2008 DOE Hydrogen Program ReviewSulfur-Iodine Thermochemical Cycle

Paul PickardSandia National Labs

June 12, 2008

Project PD25This presentation does not contain any proprietary or confidential information

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Sulfur-Iodine Thermochemical Cycle Project Overview

• Start - 4/2006• Finish - 4/2009 • ~ 80% complete

• Materials – high temperature, corrosive environments

• Process chemistry, catalysts, diagnostics

• Reactor-process coupling

• Funding – FY06- 5.5 M$– FY07 - 4.3 M$– FY08 - 2.9 M$– French CEA – in kind

Timeline

• INERI Project with CEA• Process – CEA, SNL, General

Atomics • Supporting Technologies –

INL, UNLV

Budget

Barriers

Partners

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Sulfur-Iodine Thermochemical CycleObjectives

• Evaluate the potential of the Sulfur-Iodine cycle for hydrogen production using nuclear energy– DOE/NHI - CEA INERI Project (CEA, SNL, General Atomics)– Sulfur cycles – potential for high efficiency, relative development level – Approach - construct, operate an Integrated Lab Scale (ILS)

experiment to investigate the key technical issues – Provide basis for nuclear hydrogen technology decisions

Phase 2 -- (Integrated Lab Scale Experiment - ILS)FY06 - Develop the 3 major reaction sections for S-I at 3 locations FY07 - Integrate 3 sections at General Atomics experiment site FY08 - Conduct integrated lab scale, closed loop experiments

Phase 1 (Cycle Evaluation) FY03 – 05 - Process chemistry options, flowsheets, materials, small scale

experiments

x I2 + SO2 + 2 H2O H2SO4 +2 HIx

DISTILLATION

H2SO4

H2Ox I2

H2O

HIx

HI

H2SO4 H2O + SO2 + 1/2O2

2 HI H2 + I2

H2

H2O

SO2

T °C

200

400

800

600

1000

0

Tem

pera

ture

(C)

NHI Sulfur Based Thermochemical CyclesSulfur-Iodine

Sulfur Iodine(1) H2SO4 → H2O + SO2 + 1/2O2(2) 2HI → I2 + H2(3) 2H2O + SO2 + I2 → H2SO4 + 2HI

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Sulfur-Iodine Integrated Lab Scale Experiment ILS Approach

Conduct ILS Experiments

Develop, test 3 reaction sections

FY2006• HI decomposition -extractive distillation (Gen Atomics)

• H2SO4 – SiC bayonet decomposer (SNL)

• Counter-current Bunsen reactor (CEA)

FY2007• H2SO4 section

operational FY07 • CEA Bunsen section

installed 6/2007• 3 sections connected

with interface unit, prelim testing

Integrate 3 sections at GA

FY2008 • Stand alone section tests completed

• Initial integration (Section 1 & 2) and first full sequence H2 test conducted

• FY08 integrated exps

ILS Exp Improvements

FY2009 • Performance

improvement mods• Longer term exps• Provide basis for

performance, and cost projections

• Pilot scale design

0

50

100

150

200

250

0:00:00 1:12:00 2:24:00 3:36:00 4:48:00 6:00:00 7:12:00 8:24:00Elapsed time (hrs)

Tem

pera

ture

(deg

C)

TT_204TT_206TT_213ATT_213BTT_213CTT_213DTT_213ETT_213FTT_213G

12 13Time of Day (hr:min)

0

25

50

75

100

125

150

175

200

Sul

fur D

ioxi

de F

low

Rat

e (li

ters

/hr)

12:10 12:20 12:30 12:40 12:50

3 bar 2 bar

1 bar

6

• Interface skid - allows independent operation of each section, facilitates startup, shutdown

• Lexan enclosures, separate ventilation system for each section • Initial integrated operations underway - March 2008

