Biodiesel Production from Castor Oil under Subcritical Methanol Conditions

Abstract

Abstract-Biodiesel is a potentially sustainably renewable fuel for diesel engines; transesterification is the most used method to produce it and high quality vegetable oils are the most usual raw material. Non-edible vegetable oils such as castor oil can provide an alternative feedstock. In this work biodiesel was obtained by transesterification of castor oil with subcritical methanol; the reaction was carried out in an hermetic reactor at temperatures higher than methanol boiling point and with a small amount of potassium methoxide as catalyst. The effect of methanol:oil molar ratios were analyzed, observing that high proportion of alcohol is needed to reach high ester content, the best results were reached with 24:1 MeOH:oil molar ratio. Regarding catalyst concentration, 8.7 mM (0.12 wt%) were enough to achieve good results. A temperature of 150 º C and 1 h of reaction, at 10 bar, were the mildest conditions to reach an ester content higher than 90 wt %. The highest ester content, 94.7 wt %, was achieved at 220 º C, 36 bar and 4 h of reaction time. Hence good quality biodiesel from castor oil can be produced in subcritical methanol conditions, using a small amount of basic catalyst.

Effect of Process Variables on the Transesterification Process of Palm Oil Sludge to Biodiesel

“…The density of palm oil sludge used for the transesterification reaction was 976 kg/m 3 . The results obtained are within the range reported in the literature (0.9625 g / ml and 0.9772 g / ml) [38]. Comparing this literature value with the density values of palm oil sludge in this research work, we concluded that there is no significance difference with values reported in the literature.…”

Total acid number reduction kinetics of naphthenic acids using non-catalytic subcritical methanol

“…However it is always desired to reduce the severity of the reaction conditions attached [13]. A much milder subcritical methanol have been the replacement for many reactions due to its high solubility in many organic and petroleum oils and feedstock [15,21,22] Here subcritical conditions of methanol have shown 59% TAN reduction at a temperature of 210°C and a reaction time of 150 min, which is comparatively higher than the results achieved by previous researchers at this temperature and time condition. Prolonging the reaction time further does not affect the TAN reduction.…”

“…>350°C and 10 MPa, respectively [13,14]. To reduce the severity of reaction conditions subcritical methanol can be an alternative as many processes have shown high conversion of free fatty acids into biodiesel using subcritical methanol [15,16].…”

Biodiesel Production from Palm Oil, Its By-Products, and Mill Effluent: A Review

“…Recently, a new type of chemical, the so-called ionic liquids (ILs), and non-catalysed routes under supercritical conditions have gained attraction among researchers [28][29][30][31]. Even though both strategies have been successfully performed on a laboratory scale, their industrial acceptance and application are still limited due to their high capital and operational cost, non-conformity of the recovery methods, low reusability of ILs, and several technical and operational challenges, including the requirement of heating instrument and high-pressure vessels resulting in high energy demand [32][33][34][35][36].…”