An Investigation of the Degradation of Lignin in Sub-Super Critical Water in a Continuous Flow Reactor

Lignin, after cellulose, is the most abundant organic compound on the planet and its conversion has significant potential as a source for the sustainable production of fuels and bulk chemicals. However, Lignin conversion into more meaningful products is a challenge due to the inherent complexity of lignin molecule. Despite many efforts in this field, degradation of lignin has not been entirely successful especially at large scale due to the plugging of catalysts with tars due to unwanted oligomerization reactions. To avoid this phenomenon, continuous flow systems appear to be a better option since they allow for reduced residence times, which may inhibit tar formation and because they are more likely to lead to viable industrial scale processes.

In this research, the degradation of lignin was investigated in a continuous flow reactor in super/sub-critical water at 25, 35 and 45 ml/min and 250, 300 and 320 . Solid, liquid, and gas phase products were collected and analyzed to determine the near optimum reaction conditions and performance results that can be expected from this type of system.