Hydrogen production, oxygen separation and syngas oxy-combustion inside a water splitting membrane reactor

The present work provides numerical investigations of oxygen permeation, hydrogen generation through water splitting using an oxygen transport membrane and oxy-combustion of syngas. The work involves two models; one for hydrogen generation and oxygen permeation from water splitting, and the other for syngas reaction kinetics. Considering steam dissociation reaction and oxygen permeation process, the hydrogen generation model is developed from oxygen permeation model using user defined function (UDF) that enable the transfer of oxygen across the membrane. The codes were written in C++, then compiled and hooked to the ANSYS Fluent 15.0 software. The investigations revealed that, due to combustion, the syngas reactive flow results in higher oxygen permeation and hydrogen generation rates than the non-reactive case. Effects of various influential parameters such as fuel composition, membrane thickness, operating temperature, sweep gas flow rate and CO₂ circulation are investigated in the present study. It was realized that increase in sweep flow rate and inlet temperature results in enhanced oxygen permeation and hydrogen generation rates. Whereas, increase in CO/H₂ ratio, membrane thickness and CO₂ circulation reduces the amounts of hydrogen and oxygen generated.