Integrated production of furfural and second-generation bioethanol from Eucalyptus wood residues: experimental results and process simulation

In this study, furfural production in a two-stage system was investigated using Eucalyptus wood residues (pinchips) as raw material. Firstly, an autohydrolysis treatment at 170 degrees C was performed for 40 min to solubilise xylosaccharides from biomass. In a second stage with sulphuric acid, furfural production was evaluated at different temperatures (170-240 degrees C) and reaction times (2.5-30 min) with two acid concentrations (0.3 and 3.0% w/w). The maximum furfural yield achieved was 77.4% of the theoretical production, considering the solubilised xylosaccharides content in the autohydrolysis liquor. This condition was achieved at 210 degrees C for 10 min with a sulphuric acid concentration of 0.3% w/w. The biomass pretreatment was a two-stage pretreatment with the above autohydrolysis followed by a soda-pulping stage of the solid fraction at 155 degrees C and 7.8 atm for 90 min using a 2.4% w/w NaOH solution. These results were added to previous experimental results for bioethanol production by enzymatic hydrolysis and fermentation to develop the process design. A lignocellulosic biorefinery plant co-producing furfural (from the hemicellulosic fraction) and bioethanol (from the cellulosic fraction) was proposed and simulated using Aspen Plus (R) V11. According to the material balance results, the proposed plant processes 166 tonne/d of Eucalyptus pinchips, with a production capacity of 203 tonne/d of bioethanol and 35 tonne/d of furfural. Finally, 33.0 MW of hot and 15.2 MW of cold utilities are required for the proposed process according to the heat integration analysis.

Automated summary

This study investigated the production of furfural using Eucalyptus wood residues as raw material in a two-stage system. The maximum furfural yield achieved was 77.4% of the theoretical production. The results were used to propose a lignocellulosic biorefinery plant co-producing furfural and bioethanol. According to heat integration analysis, the proposed process requires a certain amount of hot and cold utilities.