Thermodynamic analysis of fuel oil blended stock (FOBS) model compound, n-eicosane to hydrogen via oxidative cracking

Petrochemical refineries worldwide experience a common problem: the accumulation of fuel oil blended stock (FOBS). FOBS are any leftover oil blended with other similar unfinished oils, to make a final refined product. FOBS are not only of no value, but also it triggers storage and environmental concern. One way to overcome this is to upgrade FOBS into higher value-added product through oxidative cracking process. In this study, FOBS potential as a feed was investigated to produce hydrogen by utilizing n-eicosane as the model compound. A thermodynamic equilibrium analysis based on the total Gibbs energy minimization method was performed for n-eicosane cracking to hydrogen in the presence of oxygen. The effects of different reactants ratio, temperature and pressure, were studied. Equilibrium product compositions of n-eicosane at temperatures of 573 K-1273 K, pressure of 0-20 bar, n-eicosane/oxygen ratios (EO) (0.5:0.5, 0.7:0.3, 0.8:0.2, 0.9:0.1, 0.95:0.05) were analysed. It was discovered that the main product of oxidative cracking is hydrogen and methane. Furthermore, the results showed that the optimum reactant ratio for hydrogen and methane production is EO ratio 0.95:0.05. A network of reaction mechanisms has been postulated to explain the overall complex reactions happening in the process. (c) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

Petrochemical refineries worldwide face the common problem of accumulations of fuel oil blended stock (FOBS), which are of no value and pose storage and environmental concerns. This study investigates the potential of utilizing FOBS as a feed to produce hydrogen through oxidative cracking, and finds that hydrogen and methane are the main products, with an optimal reactant ratio of EO 0.95:0.05.