[304912] Artigo – CBM – Congresso Brasileiro de Metrologia

Resumo: Monitoring the adulteration of fuels is a matter of interest as a means of protecting consumers, preventing fraud and protecting the environment. In Brazil, commercialized gasoline is a mixture of fuel with 27% anhydrous ethanol, called C gasoline. As a misleading practice, larger fractions of ethanol and organic solvents are used. Laboratory analyses are necessary to detect this irregularity, making inspection actions more difficult. Given the above, the article proposes using ultrasound to identify gasoline adulteration as an alternative method. Different samples were used: pure gasoline, gasoline with ethanol prepared for the study (gasoline C) and mixtures with kerosene. The study was based on measuring two monitoring parameters: propagation velocity and experimental attenuation. Ultrasound transducers with central frequencies 1 MHz and 5 MHz were used in the pulse-echo method. Paired comparisons (t-tests) were performed to assess whether the use of ultrasound was sensitive to changes in the medium with the addition of solvent. The experimental attenuation showed a statistical difference compared to gasoline without kerosene, proving to be a good parameter to be monitored. For the propagation speed, only the samples with 20% and 30% of kerosene and with the 1 MHz transducer proved adequate to the proposed method.