A = H2SO4 BufferB = Water BufferC = Vent ScrubberD = HIx Buffer

1.00 mol/hr SO2 E = Water Buffer2.79 2.21 mol/hr H2O F = Iodine Buffermol/hr 0.50 mol/hr O2H2O 0.00493 mol/hr H2SO4

mol/hr SO20.50 mol/hr O2 1 mol/hr H2SO4

4 mol/hr H2O

2 mol/hr HI10 mol/hr H2O

8 mol/hr I2

1mol/hr H2O

11 mol/hr H2O 9 mol/hr I2 mol/hr HI

1 mol/hr H222.41 lit/hr H2

Section 1Bunsen Reaction

Section 2Sulfuric Acid

Decomposition

Section 3HI

Decomposition

AInterface Buffer

SkidB

D E F

C

113

108

201 203101A 207

105

301 322 309 + 316113 112

310A

319B

101A

Sulfur-Iodine ILS Experiment Status

S-I Integrated Lab Scale Experiment at GA Site

H2SO4 Decomposition

Bunsen Reactor

HI Decomposition

Interface Unit

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Technical Accomplishments/ ProgressOverview

• HI decomposition (GA) – First hydrogen production experiment using CEA Bunsen section feed material ~50

liters/hr - April 2008 – Iodine extraction, HI distillation, decomposition, recycle demonstrated – Diagnostics, control, flow systems developed and tested, reliable

• Bunsen reactor section testing (CEA)– First Bunsen reaction test completed - produced and separated HIx (heavy) phase

and H2SO4 (light) phase acids– Subsequently processed by HI section to produce H2– SO2/O2 separation section operated reliably in multiple operations

• H2SO4 decomposition experiments (SNL)– Acid vaporization, decomposition, and recuperation in one integrated SiC bayonet

unit, no corrosion issues identified in multiple test series– Experiments completed at 850 C, ambient to 5 bar, ~300 l/hr SO2 at 40 mole %,

SO2 conversion at ILS flow rates ~90% of theoretical– Operated in integrated mode with CEA Bunsen section March, 2008

• Next steps – diagnostics and equipment modifications, and complete FY08 testing program

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H2SO4 in

SO2, O2H2O out

catalyst Heat

Heat

Heat

H2SO4 (l) → H2O (g) + SO3 (g) ~ 500 CSO3 (g) → SO2 (g) + 1/2O2 (g) ~ 800 C

• Minimizes high T corrosion and connections

• Heat recuperation• Commercially

available materials for low T systems

• Scales as tube and shell HX

Sulfuric Acid Decomposition SectionSiC Integrated Decomposer

SO2, O2, to Bunsen

AcidConcentrator

Water Vapor Out

WaterCondenser

ConcentratedAcid Feed Tank

40 m/o Acid Out

WaterTank 1

Sulfuric AcidDecomposer

UndecomposedAcid Tank

Undecomposed Acid Recycle

WaterTank 2

WaterCondenser

ACID CONCENTRATIONACID DECOMPOSITION

SO2, O2, H2O, and acid out

Dilute 20 m/o H2SO4 input from Bunsen

H2O to Bunsen SectionH2O to Bunsen

SectionH2SO4 decomposer unit installed at

GA ILS experiment site

SIC Bayonet Decomposer

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16 17Time of Day (hr:min)

0

5

10

15

20

Aci

d Fl

ow R

ate

(mol

/hr)

16:10 16:20 16:30 16:40 16:500

50

100

150

200

250

300

SO2 Flow

Rate (l/hr)

← Acid

SO2 →40 mol% Acid

Sulfuric Acid Decomposition SectionResults

12 13Time of Day (hr:min)

0

25

50

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150

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200

Sul

fur D

ioxi

de F

low

Rat

e (li

ters

/hr)

12:10 12:20 12:30 12:40 12:50

3 bar

2 bar

1 bar

Pressure dependence of SO2 production rate. (1, 2, and 3 bar pressure, 7.1 m/hr)

..

