Efficient and sustainable power plants : emerging technology options an academic perspective

Transcription

1 Efficient and sustainable power plants : emerging technology options an academic perspective Prof.dr.ir. Adrian Verkooijen Faculty of Mechanical, maritime and Materials Engineering Laboratory for Energy Technology symposium on "Solid Oxide Fuel Cells for Next Generation Power Plants Delft, 23 June

2 Changing environment: Growing Per world capita population income (PPP) Economic growth Growing prosperity Increasing per capita energy consumption Environmental concerns Global: CO 2 Local: SOx, NOx, Rox Changing primary energy sources: More variable renewable sources Reliability of oil and gas producers Rising prices fossil energy Integrated Networks and Markets 2

3 Challenges for Power Industry Affordable energy supply with stable prices Low emissions Security of supply 3

4 Low electricity prices Low capital costs: Low investment costs, long economical life time Low O&M Low maintenance costs Low fuel costs High conversion efficiency Cheap fuel, low quality coal, lignite High market value High power factors High flexibility: large turn down ratio-fast ramp updown 4

5 Low emissions High energy conversion efficiency Fuel switch: coal natural gas, LNG, biomass Carbon Capture and Storage ( )Combined Heat and Power and district heating Implement and improve de-sox, de-nox Attention to Hg and other toxic metals emissions 5

6 Security of supply Diversification of primary energy sources More local, renewable energy sources Low unforeseen unavailability Reliable networks 6

7 Future gas supply to Europe? NORWAY bcm bcm bcm bcm RUSSIA and Central Asia AZERB TURKMENISTAN ALGERIA LIBYA EGYPT IRAQ 35 IRAN QATAR/ UAE/ OMAN/ YEMEN

8 EU energy priorities: Energy for citizens and businesses must be: SECURE SAFE AFFORDABLE 8

9 EU emission commitments 20% CO 2 emission reduction 30% reduction in case of global consensus 20% renewable energy sources 20% energy efficiency increase 9

10 Pillar for EU development: SET plan Wind Solar Biomass Carbon Capture and Storage Nuclear fission Fuel cells & hydrogen Energy efficiency (demand side) 10

11 Industry response: VGB study: "Calculation of CO 2 avoidance potential by modernizing power plants in the EU 27 until 2020 Power demand will grow 2005: 3275 TWh 2020: 3728 TWh Installed capacity renewables: 295 GW To meet target -20% CO 2 emission 175 GW old fossil power plants must be replaced by technology with highest efficiency Atom Ausstieg in Germany ( and other countries) will increase this number 11

12 New capacity 12

13 Netherlands Large scale projects ~13 GWe natural gas coal biomass

14 Power plants Fossil fired power plants Renewable energy power plants Nuclear power plants Emerging technologies, fusion.. 14

15 Fossil fired power plants Combustion turbines Combined cycle gas turbine Pulverized coal plants Integrated gasification combined cycle Combined heat and power District heating 15

16 Combustion turbines Higher efficiency by higher Turbine Inlet Temperature Materials problem Cycle improvements Sequential combustion ( reheat ) Intercooled compressors Recuperative heat exchangers Efficiency improvements + increased complexity + increased investment costs 16

17 Combustion Turbines New materials for turbine rotor: austenitic steel and blades: Ti n+1 AlC n 17

18 Properties of Ti n+1 AlC n Strong at high temperatures Oxidation resistant High thermal and electrical conductivity Thermal Shock resistant High fracture toughness damage tolerant Easy to machine Promising material for a variety of high temperature applications Crack healing ability at operating temperatures

19 Oxidation induced crack-healing in Ti 3 AlC 2 proof of principle Selective oxidation of Al 1100 o C in air Healing product has similar properties as matrix

20 Combustion turbine Better Thermal Barrier Coatings Improve lifetime of TBC coating systems Effect of high water vapor pressures Self healing TBC 20

21 Improved lifetime TBC The crack pattern evolves at the BC TGO interface is larger for larger interface imperfections is virtually absent for very small imperfections location and orientation agrees with experiments

22 Crack-healing mechanism in a thermal barrier coating (TBC) with encapsulated Mo-Si based particles TBC system comprises a nickel based superalloy substrate with a MCrAlY bond coating (BC) which produces a thermally grown oxide (TGO) during service and the modified yttria stabilized zirconia (TBC)

