taBle 11.1
Best two-, three-, and Four-step thermochemical Cycles
name/major
temperature
Compound
(°C)
details of Cycles
two-step Cycles
Tokyo Institute
1000
2MnFe 2 O 4 + 3Na 2 CO 3 + H 2 O → 2Na 2 MnFe 2 O 6 + 3CO 2 (g) + H 2 (g)
of Technology/
600
4Na 2 MnFe 2 O 6 + 6CO 2 (g) → 4MnFe 2 O 4 + 6Na 2 CO 3 + O 2 (g)
ferrite
Westinghouse/
850
2H 2 SO 4 (g) → 2SO 2 (g) + 2H 2 O(g) + O 2 (g)
sulfur
77
SO 2 (g) + 2H 2 O(a) → H2SO 4 (a) + H 2 (g)
Nickel ferrite
800
NiMnFe 4 O 6 + 2H 2 O → NiMnFe 4 O 8 + 2H 2 (g)
800
NiMnFe 4 O 8 → NiMnFe 4 O 6 + O 2 (g)
Hallett Air
800
2Cl 2 (g) + 2H 2 O(g) → 4HCl(g) + O 2 (g)
Products/chlorine
25
2HCl → Cl 2 (g) + H 2 (g)
three-step Cycles
Ispra Mark 13/
850
2H 2 SO 4 (g) → 2SO 2 (g) + 2H 2 O(g) + O 2 (g)
bromine/sulfur
77
2HBr(a) → Br 2 (a) + H 2 (g)
77
Br 2 (l) + SO 2 (g) + 2H 2 O(l) → 2HBr(g) + H 2 SO 4 (a)
Ispra Mark 8/
700
3MnCl 2 + 4H 2 O → Mn3O 4 + 6HCl + H 2 (g)
manganese/
900
3MnO 2 → Mn3O 4 + O 2 (g)
chlorine
100
4HCl + Mn3O 4 → 2MnCl 2 (a) + MnO 2 + 2H 2 O
Ispra/CO/Mn 3 O 4
977
6Mn 2 O 3 → 4Mn3O 4 + O 2 (g)
700
C(s) + H 2 O(g) → CO(g) + H 2 (g)
700
CO(g) + 2Mn3O 4 → C + 3Mn 2 O 3
Ispra Mark 3/V/
850
2Cl 2 (g) + 2H 2 O(g) → 4HCl(g) + O 2 (g)
chlorine
170
2VOCl 2 + 2HCl → 2VOCl 3 + H 2 (g)
200
2VOCl 3 → Cl 2 (g) + 2VOCl 2
Julich Center EOS/
800
2Fe 3 O 4 + 6FeSO 4 → 6Fe 2 O 3 + 6SO 2 + O 2 (g)
iron/sulfur
700
3FeO + H 2 O → Fe 3 O 4 + H 2 (g)
200
Fe 2 O 3 + SO 2 → FeO + FeSO 4
Gaz de France/
725
2K + 2KOH → 2K 2 O + H 2 (g)
KOH/K
825
2K 2 O → 2K + K 2 O 2
125
2K 2 O 2 + 2H 2 O → 4KOH + O 2 (g)
Aachen University
850
2Cl 2 (g) + 2H 2 O(g) → 4HCl(g) + O 2 (g)
Jülich 1972/Cr/Cl
170
2CrCl 2 + 2HCl → 2CrCl 3 + H 2 (g)
800
2CrCl 3 → 2CrCl 2 + Cl 2 (g)
US-Chlorine/Cu/Cl
850
2Cl 2 (g) + 2H 2 O(g) → 4HCl(g) + O 2 (g)
200
2CuCl + 2HCl → 2CuCl 2 + H 2 (g)
500
2CuCl 2 → 2CuCl + Cl 2 (g)
Ispra Mark 9/Fe/Cl
420
2FeCl 3 → Cl 2 (g) + 2FeCl 2
150
3Cl 2 (g) + 2Fe 3 O 4 + 12HCl → 6FeCl 3 + 6H 2 O + O 2 (g)
650
3FeCl 2 + 4H 2 O → Fe 3 O 4 + 6HCl + H 2 (g)
(Continued)
317
Water Dissociation Technologies for Hydrogen
