Performance characteristics of a miniaturised chemical looping steam reformer for hydrogen enrichment of fuels

A miniaturised chemical looping steam reformer (μ-CLSR) is being developed at the University of Newcastle (Australia) for onboard hydrogen enrichment of fuels in internal combustion engines. Experimental results from the first prototype highlighted an imbalance between the rates of redox reactions. A new configuration has been developed to resolve this shortcoming. The objective of this study is to examine the effectiveness of the new configuration in handling the imbalance between redox rates. Experiments were conducted on magnetite and wuestite metal oxides under methane and steam environments in the new configuration. Results indicate that if micro-reactors within the reformer are operated in parallel during the oxidation half cycle and in sequence during the reduction half cycle, the imbalance can be effectively managed. This combined with manifold switching of reacting gases at 48 s intervals enables metal oxides to achieve a 30% fractional conversion at 900 °C; resulting in a product gas stream with 96% H2 purity.

► The imbalance between rates of redox reactions creates operational issues in micro-scale manifold switching reactors.
►  The imbalance can be resolved if micro-reactors are operated in parallel during the oxidation half cycle.
► During the reduction half cycle micro-reactors must be operated in series.