Pyrolysis kinetic, thermodynamic and product analysis of different leguminous biomasses by Kissinger-Akahira-Sunose and pyrolysis-gas chromatography-mass spectrometry

Abstract

To ascertain the potential of various leguminous biomass such as L. leucocephala, C. proliferus, P. alba and S. sesban, both energetic and a source of high added value products, the pyrolytic behaviour was studied at different heating rates by using the analytical method of thermogravimetric (TG), isoconversional method of Kissinger-Akahira-Sunose (KAS), determination of some thermodynamic parameters and pyrolysis-gas chromatography- mass spectrometry (Py-GC/MS). It was concluded that biomass such as L. leucocephala or C. proliferus are more suitable for pyrolysis since less energy is required to degrade them, more evident in the final stages of degradation in which P. alba and S. sesban present very high activation energies calculated by KAS. All leguminous biomass produced volatile compounds with high phenol content at the peak of maximum degradation of hemicellulose, most of the heavy derivates are derived from lignin, such as ferulaldehyde or methoxyeugenol, because sufficient energy has not yet been provided to break down the structure. At this peak it can see some furans and saccharides in the case of C. proliferus since it has a higher C5 content in its composition. A wide range of compounds were detected at the peak of maximum degradation of cellulose, L. leucocephala ¡ and C. proliferus produce more short-chain compounds that give rise to bio-oils whereas, S. sesban and especially P. alba, in addition, produce a quantity of high added value of saccharides such as levoglucosan and D-allose (4.73% and 13.94%, respectively).