| The development of large, high-temperature solar furnaces makes processing at 1000-3000K practicable. In this study three examples of such kinds of processing which may have great practical importance were examined. They represent processes which can be used to: (1) Store solar energy--the splitting of water into hydrogen and oxygen. (2) Convert an undesirable waste product into valuable substances--the splitting of hydrogen sulfide into hydrogen and sulfur. (3) Recover an active metal from its oxide--the production of zinc from zinc oxide.; A two membrane process for producing hydrogen and oxygen from water was considered. A hydrogen-permeable membrane and an oxygen-permeable membrane were used to effect the separation.; For hydrogen sulfide, a process for producing hydrogen and sulfur, in which an effusion membrane was used to effect the separation, was evaluated.; Three methods of producing zinc from zinc oxide were considered: effusional separation, diffusional separation using an oxygen-permeable membrane, and high-temperature electrolysis.; For each process, I analyzed an appropriate, semi-idealized archetypal model. These analyses yielded thermodynamic efficiencies, showed the effects of process variables, revealed some merits and shortcomings, pinpointed potential problem areas, and suggested an imaginative technique which might be used to preserve membrane materials such as iridium and osmium in hostile environments. I conclude that the processes are intriguing possibilities, deserving further investigation. |
