Evert van der Heide

Furfural—A Promising Platform for Lignocellulosic Biofuels

Furfural offers a promising, rich platform for lignocellulosic biofuels. These include methylfuran and methyltetrahydrofuran, valerate esters, ethylfurfuryl and ethyltetrahydrofurfuryl ethers as well as various C(10)-C(15) coupling products. The various production routes are critically reviewed, and the needs for improvements are identified. Their relative industrial potential is analysed by defining an investment index and CO(2) emissions as well as determining the fuel properties for the resulting products. Finally, the most promising candidate, 2-methylfuran, was subjected to a road trial of 90,000 km in a gasoline blend. Importantly, the potential of the furfural platform relies heavily on the cost-competitive production of furfural from lignocellulosic feedstock. Conventional standalone and emerging coproduct processes-for example, as a coproduct of cellulosic ethanol, levulinic acid or hydroxymethyl furfural-are expensive and energetically demanding. Challenges and areas that need improvement are highlighted. In addition to providing a critical review of the literature, this paper also presents new results and analysis in this area.

Pretreatment of hardwood chips via autohydrolysis supported by acetic and formic acid

Abstract A mixture of US southern hardwood chips was treated with aqueous acetic and formic acid (FA) solutions in a modified Dionex ASE100 extractor. The amount and selectivity of hemicelluloses dissolution increase at higher acetic acid (AA) and FA concentrations, but cellulose remains intact in the residual wood. Even at the highest AA concentration of 100 g l-1, the dissolved hemicellulose fragments are still oligomeric except for arabinose. The formation of lignin-like condensation products (LCPs) and decomposition of dissolved mannose, arabinose, and galactose were observed at the highest AA concentration. Sugar hydrolysis is more pronounced with the addition of FA at increasing temperature. The concentration of xylose in the FA extract is approximately the same as that of xylo-oligomers at 160°C. Formation of LCPs is only observed at 170°C during 10 g l-1 FA treatment. The concentrations of dissolved wood components increase linearly with increased recycling of the FA extract.

Single-Stage Pulping of Sugarcane Bagasse with Peracetic Acid

Abstract Sugarcane bagasse was delignified by a single-stage peracetic acid (PAA) pulping process. It was found that temperature, pulping time, PAA loading, and liquor ratio all had very significant effects on pulp yield, kappa number (KN), degree of delignification, and holocellulose degradation. The optimum condition for single-stage PAA pulping was as follows: temperature of 75°C, PAA loading of 50%, liquor ratio of 4:1, and pulping time of 2 h. Under this condition, pulp with 53.7% yield, 11.3 kappa number, 51.12% ISO brightness, and 900 degree of polymerization were obtained. Compared with a kraft process, single-stage PAA pulping could obtain higher pulp yield and brightness, lower kappa number, and less degradation of carbohydrates. However, more chemicals were consumed in PAA pulping and the degree of polymerization of the pulp as well as some mechanical properties were a little lower than that of kraft pulp. Fourier transform infrared (FTIR) analysis indicated that PAA pulp had a lower lateral order index (LOI) and higher infrared crystallization index than kraft pulp. X-ray diffraction (XRD) analysis showed that the two pulps had similar pulp crystallinity index, and kraft pulp had a larger average crystallite size than PAA pulp.