Effect of ambiance on the coal characterization using laser-induced breakdown spectroscopy (LIBS)

Rajavelu, Hemalaxmi; Vasa, Nilesh J.; Seshadri, S.K.

doi:10.1007/s00339-020-03558-7

Cited by 16 publications

(6 citation statements)

References 26 publications

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“…The plasma persistence time corresponding to molecular C 2 (C + C → C 2 , C + CH → C 2 + H) and (C + CN → C 2 + N) band emission at the 516.3 nm wavelength was more prominent than that of CN (C + N → CN) emission at the wavelength of 388.3 nm in the Ar atmosphere. 20 Figure 3 shows the temporal decay characteristics of C 2 molecule emission measured using the PMT from two samples having minimum (30 wt%) and maximum (80 wt%) carbon concentration (Fig. S1, Supplemental Material).…”

Section: Resultsmentioning

confidence: 99%

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Laser-Induced Breakdown Spectroscopy Combined with Temporal Plasma Analysis of C₂ Molecular Emission for Carbon Analysis in Coal

2021

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A benchtop Laser-Induced Breakdown Spectroscopy (LIBS) is demonstrated to determine the elemental carbon content present in raw coal used for combustion in power plants. The spectral intensities of molecular CN and C2 emission are measured together with the atomic carbon (C) and other inorganic elements (Si, Fe, Mg, Al, Ca, Na, and K) in the LIBS spectrum of coal. The emission persistence time of C2 molecule emission is measured from the coal plasma generated by a nanosecond laser ablation with a wavelength of 266 nm in the Ar atmosphere. The emission persistence time of molecular C2 emission along with the spectral intensities of major ash elements (Fe, Si, Al, and Ca) and carbon emissions (atomic C, molecular CN, and C2) shows a better relationship with the carbon wt% of different coal samples. The calibration model to measure elemental carbon (wt%) is developed by combining the spectral characteristics (Spectral intensity) and the temporal characteristics (Emission persistence time of C2 molecule emission). The temporal characteristic studies combined with the spectroscopic data in the PLSR (Partial Least Square Regression) model has resulted in an improvement in the root mean square error of validation (RMSEV), and the relative standard deviation (RSD) is reduced from 10.86% to 4.12% and from 11.32% to 6.04%, respectively.

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Section: Resultsmentioning

confidence: 99%

“…18,19 Also, the spectral emission intensities of inorganic elements (corresponding to the formation of coal ash) from the coal LIBS spectrum were included with the spectral emission intensities of C, CN, and C 2 for the carbon measurement in coal. 20…”

Section: Introductionmentioning

confidence: 99%

Laser-Induced Breakdown Spectroscopy Combined with Temporal Plasma Analysis of C₂ Molecular Emission for Carbon Analysis in Coal

2021

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“…The plasma expansion rate and the background absorption for the laser energy depend on the ionization energy of the plasma surrounded gas. The main air gases are oxygen and nitrogen, which have ionization energies 13.62 and 14.53 eV, respectively, which are relatively smaller compering with 24.58 eV for He gas (Camacho et al 2011;Eseller et al 2012;Kim and Desclaux 2002;Unnikrishnan et al 2010;Welander 1898;Zavilopulo et al 2005) According to that, then in the case of non-purge (air), the background absorbed more laser energy than in the case of purge (He) (Akram et al 2017;Effenberger and Scott 2010;Farooq et al 2014;Rajavelu et al 2020). These results facilitate the opportunity to directly identify the phosphorus concentration in any unknown phosphogypsum sample by determination of T e and N e values for that sample; then the P concentration can be observed directly from linear curves in Fig.…”

