Chemical characterization of biomass pyrolysis oil facilitated by aerosolization and size separation

Abstract

Bio-oils are a promising renewable and carbon-neutral hydrocarbon material that can become a new energy source. Bio-oil mixtures have complex multi-component composition consisting of the pyrolysis products of cellulose, hemicellulose, and lignin of various molecular sizes with a range of highly oxygenated functional groups. Chemical characterization of bio-oil components is therefore necessary to inform the upgrading process of bio-oil and improve its commercial viability. We utilize aerosol technology to facilitate characterization of bio-oil components resulting in compositional differences specific to its volatility-separated fractions. We aerosolize bio-oil mixture, followed by size separation and collection of obtained particles using a cascade impactor, where the collected particles are exposed to sequentially reduced pressures at each of the impaction stages. We characterize components of the impactor separated bio-oil fractions using high-resolution mass spectrometry equipped with interchangeable electrospray ionization and dopant-assisted atmospheric pressure photoionization sources. Through examination of the detected chemical species in each of the separated fractions and assessment of their physiochemical properties, we identify a range of fuel-like aliphatic species with low O/C ratio and low viscosity in the most volatile fraction. The less volatile fractions contained progressively higher portions of more viscous species containing lignin and sugars moieties with characteristic high O/C values. We show that the impactor-based separation of bio-oil fractions facilitates comprehensive characterization of its components with varying fuel viability, capable of guiding upgrading processes.

Copyright © 2023 American Association for Aerosol Research

Graphical Abstract

EDITOR:

• Jim Smith

Authors’ contributions

E.H. and A.L designed the overall project framework and experiments. E.H. and C.P.W. conducted experiments. E.H. led data analysis with assistance from C.P.W., A.H., and A.D. J.J. and K.Q. assisted with data interpretation. E.H. and A.L. wrote the manuscript with contributions from all coauthors.

Disclosure statement

The authors declare that they have no conflict of interest.

Additional information

Funding

This work was supported by the National Science Foundation through Industry-University Cooperative Research Center for Bioanalytic Metrology under Grant No. IIP-1916691 and by industry partners.