Oxygen Carrier Development for Carbon Dioxide Capture from Fossil Fuels

The release of carbon dioxide (CO₂) from burning of fossil fuel has caused significant energy and environmental concerns. Carbon capture is a process to prevent the emissions of CO₂, a major source of greenhouse gases. Among the various carbon capture techniques, chemical looping combustion (CLC) has shown promise to be an efficient and effective method for CO₂capture.

The CLC process includes one reduction and one oxidation steps. In the reduction step, oxygen carrier reacts with fuel such as methane in the fuel reactor to reduce oxygen carrier, and produce a gaseous mixture of concentrated CO₂and water vapor. The oxidation step occurs in a separate air reactor where the reduced oxygen carrier and air react, regenerating oxygen carrier and producing heat. 

To achieve a high performance of CLC process, the selection of appropriate oxygen carriers is crucial. An oxygen carrier is usually composed of two parts: a metal oxide and a support. The metal oxide participates directly in CLC process, and the support can enhance the reduction-oxidation (redox) reactivity of the oxygen carrier by reducing the energy barrier for oxygen anion and electron conductions.

It has been suggested from the literature that barium cerium ferrite (BCF), calcium titanium ferrite (CTF) and lanthanum strontium ferrite (LSF) have good conductivities of oxygen anions and electrons. When they are used as the support part, we found that the redox activities of the ferrite base oxygen carriers are enhanced. The prepared catalyst samples are analyzed and observed by X-ray powder diffraction (XRD) and Scanning electron microscopy (SEM). From the obtained experimental data, CTF exhibited satisfactory stability, low cost, and good reactivity. Therefore, CTF can be used as a suitable oxygen carrier support in CLC process for CO₂capture and benefit environmental sustainability.

In this poster, I will present XRD patterns and SEM images of experimental samples to further illustrate the results.

This research project is advised and sponsored by Prof. Fanxing Li and Undergraduate Research Grant at NC State University.