Asphaltene Surface Erosion in Air Plasma

• Published in: Plasma science & technology Vol. 12; no. 1; pp. 81 - 86
• Main Authors: Villa, M, Calixto-Rodriguez, M, Martinez, H, Poveda, J. C, Reyes, P. G, Altuzar, P
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.02.2010
• Subjects: Air plasma; Asphalts; Density; Electrodes; Erosion; Etching; Exposure; Monitors; Weight reduction
• ISSN: 1009-0630
• DOI: 10.1088/1009-0630/12/1/17

Optical emission spectroscopy was applied for plasma characterization during erosion of substrates of asphaltene. The amount of 100 mg of asphaltene was carefully applied to an electrode and exposed to air plasma glow discharge at a pressure of 1.0 Torr. The plasma was generated in a stainless steel discharge chamber by an AC generator with a frequency of 60 Hz and an output power of about 60 W. The electron temperature was found to be 6.88 eV, and the ion density is about 3.5 X 1016 cm-3. As the asphaltene was exposed to the air plasma, the surface was etched. The emission from molecular bands CS2, O3, N2+, NO, O2, CS, S2, CN, C7H7, C2, H2, C2-, NiO, N2 and SO, and atomic line O, were observed and some of them were used to monitor the evolution of asphaltene erosion. The asphaltene weight was reduced gradually with an etching rate of about 0.844 mg/min, during the first 20 min.