Hydrothermal Processing of Biomass

Hydrothermal processing is an inevitable thermochemical conversion process. Biomass is converted into biofuels or other value-added products. This generally includes heating wet slurries of biomass at high temperatures in order to produce an energy carrier. It is normally equivalent to the production of fossil fuels over billions of years. Hydrothermal processing is classified into three most important processes depending upon their operating temperatures. Temperature ranging between 180 and 250°C is named as hydrothermal carbonization, and between 250 and 375°C is termed as hydrothermal liquefaction. If the temperature range is above 375°C, it is termed hydrothermal gasification. The main advantage of hydrothermal processing technology is that it can be able to process wet feed, therefore avoiding the drying process of feed, which is usually employed for conventional processes, and it also reduces the cost involved. Even though it was experimented first in the year 1913 by Bergins, the research on hydrothermal processing boomed only around 2005 onwards. This chapter focuses on the overview of hydrothermal processing techniques and their recent research on all three classifications of hydrothermal processing technologies.