20 years of german r&d on nuclear heat applications
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20 Years of German R&D on Nuclear Heat Applications
Werner von Lensa, Karl Verfondern
Research Centre Jülich, Germany
4th Int. Freiberg Conference on IGCC & XtL Technologies – IFC2010
May 3-6, 2010, Dresden, Germany
Coal Refinement
790 kWh electricity
360 kg coal dust
250 kg charcoal
280 l methanol
160 l gasoline
550 m3 synthesis gas
150 m3 SNG
Conversion of 1000 kg of lignite
Conventional vs. Nuclear Technologies
Hot flue gas -> Steam generation
BUT: CO2 Emission
Chemical Reactions ~ 5 eV
Closed CO2 or He Circuit -> GCR
No CO2 Emission !
Nuclear Reaction ~200 MeV
40 Million more energy per reaction !
Steam
Firing Chamber
High-Temperature Gas-Cooled Reactor: Fully Ceramic Fuel Element
Temperature Resistant up to 1600°C
No Release of Fission Products
Main
Innovation
Prismatic Block-type Fuel
Fuel-Compacts
Flexibility in Application & Fuel
LEUTRISO
LWR-Wastein TRISO c.p.
WeaponPlutonium
TRISO
TRISO Fuel in graphite blocks
(or pebbles)
Pure Weapon -Pu, small ParticlesTRISO Coating750,000 MWd/HMt burn-up
Minor Actinides from reprocessing ofLWR Fuel, small particlesTRISO - Coating700,000 MWd/HMt burn-up
LEU C.-PartikelTRISO coated 100-150 GWd/HMt burnup
Electricity
Hydrogen
Process heat
One Reactor Design for different Applications
Thorium
Temperature Ranges Provided and Required
Prototype Nuclear Process Heat (PNP) Project
Identify suitable coal gasification processes on lab scale
Test selected processes on semi-technical scale
Construct and operate pilot plants for selected processes
Design large-scale nuclear plant for process heat prod.
Construct and operate prototype nuclear coalgasification plant
Construct and operate commercial nuclear coalgasification plant
20 years Duration: 1970s – 1990s
Drivers for Nuclear Coal Gasification
Resource savings of up to 40 %
Respective reduction in CO2 and other coal-specificemissions
Reduction and diversification of dependency on oil importsif coal is converted to liquid hydrocarbons
Help to meet growth rates in energy consumption and substitute for expensive electricity production with fossil fuels (if cost of nuclear heat is sufficiently low)
Design of PNP-3000 Nuclear Process HeatPlant
Thermal Power: 3000 MW(th)Power Density: 5 MW/m3
He inlet/outlet: 300/950°COTTO fuel loading scheme6 main loops with SR+SG or IHX4 decay heat removal systemsPrestressed concrete pressure vesselor Prestressed Cast-Iron Reactor
Pressure Vessel
Prototype Plant PNP-500
50 t/h coal41,000 m3 SNG
166 t/h coal26,500 m3 SNG + 18.4 t/h charcoal
HTGR
Steam gasificationof hard coal
Hydro gasificationof lignite
Alternative: HTR-Modul
Principal Lines of Steam-Coal Gasification
counter-current co-current co-current10-30 mm 1-10 mm < 0.1 mm60-90 min 15-60 min < 0.02 min370-600°C 800-950°C 1400-1600°C
Coal Gasification with Nuclear Energy
with steam: C + H2O H2 + CO - HCO + H2O H2 + CO2
------------------CO + 3 H2 CH4 + H2O
with hydrogen: C + 2 H2 CH4 + H
------------------CH4 + H2O CO + 3 H2 - H
CO + H2O H2 + CO2
Nuclear Steam Coal Gasification
Steam Coal Gasifier Design forPrototype Plant
Thermal Power: 340 MWCoal throughput: 50 t/hEffective volume: 318 m3
Heat exchanging area: 4000 m2
Nuclear SimulatedSteam Coal Gasification
Lab scale testing:1973-1980 with 5.0 kg/h
Semi-technical scale testing: 1976-1984 with 0.5 t/h
Gasification: at 750-850°C and 2-4 MPa
Total coal gasified: 2413 tOperation time: ~26,600 h with
~13,600 h under gasification cond.