Best two-, three-, and Four-step thermochemical Cycles
name/major
temperature
Compound
(°C)
details of Cycles
two-step Cycles
Tokyo Institute
1000
2MnFe 2 O 4 + 3Na 2 CO 3 + H 2 O → 2Na 2 MnFe 2 O 6 + 3CO 2 (g) + H 2 (g)
of Technology/
600
4Na 2 MnFe 2 O 6 + 6CO 2 (g) → 4MnFe 2 O 4 + 6Na 2 CO 3 + O 2 (g)
ferrite
Westinghouse/
850
2H 2 SO 4 (g) → 2SO 2 (g) + 2H 2 O(g) + O 2 (g)
sulfur
77
SO 2 (g) + 2H 2 O(a) → H2SO 4 (a) + H 2 (g)
Nickel ferrite
800
NiMnFe 4 O 6 + 2H 2 O → NiMnFe 4 O 8 + 2H 2 (g)
800
NiMnFe 4 O 8 → NiMnFe 4 O 6 + O 2 (g)
Hallett Air
800
2Cl 2 (g) + 2H 2 O(g) → 4HCl(g) + O 2 (g)
Products/chlorine
25
2HCl → Cl 2 (g) + H 2 (g)
three-step Cycles
Ispra Mark 13/
850
2H 2 SO 4 (g) → 2SO 2 (g) + 2H 2 O(g) + O 2 (g)
bromine/sulfur
77
2HBr(a) → Br 2 (a) + H 2 (g)
77
Br 2 (l) + SO 2 (g) + 2H 2 O(l) → 2HBr(g) + H 2 SO 4 (a)
Ispra Mark 8/
700
3MnCl 2 + 4H 2 O → Mn3O 4 + 6HCl + H 2 (g)
manganese/
900
3MnO 2 → Mn3O 4 + O 2 (g)
chlorine
100
4HCl + Mn3O 4 → 2MnCl 2 (a) + MnO 2 + 2H 2 O
Ispra/CO/Mn 3 O 4
977
6Mn 2 O 3 → 4Mn3O 4 + O 2 (g)
700
C(s) + H 2 O(g) → CO(g) + H 2 (g)
700
CO(g) + 2Mn3O 4 → C + 3Mn 2 O 3
Ispra Mark 3/V/
850
2Cl 2 (g) + 2H 2 O(g) → 4HCl(g) + O 2 (g)
chlorine
170
2VOCl 2 + 2HCl → 2VOCl 3 + H 2 (g)
200
2VOCl 3 → Cl 2 (g) + 2VOCl 2
Julich Center EOS/
800
2Fe 3 O 4 + 6FeSO 4 → 6Fe 2 O 3 + 6SO 2 + O 2 (g)
iron/sulfur
700
3FeO + H 2 O → Fe 3 O 4 + H 2 (g)
200
Fe 2 O 3 + SO 2 → FeO + FeSO 4
Gaz de France/
725
2K + 2KOH → 2K 2 O + H 2 (g)
KOH/K
825
2K 2 O → 2K + K 2 O 2
125
2K 2 O 2 + 2H 2 O → 4KOH + O 2 (g)
Aachen University
850
2Cl 2 (g) + 2H 2 O(g) → 4HCl(g) + O 2 (g)
Jülich 1972/Cr/Cl
170
2CrCl 2 + 2HCl → 2CrCl 3 + H 2 (g)
800
2CrCl 3 → 2CrCl 2 + Cl 2 (g)
US-Chlorine/Cu/Cl
850
2Cl 2 (g) + 2H 2 O(g) → 4HCl(g) + O 2 (g)
200
2CuCl + 2HCl → 2CuCl 2 + H 2 (g)
500
2CuCl 2 → 2CuCl + Cl 2 (g)
Ispra Mark 9/Fe/Cl
420
2FeCl 3 → Cl 2 (g) + 2FeCl 2
150
3Cl 2 (g) + 2Fe 3 O 4 + 12HCl → 6FeCl 3 + 6H 2 O + O 2 (g)
650
3FeCl 2 + 4H 2 O → Fe 3 O 4 + 6HCl + H 2 (g)
(Continued)
317
Water Dissociation Technologies for Hydrogen