Effectiveness and mobility of catalysts for gasification of bitumen coke

The compounds K₂CO₃, KCl, Na₂CO₃, CaCO₃, CaO, and MgO were tested as catalysts for steam gasification of coke from oil sands bitumen at atmospheric pressure and 600-800 °C. Catalysts were added to liquid vacuum residue prior to coke formation and directly to the coke solids. K₂CO₃ and Na₂CO₃ were most effective, giving nearly complete conversion at 800 °C in 30 min, regardless of whether they were added before or after coke formation. Ca and Mg compounds did not promote catalytic reactions, nor did they interact physically with the coke based on SEM and EDX analyses. KCl was effective, to a lower extent than K₂CO₃ and Na₂CO₃ only at higher temperatures (800 °C). The alkali metal compounds showed high mobility within the coke phase, which was consistent with their catalytic activities.