Production of hydrogen by steam oxidation of calcium ferrite reduced with various coals

Abstract Production of H 2 by steam oxidation was demonstrated with calcium ferrite (CaFe 2 O 4 ) after coal gasification to produce CO with several types of coals. All coal types reacted with CaFe 2 O 4 to produce CO. The reduced CaFe 2 O 4 after the reaction with coal can also be oxidized with steam at 800  ° C while producing of H 2 . Sub-bituminous coal and lignite coal had better reactivity with CaFe 2 O 4 than the bituminous coal. A ten-cycle test conducted with Wyodak coal/CaFe 2 O 4 at 800  ° C showed stable production of H 2 during oxidation with steam. A 25-cycle steam oxidation test conducted after reduction of CaFe 2 O 4 with lignite coal also showed a very stable performance. Steam oxidation is sufficient for maintaining the cyclic reactions. A larger scale (2 kg batch) production of CaFe 2 O 4 by wet granulation-tumbling method was successful. Steam oxidation was demonstrated with the large-scale batch of CaFe 2 O 4 after reduction with Wyodak coal.