Transport Properties of CO₂ in Different Reactivity Coke Solution Loss Reaction Based on Stefan Flow Theory

In this paper, the influence of Stefan flow on different reactivity coke solution loss reaction (C_coke + CO₂ = 2CO) at different temperatures were analyzed and compared to deeply understand the mechanism of the coke solution loss reaction. Isothermal experiments of carbon dioxide gasification with Coke A (low reactivity), Coke B (medium reactivity), and Coke C (high reactivity), respectively, were carried out at 1100-1300 °C. After calculation, it is concluded that the external diffusion coefficients and the mass transfer coefficients with Stefan flow of three kinds of coke were decreased, and their minimum average deviations with and without Stefan flow were 44.57/43.27/43.23 and 42.57/39.47/39.15%, respectively. As the coke reactivity increased, the diffusion and mass transfer capacity of carbon dioxide with Stefan flow in the boundary layer decreased. The carbon dioxide concentration on the outer surface of three kinds of coke with Stefan flow was less than that without Stefan flow. The influence of Stefan flow on carbon dioxide concentration on the outer surface of coke was increased with the increase of coke reactivity. The area of carbon dioxide concentration region in the three kinds of coke declined after modification, and the deviations of the carbon dioxide concentration region area before and after modification of three kinds of coke ranged from 6.62 to 22.85%, 7.74 to 25.17%, and 8.62 to 26.74%. The influence of Stefan flow on the carbon dioxide concentration region increased as coke reactivity increased.