Low-temperature phase behavior of vegetable oil/co-solvent blends as alternative diesel fuel

摘要: Vegetable oils (triacylglycerols) have many characteristics that make them attractive candidates as renewable alternative fuels for compression-ignition (diesel) engines. Unfortunately, vegetable are too viscous to be compatible with modern direct-injection diesel fuel systems and Co-solvent blending is a simple flexible technology reduces viscosity by mixing the oil low molecular weight alcohol. A co-solvent (A), consisting, of surfactant plus an amphiphilic compound, added solubilize otherwise nearly immiscible oil-alcohol mixtures into single-layer (isotropic) solution. This work examines low-temperature phase behavior two soybean (SBO)/methanol solubilized A=unsaturated long-chain (C18) fatty alcohol/medium-chain alkanol (n-butanol 2-octanol), one SBO/methanol mixture A=triethylammonium linoleate/2-octanol, SBO/95 wt% ethanol (E95) n-butanol. The E95-blend was further blended in 1∶1 (vol/vol) No. 2 fuel. Two types anisotropic were observed; formation cloudy layer solid crystals suspended bulk solution (Type 1) liquid layers II). type separation given influenced temperature (Tϕ) relative crystallization compounds SBO alcohol or amine constituents present Solutions relatively Tϕ values experienced small particles favoring Type 1 separations. Conversely, solutions sufficient avert high melting point favored II separations where Tϕ=critical (Tcritical). Increasing A/oil (SBO diesel/SBO mixture) mass ratio decreased while increasing fraction (methanol E95) increased Tϕ. shows oil/A-based blends can formulated cold flow properties superior respect cloud comparable kinematic (v) methyl soyate (biodiesel), either neat petroleum middle distillates.