312 r.j.basavaraj
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This document summarizes a presentation on chemical looping combustion (CLC) technology for power generation using coal synthesized gas. CLC uses oxygen carriers to transfer oxygen from air to fuel, allowing for inherent separation of carbon dioxide during combustion. The presentation outlines CLC technology, selection of oxygen carriers and reactor configurations reported in literature. It also provides analysis of a syngas-fueled CLC system layout and thermodynamic modeling of an optimized 800 MWth plant integrated with a supercritical steam cycle. The optimized design achieves higher efficiencies through increased steam temperatures.
![Heat balance of 800 MWth Syngas fueled CLC plant
Depleted Air [N2 =183.19 kg; O2 = 2.78 kg]
Q= 201.82 MW
Temperature (°C) = 1000
Depleted air flow rate (kg/s) = 185.97
Air reactor
T = 1000°C
QOx = 773.2 MW
ΔH = -ve
Exhaust [CO2 = 86.1 kg; H2O = 38.2 kg]
Q= 154.01 MW
Temperature (°C) = 900
Exhaust gas flow rate (kg/s) = 124.3
MeO (NiO : NiAl2O4)
QMeO= 402.85 MW
Temperature (°C) = 1000
MeO flow rate (kg/s) = 411.36
Q AR, Extract = 537.08 MW
Q FR, Extract = 58.30 MW
Fuel Reactor
T= 900°C
QRed = 26.8 MW
ΔH = -ve
QTotal, Extract = 595.38 MW
Preheated Air
T = 550°C
Q = 130.90 MW
Me (Ni : NiAl2O4)
QMe= 237.62 MW
Temperature (°C) = 900
Me flow rate (kg/s) = 358.49
Air-preheater
Preheated Fuel
T = 200°C
Q = 20.25 MW
Fuel-preheater
Q = 133.67 MW
Temperature (°C) = 798
Exhaust gas flow rate (kg/s) = 124.3
Q = 70.92 MW
Temperature (°C) = 390
Depleted air flow rate (kg/s) = 185.97
Air
Temperature (°C) = 30
Air flow rate (kg/s) = 238.85
Synthesis gas from coal
Temperature (°C) = 30
Fuel flow rate (kg/s) = 71.43
17](https://image.slidesharecdn.com/312r-131211044133-phpapp01/85/312-r-j-basavaraj-17-320.jpg)
![Optimised Heat Balance of syngas fueled 800 MWth CLC plant
Depleted Air [N2 =183.19 kg; O2 = 2.78 kg]
Q= 179.41 MW
Temperature (°C) = 900
Depleted air flow rate (kg/s) = 185.97
Air reactor
T = 900°C
QOx = 773.2 MW
ΔH = -ve
Preheated Air
T = 513°C
Q = 121.17 MW
MeO (NiO : NiAl2O4)
QMeO= 349.09 MW
Temperature (°C) = 900
MeO flow rate (kg/s) = 411.36
QAR, Extract = 606.45 MW
Exhaust [CO2 = 86.1 kg; H2O = 38.2 kg]
Q= 155.63 MW
Temperature (°C) = 908
Exhaust gas flow rate (kg/s) = 124.3
Fuel Reactor
T= 908°C
QRed = 26.8 MW
ΔH = -ve
Me (Ni : NiAl2O4)
QMe= 240.54 MW
Temperature (°C) = 908
Me flow rate (kg/s) = 358.49
Air-preheater
Preheated Fuel
T = 200°C
Q = 20.25 MW
Fuel-preheater
Q = 135.33 MW
Temperature (°C) = 806
Exhaust gas flow rate (kg/s) = 124.3
Q = 58.3 MW
Temperature (°C) = 327
Depleted air flow rate (kg/s) = 185.97
Air
Temperature (°C) = 30
Air flow rate (kg/s) = 238.85
Synthesis gas from coal
Temperature (°C) = 30
Fuel flow rate (kg/s) = 71.43
18](https://image.slidesharecdn.com/312r-131211044133-phpapp01/85/312-r-j-basavaraj-18-320.jpg)
312 r.j.basavaraj
