Dilute acid hydrolysis of lignocellulosics: An application to medium consistency suspensions of hardwoods using a plug flow reactor

A one‐stage process for the high temperature rapid dilute acid hydrolysis of hardwoods, to produce simultaneously furfural and fermentable sugars, is described. A continuous plug flow reactor unit designed to hydrolyse medium consistency wood suspensions (up to 13% w/w in solids) has been operated at capacities up to 90 kg/h, with temperatures ranging from 190°C to 240°C and 20‐120 s as residence times. The final products, mainly furfural and sugars, have been analyzed using high performance liquid chromatography. Yields of 15 kg of hexoses (30% of the theoretical potential) and 10 kg of furfural (65% of the theoretical potential) for 100 kg of sawdust (dry basis) have been obtained. Two pseudokinetic modeis were used to simulate the pentosan and hexosan acid hydrolysis reactions. A Flowtran Simulation has been conducted resulting in mass and energy balances for an eventual industrial unit.