Upgrading of oil sand bitumen over an iron oxide catalyst using sub- and super-critical water

•Upgrading of bitumen was carried out under sub- and super-critical conditions using an FeOx-based catalyst.•Heavy oil was effectively decomposed over the FeOx-based catalyst using sub-critical water.•Decomposition of bitumen over the catalyst proceeded efficiently at 19.0 MPa and above 673 K.•The catalyst after removal of coke deposited by calcination in air showed almost the same activity as the fresh catalyst.

Upgrading of oil sand bitumen was examined using a catalyst consisting of CeO2–ZrO2–Al2O3–FeOX and sub- and super-critical water in two reactor types: batch-type and fixed-bed flow-type. Bitumen diluted with benzene was used as a feedstock, and the effects of reaction pressure and temperature on product yield were investigated. Under conditions of high pressure (approximately 19 MPa), catalytic decomposition of bitumen proceeded effectively over the FeOX-based catalyst, with the yield of lighter components such as gas oil and vacuum gas oil (VGO) reaching 70 mol%-C at a reaction temperature of 693 K. Moreover, because coke formation on the catalyst was suppressed (less than 10 mol%-C under optimized reaction pressure and temperature), the FeOX-based catalyst showed excellent durability and reusability for catalytic decomposition of bitumen.

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