Thermodynamic and Kinetic Modeling of Orimulsion Gasification in an Entrained-Flow Reactor

The increasing generation of heavy petroleum residues has created significant environmental and energy-related challenges, while simultaneously providing an abundant potential feedstock for thermochemical energy conversion. Gasification offers a promising pathway for converting carbon-rich petroleum residues into a combustible synthesis gas (syngas) containing hydrogen (H₂), carbon monoxide (CO), and light hydrocarbons. In the present study, the gasification characteristics of heavy petroleum residues in an entrained-flow reactor were investigated using a combination of thermodynamic analysis and detailed chemical-kinetic modeling in CHEMKIN. An equilibrium-based approach was initially employed to establish a fundamental understanding of the pyrolysis and gasification behavior of the reference fuel. Subsequently, a kinetic model was developed in CHEMKIN to investigate the effects of key operating parameters on product-gas composition and energy content. Parametric analyses were performed to evaluate the influence of temperature, fuel moisture content, and gasifying-agent conditions on the formation of major gaseous products. The results demonstrate that operating temperature plays a critical role in determining the product distribution and significantly affects the formation of combustible species. Changes in fuel moisture content also modify the reaction environment and consequently influence the composition and energetic characteristics of the produced gas. The gasification stage was further investigated by examining the effects of different gasifying-agent conditions on the formation of H₂, CO, and CH₄. The results demonstrate a strong dependence of syngas composition on the operating conditions, reflecting the competition among pyrolysis, oxidation, water–gas, water–gas shift, methanation, and related gas-phase reactions. Based on the parametric analysis, an operating condition providing a favorable balance among hydrogen, carbon monoxide, and methane production was identified. The results demonstrate the capability of CHEMKIN-based kinetic modeling to provide insight into the governing chemical mechanisms of heavy petroleum residue conversion and to identify suitable operating conditions for syngas production.