Hydrogen from ethanol by steam iron process in fixed bed reactor

摘要

This research is devoted to the use of ethanot(i.e. bio-ethanol) in the combined production and purification of hydrogen by redox processes. The process has been studied in a single lab scale fixed bed reactor. Iron oxides, apart from their remarked redox behavior, exert an important catalytic role allowing the complete decomposition of ethanol at temperatures in the range from 625 to 750℃. The resulting gas stream (mainly H_2 and CO) reduces the solid to metallic iron. During a subsequent oxidation with steam, the solid can be regenerated to magnetite producing high purity hydrogen (suitable to be used in PEM fuel cells). Even though small amounts of coke are deposited during the reduction step, this is barely gasified by steam during the oxidation step (detection of CO_x in concentrations lower than 1 ppm). Influence of parameters like temperature, ethanol partial pressure and alternate cycles' effect has been studied in order to maximize the production of pure hydrogen.