Hydrothermal processing of biomass for renewable energy and chemical materials

Abstract Many countries are currently searching for alternative and renewable energy sources (such as biomass, solar, wind, or hydro power) to replace the polluting fossil fuels. The burning of large amounts of fossil fuels worldwide has contributed to global warming and adverse weather conditions in many countries and regions. One potential candidate for renewable energy source is biomass. Currently, about 5 x 10 19 kJ of energy is produced using biomass every year across the globe, which translates to roughly 10% of yearly global energy demand. It was forecasted that biomass could provide up to 150 x 10 19 kJ of energy globally by 2050. Other than energy production, biomass may also become more valuable as more eco-friendly chemicals are being extracted from biomass. To process large amounts of biomass, hydrothermal processing stands out as an attractive method. Compared to conventional pyrolysis and gasification methods which require dry biomass, hydrothermal methods can utilize wet biomass directly. This minimizes the cost of biomass pretreatment. Therefore, in this review, the current and future trends in hydrothermal processing of biomass for energy and chemical uses are discussed.