Production of furfural from an industrial pre-hydrolysis liquor

• An industrial pre-hydrolyzate was used as the feed stock for furfural production.
• Removal of lignin by activated carbon had positive effect on the furfural production.
• An overall process concept of furfural production from PHL was proposed.

Pre-Hydrolysis Liquor (PHL) produced from the prehydrolysis kraft-based (PHK) dissolving pulp production process can be considered as a potential source for the production of biomaterials and biochemicals. Several dissolved organics such as hemicelluloses, lignin and acetic acid can be recovered and converted to valuable products. Xylan/xylose, a 5-carbon sugar and the major component of the hardwood PHL can be utilized to produce furfural. Pretreatment is necessary to increase the furfural yield, mainly by removing lignin, facilitating processing and minimizing the side reactions. In this research, adsorption by activated carbon, ion exchange resin treatment, and concentration by membrane filtration were utilized as pretreatments of PHL for furfural production. It was found that a furfural yield of 57% was achieved from the PHL at 190 °C, using sulfuric acid as a catalyst. An overall process, integrated into the existing PHK dissolving pulp production process, was proposed to produce furfural from the PHL which fits well to the Integrated Forest Biorefinery concept.