CN115753673A - TDLAS-based system for measuring concentration of carbon dioxide in flue gas and operation method - Google Patents
TDLAS-based system for measuring concentration of carbon dioxide in flue gas and operation method Download PDFInfo
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- CN115753673A CN115753673A CN202111027000.7A CN202111027000A CN115753673A CN 115753673 A CN115753673 A CN 115753673A CN 202111027000 A CN202111027000 A CN 202111027000A CN 115753673 A CN115753673 A CN 115753673A
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- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 title claims abstract description 160
- 229910002092 carbon dioxide Inorganic materials 0.000 title claims abstract description 80
- 239000001569 carbon dioxide Substances 0.000 title claims abstract description 80
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 49
- 239000003546 flue gas Substances 0.000 title claims abstract description 49
- 238000000041 tunable diode laser absorption spectroscopy Methods 0.000 title claims abstract 10
- 238000000034 method Methods 0.000 title claims description 19
- 238000012545 processing Methods 0.000 claims abstract description 33
- 238000005259 measurement Methods 0.000 claims abstract description 15
- 238000007405 data analysis Methods 0.000 claims abstract description 8
- 238000010521 absorption reaction Methods 0.000 claims description 23
- 238000012544 monitoring process Methods 0.000 claims description 12
- 230000003595 spectral effect Effects 0.000 claims description 12
- 239000004065 semiconductor Substances 0.000 claims description 8
- 238000012360 testing method Methods 0.000 claims description 6
- 238000000862 absorption spectrum Methods 0.000 claims description 5
- 238000001914 filtration Methods 0.000 claims description 4
- 239000007789 gas Substances 0.000 claims description 4
- 239000002028 Biomass Substances 0.000 claims description 3
- 239000003245 coal Substances 0.000 claims 1
- 238000005516 engineering process Methods 0.000 abstract description 7
- 238000001514 detection method Methods 0.000 abstract description 4
- 230000004044 response Effects 0.000 abstract description 3
- 229910052799 carbon Inorganic materials 0.000 description 8
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 7
- 238000000738 capillary electrophoresis-mass spectrometry Methods 0.000 description 2
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- 230000003287 optical effect Effects 0.000 description 2
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- 238000004056 waste incineration Methods 0.000 description 2
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Abstract
The invention discloses a TDLAS-based system for measuring the concentration of carbon dioxide in flue gas, which comprises a laser control measurement module and a data analysis module, wherein the laser measurement module comprises a laser controller, a laser collimator and a photoelectric detector, and the laser controller is used for controlling the temperature and the input current of the laser; the laser is arranged at the downstream of the laser controller and used for emitting laser; the laser collimator is arranged at the downstream of the laser and is used for converting the laser into parallel light; the photoelectric detector is arranged at the downstream of the laser collimator and is used for converting the laser signal into a voltage signal or a current signal; the data analysis module comprises a data acquisition card and a data processing system, and the data acquisition card is used for acquiring voltage signals or current signals; the data processing system is used for processing the data acquired by the acquisition card. The measuring system provided by the invention applies the TDLAS technology to the measurement of the concentration of carbon dioxide in the flue gas of a thermal power plant, and has the advantages of quick response, high precision and low detection limit.
Description
Technical Field
The invention belongs to the technical field of carbon emission monitoring, and particularly relates to a TDLAS-based system for measuring the concentration of carbon dioxide in flue gas and an operation method thereof.
Background
Global climate problems are more and more attracting high attention of people, and low carbon economy characterized by low energy consumption, low emission and low pollution becomes a hotspot of global political economy games. The electricity supply in China mainly takes thermal power as the main part, and the carbon dioxide emission in the electricity industry is determined to be large.
Recently, china continuously carries out new measures and new actions on the aspect of realizing the 30/60 double-carbon target. Formally online carbon emission trading market in 7 months of 2021. The power generation industry is used as the first starting industry of a carbon emission right trading market, and enterprises listed in key emission units exceed 2000 families, so that higher requirements are provided for monitoring carbon dioxide emission of thermal power plants.
The carbon dioxide emission monitoring of coal-fired and gas-fired power plants mainly adopts an emission factor method, and the technology is mature and perfect. However, coal-fired power plants in China generally have a mixed combustion condition, factors such as installed capacity, process technology, actual measurement conditions of carbon content and the like also have great influence on an emission factor method, default values provided by the nation are difficult to be suitable for all power plants, and representativeness of the power plants is always controversial. Currently, on-line monitoring technology (CEMS) is rapidly developing, and most power plants meet the requirements for CEMS provisioning. Therefore, it is necessary to provide an online carbon dioxide emission monitoring method to accurately measure the carbon dioxide emission and assist the healthy development of the carbon emission right trading market.
