Executive Summary : | Although two-step thermochemical cycles such as the one based on Fe3O4¬ –FeO redox couple are intensively researched for solar hydrogen production, these suffer from a serious limitation of operating the two steps of the cyclic process at widely differing temperatures. In absence of an efficient heat recovery system a significant portion of the heat is lost due to heating and cooling at each cycle. In this work two pronged approach to circumvent the aforesaid limitations, are proposed: 1) limit to the most promising of two-step thermochemical processes and 2) Use of CH4 as a reducing aid that moderates the requirement of a high temperature for the reduction cycle of the active material. The gap in temperatures for the two of the redox cycling reactions will be minimised as much as possible. Moreover, during reduction process CH4 gets reformed, producing H2. The main step of H2 production is the cyclic oxidation of the active material requiring a lower temperature than the reduction step. The proposed process has a potential to offer significant efficiency gains over the conventional approach. |