Phenol-rich bio-oil from pyrolysis of palm kernel shell and its isolated lignin

Abstract

Phenol and phenolic compounds are the important chemicals for several industries. To reduce the dependence on the petroleum-based production, lignocellulosic biomass becomes the promising resource. Palm kernel shell and its real isolated lignin were comparatively studied for the potential on the production of phenol and phenolic compounds via the pyrolysis process. Both samples were subjected to various chemical and thermal analyses to compare their chemical structures and thermal behavior. The pyrolysis process of palm kernel shell and its lignin was performed with a fixed-bed reactor to generate bio-oil with a high fraction of phenol and phenolic compounds. The extraction process could affect the structure of lignin and the pyrolysis behavior of the lignin. Pyrolysis experiments showed that the isolated lignin gave a higher yield of bio-oil than the palm kernel shell and about twice the total fraction of phenol and phenolic compounds. Phenol production from palm kernel shell was highest at a pyrolysis temperature of 500 °C, while yields of other phenolic compounds were highest at 400 °C. Including phenol, H-type phenolic compounds were the main product from both palm kernel shell and its isolated lignin. C-type phenolic compounds were found in significant quantities in the bio-oil from lignin. The total fraction of phenol and other phenolic compounds from the lignin bio-oil was up to 78 % and higher than that from the palm kernel shell bio-oil. • Isolated lignin of PKS was studied for phenol and phenolic production. • Highest production of phenol was from the pyrolysis of PKS at 500 °C. • Lignin generated more total phenol and phenolic compounds than PKS. • Lignin gave 78 % of phenol and phenolic compounds in bio-oil.