Allothermal Gas Generator (Pilot Plant)Parameter Value
Thermal power [MW] 1.2
Helium inlet temperature [°C] < 1000
Helium flow [kg/s] 1.1
Heat exchanging surface [m2] 33
Height [m] < 4
Cross section [m2] 0.8 * 0.9
Fluidized bed density [kg/m3] 344
Coal input [kg/h] 233
Coal particle size [mm] < 1
Steam velocity [m/s] 1.13
Gasification temperature [°C] 700 - 850
Pressure [MPa] 4
Raw gas production rate [Nm3/h] 816
Conversion rate [%] 83
FIG. 3. Schematic of allothermal
gas generator.
Gas Composition after Steam Coal Gasification
High pressure increases methane content good for SNG productionHigh temperature increases hydrogen content good for syngas production
9-Days Test RunTest run with highly volatile caking coal
Constant levels of product gas components reveal operationwith no problem
Catalytic and Non-Catalytic GasificationA number of tests with K2CO3to accelerate reaction rate
Modest effect for 2 or 3 %, but large one for 4 %
Fluidized bed temperaturedecreased (as was predicted)
Catalytic and Non-Catalytic Gasification
Parameter Non-Catalytic Catalytic
Pyrolysis Gasification Pyrolysis Gasification
Helium temperature [°C] 895 895
Gasification temperature [°C] 805 701
Reaction enthalpy [kJ/kg coal] 2192 5678 2058 5148
Coal throughput [t/h] 27.3 69.3
Raw gas production rate [Nm3/h] 234,000 659,500
Gas composition fractions [%] H2: CO: CO2: CH4:
44.2 11.1 19.2 23.7
53.5 12.7 25.8 7.4
57.6 1.1 25.9 14.5
57.2 2.4 32.7 7.3
10 MW(th) Helical IHX
Steinmüller
10 MW(th) U-Tube IHX
Balke-Dürr
10 MW(th) Component Test Loop (KVK)
Thermal Power: 10 MW(th)Helium flow: 3.2 kg/sMax. He temp. prim/sec: 950/900°CSystem pressure: 4 MPaOperation time: ~13,000 h
Hot gas duct
IHX Header and Hot-Gas Valve Tests
Nuclear Hydrogenating Coal Gasification
10 MW(th) Steam Reformer
EVA-II reformer tube bundleat the Research Center Jülich
Technical Data of EVA-II/ADAM-II
Power Input 10 MW(e)Cooling gas flow rate 4 kg/s of heliumPressure 4 MPaTemperature max/min 950/350 °CSG temperature/pressure 700 °C / 5.5 MPaMethane input 0.6 kg/sSteam reforming temp. max 820 °CMethanation temp. max 650 °CADAM-II heat release rate 5.3 MW(th)
_____________________________________________From 1981 - 1986: 13,000 hours of operation, of which
7750 h at 900 °C and 10,150 h as complete process
Pilot Plant forHydro Coal Gasification
Semi-technical scale testing: 1975-1982 with 0.2 t/h
Pilot plant scale testing:1983-1986 with 10.0 kg/h
Gasification: at 850-950°C and 6-12 MPa
Coal throughput: ~40,000 twith up to 6400 Nm3/h of SNG
Operation time: ~8000 h
Methanation(Long-Distance Energy Transport)
EVA-ADAM facility at FZJ
Hydrogen & Process Heat for Refineries
Increasing Demand for Cogeneration of Heat, Power & Hydrogen
Plus Heat !
Plus Heat !
