Performance of an iron based oxygen carrier in a 120 kWth chemical looping combustion pilot plant

Abstract

Chemical looping combustion is an unmixed combustion process with inherent separation of CO2. CLC technology has the capability to generate concentrated CO2 as further use for carbon capture and storage and thus reduce CO2 emissions. Since the use of cheap and non toxic oxygen carriers is favourable, iron is a potential candidate as active component.The performance of iron oxide impregnated on alumina (called Fe17) as oxygen carrier is investigated. Fe17 is tested in a 120kWth chemical looping combustion pilot plant at TU Wien. Various tests are carried out, the influence of active solid inventory, temperature, used gaseous fuel and oxygen carrier to fuel ratio are in the focus of the investigation. Post-experimental tests with thermogravimetric analysis, X-ray fluorescence analysis, particle size distribution and scanning electron microscope are used to characterize Fe17. The oxygen carrier shows attrition and a loss of iron. This leads to a drop of fuel conversion. The energy based fuel conversion is approx 40% to 60 %. For good fuel conversion, high inventories are needed in both reactors. Furthermore, high solid circulation rates and a high iron content on the particles show better fuel conversion.