La sub 2 (SO Sub 4 ) sub 3 Thermochemical Cycle for Hydrogen Production

摘要

The rate of decomposition of La sub 2 (SO sub 4 ) sub 3 is very high at temperatures >1425 exp 0 K, high enough to be useful for a thermochemical cycle. At progressively lower temperatures the rate falls rapidly and is too slow for consideration below 1350 exp 0 K. The results are shown in graphic form. An analysis of these results was made to determine the controlling step in the decomposition. The data were fitted to the model for small particles with gas film diffusion being the controlling step. In previous studies of sulfate decomposition up to about 1200 exp 0 K, the major component in the product was found to be SO sub 3 with only small amounts of SO sub 2 . At the higher temperatures of the present experiments some additional decomposition of SO sub 3 and a larger fraction of SO sub 2 was expected, and indeed the fraction of SO sub 2 did increase considerably as the temperature was increased. Even though the concentration of SO sub 2 increases much faster than SO sub 3 LANL evaluations indicate that the composition is not at equilibrium, and a catalyst for SO sub 3 decomposition may be helpful. (ERA citation 07:003503)