Chemical Looping

We investigate chemical looping for the production of ultra-pure H2 via steam reforming or water gas shift reaction. By using an appropriate oxygen carrier (such as a metal/metal oxide pair) a chemical looping process temporally separates the oxidation and reduction products taking place during the methane reforming.  As the methane and air are not in contact, the resulting hydrogen product is unmixed with the carbon-containing product. Our focus is in the use of perovskite mixed metal oxides in a methane steam reforming chemical looping (CL) processes for the production of pure hydrogen with combined CO2 capture or syngas production.  Perovskites are expected to have a longer lifetime and similar activity compared to transition metal oxides, such as iron oxide, currently under study for CL processes.

Kinetic analysis of the steam iron process

 

 

   As the demand for hydrogen increases, the need for better hydrogen production systems grows.  This work looks at one such process that produces hydrogen via chemical looping, the steam-iron process.  This process traditionally utilises iron oxide as the oxygen carrier material (OCM).  The iron oxide is alternately reduced and oxidised using carbon monoxide as the reducing agent, and steam as the oxidising agent.  Water splitting occurs during the oxidation step and can produce pure hydrogen with suitably low CO levels (<50ppm) for use in fuel cells.  Air can also be introduced into the cycle to further oxidise the iron oxide by an exothermic reaction to provide heat to the system.  Other materials can be used in this system, such as perovskite types and supported iron oxides. This project is aiming to address the kinetics of this process, which are still not fully known.
Kinetics for the whole reactor bed are essential for reactor design purposes. Thus this work will investigate the kinetics along the length of a reactor bed made of either iron oxide or an iron-containing perovskite.  Additionally this project will study the thermodynamics of complete systems, with the aim to optimise energy requirements.