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1
Experience with SCR Technology for Diesel Exhaust Emission Control of Trucks in Asia,
Europe and North America
Gary Keefe and Raimund Mueller
Bangkok, February 1, 2001
Motivation for Diesel Engine Emission Control
Human health impact
Photochemical smogAcid rainHuman health impact
Human health impact
Greenhouse gas - climate change
Photochemical smog
EngineEmissions
HC
NOx
PM
CO
CO2
2
Why Reducing Nitrogen Oxides?
NitrogenDioxide(NO2)
from the Exhaust Gas
Ozone forms and is inhaled by persons
Sun effect
NitrogenMonoxide
(NO)
AtomicOxigen (O)
MolecularOxigen(O2)
SCR Reactions with Reducing Agent -Urea
Hydrolysis-Reaction:(NH2) 2CO + H2O 2 NH3 + CO2
SCR-Reaction:
4 NH3 + 4 NO + O2 4 N2 + 6 H2O
8 NH3 + 6 NO2 7 N2 + 12 H2O
3
Applications of SINOx Catalysts and Systems
Power Plant Truck
Greenhouse Fertilizer/CoGen
Incinerator
Marine Propulsion
Railroad Engine
Diesel Car
Stationary Diesel
SINOx®-Catalysts
Future Emission Standards for Commercial Vehicles and Market Requirements
Source: Moser et. al.NOx - g/kWh
0190
200
210
220
230
1 2 3 4 5 6 7
Marketrequirement
Legislativerequirement(NOx)
Trade -off with currenttechnology (EU3/US 98)
BSF
C -
g/kW
h
0
0,1
0,2
0,3
0,4
Part
icul
ates
-g/
kWh 2007
2004/2005
2008
1998/2000EUUS
J
Worldwide exhaust emission standards for HD diesel engines beyond 2000
4
Exhaust Emission Control Motivation: Diesel Trade-Off
NOx-Emissions [g/kWh]
98632100
1074 5
0,04
0,06
0,08
0,1
0,12
0,14
0,16
0,18
PM-E
mis
sion
s [g
/kW
h]
0,02
NOx/PMDPF
EGR &Combustion
SINOx
Engine(PM-opt)
NOx/BE
Spec
ific
Fuel
Con
sum
ptio
n[g
/kW
h]Emissions-Reduction Potential with SINOx System
Increase of engine-out NOx emission due to fuel efficient tuning, for lowPM emission
Improvement of BSFC over EURO 3 engineattainable
Emission data in g/kWh
BSFC0
20
40
60
80
100
120
140
160
180
200
NOx HC PM
Rel
ativ
e Em
issi
on in
%
E
5
9
1,8
0,660,6
0,12
0,1
0,03
0,02
80% NOx-reduction
80% HC-reduction
30% PM-reduction
SINOx Capability EURO 3 EnginePM & BSFC optimized engineOptimized engine w/ SINOx
5
The SINOx® System for Trucks
• Urea Dosing Unit,Urea and Diesel tankintegrated in one unit
• SCR-catalyst integratedin series silencer
• base-metal catalyst• ceramic monolith• cat.volume 30 ltr.• 200 cpsi
• 12 l HD-Diesel engines• 6-cylinder• 400 hp class
diagnosis
SCR-Catalyst
NOx, O2
reducingagent
(NH2) 2CO
purifiedexhaust
N2, H2O
Urea-Dosing Unit
exhaust
operating
data
(NH2) 2COEDC
ECU DCU
engine
Characteristics of SINOx SCR Systems
Active emission control system• integrated solution - „Not just an Add-on“• communication between engine and urea dosing unit via CAN bus• integration into the vehicle infrastructure (pressurized air, electrics)
Resources• Diesel fuel with S < 0,15%• 32,5% solution of urea as reducing agent
• Temperature range of exhaust: gas 200...550°C (without oxidation catalyst)• no or slight increase of exhaust backpressure compared to standard silencer• combination with particulate filter feasible if desired for special applications
Function
6
Urea distribution infrastructure conceptIndustry Committee established with members including oilindustry, vehicle and engine manufacturers ureamanufacturers and Siemens:
