[303400] Artigo – CBM – Congresso Brasileiro de Metrologia

Resumo: Liquefied Petroleum Gas (LPG) is a versatile and widely used fuel that is crucial in various sectors. Its significance as a combustible gas stem from its high energy content and ease of storage and transportation. Its lower environmental impact than other fossil fuels further enhance its appeal as a cleaner energy alternative. This fuel finds extensive applications in industries, commercial establishments, and agricultural activities, which sheds light on its measurement systems. Based on the calculation algorithms for LPG mass, which is the trading unit of the product, and the regulatory ordinance, this study aimed to evaluate the critical factors that impact the calculation of the mass measurement in a dynamic measuring system. This work introduces the measurement function for mass calculation and the associated uncertainty calculation. Furthermore, it presents the concept and functioning of a measuring system, along with the critical factors and associated quantities, which significantly impact the calculation of the expanded uncertainty of LPG mass: correction factors for the effects of pressure, density, and temperature. Approximately, these factors have, respectively, the following weights in the total uncertainty value, based on the arithmetic average of the conducted experiments: 45 %, 43 % and 9 %. The study concludes that the prescribed uncertainty limits established by the Brazilian Institute of Metrology, Quality, and Technology regulations for secondary (or associated) quantities have limited practical significance. It occurs because all indications suggest that the uncertainty values exceeding the prescribed limit for individual uncertainty can still meet the maximum uncertainty of the output variable – LPG mass – which is the crucial aspect. Lastly, a future study to optimize individual acceptance criteria calibration is proposed.