Spectral processing method and device for gas raman spectroscopy

Abstract

This invention provides a spectral processing method and apparatus for gas Raman spectroscopy. The method includes: acquiring a basic background spectrum; performing Raman spectroscopy on a sample gas to obtain a raw sample gas spectrum; correcting the basic background spectrum to obtain a background sample gas spectrum; obtaining an initial sample gas spectrum based on the raw sample gas spectrum and the background sample gas spectrum; performing baseline correction on the initial sample gas spectrum to obtain a corrected sample gas spectrum; and normalizing the corrected sample gas spectrum to obtain a spectrally processed Raman spectrum. The method provided by this invention overcomes the influence of changes in detection conditions, significantly improves the accuracy of Raman spectroscopy, enhances the characteristic characteristics of Raman peaks of each component in a mixed gas sample, and lays a solid foundation for subsequent quantitative analysis of the mixed gas composition.

Description

Technical Field

[0001] This invention relates to the field of chemometrics, specifically to a spectral processing method and a spectral processing apparatus for gas Raman spectra. Background Technology

[0002] Laser Raman spectroscopy is a molecular structure characterization technique based on the Raman scattering effect. It can achieve non-destructive and rapid analysis of samples. Moreover, the spectral analysis system has a simple structure, low maintenance cost, and is easy to operate, and has been widely used in oil refining, chemical industry, pharmaceutical industry and other fields.

[0003] To enhance Raman signal intensity, researchers both domestically and internationally have proposed various methods, such as multiple reflections of the excitation light, increasing laser power, artificially pressurizing the sample gas, and increasing the collection angle of the Raman scattered light. However, the actual Raman spectrum obtained is not only related to the composition of the gas mixture but also closely related to many external interference factors (such as sample gas pressure and laser power). It is difficult to ensure that these parameters remain constant during online applications. Furthermore, the metal materials in the sampling cell also generate corresponding Raman spectra under the influence of the laser, which are also known as "background spectra." Eliminating the influence of these interference factors on the spectrum is crucial, as it directly affects the repeatability and accuracy of subsequent online analyzers. Summary of the Invention

[0004] To address the technical problem that interference factors cannot be eliminated in existing technologies, thus affecting the accuracy of Raman spectroscopy detection, this invention provides a spectral processing method and a spectral processing device for gas Raman spectra. This method can eliminate the influence of measurement condition fluctuations on gas Raman spectra and improve the accuracy of Raman spectroscopy detection.

[0005] To achieve the above objectives, the first aspect of the present invention provides a spectral processing method for gas Raman spectra, comprising the following steps: obtaining a basic background spectrum; performing Raman spectral detection on a sample gas to obtain a raw sample gas spectrum; correcting the basic background spectrum to obtain a sample gas background spectrum; obtaining an initial sample gas spectrum based on the raw sample gas spectrum and the sample gas background spectrum; performing baseline correction on the initial sample gas spectrum to obtain a corrected sample gas spectrum; and normalizing the corrected sample gas spectrum to obtain a spectrally processed sample gas Raman spectrum.

[0006] Furthermore, obtaining the basic background spectrum includes: performing Raman spectroscopy detection on the background gas to obtain an original spectrum, wherein the background gas includes air or nitrogen; and removing the Raman peaks in the original spectrum that correspond to the background gas to obtain the basic background spectrum.

[0007] Further, the step of correcting the basic background spectrum to obtain the sample gas background spectrum includes: determining the predicted components of the sample gas; selecting multiple reference spectral regions in the basic background spectrum according to the predicted components, wherein the reference spectral regions do not include the Raman peaks of the predicted components; and performing sample gas regression processing on the light intensity of the basic background spectrum in the reference spectral regions and the light intensity of the original sample gas spectrum in the reference spectral regions to obtain the sample gas background spectrum.

[0008] Furthermore, the reference spectral region does not include the Raman peak of the predicted component, and the intensity variation between any two reference spectral regions is greater than a set value.

[0009] Furthermore, the degree of light intensity variation between any two reference spectral regions is obtained in the following manner:

[0010]

[0011] Where C represents the light intensity variation, and L1 and L2 are the average light intensity values ​​of the two reference spectral regions, respectively.

