Furfural production from a pre-hydrolysate generated using aspen and maple chips

Abstract

This paper focuses on the production of furfural from a simulated kraft dissolving pulp mill pre-hydrolysate solution that is rich in pentoses. Presently, this stream at the mill is mixed with the black liquor and then burned to recover some of the energy needed for the process. However, this pre-hydrolysate would have a higher potential if used as a feedstock for furfural production. This work demonstrates a novel approach to produce furfural in high yields by adding the catalyst only when the desired reaction temperature is reached, and by removing the furfural as soon as it is generated in the reactor. By applying this concept on the pre-hydrolysate, a furfural yield of 76% can be obtained at 240 °C and 2.5 kg m−3 of sulfuric acid. In other approaches where the acid is initially mixed with the pre-hydrolysate, furfural yield varies between 54 and 65% depending on whether furfural is left in the reaction medium or removed as it is formed, respectively.Maximization of furfural production has also been studied in this work by varying the sulfuric acid dosage (1–5 kg m−3) and the reactor temperature (160–260 °C). The highest furfural yield of 77.6% can be obtained when a sulfuric acid concentration of 3.6 kg m−3 and a temperature of 240 °C are used for the pre-hydrolysate solution. When lignin is removed from the pre-hydrolysate prior to furfural production, the highest furfural yield is 72.6% at 220 °C and 3.6 kg m−3 of sulfuric acid.