Differential absorption spectrum detection system and method

Abstract

The invention discloses a differential absorption spectrum detection system and method, and belongs to the technical field of flue gas detection. The differential absorption spectrum detection system comprises a gas absorption cell and a monochromator; the gas absorption cell and the monochromator are designed in a common optical path; the gas absorption tank is a flue gas channel; the monochromator is used for detecting the flue gas entering the gas absorption tank. Light energy of the light source does not need to be coupled for multiple times and transmitted through optical fibers, and the energy utilization rate is increased; the gas absorption cell and the monochromator share the same light path, and light passes through the monochromator and the gas absorption cell at the same time, so that the structure of the ultraviolet differential spectrum detector is simplified, the weight of the detector is reduced, and the size of the detector is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of smoke detection, and in particular to a differential absorption spectrum detection system and method. Background Art

[0002] With the development of industry, sulfide, nitrogen oxide and other pollutants in flue gas, as important components of industrial pollution sources, not only damage the atmospheric environment and endanger human health, but are also one of the important causes of urban smog, reducing urban visibility, destroying the earth's radiation balance and affecting the global climate. Due to the harm of these harmful emissions to the environment, it is necessary to implement online monitoring of flue gas emissions from fixed pollution sources in order to effectively control and manage them. In recent years, the ultraviolet differential absorption spectroscopy (DOAS) has received more and more attention due to its advantages such as no sampling, easy operation, real-time analysis of multiple components, high sensitivity and low price.

[0003] According to the Lambert-Beer law, the degree of light absorption by the gas to be measured is linearly related to the optical path of the gas and the concentration of the gas. The most common ultraviolet differential spectrometer is to couple the light emitted by the light source into the optical fiber through a condenser; the light is emitted from an optical fiber, and then collimated by a collimator, and then enters a U-shaped gas absorption pool, and then refracted by a dove prism set at the bottom of the U-shaped gas absorption pool and irradiated onto a focusing lens, and then coupled into another optical fiber, and then irradiated onto the slit through this optical fiber, and then enters the spectrometer system; then it passes through a collimator, a grating and a focusing lens machine for optical fiber transmission, and then irradiates onto the detector, thus forming a spectral splitting. The current ultraviolet differential spectrometer generally adopts the structure of light source-optical fiber-gas absorption cell-optical fiber-monochromator, which has a complex structure, large equipment volume and heavy weight. During the transmission process, the light energy needs to undergo two optical fiber coupling and optical fiber transmission, and the energy utilization rate is low, which limits the detection accuracy of the ultraviolet differential spectrometer. Summary of the invention

[0004] In view of the shortcomings of existing ultraviolet differential spectrometers such as complex structure, large size, heavy mass and low energy utilization, the purpose of the present invention is to provide a differential absorption spectrum detection system, which simplifies the structure of the ultraviolet differential spectrometer by removing the optical fiber, adopting direct illumination of the light source, and designing the gas absorption cell and the monochromator to share the same optical path, thereby reducing the number of parts and improving the energy utilization.

[0005] In order to achieve the above technical objectives, the present application provides a differential absorption spectrum detection system, including: a gas absorption cell and a monochromator;

[0006] Gas absorption cell and monochromator co-optical path design;

[0007] The gas absorption pool is a flue gas channel;

[0008] The monochromator is used to detect the flue gas entering the gas absorption cell.

[0009] Preferably, the monochromator is composed of a collimator, a grating, a focusing mirror and a detector, wherein the first light for detecting smoke is transmitted to the detector through the collimator, the grating and the focusing mirror in sequence.

[0010] Preferably, an air inlet is provided at the top of the gas absorption cell for collecting the smoke to be detected;

[0011] An outlet is provided at the lower end of the gas absorption cell for discharging the detected smoke.

[0012] Preferably, one end of the gas absorption cell has an entry slit for guiding the first light to the collimating lens;

[0013] The entry seam is at the end close to the air inlet.

[0014] Preferably, a light source and a condenser are also provided outside the gas absorption cell;

[0015] The condenser is used to focus the second light emitted by the light source to form the first light, and transmit it to the collimator through the entrance slit.

[0016] Preferably, the light source is a deuterium lamp / xenon flash lamp.

[0017] Preferably, the first light forms a first path in the monochromator for guiding light conduction;

[0018] The gas absorption cell has a second path for guiding the flow of flue gas;

[0019] The first path coincides with the second path.

