Carbon Dioxide Reduction and Water Electrolysis System

摘要

An integrated system for oxygen recovery from carbon dioxide was investigated as a breadboard laboratory model of nominal 1/2-man capacity. System design for carbon dioxide reduction was based on alternate operation of two Bosch reactors with periodic cool down for removal of carbon and replenishment of catalyst. Experimental studies demonstrated attainment of the design objectives of a carbon-to-catalyst ratio above 20 and an overall carbon-packing density of 0.45 g/cu.cm. in the catalyst chamber. Degradation of Bosch reactor materials during extended operation was a problem that was not completely resolved. Experimental studies indicated that a regenerable solid-adsorbent based on combinations of silica gel and molecular sieve operating on alternate cycles of absorption and desorption can be used for efficient transfer of water vapor from the Bosch recycle gas to a water-vapor electrolysis cell. The original matrix-type water-vapor electrolysis unit with Pd-25Ag hydrogen diffusion cathodes did not perform satisfactorily and was replaced by a water-vapor electrolysis unit with phosphoric acid electrolyte for satisfactory evaluation of water-vapor transfer for the integrated system. (Author)