Process for the conversion of a solid material containing hemicellulose, cellulose and lignin

A process for the conversion of a solid material containing hemicellulose, cellulose and lignin, wherein the process comprises the following steps:

• (i) hydrolyzing, at a temperature equal to or less than 40° C. at least part of the hemicellulose of the solid material by contacting the solid material with a first aqueous hydrochloric acid solution, wherein the first aqueous hydrochloric acid solution has a hydrochloric acid concentration in the range from equal to or more than 15.0 wt. % to less than 40.0 wt. %, based on the weight amount of water and hydrochloric acid in the first aqueous hydrochloric acid solution, yielding a remaining solid material and an aqueous first hydrolysate product solution;
• (ii) displacing the aqueous first hydrolysate product solution from the remaining solid material with a non-aqueous displacement fluid;
• (iii) hydrolyzing, at a temperature equal to or less than 40° C. at least part of the cellulose of the remaining solid material by replacing the non-aqueous displacement fluid with a second aqueous hydrochloric acid solution, wherein the second aqueous hydrochloric acid solution has a hydrochloric acid concentration in the range from equal to or more than 40.0 wt. % to equal to or less than 51.0 wt. %, based on the weight amount of water and hydrochloric acid in the second aqueous hydrochloric acid solution, yielding a residue and an aqueous second hydrolysate product solution,
• wherein process step (i) is carried out in at least one reactor of cylindrical shape, and
• wherein said non-aqueous displacement fluid comprises an inert gas or an inert, hydrophobic liquid having a density equal to or less than 1000 kilograms per cubic meter (kg/m3), and
• wherein the non-aqueous displacement fluid is supplied to the reactor at the top of said one or more reactors, pushing out said aqueous first hydrolysate product solution at the bottom from said one or more reactors.