23 Combustion turbines More pressure levels in HRSG Super critical steam conditions 23

24 Coal fired power plants Improved efficiency Higher steam conditions 400 bar, 700 o C Double reheat 24

25 400 bar 700 o C 50 bar Hyper critical steam generator 2 bar

26 Material for the next generation of power plants Speicher, Stüttgart 08 September

27 Critical Raw Materials for the EU Report of the Ad-hoc Working Group on defining critical raw materials, June 2010 Risk assessment based on supply risk and economic relevance Nickel-based superalloys contain wt.% Cobalt Cobalt (Co) is a critical raw material for the EU 08 September

28 Current state-of-the-art: Ferritic steel Taneike, Nature (2003) Critical for EU Creep-resistant Cr-W-steel up-to 650 C => Not sufficient Key: Microstructure consisting of ferrite and precipitates 08 September

29 New materials for next generation source: Siemens

30 Current state-of-the-art: Nickelbased superalloy Advantage: Good high-temperature properties Disadvantage: Expensive Critical element: Co Speicher, Stuttgart 08 September

31 Composition Inconel 617 % Ni 54 Cr 22 Co 12 Mo 10 Al 1 Ti 0,5 C 0,1 Strategic materials

32 Challenge: Design of new steel microstructures with ubiquitous elements Offerman, TU Delft 08 September

33 Other challenges for coal fired PP Increase fraction biomass for co-firing Corrosion, fouling, de-nox catalyst deactivation, pneumatic transport of coal-biomass mixtures Pre drying of high moisture fuels Ash handling of low grade coals Improve isentropic efficiency of steam turbines, blade design Lower exit losses 33

34 Post combustion decarbonisation

35 Typical Amine absorption process

36 Scale up of absorption column Packing -> pressure drop -> energy loss

37 Open spray column

38 Low pressure drop High mixing -> low absorption efficiency

39 Horizontal absorber, less mixing CO 2 rich flue gas CO 2 rich flue gas 39

40 IGCC challenges Develop more reliable, low cost IGCC technology Increase fraction biomass for co-gasification Integrate water gas shift reactor and CO 2 removal Develop combustion turbines for H 2 rich gas with high H 2 O pressures Develop H 2 purification technology for alternative applications 40

41 Pre combustion carbon capture: IGCC

42 Exergy losses relative to fuel

43 Water gas shift reactor CO 0 H O 2 CO H 41kJ / 298 H mol High Temp Catalyst <20 ppm H 2 S Low Temp Catalyst <0,1 ppm H 2 S Sour shift Catalyst <1000 ppm H 2 S 2 2

44 Advanced Water-gas-shift Reactor Section Water R1 R2 R3 R4 IP Steam Shifted Syngas Split fraction 1 Syngas S Split fraction 2 Split fraction 3 Split fraction 4 Bypass Syngas Bypass

45 Results: Advanced Clean WGS (dry-fed IGCC) 100% 80% CO-conversion Overall Steam/CO = 1.4 Overall CO Conversion [-] 60% 40% 20% 4 HT-WGS Reactors (Staged) HT- & LT-WGS Reactor (Seq.) 0% IP Steam Consumption [kg/s]

46 Efficiency penalties at 90% COconversion Efficiency (LHV) Conventional WGS Efficiency penalty steam req. Total efficiency penalty Advanced WGS Efficiency penalty steam req. Total efficiency penalty Dry-fed IGCC & Clean WGS 47.4% 11.5%pt. 14.7%pt. 4.0%pt. 9.4%pt.

47 What about Fuel Cells? Valuable for very integrated conversion systems Integration of : Gasification, gas cleaning, SOFC, combustion turbine -Combined Heat and Power for domestic use: PEM very high overall energy efficiency ( > 90%) 47

48 Large scale Power Plant Electric power: 30 MWe Pressurized air CFB gasification o C, 18 bar High Temperature gas cleaning, o C, 18 bar Solid oxide Fuel Cell 900 o C, 8 bar Combustion Turbine tit 1100 o C, pressure ratio 8 48 R. Toonssen, 2010

49 Large scale PP, 30 MWe, flow diagram 49 R. Toonssen, 2010

50 Exergy flow diagram for biomass feed 50 R. Toonssen, 2010

51 Conclusions: Fossil fired power plants must and will contribute to affordable and safe electricity supply Technological development will, step by step, improve the sustainability Fuel cells have interesting potentials in the small and medium size power plants 51