Thermodynamic modeling and assessment of a combined coal gasification and alkaline water electrolysis system for hydrogen production

The performance of a clean energy system that combines the coal gasification and alkaline water electrolyzer concepts to produce hydrogen is evaluated through thermodynamic modeling and simulations. A parametric study is conducted to determine the effect of water ratio in coal slurry, gasifier temperature, effectiveness of carbon dioxide removal, and hydrogen recovery efficiency of the pressure swing adsorption unit on the system hydrogen production. The exergy efficiency and exergy destruction in each system component are also evaluated. The results reveal that the overall energy and exergy efficiencies of this system are ∼58% and ∼55%, respectively. The weight ratio of the hydrogen yielded to the coal fed to this system is ∼0.126. Although this system produces hydrogen from coal, the greenhouse gases emitted from this system are fairly low.