Hydrocracking of Fischer‐Tropsch wax and its mixtures with heavy vacuum gas oil

In this study, Fischer‐Tropsch (F‐T) wax and bitumen‐derived hydrotreated heavy vacuum gas oil (HVGO) blends were co‐hydrocracked over a commercial catalyst in an autoclave reactor at a temperature of 360 °C and an initial hydrogen pressure of 4.2 MPa. 100 % F‐T wax and 100 % HVGO were hydrocracked under similar operating conditions as the reference feedstocks. The results revealed that the conversion of 360 °C+ materials decreased from 0.79 g/g (79 mass%) to 0.71 g/g (71 mass%) when the F‐T wax/HVGO blending ratio increased from 0/100 to 25/75 (g/g), then increased dramatically from 0.71 g/g (71 mass%) to almost 1 g/g (100 mass%) when the F‐T wax/HVGO blending ratio continued to increase to 100/0 (g/g). As the F‐T wax/HVGO blending ratio in the feed increased, the contents of cycloparaffins and aromatics decreased, whereas those of iso‐paraffins and n‐paraffins in the products increased. The research octane number and the motor octane number of the naphtha fraction also increased from 76 to 95 and from 76 to 82 when the F‐T wax/HVGO blending ratio increased from 0/100 to 100/0 (g/g), respectively. The product obtained from pure F‐T wax, which contained 0.8 g/g (80 mass%) of C5–C11 iso‐paraffins, was tested for diluent compatibility with Athabasca bitumen. The P‐value at 0.3 L/L (30 vol%) dilution was 2.11, close to that of 2.17 for natural gas condensate. Meanwhile, both the API gravity and viscosity met pipeline specifications, which indicates that the product hydrocracked from F‐T wax is a suitable diluent for bitumen.