ABSTRACT
The increasing energy demand is building an impetus for extraction of liquid fuels from oil sands. This chapter describes the process of extraction of liquid transportation fuels from oil sands. The hydrocarbon mixture called bitumen is extracted from oil sands mainly via surface mining. For deep bituminous reserves, the steam-assisted gravity drainage (SAGD) technique is used. The bitumen is separated from sand, clay, or other minerals and water via a series of processes described in this chapter. It is upgraded by fractionation in atmospheric and vacuum distillation units. The long-chain carbon molecules are broken into smaller value-added molecules in hydrocracker and coker units, and the excess carbon is removed in the form of coke in the coker unit. The main product streams from the primary upgrading include naphtha, light gas oil (LGO), and heavy gas oil (HGO). The sulfur and nitrogen content present in the bitumen is transmitted to HGO and LGO. HGO contains 3.5–4.5 wt.% sulfur and 0.35–0.45 wt.% nitrogen, whereas LGO contains 2.0–2.5 wt.% sulfur and 0.12–0.17 wt.% nitrogen. These impurities need to be removed by the hydrotreating process before transferring the HGO and LGO for downstream refining in order to obtain the product specifications of liquid transportation fuel. Hydrotreating is a catalytic process, and a thorough understanding of the catalyst is required to develop a highly efficient catalyst. The better the catalytic performance, the better is liquid fuel quality and process economics. This chapter discusses about various hydrotreating NiMo catalysts supported on a variety of mesoporous materials including SBA15, M-SBA15 (M = Al, Ti, Zr); mesoporous ZrO2 and Al2O3; and mesoporous mixed metal oxide TiO2–Al2O3, ZrO2–Al2O3, and SnO2–Al2O3. The reaction mechanisms and the role of the catalyst are explained by a thorough characterization of catalysts using X-ray diffraction (XRD), N2 adsorption–desorption isotherms, Fourier transform infrared spectroscopy (FTIR), X-ray absorption near-edge structure (XANES), and high-resolution transmission electron microscopy (HRTEM). The hydrotreated LGO, HGO, 122and naphtha are blended to make synthetic crude, which is then processed in the existing refineries to obtain high-quality liquid fuels such as diesel, gasoline, kerosene, jet fuel, and petrochemicals. However, this industry faces many challenges, including bigger environmental footprint, tailing ponds, water usage, technological limitations, coke management, and land reclamation.
