Preparation of ethanol and palm oil/palm kernel oil alternative biofuels based on property improvement and particle size analysis

Abstract

With the continuous rise in fuel prices and the depletion of fossil fuel resources, the alternative biofuel which has good stability and is suitable for engine combustion is the focus of scientists' research. In this study, the method of mixing ethanol with palm oil (PO) and palm kernel oil (PKO) was used to improve the shortcomings of PO/PKO, such as high surface tension, high density and viscosity. Five co-solvents with a biological production background are selected: tetrahydrofuran (THF), polyoxymethylene dimethyl ether (PODE) and three butanol isomers to aid solubility. The results show that with the continuous dripping of the co-solvent, the PO/PKO and the ethanol gradually dissolve each other until the emergence of a single-phase liquid. Among the five co-solvents, the order of solubilization is THF > PODE > n-butanol > 2-butanol > iso-butanol. Also, with the increase in temperature, the solubility-assisting ability increases. When the particle size of the ternary blended fuel microemulsion system reaches the maximum value of 59.65 nm, the composition ratio of ethanol in the basic system is 50%. In addition, PKO has a stronger affinity with ethanol than PO; PKO can be completely miscible with ethanol when the experimental temperature is 35 °C. As the proportion of ethanol increases, the surface tension of the ternary system decreases by 36.2% at most. In terms of fuel property adjustment, THF has the best adjustment effect on solubility and viscosity. Butanol has the best adjustment effect on the density of blended fuel. PODE will corrode copper strips due to high oxygen content. In the future, according to the fuel demand in different scenarios, the proportion of each component in the blended fuel can be adjusted to achieve the optimum in practical applications.