A Computational Workbench Environment for Virtual Power Plant

Process/Equipment Co-Simulation for Gasification and Combustion-based Energy Applications Mike Bockelie Martin Denison, Dave Swensen Reaction Engineering International NETL 2009 Workshop on Advanced Process Engineering Co-Simulation (APECS) October 20-21, 2009, Pittsburgh, PA USA Acknowledgement “This material is based upon work supported by the Department of Energy under award number DE-FC26-00FNT41047 and DE-FC26-05NT42444” Vision 21 Program “Computational Workbench Environment for Virtual Power Plant Simulation” DOE NETL (COR=John Wimer, Bill Rogers, DE-FC26-00FNT41047) Clean Coal R+D Project “A Virtual Engineering Framework for Simulating Advanced Power Systems” DOE NETL (COR=Ron Breault, DE-FC26-05NT42444 ) "This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.“ 2 Co-Simulation and Power Systems • Coal combustion  CO2 + Q (heat) – Use heat to generate electricity in steam turbine – Conventional, SuperCritical , UltraSuperCritical • Relatively Simple plant layout – Oxy-fire boiler • Recycle of CO2 complicates plant and operation – Flue gas conditioning • Reagents, sorbents for pollution control – Water consumption, heat integration • Natural Gas combustion  CO2 + Q (heat) • – Use natural gas to generate electricity in combustion turbine – Combined cycle (NGCC) system – Performance monitoring, Flue gas conditioning Coal Gasification  Syngas (CO, H2, CO2, H2O, CH4) – Use syngas to generate electricity in combustion turbine – Combined cycle (IGCC) system • More complicated plant layout ~ “chemical plant” • Many “recycle” loops and coupling for gas, liquid, solids streams Conventional Power Plant 4 5 Advanced Power Systems [J. Phillips, “IGCC 101”, GTC 2009] http://www.gasification.org/library/overview.aspx Advanced Power Systems – FutureGen [D. Brown, “Rebirth of FutureGen at Mattoon,” GTC 2009] http://www.gasification.org/library/overview.aspx Advanced Power Systems - power, multi-product - CO2 capture ready - operating plant ~ 2020 [L. Ruth, DOE-NETL, US-UK Collaboration Workshop, June, 2003] DOE Techline - http://www.netl.doe.gov/publications/press/2000/tl_vis21sel2.html 8 Why Use Modeling? Cost effective approach for evaluating performance, operational impacts & emissions  Improve understanding  Estimate performance  Assist with conceptual design  Identify operational problems  Cheaper than testing  More detailed information than testing  Does NOT make decisions for engineers, but does help them be more informed 9 Simulation Capabilities • Model development and use are correlated with: – Process knowledge – Modeling techniques – Computational resources – Value to market Spreadsheet correlations Process models Zonal models CFD models System models / Workbenches Increasing Process Knowledge and Computer Resources • Many types of simulation tools – each serves a different purpose Specialized Software Systems • • • • • REKS-Modlink (chemical kinetics) MerSim (plant mercury simulation) Expert Series: FurnaceExpert & SteamGenExpert (flowsheet model) Configured fireside simulators FireExplorer® 10 AspenPlus IGCC Flowsheet* 11 * Ciferno, J. and Klara, J., “2006 Cost & Performance Comparison of Fossil Energy Power Plants,” Pittsburgh Coal Conf., 2006b * Ciferno, J., “2006 Cost & Performance Comparison of Fossil Energy Power Plants,” Clearwater Conf. 2006a Equipment Models* • Gasifiers • Heat Exchangers • • Air Separation Unit (ASU) Gas Clean Up (cold, warm, hot) • Gas Turbine Equipment • • • expanders, combustors Solid Oxide Fuel Cells (SOFC) Reactors with Kinetics • SOFC Exhaust Gas Combustors • Membrane Based Gas Separation Units • Balance of Plant APECS Framework – entrained flow (slurry, dry, 1 stage, 2 stage) – transport reactor – syngas cooler, HRSG, recuperator – cyclone, chlorine guard, bulk desulfurizer, – sulfur polisher, SCR, – AGR, Carbon Bed – turbine, compressors, CAPE-Open – Perfectly Stirred Reactor (PSR), Plug Flow Reactors (PFR) REI Models – dump, catalytic Project Team Models – water gas shift membrane reactor * Bockelie, M., Swensen, D.A., Denison, M.K., Maguire, M., Yang, C., Chen, Z., GE GateCycle Sadler, B., Senior, C.L., Sarofim, A.F. “A Computational Workbench Environment for Virtual Power Plant Simulation”, Contract DE-FC26-00NT41047, Final Report, December, 2004. 