- 1. ICAER 2013 Chemical-Looping Combustion Steam Cycle for Power Generation using Coal Synthesized Gas Paper ID 312 by R J Basavaraj , Sreenivas Jayanti Department of Chemical Engineering Indian Institute of Technology Madras Chennai -600 036, India
- 2. Outline of the presentation • Chemical-looping combustion (CLC) technology • Selection of oxygen carriers / support material, reactor configuration • Analysis of syngas CLC system and lay-out studies • Chemical-looping reactors, and heat exchangers, design • Current focus • Conclusions 2
- 3. Relevance of oxy-fuel combustion Rise in global warming -Increase in CO2 level, ~388 ppm in 2010, the highest for 650000 years; Surface temperature rise of 0.74+0.18 C over the 20th century Possibility of reduction of CO2 from concentric sources – coal-fired power plants, steel plants, cement kilns, steel industries, refineries .. Post combustion CO2 removal – Chemical looping combustion appears to offer advantages over combustion and solvent capture oxy-fuel 3
- 4. The countries that will be under water when the ice caps melt 4
- 5. Possible submergence of coastal areas of India due to melting of icecaps INDIA Image downloaded from the net around the time of announcement of a new nuclear power plant and energy price rises in the UK recently. http://i.imgur.com/lHfiCD5.jpg 5
- 6. Relevance of oxy-fuel combustion Rise in global warming -Increase in CO2 level, ~388 ppm in 2010, the highest for 650000 years; Surface temperature rise of 0.74+0.18 C over the 20th century Possibility of reduction of CO2 from concentric sources – coal-fired power plants, steel plants, cement kilns, steel industries, refineries .. Post combustion CO2 removal – Chemical looping combustion appears to offer advantages over combustion and solvent capture oxy-fuel 6
- 7. Chemical-looping combustion CO2, H2O N2 + unreacted O2 4MeO + CH4 (fuel) → 4Me + CO2 + 2H2O nMe + mAir → nMeO + Depleted air Air Reactor MeO Me Me Me Air O O Cm Hn Fuel Reactor Fuel Figure 1. Schematic of chemical looping combustion system Abbreviations “Me” and “MeO” will be used as general terms for reduced and oxygenated carrier respectively. Conventional heat of combustion, ΔH C = ΔH ox + ΔH Red 7
- 8. Chemical-looping combustion: Technical issues • • • • Oxygen carriers and support materials Reactor configuration Heat balance and optimization Thermodynamic analysis 8
- 9. Selection of O2 carriers for gaseous Fuels Cu2O/Cu Mn3O4/MnO Fe2O3/Fe3O4 1 NiO/Ni CoO/Co Active metal oxide*: • NiO, CuO, Fe2O3, CoO and Mn3O4 • NiO is chosen Inert Support**: • Al2O3, SiO2, TiO2 , ZrO2, NiAl2O4 and MgAl2O4 • NiAl2O4 is selected as a support Conversion of CH4 to CO2 • Reactivity of the oxygen carriers NiO > CuO > Mn2O3 > Fe2O3 0.8 Fe3O4/Fe0.947 O 0.6 0.4 Fe0.947O/Fe 0.2 0 800 1000 1200 1400 1600 T (K) Figure 3. Conversion of CH4 to CO2 as a function of temperature* *Hossain, M. M., & de Lasa, H. I, 2008, Chemical Engineering Science, 63(18), 4433–4451. **Ryu, H., et al., 2003, Korean J. Chem. Eng., 20(1), 157–162. 9
