(689c) The Effects of Heating Rate and Reaction Time On Hydrothermal Liquefaction of Microalgae

Hydrothermal liquefaction (HTL) is one of many methods for biomass conversion to biofuels or biofuel precursors. HTL avoids energy-intensive drying steps, and is therefore more energy efficient for biomass with very high moisture content, like microalgae. The effects of many different parameters (including biomass concentration, nominal reaction temperature, catalysis, and reaction time) on product yields for HTL of microalgae have been reported in the literature.  However, a majority of the reaction times reported in HTL literature have been defined to ignore the time necessary to reach the nominal reaction temperature. Furthermore, the heating times reported vary greatly, from several minutes to a few hours.

The time necessary to heat an HTL reaction mixture to the nominal reaction temperature is dependent on the heating rate. The heating rate of a reaction mixture has been observed to influence the product yields for HTL of woody biomass. Product yields for supercritical water gasification of glucose and cabbage are also influenced by heating rate. This presentation explores the influence of heating rate on the product yields for HTL of microalga Nannochloropsis sp. The influence of reaction time, including time necessary for the reaction mixture to reach the nominal reaction temperature, will also be discussed. These effects need to be considered during the development of an efficient HTL flow reaction process.