Experimental study on mercury content in flue gas of coal-fired units based on laser-induced breakdown spectroscopy

Abstract

Accurate measurement of trace heavy metal mercury (Hg) in flue gas of coal-fired units is great significance for ecological and environmental protection. Mixed gas was used to simulate the actual flue gas of a power plant in this study. A laser-induced breakdown spectroscopy (LIBS) system for Hg measurement in mixed gas was built to study the effect of mixed gas pressure, Hg concentration in mixed gas and delay time on Hg measurement. The experimental results show that the appropriate low mixed gas pressure can obtain high Hg signal intensity and signal to noise ratio. The Hg signal intensity and signal to noise ratio increased with the increase of Hg concentration in mixed gas. The Hg signal intensity and signal to noise ratio decreased with the increase in delay time. According to the above results, the optimized measurement conditions can be determined. Different Hg concentrations in mixed gas were quantitatively analyzed by the internal standard method and traditional calibration method respectively. The relative error of prediction of the test sample obtained by the internal standard method was within 11.11%. The relative error of prediction of the traditional calibration method was less than 14.54%. This proved that the internal standard method can improve the accuracy of quantitative analysis of Hg concentration in flue gas using LIBS.

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

“…Rong et al , undertook an experimental study of Hg in flue gas based on LIBS . 68 The Hg from coal burning plants is discharged into the atmosphere together with the flue gas. The Hg in the atmosphere has toxic persistence and bioaccumulation effects which can cause harm to human health and the environment.…”

Highly Sensitive Detection of Heavy Metal Elements Using Laser-Induced Breakdown Spectroscopy Coupled with Chelating Resin Enrichment

“…By collecting and analyzing the characteristic spectral information, the target samples can be qualitatively and quantitatively analyzed [14]. For the case of LIBS, the ablation is not limited by the sample's physical state and can be directly applied to the detection of solid [15], liquid [16], gas [17], and aerosol [18] samples. However, the direct action of a laser on liquid samples causes many problems, including liquid sputtering, liquid level fluctuation, laser energy loss, and so on [19].…”

Way-out for laser-induced breakdown spectroscopy

“…It is worth mentioning that variable selection is an important way to improve the quantification performance and has attracted more interest [12][13][14]. The application not only included steel classification [17], aluminum alloy analysis [14], coal analysis [12,16], geographical authenticity evaluation [18], and plants classification [15], but also included some new or uncommon application fields such as uranium measurements [19], mercury measurements [20], soil pH measurements [13], and rock salt analysis [21]. Overall, in ASLIBS, there was a wide range of LIBS applications presented, which was quite reasonable considering large market potentials exist in Asian countries, especially in China [22].…”