Step 1- Refilling urea at truck home yard Step 2 - Refilling urea at main truck stops located
along the major highwaysStep 3 - Refilling urea at the gas stations Urea Pump Station
Urea Charateristics:
• non-hazardous, non-explosive, non-toxic• released as a food-additive• lowest water polluting classification
Reducing Agent Aqueous Urea
Urea - Applications
UREA
Agriculture• fertilizer• feed
Water industry• nutritive substance forthe biologicaltreatment of wastewater
Power industry
• reducing agent for exhaust gas
Chemical Industryraw material for:
• UF-resins• Urethanes• and many others Food processing
• for chewing gum production
Medical and pharmaceutics for the production of:
• barbiturates• diuretics• special injury bandages
Other industriesauxiliaries in:
• chipboard industry• textile industry• coolant lindustry• cosmetics industry
There is no shortageof urea
7
SINOx® System - Field Demonstration
Total mileage: 21 trucks 6.099.000 kmMax. mileage of single vehicles: 524.000 km
(Status: 2000-03-27*)
*) 2nd road test finished 1999-12-31. Some vehicles are operated further for long term testing
Measurements
Investigations:
• on the road (vehicle): NOx-reductionUrea consumptionmechanical durability
• in lab reactor (SCR-catalyst): activity (NOx-reduction) = f (mileage)physico-chemical measurements(surface area, composition, etc.)
• on the test bench (silencer): NOx-reduction at start (ESC, ETC)NOx-reduction at end (ESC, ETC)
8
0
0,004
0,008
0,012
0,016
0,02
PM [g
/kW
h]
total PM soluable insoluable0
0,004
0,008
0,012
0,016
0,02
PM [g
/kW
h]
total PM soluable insoluable
PM and NOx emissions - ESC test w/12 ltr. HDE + SINOx
0
2
4
6
8
10
12
NO
x [g
/kW
h]NOx
Engine out emissions after SINOxEngine out emissions after SINOx
- 81%
PM and NOx Emissions - ETC test w/12 ltr. HDE+ SINOx
0
0,004
0,008
0,012
0,016
0,02
0,024
PM [g
/kW
h]
total PM soluable insoluable0
2
4
6
8
10
12
NO
x [g
/kW
h]
NOx
Engine out emissions after SINOx
0
0,004
0,008
0,012
0,016
0,02
0,024
PM [g
/kW
h]
total PM soluable insoluable
- 86%
9
On-board NOx-measurement on mixed highway
Time in seconds
Highway Section Bamberg RedwitzN
Ox-
Con
cent
ratio
n in
ppm
0
200
400
600
800
1000
1200
1400
1600
1800
2000
0 750 1500 2250 3000
NOx conversion: 71.2 %NOx conversion: 71.2 % NOx before Cat.
NOx after Cat.
NOx before Cat.
NOx after Cat.
Results of Measurements
Measurements were done and reported by TÜV Automotive, Germany
1st demonstration program: 0 km 130,000 km remark
NOx reduction on-road: 56% 54% constant within accurarcy
Urea consumption fleet average 4.1 % of diesel fuel consumption
2nd demonstration program: 0 km 272,000 km remark
NOx reduction ESC cycle: 65% 63% constant within accurarcy
NOx reduction ETC cycle: 70% 71% constant within accurarcy
NOx reduction on-road: 74% measured after 212,000 km
Urea consumption fleet average 5.5 % of diesel fuel consumption
10
Catalyst activity during field demonstration
•Catalyst Activity in accordance with predicted deterioration factor (over 500,000 km)•Catalyst total specific surface area and active materials constant over test program• Deposition of phoshate on catalyst surface in upstream face of catalyst
0.6
0.7
0.8
0.9
1
0 100 200 300 400 500 600
Driv ing Performance [1000 km]
NO
x C
on
vers
ion
Per
f. (
rel.)
