Carbon Dioxide Reduction and Water-Vapor Electrolysis System

Experimental research on an integrated Bosch reactor and water-vapor electrolysis unit for oxygen recovery from carbon dioxide is described. A principal feature of the integration is the use of regenerable solid absorbent for periodic water-vapor transfer in a gravity-independent manner to avoid gas-liquid separation problems. The carbon dioxide reduction subsystem was based on batch-wise operation of two Bosch reactors to permit periodic shutdown for carbon removal. Experimental results are presented on operation of the Bosch reactor which include catalyst activation, recycle rate, recycle gas composition, reactor temperature, catalyst consumption, packing density of carbon and life of reactor materials during extended operation. Experimental data are presented on the solid-absorbent unit with silica gel and synthetic zeolites for removal of water vapor from the Bosch reaction and for water-vapor feed to an electrolysis unit. The feasibility of the sub-system integration was demonstrated for the laboratory model operating at the 1/2–1 man rate in a 50-hr run.