Swine manure/Crude glycerol co-liquefaction: Physical properties and chemical analysis of bio-oil product

The aim of this work was to investigate the principal structural and physico-chemical changes of bio-oils associated with liquefaction of swine manure with crude glycerol and its key fraction, free fatty acids. Bio-oils have been obtained from liquefaction processes at 340 °C. They were subjected to various physico-chemical characterization methods. FTIR data indicated a reduction in aliphatic structures and an increase in more oxidized and, probably, more polycondensed aromatic components resulting from the addition of crude glycerol to swine manure. GC–MS data indicated that the addition of crude glycerol facilitated the esterification reaction in sub-critical water to convert organic acids contained in bio-oil into various kinds of esters. The dynamic viscosity of bio-oil decreased dramatically by adding crude glycerol into the swine manure.