Experimental demonstration of pressurized chemical looping combustion in an internally circulating reactor for power production with integrated CO2 capture

This study presents an experimental demonstration of pressurized chemical looping combustion (CLC) in an internally circulating reactor (ICR). The ICR concept is a novel alternative to the conventional interconnected fluidized bed CLC configuration as it eliminates all cyclones, loop seals and solids transport lines, and it can be pressurized in a single pressure shell. Stable operation with high fuel conversion was established for about 40 h of operation at pressures up to 6 bar, achieving reasonable CO2 purity and capture efficiency (up to 97%). The solids circulation rate was found to increase with increasing the operating pressure at a constant fluidization velocity with no effect on CO2 capture and purity. The experimental campaign also examined the effects of solids inventory and fluidization velocities in the air and fuel reactors. The CO2 purity and capture efficiency were most sensitive to the solids inventory, whereas the solids circulation rate was most sensitive to the air reactor fluidization velocity and the solids inventory. A correlation for solids circulation rate was derived from the collected experimental data, thus providing a robust tool for designing an ICR system for pressurized operation. This correlation can assist in further scale-up and demonstration of the ICR concept in commercial scale.