the sulfur-iodine and other tehrmochemical studies …€¦ · nea 3rd meeting on nuclear...
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NEA 3rd Meeting on Nuclear Production of Hydrogen, OARAI, Japan, 5-7 Oct. 2005 1
THE SULFUR-IODINE AND OTHER TEHRMOCHEMICAL STUDIES AT CEA
P. Anzieu, P. Carles, A. Le Duigou, F. Lemort, X. Vitart
CEA, France
NEA 3rd Meeting on Nuclear Production of Hydrogen, OARAI, Japan, 5-7 Oct. 2005 2
A CEA R&D StrategyConcentrate efforts on a scientific approach
• data acquisition (development of specific analytical devices)• modeling (physical models, flow-sheet analysis, systemic approach)
Develop expertise on thermochemical cycles assessmentsBenefit from collaboration with international programs
Basic Research
ThermodynamicsData acquisition
ModelingFlow-sheet analysisCorrosion studies
TechnologicalAssessmentsLaboratory loopsDemonstratorsTechnological
improvementsIndustrial viability
Collaboration with USA : GA, Sandia, Argonne, IdahoCollaboration with Europe : HYTECH programCollaboration with Japan : JAERI
Data acquisitionAnalytical devices
ModelingFlow-sheet
Analyticalmethods
Collaboration with USAArgonne
Collaboration with EuropeHYTECH program
NEA 3rd Meeting on Nuclear Production of Hydrogen, OARAI, Japan, 5-7 Oct. 2005 3
CEA’s program for nuclear hydrogen
Hydrogen massive production using nuclear heat
Thermochemical cycles HTE
Assessment Sulfur family Other cycles
Methodology
Flowsheet
Plant design
Reactor coupling
Sulfur-iodine Hybrid sulfur
Flowsheet
Process breakthroughs
Modeling
Materials
Materials for membranes
Flowsheet
Flowsheet
Technology
Modeling
Plant design
Economics
Reactor coupling
Economics
Bunsen: stoichiometry
H2SO4: high temperature part
HI: reactive distillation, membranes, catalysts
Hydrogen massive production using nuclear heat
Thermochemical cycles HTE
Assessment Sulfur family Other cycles
Methodology
Flowsheet
Plant design
Reactor coupling
Sulfur-iodine Hybrid sulfur
Flowsheet
Process breakthroughs
Modeling
Materials
Materials for membranes
Flowsheet
Flowsheet
Technology
Modeling
Plant design
Economics
Reactor coupling
Economics
Bunsen: stoichiometry
H2SO4: high temperature part
HI: reactive distillation, membranes, catalysts
Modeling Experiments Lower priority →
NEA 3rd Meeting on Nuclear Production of Hydrogen, OARAI, Japan, 5-7 Oct. 2005 4
Where are we today ?
• A R&D program was defined to get better and better
• 3 years work give an estimated efficiency of 35±5%• A lot of key points are identified
Effi
cien
cyes
timat
e
Time in year
25%
50%
75%
0%
35% ± 5
20042001
• But will they come more and more ?
NEA 3rd Meeting on Nuclear Production of Hydrogen, OARAI, Japan, 5-7 Oct. 2005 5
Main issues of Sulfur-Iodine cycleHI HI separationseparationHI HI decompositiondecomposition::•• catalystcatalyst ((reactivereactive distillation)distillation)•• incompleteincomplete reactionreactionHeatHeat demanddemand
SOSO33 decompositiondecomposition::•• catalystcatalyst•• couplingcoupling to to reactorreactor
450°C850°C H2SO4 Decomposition
H2
HIDecomposition
HIVaporization
O2
BunsenReaction
SO2
H2SO4Concentration
H20I2
SideSide reactionsreactionsStoichiometryStoichiometry
GeneralGeneral::Corrosion Corrosion IodineIodine losseslosses
