Upgrading of heavy oil by dispersed biogenic magnetite catalysts

In situ catalytic upgrading of heavy oil offers significant cost savings and overcomes logistical challenges associated with the high viscosity, low API gravity and high molecular weight fractions of unconventional hydrocarbon resources. The THAI-CAPRI process (toe-to-heel air injection – catalytic upgrading process in situ) offers one such route to upgrading through the use of high surface area transition metal cracking catalysts surrounding the production well. Here, we describe the catalytic upgrading of heavy oil in a stirred batch reactor by a biogenic nanoscale magnetite (BnM; Fe₃O₄). A 97.8% decrease in viscosity relative to the feed oil was achieved and coking was lower compared to thermal cracking alone (6.9 wt% versus 10.2 wt%). The activity of this catalyst was further enhanced by a simple one-step addition of surface associated Pd to achieve loadings of 4.3, 7.1 and 9.5 wt% Pd. This led to significant decreases in viscosity of up to 99.4% for BnM loaded with 9.5 wt% Pd. An increment of 7.8° in API gravity with respect to the feed oil was achieved for 9.5 wt% Pd-BnM, compared with thermal cracking alone (5.3°). Whilst this level of upgrading was comparable to commercially available and previously tested catalysts, significant decreases in the coke content (3 wt% for 9.5 wt% Pd-BnM versus 10 wt% for thermal cracking) and associated increases in liquid content (∼90 wt% for 9.5 wt% Pd-BnM versus ∼79 wt% for thermal cracking) demonstrate the potential for the use of Pd-augmented biogenic magnetite as a catalyst in the THAI CAPRI process.