Upgrading and dewatering of raw tropical peat by hydrothermal treatment

• Published in: Fuel (Guildford) 2010-03, Vol.89 (3), p.635-641
• Main Authors: Mursito, Anggoro Tri, Hirajima, Tsuyoshi, Sasaki, Keiko
• Format: Article
• Language: English
• Subjects: Applied sciences; Dewatering; Energy; Exact sciences and technology; Fuels; Hydrothermal treatment; Peat; Peat fuel; Tropical peat; Upgrading; Wood. Peat. Brown coal
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2009.07.004

In this study, hydrothermal upgrading and dewatering of raw tropical peat derived from Pontianak, West Kalimantan-Indonesia was evaluated at temperatures ranging from 150 to 380 °C, a maximum final pressure of 25.1 MPa and a residence time of 30 min. The moisture content of the raw peat was approximately 90 wt.%. Raw peat was hydrothermally upgraded without the addition of water in the laboratory scale. The yield of the solid products was between 53.0 and 99.7 wt.% and the effective calorific value of hydrothermally dewatered peat was between 17,290 and 29,209 kJ/kg following hydrothermal upgrading. In addition, the oxygen content in the solid product was varied from 38.4 to 15.6 wt.% after upgrading, while the carbon content from 55.2 to 77.8 wt.%. The hydrothermally upgraded peat fuel product also had an equilibrium moisture content of 2.3 wt.% and a maximum equilibrium moisture content of 17.6 wt.%. Upgraded peat is characteristically resistant to moisture adsorption at high humidity, which makes it promising for fuel based combustion. The change in the carbon-functional groups and their properties, as determined by FTIR and 13C NMR, are discussed in terms of the hydrothermal upgrading and dewatering process.