Magnetic separation for a continuous solar-two-step thermochemical cycle for solar hydrogen/CO production using ferrites

摘要

A novel solar-two-step thermochemical concept for continuous production of H(_2) or CO from solar energy and H(_2)O or CO(_2) using the redox pair MOFe(_2)O(_3)/MO as reactive particles is proposed and assessed. Here, an efficient continuous separation mechanism is devised by the use of an external magnetic field and the weak magnetization of MOFe(_2)O(_3) at the working temperatures. The mechanism is suitable for systems of ferrites with a Curie temperature in the range 500–800 (^{circ })C where water or CO(_2) decomposition occurs. One of the most promising candidates is the Fe(_3)O(_4)/FeO system. Pyromagnetic coefficients for Fe(_3)O(_4) were obtained experimentally. A simple magnetic trap was employed and the separation ratios Fe(_3)O(_4)/FeO were obtained. The results are encouraging and motivate the development of full-scale solar reactor prototypes.