[0012] Further, the baseline correction of the initial spectrum of the sample gas to obtain the corrected spectrum of the sample gas includes: acquiring a spectral baseline; removing the spectral baseline from the initial spectrum of the sample gas to obtain the corrected spectrum of the sample gas.

[0013] Further, obtaining the spectral baseline includes: dividing the initial spectrum of the sample gas into multiple segments according to the spectral shape of the initial spectrum of the sample gas; using a fitting algorithm corresponding to the spectral shape of each segment of the initial spectrum of the sample gas to fit the baseline of each segment of the initial spectrum of the sample gas; and obtaining the spectral baseline based on the baseline of each segment of the initial spectrum of the sample gas.

[0014] Furthermore, the fitting algorithm includes an iterative filtering algorithm or a polynomial iterative algorithm.

[0015] Further, the normalization processing of the sample gas calibration spectrum includes: determining the common components of the sample gas and the detection gas, wherein the detection gas and the sample gas are gases continuously collected during the production process; determining the characteristic peak heights of the common components in the sample gas calibration spectrum; and determining the sample gas Raman spectrum based on the sample gas calibration spectrum and the characteristic peak heights.

[0016]

[0017] Where N(v) is the sample gas Raman spectrum, S(v) is the sample gas corrected spectrum, and P i The characteristic peak height.

[0018] A second aspect of the present invention provides a spectral processing apparatus for gas Raman spectroscopy, the apparatus comprising: an acquisition unit for acquiring a basic background spectrum; and performing Raman spectral detection on a sample gas to obtain an original sample gas spectrum; a correction unit for correcting the basic background spectrum to obtain a sample gas background spectrum; a background removal unit for obtaining an initial sample gas spectrum based on the original sample gas spectrum and the sample gas background spectrum; a calibration unit for performing baseline calibration on the initial sample gas spectrum to obtain a calibrated sample gas spectrum; and a normalization processing unit for normalizing the calibrated sample gas spectrum to obtain a spectrally processed sample gas Raman spectrum.

[0019] The present invention has at least the following technical effects through the technical solution provided by the present invention:

[0020] The spectral processing method for gas Raman spectroscopy of the present invention first obtains a basic background spectrum, then corrects the basic background spectrum to obtain a sample gas background spectrum, then performs Raman spectroscopy detection on the sample gas to obtain the original sample gas spectrum, subtracts the sample gas background spectrum from the original sample gas spectrum to obtain the initial sample gas spectrum, and performs baseline correction on the initial sample gas spectrum to obtain the corrected sample gas spectrum, and then normalizes the corrected sample gas spectrum to obtain the spectrally processed sample gas Raman spectrum. The method provided by the present invention can overcome the influence of changes in detection conditions, significantly improve the accuracy of Raman spectroscopy, improve the characteristicity of Raman peaks of each component in the mixed gas sample, and lay a good foundation for subsequent quantitative analysis of the mixed gas composition.

[0021] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0022] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0023] Figure 1 A flowchart of a spectral processing method for gas Raman spectroscopy provided in an embodiment of the present invention;

[0024] Figure 2 A schematic diagram of the gas Raman spectroscopy testing platform used in the spectral processing method for gas Raman spectroscopy provided in the embodiments of the present invention;

[0025] Figure 3 This is a schematic diagram of the background spectrum and N2 spectrum in the spectral processing method for gas Raman spectroscopy provided in an embodiment of the present invention;

[0026] Figure 4This is a schematic diagram of the original sample gas spectrum and the basic background spectrum in the spectral processing method for gas Raman spectroscopy provided in an embodiment of the present invention.

[0027] Figure 5 This is a magnified schematic diagram of a localized reference spectral region in the spectral processing method for gas Raman spectroscopy provided in an embodiment of the present invention.

[0028] Figure 6 A schematic diagram illustrating the correspondence between the light intensity of the original sample gas spectrum in the reference spectral region and the light intensity of the basic background spectrum in the reference spectral region in the spectral processing method for gas Raman spectroscopy provided in this embodiment of the invention.

