Biofuels & Bioenergy

Biography

Biography: Du Zexue

Abstract

Glycerol is the main byproduct in biodiesel production by recycled restaurant greases that cannot be purified as medicinal glycerol,because of its some harmful impurities, but can be transformed to valuable oxygenated fuel additives through etherification with isobutene from C4 petrochemical fraction. The etherification of glycerol with isobutene has been studied over different acid catalysts was studied under the diffrent conditions.A multivariate analysis has been used to assess the conditions (isobutene /glycerol molar ratio,reaction time and temperature) that yield the best catalytic results in terms of glycerol conversion and selectivity towards the di- and tri-derivates(DTBG and TTBG), while minimizing the formation of the monoderivate compound (MTBG) and the extension of the butylene di/trimerization. Results proved formation of MTBG , DTBG and TTBG, as a result of its etherification with isobutene over acid catalysts. Glycerol fractional conversion values and di/tri-ether selectivity values approaching to 100% and 95% respectively were highly promising. Glycerol etherification results obtained by using i-butene as the reactant, proved the importance of acidic strength of the catalyst, as well as the pore diffusion resistance,on the catalytic performance. A special acid catalyst, with very high dispersity of acid sites, showed excellent performance in catalyzing glycerol with i-butene ,and the selectivity value of the butylene di/trimerization is reduced to less than 5%. Laboratory tests using a blend containing the glyceryl di/tri-ethers in petroleum diesel showed reduction of pour and cloud points, indicating the potential of these ethers as bioadditives to automobile fuels.Results proved that etherification of the by-product from the biodiesel fed the recycled restaurant greases glycerol could be successfully achieved by using isobutene C4 petrochemical fraction, to improve the economics of biodiesel production.