[0020] Preferably, after the first light passes through the collimator, the grating and the focusing lens in sequence, signals of different wavelengths are formed and focused on different positions of the detector to form a spectrum.

[0021] The present invention also discloses a differential absorption spectrum detection method, which is used to perform the method through the above-mentioned system, and the method comprises the following steps:

[0022] The gas to be measured is input into the gas absorption cell and the monochromator through the gas inlet;

[0023] The second light is emitted from the light source, and is focused by a condenser to concentrate the energy at the entrance slit to form the first light;

[0024] The first light passes through the collimator in the absorption cell and then irradiates the grating. After passing through the grating splitter and focusing lens, it is imaged onto the detector. Signals of different wavelengths are focused to different positions of the detector to achieve spectrum splitting.

[0025] Preferably, in the process of forming the second light, a deuterium lamp / xenon flash lamp is used as a light source to form the second light.

[0026] The present invention discloses the following technical effects:

[0027] The present invention simplifies the structure of the ultraviolet differential spectrum detector by placing the gas absorption cell and the monochromator on the same optical path, reduces the application of optical devices, reduces the weight, reduces the size of the instrument, and reduces the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 1 is a schematic diagram of the system structure of the present invention, wherein 1 is a light source; 2 is a condenser; 3 is an entrance slit; 4 is a collimator; 5 is a grating; 6 is a focusing mirror; 7 is a detector; 8 is a gas absorption cell; 9 is an air inlet; and 10 is an air outlet. DETAILED DESCRIPTION

[0030] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0031] like Figure 1 As shown, the present invention provides a differential absorption spectrum detection system, comprising: a gas absorption cell 8 and a monochromator;

[0032] The gas absorption cell 8 and the monochromator share the same optical path design;

[0033] The gas absorption pool 8 is a flue gas channel;

[0034] The monochromator is used to detect the flue gas entering the gas absorption cell 8 .

[0035] Further preferably, the monochromator of the differential absorption spectrum detection system provided by the present invention is composed of a collimator 4, a grating 5, a focusing mirror 6 and a detector 7, wherein the first light for detecting the smoke is transmitted to the detector 7 through the collimator 4, the grating 5 and the focusing mirror 6 in sequence.

[0036] Further preferably, a gas absorption cell 8 of a differential absorption spectrum detection system provided by the present invention is provided with an air inlet 9 at the top thereof for collecting the smoke to be detected;

[0037] A gas outlet 10 is provided at the lower end of the gas absorption cell 8 for discharging the detected smoke.

[0038] Further preferably, one end of the gas absorption cell 8 of the differential absorption spectrum detection system provided by the present invention has an entrance slit 3 for guiding the first light to the collimator 4;

[0039] The inlet slit 3 is at one end close to the air inlet 9 .

[0040] Further preferably, a light source 1 and a condenser 2 are further provided outside the gas absorption cell 8 of the differential absorption spectrum detection system provided by the present invention;

[0041] The condenser 2 is used to focus the second light emitted by the light source 1 to form the first light, and transmit it to the collimator 4 through the entrance slit 3.

[0042] Further preferably, the light source 1 of the differential absorption spectroscopy detection system provided by the present invention is a deuterium lamp / xenon flash lamp.

[0043] Further preferably, the first light of the differential absorption spectrum detection system provided by the present invention forms a first path for guiding light conduction in the monochromator;

[0044] The gas absorption pool 8 has a second path for guiding the flow of flue gas;

[0045] The first path coincides with the second path.

[0046] Further preferably, the first light of the differential absorption spectrum detection system provided by the present invention forms signals of different wavelengths after passing through the collimator 4, the grating 5 and the focusing lens 6 in sequence, and is focused on different positions of the detector 7 to form a spectrum.

[0047] The present invention also discloses a differential absorption spectrum detection method, which is used to perform the method by using the above-mentioned differential absorption spectrum detection system. The method comprises the following steps:

[0048] The gas to be measured is input into the gas absorption cell 8 and the monochromator through the gas inlet 9;

[0049] The second light is emitted from the light source 1, and is focused by the condenser 2, and the energy is concentrated at the entrance slit 3 to form the first light;

[0050] After the first light passes through the collimator 4 in the absorption cell, it is irradiated onto the grating 5, and after being split by the grating 5 and the focusing lens 6, it is imaged onto the detector 7. Signals of different wavelengths are focused on different positions of the detector 7 to achieve spectrum splitting.

[0051] Further preferably, in a differential absorption spectroscopy detection method mentioned in the present invention, in the process of forming the second light, a deuterium lamp / xenon flash lamp is used as the light source 1 to form the second light.