SINOx® Catalyst
Fuel optimized engine meeting EURO 4/2 with SCR
• Engine modification to EURO III engine for best fuel economy (BSFC)
• NOx & PM Emission below EURO 4/2 in ESC and ETC
Program by VROM, AVL, Deutz, Siemens (Source: AVL, Cartellieri et. al. )
0,0
2,0
4,0
6,0
8,0
10,0
12,0
Baseline Optimized w /SCR EUROIV/1
w/SCR EUROIV/2
NO
x,
PM
* 1
00
in
g/k
Wh
180
185
190
195
200
205
210
215
220
225
BS
FC
in
g/k
Wh
NOx
PM * 100
BSFC
11
US truck SCR investigation & demonstration program
-100%-80%-60%-40%-20%
0%20%40%60%80%
100%
emis
sion
s ch
ange
(%)
NOx HC PM CO CO2
cold US-transient hot US-transient OICA
0,00,10,20,30,40,50,60,70,80,91,0
amm
onia
slip
(ppm
avg
)
NH3
US SCR HD Truck Demonstration Program
12
Applying NOx Sensors
0
400
800
1200
1600
0 1 2 3 4 5
NOx sensor output in MV
NO
x (p
pm)
Linear correlation between chemiluminescent analyzer and NOx sensor
NOx sensors upstream and downstream of catalyst accurate
0
300
600
900
1200
1500
0 60 120 180 240 300 360
time (s)
NO
x (p
pm)
SCR OFFbefore catalyst
after catalyst
On-road SCR emission reduction measured w/ NOx Sensors
0
300
600
900
1200
1500
0 60 120 180 240 300 360time (s)
NO
x (p
pm)
Level highway: 77 %Mountain highway 71 %
Urban traffic: 78 %
Overall average: 73 %
----- before catalyst ---- after catalyst
13
Experience with SCR in Asia
SCR included in Japan Clean Air Program (JCAP) technology assessment - results will be published later this year
Japanese diesel engine and truck manufacturers operate SINOx SCR systems in test cells and trucks
SCR Experience in Japan, Taiwan, South Korea in utilitypower plants, gas turbines and Stationary diesels since the1970s
NOx Reduction in Japanese 13 mode Cycle with Japanese Diesel HD Engine
0
500
1000
1500
2000
2500
3000
1 2 3 4 5 6 7 8 9 10 11 12 130
5
10
15
20
25
30NOx without SINOx: 10.4 g/kWh
NOx with SINOx: 3.0 g/kWh
NH3 ppm
NOx-Reduction: 71 %
NO
x g/
h
NH
3 pp
m
Mode No.
14
Monitoring and Diagnosis
• NOx sensors have been demonstrated as applicable technology.
• Upon commercial availablity and proven long-term durablity NOx sensors
• can be useful tool for:
+ Monitoring Diagnosis Control
• Sensors monitor operation and functionality of system components
• Sensors monitor level and quality/grade of reducing agent
• System control unit collects and interprets sensor data
• System control unit transfers information to engine control unit for further evaluation
SCR Trucks becoming available
Field demonstration has proven:
SCR-systems reduce NOx, HC, PM emissions in test cycles and in real world operation
SCR is a viable technology for trucks
SCR durability in accordance with truck operation
What‘s next:
SCR trucks offered by OEMstarting in 2001 2001
15
Customer‘ s benefits using SINOx
• Savings in emission-staged road-pricing - those will be implemented according to Government decisions in several European Countries 2003
• Meeting NOx limits of the two steps Euro 4/1 & 4/2 with the same technologywith fuel efficient Eu 2 engines, lowest PM by adjusted engine tuning & advanced design
• Insensitive to fuel sulfur - operation with current standard fuel (500 ppm S)Truck operation outside central Europe or US with low grade diesel fuel also possible
• Proven longterm stability and durability (> 500,000 km)
• Catalyst system performance is demonstrated to be constant within measurement accuracy
• Flow-Through system, truck mobility not at risk