Ammonia bottoming cycle project Franck David EDF R&D
EDF nuclear power plants Nuclear power plants : 58 plants + EPR Flamanville 19 nuclear sites 58 plants 2 July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology July 8th and 9 th 2008
EDF s water needs Water needs and consumption Water needs : 25 g / Kwh River only Needs : 15 g/kwh Evap : 0,45 g/kwh domestic Industry Agriculture electricity Surface water underground water 3 July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology July 8th and 9 th 2008
Binary Cooling System 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 4 July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology July 8th and 9 th 2008
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 5 July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology July 8th and 9 th 2008
The H2O/NH3 cycle 80% PN 20% PN The lowest pressure turbine stages in the vapor cycle and steam condenser are replaced with a NH3 cycle Threespecificcomponents : Condenser/boiler NH3 turbine Dry cooling system (Air cooled condenser)d for 450mbar 6 July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology July 8th and 9 th 2008
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 parameters high heat capacity (latent heat) High density of vapor at ambient temperature Cost and availability Risk and operation Tre (35 C) H20 R11 R12 NH3 Psat (bar) 0,056 1,49 8,46 13,5 V vap (m 3 /kg) 25,3 0,12 0,021 0,096 L=Hv-Hl (kj/kg) 2418 178 135 1123 EPRI ACT project used (on cooling technology) selected NH3 7 July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology July 8th and 9 th 2008
Additional advantages No water needs (dry cooling) Meet a general issue if limited cooling capacity on french rivers Larger choice for Plant constructions Extra power supply capability compared to steam cycle Expected gain of efficiency : 0,45% / C in winter (cold Temp.) Binary cycle Steam/water cycle Design point Power enhancement factor / ambient temperature 8 July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology July 8th and 9 th 2008
Historic of the studies at EDF 1970 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 9 July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology July 8th and 9 th 2008
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 10 July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology July 8th and 9 th 2008
Economic studies (ref. year 1989) 1/3 Economic 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 11 July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology July 8th and 9 th 2008
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 ) 12 July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology July 8th and 9 th 2008
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) 13 July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology July 8th and 9 th 2008
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» 14 July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology July 8th and 9 th 2008
Simulations (2/3) EPR plant EPR plant combined with Binary bottoming cycle Sensitivity to low steam pressure Sensitivity to exchangers pinch Sensitivity to ambiant temperature Comparison with wet or dry cooling 15 July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology July 8th and 9 th 2008
Simulations (3/3) EPR plant Power delivered / steam turbine backpressure Puissance fournie Débit NH3 1720 3890 1715 3880 Puissance (MW) 1710 1705 1700 1% débit (kg/s) 3870 3860 3850 3840 1695 3830 1690 0 100 200 300 400 500 600 700 800 Pression de coupure (mbar) 3820 0 100 200 300 400 500 600 700 800 pression de coupure (mbar) Power delivered / air temperature Puissance fournie Pression aval turbine BP puissance (MW) 1800 1700 1600 1500 1400 1300 1200-10 -5 0 5 10 15 20 25 30 35 Température éxterieure (C) Pression (bar) 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,1 0-10 -5 0 5 10 15 20 25 30 35 Température Exterieure (C) 16 July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology July 8th and 9 th 2008
Conclusion As 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 years ago) opportunity to engaged new pilot?? 17 July 8th and 9 th 2008 EPRI Workshop on Advanced Cooling Technology July 8th and 9 th 2008