Thermodynamic Assessment of the Calcium- Looping Process Applied to a Lignite-Fired Power Plant

Transcription

1 Otto-Berndt-Straße Darmstadt / Germany Phone: Thermodynamic Assessment of the Calcium- Looping Process Applied to a Lignite-Fired Power Plant 9 th Trondheim Conference on CO 2 Capture, Transport and Storage (TCCS-9), June 12-14, Trondheim, Norway M. Haaf*, M. Helbig, J. Hilz, A. Stroh, J. Ströhle, B. Epple Institute for, Technische Universität Darmstadt, Otto-Berndt-Str. 2, DE Darmstadt, Germany 1

2 Agenda Introduction Methodology Results Conclusion 2

3 Introduction Motivation CO 2 emissions by sector Electricity generation by fuel Application of the Calcium Looping (CL) Process for Post Combustion CO 2 capture > 90 % CO 2 capture feasible Utilization of excess heat at high T ( highly efficient steam cycle) Noticeable increase of thermal and electrical power capacity International Energy Agency (IEA) STATISTICS, CO 2 Emissions From Fuel Combustion Highlights (2015) Edition 3

4 Introduction Process Scheme Air FG* Eta (HP + CCL + compr.) < Eta (HP + CCL) < Eta HP CO 2 Compression P el P el CO 2 P el Power Plant FG FG CL Process Heat Lignite dry 2 nd Power cycle Pre- Drying Lignite ar O 2 ASU P el Lignite ar Eta HP Eta CCL * CO 2 depleted flue gas 4

5 Methodology Calcium Looping Model Q1 Carbonator (650 C) FG Q2 CO 2 -depleted FG Purge Q3 CO 2 -product Recirculation Calciner (900 C) Oxygen Fuel Make-up ASPEN PLUS TM based process simulation flowsheet environment Empirical 1-D sub models CFB hydrodynamics Sorbent activity Carbonation reaction Calcination reaction CaO (s) + CO 2(g) ΔH CaCO3(s) ΔH 25K = kj/mol Validated by experimental data achieved during long term pilot tests in 1 MW th scale 5

6 Methodology CO 2 compression Q4 Q5 Q6 Stage 1 Stage 2 Stage 3 Stage 4 CO 2 -rich stream compressed CO 2 Compression of the CO 2 product stream for transportation / utilization Supercritical state (110 bar / 28 C) Heat utilization (Q4, Q5, Q6) European Benchmarking Task Force (EBTF), European Best Practice Guideline for Assessment of CO 2 Capture Technologies,

7 Methodology Heat Recovery Calcium Looping Power Cycle Q2, Q3 RH HP-T IP-T LP-T G Q2, Q3 SH Q1 EVA Q2, Q3 Q2, Q3 Q4, Q5, Q6 COND ECO HP-P LP-PH FW-P 7

8 Results CL Process Model Validation CFB hydrodynamics / solid distribution Empirical solid phase distribution Lean phase / dense phase reactor height [m] W s,carb : 804 kg/m² sim exp (a) H d : 1.0 m Δp [mbar] W s,carb : 550 kg/m² (c) H d : 0.4 m Δp [mbar] 8

9 Results CL Process Model Validation Reactor efficiencies Sorbent composition at carbonator inlet / outlet (1) (2) (3) (4) E Carb [%] E Carb exp E Calc exp E carb sim E Calc sim E Calc [%] sorbent composition [w.%] CaCO 3 impurities CaO operation point [-] inlet outlet inlet outlet inlet outlet inlet outlet Left hand columns: experiment Right hand columns: simulation Impurities: CaSO 4 / Ash 9

10 Results Full-scale Flue gas*: m FG : 947 kg/s y CO2 : 2.94 v/v% CO 2 -Product m CO2 : 337 kg/s y CO2 : >96 v/v% Flue gas: m FG : 1,118 kg/s y CO2 : v/v% Loaded Sorbent: m : 2,453 kg/s x CaCO3 : 15.7 m/m% Oxygen: m O2 : kg/s y O2 : 95 v/v% Host Plant Carbonator Calciner Lean Sorbent m : 2,301 kg/s x CaCO3 : ~0 m/m% Lignite ar : m: 140 kg/s Make-up: m: 27.8 kg/s Purge m : 18.2 kg/s E carb : 79 %, E tot : 88% F 0 /F R : 0.01, F R /F CO2 : 7.2, X Carb :

11 Results Full-scale HP+CL+Compr. eta: % HP+CL eta: % Thermal input Power (gross) Power (Auxiliary) HP eta % Thermal input [MW th ], Pow er[mw e ] 11

12 Q Results Sensitivity Study Efficiency drop 3.6 no HX CO 2 -depleted FG CO 2 -product Recirculation K 50 K Carbonator (650 C) Purge Calciner (900 C) Fuel Make-up ƞ loss,ccl [%-points] FG Oxygen O 2 calciner in [mol.%] 12

13 Conclusion Detailed modelling of the CL Process attached to a lignite-fired power plant (CL-system; heat recovery; lignite pre-drying; CO 2 -compression) Efficiency drop in the base case 3.26 %points / 7.63 %points (including compression) Effect of oxygen concentration at calciner inlet: %points Effect of solid-solid HX: %points 13

14 Outlook Extending of model validation including 1,000 hours of CL operation Particle attrition and entrainment Dynamic plant operation (start-up; shut-down) and part load of the host plant Steam effect, deactivation of the sorbent 14

15 Acknowledgement LISA 2 funded by BMWi and industrial partners SCARLET funded by EU FP7 15