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1 4 th Annual Conference on Ammonia, Oct 15 – 16, 2007 Demonstrate Ammonia Combustion in Diesel Engines Aaron Reiter Song-Charng kong Department of Mechanical Engineering Iowa State University Acknowledgements: Iowa Energy Center (Norman Olson, Floyd Barwig)

Demonstrate Ammonia Combustion in Diesel Engines• Baseline engine performance with diesel fuels • Engine test using dual fuel – diesel/NH 3 • Emissions results • Summary

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Text of Demonstrate Ammonia Combustion in Diesel Engines• Baseline engine performance with diesel fuels...

  • 14th Annual Conference on Ammonia, Oct 15 – 16, 2007

    Demonstrate Ammonia Combustion in

    Diesel Engines

    Aaron Reiter

    Song-Charng kong

    Department of Mechanical Engineering

    Iowa State University

    Acknowledgements:Iowa Energy Center (Norman Olson, Floyd Barwig)

  • 2Department of Mechanical Engineering, Iowa State University

    Background

    • Motivation

    • Ammonia (NH3) combustion does not generate CO2

    • Biorenewable; Hydrogen carrier, key to hydrogen economy, etc.

    • Challenges

    • Ammonia is very difficult to ignite

    • Octane number ~ 130

    • Autoignition T ~ 651 ºC (gasoline: 440 ºC; diesel: 225 ºC)

    • Erosive to some materials

    • Fuel induction system modification

    • Less energy content – maximize energy substitution using NH3

    • Others …..

  • 3Department of Mechanical Engineering, Iowa State University

    Approach

    • Introduce ammonia to the intake manifold

    • Create premixed ammonia/air mixture in the cylinder

    • Inject diesel (or biodiesel) to initiate combustion

    • Without modifying the existing injection system

    Diesel ignition

    Induce NH3

    combustion

    Burn out

    premixed NH3

  • 4Department of Mechanical Engineering, Iowa State University

    Presentation Outline

    • Ammonia combustion properties and implications

    • Chemical kinetics study

    • Experimental setup

    • Baseline engine performance with diesel fuels

    • Engine test using dual fuel – diesel/NH3• Emissions results

    • Summary

  • 5Department of Mechanical Engineering, Iowa State University

    Thermodynamics/Chemistry

    • Stoichiometric chemical reaction

    3 2 2 2 20.75 ( 3.76 ) 1.5 1.91NH O N H O N+ ⋅ + ⋅ → ⋅ + ⋅

    2.641418.610313716.0456-33.5NH3Ammonia

    2.766042.3823014.3217---C14.4H24.9Diesel

    2.57814431015.291---C7H17Gasoline

    2.702726.98508.95378.4C2H5OHEthanol

    2.69002012036.43564.7CH3OHMethanol

    Energy Content(MJ/kg-

    stoichiometric mixture)

    Energy Content

    (MJ/kg-fuel)

    Latent Heat

    (kJ/kg)(Air/Fuel)s

    Boiling Point (°C)

    MoleculeFuel

  • 6Department of Mechanical Engineering, Iowa State University

    Thermo-Chemistry

    • Adiabatic flame temperature of NH3/diesel mixture

    • NH3 energy fraction with different equivalence ratios

    0 0.2 0.4 0.6 0.8 11400

    1600

    1800

    2000

    2200

    2400

    fracenergy,NH3

    Tad

    iab

    ati

    c

    [K]

    PHI=0.5

    PHI=1.0

    Phi=0.9

    PHI=0.8

    PHI=0.7

    PHI=0.6

    Adiabatic T is the final equilibrium T.

    In engines, we need to know how fast the reaction goes!

  • 7Department of Mechanical Engineering, Iowa State University

    Chemical Kinetics – Methane/Ammonia

    • Ignition delay – important parameter in CI engines

    • Replacing HC fuel with NH3 will delay ignition

    500

    1000

    1500

    2000

    2500

    3000

    1 10 100 1000

    Autoignition of CH4-NH3-Air System

    Syste

    m T

    em

    pera

    ture

    (K

    )

    Time (ms)

    9.5%-CH4/0%-NH3

    4.5%-CH4/5.0%-NH3

    1.5%-CH4/8.0%-NH3

    autoignition

    Need to rely on HC fuel

    to initiate combustion!

