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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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  • 1 4th 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)

  • 2 Department 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 …..

  • 3 Department 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

  • 4 Department 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

  • 5 Department 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

  • 6 Department 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 1 1400

    1600

    1800

    2000

    2200

    2400

    fracenergy,NH3

    T a d

    ia b

    a ti

    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!

  • 7 Department 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

    S y s te

    m T

    e m

    p e ra

    tu re

    ( 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!

  • 8 Department 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

    10-90 20-80 40-60 90-10

    S y st

    e m

    T e

    m p

    e ra

    tu re

    ( K

    )

    T ime (ms)

    Diesel-NH3 (%):

    Increasing NH3

  • 9 Department 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

  • 10 Department 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 line Induction

    point

    Fuel line

  • 11 Department 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

    E n

    g in

    e T

    o rq

    u e

    ( ft

    -l b

    )

    E n

    e rg

    y b

    y N

    H 3

    (% )

    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

    E n g in

    e T

    o rq

    u e (

    ft -l b )

    E n e rg

    y b

    y N

    H 3 (%

    )

    Engine Load (%)

    Diesel baseline

    Diesel+ NH3

    Energy replacement by NH3

  • 12 Department 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

    T o

    rq u

    e (

    ft -l b

    )

    Load (%)

    Diesel+NH3

    Diesel

    0

    1

    2

    3

    4

    5

    0 20 40 60 80 100

    1000 rpm

    F lo

    w R

    a te

    ( g

    /s )

    Load (%)

    NH3

    Diesel

    0

    200

    400

    600

    800

    1000

    0 20 40 60 80 100

    1000 rpm

    B S

    F C

    ( g

    /k W

    -h r)

    Load (%)

    NH3

    DieselBSFC_diesel & BSFC_NH3 calculated separately

    based on individual flow rate and torque contribution

    Poor diesel BSFC

    Poor NH3 BSFC

  • 13 Department 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

    T o

    rq u

    e (

    ft -lb

    )

    Load (%)

    Diesel+NH3

    Diesel 0

    1

    2

    3

    4

    5

    6

    0 20 40 60 80 100

    1400 rpm, 5% Diesel Energy

    F lo

    w R

    a te

    ( g

    /s )

    Load (%)

    NH3

    Diesel

    0

    200

    400

    600

    800

    1000

    1200

    0 20 40 60 80 100

    1400 rpm, 5% Diesel Energy

    B S

    F C

    ( g

    /k W

    -h r)

    Load (%)

    NH3

    Diesel

    Can achieve high NH3 ratio

    but poor fuel economy

  • 14 Department 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

    T o

    rq u

    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

    T o

    rq u

    e (

    ft -lb

    )

    Load (%)

    Diesel+NH3

    Diesel

    Constant engine torque Variable engine torque

  • 15 Department 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

    C O

    2 (

    % )

    Diesel Load (%)

    0

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