Feasibility of integrating hot water extraction into a dissolving pulp process to recover hemicelluloses from Pinus radiata

Hot water extractions using Pinus radiata sawdust as raw material were performed both at laboratory and pilot scales to investigate their feasibility with a view to scaling up the extractions to an industrial process. The laboratory scale extractions were performed at 160 °C, 170 °C and 180 °C, for up to 100 minutes without adjustment of pH. The pilot scale extractions were done at 160 °C and 170 °C for 40 min. Additionally, the pilot scale extractions were also performed at 150 °C, 160 °C and 170 °C with a P-factor of 600. The highest yield obtained in the pilot scale extractions was 112.6 mg/g at the extraction temperature of 170 °C with the P-factor of 600. It was proved that it is feasible to scale up the hot water extraction from laboratory to pilot scale, but the extraction parameters must be tuned to achieve a high extraction yield of carbohydrates.