number
- CN117269007A CN117269007A CN202311173539.2A CN202311173539A CN117269007A CN 117269007 A CN117269007 A CN 117269007A CN 202311173539 A CN202311173539 A CN 202311173539A CN 117269007 A CN117269007 A CN 117269007A
- Authority
- CN
- China
- Prior art keywords
- measuring
- light source
- sample gas
- mounting seat
- flue gas
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 27
- 239000003546 flue gas Substances 0.000 title claims abstract description 27
- 239000007789 gas Substances 0.000 claims abstract description 61
- 230000003287 optical effect Effects 0.000 claims abstract description 49
- 238000005259 measurement Methods 0.000 claims abstract description 20
- 239000002245 particle Substances 0.000 claims abstract description 14
- 230000001154 acute effect Effects 0.000 claims abstract description 4
- 238000010438 heat treatment Methods 0.000 claims description 8
- 239000013618 particulate matter Substances 0.000 claims description 4
- 238000010926 purge Methods 0.000 description 10
- 238000012544 monitoring process Methods 0.000 description 9
- 239000000779 smoke Substances 0.000 description 6
- 108010085603 SFLLRNPND Proteins 0.000 description 4
- 238000012423 maintenance Methods 0.000 description 4
- 238000001514 detection method Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000013307 optical fiber Substances 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 238000000790 scattering method Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 230000009897 systematic effect Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume, or surface-area of porous materials
- G01N15/06—Investigating concentration of particle suspensions
-
- 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
- G01N21/47—Scattering, i.e. diffuse reflection
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
Abstract
The invention discloses a front scattering detector for measuring the concentration of high-temperature flue gas particles, which comprises a seat body, wherein a measuring cavity is arranged in the seat body, a measuring light path and a calibration light path are arranged in the seat body, a sample gas inlet is arranged at the top of the seat body, and a sample gas outlet is arranged at the bottom of the seat body; the measuring light path comprises a measuring light source, a first optical element assembly and a photoelectric receiver, the measuring light source is connected with the base through a first mounting seat, the calibrating light path comprises a calibrating light source and a second optical element assembly, the calibrating light source is connected with the base through a second mounting seat, the photoelectric receiver is located on the optical axis of the calibrating light source, the optical axis of the calibrating light source intersects with the optical axis of the measuring light source and the axis of the sample gas inlet at one point, and an included angle between the first mounting seat and the second mounting seat is an acute angle. The invention has simple structure, can realize measurement and calibration without moving parts, and meets the working condition of high-temperature and high-humidity flue gas measurement.
Description
Technical Field
The invention relates to a flue gas measurement technology, in particular to a front scattering detector for measuring the concentration of high-temperature flue gas particles.
Background
In the flue gas emission monitoring, the state of flue gas is gradually converted to a low-temperature high-humidity state, so that the accuracy requirement for measuring the particulate matters in the flue gas is a great test, the sensitivity requirement on a detector is high, and the stability and convenience requirements on a monitoring system are higher and higher.
In conventional flue gas emission monitoring, the detector unit structure is mostly incapable of measuring high temperature flue gas. At present, the smoke emission monitoring systems of some factories can measure high-temperature smoke, but the system structures are complex, for example, the light paths of the smoke emission monitoring systems are all connected by optical fibers or quartz light guide columns, the reliability is poor and the smoke emission monitoring systems are easy to damage, and the light paths are required to be switched by a light path switching mechanism (usually a rotating seat) during calibration. The light path switching unit is required to be installed in the detection area, so that the detection unit of the system is large in size, the flue gas extraction system is large in size, and transportation and installation are limited.
Disclosure of Invention
In order to solve the defects in the prior art, the invention aims to provide the front scattering detector for measuring the concentration of the high-temperature flue gas particles, which has a simple structure, can realize measurement and calibration without moving parts, and meets the working condition of high-temperature and high-humidity flue gas measurement.
