Chemical Looping Combustion using functional iron-based oxygen carrier particles

Chemical Looping Combustion (CLC) technologies utilize commonly metals/metal oxides as oxygen carrier, circulating between an air reactor and a fuel reactor. The oxygen carrier transfers oxygen from the air reactor to the fuel reactor to oxidize the fuel. After reduced by the fuel, the oxygen carrier is transferred to the air reactor to be oxidized to its original state under the effect of air. Therefore, the connection of the fuel reactor and air reactor makes up the CLC process for CO2 capture.

In the case of solid fuels, such as coal or biomass, the reaction pattern is more complex. In the fuel reactor the char should be firstly gasified by gasification agents such as steam or carbon dioxide, and then the gasification products react with the oxygen carriers. The presence of oxygen carrier particles in the fuel reactor could accelerate char gasification rate, since the gasification products surrounding the oxygen carrier particles are consumed. However, this enhancing effect is not sufficient, especially for coal with a low reactivity. In order to minimize the char elutriation and loss to the air reactor, to accelerate char gasification rate in the fuel reactor is a significant issue.

The basic objectives of this proposed research is to obtain high coal conversion, high gas conversion and high CO2 capture during the CLC process of coal with the functional iron-based oxygen carrier particles. In this research, the cheap materials will be used to develop some novel oxygen carrier particles with high reactivity. A commercial strategy for the functional iron-based oxygen carrier particles with catalytic reactivity to accelerate coal gasification will be developed. The catalytic mechanism will be investigated. Further, the pilot scale CLC facility of Hamburg University of Technology of Germany will be used to carry out the investigation during the continuous coal-fueled CLC experiments.