Fast pyrolysis of lignin-coated radiata pine

• A new wet coating method of biomass was developed.
• Fast pyrolysis of lignin-coated pine using a fluidized bed reactor was possible.
• As lignin is added, char, pyrolytic water yields and acids content were increased.
• Product distribution in bio-oil depended on the boundary layer thickness.

A new coating preparative method of the Pinus radiata feedstock was used to process a mixture of Acetocell lignin and sawdust prepared at different mass ratios of lignin to sawdust, 1:18 (LI20) and 1:7 (LI40) to overcome feeding issues into a fluidized bed pyrolysis reactor.The coated materials were structurally characterized by using spectrometric and microscopic techniques, which respectively confirmed the presence of saturated aliphatic and oxygenated side chains in the isolated lignin and the formation of a boundary layer around the woody biomass particles. The fast pyrolysis of the coated materials at 540 °C led to the decrease of both total liquid and organic yields and to the substantial increase of reactive water yield. Like yields, the addition of the technical lignin affected the product composition of fast pyrolysis bio-oil. These changes were both related to the oxygenated aliphatic nature of the lignin side-chains and to the thickness of the coating layer.This new preparation technique of the feedstock overcomes the technical barriers associated with the feeding of thermoset polymers into a bubbling fluidized bed reactor, without modifying its initial design; and enhanced the production of the phenolic rich fraction by controlling the thickness of the coating.