Detection and quantification of sulfur in oil products by laser-induced breakdown spectroscopy for on-line analysis

• Published in: Spectrochimica acta. Part B: Atomic spectroscopy 2016-04, Vol.118, p.72-80
• Main Authors: Trichard, F., Forquet, V., Gilon, N., Lienemann, C.-P., Baco-Antoniali, F.
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Calibration; Chemical Sciences; Flow rate; Helium; Laser induced breakdown; LIBS; On-line systems; Optimization; Petroleum products; Process on-line analysis; Spectroscopy; Sulfur
• ISSN: 0584-8547; 1873-3565
• DOI: 10.1016/j.sab.2016.02.001

Determination of sulfur in petroleum products is described using Laser Induced breakdown spectroscopy (LIBS). A study of buffer gases employed to improve sulfur IR line detection is presented. Optimisation of the flow rate led to a 1.4L/min optimal helium flow rate. An adaptation between a typical laboratory setup to a compact system allowed to obtain detection limits in the 0.2% w/w range. Calibration is made under the process conditions (70°C) and at room temperature. Normalization with a helium emission line compensates for liquid level variations and for the temperature variations. The analysis of a sample over the course of 2days under the conditions of the industrial process was tested and gave a good repeatability. •We optimized LIBS system for sulfur detection using NIR lines.•We examine different gases to improve signal and provide a 0.3% detection limit in petroleum products•A comparison of normalization signals is presented leading to a helium line selection.•This normalization compensates efficiently for sample temperature variations (20 to 70°C) and sample to optics distance variations