[0052] Embodiment: The present invention establishes a novel differential absorption spectrum detection system. In view of the complex structure of the traditional solution, the present invention uses the gas absorption cell 8 and the monochromator in the same optical path, eliminates the optical fiber, and uses direct light source illumination. Figure 1 As shown, light is emitted from the light source 1, and is focused by the condenser 2 (for gathering energy), and the energy is concentrated at the entrance slit 3. When the light passes through the spectrometer, it also enters the absorption cell 8. After passing through the collimator 44 in the absorption cell 8, the light is irradiated on the grating 5, and after being split by the grating 5 and the focusing lens 6, it is imaged on the detector 77. Signals of different wavelengths are focused on different positions of the detector 7 to achieve spectrum splitting. In the present invention, the gas to be measured enters the gas absorption cell 8 from the air inlet 9, and then is led out of the absorption cell from the air outlet 10.

[0053] The light energy of the light source of the present invention does not need to undergo multiple couplings and optical fiber transmissions, thereby improving energy utilization. Furthermore, the gas absorption cell 8 and the monochromator share the same optical path, so that when the light passes through the monochromator, it also passes through the gas absorption cell 8, thereby simplifying the structure of the ultraviolet differential spectrometer, reducing the weight of the instrument, and reducing the size of the instrument.

[0054] The present invention designs the gas absorption cell 8 and the monochromator to share the same optical path, that is, the light passes through the gas absorption cell 8 while passing through the monochromator, thereby simplifying the system structure; and a deuterium lamp / xenon flash lamp is used as the light source, which is focused and directly irradiated to the monochromator entrance slit 3, thereby improving energy utilization.

[0055] The present invention simplifies the structure of the ultraviolet differential spectrum detector by placing the gas absorption cell 8 and the monochromator in the same optical path, reduces the application of optical devices, reduces the weight, reduces the size of the instrument, and reduces the production cost.

[0056] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0057] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0058] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A differential absorption spectroscopy detection system, characterized in that: include: Gas absorption cell and monochromator; The gas absorption cell and the monochromator share a common optical path design; The gas absorption pool is a flue gas channel; The monochromator is used to detect the flue gas entering the gas absorption cell.

2. A differential absorption spectroscopy detection system according to claim 1, characterized in that: The monochromator is composed of a collimator, a grating, a focusing mirror and a detector, wherein the first light for detecting smoke is transmitted to the detector through the collimator, the grating and the focusing mirror in sequence.

3. A differential absorption spectroscopy detection system according to claim 2, characterized in that: The top of the gas absorption pool is provided with an air inlet for collecting the smoke to be detected; The lower end of the gas absorption cell is provided with a gas outlet for discharging the detected smoke.

4. A differential absorption spectrum detection system according to claim 3, characterized in that: One end of the gas absorption cell has an entry slit for guiding the first light to the collimator; The inlet slit is located at one end close to the air inlet.

5. A differential absorption spectrum detection system according to claim 4, characterized in that: A light source and a condenser are also provided outside the gas absorption cell; The condenser is used to focus the second light emitted by the light source to form the first light, and transmit it to the collimator through the entrance slit.

6. A differential absorption spectrum detection system according to claim 5, characterized in that: The light source is a deuterium lamp / xenon flash lamp.

7. A differential absorption spectrum detection system according to claim 6, characterized in that: The first light forms a first path in the monochromator for guiding light conduction; The gas absorption pool has a second path for guiding the flow of flue gas; The first path coincides with the second path.

8. A differential absorption spectrum detection system according to claim 7, characterized in that: After the first light passes through the collimator, the grating and the focusing lens in sequence, signals of different wavelengths are formed and focused on different positions of the detector to form a spectrum.

9. A differential absorption spectrum detection method, used to perform the method by a differential absorption spectrum detection system according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: Inputting the gas to be measured into the gas absorption cell and the monochromator through the gas inlet; The second light is emitted from the light source, and is focused by a condenser to concentrate the energy at the entrance slit to form the first light; After the first light passes through the collimator in the absorption cell, it is irradiated onto the grating, and after passing through the grating splitter and focusing lens, it is imaged onto the detector. Signals of different wavelengths are focused to different positions of the detector to achieve spectrum splitting.

10. A differential absorption spectrum detection method according to claim 9, characterized in that: In the process of forming the second light, a deuterium lamp / xenon flash lamp is used as the light source to form the second light.

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