(695e) Overcoming Lignin Agglomeration during Pyrolytic Sugar Production in a Fluidized Bed

Fast pyrolysis of acid infused biomass has enabled over 300% increase in sugars derived from the biomass carbohydrate fraction. Our research goal was to investigate the problem of lignin and carbohydrate interaction after acid infusion: promoting agglomeration and ultimately inhibiting volatilization of both the sugars and the phenolics. Increasing the production of sugars during fast pyrolysis is important because the sugars can be used for fermentation to biofuels and important chemicals currently derived from petroleum. Understanding the interactions is crucial to the advancement of thermochemical conversion technology utilizing acid pretreatment for enhanced sugar production. Alkali and alkaline earth metals (AAEM) found in biomass have negative impact on sugar yields during fast pyrolysis, catalyzing the formation of low molecular weight species. Inductively coupled plasma (ICP) determination of alkali and alkaline earth metals was performed on the biomass to determine the amount of acid infusion needed to neutralize the negative effects of the AAEM. The acid infused biomass samples were pyrolyzed using a 2 kg/h fluidized bed reactor. The biomass, the equivalency ratio which influences reactor operability, the amount of acid infusion, and neutralization steps, were varied followed by evaluation using various instrumentation. Thermogravimetric Analysis (TGA) was performed on each of the biomass samples for comparison to the starting biomass. Fourier transform infrared spectroscopy (FTIR) of the biomass was utilized for each of the pretreatment approaches. Specific wavelengths were selected that are attributed to either lignin or cellulose. Net integration of the intensities of the same absorption bands were compared between experimental parameters. Both hydrolysable and water soluble sugars quantities were established between the different pretreatments by high performance liquid chromatography (HPLC), while the relative molecular weight distribution of the phenolics was determined by gel permeation chromatography (GPC). Mass balances were obtained for each reactor run. With this approach we have accomplished uninterrupted fast pyrolysis of acid infused biomass with dramatically increased sugar production.