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Low‐temperature flow properties of vegetable oil/cosolvent blend diesel fuels
Author(s) -
Dunn R. O.
Publication year - 2002
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-002-0547-x
Subject(s) - pour point , cloud point , diesel fuel , vegetable oil , methanol , chemistry , alcohol , butanol , biodiesel , chemical engineering , viscosity , biofuel , thermodynamics , organic chemistry , ethanol , materials science , extraction (chemistry) , waste management , composite material , catalysis , physics , engineering
Vegetable oils are an attractive renewable source for alternative diesel fuels. However, the relatively high kinematic viscosity of vegetable oils must be reduced to make them more compatible with conventional compression‐ignition engines and fuel systems. Cosolvent blending is a low‐cost and easy‐to‐adapt technology that reduces viscosity by diluting the vegetable oil with a low‐M.W. alcohol (methanol or ethanol). The cosolvent ( A ), which consists of one or more amphiphilic compounds, is added to solubilize the otherwise nearly immiscible oil‐polar alcohol mixture. This work investigates cold flow properties and phase equilibrium behavior associated with blends consisting of soybean oil (SBO) and methanol where A =8∶1 (mol) n ‐butanol/oleyl alcohol; 6∶1 (mol) 2‐octanol/triethylammonium linoleate; and 4∶1 (mol) 2‐octanol/Unadol 40 (alcohols from SBO FA); and a blend of 2∶1 (vol/vol) No. 2 diesel fuel/SBO and 95% ethanol where A = n ‐butanol. Cloud point (CP), pour point, cold filter plugging point (CFPP), and low‐temperature flow test (LTFT) results were compared with corresponding phase separation temperature ( T ϕ ) data measured at equilibrium. Although CP data were measured under non‐equilibrium experimental conditions, a nearly linear correlation was found between T ϕ and CP. Statistical analysis showed that T ϕ may also be correlated with CFPP and LTFT. Analysis of heating and cooling DSC curves indicated that peak temperatures may be employed to predict cold flow properties and T ϕ behavior for SBO/cosolvent blends. Cooling curve parameters correlated more readily than heating curve parameters. Finally, relatively low quantities of heat evolved during freezing indicated that crystallization in the SBO/cosolvent blends studied in this work occurs easily during cooling.