Simulation and Optimization of Coal Gasification in a Moving-bed Reactor to Produce Synthesis Gas Suitable for Methanol Production Unit

Abstract

This paper presents process simulation and optimization of coal gasification process in a moving-bed reactor using Pittsburgh No. 8 coal as feed. The system of differential equations for the mass and energy balances was solved using 4th-order Runge-Kutta method and optimized by non-dominated sorting genetic algorithm-II (NSGA-II) meth-od. The simulation was used to predict solid and gas temperature profile and gas compo-sition along the reactor. The simulation results were compared successfully with experi-mental data relevant to Westfield plant in Scotland. In addition, the effect of operating parameters such as coal-to-oxygen molar ratio, steam-to-oxygen molar ratio, inlet gas temperature, reactor pressure, and oxygen mole fraction in inlet air on amount of synthe-sis gas (syngas) production, hydrogen to carbon monoxide molar ratio (HCMR) in pro-duced syngas, and coal conversion was investigated. Finally, the reactor performance was optimized to produce the highest syngas production with a HCMR of two using NSGA-II method.

Keywords

• moving-bed reactor
• coal gasification
• simulation
• optimization
• methanol
• synthesis gas