Impact of the heating mechanism on the yield and composition of bio-oil from pyrolysis of kraft lignin

The aim of this work is to differentiate between the yield and composition of bio-oils obtained from microwave and conventional pyrolysis of kraft lignin. Four different conditions were performed, microwave and conventional pyrolysis with and without mixing the raw material with a strong microwave receptor. The key findings of this work include that applying microwaves in pyrolysis applications leads to preserifing the structure of the obtained products, which consequently enhances the product selectivity. As a result, the liquid product from the pyrolysis of lignin contains 40% more chemicals, and 27% less water than that of the conventional pyrolysis. The impact of electromagnetic waves on the quantitative aspect is not considerable as the difference between the liquid yields from both techniques is slight. Increasing the heating rate and/or the residence time, particularly in conventional pyrolysis, makes secondary reactions play a vital role in decomposing and/or combining the obtained aromatic hydrocarbons. (C) 2016 Elsevier Ltd. All rights reserved.