The technical scheme adopted for solving the technical problems is as follows: the front scattering detector for measuring the concentration of the high-temperature flue gas particles comprises a base body, wherein a measuring cavity is arranged in the base body, a measuring light path and a calibrating light path are arranged in the base body, a sample gas inlet is formed in the top of the base body, and a sample gas outlet is formed in the bottom of the base body;
the measuring light path comprises a measuring light source, a first optical element assembly and a photoelectric receiver, wherein the measuring light source is connected with the base body through a first mounting seat, a first light channel is arranged in the first mounting seat, and the first optical element assembly is arranged in the first light channel;
the calibration light path comprises a calibration light source and a second optical element assembly, the calibration light source is connected with the base body through a second mounting seat, a second optical channel is arranged in the second mounting seat, and the second optical element assembly is arranged in the second optical channel;
the photoelectric receiver is positioned on the optical axis of the calibration light source, the optical axis of the calibration light source intersects with the optical axis of the measurement light source and the axis of the sample gas inlet at one point, and an included angle between the first mounting seat and the second mounting seat is an acute angle.
Optionally, an optical trap is further installed in the base, and the optical trap is located on the optical axis of the measuring light source.
Optionally, the seat body is provided with an upper cover at the position of the sample gas inlet, and is provided with an air curtain assembly around the sample gas inlet, and the air curtain assembly is communicated with the measurement cavity;
the middle part of upper cover is equipped with the sample gas passageway that is linked together with the sample gas entry, the lateral part of upper cover is equipped with the sweep gas entry that lets in sweep gas to constitute the sweep gas passageway that sweep gas flows between the inner wall of upper cover and the outer wall of sample gas passageway, sweep gas passageway and gas curtain subassembly switch-on.
Optionally, the air curtain assembly includes small holes around the sample gas inlet, the small holes are circumferentially arranged around the sample gas inlet, and the diameter of the small holes is 1.5-2.1 mm.
Optionally, a heating unit is installed in the measurement cavity, and the heating unit heats the measurement cavity, so that the temperature in the measurement cavity is kept at 140-155 ℃.
By adopting the technical scheme, compared with the prior art, the invention has the following beneficial effects:
1. the invention has simple light path structure and ingenious structure, and can effectively complete measurement and automatic calibration without moving parts.
2. The optical path in the measuring cavity is short, interference factors are few, and the detection precision can be improved.
3. The device is provided with the purge gas, so that the window sheets are effectively prevented from being polluted by flue gas, adjustment is not needed after disassembly, assembly and maintenance, the consistency is good, and the problems of frequent maintenance and complicated maintenance and adjustment of the traditional detector are effectively solved.
Drawings
FIG. 1 is a schematic diagram of the structure of the present invention;
FIG. 2 is a schematic view of the structure of the air curtain assembly of the present invention;
fig. 3 is a cross-sectional view of the present invention.
Detailed Description
The present application is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be noted that, for convenience of description, only the portions related to the invention are shown in the drawings.
It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.
As shown in fig. 1, the invention discloses a front scattering detector for measuring the concentration of high-temperature flue gas particles, which comprises a base 17, wherein the base 17 is a main body part of the detector, a measuring cavity is arranged in the base 17, and when flue gas is detected, the flue gas enters the measuring cavity. A measuring light path and a calibrating light path are arranged in the seat body 17, a sample gas inlet is arranged at the top of the seat body 17, and a sample gas outlet is arranged at the bottom of the seat body 17 so as to facilitate the flue gas to enter and exit the measuring cavity.
In the invention, the measuring light path comprises a measuring light source 20, a first optical element assembly and a photoelectric receiver 2, wherein the measuring light source 20 is connected with a base 17 through a first mounting seat 15, the measuring light source 20 is fixedly arranged at one end part of the first mounting seat 15 far away from the base 17 through a measuring light source connecting seat 8 and a measuring light source shell 14, a first light channel is arranged in the first mounting seat 15, the first optical element assembly is arranged in the first light channel, light emitted by the measuring light source 20 penetrates through the first optical element assembly in the first light channel and enters a measuring cavity, and irradiates on the surface of particles to be scattered, the scattered light is received by the photoelectric receiver 2, and a received light signal is transmitted to a smoke monitoring system by the photoelectric receiver 2 to be analyzed, so that the concentration of the particles is obtained. Specifically, the photoelectric receiver 2 is connected to the base 17 by the receiver mounting base 12, the optical cavity 3 is disposed in front of the photoelectric receiver 2, an included angle is formed between the receiving optical axis of the photoelectric receiver 2 and the axis of the first mounting base 15, and the included angle can be set to be an obtuse angle, for example, 135 °, by which the arrangement of the calibration optical path can be facilitated. In addition, an optical trap 9 may be installed inside the base 17, and the optical trap 9 is used to eliminate stray light of the measuring light source 20, so as to improve the measuring accuracy. The first optical element assembly specifically comprises a first plano-convex lens 4-3, a first wedge-shaped lens 6-1, a first diaphragm 7-1 and a focusing lens, wherein the first plano-convex lens 4-3, the first wedge-shaped lens 6-1, the first diaphragm 7-1 and the focusing lens are sequentially arranged in the first optical channel from the measuring cavity to the direction of the measuring light source 20, and after the light emitted by the measuring light source 20 is focused and collimated by the front focusing lens, stray light is shielded by the first diaphragm 7-1 with the path of 5mm, and then the stray light is shaped into parallel light by the first wedge-shaped lens 6-1 and the first plano-convex lens 4-3 in sequence and irradiates the surface of particles. At the front stage of the photo receiver 2, a second plano-convex lens 4-2 and a third plano-convex lens 4-1 are also mounted.
