|
The iron oxide cycle (Fe3O4/FeO) is the original two-step thermochemical cycle proposed for use for hydrogen production.〔(Project PD10 )〕 It is based on the reduction and subsequent oxidation of iron ions, particularly the reduction and oxidation from Fe3+ to Fe2+. The ferrites, or iron oxide, begins in the form of a spinel and depending on the reaction conditions, dopant metals and support material forms either Wüstites or different spinels. ==Process description== The thermochemical two-step water splitting process uses two redox steps. The steps of solar hydrogen production by iron based 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 geothermal heat from magma〔(Sentech 2008-Analysis of geothermally produced hydrogen on the big island of Hawaii )〕 or a solar power tower and a set of heliostats to collect the solar thermal energy. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Iron oxide cycle」の詳細全文を読む スポンサード リンク
|