Experimental and Numerical Evaluation of Hydrogen Production Potential through Gasification of Thermochemical Fluid-Stimulated Bitumen under CO₂-Rich Oxidants

Large-scale production of hydrogen (H₂) calls for the development of technology that abates environmental pollution in order to attain energy sustainability. Heat-generating chemicals, herein referred to as thermochemical fluids (TCFs), offer the advantage of steam generation for stimulating highly viscous oil, such as bitumen. The aim of this investigation is to explore H₂ production through gasification of TCF-stimulated bitumen under CO₂-rich oxidants (100_CO₂: 100% CO₂, 50_CO₂: mixture of 50% CO₂, and 50% O₂), compared with air (mixture of 21% O₂ and 79% N₂) and OxyFuel (100% O₂). Kinetic data from TCF reactions and those of thermogravimetric analysis of TCF-treated bitumen have been incorporated with relevant gasification reaction models to build a zero-dimensional steady-state thermodynamic model to simulate gasification using the Aspen HYSYS software. The TCF rate kinetics can be modeled using the second-order rate law with the activation energy E_TCF calculated to be 77.5 kJ/mol and the frequency factor A_TCF obtained to be 4.47 × 10⁶ (mol/dm³)⁻¹ (s^-1). Sensitivity studies were performed considering bitumen, oxidant, and TCF mass flow rates as input variables. The results generally revealed the potential to generate a significant fraction of H₂. It was also revealed that a higher H₂ fraction could be produced under 100% CO₂ oxidants compared with others, while higher CH₄ as well as CO gases could be generated under the OxyFuel oxidant. However, it was found that a higher CO₂ pollutant would be produced under 100% CO₂ gasification. Likewise, considering the sensitivity to oxidant feeds, it was found that the system could generate relatively low Na₂SO₄ pollutants with a higher fraction under OxyFuel as well as 50_CO₂ oxidant gas.