  • 8Department of Mechanical Engineering, Iowa State University

    Chemical Kinetics – Diesel/Ammonia

    • Ignition delay in a constant-volume chamber

    • Diesel/NH3 system

    800

    1000

    1200

    1400

    1600

    1800

    2000

    2200

    2400

    0 0.5 1 1.5 2 2.5

    T History

    10-9020-8040-6090-10

    Syst

    em

    Te

    mp

    era

    ture

    (K

    )

    T ime (ms)

    Diesel-NH3 (%):

    IncreasingNH3

  • 9Department of Mechanical Engineering, Iowa State University

    Test Engine

    • John Deere 4045 Engine

    • Turbocharged, 4-cylinder, 4.5 liter displacement

    • Popular Deere engine – various tracker & Genset applications

    • Peak torque range – 280 ft-lb at 1400 rpm

    • Test conditions

    • Various engine speeds (1000 ~ 1800 rpm)

    • Various engine loads (5% ~ 100%) for each speed

    • Each speed/load point – with and without NH3 induction

    • Test data – torque, BSFC, emissions

    • Only selected data are shown

  • 10Department of Mechanical Engineering, Iowa State University

    Ammonia Fueling System

    • Fuel system

    • Vapor ammonia introduced into the intake duct – after turbo,

    before manifold

    Liquid NH3 tank

    Fuel lineInduction

    point

    Fuel line

  • 11Department of Mechanical Engineering, Iowa State University

    Test Results – Constant NH3 Flow Rate

    • Using one ammonia tank and single fuel line

    0

    100

    200

    300

    400

    500

    -80

    -60

    -40

    -20

    0

    20

    40

    0 20 40 60 80 100 120

    1800rpm Engine Torque

    En

    gin

    e T

    orq

    ue

    (ft

    -lb

    )

    En

    erg

    y b

    y N

    H3

    (%)

    Engine Load (%)

    Diesel baseline

    Diesel+ NH3

    Energy replacement by NH3

    0

    100

    200

    300

    400

    500

    -50

    0

    50

    0 20 40 60 80 100 120

    1400rpm Engine Torque

    Engin

    e T

    orq

    ue (

    ft-lb)

    Energ

    y b

    y N

    H3 (%

    )

    Engine Load (%)

    Diesel baseline

    Diesel+ NH3

    Energy replacement by NH3

  • 12Department of Mechanical Engineering, Iowa State University

    Test Results – Constant Torque

    • Induce more NH3

    • Fixed at different diesel fueling, adjusted NH3 flow

    rate to maintain constant torque

    • Can achieve 5% diesel / 95% NH3 energy ratio

    0

    50

    100

    150

    200

    250

    300

    0 20 40 60 80 100

    1000 rpm

    To

    rqu

    e (

    ft-lb

    )

    Load (%)

    Diesel+NH3

    Diesel

    0

    1

    2

    3

    4

    5

    0 20 40 60 80 100

    1000 rpm

    Flo

    w R

    ate

    (g

    /s)

    Load (%)

    NH3

    Diesel

    0

    200

    400

    600

    800

    1000

    0 20 40 60 80 100

    1000 rpm

    BS

    FC

    (g

    /kW

    -hr)

    Load (%)

    NH3

    DieselBSFC_diesel & BSFC_NH3 calculated separately

    based on individual flow rate and torque contribution

    Poor diesel BSFC

    Poor NH3 BSFC

  • 13Department of Mechanical Engineering, Iowa State University

    Test Results – Variable Torque

    • Goal – to achieve maximum energy substitution

    • Diesel fueling was maintained at approximately 5%

    • Adjusted NH3 rate for desirable engine torque

    0

    50

    100

    150

    200

    250

    0 20 40 60 80 100

    1400 rpm, 5% Diesel Energy

    To

    rqu

    e (

    ft-lb

    )

    Load (%)

    Diesel+NH3

    Diesel0

    1

    2

    3

    4

    5

    6

    0 20 40 60 80 100

    1400 rpm, 5% Diesel Energy

    Flo

    w R

    ate

    (g

    /s)

    Load (%)

    NH3

    Diesel

    0

    200

    400

    600

    800

    1000

    1200

    0 20 40 60 80 100

    1400 rpm, 5% Diesel Energy

    BS

    FC

    (g

    /kW

    -hr)

    Load (%)

    NH3

    Diesel

    Can achieve high NH3 ratio

    but poor fuel economy

  • 14Department of Mechanical Engineering, Iowa State University

    Test Results – Using Biodiesel

    • B100 was used

    • Can achieve similar results as regular diesel fuel

    0

    50

    100

    150

    200

    250

    300

    0 20 40 60 80 100

    1000 rpm, Biodiesel

    To

    rqu

    e (

    ft-lb

    )

    Load (%)

    Diesel+NH3

    Diesel

    0

    50

    100

    150

    200

    250

    300

    10 20 30 40 50 60 70 80

    1400 rpm, 5% Biodiesel Energy

    To

    rqu

    e (

    ft-lb

    )

    Load (%)

    Diesel+NH3

    Diesel

    Constant engine torque Variable engine torque

  • 15Department of Mechanical Engineering, Iowa State University

    Emissions Measurement

    • Gaseous emissions – HC, CO, CO2, NOx, O2

    • Emission analyzer modification for this study

    • Certain materials were replaced by stainless steel

    • Baseline diesel conditions

    2

    4

    6

    8

    10

    12

    0 20 40 60 80 100

    Pure Diesel Fuel

    CO

    2 (

    %)

    Diesel Load (%)