SO2 Production versus Acid Flow Rate (40 m/o, 850 °C)

12 13Time of Day (hr:min)

20

30

40

50

Oxy

gen

Con

cent

ratio

n (%

)

12:10 12:20 12:30 12:40 12:50

Oxygen concentration in product gas stream -67% SO2 and 33% O2

SiC Bayonet Decomposer (ILS)• ~ 300 l/hr SO2 production rate @ 850 C (10

moles/hr, 40 mole% concentration)• Conversion rates ~90% of theoretical• SO2 production rate limited by heat transfer to

catalyst region• Pressure, flow rate dependence evaluated• Acid decomposer operation reproducible

through ~20 cycles• Catalyst durability requires further

development

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• Catalyst stability for extended operation remains a key issue• Supports studied: SiO2, γ-Al2O3, ZrO2, α-Al2O3 and TiO2, Pt/TiO2 most stable in

short term tests• Some complex metal oxides show high activity above 825°C• Stability of some complex metal oxides appeared promising • Further investigation of complex metal oxides anticipated in FY09

SO2 yields with temperature SO2 production rate, 850°C

0%

10%

20%

30%

40%

50%

60%

70%

80%

700 725 750 775 800 825 850 875 900 925

Temperature (C)

SO2 Y

ield

(mol

e %

)

CuCr2O4CuFe2O4

NiCr2O4NiFe2O4MnTiO3FeTiO3

1% Pt/TiO2

CuCr2O4

CuFe2O4

NiCr 2O4

NiFe2O4

MnTiO3

FeTiO3

Pt/TiO2

CuCr2O4

CuFe2O4

NiCr 2O4

NiFe2O4

MnTiO3

FeTiO3

Pt/TiO2

WHSV = 50 g acid/g cat./hr

0%

10%

20%

30%

40%

50%

60%

70%

80%

700 725 750 775 800 825 850 875 900 925

Temperature (C)

SO2 Y

ield

(mol

e %

)

CuCr2O4CuFe2O4

NiCr2O4NiFe2O4MnTiO3FeTiO3

1% Pt/TiO2

CuCr2O4

CuFe2O4

NiCr 2O4

NiFe2O4

MnTiO3

FeTiO3

Pt/TiO2

CuCr2O4

CuFe2O4

NiCr 2O4

NiFe2O4

MnTiO3

FeTiO3

Pt/TiO2

WHSV = 50 g acid/g cat./hr

0

1

2

3

4

5

6

7

8

0 40 80 120 160Time on Stream (hrs)

SO2 P

rod.

Rat

e (m

ol/h

r/g o

f Cat

alys

t) CuCr2O4CuFe2O4NiCr2O4NiFe2O4MnTiO3FeTiO3

WHSV = 2,000 g acid/g cat./hr, 850°C

CuCr2O4

CuFe2O4

NiCr 2O4

NiFe2O4

MnTiO3

FeTiO3

CuCr2O4

CuFe2O4

NiCr 2O4

NiFe2O4

MnTiO3

FeTiO3

1% Pt/TiO2

•CuCr2O4, NiCr2O4, FeTiO3- leaching problems

•Activity of FeTiO3 and NiFe2O4 decreased at the highest temperature

•Cu Fe2O4 spinelpromising at high temperatures

Sulfuric Acid Decomposition CatalystsINL H2SO4 Catalyst Studies

CuCr2O4

CuFe2O4Pt/TiO2

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Extraction

AcidConcentration

Distillation

Reaction

Separation

HIx

HI, H2O, H3PO4I2 to section 1

ConcentratedH3PO4

HIDilute H3PO4

HI, H2, I2

H2I2 to section 1

HI

Extraction

AcidConcentration

Distillation

Reaction

Separation

HIx

HI, H2O, H3PO4I2 to section 1

ConcentratedH3PO4

HIDilute H3PO4

HI, H2, I2

H2I2 to section 1

HI

Extractive distillation method • H3PO4 – separates HI/H2O from I2• HI distilled from H3PO4, • HI decomposed at ~ 400 C to H2 and I2• Undecomposed HI recycled to HI reactor• I2 returned to Bunsen reactor section

