Supercritical water up-grading of heavy oils

In this issue, some recent R&Ds on heavy oil reforming by using supercritical water are introduced. There is a strong demand on up-grading heavy oils and bitumen in petroleum industries, since the quality of petroleum tends to be lower (heavier, and higher sulfur/metal contents). So far variety of up-grading methods have been studied and developed, including supercritical water treatment. Although there are some reports which suggests the superiority of supercritical water up-grading against steam cracking, the mechanism and kinetics of this reaction has not yet clarified and thus feasibility analyses of this process from energy, environmental, economic points of view have not sufficiently been conducted so far. Expected specific features of the supercritical process reported so far are 1) unique water reactions (both catalytic and non-catalytic) under the supercritical conditions, 2) control of reaction phase that affects the cracking reactions, 3) suppression of coke formation, and 4) in-situ extraction of heavier compounds during reactions. This paper describes those specific features by introducing previous research and some national projects in Japan. This issue summarizes the current status of R&D of SCW up-grading, with considering those points of view. First, properties and phase behavior of SCW systems are introduced. After summarizing the literatures of steam cracking of heavy oils, specific reactions of heavy oils in SCW are introduced, including the recent result of catalytic steam cracking, process development for SCW upgrading, including research on constructing materials, will be introduced.