Upgrading of Heavy Oil by Hydrogenation through Partial Oxidation and Water-gas Shift Reaction in Supercritical Water

摘要

Partial oxidation of hydrocarbons including heavy oil in supercritical water forms CO and CO2, which undergoes the water-gas shift reaction to form active hydrogen and then hydrogenation of heavy oil proceeds. In the case of partial oxidation of hydrocarbons and bitumen in supercritical water, the selectivity for partial oxidative products such as CO increased with increasing water density. In the case of hydrogenation of heavy oil in supercritical water through the water-gas shift reaction, reverse water-gas shift reaction and decomposition of formic acid that is a reaction intermediate of the water-gas shift reaction, coke formation was suppressed compared to that in only supercritical water. The main factors for suppressing coke formation were as follows: high water density improving the reactivity of hydrogen source in the oil-rich phase that enhanced hydrogenation of asphal-tene core, direct injection of hydrogen source into the oil-rich phase increasing the concentration of active hydrogen in that phase, and coexisting gases with supercritical water facilitating the extraction of coke precursor from the oil-rich phase. The upgrading of heavy oil through a series of partial oxidation and hydrogenation reactions in supercritical water proceeded in the presence of catalyst and possible optimum conditions were proposed.