NEA 3rd Meeting on Nuclear Production of Hydrogen, OARAI, Japan, 5-7 Oct. 2005 6
Bunsen section: objectives
xI2 + SO2 + (n+2)H2O ⇄ [H2SO4 + (n-m)H2O] + [2HI + (x-1)I2 + mH2O]
Bunsen Reaction
H2SO4(aq) phase HIx phase
Objectives:• Reduce excess of H2O and I2
while keeping phase separation
• Minimize side reactions
• Minimize heat losses
H2SO4 + 6 HI ⇄ S + 3 I2 + 4 H2OH2SO4 + 8 HI ⇄ H2S + 4I2 + 4H2O
NEA 3rd Meeting on Nuclear Production of Hydrogen, OARAI, Japan, 5-7 Oct. 2005 7
Bunsen section: experimental devices
Device Material Operating temperature Input chemicals
B0 Glass 30-60°C HI, H2SO4, I2, H2OB1 Glass 100-120°C (limit 1,5 bar) HI, H2SO4, I2, H2OB2 Ta 100-150°C I2, H2O, SO2
B3 Bunsen section of the I-NERI loop
B1
B0
B2
NEA 3rd Meeting on Nuclear Production of Hydrogen, OARAI, Japan, 5-7 Oct. 2005 8
0
0.2
0.4
0.6
0.8
1
200 210 220 230 240 250
Longueur d'onde (en nm)
Abs
orba
nce
H2SO4 = 0.5 I-
H2SO4 = 5 I-
H2SO4 = 50 I-
Bunsen section: analytical methods• Objectives:
– Composition of the phases– Control of parasite reactions
• Available methods (ex situ):– I: UV-visible measurements
after reduction of all ioded species– S: ICP-AES– H+: potentiometric titration
• Under development:– Voltamperometry (ex situ)– γ-absorptiometry– ATR probe– Anti-Stokes Raman diffusion
insi
tu
0
0.2
0.4
0.6
0.8
1
0 0.2 0.4 0.6 0.8 1
fraction molaire HI
fract
ion
mola
ire I 2 Brut
HIxH2SO4
CEA results
NEA 3rd Meeting on Nuclear Production of Hydrogen, OARAI, Japan, 5-7 Oct. 2005 9
Issues for the iodine section
Bubble Pressure of HI-H 2O Mixture
100°C
125°C
150°C
0
1
2
3
4
5
6
0 0.05 0.1 0.15 0.2 0.25
[HI]
P (b
ar)
Vapeur très pauvre en HI vapeur
Vapeur très riche en HI
[HI]azéotrope
• Exit of Bunsen section: HI/I2/H2O mixture (HIx)• HI/H2O(/I2) azeotrope: no simple separation• Slow and incomplete decomposition of HI
Azeotrope composition as a function of temperature for the binary mixture HI-H20 (models)
No experimental data available up to now in relevant conditions :flow-sheet calculations based on assumptions, extrapolations, best estimates
NEA 3rd Meeting on Nuclear Production of Hydrogen, OARAI, Japan, 5-7 Oct. 2005 10
Main options for the iodine section
H3PO4 I2
HI/(H2O/H3PO4)
HI
HI/H2/I2
H2O/H2
HI/I2/H2O
HI/I2/H2O
H2O
I2
H2O
I2
HI
H2O/H3PO4Distillate
Add third body
Recycle
HIx mixture from Bunsen section
H2
Concentrate HIx
Distillate
Separate H2
Reactivedistillation
Extractive distillation Electrodialysis Reactive distillation
Separate H2
Decompose HI
H2O
NEA 3rd Meeting on Nuclear Production of Hydrogen, OARAI, Japan, 5-7 Oct. 2005 11
HI section: experimental devicesObjective: HIx liquidObjective: HIx liquid--vapor equilibrium data in process vapor equilibrium data in process
Device Material Operating temperature Pressure Measurements
I1 Ta 100-300°C 1-100 bar Total pressure
I2 Glass up to 150°C 1,5 bar Partial pressures
I3 Ta 100-300°C 1-100 bar Partial pressures
conditionsconditions
Total Pressure of the ternary HI-H20-I2
0
200
400
600
800
1000
0 20 40 60 80 100 120
Temperature (°C)
Pres
sion
(mba
r)
LSRM
Littérature
I2
NEA 3rd Meeting on Nuclear Production of Hydrogen, OARAI, Japan, 5-7 Oct. 2005 12