In the present invention, the calibration light path includes a calibration light source 21 and a second optical element assembly, the calibration light source 21 is connected to the base 17 through the second mount 16, and a second optical channel is provided in the second mount 16, and the second optical element assembly is mounted in the second optical channel. Specifically, the calibration light source housing 11 of the calibration light source 21 is fixedly connected with the second mounting seat 16, the second optical element assembly specifically comprises a second wedge-shaped lens 6-2, a second diaphragm 7-2, a third diaphragm 7-3 and a light guide column 23, the power of the photodiode 24 of the calibration light source 21 can be 5mw, the emitted light wavelength is 650nm, the emitted light beam is uniformly transmitted through the light guide column 23, then stray light is shielded through the second diaphragm 7-2 and the third diaphragm 7-3, and the shaped light enters the measurement cavity through the second wedge-shaped lens 6-2.
In the present invention, the optical axis of the calibration light source 21 intersects the optical axis of the measurement light source 20 and the axis of the sample gas inlet at a point, and the included angle between the first mounting seat 15 and the second mounting seat 16 is an acute angle.
In addition, in the present invention, the seat 17 is provided with an upper cover 18 at the sample gas inlet position, the upper cover 18 is connected with the seat 17 through the cover plate 13, and the seat 17 is provided with an air curtain assembly 19 around the sample gas inlet, and the air curtain assembly 19 communicates with the measurement cavity. Specifically, a sample gas channel 1 connected to the sample gas inlet is provided in the middle of the upper cover 18, a purge gas inlet 22 for introducing purge gas is provided in the side of the upper cover 18, and a purge gas channel for flowing purge gas is formed between the inner wall of the upper cover 18 and the outer wall of the sample gas channel 1, and the purge gas channel is connected to the gas curtain assembly 19.
The air curtain assembly 19 comprises small holes arranged around the sample gas inlet, the small holes are circumferentially arranged around the sample gas inlet, and the diameter of the small holes is 1.5-2.1 mm. While introducing flue gas into the sample gas channel 1, introducing purge gas from the purge gas inlet 22 to keep the purge gas at a pressure of 0.35MPa and a flow of 25L/min, and then introducing the purge gas into the measurement cavity through the gas curtain assembly 19 to keep a laminar flow state with the sample gas, thereby preventing the sample gas from flowing to the position of the window and keeping the window clean.
In the invention, a heating unit is also arranged in the measuring cavity, and the heating unit heats the measuring cavity, so that the temperature in the measuring cavity is kept at 140-155 ℃. Specifically, the heating unit includes heating rod 10 and temperature sensor 5, and temperature sensor 5 is connected with the flue gas monitoring system.
The invention measures the concentration of the particles by utilizing a laser front scattering method, 650nm laser red light is used as a measuring light source 20, modulated laser passes through a measuring area and is applied to an optical trap 9, the optical trap 9 absorbs a part of main light spots and reflects a part of main light spots to a non-receiving area, the measuring light source 20 irradiates the particles to generate scattered light when passing through the measuring area and receives the scattered light by a photoelectric receiver 2 to generate an electric signal, the electric signal is subjected to signal blocking, amplifying and AD conversion and then is applied to a smoke monitoring system to calculate the concentration of the particles, and the size of a signal X of the photoelectric receiver 2 is in direct proportion to the concentration Y of the particles in the measuring area.