[0029] Figure 7 This is a schematic diagram of the sample gas background spectrum in the spectral processing method for gas Raman spectroscopy provided in an embodiment of the present invention;

[0030] Figure 8 This is a schematic diagram of the initial spectrum of the sample gas in the spectral processing method for gas Raman spectroscopy provided in an embodiment of the present invention;

[0031] Figure 9 This is a schematic diagram showing a partial magnification of the initial spectrum of the sample gas in the spectral processing method for gas Raman spectroscopy provided in an embodiment of the present invention.

[0032] Figure 10 A schematic diagram of the spectral baseline in the spectral processing method for gas Raman spectroscopy provided in an embodiment of the present invention;

[0033] Figure 11 This is a schematic diagram of the sample gas correction spectrum in the spectral processing method for gas Raman spectroscopy provided in an embodiment of the present invention;

[0034] Figure 12 This is a schematic diagram of the sample gas Raman spectrum in the spectral processing method for gas Raman spectroscopy provided in an embodiment of the present invention;

[0035] Figure 13 This is a schematic diagram showing a partial magnification of the sample gas Raman spectrum in the spectral processing method for gas Raman spectroscopy provided in an embodiment of the present invention;

[0036] Figure 14 A schematic diagram of a gas Raman spectroscopy processing device provided in an embodiment of the present invention. Detailed Implementation

[0037] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0038] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0039] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used to describe the relative positions of components in relation to the directions shown in the accompanying drawings or in relation to the vertical, perpendicular, or gravitational directions.

[0040] Ethylene cracking furnaces are crucial for producing essential organic chemical raw materials such as ethylene, propylene, and butadiene. Material analysis of ethylene cracking furnaces is therefore extremely important. The outlet gaseous material (cracking gas) contains light components such as H2, CH4, C2H6, C2H4, C3H8, and C3H6. Determining the content of these components in the cracking gas can reveal the cracking depth and the distribution of cracking products, helping to guide the optimization of process parameters. Current techniques typically employ Raman spectroscopy to analyze the composition of the cracking gas. Pure Ar or other inert gases are passed into a sealed sampling tube. Since inert gases have no Raman response, the detected spectrum is the background spectrum. For the sample gas to be tested, its original spectrum is first obtained, and then the background spectrum is subtracted to obtain its effective Raman spectrum. However, the background spectrum is not constant. Experiments show that the background spectrum is related to factors such as laser power, sample gas pressure, and temperature. In continuous online applications, the above method has significant limitations.

[0041] Furthermore, gas Raman spectroscopy commonly exhibits baseline drift, the magnitude of which is related to numerous external interference factors (such as laser power, integration time, sample gas pressure, and temperature), and the amplitude of the baseline drift varies across the entire spectral range. These external interferences directly affect the height and peak area of ​​the Raman characteristic peaks of each component. To improve the repeatability of subsequent quantitative Raman analysis, the raw Raman spectrum needs to be preprocessed so that the preprocessed spectrum is largely unaffected by measurement conditions and depends only on the composition of the gas mixture.

[0042] To address the aforementioned problems, the spectral processing method for gas Raman spectra proposed in this invention mainly includes: dynamic correction and subtraction of the background spectrum, and baseline correction and normalization of the Raman spectrum. The method provided by this invention can essentially eliminate the influence of measurement condition fluctuations on gas Raman spectra, significantly improving the accuracy of Raman spectroscopy.

[0043] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0044] Please refer to Figure 1 This invention provides a spectral processing method for gas Raman spectra, which includes the following steps: S101: Obtaining a basic background spectrum;

[0045] Furthermore, obtaining the basic background spectrum includes: performing Raman spectroscopy detection on the background gas to obtain an original spectrum, wherein the background gas includes air or nitrogen; and removing the Raman peaks in the original spectrum that correspond to the background gas to obtain the basic background spectrum.

[0046] Specifically, in this embodiment of the invention, air or pure N2 is introduced into the sampling tube, its original spectrum is detected, and the air or N2 Raman peaks in the original spectrum are subtracted to obtain the basic background spectrum B. 0(v) .

