Effect of Crambe abyssinica oil degumming in phosphorus concentration of refined oil and derived biodiesel

Abstract

In the present study, the effect of different degumming processes on the phosphorus content of Crambe abyssinica oil and resultant biodiesel was evaluated. The non-edible oil was submitted to water degumming and chemical degumming with different concentrations of phosphoric acid and varying the acid to oil volume percentages. Phosphorus content of the products was measured by UV spectroscopy after sample calcination, according to NP 1994:2000. Biodiesel was produced by transesterification using a 6:1 methanol to oil molar ratio and 1 wt% sodium hydroxide as catalyst at 65 degrees C, during 1 h. The biodiesel produced directly from the crude oil presented high phosphorus concentration (>20 ppm); consequently, a degumming process was required to fulfil the quality standard (<4 ppm according to EN 14214). Water degumming was not effective, leading to biodiesel with a phosphorus concentration of 12.2 ppm. Among the acid degumming processes evaluated and taking into account technical and operational variables, the best established conditions, which allowed the fulfilment of the quality standard regarding phosphorus concentration, was considered to be 25 wt% acid concentration and 0.80 vol% of acid to oil.