The effect of process variables on pyrolysis in a freefall reactor

The focus of this work is to test variables of fast pyrolysis conditions in a free fall reactor in order to better understand their impact on pyrolysis products, specifically optimization of biooil yields. In the first study, a design of experiments was performed and products were analyzed to evaluate the effects of temperature, sweep gas flow rates, and particle heating time, on bio-oil yields. This study proved particle heating time to be a very important variable effecting bio-oil yields, and that a heating time of greater than the traditionally assumed two seconds must be achieved in order to optimize yields. The second study focused on the effects of extended solids heating time on bio-oil yields. Six experiments were conducted to test two collection methods, under both heated and cooled conditions, in order to better understand phenomena occurring after the solid particles have passed through the reactor. The products were analyzed, and results concluded that particles are not completely volatilized after two second in the heating portion of the reactor. Analysis also proved that vapors are still produced over 40 seconds after the particles have left the heating portion of the reactor. Overall, these experiments have concluded that the some often neglected variables may have a larger impact on bio-oil yields than previously believed.