(739c) Iron Based Chemical Looping Gasification Using Gaseous Fuels

The chemical looping gasification (CLG) process circulates iron-based oxygen carrier particles through 3 reactors, namely reducer, oxidizer, and combustor, to perform reduction-oxidation reaction cycles for carbon dioxide capture and hydrogen production from various carbonaceous fuels such as natural gas and coal derived syngas. The countercurrent moving-bed operation of the reducer highlights the Ohio State University CLG technology. It ensures the full conversion of fuels while enhancing the extent of iron based oxygen carrier conversion. The high extent of iron based oxygen carrier conversion facilitates the generation of hydrogen from steam-iron reaction in the oxidizer. The combustor fully regenerates the oxygen carrier particles, which are then circulated back to the reducer via a riser. The CLG process can be configured to generate hydrogen, electricity or any combination thereof. It can also be incorporated into the Fischer-Tropsch process to enhance the efficiency and yield of coal to liquid fuels production. The process has been tested under a 25kW_th sub-pilot scale continuous operation for more than 300 hours with current efforts focused on the scale up demonstration of the 250 kW_th pilot CLG unit.

The design and operation of the 25 kW_th CLG sub-pilot unit will be the focus of this presentation. The design philosophy of the sub-pilot unit will be elucidated initially, with key emphasis on influence of the mode of operation. Multiple parametric operation studies for various gaseous fuels and system performance with regards to fuel conversions and hydrogen production will also be presented. Both multistage equilibrium modeling and dynamic reactive flow modeling have been conducted to compare the experimental results with the theoretical thermodynamic and kinetic conversions. Finally, the scale-up design and construction of the 250 kW_th pilot-scale unit will be updated.