The 6th International Conference on Biomass Energy (ICBE2018)

337 / 2018-07-31 01:29:12

Recycle and reuse performance of the concentrated phosphoric acid plus hydrogen peroxide (PHP) pretreatment solvent system towards building a more sustainable lignocellulose biorefinery

Plenary track > C. Liquid Biofuel

In a typical lignocellulose biorefinery, the recycle and recovery ability of the spent solvent or chemical is influential on the overall economic performance of the final product. A good example was that the successful development and application of the recovery boiler set a milestone for modern Kraft pulping process. Our previous work has shown that phosphoric acid plus hydrogen peroxide (PHP) pretreatment could greatly deconstruct recalcitrant cellulose structure while removing hemicellulose and lignin component for a wide range of biomass species. After PHP pretreatment, the resulting cellulose were highly accessible to hydrolytic enzymes and feasible for the subsequent fermentation process for bioethanol production even at high solid loadings. However, the high amount of phosphoric acid usage and potential phosphorus emission challenges its applications at pilot scale. This work assessed the recycle and reuse performance of the spent concentrated phosphoric acid towards building a more sustainable lignocellulose biorefinery. Our initial results showed that among the three testing solvents, ethanol was more feasible for assisting the fractionation process, likely due to its stronger phosphoric acid solubility. Phosphoric acid recovery was higher than 83.7% even after 10 times of recycle process. The extent of deligninification, cellulose recovery, glucose yield resulting from the recycled PHP solvent system were comparable to that from fresh PHP solvent. This works shows that phosphoric acid could be recycled using the facile vacuum distillation through removing ethanol co-solvent, which could lower the investment of chemical input and potentially facilitate the development of the nascent PHP biorefinery concept.