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:
“A man had better starve at once than lose his innocence in the process of getting his bread.”
—Henry David Thoreau (1817–1862)
“To give an accurate description of what has never occurred is not merely the proper occupation of the historian, but the inalienable privilege of any man of parts and culture.”
—Oscar Wilde (1854–1900)