Diesel Adulteration Detection Using Gaseous Vapor Emission

Abstract

Diesel adulteration is the illegal or unauthorized introduction of foreign substances into pure diesel,
causing the product to not conform to the requirements and specifications for use in the Oil and Gas
Industry. Current methods to detect diesel adulteration require chemical laboratory experiments to
measure parameters such as density, API gravity, viscosity, flash point, and evaporation point. These
methods require specialized, expensive equipment and cannot be utilized be quickly and readily
employed at point of sale terminals (POS) prior to product purchase. Gaseous Vapor Emission (GVE)
is a relatively new technique that analyzes the gaseous vapor emissions released by samples of
petroleum products to detect the presence of adulterants, if any. The technique is portable, and can be
used to detect adulteration at POS terminals such as fuel stations. GVE was performed on a 1 L
sample of pure diesel obtained from a Nigerian National Petroleum Corporation (NNPC) retail
outlet. Results showed that in an enclosed space of approximately 19,000 cm3, pure diesel emitted
17.52–46.58 ppm of methane, 5.35–11.93 ppm of LPG, 35.51–84.6 ppm of butane, and 10.38–26.59
ppm of toluene. The emission concentrations these four gases attained their peak within 10–20
seconds of diesel exposure to open air. The timing and characteristics of these emissions serve as the
chemical signature of pure diesel for GVE testing, and was successfully utilized to detect samples of
unadulterated diesel. The reported GVE chemical signature for pure petrol is different from that
observed by pure diesel. Future work involves exploiting this difference to distinguish between pure
and petrol-adulterated diesel at Point of Sale (POS) terminals. Future work also involves obtaining
the GVE chemical signature for kerosene for detection of kerosene-adulterated diesel at POS
terminals.