Hydrogen Short-Term Option: Electrolysis
Electrolysis ideal for remoteand decentralized H2 production
Off-peak electricity from existingNPP (if share of nuclearamong power plants is large)
As fossil fuels become more expensive, the use of nuclear outside base load becomes more attractive
200 m3/h
Medium-Term Option: HT-Electrolysis
Increased efficiency
Reduced electricity needs
Capitalize from SOFC efforts
Next Step: Demonstration at HTTR
Containment
HTTR
Reactor(30 MW)
SteamReformer
Hot Gas Ducts
Control-CentreIHX (10 MW)
Heavy Oil RecoveryConventional: 2t OIP 1t Product + 2,5t CO2Nuclear: 2t OIP + 12 MWh 2t Product + no CO2
Methanol ProductionConventional: 300m3 Gas 1t Product + 1,5t CO2Nuclear: 300m3 Gas + 3MWh 2t Product + no CO2
Oil ShaleConventional: 12t Shale 1t Product + 2,5t CO2Nuclear: 12t Shale + 12 MWh 2t Product + no CO2
Biomass ConversionConventional: 12t Biomass 1t Product (CH3OH)Nuclear: 12t Biomass + 10 MWh 2t Product
Double Yield from Energy Resources by NPH !Important Contribution to SUSTAINABILITY !
CO2 Reduction & Gain in Resources
Potential Arrangement of 600 MW VHTR for H2 Production
H2storage
Reactor building
Heat exchangeThermo-chemical
Water splittingprocess
from CEA
Potential Hazards in CombinedNuclear/Chemical Plants
Tritium transportation from core to productgases and hydrogen in opposite direction;
Thermal turbulences induced by problemsin steam reforming system;
Fire and explosion of flammable mixtureswith process gases.
Tritium in German Legislation
According to German Preventive RadiationProtection Ordinance, specific radioactivitylimit for any fabricated product is500 mBq/g.
Exception from the rule:No licensing required for fossil products to berefined by nuclear process heat with tritiumcontent < 5 Bq/g.
Sources:- fission (51%)- lithium (34%)- helium (15%)
Problem Tritium
High mobility of both HT and H2 at high temperatures- radiation problem to consumer- corrosion problem in graphitic core structures
Measures of reducing HT and H2 transport- oxide layers (doping with O2)- gas purification system- intermediate circuit (doping with H2O)
Results from FZJ and JAEA calculations and tests- HT level in product gas deemed sufficiently low- permeability of oxide layer reduced by factor 100-1000
German BMI Guideline (1974)
Protection by means of design against pressure wave
German BMI Guideline (1974) for theProtection of NPP against External Explosions
R = 8 * M 1/3
TNT equivalent for explosives
100% for unsaturated HC and non-liquefied gases50% for gases liquefied under pressure10% for gases liquefied at low temperatures0.3% for combustible liquids
Minimum Distance: R ≥ 100 m
Protection by means of safety distance
German BMI Guideline (1976)
Guideline was the result of experts‘ opinion.
Guideline was confirmed by PNP gas cloud programthat gas mixtures typical for PNP cannot generatepressures beyond the design curve.
However, Guideline must not be applied to processheat HTGRs.
If applied to HTTR/SR:k = 3.7 R = 205 m for LNG storage tank(not considered: inventory in steam reformer)
LNG: 400 m3 169 t 1859 t TNTR = 2.2 km
(or show that attendant risk be sufficiently low)
US Regulatory Guide 1.91 (1975)
Flame Velocities of H2-CO-Air Mixtures
Danger of Deflagration to Detonation Transition
Results from Coal Gasification Activities
Coal conversion using nuclear energy can save up to 40 % of resources.
Various coal conversion processes were developedand successfully tested in a wide range of operationparameters and coal types.
Technical feasibility of an allothermal gas generator as (the only) new component was successfullydemonstrated.
Key problem remains the selection of appropriatematerials (HX, gas generator), also with regard to catalytic coal conversion
General Achievements of PNP Project
Confirmation of technical feasibility of allothermal, continuous coal gasification
Manufacture and successful operation of high temperature heat-exchanging components
Demonstration of licensing capability of a nuclearprocess heat HTGR by resp. safety research
Economics to be re-evaluatedCompatible to actual European Energy Policy(e.g. SET Plan)
