Enhancing Gasoline Hydro-Desulfurization in a Fixed Bed Reactor: A Computational Fluid Dynamics (CFD) Study

Gasoline produced from fluid catalytic cracking (FCC) units contains substantial amounts of sulfur, which contributes to pollution. This study focuses on the hydro-desulfurization of gasoline in a fixed-bed reactor using computational fluid dynamics (CFD). The study provides a comprehensive analysis of reactor performance by investigating various parameters such as velocity, pressure, and temperature contours at different sections of the reactor. The visualization of these variations helps understand the hydro-desulfurization process in greater detail and aids in optimizing desulfurization technology. The simulations were conducted and validated results using operational data from the hydrogen refining unit of Abadan Oil Refining Company. The highest temperature was observed along the central line of the reactor, and the maximum pressure drop occurred in the catalytic section. The concentration of hydrogen sulfide (H2S), a product of the hydro-desulfurization reaction, increased by 15-fold and reached 0.008 kmol/m3 as it moves moved from the entrance to the outlet of the reactor. Additionally, the productivity of the reaction, as well as the molar concentration of H2S, increased with an increase in the feed mass flow rate. However, it should be noted that an increase in the feed temperature resulted in higher reaction yields, but it might also lead to the reduced thermal resistance of the catalyst, potentially affecting its effectiveness. Additionally, the concentration of gasoline and hydrogen decreased from the reactor inlet to the outlet, while the concentration of H2S increased.