Is Oxyfuel Combustion an Option for Gas Turbines?

Peter Kutne, Bhavin K. Kapadia, Wolfgang Meier DLR Institute for Combustion Technology

CCT 2009 Dresden > Peter Kutne > 19.05.2009

Slide 2

Overview of Presentation

Institute of Combustion Technology

Motivation

BIGCO2 project

Experimental setup

Results

Summary & Outlook

CCT 2009 Dresden > Peter Kutne > 19.05.2009

Slide 3

Combustion for Gasturbines

Objectives:

• Reduction of pollutants NOx , soot particles, UHC, CO2

• Reliability of unsteady combustion processes ignition, extinction, thermoacoustic

• Fuel flexibility kerosene, natural gas quality, alternatives as syngas and synfuels

• Burner systems and power plant concepts

CCT 2009 Dresden > Peter Kutne > 19.05.2009

Slide 4

Institut of Combustion Technology interdisciplinary competences

Combustion SystemsNumerical Simulation

Temperature

CO mole fraction

DiagnosticsTestrigsKineticsReaction A n Eact/R Reference

CH3 + H (+M) = CH4 (+M) 1.69E+14 0.0 0 Leeds mechanism Low pressure limit : 1.41E+24 -1.8 0 Troe centering 3.70 3315 61 N2/0.4/ O2/0.4/ CO2/1.5/ H2O/6.5/ C2H6/3/ CO/7.5/ CH4/3/ AR /0.35/2CH3 (+M) = C2H6(+M) 3.61E+13 0.0 0 Leeds mechanism Low pressure limit : 3.63E+41 -7.0 1390 Troe centering 0.62 73 1180 N2/0.4/ O2/0.4/ CO2/1.5/ H2O/6.5/ C2H6/3/ CO/7.5/ CH4/3/ AR /0.35/2 CH3 = C2H5 + H 2.80E+13 0 6800 Frank, Braun-UnkhoffC2H5 + M = C2H4 + H + M 2.0E+15 0 15600 Frank, Braun-UnkhoffC2H4 + M = C2H3+ H 7.40E+17 0.0 48603.6 Leeds mechanism N2/0.4/ O2/0.4/ CO2/1.5/ H2O/6.5/ C2H6/3/ CO/7.5/ CH4/3/ AR /0.35/C2H2+ H (+M) = C2H3(+M) 8.43E+12 0.0 1300.2 Leeds mechanism Low pressure limit : 3.43E+18 0 739.7 Troe centering 1.0 1.0 1.0 1231 N2/0.4/ O2/0.4/ CO2/1.5/ H2O/6.5/ C2H6/3/ CO/7.5/ CH4/3/ AR /0.35/C2H2 + O = CH2 + CO 1.63E+14 0 4975 Bhaskaran, FrankC2H2 + O = HCCO +O 3.98E+14 0 5365 Bhaskaran, FrankH + O2 = OH + O 2.47E+14 0 8696 Frank, JustCH3 + O2 = CH3O +O 2.10E+12 0 12242 BraUn, Frank, NaumannCH3 + O2 = CH2O +OH 3.10E+10 0 4402 BraUn, Frank, NaumannCH3O = CH2O + H 1.50E+14 0 14600 CEC Data EvaluationCH3 + NO = H2CN + OH 9.70 E+11 0 11040 BraUn, Frank, NaumannCH3 + NO = HCN + H2O 8.32E+11 0 8100 Wintergerst, FrankCH3 + O2 (+M) = CH3O2 (+M) 7.80 E+08 1.2 0 Bromly et al.(1996) Low pressure limit : 5.80 E+25 -3.3 0CH3O2 + NO = CH3O + NO2 3.10 E+12 0 -358 Schelb, BraUn, FrankCH3O2 + CH3 = CH3O + CH3O 3.24 E+13 0 0 Schelb, BraUn, FrankCH3O + NO2 = CH2O + HONO 9.37 E+12 0 2285 Bromly et al.(1996)CH3O + NO = CH2O + HNO 1.95 E+12 0 -390 Schelb, BraUn, Frank

( k = A Tn exp(-Ea/RT) units: mol / cal / cm / s / K )

COMPREHENSIVE

REDUCEDMECHANISM

VALIDATION

APPLICATION

REACTION MECHANISM

CCT 2009 Dresden > Peter Kutne > 19.05.2009

Slide 5

Motivation

Oxyfuel combustion for gas turbines connects the efficient combined cycle process with the post combustion capture option of the Oxyfuel process

It is suited for all kind of fossil fuels, e.g. natural gas or syngas from coal

On paper, it is a highly efficient way to avoid CO2 emissions while using fossil fuels

Oxyfuel combustion for gas turbines has never been taken beyond thermodynamic calculations

CCT 2009 Dresden > Peter Kutne > 19.05.2009

Slide 6

Differences between Oxyfuel combustion and air combustion for gas turbines

Steam and CO2 as a working fluid of the turbo machineryRedesign of the compressor and turbine parts necessary