    0

    400

    800

    1200

    1600

    20

    30

    40

    50

    60

    70

    20 40 60 80 100 120

    Pure Diesel Fuel

    NO

    x (

    pp

    m) H

    C (p

    pm

    )

    Diesel Load (%)

    NOx

    HC

    These data will be used for comparisons

  • 16Department of Mechanical Engineering, Iowa State University

    CO2 Results

    • Maintained constant torque by varying diesel & NH3

    2

    4

    6

    8

    10

    12

    0 20 40 60 80 100

    Pure Diesel Fuel

    CO

    2 (

    %)

    Diesel Load (%)

    (repeated plot from previous)

    2

    4

    6

    8

    10

    12

    0

    40

    80

    120

    160

    200

    240

    280

    0 20 40 60 80 100

    Diesel-NH3, 100% Torque

    CO

    2 (

    %)

    To

    tal T

    orq

    ue

    (ft-lb)

    Diesel Load (%)

    CO2

    Torque

    CO2 for 100% diesel

    decreasing CO2 due to increased NH3 fueling

    All the CO2 comes from

    diesel combustion

    CO2 reduction

  • 17Department of Mechanical Engineering, Iowa State University

    NH3 Results

    • Speculation – burning NH3 will …..

    • Increase NOx – due to fuel-bound nitrogen

    • Reduce NOx – due to lower combustion temperature

    • Constant torque conditions

    0

    400

    800

    1200

    1600

    0

    40

    80

    120

    160

    200

    240

    280

    0 20 40 60 80 100

    Diesel-NH3, 100% Torque

    NO

    x (

    ppm

    )

    Tota

    l To

    rque (ft-lb

    )

    Diesel Load (%)

    NOx

    Torque

    NOx for 100% diesel

    Low NOx due

    to low comb T

    High NOx due

    to N in NH3

    ?

  • 18Department of Mechanical Engineering, Iowa State University

    More on NOx Emissions

    • Repeated testing

    Another effect – NH3 can

    reduce NOx in diesel SCR

    (selective catalytic reduction)

    Urea � NH3

    (NH2)2CO + H2O � 2NH3 + CO2

    SCR Catalyst

    4NH3 + 4NO + O2 → 4N2 + 6H2O

    2NH3 + NO + NO2 → 2N2 + 3H2O

    8NH3 + 6NO2 → 7N2 + 12H2O

    0

    200

    400

    600

    800

    1000

    1200

    1400

    1600

    0 20 40 60 80 100

    Diesel-NH3, 100% Torque

    NO

    x (

    ppm

    )

    Diesel Load (%)

    Sudden

    NOx

    decrease

    NOx for 100% diesel

  • 19Department of Mechanical Engineering, Iowa State University

    20

    30

    40

    50

    60

    70

    80

    0

    40

    80

    120

    160

    200

    240

    280

    0 20 40 60 80 100

    Diesel-NH3, 100% Torque

    HC

    (ppm

    )

    Tota

    l Torq

    ue (ft-lb

    )

    Diesel Load (%)

    HC

    Torque

    HC for 100% diesel

    decreasing HC due to lower diesel fueling

    Increasing HC due to lower comb T

    HC Results

    • Maintained constant torque conditions

    Additional reasons for

    HC increase?

    Re-combination between

    C (from diesel) and H

    (from NH3)?

  • 20Department of Mechanical Engineering, Iowa State University

    Biodiesel/NH3 Emissions

    • Same trend as in the diesel case

    • B100 produced lower HC than regular diesel at baseline

    0

    400

    800

    1200

    1600

    0

    50

    100

    150

    200

    250

    300

    0 20 40 60 80 100

    B100-NH3, 100% Torque

    NO

    x (

    ppm

    )

    Tota

    l Torq

    ue (ft-lb

    )

    B100 Load (%)

    NOx

    Torque

    NOx for 100% B100

    Low NOx due to lower comb T of NH3

    Increasing NOx due to nitrogen molecule in NH3

    20

    30

    40

    50

    60

    70

    80

    0

    50

    100

    150

    200

    250

    300

    0 20 40 60 80 100

    B100-NH3, 100% Torque

    HC

    (p

    pm

    )

    To

    tal T

    orq

    ue

    (ft-lb)

    B100 Load (%)

    HC

    Torque

    HC for 100% B100

    decreasing HC due to lower diesel fueling

    Increasing HC due to lower comb T

  • 21Department of Mechanical Engineering, Iowa State University

    Summary

    • Demonstrated ammonia combustion in diesel engines

    • Premixed NH3/air with direct-injection diesel for ignition

    • Effective in CO2 reduction while maintaining the same engine

    torque output

    • Reasonable fuel economy between 20~60% diesel fueling

    • NOx emissions are not a concern as originally expected

    • Lower NOx for certain diesel fueling range

    • HC has an opposite trend to NOx

    • Further investigations are required for –

    • Emissions formation mechanisms

    • Precise control of NH3/diesel flow rates for optimal fuel economy

    and exhaust emissions