12 Cryogenic ASU Model • PRAXAIR provided ASU model as a HYSYS network • REI replicated HYSYS model with AspenPlus network – Benchmarked AspenPlus and HYSYS versions of model • good agreement obtained • must use comparable Eqn. of State for properties (Peng-Robinson) AspenPlus network consists of • 3 Distillation Column (RadFrac) blocks • 3 Heat exchanger (MHeatX) blocks • 3 Heater (Heater) blocks • 5 Splitter (FSplit) blocks • 2 Compressors (Compr) blocks • 2 Pump blocks • 3 Valve blocks 13 14 Models – GE GateCycle • Create CAPE-Open Coupling to GE GateCycle • • ~60 model inputs • ~65 model outputs APECS - COM CAPE-Open COM-CORBA Bridge CORBA CAPE-Open Wrapper GE GateCycle Automation Interface REI + Enginomix 7FB Gas Turbine Model note: user must have a valid GE GateCycle license to exercise this capability [AIChE 2006] Software Layers – Access selected equipment models from APECS – 7FB Gas Turbine is first model chosen – Prototype of APECS 7FB model is being tested Aspen Plus 15 Entrained Flow Gasifier Model • Model Development – CFD + Process models • Allows modification of 1 stage Axial Gas Velocity, m/s – Process conditions, burner characteristics – Fuel type, slurry composition – gross geometry • Generic Configurations: 2 stage – downflow / upflow – 1 stage / 2 stage – based on public information • Define Parameters with DOE – Improved physical models • pressure effects on radiation heat transfer • reaction kinetics – high pressure, gasification w / inhibition • slag, ash (vaporization), tar, soot Particle Char Fraction • Collaboration – N. Holt (EPRI) – T.Wall,.. (Black Coal CCSD, Australia) – K.Hein (IVD, U. of Stuttgart) [Clearwater 2006], [PCC 2006], [Clearwater, 2008] H2 Glacier Software • Glacier is REI’s in-house, CFD-based combustion simulation software • Over 30 years of development • Over 15 years of industrial application • Designed to handle “real-world” applications – Judicious choice of sub-models & numerics – Qualified modelers Modeling Coal Combustion • Computer model represents – Furnace geometry Turbulence Combustion Chemistry Radiation & Convection – Operating conditions – Combustion processes – Pollutant formation • Accuracy depends on – Input accuracy – Numerics – Representation of physics & chemistry Finite-rate Chemistry Coal-fired Combustion Surface Properties Particle Reactions Particle Deposition Flowing Slag Model • • Model accounts for: – – – – Wall refractory properties Back side cooling Fire side flow field + heat transfer Particle deposition on wall • • • • Local Deposition Rate Fuel ash properties Composition (ash, carbon) Burning on wall Slag model computes – Slag viscosity • Tcv = critical viscosity • ash composition – Slag surface temperature – Liquid & frozen slag layer thickness – Heat transfer through wall Based on work by [Benyon], [CCSD], [Senior], [Seggiani] For model details see - Pittsburgh Coal Conference 2002 [Dogan et al, GTC2002] Gasifier Slag Viscosity Model 1700 1600 1500 T (K) 1400 1300 1200 1100 1000 900 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 Oxidizer Flow (kg/s) Derived for a range of coal ashes Curve fit as a function of SiO2, TiO2, Al2O3, Fe2O3, CaO, FeO, MgO, Na2O, K2O and temperature. References: Kalmanovitch , D.P. And Frank, M., “An Effective Model of Viscosity of Ash Deposition Phenomena,” in Proceedings of the Engineering Foundation Conference on Mineral Matter and Ash Deposition from Coal, ed., Bryers, R.W. And Vorres, K.S.,Feb. 22-26, 1988. Urbain, G., Cambier, F., Deletter, M., and Anseau, M.R., Trans. J. Gr. Ceram. Soc., Vol. 80, p. 139, 1981. 