Autothermal fast pyrolysis of waste biomass for wood adhesives

ABSTRACT

Biomass fast pyrolysis was performed in a bubbling fluidized bed reactor that incorporated two crucial innovations. A fractional condensation train provided dry bio-oils with only 1% of moisture and much reduced acidity. Autothermal pyrolysis with partial oxidation enhanced dry bio-oil quality while reducing the capital and operating costs by eliminating the need for external heating. Both endothermic pyrolysis with pure N2 and autothermal pyrolysis with oxidant fluidization gases were carried out at 500 degrees C. Dry bio-oils of birch wood, birch bark or hydrolysis lignin, from both endothermic and autothermal pyrolysis, could substitute up to 65 % of phenol in reacting with formaldehyde to produce wood adhesives that met the international standard specifications on mechanical strength and formaldehyde emissions. Therefore, autothermal pyrolysis did not harm the bio-oil quality for phenol substitution. Dry bio-oil from autothermal pyrolysis of kraft lignin was able to replace 80 % of the phenol.