Process Description
The thermochemical two-step water splitting process uses two redox steps. The steps of solar hydrogen production by iron baised two-step cycle are:
(1) M(II)Fe2(III)O4 → M(II)O + 2Fe(II)O + ½O2 (Reduction)
(2) M(II)O + 2Fe(II)O + H2O → M(II)Fe2(III)O4 + H2 (Oxidation)
Where M can by any number of metals often Fe itself, Co, Ni, Mn, Zn or mixtures thereof. The endothermic reduction step (1) is carried out at high temperatures greater than 1400 oC, though the "Hercynite cycle" is capable of temperatures as low as 1200 oC. The oxidative water splitting step (2) occurs at a lower ~1000 oC temperature which produces the original ferrite material in addition to hydrogen gas. The temperature level is realized by using a solar power tower and a set of heliostats to collect the solar thermal energy.
Read more about this topic: Iron Oxide Cycle
Famous quotes containing the words process and/or description:
“Science is a dynamic undertaking directed to lowering the degree of the empiricism involved in solving problems; or, if you prefer, science is a process of fabricating a web of interconnected concepts and conceptual schemes arising from experiments and observations and fruitful of further experiments and observations.”
—James Conant (1893–1978)
“The Sage of Toronto ... spent several decades marveling at the numerous freedoms created by a “global village” instantly and effortlessly accessible to all. Villages, unlike towns, have always been ruled by conformism, isolation, petty surveillance, boredom and repetitive malicious gossip about the same families. Which is a precise enough description of the global spectacle’s present vulgarity.”
—Guy Debord (b. 1931)