Disclosure of Invention
The invention aims to provide a TDLAS-based system for measuring the concentration of carbon dioxide in flue gas and an operation method thereof, aiming at the technical problems that the installed capacity, the process technology and the actual measurement condition of carbon content in the prior art have great influence on an emission factor method, and the emission factor method is not suitable for all power plants.
In order to achieve the above object, the present invention provides a system for measuring the concentration of carbon dioxide in flue gas based on TDLAS, comprising: the laser control measuring module is used for processing data measured by the laser control module, the laser measuring module comprises a laser controller, a laser collimator and a photoelectric detector, and the laser controller is used for controlling the temperature and the input current of the laser; the laser is arranged at the downstream of the laser controller and used for emitting laser; the laser collimator is arranged at the downstream of the laser and is used for converting the laser into parallel light; the photoelectric detector is arranged at the downstream of the laser collimator and is used for converting the laser signal into a voltage signal or a current signal; the data analysis module comprises a data acquisition card and a data processing system, and the data acquisition card is used for acquiring voltage signals or current signals; the data processing system is used for processing the data acquired by the acquisition card.
The TDLAS technical method is applied to the measurement of the concentration of the carbon dioxide in the flue gas of the thermal power plant, has the advantages of quick response, high precision and low detection limit, and can be applied to the monitoring of the concentration of the carbon dioxide in the flue gas of various thermal power plants and different compositions; the invention can continuously monitor the carbon dioxide concentration on line and realize the real-time monitoring of the carbon dioxide concentration. The laser collimator of the invention changes the light emitted by the laser into parallel light, so that the beam passing through the smoke reaches the maximum energy density, and the detection sensitivity is improved. The laser controller of the invention realizes the fast tuning and wavelength modulation of the wavelength by changing the input current of the laser; the temperature of the laser is controlled to be within a set temperature range, so that the normal work of the laser is guaranteed.
Further, the parallel light is incident into the flue gas, and carbon dioxide in the flue gas selectively absorbs the parallel light.
Further, the laser is one of a fabry-perot laser, a distributed feedback semiconductor laser, a distributed bragg reflector laser, a vertical cavity surface emitting laser, or an external cavity tuning semiconductor laser.
Furthermore, the photodetector is integrated with a lock-in amplifier, and the lock-in amplifier is used for pre-amplifying and filtering the input signal.
The invention performs pre-amplification and filtering processing on the input signal through the phase-locked amplifier, thereby effectively eliminating other noise signals and improving the measurement precision.
Further, the data processing system calculates the carbon dioxide concentration in the actual flue gas according to the measured carbon dioxide absorption spectral line based on the corresponding relation between the carbon dioxide concentration and the carbon dioxide absorption spectral line which are calibrated in advance.
Furthermore, the flue gas is the gas in the tail flue of the thermal power plant, and the thermal power plant comprises a coal-fired power plant, a gas-fired power plant, an IGCC power plant, a biomass power plant and a waste incineration power plant.
The invention also provides an operation method of the TDLAS-based system for measuring the concentration of the carbon dioxide in the flue gas, which comprises the following steps:
(1) Selecting a proper monitoring point in a tail flue of the power plant, installing a temperature testing instrument, and testing the temperature of the flue gas;
(2) Starting a measuring system, controlling the temperature and the input current of a laser by using a laser controller, emitting laser from the laser, converting the laser into parallel light after passing through a laser collimator, and injecting the parallel light into a flue;
(3) The carbon dioxide in the flue gas selectively absorbs the incident parallel light, and the carbon dioxide has different absorption intensities to the parallel light with different wavelengths and shows the form of a carbon dioxide absorption peak;
(4) Parallel light absorbed by carbon dioxide is incident to a photoelectric detector, and the photoelectric detector converts an optical signal of laser into a voltage signal or a current signal;
(5) The data acquisition card acquires voltage signals or current signals and transmits the voltage signals or the current signals to the data processing system;
(6) The data processing system calculates the integral value of the spectral absorption rate in the full-wave number domain according to the measured carbon dioxide absorption spectral line based on the corresponding relation between the flue gas with the carbon dioxide concentration calibrated in advance and the integral value of the spectral absorption rate in the full-wave number domain at different temperatures, and further calculates the concentration of the carbon dioxide in the actual flue gas at the corresponding temperature;
(7) The data processing system outputs and displays the measured carbon dioxide concentration value.