Corrosion of materials• Bibliographic study• Preliminary screening tests:
– Bunsen section– HI section
• Study of associated mechanisms
0,1
1
10
100
1000
10000
Tantale Zirconium Hastelloy B3
Cor
rosi
on/ µ
m/y
aer
H2SO4
HI
mixte
0,1
1
10
100
1000
10000
Tantale Zirconium Hastelloy B3
Cor
rosi
on/ µ
m/y
aer
H2SO4
HI
mixte
1,E-10
1,E-09
1,E-08
1,E-07
1,E-06
1,E-05
1,E-04
1,E-03
1,E-02
1,E-01
1,E+00-1,2 -1 -0,8 -0,6 -0,4 -0,2 0 0,2
Potentiel / V/ESS
Den
sité
de
cour
ant /
A/c
m²
tantale
zirconium
Hastelloy B3
H 2SO 4 9 m ol/LT=95°CVb = 600 m V/h
Electrochemical tests in H2SO4
Tantalum, Tantalum, ZirconiumZirconium : stable passive layer
HastelloyHastelloy B3B3: anodic dissolution
NEA 3rd Meeting on Nuclear Production of Hydrogen, OARAI, Japan, 5-7 Oct. 2005 13
New devices for the study of corrosion• Bunsen section: from 2006
A new device for longer tests in more representative conditions
– Ta Reactor– Maximum temperature : 150°C150°C– Maximum pressure : 7 bars7 bars– Volume : 1.5 L1.5 L– Possible sampling of the
two liquid phases
• HI section: planned 2007
The CORBUN deviceThe CORBUN device
NEA 3rd Meeting on Nuclear Production of Hydrogen, OARAI, Japan, 5-7 Oct. 2005 14
A long route to viability: efficiency and cost optimization
Time
100%
0%
Theoretical efficiency
First approach Energetic efficiency More precise Flow-sheet
Exergetic efficiency
System & ComponentsOptimizationTarget efficiency
EvaluationR&D
Demonstration
• The challenges:– R&D activities with no iterative process
• flow-sheet assessment, heat distribution, materials, innovative concepts…– Answer questions about strategy for the hydrogen economy
• position vs. competitors (especially electrolysis), raw materials availability, safety, public acceptance, massive or dispersed production units…
NEA 3rd Meeting on Nuclear Production of Hydrogen, OARAI, Japan, 5-7 Oct. 2005 15
The UT_3 Cycle
Experimental Tests
Volatility Experimental evidence of high volatility of FeBr2 at 750°C
At 725°C/24h →→
At 750°C/24h Just above melting point of CaBr2→
→
CaBr2 ⇒ CaOCaBr2 ⇒ CaO Incomplete reactionParticle collapse
Hardened solidIncomplete reaction
Thermal cycling difficult
FeBr2 ⇒ Fe3O4 At 600°C/24h → Fe2O3 forms instead of Fe3O4→
At 700°C/24h
Incomplete reaction
Just above melting point of FeBr2� Fe2O3 forms instead of Fe3O4
The cycle is modified !
FeBr2 ⇒ Fe2O3
NEA 3rd Meeting on Nuclear Production of Hydrogen, OARAI, Japan, 5-7 Oct. 2005 16
The Hybrid Sulfur CycleElectrolysis
SO2 + 2 H2O + →H2 + H2SO4
O2/SO2 Separation
ReductionSO3-> SO2 + ½ O2
H2
O2
H2O
SO2 (2-10 bar)
H2SO4 35-50% (20-110°C, 2-10 bar)
H2O + SO3(600°C)
H2O
H2SO4 90-98% (350°C)
DecompositionH2SO4-> SO3 + H2O H2SO4 Concentration
O2 + SO2 (20-30 bar)
O2 + SO2 (900°C)
900°C
Electrolysis sectionSulfur thermocycle section
ElectrolysisSO2 + 2 H2O + →H2 + H2SO4
O2/SO2 Separation
ReductionSO3-> SO2 + ½ O2
H2
O2
H2O
SO2 (2-10 bar)
H2SO4 35-50% (20-110°C, 2-10 bar)
H2O + SO3(600°C)
H2O
H2SO4 90-98% (350°C)
DecompositionH2SO4-> SO3 + H2O H2SO4 Concentration
O2 + SO2 (20-30 bar)
O2 + SO2 (900°C)
900°C
Electrolysis section
ElectrolysisSO2 + 2 H2O + →H2 + H2SO4
O2/SO2 Separation
ReductionSO3-> SO2 + ½ O2
H2
O2
H2O
SO2 (2-10 bar)
H2SO4 35-50% (20-110°C, 2-10 bar)
