硫化第一鉄を用いたH2Sの熱化学分解サイクル
H2SからのH2とS0の回収 (第1報)
1982 年 98 巻 1132 号 p. 523-528
詳細
1982 年 98 巻 1132 号 p. 523-528
This cycle consists of a combination of sulfurization of ferrous sulfide with hydrogen sulfide and thermal decomposition of the sulfurization product under normal or reduced pressure.
Three types of ferrous sulfide, thermal decomposition product of natural pyrite, natural pyrrhotite, and synthetic ferrous sulfide were examined.
Both sulfurization product and thermal decomposition product in every case were identified as ferrous sulfide by X-ray diffraction analysis. But the formation of higher sulfide such as pyrite in sulfurization is not always desirable, because it gives thermodynamically very small hydrogen concentration. A representation for the two step process in this research can therfore be given in the following equations, provided that FeS1+x and FeS1+x+y indicate nonstoichiometric composition of the sulfide.
FeS1+x+yH2S=FeS1+x+y+yH2 FeS1+x+y=FeS1+x+yS/yH2S=yH2+yS
The thermal decomposition product of natural pyrite showed the most favorable results for obtaining not only higher concentration of hydrogen but also larger amount of evolved hydrogen. This may be due to the porous solid structure caused by the volume contraction under thermal decomposition.
In the cyclic experiments, the hydrogen concentration at the sulfurization increased with an increase in the decomposition temperature, whereas the temperature determined as optimum for sulfurization was in the range from 500 to 650°C. The latter result can be considered as resulting from the interplay of the temperature dependence of the reaction rate and the equilibrium concentration of hydrogen.
