Characterization of bio-oils and bio-char obtained from the pyrolysis of a mixture of Lolium perenne, Festuca ovina, Festuca rubra and Poa pratensis grasses

In this work, the yield and chemical characterization of products obtained from the pyrolysis of a mixture of Lolium perenne, Festuca ovina, Festuca rubra and Poa pratensis grasses under an inert atmosphere at 600 degrees C with a heating rate of 50 degrees C/min was studied. Distribution of the products of pyrolysis grass sample was: moisture: 8 +/- 2%, total volatiles: 78 +/- 7%, char: 14 +/- 5%. Bio-oils were acidic and dark brown liquids and they were separated into oils, asphaltenes and asphaltols by solvent extraction procedures prior to gas chromatography-mass spectrometry (GC-MS) analyses. GC-MS results showed that the bio-oils contained complex mixtures of organic compounds, including acetic acid and a large variety of oxygenated and nitrogenated compounds such as phenols, pyridines, pyrazoles, imidazoles, amines, and ketones. SEM micrographs of the bio-chars indicated amorphous, porous and heterogeneous structure of the bio-char obtained from the grass sample. EDX analysis of the bio-char revealed that bio-char contained K, Ca, P and Mg elements.