(13e) Pilot Scale Production of Biocrude Oils From Biomass: Effect of Feedstock

The production of high quality biocrude oils was performed in a direct step via fractional catalytic pyrolysis with recycling of the non-condensable gases. For the purpose of investigating the effect of biomass type, various feedstocks including hybrid polar, pine, corn stover, switchgrass and pine bark were pyrolyzed with HZSM-5 zeolite in a 10 cm bubbling fluidized bed reactor at 475 ^oC. TGA-FTIR   studies were also conducted in support of the work. The product distribution and the quality of the biocrude oils were feedstock dependent. The overall liquid yields were 30 - 44.5 wt.%  and char/coke  ranged between 15 wt% and 25 wt%. Generally, the oils had relatively higher pH (3.25-5.05), lower viscosity (23-95 cSt) and lesser density (1.06-1.14 g/cm³) compared to the non-catalytic experiments. The oils were also analyzed for elemental composition (CHNSO) and higher heating value. The gas analysis showed that the rejection of oxygen in the form of CO was predominant in the woody biomass compared to the herbaceous feedstocks. The average CO/CO₂ ratio for hybrid poplar was 2.0 and that of switchgrass was 1.1. ¹³C-NMR and FT-IR analysis of the biocrude oils showed cracking of carbohydrate decomposition products such as levoglucosan and acetic acids. The concentration of phenols and aromatic hydrocarbons in the biocrude oils were dependent on the feedstock used.