Production of H_2 and synthesis gas by chemical-looping reforming

摘要

Chemical-looping reforming is a novel process for partial oxidation of hydrocarbon fuel where oxygen is brought to the fuel by a solid oxygen carrier. Chemical-looping reforming has been examined in a laboratory reactor consisting of two interconnected fluidized beds. Particles of NiO and MgAl_2O_4 were used as bed material, oxygen carrier and reformer catalyst. Natural gas was used as fuel. The reactor temperature was 820-930 °C. There was a continuous circulation of oxygen-carrier particles between the fluidized-beds. In the fuel reactor the oxygen carrier was reduced by the fuel, which in turn was partially oxidized to H_2, CO, CO_2 and H_2O. In the air reactor the oxygen carrier was reoxidized with air. Formation of solid carbon was noticed for some cases. Adding 25 vol% steam to the natural gas reduced the carbon formation substantially. H_2 production by chemical-looping reforming with CO_2 capture has also been examined in a process study, where it was found that an overall efficiency of 81% including CO_2 sequestration is possible.