- 10. Reactor configurations being reported in the literature Place Configuration Fuel Reference Gaseous fuels Chalmer University of Technology, Sweden Interconnected CFB-BFB NG Institute of Carboquimica, Spain Interconnected BFB-BFB CH4 Linderholm et al. Int. J. of Green house Gas Control 2008;2:520-30. Garcia et al. Fuel 2007;86:1036-45. Xi' an Jiaotong University, China Interconnected CFB-BFB Coke oven gas Wang et al. Energ. Environ. Sci. 2010;3:1353-60 ALSTOM Power Boilers, France Interconnected CFB-BFB Mattisson et al. Energy Procedia 2009;1:1557-64. Korean Institute of Energy Research, Korea Interconnected CFB-BFB Technical university Vienna, Austria DCFB NG CH4, CO, H2 CH4, CO, H2 Coal, petcoke coal, biomass Berguerand N, Lyngfelt A. Fuel 2008;87:2713-26. Coal Ohio State University. NETL project NT005289 Coal Andrus H.E., Proc. 34th Int. Tech. Conf. on Clean Coal & Fuel Systems. Clearwater, Florida, USA; 2009. Adanez et al. Ind Eng Chem Res 2006;45:6075-80. Kolbitsch group. Int J Greenhouse Gas Control 2010;4:180-5. Solid fuels Chalmer University of Technology, Sweden Interconnected CFB-BFB Southeast university, China CFB-spouted bed Ohio State University, USA Interconnected moving bedentrained bed ALSTOM Windsor, Connecticut, USA Interconnected CFB-CFB CFB-Circulating Fluidized Bed BFB-Bubbling Fluidized Bed DCFB-Dual Circulating Fluidized Bed Shen et al. Energ Fuel 2009;23: 2498-505. 10
- 11. Progression of plant efficiency via advanced steam conditions and plant Designs TARGET 48 - 50 % 41%- 43% Up to 5400/1300/1325(psi/ F/ F) 38-41% 37-38 -Efficiency (net) HHV -Typical Steam Parameters Advanced USC 35-37% 4000/1110/1150(psi/ F/ F) 3480/1005/1050 (psi/ F/ F) 2400/1005/1005 167/540/540 Subcritical Technology Sliding Mature Pressure Supercritical Supercritical Material Development 4000/1075/1110 (psi/ F/ F) UltraSupercritical Commercial State of Art Supercritical Ni-based Materials T91 Advanced Austenitic Materials 1960 1980 2000 2010 Clean Coal Combustion: Meeting the Challenge of Environmental and Carbon Constraints by ALSTOM (USA), 2010 2020 11
- 12. Future research direction Korian Institute of Energy Research, 2010 12
- 13. Reactor configurations being reported in the recent literature Figure 4. Process diagram of the double loop circulating fluidized bed reactor system Bischi et al. 2011, International Journal of Greenhouse Gas Control, 5(3), 467-474. 13
- 14. Syngas fueled CLC plant lay-out studies Assumptions 1. 2. 3. Adiabatic reactors. Complete oxidation and reduction reactions. No reforming reaction's in fuel reactor and fuel is completely converted to CO2 and H2O. Composition* of coal synthesized gas Species Hydrogen Carbon monoxide Methane Formula H2 Mole % 45.7 CO 19.6 CH4 6.6 Carbon dioxide CO2 28.1 LHV 11.2 MJ/kg *Winslow, A.M., 1977, International symposium on combustion, 16, 503–513. 14
