Simulation of Synthesis Gas Production from Steam Oxygen Gasification of Colombian Coal Using Aspen Plus®

Abstract

A steady state simulation of syngas production from a Steam Oxygen Gasification process using commercial technologies was performed using Aspen Plus^®. For the simulation, the average proximate and ultimate compositions of bituminous coal obtained from the Colombian Andean region were employed. The simulation was applied to conduct sensitivity analyses in the O₂ to coal mass ratio, coal slurry concentration, WGS operating temperature and WGS steam to dry gas molar ratio (SDG) over the key parameters: syngas molar composition, overall CO conversion in the WGS reactors, H₂ rich-syngas lower heating value (LHV) and thermal efficiency. The achieved information allows the selection of critical operating conditions leading to improve system efficiency and environmental performance. The results indicate that the oxygen to carbon ratio is a key variable as it affects significantly both the LHV and thermal efficiency. Nevertheless, the process becomes almost insensitive to SDG values higher than 2. Finally, a thermal efficiency of 62.6% can be reached. This result corresponds to a slurry solid concentration of 0.65, a WGS process SDG of 0.59, and a LTS reactor operating temperature of 473 K. With these fixed variables, a syngas with H₂ molar composition of 92.2% and LHV of 12 MJ Nm⁻³ was attained.