High purity hydrogen from coupled dry reforming and steam iron process with cobalt ferrites as oxygen carrier: Process improvement with the addition of NiAl 2O 4 catalyst

摘要

Graphical abstractDisplay OmittedHighlights?Cobalt ferrites doped with Al are feasible oxygen carriers for steam iron process.?NiAl2O4as a catalyst allows keeping the activity along SIP redox cycles.?High purity hydrogen can be obtained by working at 500°C in oxidation stages.AbstractCobalt ferrite with additive (alumina) has been proposed as oxygen carrier, to jointly carry out the dry reforming of a synthetic biogas, and the reduction stage of an oxide for producing hydrogen by “steam-iron” process. These reactions, as well as the associated reoxidation stage are performed within the same unit: a fixed bed reactor operating on a cyclic manner (redox) looking for the intensification at once of both, production and purification, of PEMFC quality hydrogen. This procedure is intended to be an alternative to traditional methods for producing hydrogen, which simultaneously consumes renewable raw materials and energy sources like biogas. Since catalytic activity of ferrites decays along cycles, the activity of the solid has been enhanced with the aid of small proportions of nickel aluminate with over-stoichiometric nickel oxide acting as catalyst. The addition of NiO/NiAl2O4has allowed maintaining the catalytic activity in the reduction steps, increasing the amount of reactive solid in the subsequent oxidation steps, and hence the amount of high purity hydrogen obtained per 100g of solid. In fact, the production of hydrogen for catalytic tests at Treduction=800°C reaches a value around 2.6g H2/100g of ferrite, when the non-catalytic counterpart gives only around 0.5g H2/100g of ferrite.]]>