Key Issues • Uncertainty in HI/I2/H2O VLE • Materials – corrosion, catalysts

Section 3- HI DecompositionOverview

Iodine Extraction

HI Reactor

HI / H3PO4Distillation

H3PO4Concentrator

HI Decomposition section (section 3)installed at GA ILS site

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Section 3- HI Decomposition SectionFirst HI section H2 run with Bunsen section feed

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0:00:00 1:12:00 2:24:00 3:36:00 4:48:00 6:00:00 7:12:00 8:24:00

Elapsed time (hrs)

Tem

pera

ture

(deg

C)

TT_204TT_206TT_213ATT_213BTT_213CTT_213DTT_213ETT_213FTT_213G

HI distillation column temperature profile at 5 bar, integrated run

300

350

400

450

500

550

0:00:00 1:12:00 2:24:00 3:36:00 4:48:00 6:00:00 7:12:00Elapsed time (hrs)

Tem

p (d

eg C

)

TT_300BTT_300CTT_300D

HI adsorption/reaction temperature front moving through HI reactor

HI feed in HIx 17 mol/hr HI distilled to reactor 8.5 mol/hr

Predicted H2 produced with no recycle

0.85 mol/hr (19 l/hr)

H2 actually produced 2.7 mol/hr (60 l/hr)

Extraction

AcidConcentration

Distillation

Reaction

Separation

HIx

HI, H2O, H3PO4I2 to section 1

ConcentratedH3PO4

HIDilute H3PO4

HI, H2, I2

H2I2 to section 1

HI

Extraction

AcidConcentration

Distillation

Reaction

Separation

HIx

HI, H2O, H3PO4I2 to section 1

ConcentratedH3PO4

HIDilute H3PO4

HI, H2, I2

H2I2 to section 1

HI

-10

0

10

20

30

40

50

60

70

2:24:00 3:21:36 4:19:12 5:16:48

Elapsed time (hrs)

H2

flow (l

/hr)

Bottom

Middle

Top

H2 integrated production run ~50 l/hr with partial recycle

HI Boiler ~ 175 C

H2 rate after flow equilibration

HI Recycle Effect (5 bar)

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CEA Bunsen Section assembled at GA experiment site.

CEA Counter-current Bunsen Reactor Section

Bunsen Section Status (CEA)

H2SO4 to Skid 2

Pressure control

I2 from Skid 3

H2O from Skid 3

HIx to Skid 3GaseousSO2 + O2

from Skid 2

H2O from Skid 2

SO2 / O2separation

column

Liquid SO2

Bunsen reactorSO2 / O2

compressor

GaseousO2 + SO2

O2

H2O + SO2

SO2 / O2buffer tank

SO2 / O2liquid / gasseparator

H2SO4density control

SamplingSampling

Effluents

To scrubber

Safety valve

Closed inoperation

3 wayvalve

Pump

Back pressure

check valve

SO2/O2 separation

Bunsen Reactor

SO2 /O2Section

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SO2 + 2 H2O + I2 H2SO4 + 2 HI

I2

H2SO4

HI

H2OSO2

HI

H2SO4

Bunsen Section Status (CEA)Counter-current Bunsen reactor – initial run

Initial Test Results• First Bunsen reaction completed in

April with H2SO4 section• Heavy phase - 42% HI, 10% I2 –

acceptable for processing in HI section

• Light phase density 1.23, target 1.5• Testing will resume after installation

of modified Bunsen reactor

• SO2, H2O and I2 react to form HI and H2SO4

• HIx (HI, H2O, I2) to section 3 (heavy phase)

• H2SO4, H2O to section 2 (light phase)

