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Experimental and Analytical ResultsExperimental and Analytical Resultson Hon H22SOSO44 and SOand SO33 DecomposerDecomposer
for IS Process Pilot Plantfor IS Process Pilot Plant
A. Terada, Y. Imai, H. Noguchi, H. Ota, A. Kanagawa, S. Ishikura, S. Kubo, J. Iwatsuki, K. Onuki and R. Hino
Nuclear Energy Basic Engineering Research SectorJapan Atomic Energy Agency
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Nuclear HeatNuclear HeatHydrogenHydrogen OxygenOxygen
H2O22
1
900 C400 C
Rejected Heat 100 C
Rejected Heat 100 C
S (Sulfur)Circulation
SO2+H2O+
O221
H2SO4
SO2+
H2OH2O
H2
I2
+ 2HI
H2SO4
SO2+H2OH2O
+
+ +
I (Iodine)Circulation
2H I
I2
I2
WaterWater
Nuclear HeatNuclear HeatHydrogenHydrogen OxygenOxygen
H2O22
1 O22121
900 C400 C
Rejected Heat 100 C
Rejected Heat 100 C
S (Sulfur)Circulation
SO2+H2O+
O221
H2SO4
SO2+
H2OH2O
H2
I2
+ 2HI
H2SO4
SO2+H2OH2O
+
+ +
I (Iodine)Circulation
2H I
I2
I2
WaterWater
100J
76J24J
33J
67J
Nuclear HeatNuclear HeatHydrogenHydrogen OxygenOxygen
H2O22
1
900 C400 C
Rejected Heat 100 C
Rejected Heat 100 C
S (Sulfur)Circulation
SO2+H2O+
O221
H2SO4
SO2+
H2OH2O
H2
I2
+ 2HI
H2SO4
SO2+H2OH2O
+
+ +
I (Iodine)Circulation
2H I
I2
I2
WaterWater
Nuclear HeatNuclear HeatHydrogenHydrogen OxygenOxygen
H2O22
1 O22121
900 C400 C
Rejected Heat 100 C
Rejected Heat 100 C
S (Sulfur)Circulation
SO2+H2O+
O221
H2SO4
SO2+
H2OH2O
H2
I2
+ 2HI
H2SO4
SO2+H2OH2O
+
+ +
I (Iodine)Circulation
2H I
I2
I2
WaterWater
100J
76J24J
33J
67JIS Process
- H2 is produced by thermal decomposition of HI at ca. 400℃, and O2 is produced by thermal decomposition of H2SO4 below 900℃. (Pyrolysis of water; Heat more than 4000℃)
- Iodine and sulfur compounds are used as recycling materials under thermochemical close cycleHydrogen iodide (HI) Sulfuric acid (H2SO4)
decomposition Bunsen decomposition (endothermic) reaction (endothermic)
Thermochemical Iodine-Sulfur (IS) Processdeveloping IS process aiming to realize nuclear hydrogen production
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High pressure(up to 2MPa)
High pressure(up to 2MPa)
Atmospheric pressure
Pressure of chemical process
FY 2009 – 2014(under planning)
FY 2005 – 2010(under planning)
FY 1999 - 2004Time
Heat exchangerwith helium gas
(Nuclear heat 10MW)
Heat exchangerwith helium gas
(Electrical heater 0.4MW)Electrical heaterHeat supply
Industrial materialIndustrial material
(SiC, coated) GlassMaterial of
chemical reactors
～1000 m3/h～30 m3/h～ 0.03 m3/hHydrogen production rate
HTTR Test nuclear demonstration
Pilot TestBench-scaled Test
Next Step : Pilot Test (JAERI’s Plan)On the basis of the hydrogen production test results and know-how obtained with the bench-scale test apparatus and other R&Ds
To confirm continuous hydrogen production under simulated HTGR operations and fabricability of components, and to establish technology base for realizing high thermal efficiency more than 40%.
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Flow Diagram of IS Process Pilot Plant ( tentative )Existing He circulation facility (He Loop)
H2
I2
SO3
SO2 O2
O2
I2
H2SO4
SO3Decomposer
HIDecomposer
880℃
150℃
He Circulator
SteamGenerator
HI DistillationColumn
PurifierConcentrator
～450℃
HI
He gas(4MPa)
ElectricHeater
H2SO4Decomposer
Purifier
Condenser
H2SO4 / HIx (HI+I2) Separator
BunsenReactor
Condenser
～850℃
～500℃
H2O
He gas
He gas
IS Process Pilot Test Plant (2MPa)
400kW
～120℃
30Nm3/hH2
Sulfuric Acid (H2SO4) Decomposition HI Decomposition
Electro-Dialyzer
Cooler
Steam
Steam ～250℃
Steam
Conceptual design (system, components) : taking into account of effective heat recovery including efficient HI concentration by using electro-dialysis, so as to increase system efficiency.
