THE SULFUR-IODINE AND OTHER TEHRMOCHEMICAL STUDIES …€¦ · NEA 3rd Meeting on Nuclear Production of Hydrogen, OARAI, Japan, 5-7 Oct. 2005 1 THE SULFUR-IODINE AND OTHER TEHRMOCHEMICAL

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


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


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 →


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 ?


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


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


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


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


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


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


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


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


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


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…


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


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


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)


O2 + SO2 (20-30 bar)

O2 + SO2 (900°C)

900°C

Electrolysis section


O2/SO2 Separation


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)


O2 + SO2 (20-30 bar)

O2 + SO2 (900°C)

900°C



O2/SO2 Separation

ReductionSO3-> SO


O2/SO2 Separation


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)


O2 + SO2 (20-30 bar)

O2 + SO2 (900°C)

900°C



O2/SO2 Separation


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)


O2 + SO2 (20-30 bar)

O2 + SO2 (900°C)

900°C

Electrolysis section

• Main issues: Electrolysis Section– Membrane (SO2 permeation)– Cell over-voltage


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 :


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

Documents

THE SULFUR-IODINE AND OTHER TEHRMOCHEMICAL STUDIES …€¦ · NEA 3rd Meeting on Nuclear Production of Hydrogen, OARAI, Japan, 5-7 Oct. 2005 1 THE SULFUR-IODINE AND OTHER TEHRMOCHEMICAL