Fuel Oil Blended Stock (FOBS) Valorisation: Thermodynamic Modelling of Pyrolysis to Hydrogen

Fuel oil blended stock (FOBS) is an accumulation of petroleum-based waste produced by the refinery industry and is often considered an undesirable byproduct. The issues concerning the abundance of FOBS have risen significantly over the past few decades due to continuous petrochemical operations. While various methods, such as recycling and energy recovery, have been implemented to manage FOBS residues, ongoing research is essential to develop more efficient alternatives and enhance existing solutions. A thorough understanding of thermodynamic parameters is crucial for optimizing these processes, as it enables early prediction of process outcomes, identification of potential hazards, and improved energy efficiency through reaction mechanism analysis. This study employs thermodynamic modelling using HSC Chemistry software, applying Gibbs free energy minimization for equilibrium calculations. Naphthalene (C10H8) was selected as the model reactant for pyrolysis to investigate syngas production. The effects of temperature (273 - 1,273 K) and pressure (1 - 50 bar) on equilibrium composition were examined by focusing on hydrogen (H2) gas as the primary product. The highest H2 yield, approximately 4.0 kmol was achieved at 1,273 K and 1 bar. The results showed that the production of H2 was enhanced by the formation CH4 as an intermediate in hydrogen generation. This novel thermodynamic evaluation of naphthalene that represents FOBS highlighted the potential of this waste material, potentially reinforcing the concept of waste-to-energy conversion. Keywords: fuel oil blended stock, hydrogen, thermodynamic analysis, FOBS, light hydroc