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Concept of H2SO4 Decomposer for Pilot Test Plant
φ0.7m 1.5m
3.1m
He outlet
He inlet
Gasket(Au)
φ0.25m
H2SO4outlet
SiC block
H2SO4 inlet
He outlet
He inlet
SO3+H2O outlet
H2SO4 inlet
Thermal insulation
SiC block
82.7 kWThermal Rating
0.066 kg/sProcess Flow Rate
0.091 kg/sHe Flow Rate
2 MPaGProcess Pressure
4 MPaGHe Pressure
435 / 460 ℃Process Inlet / Outlet Temp.
710 / 535 ℃He Inlet /Outlet Temp.
ConditionsItems
The concept of the H2SO4decomposer is a counter-flow type heat-exchanger made of SiC, which works as an H2SO4 evaporator.
Ref) H. Ota et al., 13th Int. Conf. Nuclear Engineering (ICONE13), Beijing, China, May 16-20, 2005, ICONE13-50494H. Ota et al., 2005 Ibaraki Meeting of the Japan Society of Mechanical Engineers, Hitachi-taga, Ibaraki, Japan, September 9, 2005.
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0
100
200
300
400
500
600
700
800
0.00 0.30 0.60 0.90 1.20 1.50
Distance from SiC block inlet (m)
Tem
pera
ture
(℃
)He
H2SO4 Superheat region
Sub-cooled region
Axial Temperature Distribution
Structure Analysis of H2SO4 Decomposer (1/2)
Ref) H. Ota et al., 13th Int. Conf. Nuclear Engineering (ICONE13), Beijing, China, May 16-20, 2005, ICONE13-50494
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Structure Analysis of H2SO4 Decomposer (2/2)
1/4 modelof SiC block
Temperature distribution
・Heat Transfer and Stress Analysis of SiC Block– Max.ΔT=250℃ and ΔP=2MPa : Max. stress=114MPa– Average tensile strength of SiC = 250 MPa
H2SO4
channel
Dryout level
Stress distribution(thermal stress + static stress)
H2SO4 channel He channel
Max. stress114 MPa
He channel
Ref) H. Ota et al., 13th Int. Conf. Nuclear Engineering (ICONE13), Beijing, China, May 16-20, 2005, ICONE13-50494
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Upper SiC block(φ0.25×0.75 m）
We confirmed fabricability of the SiC block assembly.
Test Fabricated SiC Block Assembly - Mock-up Model-
Ref) H. Ota et al., 13th Int. Conf. Nuclear Engineering (ICONE13), Beijing, China, May 16-20, 2005, ICONE13-50494H. Ota et al., 2005 Ibaraki Meeting of the Japan Society of Mechanical Engineers, Hitachi-taga, Ibaraki, Japan, September 9, 2005.
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Test condition：
3 heat cycle up to 500℃Outer press. :VacuumInner press. :4MPa
Water press.
He gas press.
He leak detector
Metal O-ring
Gasket
SiC block Flange
SiC blockVacuum furnace
Seal performance test
Gold cap gasket
n Test method
Leak test model
SiC block (120mmφ 50mmt)
Attachment of gold cap gaskets（19mmφ)
n Test results
Helium leak rate was 7.5x10-8 Pa･m3/s at the connection of SiC blocks, which was much less than the LWR rubber seal standard of 1x10-4 Pa・m3/s.
Seal Performance Test with Mock-up Model of H2SO4 Decomposer
n Objectives
To confirm applicability of a gold seal for boundary between sulfuric acid (liq. or gas) and helium
Ref) H. Ota et al., 13th Int. Conf. Nuclear Engineering (ICONE13), Beijing, China, May 16-20, 2005, ICONE13-50494
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PE
PE
LE
TE
TE
TE
TEPE
TE
LE
FE
TE
LE
TE
PETE
TE
FE
PE
PE
Boiling heat transfer test loop（Heat transfer measurements
and flow-visualization）
Component test loop（ Performance & integrity of
H2SO4 components）
H2SO4 Thermal-Hydraulic Test Loop
LE
TE
FE
PE
Level gauge
Thermocouple
Flow meter
Pressure gauge
Glass lining pipingCooler
Expansion tank Expansion tank
Cooler
Gear pump
Heater
Heater
Gear pump
Dump tank
N2 gas
Catch pan
Temp. : Max. 320℃Press. : Max. 0.95MPa
Max. flow rate : 2.5L/min Max. flow rate : 20 L/min
Ref) H. Ota et al., 2005 Ibaraki Meeting of the Japan Society of Mechanical Engineers, Hitachi-taga, Ibaraki, Japan, September 9, 2005.
