Effect of water density and air pressure on partial oxidation of bitumen in supercritical water

• Published in: Fuel (Guildford) Vol. 95; pp. 347 - 351
• Main Authors: Sato, Takafumi, Trung, Phan Hieu, Tomita, Tomoyuki, Itoh, Naotsugu
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.05.2012; Elsevier
• Subjects: Applied sciences; Bitumen; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fuels; Heavy oil; Partial oxidation; Supercritical water; Water gas shift reaction; Water gas shift reaction; Partial oxidation; Supercritical water; Heavy oil; Bitumen; Methane; Coke; Water gas; Carbon dioxide; Density; Under pressure; High pressure; Low temperature
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2011.10.016

► Bitumen was partially oxidized in supercritical water for selective CO formation. ► The bitumen – supercritical water – air system consisted of two phases. ► The CO selectivity increased and the amount of total gas tended to decrease with increasing water/oil ratio. ► The increase in air pressure increased the amount of CO and CO2 and decreased the CO selectivity. ► Temperature, water/oil ratio and air pressure were important factors to govern partial oxidation of bitumen. Partial oxidation of bitumen was examined in supercritical water from 653 to 723K at a water/oil ratio from 0 to 3 and up to 5.1MPa of initial air pressure. The contents in the reactor were separated into water rich phase and oil rich phase. Most of oxygen was quickly consumed within 30min and the main gases produced were CO, CO2 and methane. The low temperature gave higher CO/(CO+CO2) ratio and suppressed coke formation. The amount of total gas tended to decrease and the ratio of CO/(CO+CO2) increased about two times by the increase in water/oil ratio from 0.5 to 3. The high water/oil ratio was preferred for selective partial oxidation to produce CO, which means that the effect of the enhancement of partial oxidation by supercritical water was probably larger than that of CO oxidation by water and water gas shift reaction. The increase in initial air pressure increased the amount of CO and CO2 and decreased the ratio of CO/(CO+CO2). The total oxidation route was enhanced under high air pressure.