Slide 1

SECTIE ENERGIE EN INDUSTRIE The crucial integration of power systems; Combining fossil and sustainable energy using fuel cells Kas Hemmes Lunchlezing 21 februari 2006 ; TU Delft SECTIE ENERGIE EN INDUSTRIE Slide 2 Outline Introduction Classification of Energy systems MSMP Energy systems (Energy Hubs & Modeling and optimization methodology) Examples Conclusions Acknowledgements Slide 3 SECTIE ENERGIE EN INDUSTRIE Introduction: Energy System YDTCT system boundary i,in (x,t) j,out (x,t) C S loss (x,t) Slide 4 SECTIE ENERGIE EN INDUSTRIE Introduction: Storage often necessary YDTCT S Yield & Demand Y(x,t) D(x,t) Slide 5 SECTIE ENERGIE EN INDUSTRIE 1 Classification of energy system 2 3 Linear energy system Co-generation system Tri-generation system Slide 6 SECTIE ENERGIE EN INDUSTRIE Linear energy system 1 2 3 F R N E-net Slide 7 SECTIE ENERGIE EN INDUSTRIE Input combinations of Fossil and Renewables Biomass Co-firing F R E-net Bio-ethanol Bio-diesel mix F R Transport Slide 8 SECTIE ENERGIE EN INDUSTRIE Multisource-multiproduct MSMP-systems a b c Etc. d Slide 9 SECTIE ENERGIE EN INDUSTRIE Example : simple CHP energy hub c Slide 10 SECTIE ENERGIE EN INDUSTRIE energy hub Slide 11 SECTIE ENERGIE EN INDUSTRIE Power Flow Coupling Slide 12 SECTIE ENERGIE EN INDUSTRIE Relation between coupling matrix C and energy hub L = C. P Slide 13 SECTIE ENERGIE EN INDUSTRIE Optimization How much of which input should be consumed in order to meet the load demand in an optimal manner ? (due to a certain optimality criterion, e.g. energy cost or emissions) Slide 14 SECTIE ENERGIE EN INDUSTRIE Why new energy systems? What to optimize? Present systems suffer from inefficiencies 1.Conversion efficiency < 100% 2.Mismatch between Supply & Demand in time and space 3.Transport losses 4.Not 100% eXergy efficient (minimum entropy production) 5.Not used 100% of the time 6.Not 100% Renewable/sustainable 7.Not flexible, not 100% reliable 8.But also mixing entropy: N2 in Natural Gas; N2 in CO2 off-gas etc. 9.and Institutional, Economic Slide 15 SECTIE ENERGIE EN INDUSTRIE Integration of Fuel Cells in a Nitrogen - Natural Gas mixing station IR-FCFCAir - SEP heat air N2N2 O2O2 NG NG/N 2 /(H 2 ) H2H2 E - power H2H2 Low T heat E - power Slide 16 SECTIE ENERGIE EN INDUSTRIE Example: FC replacing N 2 /O 2 seperation unit in N 2 -NG mixing station IR-FCLow-T FC air N2N2 NG NG/N2/(H 2 ) H2H2 E - power N2N2 Low T heat The system is producing E-power instead of consuming it !! Slide 17 SECTIE ENERGIE EN INDUSTRIE DOE goal for the 21 st century fuel cell (higher efficiencies) 40 90 80 70 60 50 Thermodynamic efficiency, % H std Chart source: NETL, Nov. 1999 C+O 2 = CO 2 (DCC) CH x pyro +DCC Westinghouse tube SOFC Fuel-cell/turbine hybrid technologies Combined cycle Conventional Steam plants Slide 18 SECTIE ENERGIE EN INDUSTRIE Slide 19 Slide 20 Slide 21 Precombustion solid-gas separation of Carbon in a MSMP system Thermal decomposition F (CxHy) R (Solar) or Nuclear C H2H2 Slide 22 SECTIE ENERGIE EN INDUSTRIE Slide 23 Thermodynamic advantages of Direct Carbon Conversion Table 3 Order of magnitude comparison between the electrochemical conversion efficiencies of C, H 2 and CH 4 at 700 o C (Cooper, J. F. et al 2000) Fuel fc Nernst loss irr tot C1.0 0.8 H2H2 0.70.8 0.45 CH 4 0.890.8 0.57 Slide 24 SECTIE ENERGIE EN INDUSTRIE Electrochemical gasification in a Direct Carbon Fuel Cell 2C + O 2 ==> 2CO