Elemental analysis of coal by means of the Laser Induced Breakdown Spectroscopy (LIBS) technique

Musazzi, S.; Golinelli, E.; Perini, U.; Barberis, F.; Zanetta, G. A.

doi:10.1109/sas.2012.6166301

Cited by 21 publications

(18 citation statements)

References 3 publications

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“…The ionic transitions are occurring more likely in the hot plasma core and rapidly vanish in the expanding plasma. This is consistent with the time integrated image of a ns laser plasma on the brass sample at atmospheric pressure which clearly distinguishes the hotter plasma core by the cooler plasma exterior [23]. Laser induced plasmas decay very fast with time and distance from the target.…”

Section: Emission Spectra Of Thalliumsupporting

confidence: 86%

Spectroscopic investigations of the laser induced thallium plasma

et al. 2018

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Laser-induced breakdown spectroscopy has been used for the spectroscopic characterization of thallium (Tl) plasma, produced using the fundamental harmonic of a Q-switched Nd:YAG laser. The optical emission was recorded in the spectral range of 200-720 nm using a set of five miniature spectrometers with 2.5 μs delay time and 2.1 ms gate width. The plasma temperature was determined using the Boltzmann-plot method, and the electron number density was deduced from the Stark broadened line profile of Tl (I) 322.97 nm line. The plasma temperature and electron number density have been evaluated as a function of laser irradiance (5.2 × 10 10 to 8.2 × 10 10 W cm −2 ) which increases from 11 450-13 780 K and (5.2-6.2) × 10 17 cm −3 respectively. The spatial profile of these parameters shows a decreasing trend from 13 000-7600 K and (6.3-5.8) × 10 17 cm −3 along the plume expansion length up to 2.5 mm from the target surface. The spatial behavior of the plasma parameters has been discussed in relation to the reported temporal trend to indicate inter-relation of the spatiotemporal profile of the laser induced plasma.

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Section: Emission Spectra Of Thalliumsupporting

confidence: 86%

Spectroscopic investigations of the laser induced thallium plasma

et al. 2018

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“…LIBS is a technique for in situ species measurement of gas, liquids and solids . For coal/biomass combustion, LIBS is commonly used for coal sample analysis, for ash analysis, and to measure sodium or potassium release. − A benefit of the LIBS process is that species are broken into their elemental components by laser plasma, meaning that the signal arises from all respective conformations of a species in the measurement region. In addition, because the characteristic time scale of LIBS measurement is small, it can be used to monitor the time-resolved release of Na above a burning coal particle, which is not influenced by scattering, allowing proper measurement during all phases of coal combustion.…”

Section: Introductionmentioning

confidence: 99%

Effects of Microwave Irradiation on Combustion and Sodium Release Characteristics of Zhundong Lignite

Wang

Liu

et al. 2016

Energy Fuels

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Lignite can be upgraded by using microwave irradiation (MI), which may change physical and chemical properties of the coal, affecting its combustion characteristics. In this work, MI was used to upgrade coal samples, and the changes in combustion characteristics of the upgraded coal samples were analyzed by thermogravimetric analysis (TGA) and surface temperature measurement. The method of sequential extraction was employed to investigate the changes of various Na classes in different coal samples, and laser-induced breakdown spectroscopy was then used to measure the temporal sodium release during combustion of the different coal samples. Results show that the MI process significantly reduces the moisture concentration, thereby increasing the carbon content and calorific value of the coal. The decrease of the oxygen–carbon atomic ratio indicates an improvement of the coal rank. The TGA shows that the upgrading process will delay the combustion process toward higher temperatures. The comprehensive combustion parameter calculated from the TGA shows the combustion performance of upgraded coal samples became worse, which is also seconded by the measured surface temperatures. MI produces interconversion among different sodium classes, particularly between NH4Ac-soluble sodium and water-soluble sodium. The sodium release characteristics are similar to the surface temperature profiles, indicating that, despite the MI process, sodium release is predominantly controlled by the combustion process. However, the MI process is found to increase both the mass fraction of sodium in coal samples and the amount of sodium release during the combustion process.

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“…of coal and ash samples are investigated by many research groups. [7][8][9][10][11][12][13][14] Furthermore, the following consideration of the extremely complex of the composition and physicochemical property of various types of coal, the theoretical linear relationship between the emission line intensity and elemental concentration can be weakened for proximate analysis 5 . The measurement precision and accuracy will suffer from experimental parameter fluctuations and matrix effects.…”

Section: Introductionmentioning

confidence: 99%

Development of a Rapid Coal Analyzer Using Laser-Induced Breakdown Spectroscopy (LIBS)

Yao

Zhao

et al. 2018

Appl Spectrosc

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Determination of coal quality plays a major role in coal-fired power plants and coal producers for optimizing the utilization efficiency and controlling the quality. In this work, a rapid coal analyzer based on laser-induced breakdown spectroscopy (LIBS) was developed for rapid quality analysis of pulverized coal. The structure of the LIBS apparatus was introduced in detail. To avoid time-consuming and complicated sample preparation, a pulverized feeding machine was designed to form a continuously stable coal particle flow. The standard deviation (SD) of characteristic peaks was used to estimate the spectral valid data in this experiment. Coupled with cluster analysis, artificial neural networks and genetic algorithm are employed as a nonlinear regression method in order to indicate the relationship between coal quality and the corresponding plasma spectra. It is shown that the average absolute error of ash, volatile matter, fixed carbon, and gross calorific value for the validation set is 0.82%, 0.85%, 0.96%, and 0.48 MJ/kg. The average standard deviation of repeated samples is 1.64%, 0.92%, 1.08%, and 0.86 MJ/kg, showing a high sample-to-sample repeatability. This rapid coal analyzer is capable of performing reliable and accurate analysis of coal quality.

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Elemental analysis of coal by means of the Laser Induced Breakdown Spectroscopy (LIBS) technique

Cited by 21 publications

References 3 publications

Spectroscopic investigations of the laser induced thallium plasma

Spectroscopic investigations of the laser induced thallium plasma

Effects of Microwave Irradiation on Combustion and Sodium Release Characteristics of Zhundong Lignite

Development of a Rapid Coal Analyzer Using Laser-Induced Breakdown Spectroscopy (LIBS)

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