National formulations of high-octane gasoline. Case study

Abstract

High-capacity anti-knock gasolines (Research Octane Number, RON ≥ 98) do not abound in the world market. They are generally “hand-made” gasoline for specific purposes, with hydrocarbon, oxygenated compounds and chemical additives, carefully selected. The objective of this work was the formulation one or more variants of gasoline ≥ 98 RON (G98), based on nationally produced gasoline and imported gasoline (in segregated form); with addition of non-metallic octane enhancing substances: pure hydrocarbons and oxygenated compounds. High-octane gasoline was obtained from refineries with Catalytic Cracking and Catalytic Reforming technologies, respectively. The volumetric contents of gasoline were selected taking into account the usual balances of products in these refineries. Proportions of hydrocarbons and oxygenates that constitute a worldwide practice were chosen. The experimental determination of the RON wascarried out in a standardized CFR-48 engine, with a single cylinder, as established by ASTM D2699. The formulation of G98, from naphtha, was achieved by adding 10 %v/v anhydrous ethanol to a base mixture reinforced with an iso-paraffin and an aromatic. G98, with imported gasoline, was obtained only with 10 %v/v ethanol. The anti-knock capacity of the rest of the formulations confirmed the complex behavior of gasoline during combustion in internal combustion engines, including the inverse proportionality between the number of carbon atoms in alcohols and the speed of initiation of chain reactions of free radicals during combustion.