Pyrolysis of solid waste residues from Lemon Myrtle essential oils extraction for bio-oil production

Solid waste residues from the extraction of essential oils are projected to increase and need to be treated appropriately. Valorization of waste via pyrolysis can generate value-added products, such as chemicals and energy. The characterization of lemon myrtle residues (LMR) highlights their suitability for pyrolysis, with high volatile matter and low ash content. Thermogravimetric analysis/derivative thermogravimetric revealed the maximum pyrolytic degradation of LMR at 335 °C. The pyrolysis of LMR for bio-oil production was conducted in a fixed-bed reactor within a temperature range of 350-550 °C. Gas chromatography-mass spectrometry showed that the bio-oil contained abundant amounts of acetic acid, phenol, 3-methyl-1,2-cyclopentanedione, 1,2-benzenediol, guaiacol, 2-furanmethanol, and methyl dodecanoate. An increase in pyrolysis temperature led to a decrease in organic acid and ketones from 18.09% to 8.95% and 11.99% to 8.75%, respectively. In contrast, guaiacols and anhydrosugars increased from 24.23% to 30.05% and from 3.57% to 7.98%, respectively.