[0047] The method provided by this invention allows for the detection of readily available air or N2. By subtracting the Raman peaks of air or pure N2 from the original spectrum, a basic background spectrum can be obtained, thus improving the convenience of obtaining the basic background spectrum.

[0048] S102: Perform Raman spectroscopy on the sample gas to obtain the original spectrum of the sample gas;

[0049] S103: Correct the basic background spectrum to obtain the sample gas background spectrum;

[0050] Further, the step of correcting the basic background spectrum to obtain the sample gas background spectrum includes: determining the predicted components of the sample gas; selecting multiple reference spectral regions in the basic background spectrum according to the predicted components, wherein the reference spectral regions do not include the Raman peaks of the predicted components; and performing sample gas regression processing on the light intensity of the basic background spectrum in the reference spectral regions and the light intensity of the original sample gas spectrum in the reference spectral regions to obtain the sample gas background spectrum.

[0051] Furthermore, the reference spectral region does not include the Raman peak of the predicted component, and the intensity variation between any two reference spectral regions is greater than a set value.

[0052] Furthermore, the degree of light intensity variation between any two reference spectral regions is obtained in the following manner:

[0053]

[0054] Where C represents the light intensity variation, and L1 and L2 are the average light intensity values ​​of the two reference spectral regions, respectively.

[0055] Specifically, in this embodiment of the invention, the predicted components of the sample gas are first predicted. To ensure the reliability of the correction of the basic background spectrum B0(v), multiple reference spectral regions are selected in the basic background spectrum B0(v). The reference spectral regions do not include the Raman peaks of the predicted components, and the intensity variation between any two reference spectral regions is relatively large (greater than a set value). Using the intensity of the basic background spectrum B0(v) in the reference spectral regions as the input vector and the intensity of the original sample gas spectrum I(v) in the reference spectral regions as the output vector, the gain K and intercept b are obtained through linear regression, thus obtaining the sample gas background spectrum B(v) = KB0(v) + b.

[0056] S104: Obtain the initial spectrum of the sample gas based on the original spectrum of the sample gas and the background spectrum of the sample gas;

[0057] Specifically, in this embodiment of the invention, the initial spectrum A(v) of the sample gas can be obtained by subtracting the background spectrum B(v) of the sample gas from the original spectrum I(v), that is, A(v) = I(v) – B(v).

[0058] S105: Perform baseline correction on the initial spectrum of the sample gas to obtain the corrected spectrum of the sample gas;

[0059] Further, the baseline correction of the initial spectrum of the sample gas to obtain the corrected spectrum of the sample gas includes: acquiring a spectral baseline; removing the spectral baseline from the initial spectrum of the sample gas to obtain the corrected spectrum of the sample gas.

[0060] Further, obtaining the spectral baseline includes: dividing the initial spectrum of the sample gas into multiple segments according to the spectral shape of the initial spectrum of the sample gas; using a fitting algorithm corresponding to the spectral shape of each segment of the initial spectrum of the sample gas to fit the baseline of each segment of the initial spectrum of the sample gas; and obtaining the spectral baseline based on the baseline of each segment of the initial spectrum of the sample gas.

[0061] Furthermore, the fitting algorithm includes an iterative filtering algorithm or a polynomial iterative algorithm.

[0062] Specifically, in this embodiment of the invention, the spectral shape of the initial spectrum A(v) of the sample gas is obtained. Based on the spectral shape of the initial spectrum A(v), it is divided into multiple segments: segments with narrower peak half-widths (HWHMs) and segments with wider HWHMs. The segments with narrower HWHMs are fitted with a baseline using an iterative filtering algorithm, while the segments with wider HWHMs are fitted with a baseline using a polynomial iterative algorithm. The two baseline segments are then merged to obtain the spectral baseline BL(v). The spectral baseline BL(v) is subtracted from the initial spectrum A(v) to obtain the corrected spectrum S(v), i.e., S(v) = A(v) – BL(v).

[0063] S106: Normalize the sample gas calibration spectrum to obtain the sample gas Raman spectrum after spectral processing.