- 15. Reactions and operating variables Reaction of Ni/NiO on nickel-spinel (NiAl2O4) support* Air reactor: 2 Ni O2 ( g ) 2 NiO H1000oC 468 kJ/mol Fuel reactor: NiO CO( g ) Ni CO2 ( g ) H927oC 48 kJ/mol NiO H 2 ( g ) Ni H 2O( g ) H927oC 15 kJ/mol H927oC 133 kJ/mol 4 NiO CH 4 ( g ) 4 Ni 2 H 2O CO2 ( g ) Variables Operating Temperature : Air reactor (1000 C) and Fuel reactor (900 C) Reactor system operating pressure: 1atm Particle Composition by weight: 60% NiO + 40% NiAl2O4 Average Particle size: 200 micron; Sphericity: 0.99 *Adanez, J., et al., 2012, Progress in Energy and Combustion Science, 38(2), 215–282. 15
- 16. Reactors heat balance and supercritical steam cycle T 600 C 1 Power QAR, Extract Air reactor 600 C 600 C 3 5 Turbine QDepleted air QAir Cooled depleted air to atmosphere QOx . CP 4 2 Solids Gas Steam/water QMeO QMe . . 55 bar 14 bar Pump QRed QFuel QExhaust Fuel reactor Water removal and CO2 sequestration . 8 7 0.069 bar . 6 Figure 5a. CLC reactor system heat balance S Figure 5b. T-s diagram of supercritical, double reheat 240 bar/600/600/600 C steam cycle* Air reactor: Q Air in + Q Me + QOx = Q Depleted air + Q MeO + Q AR, Extract Fuel reactor: QFuel in + QMeO - QRed = QExhaust + QMe 16
- 17. Heat balance of 800 MWth Syngas fueled CLC plant Depleted Air [N2 =183.19 kg; O2 = 2.78 kg] Q= 201.82 MW Temperature (°C) = 1000 Depleted air flow rate (kg/s) = 185.97 Air reactor T = 1000°C QOx = 773.2 MW ΔH = -ve Exhaust [CO2 = 86.1 kg; H2O = 38.2 kg] Q= 154.01 MW Temperature (°C) = 900 Exhaust gas flow rate (kg/s) = 124.3 MeO (NiO : NiAl2O4) QMeO= 402.85 MW Temperature (°C) = 1000 MeO flow rate (kg/s) = 411.36 Q AR, Extract = 537.08 MW Q FR, Extract = 58.30 MW Fuel Reactor T= 900°C QRed = 26.8 MW ΔH = -ve QTotal, Extract = 595.38 MW Preheated Air T = 550°C Q = 130.90 MW Me (Ni : NiAl2O4) QMe= 237.62 MW Temperature (°C) = 900 Me flow rate (kg/s) = 358.49 Air-preheater Preheated Fuel T = 200°C Q = 20.25 MW Fuel-preheater Q = 133.67 MW Temperature (°C) = 798 Exhaust gas flow rate (kg/s) = 124.3 Q = 70.92 MW Temperature (°C) = 390 Depleted air flow rate (kg/s) = 185.97 Air Temperature (°C) = 30 Air flow rate (kg/s) = 238.85 Synthesis gas from coal Temperature (°C) = 30 Fuel flow rate (kg/s) = 71.43 17
- 18. Optimised Heat Balance of syngas fueled 800 MWth CLC plant Depleted Air [N2 =183.19 kg; O2 = 2.78 kg] Q= 179.41 MW Temperature (°C) = 900 Depleted air flow rate (kg/s) = 185.97 Air reactor T = 900°C QOx = 773.2 MW ΔH = -ve Preheated Air T = 513°C Q = 121.17 MW MeO (NiO : NiAl2O4) QMeO= 349.09 MW Temperature (°C) = 900 MeO flow rate (kg/s) = 411.36 QAR, Extract = 606.45 MW Exhaust [CO2 = 86.1 kg; H2O = 38.2 kg] Q= 155.63 MW Temperature (°C) = 908 Exhaust gas flow rate (kg/s) = 124.3 Fuel Reactor T= 908°C QRed = 26.8 MW ΔH = -ve Me (Ni : NiAl2O4) QMe= 240.54 MW Temperature (°C) = 908 Me flow rate (kg/s) = 358.49 Air-preheater Preheated Fuel T = 200°C Q = 20.25 MW Fuel-preheater Q = 135.33 MW Temperature (°C) = 806 Exhaust gas flow rate (kg/s) = 124.3 Q = 58.3 MW Temperature (°C) = 327 Depleted air flow rate (kg/s) = 185.97 Air Temperature (°C) = 30 Air flow rate (kg/s) = 238.85 Synthesis gas from coal Temperature (°C) = 30 Fuel flow rate (kg/s) = 71.43 18
