Carbon Nanocatalysts for Aquathermolysis of Heavy Crude Oil: Insights into Thiophene Hydrodesulfurization

Abstract Various carbon nanomaterials, including carbon nanotubes (CNTs), ketjenblack (KB) carbon, and graphene nanoplatelets (GNPs), are investigated as catalysts for the hydrodesulfurization (HDS) reaction in the aquathermolysis of heavy crude oil. XRD and Raman spectroscopy are used to characterize the crystallinity and graphitization of these carbon samples. Their morphologies and structures are determined by TEM. Surface functional groups are analyzed by FTIR spectroscopy, and specific surface area and pore volume are studied by nitrogen adsorption–desorption. To evaluate the HDS activity of carbon nanocatalysts, thiophene is employed as a model compound because its ring structure is commonly present in asphaltene and resin components of heavy crude oil. The reactions are conducted under conditions similar to those of actual reservoir conditions of 120–180 °C and <3 MPa. Reaction parameters, namely, catalyst dosage, temperature, and reaction time, are studied to optimize the HDS performance. Results show that factors such as degree of graphitization and specific surface area play critical roles in the enhanced HDS activity of GNPs and KB compared with that of CNTs. This work opens up the opportunity for the implementation of carbon nanomaterials as sustainable metal‐free catalysts in the in situ upgrading and recovery of heavy crude oil.