[0064] Further, the normalization processing of the sample gas calibration spectrum includes: determining the common components of the sample gas and the detection gas, wherein the detection gas and the sample gas are gases continuously collected during the production process; determining the characteristic peak heights of the common components in the sample gas calibration spectrum; and determining the sample gas Raman spectrum based on the sample gas calibration spectrum and the characteristic peak heights.

[0065]

[0066] Where N(v) is the sample gas Raman spectrum, S(v) is the sample gas corrected spectrum, and P i The characteristic peak height.

[0067] Specifically, in this embodiment of the invention, the common components contained in multiple samples (sample gas and detection gas) continuously collected during the production process are determined. The peak heights of the characteristic peaks of the common components in the sample gas calibration spectra of the multiple samples are determined. The common component with the highest peak height is selected, such as the component with the highest peak height or the component with the second highest peak height. The peak height of this common component in the sample gas calibration spectrum S(v) is determined as the characteristic peak height P. i Let N(v) = S(v) / P i The final Raman spectrum N(v) of the sample gas was obtained.

[0068] The spectral processing method for gas Raman spectroscopy provided by this invention can overcome the influence of changes in detection conditions, significantly improve the accuracy of Raman spectroscopy, enhance the characteristicity of Raman peaks of each component in the mixed gas sample, and lay a good foundation for subsequent quantitative analysis of the mixed gas composition.

[0069] The method provided by this invention is applicable not only to Raman spectroscopy processing of pyrolysis gases, but also to Raman spectroscopy processing of other gases.

[0070] Example 1

[0071] Please refer to Figure 2 , Figure 2 This is the gas Raman spectroscopy testing platform used in this invention. The main optical components are: a laser, optical fibers (excitation and collection fibers), a Raman probe, and a fiber optic spectrometer. The laser is a 532nm center wavelength laser; the Raman probe is a 532nm fiber optic probe; and the fiber optic spectrometer is a TEC-cooled fiber optic spectrometer.

[0072] The measurement process of this system is as follows: the sample gas is intermittently or continuously introduced into the sampling tube; the laser emits a monochromatic laser, which is transmitted to the Raman probe through the excitation fiber. After being focused by the Raman probe, the sample is illuminated, and the Raman scattered light generated is collected by the Raman probe and then transmitted back to the fiber optic spectrometer through the collection fiber; the Raman scattered light is spectrally dispersed by the grating of the fiber optic spectrometer, photoelectrically detected, and converted into a digital spectral signal by analog-to-digital conversion. The signal is then transmitted by the fiber optic spectrometer to a PC for analysis by Raman spectroscopy analysis software.

[0073] The background spectrum is mainly caused by laser excitation within the stainless steel cavity of the Raman detection cell and is independent of the sample gas composition. Since inert gases such as Ar have no Raman signal, they can be introduced into the sampling tube beforehand, and the original spectrum can be detected using the aforementioned gas Raman spectroscopy testing platform. Linear interpolation over the entire Raman shift range yields the basic background spectrum. Alternatively, air or N2 gas can be introduced into the sampling tube, and the original spectrum can be detected using the same gas Raman spectroscopy testing platform. Since the Raman peaks for N2 and O2 are single peaks, located at 2331 and 1556 cm⁻¹ respectively... -1 This allows us to subtract these two peaks from the original spectrum. The original spectrum of N2 is as follows: Figure 3 As shown by the solid line, it still contains a small amount of residual O2 gas from the sampling tube. The basic background spectrum B0(v) obtained after subtracting the N2 and O2 peaks is as follows: Figure 3 As shown by the dashed line.

[0074] Raman spectroscopy was performed on the sample gas of ethylene cracking gas to obtain the original spectrum I(v) of the sample gas;

[0075] The original spectrum I(v) and the basic background spectrum B0(v) of the sample gas are as follows: Figure 4 As shown. Based on the predicted component peaks that the cracked gas may contain, multiple reference spectral regions are selected in the basic background spectrum B0(v). These reference regions do not include the Raman peaks of the predicted components, and the intensity variation between any two reference spectral regions is significant. Please refer to [reference needed]. Figure 5 , Figure 5 The middle reference spectral region is [440–490, 650–700] cm. -1 The region. For this cracked gas spectrum, due to the influence of measurement conditions, its stray spectrum is not completely consistent with the basic background spectrum B0(v), but the spectral type is consistent.