When the measuring area has no particulate matters, the light path is caused by stray light, the generated signal is the background B of the whole detecting unit, and the background is deducted at the initial power-on or periodically, so that the automatic zero calibration can be realized, the manual intervention is not needed, and the maintenance quantity is reduced. The particulate matter concentration expression is y=kx-B.
The calibration light path is used for measuring the drift magnitude and pollution degree of a measuring unit of the front scattering detector, under the calibration mode, the measuring light source 20 is closed, the calibration light source 21 is opened, the laser is uniformly beaten on a measuring area by the calibration light source 21 through the light guide column 23, the signal intensity at the moment is measured and compared with the numerical value after the last calibration, the error calculation is carried out, if the error is larger, the detector drift or the lens pollution is indicated, and a calibration coefficient K2 is obtained and used for compensating the systematic error to improve the accuracy.
The foregoing description is only of the preferred embodiments of the present application and is presented as a description of the principles of the technology being utilized. It will be appreciated by persons skilled in the art that the scope of the invention referred to in this application is not limited to the specific combinations of features described above, but it is intended to cover other embodiments in which any combination of features described above or equivalents thereof is possible without departing from the spirit of the invention. Such as the above-described features and technical features having similar functions (but not limited to) disclosed in the present application are replaced with each other.
Other technical features besides those described in the specification are known to those skilled in the art, and are not described herein in detail to highlight the innovative features of the present invention.
Claims (5)
1. The front scattering detector for measuring the concentration of the high-temperature flue gas particles is characterized by comprising a base, wherein a measuring cavity is arranged in the base, a measuring light path and a calibrating light path are arranged in the base, a sample gas inlet is arranged at the top of the base, and a sample gas outlet is arranged at the bottom of the base;
the measuring light path comprises a measuring light source, a first optical element assembly and a photoelectric receiver, wherein the measuring light source is connected with the base body through a first mounting seat, a first light channel is arranged in the first mounting seat, and the first optical element assembly is arranged in the first light channel;
the calibration light path comprises a calibration light source and a second optical element assembly, the calibration light source is connected with the base body through a second mounting seat, a second optical channel is arranged in the second mounting seat, and the second optical element assembly is arranged in the second optical channel;
the photoelectric receiver is positioned on the optical axis of the calibration light source, the optical axis of the calibration light source intersects with the optical axis of the measurement light source and the axis of the sample gas inlet at one point, and an included angle between the first mounting seat and the second mounting seat is an acute angle.
2. The front scatter detector for measuring particulate matter concentration of high temperature flue gas of claim 1, wherein an optical trap is also mounted in the housing, the optical trap being located on the optical axis of the measuring light source.
3. The front scatter detector for measuring particulate matter concentration in high temperature flue gas of claim 1, wherein the housing has an upper cover at the sample gas inlet and an air curtain assembly around the sample gas inlet, the air curtain assembly being in communication with the measurement cavity;
the middle part of upper cover is equipped with the sample gas passageway that is linked together with the sample gas entry, the lateral part of upper cover is equipped with the sweep gas entry that lets in sweep gas to constitute the sweep gas passageway that sweep gas flows between the inner wall of upper cover and the outer wall of sample gas passageway, sweep gas passageway and gas curtain subassembly switch-on.
4. A front scatter detector for measuring particulate matter concentration in high temperature flue gas according to claim 3, wherein the gas curtain assembly comprises small holes around the sample gas inlet, the small holes being circumferentially arranged around the sample gas inlet, the small holes having a diameter of 1.5-2.1 mm.
5. The front scatter detector for measuring the concentration of high-temperature flue gas particles according to claim 1, wherein a heating unit is installed in the measurement cavity, and the heating unit heats the measurement cavity, so that the temperature in the measurement cavity is kept at 140-155 ℃.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311173539.2A CN117269007A (en) | 2023-09-12 | 2023-09-12 | Forward scattering detector for measuring concentration of particulate matters in high-temperature flue gas |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311173539.2A CN117269007A (en) | 2023-09-12 | 2023-09-12 | Forward scattering detector for measuring concentration of particulate matters in high-temperature flue gas |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117269007A true CN117269007A (en) | 2023-12-22 |
Family
ID=89213501
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311173539.2A Pending CN117269007A (en) | 2023-09-12 | 2023-09-12 | Forward scattering detector for measuring concentration of particulate matters in high-temperature flue gas |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117269007A (en) |
-
2023
- 2023-09-12 CN CN202311173539.2A patent/CN117269007A/en active Pending
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