Ammonia bottoming cycle

projectFranck David –EDF R&D

July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology – July 8th and 9 th 20082

Nuclear power plants : 58 plants + EPR Flamanville

EDF nuclear power plants

19 nuclear sites58 plants

July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology – July 8th and 9 th 20083

Water needs and consumption

EDF’s water needs

Water needs : 25 g / Kwh

River only

Needs : 15 g/kwh

Evap : 0,45 g/kwh

domestic Industry Agriculture electricitySurface water

underground water

July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology – July 8th and 9 th 20084

Review of EDF’s CYBIAM Project (Cycle Binaire Ammoniac)

Binary cycle overview

Experiments with the CYBIAM pilot

Economical studies

Modelling the cycle

Discussion…

*Based on review of documents available at EDF

Binary Cooling System

July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology – July 8th and 9 th 20085

Motivation for the R&D program

Context in France at the end of the 70th •An increase in electrity demand was expected•Reduction of investment costs larger Units

• 250 900 1300 Mwe

• major Limitation : sizes of the turbines• limitation with « direct cooling » capacities

Aim : To reduce turbine size by changing steam with a more dense vapor in the lowest pressure stages

July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology – July 8th and 9 th 20086

The H2O/NH3 cycle

The lowest pressure turbine stages in the vapor cycle and steam condenser are replaced with a NH3 cycle

Three specific components :

• Condenser/boiler

• NH3 turbine

• Dry cooling system (Air cooled condenser)d for

450mbar

20% PN80% PN

July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology – July 8th and 9 th 20087

Fluid selection

NH3 was selected among a lot of potential candidates•condensation at a higher pressure than external (ambiant) pressure• freezing Temp lower than any expected ambient Tre• relatively high critical point

•« Good » thermal hydraulic parametershigh heat capacity (latent heat)High density of vapor at ambient temperature

•Cost and availability•Risk and operation

EPRI ACT project used (on cooling technology) selected NH3

Tre (35°C) H20 R11 R12 NH3Psat (bar) 0,056 1,49 8,46 13,5Vvap(m

3/kg) 25,3 0,12 0,021 0,096L=Hv-Hl (kJ/kg) 2418 178 135 1123

July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology – July 8th and 9 th 20088

Additional advantagesNo water needs (dry cooling)Meet a general issue if limited cooling

capacity on french riversLarger choice for Plant constructions

Extra power supply capabilitycompared to steam cycle

Expected gain of efficiency : 0,45% / °C in winter (cold Temp.)

Power enhancement factor / ambient temperature

Design point

Binary cycle

Steam/water cycle

July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology – July 8th and 9 th 20089

Historic of the studies at EDF1970 1982 :

Preliminary studies : technical issues

Assesment of NH3 / no dissociation risks / heat exchange coefficient

Construction of a small pilot plant 600 kW and tests

1978 1979 and 1987 1989

Economical studies

Including

Cycle modelling

Contract with manufacturers / help from EDF Engineering Division

Value of electricity produeced during winter

1979 1987 : Pilot CYBIAM (CYcle BInaire à AMoniac)

Pilot experiment of 22MWe

Construction : 1980 1985

Operation and testing 1986 1989

July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology – July 8th and 9 th 200810

The Cybiam experiment feedback

Main features of the experiment

22 Mwe

Heat suply : 400°C et 18bars

Air cooled condenser

Technical aspects

Production of relevant and validated results / comparison with modelling

Know-how on NH3 risk managment

Operation : no particular difficulties for operating the 2 cycles

The gain of power during cold days has been (more or less) demonstrated

Main difficulties

Pump of NH3 (rapid degradations) as vapor can be entrained

prenvented by additional cooling system

July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology – July 8th and 9 th 200811

Economic studies (ref. year 1989) 1/3Economic studies include 3 main lines

Research / Development

Investment Costs

Exploitation expected returns

1 – R & Development Costs (1989!!!) MF M€

500 MF (75 M€) for development and for operating Cybiam 500 75

An intermediate step 250 Mwe is requiered (estimation 40 M€) 250 40

But : the Cybiam mock up has been dismantled and technical know-how has partially disapeared

July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology – July 8th and 9 th 200812

Economic studies (ref. year 1989) 2/3

2 – Investment Costs (compared with 1300 Mwe)

Two major factors of uncerntainties

Dry cooling system (air cooled condenser of NH3) (textile + natural draft)

Gain due to reduction of buildings for Turbine (reduction factor : 4)

More recent informations would requiere to ask manufacturer

Estimated costs (MF) 1300MW 1300MW Bin Diff

Turbine 762 524 -240 (-33%)

Cond/boiller 88 210 +122 (+120%)

CT/ACC 202 460 +258 (+130%)

Buildings 230 66 - 164 (-70%)

-22 (3,3 M€)

July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology – July 8th and 9 th 200813

Economic studies (ref. year 1989) 3/3

3 – Operation

Value of extra power was evaluated in a french (80’s) context

0,45% / °C

Gain of 1000MF (150M€) through the life of 1 Unit 1300 MWe

If cold Tre are available

Uncertainties

Disponibility of the Unit operating with NH3 : 0,8 / 0,85(H20)

Evolution of turbine capabilities (?)

Conclusion after 15 years of R&D

In 1990 : number of expected future plants were very little

Potential Interest for a minimun of 3 Units

R&D effort was stopped (more than 330 documents in reference)

July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology – July 8th and 9 th 200814

Current simulations with Thermoptim (1/3)

Objectives

Better understanding of the system / in addition to the review

Capacity to reproduce efficiency of a plant

Evaluate the interest of using Thermoptim

Thermoptim Tool

Capacity to model and design thermodynamic cycles

Optimisation capabilities / Library of numerous fluids

Helpfull for « pre design »

July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology – July 8th and 9 th 200815

Simulations (2/3) EPR plant

EPR plant combined with Binarybottoming cycle

Sensitivity to low steam pressure

Sensitivity to exchangers pinch

Sensitivity to ambiant temperature

Comparison with wet or dry cooling

July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology – July 8th and 9 th 200816

Puissance fournie

1690

1695

1700

1705

1710

1715

1720

0 100 200 300 400 500 600 700 800

Pression de coupure (mbar)

Puis

sanc

e (M

W)

Débit NH3

3820

3830

3840

3850

3860

3870

3880

3890

0 100 200 300 400 500 600 700 800

pression de coupure (mbar)

débi

t (kg

/s)

Puissance fournie

1200

1300

1400

1500

1600

1700

1800

-10 -5 0 5 10 15 20 25 30 35

Température éxterieure (C)

puis

sanc

e (M

W)

Pression aval turbine BP

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

-10 -5 0 5 10 15 20 25 30 35

Température Exterieure (C)

Pres

sion

(bar

)

Power delivered / steam turbine backpressure

Power delivered / air temperature

Simulations (3/3) EPR plant

1%

July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology – July 8th and 9 th 200817

ConclusionAs a conclusion

Previous studies at EDF show the interest of the binary cycle

It is difficult to get more accurate information on costs (how to extrapolate ?)

Technical know how is partially lost (but experiments are well documented)

The context has changed :

the system is economicaly interesting and needs no water

there is an increase in Plant developments (scaling factor)

Next possible steps

Assesment of costs with current and actual values

Combining the H2O/NH3 cycle with heat transfer improvments tested at Kern Station (25 yearsago)

opportunity to engaged new pilot ??