Methane Powered Heavy Duty Engine with Low Fuel Consumption and Euro VI Emission Compliance

X. Auvray1, N. Sadokhina1, G. Smedler2, U. Nylén3, M. Holmström4, Louise Olsson1

1Chalmers University of Technology, Chemical Engineering; Competence Center for Catalysis, 412 96, Göteborg, Sweden

2Johnson Matthey AB, 421 31, Västra Frölunda, Sweden3Scania CV AB, 151 87 Södertälje, Sweden

4AVL MTC Motortestcenter AB, Box 223, 13623, Haninge, Sweden

The target for this project proposal is to address the problem of combining low energy-specific fuel consumption with low GHG and very low toxic emissions for a state-of-the-art CNG/CBG engine.

The project will support the introduction of renewable fuels for Euro VI vehicles. Euro VI emissions will be met by engine tuning and by developing next generation of exhaust

aftertreatment system for methane powered engines. Reduction of CO2 emissions will be reduced by 10 %. Catalyst model for methane exhaust system for both stoichiometric and mixed lean

combustion

Project time: 2013-03-01 - 2015-08-30 Program: Energy and Environment Funded: 50% from The Swedish Energy Agency

Methane Powered Heavy Duty Engine with Low Fuel Consumption and Euro VI Emission Compliance

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Compressed Natural Gas as vehicle fuel

• To decrease mineral oil consumption

• To decrease greenhouse gas and pollutants emissions

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Compressed Natural Gas as vehicle fuel: emissions

• Natural gas is mainly composed of methane• Natural gas impurity content (ex: S) is low• CNG vehicles emit less:

– CO2

– NOx

– Particulate matters (PM)– Volatile Organic Compounds (VOC)

• CNG vehicles emit methane (GHP= 23)

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DateRefuelling StationsNatural Gas VehiclesCountry

Natural gas vehicles: worldwide count

www.iangv.org

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Support: 20 wt.% Ce-Al2O3 (S = 114 m2/g) calcined in air at 900 oC, 2 h;

Catalyst preparation:

The catalyst contains 3.2 wt.% of Pd and 0.6 wt.% Pt on 20 wt.% Ce-Al2O3

Pretreatment:

1. Reduction T = 500 oC; 2% H2; Ar; 30 min

2. Lean/rich/lean cycle T = 700 °C

Lean: 0,03% CO; 0,05% NO; 0,05% CH4; 8% O2; 5% H2O; Ar; 60 min

Rich: 2% H2; 5% H2O; Ar; 20 min

3. Ageing T = 700 C; 8% O2; 5% H2O; Ar; 30 min

Ramp test (Lean conditions):

Heating/cooling cycleT = 150 - 700 oC; ramp = 5 °/min

Catalytic activity measurement:

Ceramic monolith: 400 cpsi; l = 20 mm, d = 21 mm;Washcoat: 500 mg calcined in air, 600 oC, 2 h

Pre-treatment

0 60 120 180 240 300 360 420 480 540 6000

100

200

300

400

500

600

700

Tem

pera

ture

(o C

)

Time (min)

Ramp test

1

2; 3

Methane oxidation: simple gas composition

Conditions:0.05% CH4; 8% O2; Ar T = 150 - 700 oC; ramp = 5 °/min

200 250 300 350 400 450 500 550 6000

25

50

75

100

3.2Pd-0.6Pt/Ce-Al2O3

without H2O

solid line - heatingdash line - cooling

CH

4 con

vers

ion

(%)

Temperature (oC)

Temperature of 50% conversion CH4, oC

Gas mixture Heating Cooling

CH4 + O2 329 305 24 oC

Mixture: CH4 + O2

heating cooling

Eact = 101 kJ/mol Eact = 77 kJ/mol

Methane oxidation: complex gas composition

Conditions:0.05% CH4; 8% O2; 0.03% CO; 0.05% NO; Ar T = 150 - 700 oC; ramp = 5 °/min

200 250 300 350 400 450 500 550 6000

25

50

75

100

3.2Pd-0.6Pt/Ce-Al2O3

without H2O

solid line - heatingdash line - cooling

CH

4 con

vers

ion

(%)

Temperature (oC)

Temperature of 50% conversion CH4, oC

Gas mixture Heating Cooling Amplitude

CH4 + O2 329 305 24 oC

CH4 + O2 + CO + NO 348 332 16 oC

Mixture: CH4 + O2 + CO + NO

heating cooling

Eact = 115 kJ/mol Eact = 83 kJ/mol

Inhibiting effect of CO + NO:

-Increase of Eact

-Increase of T50

-Decrease of hysteresis amplitude

Reaction order calculation: complex gas composition

Conditions: without H2O; 0.05% CH4; 0.05% NO; 0.03% CO; 8% O2; Ar T = 305 oC

Reaction order

CO conc. CH4 conc. O2 conc. NO conc.

100; 300; 500; 700; 800 ppm;Order is 0

200; 500; 800; 1100; 1400 ppm; Order is 0.4

0.14; 2; 5; 8;12 %; Order is 0.1

100; 300; 500; 700; 1100 ppm;Order is – 0.3

CH4 change O2 change NO changeCO change

0 CO 0 CH4 0 O2

0 NO

O2 treatment700 - 305 oC

O2 treatment700 - 305 oC

O2 treatment700 - 305 oC

100 ppm800 ppm

200 ppm

1400 ppm0.14 % 12 %

100 ppm

1100 ppm

60

50

40

30

20

10

0

CH4 c

onve

rsio

n (%

)

0 120 240 360 480 600 720 840Time (min)

960 1080

Kinetic modeling

Reaction: CH4 + 2O2 CO2 + 2H2O

Reaction rate: r= k [CH4]α [O2]β

Rate constant: k=A exp(-Eact/(RT))

Build a model and implement kinetic parameters experimentally

measured to model experimental data

Kinetic modeling: global model

A tunedE 101784 (exp)

Model

Exp heating

Exp cooling

Inlet gas temperature (°C)

CH

4 con

vers

ion

(%

)

Simple mixture: CH4 + O2

r= k [CH4]α [O2]β

k=A exp(-Eact/(RT))

Acknowledgments

Swedish Energy agency (FFI 37179-1) is greatfully acknowledged for the financial support.