Elemental and proximate analysis of coal by x-ray fluorescence assisted laser-induced breakdown spectroscopy

Abstract

Accurate acquisition of coal quality information, including the chemical composition and proximate analysis results, is of great significance for coal mixing and combustion control in thermal power plants. Laser-induced breakdown spectroscopy (LIBS) is one of the potential and competitive technologies for rapid and on-line analysis of coal quality. However, due to the difficulty in controlling the stability of the generated plasmas, the measurement repeatability of LIBS needs to be further improved. In this paper, we propose a novel X-ray fluorescence (XRF) assisted LIBS method for high repeatability analysis of coal quality, which not only inherits the ability of LIBS to directly analyze organic elements such as C and H in coal, but also uses XRF to make up for the lack of stability of LIBS in determining other inorganic ash-forming elements. By combining the elemental lines of LIBS and XRF spectra, the principal component analysis (PCA) and the partial least squares (PLS) are used to establish the prediction model and perform multi-elemental and proximate analysis of coal. Quantitative analysis results show that the relative standard deviation (RSD) of C is 0.15%, the RSDs of other elements are less than 4%, and the standard deviations (SDs) of calorific value, ash content, sulfur content and volatile matter are 0.11 MJ kg-1, 0.17%, 0.79% and 0.41% respectively, indicating that the method has good repeatability in determination of coal quality. This work is helpful to accelerate the development of LIBS in the field of rapid measurement of coal entering the power plant and on-line monitoring of coal entering the furnace.

Application and Research Progress of Laser-Induced Breakdown Spectroscopy in Agricultural Product Inspection

“…To address these issues and bolster detection sensitivity, researchers are actively exploring a variety of signal enhancement methods. Techniques like spatial or magnetic confinement LIBS, nanoparticle-enhanced LIBS, double-pulse or multipulse LIBS, resonance-enhanced LIBS, and laser-induced fluorescence-assisted LIBS, − have been introduced. These approaches aim to optimize the interaction between the laser and the sample, enhance the spectral signals generated and emitted by the plasma, thereby amplifying both LIBS signal intensity and stability.…”

Atomic spectrometry update: review of advances in the analysis of metals, chemicals and materials

“…Tian et al looked to use combined LIBS and XRF to improve the repeatability of proximate analysis of coal in thermal power plants . 87 The LIBS was used for the determination of C and H and XRF for the determination of the inorganic ash forming elements. This improved stability compared with using LIBS for the whole analysis.…”

A new stage of the Asian laser-induced breakdown spectroscopy community

“…This special issue is to memorialize the 4th ASLIBS and the ten-year anniversary of CSLIBS, and to mark a starting point for the next stage of growth of ACLIBS and CSLIBS. It collected nine research articles covering fundamental [5], instrumentation [6], data processing [7,8], and application [9][10][11][12][13] studies. The effects of lens-to-sample distance on plasma morphology and spectrum using a flat-top laser beam were investigated [5]; a LIBS-assisted glow discharge method for liquid samples was developed [6]; a support vector machine combined with restricted Boltzmann machine was proposed for steel classification [7]; and plasma images were utilized to reduce the spectral fluctuation in combustion environments [8].…”

“…The effects of lens-to-sample distance on plasma morphology and spectrum using a flat-top laser beam were investigated [5]; a LIBS-assisted glow discharge method for liquid samples was developed [6]; a support vector machine combined with restricted Boltzmann machine was proposed for steel classification [7]; and plasma images were utilized to reduce the spectral fluctuation in combustion environments [8]. The other five articles focused on the applications, including the quantitative analysis of ceramic raw materials [9], the identification of mural pigments [10] and volatile organic compounds [11], the determination of aqueous ruthenium by microwave-assisted LIBS [12], and the quantitative analysis of coal by X-ray fluorescence (XRF) assisted LIBS [13].…”