(182h) Solar Production of Hydrogen Using a Cadmium Based Thermochemical Cycle

While screening thermochemical cycles we determined that the
cadmium carbonate cycle has the potential of producing hydrogen at very high
efficiency using high temperature solar thermal energy.  The cycle consists of three chemical
reactions:

                                           Cd(s)
+ CO₂(g) + H₂O(l) => CdCO₃(s)            T
< 300^oC,

                                                    CdCO₃(s)
=> CdO(s) + CO₂(g)                     T
~ 500^oC,

                                                        CdO(s)
=> Cd(g) + ½ O₂(g)                       T
> 1400^oC.

The results are presented on an experimental program aimed
at accelerating the rate of the hydrogen production reaction.  A flowsheet is presented for the
overall process and the cost of hydrogen is estimated.