A computational analysis of operational parameters influencing coal gasification in a lab-scale drop tube gasifier

Abstract

This study uses a numerical simulation for coal gasification operation in a drop tube gasifier to investigate the effects of wall temperature and oxygen-to-coal (O/C) ratios on gasification. Coal gasification is an efficient approach to electricity generation, offering a cleaner alternative to conventional coal combustion methods. A 2D Computational Fluid Dynamics (CFD) model of the gasifier was employed to perform grid sensitivity analysis and subsequently compute the influences of varying wall temperatures (1000 K, 1250 K, and 1500 K) and O/C ratios (0.6, 0.8, 1, and 1.2) on the temperature profile, syngas composition, and velocity within the gasifier. Temperature profiling within the furnace defined a spectrum of maximum and minimum temperatures, with apex values recorded at 2100 K and lowest values at 1300 K for Cases 12 and 1, respectively. High O/C ratios favored the production of CO2 due to enhanced combustion reactions, whereas lower O/C ratios were conducive to higher yields of CO and H2, essential syngas components. Velocity profiles of particles within the gasifier increased with higher temperatures and O/C ratios, and the maximum velocity was 9 m/sec. In conclusion, this study offers valuable insights into optimizing operational parameters such as wall temperatures and O/C ratios to enhance the performance and efficiency of coal gasification processes in lab-scale gasifiers.