9 I2 + SO2 + 16 H2O = 2 HI + 10 H2O + 8 I2 + H2SO4 + 4 H2O

• Improved I2 pumping and metering required

• CEA will install new top reactor section to include DP cells for liquid level control (May 2008)

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Sulfur Cycle Supporting ActivitiesSystem Analyses

Cost Analyses (H2A)• Development of H2A cost

framework for NHI processes (TI, MPR)

• Update capital, operating cost estimates, performance based on updates from process teams

• Consistency, uncertainty review at MPR (FY08), H2A analyses for updated cost estimate

• FY07 update (preliminary draft)

NHI Baseline Cycle

H2 Cost ($/kg) Efficiency (H2A Analysis)

Sulfur-Iodine (extractive distillation)

3.41 40

Sulfur-Iodine (reactive distillation)

3.05 39

Hybrid Sulfur

2.94 43

High Temperature Electrolysis

3.22 44

FY07 NHI Baseline Process Cost Projection Update

• Efficiencies based on available flowsheets

• Cost of energy - Electricity = 0.06 $/kWhr- Thermal = 0.02 $/kWhr

Other assumptions- Low temp electrolysis – 660 $/kWe- High temp electrolysis – 500 $/kWe

$0.50

$1.00

$1.50

$2.00

$2.50

$3.00

$3.50

$4.00

$4.50

$5.00

20 25 30 35 40 45 50 55 60 65 70

Electricity price, $/MWh

Hyd

roge

n pr

ice,

$/k

g

Conventional Atmospheric Alkaline Electrolysis Conventional SMR (w/o CO2 removal) Advanced SMR (with CO2 removal)

Natural Gas Price, $/MMBtu4.0 6.05.0 7.0 9.08.0 11.010.0 12.0 14.013.0 16.015.0

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Sulfur Iodine Thermochemical CyclePlanned Activities - FY08 - FY09 (tbd)

• FY08 – Complete Phase 2 test program in ILS apparatus– Process improvements, equipment modifications

• Level diagnostics for Bunsen reactor - achieve flowsheet light and heavy acid phase characteristics,

• Smaller HI reactor to facilitate section 3 flow control, • Interface unit diagnostics for extended operation

– Establish baseline operational data for integrated operations, HI extractive distillation, and counter current Bunsen reactor

• FY09 – TBD – examine improved /alternate process options

• Complete investigation of operational characteristics and performance for current configuration, extended operations

• Consider reactive or co-current options • Complete assessment of S-I for nuclear hydrogen

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Sulfur-Iodine ILS Experiment Project Summary

Relevance: This project is providing the technical information needed to assess the potential of the Sulfur Iodine thermochemical cycle for large scale production of hydrogen using Generation IV reactors. Results from this project will support the DOE FY2011 technology decision for the NGNP hydrogen production technology.

Approach: Flowsheet analysis identified process options for the S-I cycle. Laboratory experiments evaluated process options and provided the basis for the design and testing of the 3 major reaction sections of the S-I cycle.

Technical Accomplishments: The 3 major reaction sections of the S-I cycle have been assembled at the integrated lab scale experiment site and initial testing has been initiated. SNL has completed testing of a SiCbayonet sulfuric acid decomposer section at the GA site and conducted initial integrated operations with the CEA. The CEA has completed the first Bunsen reactor test, producing and separating the heavy (HI) and light (H2SO4) phase acids for subsequent processing. GA has completed the initial H2 production runs on the HI extractive distillation and decomposition section.

Tech Transfer/Collaboration: The S-I cycle research is conducted as an INERI project with the French CEA. There is also collaboration with Universities (chemical analyses, materials). The DOE sponsored work will be a major component in the Generation IV International Forum (GIF) nuclear hydrogen collaboration signed in March FY2008.

Future Research: The focus in FY08 will be to complete the initial series of ILS test in the current configuration. FY09 is TBD but the possibility of examining advanced process options is a primary consideration. Research on improved catalysts will also be conducted.