S>0 H SECTIE ENERGIE EN INDUSTRIE A Fuel Cell that produces hydrogen and converts heat into power ? CO + H 2 O ==> H 2 + CO 2 DCFC C Q (solar) Power Syngas C+O 2 = CO Slide 27 SECTIE ENERGIE EN INDUSTRIE Looking for ways to use the full exergetic quality of solid fuel !! Solid fuels become increasingly more important (security of supply). Coal because it is cheap and abundant. Biomass because it is CO 2 neutral. Waste. Also liquids are closer to solids than to gases in terms of their exergy value. Slide 28 SECTIE ENERGIE EN INDUSTRIE Countries with large potential for Solar and Biomass can become the energy producing countries of the future. Fuel cell technology Solar Biomass Slide 29 SECTIE ENERGIE EN INDUSTRIE Example of trigeneration: H 2 and power co-production using an internal reforming fuel cell. IR-FC NG E - power CO / H 2 heat Slide 30 SECTIE ENERGIE EN INDUSTRIE MCFC - Hot Module Slide 31 SECTIE ENERGIE EN INDUSTRIE MCFC Hot Module Slide 32 SECTIE ENERGIE EN INDUSTRIE Co-production Co-production of hydrogen and power from NG in an Internally reforming fuel cell (IR FC) is worked out by flow sheet calculations on an Internal Reforming Solid Oxide Fuel Cell (IR-SOFC) system. It is shown that the system can operate in a wide range of fuel utilization values from 95% i.e. normal fuel cell operation mode up to 60% and lower corresponding to hydrogen production mode. Slide 33 SECTIE ENERGIE EN INDUSTRIE Internal Reforming - SOFC system flowsheet Slide 34 SECTIE ENERGIE EN INDUSTRIE Mode 1 High efficiency mode First we kept the input flow rate of NG constant. The fuel utilization is now decreased by decreasing the current density. 1 input (natural gas input is kept constant at 2000 kW) 3 outputs vs Fuel Utilization Electric Power H 2 & CO (Waste) heat Efficiency vs Fuel Utilization Slide 35 SECTIE ENERGIE EN INDUSTRIE Mode 1 High efficiency mode Slide 36 SECTIE ENERGIE EN INDUSTRIE Fuel cell theory and modeling OCV = Open Cell Voltage = 100 220 mV u f = fuel utilisation i = current density r = specific resistance Slide 37 SECTIE ENERGIE EN INDUSTRIE Conventional Solution for dealing with fluctuating renewable energy sources essentially is a complex storage device in a linear energy system. E - power Storage Slide 38 SECTIE ENERGIE EN INDUSTRIE Conventional Solution for dealing with fluctuating renewable energy sources Electrolyser E - power heat H 2 FC O2O2 H2OH2O H2OH2O E - power Storage Slide 39 SECTIE ENERGIE EN INDUSTRIE Example: Integration of a H 2 - power co-production FC with fluctuating renewable energy sources. IR-FC air N2N2 NG Optional (NG/N 2 ) H2H2 E - power H 2 heat Slide 40 SECTIE ENERGIE EN INDUSTRIE Energy hub model of previous example IR-FC NG E - power CO / H 2 heat E - power Slide 41 SECTIE ENERGIE EN INDUSTRIE Remarks on Gasgestookte windenergie No storage of H2 needed. Instead the storage capacity of NG is used North sea provides NG and Wind !! Slide 42 SECTIE ENERGIE EN INDUSTRIE Conclusions System thinking!! Identify "inefficiencies" An integration between Fossil and Renewable is possible and may be crucial in meeting our needs without sacrificing those of future generations. New definitions of efficiency and green energy in MSMP systems needed Slide 43 SECTIE ENERGIE EN INDUSTRIE Acknowledgments TU Delft : Anish Patil, Theo + Nico Woudstra (Cycle Tempo flowsheet calculations) ETH : Martin Geidle (MSMP concept & calculations)