[0076] For a specific ethylene cracking experiment, 80 Raman spectra of the cracked gas were continuously collected (sampling period of 70 s). The following section uses the 50th sample gas's original spectrum I(v) as an example to explain the specific processing procedure. The main components of this sample gas are: 10.09% H2, 22.65% CH4, 3.62% C2H6, 43.46% C2H4, 0.35% C3H8, and 11.54% C3H6.

[0077] Please refer to Figure 6 Using the intensity of the basic background spectrum B0(v) in the reference spectral region as the input vector and the intensity of the original sample gas spectrum I(v) in the reference spectral region as the output vector, the gain K and intercept b obtained by linear regression are 0.9152 and 91.5565, respectively. Figure 7 The sample gas background spectrum shown is B(v) = KB0(v) + b.

[0078] Please refer to Figure 8 and Figure 9 The initial spectrum of the sample gas, A(v), can be obtained by subtracting the background spectrum B(v) from the original spectrum I(v) of the sample gas, i.e., A(v) = I(v) – B(v).

[0079] By subtracting the background spectrum of the sample gas contained in the original sample gas spectrum, the spectral shape is significantly improved, although there is a certain drift at the bottom of the spectrum (also known as "baseline drift"). Therefore, segmented baseline correction is used for the initial spectrum of the sample gas.

[0080] Based on the spectral shape of the initial gas sample spectrum A(v), the initial gas sample spectrum A(v) is divided into 300–2200 cm⁻¹ and 2201–3100 cm⁻¹. -1 Multiple segments. For the first spectral segment, the half-width of the filter window is 200cm. -1 The baseline was fitted using an iterative SG filtering algorithm; for the second spectral band, a polynomial iterative algorithm with a polynomial order of 1 was used for baseline fitting. The final fitted spectral baseline BL(v) is shown below. Figure 10 As shown by the dashed line, the baseline-corrected sample gas spectrum is S(v) = A(v) – BL(v), as... Figure 11 As shown.

[0081] The common components contained in multiple samples continuously collected during the production process are determined, and the peak heights of the characteristic peaks of the common components in the sample gas calibration spectra of the multiple samples are determined. The common component with the higher peak height is selected; in this embodiment, H2 is selected. In the sample gas calibration spectrum S(v), the peak height of the Raman peak of H2 is taken as the characteristic peak height P. i Let N(v) = S(v) / P i The final processed sample gas Raman spectrum N(v) is obtained, as follows: Figure 12 As shown.

[0082] Figure 12 The middle is located at 1345cm -1 The characteristic peak height of ethylene is 4.1944. A local magnification of the gas Raman spectrum of this sample is shown below. Figure 13 As shown, it is located between 2200 and 2250 cm. -1The signal-free region has a spectral standard deviation of 0.0022, reflecting the average noise level. For the ethylene Raman peak, the signal-to-noise ratio is 4.1944 / (3*0.0022) = 700:1; for the H2 peak, the signal-to-noise ratio is 1.0 / (3*0.0022) = 150:1. Therefore, for olefinic components such as H2 and C2H4, which exhibit strong pure Raman signals, the theoretical detection limit is close to 0.07%.

[0083] Please refer to Figure 14 A second aspect of the present invention provides a spectral processing apparatus for gas Raman spectroscopy, the apparatus comprising: an acquisition unit for acquiring a basic background spectrum; and performing Raman spectral detection on a sample gas to obtain an original sample gas spectrum; a correction unit for correcting the basic background spectrum to obtain a sample gas background spectrum; a background removal unit for obtaining an initial sample gas spectrum based on the original sample gas spectrum and the sample gas background spectrum; a calibration unit for performing baseline calibration on the initial sample gas spectrum to obtain a calibrated sample gas spectrum; and a normalization processing unit for normalizing the calibrated sample gas spectrum to obtain a spectrally processed sample gas Raman spectrum.

