Development and Validation of a Process. Capture CO 2

Transcription

1 Development and Validation of a Process Simulator for Chilled Ammonia Process to Capture CO 2 Rameshwar Hiwale International Conference on Energy Process Engineering June 20-22, 2011

2 Outline Overview of Model Development VLE/Thermo-Physical Properties Regression Overall Flowsheet CAP Thermodynamic Modeling Model Validation using experimental field data Conclusion and future work International Conference on Energy Process Engineering June 2011 P 2

3 Technology scale-up road map Test Rigs Industrial Pilots Validation Pilots 2015 Large-scale demonstration Commercial by 2015 Alstom Vaxjö We Energies Pleasant Sweden Prairie 025MWth 0.25 USA - 5MWth MWth, Coal EoN Karlshamn Sweden - 5 MWth, Oil AEP Mountaineer USA - 58 MWth, Coal TCM Mongstad Norway - 40 MWth, Gas AEP Mountaineer US - >200 MWe, Coal Turceni Feasability Romania - >200 MWe, Lignite Selected by US DOE to receive CCPI Round 3 funding Roadmap to commercialization International Conference on Energy Process Engineering June 2011 P 3 Tests completed In operation Under construction Targeted

4 Chilled Ammonia Process (CAP) Principle Cooled flue gas is treated with ammonium carbonate in solution, which reacts with CO 2 to form ammonium bicarbonate Raising the temperatures reverses the above reactions releasing pressurized CO 2 Advantages Energy-efficient capture of CO 2 High CO 2 purity Tolerant to oxygen and flue gas impurities Stable reagent, no degradation possible, no emission of trace contaminants Low-cost, globally available reagent Low cost and market stable reagent with potentially salable byproduct (ammonium sulfate). Source: Alstom A new technology with high h potential ti! International Conference on Energy Process Engineering June 2011 P 4

5 We Energies field pilot Proof of Concept Objectives met: 90% CO 2 capture efficiency CO 2 Product Quality >99.5% Sustained regeneration at high pressure NH 3 in residual flue gas < 10 ppm No solvent degradation Heat integration opportunities identified Mechanical inspection confirmed materials selection Sustained operation through power plant transients CO 2 Field Pilot at Pleasant Prairie Basic concept proven International Conference on Energy Process Engineering June 2011 P 5

6 Mountaineer process validation facility (PVF) Proof of Concept Objectives met: 75-85% CO 2 capture efficiency (Design - 75%) CO 2 Product Quality >99.9% NH 3 in residual flue gas < 10 ppm Minimal solvent make-up Lessons learnt being incorporated as the development program continues Sustained operation through power plant transients Sequestration CO 2 Field Pilot at AEP Mountaineer Basic concept proven International Conference on Energy Process Engineering June 2011 P 6

7 Process model development for CAP Aspen Plus VLE and Thermodynamic Property parameters regressed to fit laboratory data. - VLE : Binary/ Ternary Parameters Low to High Molarity Full Range of Process Temperatures - Heat Capacities, Speciation, Viscosity, Density, and Surface Tension Validation of CAP Model with regressed parameters done by comparison against reconciled field data from Vaxjo (Sweden), WE Energies (USA), EON Karlshamn (Sweden) and AEP Mountaineer (USA). Model being employed: - Conducting optimization and sensitivity studies - Predictive tool for setting operating objectives - Process Design for FEED studies International Conference on Energy Process Engineering June 2011 P 7

8 Process model development VLE/ thermo-physical properties regression PCO2 Ammonia Solution Molarity :Higher Molarity Experimental Estimated Aspen with ungressed Parameters Mole Fraction of CO2 Partial Pressure of CO 2 as function of CO 2 loading at higher molarity and low temperature Regressed model Unregressed model VLE conditions accurately match literature data International Conference on Energy Process Engineering June 2011 P 8

9 Process model development VLE/ thermo-physical properties regression Ammonia Solution Molarity : Low Molarity Experimental 2.5 Estimated Aspen Unregressed Parameters Regressed model 2.0 PCO Mole Fraction of CO2 Unregressed model Partial Pressure of CO 2 as function of CO 2 loading at lower molarity and high temperature Regressed model accurately match literature data International Conference on Energy Process Engineering June 2011 P 9

10 Process model development Heat capacity regression Cp Liquid Heat Capacity Experimental 4.2 Estimated Aspen Unregressed Parameters Temperature Regressed model Unregressed essed model Ammonia-water liquid id heat capacity Improved heat capacities from regressed model International Conference on Energy Process Engineering June 2011 P 10

11 Overall CAP flowsheet Hierarchical blocks for unit operations International Conference on Energy Process Engineering June 2011 P 11

12 CAP model validation Thermodynamic modeling Liquid Phase Model- the electrolyte NRTL equation of state Vapor Phase Model- the Redlich-Kwong equation of state Laboratory and Literature -Data was regressed to adjust key parameters such as binary and ternary interaction parameters VLE and thermodynamic parameters established by regressing laboratory data for each of the following contributors: - Pure water - Liquid non-water solvent - Solute in aqueous phase at infinite dilution - Non-idealities Good fit between laboratory data and model predictions for following physical properties: - Viscosity - Density - Surface Tension - Heat Capacity International Conference on Energy Process Engineering June 2011 P 12