Section: Breakdown Spectroscopy Parameters and Calibration-free Studiesmentioning

confidence: 99%

Fast determination of phosphorus concentration in phosphogypsum waste using calibration-free LIBS in air and helium

et al. 2022

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This work represents a novel method to determine phosphorus (P) concentration in phosphogypsum (PG) waste samples using calibration-free laser-induced breakdown spectroscopy (LIBS). A 50 mJ Q-switched Nd: YAG laser has generated the PG LIBS spectrum. Spectroscopic analysis of plasma evolution has been characterized by electron density N e and electron temperature T e using the emission intensity and stark broadening for P I characteristic lines 213.61, 214.91, and 215.40 nm under non-purged (air) and purged (helium) conditions. It was found that both T e and N e have signi cant changes linearly with P concentrations 4195, 5288, 6293, and 6905 ppm. The values of plasma T e and N e increased from about 6900 to 10000 K and 1.1×10 17 to 3.4×10 17 cm − 3 , respectively, for the non-purged PG. On the other hand, T e and N e ranged from 8200 to 11000 K and 1.4×10 17 to 3.5×10 17 cm − 3 , respectively, for the PG purged with helium. It is concluded that T e and N e values represent a ngerprint plasma characterization for a given P concentration in PG samples, which can be used to identify P concentration without a PG's complete analysis. These results demonstrate a new achievement in the eld of spectrochemical analysis of environmental applications.

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“…Along with the NaCl, the Type-4 and Type-5 pollutants consists of 5 wt% of coal and cement respectively, which is maintained common for all the four concentrations. The coal used in the present study has a carbon content of 56.9% [36].…”

Section: Selection Of Pollutants and Coating Detailsmentioning

confidence: 99%

Use of LIBS technique for identification of type of pollutant and ESDD level on epoxy-alumina nanocomposites using ANN

Babu

Neelmani

Vasa

et al. 2021

Meas. Sci. Technol.

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Epoxy-alumina nanocomposites have been coated with different types of pollutants at various concentrations in order to analyze their pollution performance using laser induced breakdown spectroscopy (LIBS) study. Elemental analysis of spectral peaks has been successful in determining the elemental composition of the pollutant present on the surface of the specimens. The conductivity and equivalent salt deposition density (ESDD) values have been determined for all the pollutants at different concentrations. A direct correlation between ESDD and the normalized intensity ratio of LIBS spectral data is noticed. Regression coefficient (R 2 ) has been used as a performance parameter in correlating the ESDD and normalized intensity ratio. Artificial neural network (ANN) technique has been adopted to LIBS spectral data for the classification of the pure epoxy and 3 wt% epoxy-alumina nanocomposite specimen based on conductivity and type of pollutant. ANN developed with conjugate gradient backpropagation with Polak-Ribiere updates training algorithm has reflected higher classification accuracy and required lesser epochs to converge, compared to other training algorithms in classifying the contaminated specimens.

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Effect of ambiance on the coal characterization using laser-induced breakdown spectroscopy (LIBS)

Cited by 16 publications

References 26 publications

Laser-Induced Breakdown Spectroscopy Combined with Temporal Plasma Analysis of C₂ Molecular Emission for Carbon Analysis in Coal

Laser-Induced Breakdown Spectroscopy Combined with Temporal Plasma Analysis of C₂ Molecular Emission for Carbon Analysis in Coal

Fast determination of phosphorus concentration in phosphogypsum waste using calibration-free LIBS in air and helium

Use of LIBS technique for identification of type of pollutant and ESDD level on epoxy-alumina nanocomposites using ANN

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Effect of ambiance on the coal characterization using laser-induced breakdown spectroscopy (LIBS)

Cited by 16 publications

References 26 publications

Laser-Induced Breakdown Spectroscopy Combined with Temporal Plasma Analysis of C2 Molecular Emission for Carbon Analysis in Coal

Laser-Induced Breakdown Spectroscopy Combined with Temporal Plasma Analysis of C2 Molecular Emission for Carbon Analysis in Coal

Fast determination of phosphorus concentration in phosphogypsum waste using calibration-free LIBS in air and helium

Use of LIBS technique for identification of type of pollutant and ESDD level on epoxy-alumina nanocomposites using ANN

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Laser-Induced Breakdown Spectroscopy Combined with Temporal Plasma Analysis of C₂ Molecular Emission for Carbon Analysis in Coal

Laser-Induced Breakdown Spectroscopy Combined with Temporal Plasma Analysis of C₂ Molecular Emission for Carbon Analysis in Coal