A numerical study on gasification of a single-pore char particle in supercritical water

Gasification models of a char particle based on the true porous structure are essential for the accurate simulation of gasifiers, and pore-scale study might provide important information for the development of the porous char particle gasification models. In this paper, a numerical study was conducted on the gasification of a single-pore char particle in supercritical water, and the emphasis was put on the gasification process inside the pore with the effects of surrounding fluid, pore structure and pore position considered. The results showed that the gasification in a pore was quite affected by pore diffusion. The increase in temperature and particle Reynolds number promoted the gasification in the pore, and convection mainly enhanced the heat transfer but had limited promotion on mass transfer in kinetically controlled regime. Increasing pore length and decreasing pore diameter caused the increase in diffusion resistance and the former had more obvious effects. However, the decreased pore diameter increased the specific surface area and benefited the whole char conversion. The pore position affected the species distribution inside the pore for non-diffusive gasification, and the impact was limited in kinetically controlled regime. Finally, study in this work will be further extended to the gasification of the porous char particle.