Compared with the prior art, the invention has the technical effects that: the TDLAS-based system for measuring the concentration of the carbon dioxide in the flue gas, disclosed by the invention, applies a TDLAS technical method to the measurement of the concentration of the carbon dioxide in the flue gas of a thermal power plant, has the advantages of quick response, high precision and low detection limit, and can be suitable for monitoring the concentration of the carbon dioxide in the flue gas of various thermal power plants and different compositions; the invention can continuously monitor the carbon dioxide concentration on line and realize the real-time monitoring of the carbon dioxide concentration. The invention also provides an operation method of the TDLAS-based system for measuring the concentration of the carbon dioxide in the flue gas.
Drawings
The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic diagram of the overall structure of a TDLAS-based system for measuring the concentration of carbon dioxide in flue gas according to the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
The following describes a system for measuring the concentration of carbon dioxide in flue gas based on TDLAS and an operation method thereof according to an embodiment of the present invention with reference to the accompanying drawings.
As shown in fig. 1, the system for measuring the concentration of carbon dioxide in flue gas based on TDLAS comprises: the laser control measurement module is used for processing data measured by the laser control module, the laser measurement module comprises a laser controller, a laser collimator and a photoelectric detector, and the laser controller is used for controlling the temperature and the input current of the laser; the laser is arranged at the downstream of the laser controller and used for emitting laser; the laser collimator is arranged at the downstream of the laser and is used for converting the laser into parallel light; the photoelectric detector is arranged at the downstream of the laser collimator and is used for converting the laser signal into a voltage signal or a current signal; the data analysis module comprises a data acquisition card and a data processing system, and the data acquisition card is used for acquiring voltage signals or current signals; the data processing system is used for processing the data acquired by the acquisition card.
The invention adopts a direct absorption method based on a tunable semiconductor laser absorption spectrum Technology (TDLAS) to determine the carbon dioxide absorption spectrum line, namely, the carbon dioxide laser control measurement module is completed based on the TDLAS technology. The laser measuring module comprises a laser controller, a laser collimator and a photoelectric detector. The laser controller is used for controlling the temperature and the input current of the laser, and the laser controller realizes the rapid tuning and the wavelength modulation of the wavelength by changing the input current of the laser; the temperature of the laser is controlled to be within a set temperature range, so that the normal work of the laser is guaranteed. The laser is arranged at the downstream of the laser controller and used for emitting laser, the laser comprises a Fabry-Perot laser, a distributed feedback semiconductor laser, a distributed Bragg reflection laser, a vertical cavity surface emitting laser and an external cavity tuning semiconductor laser, and the distributed feedback semiconductor laser is adopted in the embodiment, and the central wavelength is 1580nm. The laser collimator is arranged at the downstream of the laser and used for converting laser into parallel light, the parallel light is incident into flue gas, carbon dioxide in the flue gas selectively absorbs the parallel light, and the carbon dioxide has different absorption intensities on the parallel light with different wavelengths and presents the form of a carbon dioxide absorption peak. The parallel light absorbed by the carbon dioxide is incident to the photoelectric detector, the photoelectric detector is arranged at the downstream of the laser collimator and used for converting the laser signal into a voltage signal or a current signal, and the photoelectric detector has a high signal-to-noise ratio to the laser signal within a certain wavelength range, wherein the wavelength range is 500-2000 nm, and the peak value range is 1550-1600 nm. The photoelectric detector is integrated with a phase-locked amplifier which is used for pre-amplifying and filtering an input signal.
The data analysis module comprises a data acquisition card and a data processing system, and the data acquisition card is used for acquiring voltage signals or current signals; the data processing system is used for processing the data acquired by the acquisition card. The data acquisition card transmits the acquired voltage signal or current signal to the data processing system, the data processing system converts the electric signal into a carbon dioxide absorption spectrum, and then the carbon dioxide concentration is calculated through the absorption spectrum. And the data processing system calculates the carbon dioxide concentration in the actual flue gas according to the measured carbon dioxide absorption spectral line based on the corresponding relation between the carbon dioxide concentration and the carbon dioxide absorption spectral line calibrated in advance. The flue gas is the gas in the tail flue of the thermal power plant, and the thermal power plant comprises a coal-fired power plant, a gas-fired power plant, an IGCC power plant, a biomass power plant and a waste incineration power plant.
