2.2.2. Scenario 2. Furfural production
The furfural production includes three stages: autohydrolysis of bagasse, dehydration of xylose and distillation of furfural. Autohydrolysis was described in item 2.1. The conversion of xylose to furfural is performed by acid hydrolysis with H2SO4. The conversion conditions were established on the basis of a study carried out by Montastruc et al. (2011). Furfural-water mixture is separated by azeotropic distillation (Hoydonckx et al., 2007). A mixture of approximately 30% of furfural is obtained as the distillate of the first distillation column. This cooled distillate is sent to decanters, where furfural is separated spontaneously into a furfuralpoor and a furfural-rich phases. Liquid–liquid extraction is possible because the limited solubility of furfural in water (8.3 wt.% at 20 ◦C). The boiling point of furfural is 161.7 ◦C
at 1 atm., whilst that of the azeotrope is 97.9 ◦C, so both columns operate at 98 ◦C (Montastruc et al., 2011). The H2SO4 is sent to recover for recycle and reuse in further hydrolysis using ion-exchange column with the conditions established by (Kumar et al., 2015) (not included in this study).