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Outer View of H2SO4 Thermal-Hydraulic Test Loop
Ref) H. Ota et al., 2005 Ibaraki Meeting of the Japan Society of Mechanical Engineers, Hitachi-taga, Ibaraki, Japan, September 9, 2005.
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He inlet
Thermal insulator
SiC plate typedecomposer
Pressure vessel
1200
Process gas
outlet
300
Process gas inlet
He outlet (unit: mm)
4200
φ1000
He inlet
Thermal insulator
SiC plate typedecomposer
Pressure vessel
1200
Process gas
outlet
300
Process gas inlet
He outlet (unit: mm)
4200
φ1000
He gas flow channel(height: 2.5mm)
SiC plates in one stage
Process gas flow channel
Structure of the SO3 decomposer unit (composed of 6 plate-type heat exchangers connected in series)
Concept of the SiC plate type SO3decomposer for pilot test plant
H2SO4 evaporates, and some amount of H2SO4 vapor is decomposed into SO3 gas and water vapor by high temperature heat supplied from the existing helium gas loop.
nthe internal volume charged with catalyst is about 25 liters, nand then, the space velocity (SV) becomes about 5500 h-1.
Concept of SO3 Decomposer - counter flow type heat exchanger -
Ref) A. Kanagawa et al., 13th Int. Conf. Nuclear Engineering (ICONE13), Beijing, China, May 16-20, 2005, ICONE13-50451
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Thermal-Hydraulic Analytical Results- middle stage of the decomposer -
outlet 558oC
Inlet 625oC
minimum 532oC
maximum 601oC
Temperature distribution in SO3 flow path
Inlet 527 o C
maximum 597 o C
maximum 0.50m/sminimum 0.28m/s
33rd stage
SO3 gas flow velocity distribution
Temperature distribution in He flow path Temperature distribution in solid unit
Ref) A. Kanagawa et al., 13th Int. Conf. Nuclear Engineering (ICONE13), Beijing, China, May 16-20, 2005, ICONE13-50451
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Contour in 1st stage
maximum 53MPa
Contour in process gas channel
maximum 14MPa
nAnalytical resultsLeg Part Max 53 MPa Process-gas side Max 17 MPa (surface)
nAnalytical results in all places were below the tensile stress of SiC.
Structure Analysis of SO3 Decomposer
Stress distributions(thermal stress + static stress)
Ref) A. Kanagawa et al., 13th Int. Conf. Nuclear Engineering (ICONE13), Beijing, China, May 16-20, 2005, ICONE13-50451
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788mm
317mm
208
1st stage
Process gas inlet
2nd stage Process gas outlet
Mock-up Model of Plate-Type SO3 Decomposer
A SO3 decomposer model consisting of 2 heat exchanger stages to confirm fabilicability and its mechanical strength.
It was very difficult to connect two stages without cracks.It is necessary to improve a sintering connection technique between stages.
Ref) A. Kanagawa et al., 13th Int. Conf. Nuclear Engineering (ICONE13), Beijing, China, May 16-20, 2005, ICONE13-50451
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Flow Sheet of Catalyst Test Apparatus for SO3 Decomposition
P
SO2
Analyzer
HTE
H
H
H H2SO4Pump
Ar
H2SO4Evaporator
Catalyst Bed(Pt/SiO2)
Test Section
H2SO4Tank
Condenser
Water
H2SO4Drain SO2Trap
PressureControl Valve
Charcoal filter
Thermocouple
Pressure gauge
Electric heater
P
H
TE
O2,Ar
Experimental conditions:Temp. : 753℃Pressure : 0.31MPa Space velocity : 1000h-1
SO3 decomposition ratio:52.7 % ( ≒56.3% of
equilibrium ratio)
Ref) A. Kanagawa et al., 2005 Ibaraki Meeting of the Japan Society of Mechanical Engineers, Hitachi-taga, Ibaraki, Japan, September 9, 2005.
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• ConclusionØ Concepts of the H2SO4 and SO3 decomposers made of SiC
ceramics for the pilot test plant have proposed featuring corrosion resistant performance under high-temperature H2SO4 and SO3 operations.
Ø The feasibility of the proposed concepts has confirmed by thermal-hydraulic and mechanical strength analyses and test fabricated mock-up models.
• Future workØ To accumulate design data for the pilot test plant, we will
confirm the thermal-hydraulic performance of the H2SO4decomposer and the SO3 decomposition performance in the packed catalyst layer by using the sulfuric acid flow test loop and the catalyst test apparatus.
Summary