H2O + SO3(600°C)
H2O
H2SO4 90-98% (350°C)
DecompositionH2SO4-> SO3 + H2O H2SO4 Concentration
O2 + SO2 (20-30 bar)
O2 + SO2 (900°C)
900°C
Electrolysis sectionSulfur thermocycle section
ElectrolysisSO2 + 2 H2O + →H2 + H2SO4
O2/SO2 Separation
ReductionSO3-> SO
ElectrolysisSO2 + 2 H2O + →H2 + H2SO4
O2/SO2 Separation
ReductionSO3-> SO2 + ½ O2
H2
O2
H2O
SO2 (2-10 bar)
H2SO4 35-50% (20-110°C, 2-10 bar)
H2O + SO3(600°C)
H2O
H2SO4 90-98% (350°C)
DecompositionH2SO4-> SO3 + H2O H2SO4 Concentration
O2 + SO2 (20-30 bar)
O2 + SO2 (900°C)
900°C
Electrolysis sectionSulfur thermocycle section
ElectrolysisSO2 + 2 H2O + →H2 + H2SO4
O2/SO2 Separation
ReductionSO3-> SO2 + ½ O2
H2
O2
H2O
SO2 (2-10 bar)
H2SO4 35-50% (20-110°C, 2-10 bar)
H2O + SO3(600°C)
H2O
H2SO4 90-98% (350°C)
DecompositionH2SO4-> SO3 + H2O H2SO4 Concentration
O2 + SO2 (20-30 bar)
O2 + SO2 (900°C)
900°C
Electrolysis section
• Main issues: Electrolysis Section– Membrane (SO2 permeation)– Cell over-voltage
NEA 3rd Meeting on Nuclear Production of Hydrogen, OARAI, Japan, 5-7 Oct. 2005 17
The Cerium Chloride Cycle
Ce-Cl
250°C
650°C
Cl2 + H2O
192 t/hCondenser
Cl295 t/h
H2O
24 t/h
H2O73 t/h
Cl2 + H2O
119 t/h
CeCl3660t/h
800°C
Evaporator
H2O
24 t/h
H2O24 t/h
+ X t/h
H2 + H2O +HCl
2.7 t/h + X t/h +287t/h
H2
2.7 t/h
CeO2461t/h
HCl
390 t/h
O2
21.4 t/hSeparating
device
liquidgazsolid
HCl295 t/h
SeparatingDeviceH2 + H2O
2.7 t/h + X t/h
UV
Evaporation
250°C
650°C
Cl2 + H2O
192 t/hCondenser
Cl295 t/h
H2O
24 t/h
H2O73 t/h
Cl2 + H2O
119 t/h
CeCl3660t/h
800°C
Evaporator
H2O
24 t/h
H2O24 t/h
+ X t/h
H2 + H2O +HCl
2.7 t/h + X t/h +287t/h
H2
2.7 t/h
CeO2461t/h
HCl
390 t/h
O2
21.4 t/hSeparating
device
liquidgazsolid
HCl295 t/h
SeparatingDeviceH2 + H2O
2.7 t/h + X t/h
UV
Evaporation
- Membranes were suppressed- High & rapid efficiency of reaction 2- Viability of reaction 3
Lab tests :
NEA 3rd Meeting on Nuclear Production of Hydrogen, OARAI, Japan, 5-7 Oct. 2005 18
UT_3 cycle
Gas-solid reactions:
MO + H2O + SO2 → MSO4 + H2 exothermal - low T°
MSO4 → MO + SO2 + ½ O2 endothermal - high T°M could be Fe (T > 730°C), Ni, Co, Mn
Sulfate cycles --------------------
Hybrid Sulfur cycle -----------------
SO2 + 2H2O → H2SO4 + 2H+ + 2e- Low T° Electrolysis <120°CH2SO4 → 4H2O + SO2 + ½ H2 High T° Decomposition
• Main advantage : max T° lower than for S-I
• A lot of unresolved difficulties + bromine toxicity
=> negative conclusion. We have given up this cycle
• Advantage : 2 reactions cycles
• Difficulties : transfer of solid, parasites reactions (formation of MS, H2S)
=> Tests underway
Cerium Chloride cycle ---------------
CaO + Br2 -> CaBr + 1/2 02 (500-600°C)CaBr2 + H20 -> CaO + 2 HBr (700-750°C)Fe3O4 + 8 Hbr -> 3 FeBr2 + 4 H20 + Br2 (200-300°C)3 FeBr2 + 4 H2O -> Fe3O4 + 6 HBr + H2 (550-650°C)
Evaluation of Other Thermochemical Cycles
• High H2 purity, anode voltage lower than for water electro., H2 produced at low T°
• Comparable to S-I : same H2SO4 section, No iodine section.
=> positive First-analysis : seriously competing with S-I cycle
• Chloride and materials well none• Medium toxicity
=> study underway
H2O + Cl2 → 2HCl + ½ O2 ~ 650 °C8HCl + 2 CeO2 → 2CeCl3 + Cl2 + 4 H2O ~ 100 °C2CeCl3 + 4H2O → 2CeO2 + 6HCl + H2 ~ 750 °C