- 19. 19 Thermodynamic analysis of CLC power E1 plant and supercritical steam cycle A3 S5 S6 Stream P, bar T, °C m, kg/s h, kJ/kg A1 1.0132 30 238.85 0 600 C 600238.85 C507.33 C 600 A2 1.0132 513 M1 1 3 5 HP A3 1.0132 900 185.97 964.68 Stream A4 1.0132 327 185.97 313.46 A- Air S7 A5 1.0132 70 185.97 41.54 E- Exhaust S8 F1 1.0132 30 71.43 0 HE2 F- Fuel F2 1.0132 200 71.43 283.51 MP M- Metal/Metal oxide M2 E1 1.0132 908 124.30 1252.03 S- Water/steam CP 4 E2 1.0132 807 124.30 1088.78 HP- High pressure S9 2 S10 E3 1.0132bar 80 124.30 59.09 MP- Medium pressure 55 HE3 LP- Low pressure E4 1.0132 40 124.30 11.67 LP 14 E5 1.05 bar 40 38.20 18.73 F2 E6 1.05 40 86.09 8.54 S11 E7 110 35 86.09 4.26 A2 S1 243.12 39 116.73 184.82 S2 243.12 252 116.73 1096.48 E2 Air Fuel 8 0.069 bar S3 243.12 39 46.126 184.82 preheater preheater 7 S4 243.12 252 46.12 1096.48 S5 240 252 162.85 1096.48 S F1 A4 A1 S6 240 600 162.85 3502.91 Condensate Condensate S13 preheater 2 preheater 1 S7 55 305 162.85 2922.83 S4 S1 S12 S8 55 600 162.85 3662.80 S3 Pump 2 Pump 1 S9 14 332 162.85 3117.56 S2 E3 Flue gas conditioner S10 14 600 162.85 3695.40 E4 S11 0.069 39 162.85 2573.72 E5 A5 CP-Critical point Four stage compressor with E6 S12 0.069 39 46.12 2573.72 intercooling S13 0.069 39 116.73 2573.72 E7 M1 1.01325 900 411.36 848.61 M2 1.01325 908 358.49 PP. 40-71. *El-Wakil.; Mohamed, M. Power Plant Technology, New York, 2010, 670.97 HE1 T Fuel reactor Air reactor . .. . . T-s diagram of supercritical,double reheat 240 bar/600/600/600 C steam cycle*
- 20. CLC power plant lay-out configuration CFB- Circulating Fluidized Bed BFB- Bubbling Fluidized Bed Figure 7. General arrangement for gaseous chemical-looping combustion. 20
- 21. Possible carbon capture and sequestration options* *Intergovernmental Panel on Climate Change (IPCC)-2005 21
- 22. Overall energy analysis CLC steam cycle power plant: 240 bar/600/600/600 C Fuel AR Temperature, C FR Temperature, C AR cooling heat capacity, MWth FR cooling heat capacity, MWth HP turbine, MWe MP turbine, MWe LP turbine, MWe Total production, MWe CO2 compression, MWe Water pumping, MWe Total power consumption, MWe Total useful output, MWe Thermal input, MWth Gross efficiency Net efficiency Syngas 1000 900 537 58 94 88 182 365 31 5 36 329 800 45.74 41.22 Revised Syngas 900 908 606 0 94 88 182 365 31 5 36 329 800 45.74 41.22 AR: Air reactor, FR: Fuel reactor, HP: High pressure , MP: Medium pressure and LP: Low pressure 22
- 23. Chemical-looping combustion system: layout design Issues • Chemical-looping reactor design PFR Factors Particle Residence Time Fluidization Regimes in Reactor System Reaction Kinetics • Heat transfer area 23
- 24. Chemical-looping reactor Design (Cont…) 1 Fuel flow (kg/s) 2 Air flow (kg/s) 3 Area of reactor (Air /Fuel) 4 Solids holdup in the CFB air reactor (kg) 5 Solids holdup in BFB fuel reactor (kg) 6 Average solid fraction in CFB air reactor 7 Average solid residence time t = solids holdup/solids flow rate *Naqvi R. 2006, Analysis of Natural Gas-Fired Power Cycles with CLC for CO2 Capture. Doctoral Theses: NUST. #Kunii D, Levenspiel O. 1991, Fluidization Engineering. 2nd Ed. Washington: Butterworth-Heinemann. 24