The invention also provides an operation method of the TDLAS-based system for measuring the concentration of the carbon dioxide in the flue gas, which comprises the following steps:
(1) Selecting a proper monitoring point in a tail flue of the power plant, installing a temperature testing instrument, and testing the temperature of the flue gas;
(2) Starting a measuring system, controlling the temperature and input current of a laser by using a laser controller, emitting laser from the laser, converting the laser into parallel light after passing through a laser collimator, and injecting the parallel light into a flue;
(3) The carbon dioxide in the flue gas selectively absorbs the incident parallel light, and the carbon dioxide has different absorption intensities to the parallel light with different wavelengths and shows the form of a carbon dioxide absorption peak;
(4) Parallel light absorbed by carbon dioxide is incident to a photoelectric detector, and the photoelectric detector converts an optical signal of laser into a voltage signal or a current signal;
(5) The data acquisition card acquires a voltage signal or a current signal and transmits the voltage signal or the current signal to the data processing system;
(6) The data processing system calculates the integral value of the spectral absorption rate in the full-wave number domain according to the measured carbon dioxide absorption spectral line based on the corresponding relation between the flue gas with the carbon dioxide concentration calibrated in advance and the integral value of the spectral absorption rate in the full-wave number domain at different temperatures, and further calculates the concentration of the carbon dioxide in the actual flue gas at the corresponding temperature;
(7) The data processing system outputs and displays the measured carbon dioxide concentration value.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
Claims (7)
1. The TDLAS-based system for measuring the concentration of carbon dioxide in flue gas is characterized by comprising a laser control measurement module and a data analysis module, wherein the data analysis module is used for processing data measured by the laser control module, the laser measurement module comprises a laser controller, a laser collimator and a photoelectric detector, and the laser controller is used for controlling the temperature and the input current of the laser; the laser is arranged at the downstream of the laser controller and is used for emitting laser; the laser collimator is arranged at the downstream of the laser and is used for converting the laser into parallel light; the photoelectric detector is arranged at the downstream of the laser collimator and is used for converting a laser signal into a voltage signal or a current signal; the data analysis module comprises a data acquisition card and a data processing system, and the data acquisition card is used for acquiring the voltage signal or the current signal; and the data processing system is used for processing the data acquired by the acquisition card.
2. The TDLAS-based system of measuring carbon dioxide concentration in flue gas as set forth in claim 1, wherein the collimated light is incident into the flue gas, and the carbon dioxide in the flue gas selectively absorbs the collimated light.
3. The TDLAS-based system for measuring the concentration of carbon dioxide in flue gas as claimed in claim 1 or 2, wherein the laser is one of a fabry-perot laser, a distributed feedback semiconductor laser, a distributed bragg reflector laser, a vertical cavity surface emitting laser or an external cavity tuned semiconductor laser.
4. The TDLAS-based flue gas carbon dioxide concentration measurement system of claim 3, wherein the photodetector is integrated with a lock-in amplifier for pre-amplifying and filtering the input signal.
5. The TDLAS-based flue gas carbon dioxide concentration measuring system of claim 4, wherein the data processing system calculates the carbon dioxide concentration in the actual flue gas from the measured carbon dioxide absorption lines based on pre-calibrated correspondences between carbon dioxide concentrations and carbon dioxide absorption lines.
6. The TDLAS-based system for measuring the concentration of carbon dioxide in flue gas as claimed in claim 2 wherein the flue gas is the gas in the tail flue of a thermal power plant including coal fired power plants, gas fired power plants, IGCC power plants, biomass power plants and refuse burning power plants.
7. The method of operating a TDLAS based flue gas carbon dioxide concentration measurement system of claim 6 including the steps of:
(1) Selecting a proper monitoring point in a tail flue of the power plant, installing a temperature testing instrument, and testing the temperature of the flue gas;
(2) Starting a measuring system, controlling the temperature and input current of a laser by using a laser controller, emitting laser from the laser, converting the laser into parallel light after passing through a laser collimator, and injecting the parallel light into a flue;
(3) The carbon dioxide in the flue gas selectively absorbs the incident parallel light, and the carbon dioxide has different absorption intensities to the parallel light with different wavelengths and shows the form of a carbon dioxide absorption peak;
(4) The parallel light absorbed by the carbon dioxide is incident to a photoelectric detector, and the photoelectric detector converts the light signal of the laser into a voltage signal or a current signal;
(5) The data acquisition card acquires the voltage signal or the current signal and transmits the voltage signal or the current signal to a data processing system;
(6) The data processing system calculates the integral value of the spectral absorption rate in the full-wave number domain according to the measured carbon dioxide absorption spectrum line based on the corresponding relation between the flue gas with the carbon dioxide concentration calibrated in advance and the integral value of the spectral absorption rate in the full-wave number domain at different temperatures, and further calculates the concentration of the carbon dioxide in the actual flue gas at the corresponding temperature;
(7) And the data processing system outputs and displays the measured carbon dioxide concentration value.
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| CN202111027000.7A CN115753673A (en) | 2021-09-02 | 2021-09-02 | TDLAS-based system for measuring concentration of carbon dioxide in flue gas and operation method |
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| CN202111027000.7A CN115753673A (en) | 2021-09-02 | 2021-09-02 | TDLAS-based system for measuring concentration of carbon dioxide in flue gas and operation method |
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