19 Viscosity Model 100 1700 1600 1500 T (K) 1400 1300 1200 1100 1000 900 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 Oxidizer Flow (kg/s) Slag A measured Viscosity (Pa s) Slag A model Slag B measured 10 Slag B model Slag F measured Slag F model Slag G measured Slag G model 1 Slag K measured Slag K model 0.1 1550 1600 1650 1700 1750 1800 1850 Temperature (K) Gasifier slag data from Mills, K.C., and Rhine, J.M., “The measurement and estimation of the physical properties of slags formed during coal gasification 1. Properties relevant to fluid flow.,” Fuel vol. 68, pp. 193-198, 1989. 20 CO Flowing Slag Model Gasifier height, m Slag Surface Temperature Liquid Slag Thickness Solid Slag Thickness 8 8 8 7 7 7 6 6 6 5 5 5 4 4 4 3 3 3 2 2 1 1 Gas temperature, K 2 1 0 1400 1700 2000 2300 Slag surface temperature, K 2600 0 0 0 0.005 0.01 0.015 Liquid slag thickness, m Test case: - 1 stage, upflow Prenflo Gasifier at Puertollano, Spain IGCC plant - 2600 tpd, dry feed, opposed fired - water jacket to cool refractory 0.02 0 0.02 0.04 0.06 Solid slag thickness, m Seggiani Benyon REI 0.08 Carbon Conversion 22 Gas Temp., K • Carbon Conversion vs Time in PFR • Contributions of Volatile Release and Gasification Rxns [Bockelie et al, 2002]  [Roberts, Tinney, & Harris, CCSD, 2005]  symbols refer to different coals Particle Coal Fraction Axial Gas Velocity, m/s Particle Char Fraction Effect of CO Inhibition on Carbon Gasification Rate • [Roberts, Tinney, & Harris, CCSD, 2005] • symbols refer to different coals increase CO conc. decrease relative gasification rate 23 CO reduces gasification rate Gasification Kinetics – with inhibition • CO, CO2, H2, H2O rs (1 / s ) k1 PCO2 1 k 3 PCO2 k 4 PCO k 2 PH 2O k 5 PH 2O k 6 PH 2 Slurry Dry 1 k i 0 exp Ei RT 0.001 rs/rs(PCO=0) ki PCO2, atm 0.010 0.020 0.040 0.080 0.1 0.100 0.150 0.200 1600K, 60 atm 0.01 1.0E-03 1.0E-01 1.0E+01 PCO/PCO2 24 [van Heek & Muhlen, 1991] 6 0.5 5 0.4 CO 4 3 Slurry feed SR=0.52 70 atm. H2O gasification 0.3 0.2 2 CO2 gasification 1 0.1 0 CO mole fraction Gasification Rate, g/g/s Gasification Kinetics – CO effects 0 0 1 2 3 8 0.7 7 0.6 Dry feed SR = 0.48 70 atm. 4 0.5 0.4 0.3 3 2 H2O gasification 0.2 CO2 gasification 1 0.1 0 0 0 25 2 4 Time, s 6 8 Gasification rate for H2O is greater than for CO2 CO mole fraction Gasification Rate, g/g/s Time, s 6 5 Presence of CO reduces gasification rate Effect of Temp. on Carbon Conversion • • Increase gasifier volume (residence time)  small benefit Increase temperature  increase carbon conversion BUT can reduce refractory life Carbon Conversion vs. Residence Time Carbon Conversion, % 100 95 70 atm. 90 1531 K, SR = 0.45 (2300F) 1707 K, SR = 0.52 (2610F) 1797 K, SR = 0.57 (2775F) 85 80 Increase Stoichiometric Ratio 75 70 0 1 2 Residence time, s 26 3 4 = dry feed, SR = 0.48 2079K (3200F) Tar & Soot Model • Semiempirical model* – Coal-derived soot is assumed to form from only tar. – Tar yields is calculated by CPD model† based on measured coal characteristics. – Three equations for conservation of the mass of soot and tar, and the number of soot particles. * Brown, A.L.; Fletcher, T.H. Energy Fuels 1998, 12, 745-757. † Fletcher, T.H.; Kerstein, A. R.; Pugmire, R. J.; Solum, M. S.; Grant, D. M. Energy Fuels 1992, 6, 414-431. Assumed Soot Formation Mechanism Brown, A.L.; Fletcher, T.H. Energy Fuels 1998, 12, 745-757. Char Light Gas Motivation: 1. Coal-derived soot undergoes different mechanism than gaseous fuel (limited acetylene involvement) 2. The sum of soot and tar is relatively constant during pyrolysis. Agglomeration Formation Primary Soot Devolatilization Coal Tar Soot Agglomerates