Physical propertiesheat capacityCO2 is an infrared active moleculeGas transport properties (diffusivity)

Chemical properties high chaperon efficiency (enhances third body reactions)Participation in chemical reactions like

HCOOHCO +⇔+ 2

CCT 2009 Dresden > Peter Kutne > 19.05.2009

Slide 7

BIGCO2 phase II - CO2 Management Technologies for Future Power Generation

Enabling sustainable gas-fuelled power generation based on carbon capture and storage

High temperature oxygen and hydrogen membranesPost combustion CO2 captureOxyfuel combustion & chemical looping CO2 storage

Duration: 2007 - 2011Volume: 16 Mio€Partners: StatoilHydro, GE Global Research, Statkraft, Aker Kvaerner, Shell, TOTAL, ConocoPhillips, Alstom, Research Council of Norway (178004/I30), Gassnova (176059/I30), SINTEF, NTNU, University of Oslo, CICERO

CCT 2009 Dresden > Peter Kutne > 19.05.2009

Slide 8

BIGCO2 phase II - CO2 Management Technologies for Future Power Generation – DLR part

Fundamental research on Oxyfuel combustion for gas turbines

Development and validation of kinetic reaction modelsLaminar flame speed measurementsIgnition delay time measurements

Experiments on swirl stabilized Oxyfuel flamesStability analysis at atmospheric pressureDetailed measurements at atmospheric pressureSetup of a high pressure test rig for Oxyfuel combustionDetailed measurements under gas turbine conditions

CCT 2009 Dresden > Peter Kutne > 19.05.2009

Slide 9

Experimental setup

Burner:Gas turbine model combustorTwo co-swirled oxidizer flowsFuel injection through a ring between the oxidizer inlets

Operation conditions:Fuel: CH4Thermal power: 10 - 30 kWO2 fraction: 20 % - 40 %fuel / oxidizer ratio: φ

= 0.5 – 1

Flame monitoring:OH*- chemiluminescence

CCT 2009 Dresden > Peter Kutne > 19.05.2009

Slide 10

Flame stabilization for different operating conditions

CCT 2009 Dresden > Peter Kutne > 19.05.2009

Slide 11

Variations in oxygen concentration

Oxygen level of the oxidizer has a large effect on flame speedAt 40% O2 the laminar flame speed is comparable to a CH4 /air flameTo meet specifications for RIT (1600 K) the O2 level has to be around 20%, which could not be stabilized in the atmospheric experiments without preheating

(a) 26 % O2 (b) 30 % O2 (c) 34 % O2 (d) 38 % O2

CCT 2009 Dresden > Peter Kutne > 19.05.2009

Slide 12

Variations in stoichiometry

(a) φ

= 0.54 (b) φ

= 0.61 (c) φ

= 0.82 (d) φ

= 1.0016.6 kW 18.7 kW 24.9 kW 29.9 kW

Stoichiometry variation has only a small effect on flame shapeIncrease in OH*-chemiluminescence intensity due to higher heat release rateInlet velocity of the fuel changes from 26 m/s to 46 m/s (a-d)

CCT 2009 Dresden > Peter Kutne > 19.05.2009

Slide 13

Summary & outlook

Combustion behavior of different Oxyfuel/CH4 flames in a swirl stabilized burner was characterized over a wide parameter range at atmospheric conditionsFlame characteristics are quite different from CH4 /air flames at comparable conditionsOxygen level has a large influence on the combustion behavior

Because of the different physicochemical properties it is not possible to predict the combustion behavior at elevated pressure from the atmospheric resultsThe pressure dependence has to be analyzed to determine if Oxyfuel combustion in a gas turbine is a viable way

CCT 2009 Dresden > Peter Kutne > 19.05.2009

Slide 14

Acknowledgements

The presented work forms a part of the BIGCO2 project, performed under the strategic Norwegian research program Climit. The authors acknowledge the partners:

StatoilHydro, GE Global Research, Statkraft, Aker Kvaerner, Shell, TOTAL, ConocoPhillips, Alstom, the Research Council of Norway (178004/I30), Gassnova (176059/I30) for their support.

Is Oxyfuel Combustion an Option for Gas Turbines?��Peter Kutne, Bhavin K. Kapadia, Wolfgang Meier�DLR Institute for Combustion Technology�Overview of PresentationCombustion for Gasturbines Institut of Combustion Technology�interdisciplinary competencesMotivationDifferences between Oxyfuel combustion and air combustion for gas turbinesBIGCO2 phase II - CO2 Management Technologies for Future Power GenerationBIGCO2 phase II - CO2 Management Technologies for Future Power Generation – DLR partExperimental setupFlame stabilization for different operating conditionsVariations in oxygen concentrationVariations in stoichiometrySummary & outlookAcknowledgements