O 2 - Energimyndigheten

Report
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, Sweden
3Scania CV AB, 151 87 Södertälje, Sweden
4AVL MTC Motortestcenter AB, Box 223, 13623, Haninge, Sweden
Methane Powered Heavy Duty Engine with Low Fuel Consumption
and Euro VI Emission Compliance
The target for this project proposal is to address the problem of combining low energyspecific 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
Compressed Natural Gas as vehicle fuel
• To decrease mineral oil consumption
• To decrease greenhouse gas and pollutants emissions
3
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)
4
Natural gas vehicles: worldwide count
Country
Natural Gas Vehicles
Refuelling Stations
Date
www.iangv.org
5
Catalyst preparation:
The catalyst contains 3.2 wt.% of Pd and 0.6 wt.% Pt on 20 wt.% Ce-Al2O3
Support: 20 wt.% Ce-Al2O3 (S = 114 m2/g) calcined in air at 900 oC, 2 h;
Ceramic monolith: 400 cpsi; l = 20 mm, d = 21 mm;
Washcoat: 500 mg calcined in air, 600 oC, 2 h
Catalytic activity measurement:
Pre-treatment
Ramp test
1. Reduction T = 500 oC; 2% H2; Ar; 30 min
2. Lean/rich/lean cycle T = 700 °C
700
Temperature (oC)
Pretreatment:
Lean: 0,03% CO; 0,05% NO; 0,05% CH4;
8% O2; 5% H2O; Ar; 60 min
2; 3
600
500
1
400
Rich: 2% H2; 5% H2O; Ar; 20 min
3. Ageing T = 700 C; 8% O2; 5% H2O; Ar; 30 min
300
200
Ramp test (Lean conditions):
100
0
0
60
120 180 240 300 360 420 480 540 600
Time (min)
Heating/cooling cycle
T = 150 - 700 oC; ramp = 5 °/min
6
Methane oxidation: simple gas composition
CH4 conversion (%)
100
Mixture: CH4 + O2
solid line - heating
dash line - cooling
75
without H2O
heating
cooling
Eact = 101 kJ/mol
Eact = 77 kJ/mol
50
25
3.2Pd-0.6Pt/Ce-Al2O3
0
200
250
300
350
400
450
o
500
550
600
Temperature ( C)
Conditions:
0.05% CH4; 8% O2; Ar
T = 150 - 700 oC; ramp = 5 °/min
Temperature of 50% conversion CH4, oC
Gas mixture
Heating
Cooling
CH4 + O2
329
305
24 oC
Methane oxidation: complex gas composition
CH4 conversion (%)
100
solid line - heating
dash line - cooling
Mixture: CH4 + O2 + CO + NO
75
without H2O
heating
cooling
Eact = 115 kJ/mol
Eact = 83 kJ/mol
50
25
Inhibiting effect of CO + NO:
-Increase of Eact
-Increase of T50
-Decrease of hysteresis amplitude
3.2Pd-0.6Pt/Ce-Al2O3
0
200
250
300
350
400
450
o
500
550
600
Temperature ( C)
Conditions:
0.05% CH4; 8% O2; 0.03% CO; 0.05% NO; Ar
T = 150 - 700 oC; ramp = 5 °/min
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
Reaction order calculation: complex gas composition
Conditions: without H2O; 0.05% CH4; 0.05% NO; 0.03% CO; 8% O2; Ar
T = 305 oC
O treatment
O treatment
2
CH4 conversion (%)
60
O2 treatment
700 - 305 oC
2
700 - 305 oC
700 - 305 oC
0 NO
O2 change
CH4 change
CO change
NO change
50
40
0 CO
30
0 CH4
100 ppm
20
0 O2
100 ppm
200 ppm
800 ppm
1400 ppm
0.14 %
12 %
1100 ppm
10
0
0
120
240
360
Reaction order
480
600
Time (min)
720
840
960
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
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
r= k [CH4]α [O2]β
k=A exp(-Eact/(RT))
A
E
tuned
101784 (exp)
CH4 conversion (%)
Simple mixture: CH4 + O2
Model
Exp heating
Exp cooling
Inlet gas temperature (°C)
Acknowledgments
Swedish Energy agency (FFI 37179-1) is
greatfully acknowledged for the financial support.

similar documents