- 25. (Cont…) Chemical-looping reactor design BFB Fuel Reactor Gas flow (kg/s) 71.43 Gas density at reactor temperature (kg/m3) 0.3848 Gas velocity (m/s) 2.10 Oxidation area (m2) 87.14 Diameter of column (m) 10.54 Length of column (m) 1.50 Density of metal (kg/m3) 2420 Average solid fraction 0.40 Hold up mass (kg) 126533 Mass flow of metal/metal oxide at reactor exit (kg/s) 358 Average solids residence time (s) 353 Parameter CFB Air Reactor 238.85 0.3011 4.7 170.31 14.73 45 2420 0.0011 20669 411.36 50 25
- 26. Fluidization regimes† dp, m Air reactor dp* u, m/s u* 0.0002 2.91 2.01 4.7 dp, m Fuel reactor dp* u, m/s u* 0.0002 4.23 1.06 2.1 Circulating fluidized bed air reactor 10 1 10-1 Bubbling fuel reactor 10-2 Syngas Lay-out AR Syngas Lay-out FR 10-3 1 10 102 † Kunii D, Levenspiel O. 1991, Fluidization Engineering. 2nd Ed. Washington: Butterworth-Heinemann. 26
- 27. Heat transfer area 1 Fluidized bed to surface heat transfer coefficient (neglecting radiation effect) is given by the Zabrodsky’sEquation* (W/m2K) 2 Botterill Recommendationfor effective heat transfer* (W/m2K) 3 Heat transfer co-efficient on fluid side ( W/m2K) 4 Overall heat transfer co-efficient (W/m2K) 5 Heat exchanger surface area (m2) Heat exchanger Q, kW U, kW/m2K ∆TLMTD, K A , m2 Air-preheater 121173 0.110 340 3240 Fuel-preheater 20250 0.112 742 248 Embedded Heat exchanger 1 391885 0.216 452 4015 Embedded Heat exchanger 2 120504 0.166 431 1685 Embedded Heat exchanger 3 94101 0.177 420 1266 *Simeon NO. Fluidized Bed Combustion. Basel: Eastern Hemisphere; 2004. 27
- 28. Current focus • Studies are in progress to develop a Dual-fuel CLC power plant layout for natural gas as well as syngas without affecting steam side load. • Catalyst NiO:NiAl2O4 (60:40 by mass) is prepared. Experimental studies on fuel reactivity. Electric coil heating arrangement Fluidized bed reactor Moisture Trap Gas Analyser: O2, N2 Stack Gas Analyser: H2, CH4, CO, CO2 CH4 CO Air 28
- 29. Conclusions • From the energy balance and thermodynamic analysis of syngas fuelled 800 MWth CLC system, a power plant layout is made. • Thermodynamic calculations show that CLC-steam cycle is capable of achieving overall net cycle efficiency up to 41.22%. This efficiency includes 100% carbon capture. • The aerodynamics, particles residence time of the CLC reactor system has been studied. Enough heat transfer area is provided in heat exchanger so that required amount of heat transfer to takes place. • The proposed lay-out is designed in such a way that CLC plant operates at atmospheric pressure on the fuel side and generates supercritical steam (240 bar/600/600/600oC) on the steam side to run a steam turbine while maintaining a high overall thermal efficiency and a net electrical output of 330 MWe. 29
- 30. THANK YOU 30
- 31. Geological Storage of CO2 • IPCC (2005) Potential storage sites spread all over the world 31
Editor's Notes
- #13: Future Research Direction