(743e) Development of Fe-Cu Oxygen Carriers for Solid Fuel Gasification and Hydrogen Production

Carbon dioxide emission from fossil energy conversion is a major contributor to the greenhouse effect. Therefore, development of processes to effectively convert fossil fuels with smaller carbon footprints is highly desirable. Chemical looping schemes, which include chemical looping combustion (CLC) and chemical looping gasification (CLG), have shown promise to convert carbonaceous fuels while capturing CO₂ efficiently. CLG, in particular, uses a solid metal oxide based oxygen carrier in a redox process to convert carbonaceous fuels into CO₂, hydrogen, and heat in separate reactors, avoiding the energy intensive product separation steps.

Currently, Fe based materials are oxygen carriers of choice for CLG processes since reduced iron oxides can effectively convert steam into hydrogen. The limitation of using Fe-based oxygen carriers is that they are relatively slow when converting carbonaceous fuels, especially those in solid forms. In order to address this challenge, we propose to incorporate a secondary metal oxide with oxygen uncoupling properties, e.g. CuO, to overcome the slow reactivity of Fe-based materials. A recent simulation study has shown that the addition of a small amount of CuO to a Fe₂O₃ oxygen carrier (9:1 molar ratio between Fe and Cu) can increase the efficiency of the process, resulting in higher H₂ production rates.

In the current study, a small amount of CuO based oxygen carrier is incorporated to a batch of Fe based material. TGA and fluidized bed experiments are conducted for chemical looping conversion of coal and methane. Significant increase in reactivity with coal char is observed with 5 w.t. % CuO addition. After the reaction, Fe-Cu spinel structure is not observed under XRD.