Optimization of Pre-esterification for Biodiesel Production from Waste Fried Oil through Response Surface Methodology
Date Issued
2010
Date
2010
Author(s)
Tsai, Di-Yang
Abstract
Acid value indicates amounts of free fatty acid in wasted fried oil. When the acid value above 1 mg KOH/g, high level of free fatty acid causes soap formation, thus reducing ester yield of biodiesel in the transesterification process for biodiesel production.
In order to reduce the soap formation and increase the ester yield in biodiesel production process, to reduce the acid value of wasted fried oil is preferred. This procedure is termed pre-esterification process. The purpose of this study is to identify the optimal operating condition furing the pre-esterification process using wasted fried oil with three levels of acid value. The four factors and five levels central composite design (CCD) of the response surface methodology (RSM) was employed to evaluate the effects of methanol/oil molar ratio, catalyst amount, reaction temperature and reaction time on the efficiency of pre-esterification and the amount of reduction of the acid value of wasted fried oil.
The results show that the lowest acid value obtained were 0.52 ± 0.02, 0.73 ± 0.02 and 0.83 ± 0.02 mg KOH/g equivalent to 76%, 84% and 85% pre-esterification efficiency when original acid value of wasted fried oil were 2.21, 4.42 and 5.45 mg KOH/g respectively. The R-square of regression models were 0.70、0.63 and 0.61 respectively.
Subjects
biodiesel
waste fried oil
acid value
optimization of pre-esterification
response surface methodology
Type
thesis
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