(700b) In situCatalytic Pyrolysis of Biomass Using Blast Furnace Slag As Catalyst

Catalytic pyrolysis of biomass using various acidic zeolite catalysts have shown promise of producing stable biomass pyrolysis oils that can be easily upgraded to fuels and biobased products. However, zeolite catalysts are relatively expensive and tend to produce low liquid yields, large fractions of gases and aqueous phase products and therefore there is a need to develop other catalysts that will improve liquid yields. Pine and pinyon juniper sawdust were pyrolyzed in a bench scale bubbling fluidized reactor using fine blast furnace slag, and acid treated blast furnace slag as the pyrolysis medium and nitrogen as fluidizing gas. The pyrolysis was conducted at 450-500 C and feed rate of 600-700 g/h for the pine sawdust and 100-200 g/h for the pinyon juniper biomass. The pyrolysis reaction showed an initial exotherm during the first 20 min and there was significant production of hydrogen for both feedstocks. The reaction became endothermic like most conventional pyrolysis reactions and hydrogen production decreased. The organic liquid yields ranged from 25 to 48 wt% depending on the run time, type of biomass and were higher than those reported for acidic zeolite catalysts. The char/coke yields ranged from 14 -18 wt%; the non-condensable gas yields ranged from 9 to 13 wt% and pyrolytic water yields ranged from 8 to 18 wt%. The oxygen content of the oils was 23-30 wt%, and the total acid number (TAN) was surprisingly low (23-26 mg KOH/g oil). The oils were less viscous than the sand pyrolysis oils. Thus the blast furnace slag appears to be a promising catalyst for the catalytic pyrolysis of biomass.