[0084] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0085] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0086] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A spectral processing method for gas Raman spectra, characterized in that, The method includes: Obtain the basic background spectrum; Raman spectroscopy was performed on the sample gas to obtain the original spectrum of the sample gas; The basic background spectrum is corrected to obtain the sample gas background spectrum; The initial spectrum of the sample gas is obtained based on the original spectrum of the sample gas and the background spectrum of the sample gas. The process of baseline correction of the initial spectrum of the sample gas to obtain the corrected spectrum includes: acquiring a spectral baseline; removing the spectral baseline from the initial spectrum of the sample gas to obtain the corrected spectrum; acquiring the spectral baseline includes: dividing the initial spectrum of the sample gas into narrow peak segments and wide peak segments based on the peak half-width; wherein the peak half-width of the narrow peak segment is smaller than that of the wide peak segment; fitting the baseline of the narrow peak segment using an iterative filtering algorithm, and fitting the baseline of the wide peak segment using a polynomial iterative algorithm; merging the fitted baselines of the narrow peak segment and the wide peak segment to obtain the spectral baseline; The sample gas calibration spectrum is normalized to obtain the sample gas Raman spectrum after spectral processing.

2. The method according to claim 1, characterized in that, The acquisition of the basic background spectrum includes: Raman spectroscopy is performed on the background gas to obtain the original spectrum, wherein the background gas includes air or nitrogen. Remove the Raman peaks corresponding to the background gas from the original spectrum to obtain the basic background spectrum.

3. The method according to claim 2, characterized in that, The step of correcting the basic background spectrum to obtain the sample gas background spectrum includes: Determine the predicted components of the sample gas; Based on the predicted components, multiple reference spectral regions are selected in the basic background spectrum, wherein the reference spectral regions do not include the Raman peaks of the predicted components; The sample gas background spectrum is obtained by performing sample gas regression processing on the light intensity of the basic background spectrum in the reference spectral region and the light intensity of the original sample gas spectrum in the reference spectral region.

4. The method according to claim 3, characterized in that, The reference spectral region does not include the Raman peak of the predicted component, and the intensity variation between any two reference spectral regions is greater than a set value.

5. The method according to claim 4, characterized in that, The intensity variation between any two reference spectral regions is obtained in the following way: ； Where C represents the light intensity variation, and L1 and L2 are the average light intensity values ​​of the two reference spectral regions, respectively.

6. The method according to claim 1, characterized in that, The normalization process for the sample gas calibration spectrum includes: Identify the common components of the sample gas and the detection gas, wherein the detection gas and the sample gas are gases continuously collected during the production process; Determine the characteristic peak heights of the common components in the sample gas calibration spectrum; The sample gas Raman spectrum is determined based on the sample gas corrected spectrum and the characteristic peak height: ； in, N ( v ( ) represents the Raman spectrum of the sample gas. S ( v (This is the sample gas calibration spectrum.) P i The characteristic peak height.

7. A spectral processing device for gas Raman spectroscopy, characterized in that, The spectral processing device for the gas Raman spectrum includes: The acquisition unit is used to acquire the basic background spectrum and to perform Raman spectroscopy on the sample gas to obtain the original spectrum of the sample gas. The correction unit is used to correct the basic background spectrum to obtain the sample gas background spectrum; The background removal unit is used to obtain the initial spectrum of the sample gas based on the original spectrum of the sample gas and the background spectrum of the sample gas. A correction unit is used to perform baseline correction on the initial spectrum of the sample gas to obtain a corrected spectrum; the correction unit includes: acquiring a spectral baseline; removing the spectral baseline from the initial spectrum of the sample gas to obtain the corrected spectrum; acquiring the spectral baseline includes: dividing the initial spectrum of the sample gas into a narrow peak segment and a wide peak segment according to the peak half-width; wherein the peak half-width of the narrow peak segment is smaller than that of the wide peak segment; fitting the baseline of the narrow peak segment using an iterative filtering algorithm, and fitting the baseline of the wide peak segment using a polynomial iterative algorithm; merging the fitted baselines of the narrow peak segment and the wide peak segment to obtain the spectral baseline; The normalization processing unit is used to normalize the sample gas correction spectrum to obtain the sample gas Raman spectrum after spectral processing.

Images