Comparison of the Effects of Different Biofuels on the Oxidation Stability of a Hydrocarbon Fuel

Abstract

In this work, the effects of the addition of biofuels belonging to different chemical families on the oxidation stability of a conventional fuel surrogate (n-decane) have been investigated. Experiments have been performed in a PetroOxy apparatus, which is one of the reference Rapid Small Scale Oxidation Test of the ASTM 7545 methods. When the pressure in the cell of the device decreases by 10% of the maximum pressure recorded, the time measured to reach this target value defines the Induction Period (IP). IP constitutes a quantitative measure of the oxidation stability of the fuel. In addition to the IP measurements for each biofuel / hydrocarbon fuel blend, organic peroxides produced in the liquid sample were quantified at the IP, using iodometric titration and ultraviolet-visible spectrophotometry.Different oxygenated biofuels have been studied in this work: diethyl ether, n-butanol, and cyclopentanone. Cyclohexane addition has also been considered to probe the effects of a non-oxygenated additive. For each type of biofuel, the proportion added to n-decane, the surrogate fuel, was varied from 0.2 to 20%vol. For each blend, the IP and the total peroxide content in the liquid have been systematically measured.This study demonstrates an unexpected diversity of the effects of oxygenates biofuels: n-butanol strongly enhances the oxidation stability of the surrogate fuel (up to a factor of 6) while diethyl ether and cyclopentanone decrease the stability of n-decane. The experimental results show also that variations in the proportions of biofuel additives lead to non-linear variations in the measured IPs. Organic peroxide measurements confirmed that a similar reaction mechanism underpins the oxidation of all the biofuel/fuel surrogate blends.

Antioxidant effect of 2–4 xylenol on fuel oxidation in liquid and gas phase over a wide temperature range

“…It allows a fast oxidation test, which has shown to agree very well with other normalized test in Rancimat [27]. A detailed description of the petroOxy and of the experimental procedure can be accessed elsewhere [28]. The core part is a gold-plated test cell, whose volume is 25 ml and which be considered as a closed batch reactor.…”

Development of a Detailed Kinetic Model for the Oxidation of n-Butane in the Liquid Phase

“…Oxidation stability of biofuels is also a key current research field as oxygenated molecules generally have lower oxidation stability compared to hydrocarbons. 6,7 Detailed chemical kinetic modeling of the autoxidation of fuels remains the only approach to provide fundamental insights into the underlying oxidation chemistry. However, the development of such kinetic models, rigorously adapted to the liquid phase, is scarce in the literature.…”

“…The understanding of their autoxidation chemistry is therefore of primary importance. Oxidation stability of biofuels is also a key current research field as oxygenated molecules generally have lower oxidation stability compared to hydrocarbons. , …”