Biofuels & Bioenergy

Biography

Biography: Du Zexue

Abstract

Glycerol is the main byproduct in biodiesel production by recycled restaurant greases that cannot be purifi ed as medicinal glycerol, because of its some harmful impurities, but can be transformed to valuable oxygenated fuel additives by etherifi cation with isobutene from C₄ petrochemical fraction. The etherifi cation of glycerol with isobutene has been studied over diff erent acid catalysts under the diff rent conditions. A multivariate analysis has been used to assess the conditions (isobutene/glycerol molar ratio,reaction time and temperature) that yielded the best catalytic results in terms of glycerol conversion and selectivity towards the di- and triderivates (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 etherifi cation 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 etherifi cation results obtained by using i-butene as the reactant, proved the importance of acidic strength of the catalyst, as well as the pore diff usion 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 was 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 etherifi cation of the by-product from the biodiesel of the recycled restaurant greases glycerol could be successfully achieved by using isobutene C₄ petrochemical fraction, to improve the economics of biodiesel production.