Light Gas Gasification CPD Soot Model 28 Soot Model Evaluation 5.0E-007 240 4.5E-007 4.0E-007 210 3.5E-007 200 3.0E-007 190 2.5E-007 180 170 2.0E-007 160 1.5E-007 150 1.0E-007 140 5.0E-008 130 0.8 0.9 1.0 Burner Stoichiometric Ratio 1.1 0.0E+000 Soot Volume Fraction 220 Measurements GLACIER 4.5E-007 Soot Volume Fraction NOx, ppm 230 4.0E-007 3.5E-007 3.0E-007 2.5E-007 2.0E-007 1.5E-007 1.0E-007 5.0E-008 0.0E+000 100 150 200 250 Exit NOx, ppm 29 30 Mineral Matter Transformation Pathways [Lee, 2000] 1) 2) 3) Fly ash (residual solid) Organometallics (solid + vapor) Vapor (fume) created by reduction of stable condensed metal oxide (SiO2, MgO, CaO, Al2O3, FeO) to more volatile suboxides (SiO, Al2O) or metals (Mg, Ca, Fe) MOn (c) CO MOn 1 (v) CO2 31 2 Stage Gasifier – Vaporization Along Representative Particle Trajectories 25 to 60 micron 6-4-08 Gasifier – Flow Sheet / Process Model • fast running model to asses operating conditions – 1 & 2 Stage designs • mass & energy balance • • slag flow indicator Includes impacts of: – particle burnout + equilibrium chemistry – heat transfer – Fuel type, Unburned carbon, recycled char, incomplete burnout – Oxidant conditions – Wet vs Dry feed – Fuel particle size Zonal Equilibrium Model Particle Burnout Model Oxidant Fuel Temperature Unburned Carbon Unburned Carbon Temperature Cold Gas Efficiency Fuel Composition Transport Fluid Refractory Residence Time: Qloss Slag AspenPlus IGCC Flowsheet* 33 * Ciferno, J. and Klara, J., “2006 Cost & Performance Comparison of Fossil Energy Power Plants,” Pittsburgh Coal Conf., 2006b * Ciferno, J., “2006 Cost & Performance Comparison of Fossil Energy Power Plants,” Clearwater Conf. 2006a AspenPlus IGCC Flowsheet* • 34 Using NETL AspenPlus IGCC flowsheets [Ciferno et al., 2006]* (NP) – Cost and Performance evaluations with AspenPlus flowsheets for plant configurations with different gasifiers with and w/o CO2 capture – Extensive AspenPlus process simulations • Flowsheets use ~200 blocks and 500 streams • NP = non-proprietary information version of flowsheets * Ciferno, J. and Klara, J., “2006 Cost & Performance Comparison of Fossil Energy Power Plants,” Pittsburgh Coal Conf., 2006b * Ciferno, J., “2006 Cost & Performance Comparison of Fossil Energy Power Plants,” Clearwater Conf. 2006a NETL IGCC Flowsheet with ASU • Import as hierarchal library to replace single unit op ASU • Must alter flowsheet convergence parameters / sequence 35 Simple vs. Detailed ASU Case 1 Case 2 • Detailed ASU – not as robust as simple model – provides much more information about localized processes important for ASU operation • But only minor differences in predicted overall plant performance 36 37 NETL IGCC Flowsheet with Gasifier Process Model Gasifier Oututs Gasifier in IGCC flowsheet. Gasifier Inputs A Framework for Virtual Simulation of Advanced Power Systems A CMU, ISU, REI coordinated effort Key Features • Virtual engineering based • Hierarchy of Models • View and Interrogate at Multiple Levels • Platform Independent • Open Source, Extensible, Flexible • Supports CO2 capture and FutureGen Acknowledgements Neville Holt (EPRI) Gasifier System Configurations & Validation Terry Wall, David Harris, Daniel Roberts et al (CCSD, Australia) Coal Gasification Data and Mineral Matter Sub-models Klaus Hein, Bene Risio (U. Stuttgart/IVD, RECOM) Coal gasification in the EU Chris Johnson UU Scientific Computing and Imaging Group (Visual Influence) SCIRun Support/Enhancement, PSE Design Mark Bryden, Doug McCorkle et al (Iowa State U. - Virtual Reality Application Center) Virtual Engineering for Power Plant Simulation Ed Rubin, Mike Berkenpas et al (Carnegie Mellon U.) IECM Steve Zitney, Jared Ciferno, Mike Matuszewski (DOE-NETL) – Aspen Process Modeling AspenTech Jens Madsen, Sorin Munteau (ANSYS-Fluent) Praxair American Electric Power, Ameren 39