13 Data analysis objectives Ensure Steady State Operation by Monitoring: - Flows - Compositions (vapor & liquid) - Temperatures FluTemperatures - Pressures - ph s Reconcile Data for Material Balance Closure: - Identify instrumentation issues Validation of Aspen Plus model predictions against plant data: ue Gas Flow Rate, lbs/h hr roduct, lbs/hr CO2 P /1/11 8:24 AM /1/11 8:24 AM Flue Gas Flow Rate, lbs/hr, XFT0011 +/- 5% 3/1/11 9:36 AM 3/1/11 9:36 AM 3/1/11 10:48 AM 3/1/11 3/1/11 12:00 1:12 PM PM Date and Time Regenerator CO2 Product Flow Rate, lbs/hr 981 Flow AEP Flow average 3/1/11 10:48 AM 3/1/11 12:00 PM 3/1/11 1:12 PM Date and Time 3/1/11 3/1/11 3/1/11 3/1/11 2:24 PM 3:36 PM 4:48 PM 6:00 PM 3/1/11 2:24 PM +/- 5% 3/1/11 3:36 PM 3/1/11 4:48 PM 3/1/11 6:00 PM - Design tool to optimize unit operations Confirming steady-state operating mode International Conference on Energy Process Engineering June 2011 P 13

14 Material balance closure calculations International Conference on Energy Process Engineering June 2011 P 14

15 AEP Mountaineer PVF Data reconciliation results CO 2 material balance from earlier dataset CO 2 material balance closure from recent dataset t Instrumentation resolved to obtain lower deviations International Conference on Energy Process Engineering June 2011 P 15

16 CAP model validation Absorber performance To obtain Absorber performance that matched field data, basic simulation parameters were set as follows: - Equilibrium stages: proportional to packing height - Murphree efficiency as function solution R value, temperature and gas rate - Equilibrium model enables rapid convergence and overall flowsheet modeling efficiency - Validation of rate based model is in progress to enable detailed Absorber modeling Input parameters for the simulation model were obtained from the reconciled material balance worksheet for the following streams: - Flue gas inlet to absorber - Circulating liquid rates through the absorber chillers - Recirculation liquid between regenerator and the absorbers - Recirculation liquid between absorbers - Ammonia make-up International Conference on Energy Process Engineering June 2011 P 16

17 CAP model validation Absorber heat-exchanger duties Predicted d Absorber System, Heat Exchanger Duty Experimental data Excellent agreement between model and experimental data International Conference on Energy Process Engineering June 2011 P 17

18 CAP model validation Regenerator performance To obtain regenerator performance that matched field data, basic simulation parameters were set as follows: Equilibrium i stages in regenerator (proprietary) No Murphree efficiency adjustment applied - Equilibrium Stage Model enables rapid convergence and overall Flowsheet modeling efficiency The input parameters for the simulation model were obtained from the reconciled material balance worksheet for the following streams: Rich solution conditions from Absorber system Rich solution feed temperatures from heat integration system. - CO 2 liberation rate The Output parameters: Reboiler Duty Lean Solution R - Regenerator Bottom Temperature International Conference on Energy Process Engineering June 2011 P 18

19 Mountaineer CAP PVF Regenerator reboiler duty Predic cted Duty MTN-PVF:Regenerator Testing: Regenerator Duty Measured Duty Error Bar -7% Difference between predicted and measured duties is within 7% International Conference on Energy Process Engineering June 2011 P 19

20 Parity plot of lean solution R-value Regenerated Lean Solution R on R Lean Soluti Predicted Measured Lean Solution R Excellent agreement between predicted and measured data International Conference on Energy Process Engineering June 2011 P 20

21 Regenerator sump liquid temperature Predic cted Temp perature Regenerator Bottom Sump liquid Temp Measured Temperature Error Bars +/- 3 deg Good agreement between predicted and measured data International Conference on Energy Process Engineering June 2011 P 21

22 Regenerator temperature profile 11 Regenerator Column: Temperature Profile Predicted Measured Bottom to Top Temperature Excellent agreement for temperature profile International Conference on Energy Process Engineering June 2011 P 22

23 CO 2 product quality ALSTOM :MTN-PVF- CO2 Product Quality CO2 Conc centration in Product Stream (%) Measured Predicted Regenerator Test Campaign -Test Number High purity product International Conference on Energy Process Engineering June 2011 P 23

24 Stripper reboiler duty 9.0 Stripper Reboiler Duty Error Bar + 4% ty Pred dicted Du Measured Duty Error Bar - 8% Good prediction for stripper reboiler duty International Conference on Energy Process Engineering June 2011 P 24

25 Conclusions Process design based on robust simulator validated with measured reconciled data Model show excellent agreement with experimentally measured data for Absorber chiller duties, stripper and regenerator reboiler duties, lean solution R values, regenerator temperature profile Sensitivity and optimization studies using simulation provide significant insight into CAP Technology Support operations - Identify future generation-ii technology improvement FEED studies using validated Aspen model Enables efficient optimization and integration into power plant cycles - Ensures confidence in predicted results for each given application International Conference on Energy Process Engineering June 2011 P 25

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27 AEP MTN CAP PVF validation test campaigns Description Total Tests Planned Number of Test Completed Flue Gas Flow Rate Tests 5 5 DCC/DCH Tests Overall Optimization Test Campaign 1 1 Regenerator Tests 9 9 Rich/Lean Heat Exchanger Network Tests 9 9 Reduced Pressure Regenerator Test 1 1 High Pressure Appendix Stripper Tests 9 6 Low Pressure Appendix Stripper Tests 9 3 Absorber Tests Campaign 13 8 WW-Stripper Tests 12 8 Transient Behavior Tests 5 1 Total Test program designed to validate process adequacy International Conference on Energy Process Engineering June 2011 P 27