Brewer's spent grain pyrolysis kinetics and evolved gas analysis for the sustainable phenolic compounds and fatty acids recovery potential
Szymon Sobek, K. Zeng, Sebastian Werle, Robert Junga, Marcin Sajdak
Abstract
Within the presented paper, a thermochemical conversion via pyrolysis of spent grain from the local brewery (Alternatywa, Ruda Śląska, Poland) for phenolic compounds and fatty acids recovery is presented. Thermogravimetric pyrolysis was carried out at non-isothermal conditions (1, 2, and 4 K/min), under an inert N2 atmosphere. Deconvolution procedure for the kinetic modeling was implemented using own algorithm based on Gaussian function, using 3-stage kinetic mechanism, ascribed to the independent decomposition of the pseudo-components i.e., hemicellulose, cellulose, and bulk lignin-extractives. Released volatiles during pyrolysis was evaluated and recognized using gas chromatography-mass spectrometry and Fourier-transform infrared spectroscopy analysis, which confirmed the high content of fatty acids, phenolic compounds, and nitrogen compounds, with shares of 23.95%, 13.94%, and 25.10% respectively. Linkage of the desired product formations to the modeled kinetic stages of the BSG pyrolysis is a complex subject, and it is encouraged for future studies.