Hydrothermal Liquefaction of an Industrial Biomass Waste: Brewer’s Spent Grain (BSG)

Abstract

Brewer’s spent grain (BSG) is a source of lignocellulose that has a potential to be used for chemicals and fuels production, thereby reducing the reliance on fossil sources. There are relatively few investigations on using BSG; hence, the idea to valorise this agro-industrial waste is a great interest as BSG is available in large quantities throughout the year. Two modes of hydrothermal liquefaction (HTL) have been investigated using the raw BSG. The first mode used the raw BSG as received without pre-treatment while the second mode used the dried BSG with pure water. The conversion, water-soluble oil (WSO) yield and liquid product were measured for both modes. The liquid products were also analysed to determine the types and concentration of valuable products obtained. The characterisation of BSG reveals that the moisture content of the BSG is 74.7 wt.% while the FTIR spectra confirms the presence of lignocellulosic polymer in the BSG. The comparison between the two HTL modes indicates that the direct HTL provides better conversion, higher WSO yield and higher valuable products concentration. Therefore, it is concluded that BSG has a high potential to be converted into valuable products via direct HTL without pre-treatment. This opens a new opportunity for a sustainable alternative to waste valorization.

Anaerobic Digestion of Brewer’s Spent Grain With Biochar – Biogas Production Kinetics and Process Efficiency

“…The BSG spectra show the largest peaks at 3298, 2924, 2856, 1743, 1632, 1536, 1150, 1075, and 1123 cm -1 . Due to BSG being lignocellulose materials, most of the peaks are considered to come from the main polymers which are hemicellulose, cellulose, and lignin (Nasir et al, 2021). A signal at 3298 cm -1 is attributed to O-H and N-H bonds that come from hydroxyl, amine, and amide groups.…”