retrofit emission control technologies for heavy duty diesel engines - the state of the art sougato...
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RETROFIT EMISSION CONTROL RETROFIT EMISSION CONTROL TECHNOLOGIES FOR HEAVY DUTY TECHNOLOGIES FOR HEAVY DUTY
DIESEL ENGINES - THE STATE OF THE DIESEL ENGINES - THE STATE OF THE ARTART
Sougato Chatterjee Johnson Matthey Catalysts
BAQ 2004
Outline
• Diesel Engine Emissions
• PM Control Technologies
• NOx Control Technologies
• Conclusions
Diesel Engine Emission Control
• Diesel engine emissions:– PM (Particle Matter)– NOx (Nitrogen Oxides)– CO (Carbon Monoxide)– HC (Hydrocarbons)
• New engine emissions are being significantly reduced with increasingly tighter emission standards
• However, some of the existing, high-emitting diesel engines will be in use for the next 10 to 25 years
• Using emission control technologies to produce extremely clean new engines as well as to retrofit existing engines is the way to reduce emissions
Schematic of Diesel Particles and Vapor Phase Compounds
Reprinted with Permission from SAE paper no. 940233 C 1994 Society of Automotive Engineers, Inc.Reprinted with Permission from SAE paper no. 940233 C 1994 Society of Automotive Engineers, Inc.
Vapor Phase Vapor Phase HydrocarbonsHydrocarbons
Sulfate (SOSulfate (SO44))
Adsorbed HydrocarbonsAdsorbed Hydrocarbons
Soluble Organic Soluble Organic Fraction (SOF)/Fraction (SOF)/Particle Phase Particle Phase HydrocarbonsHydrocarbons
Solids Solids (SOL)(SOL)
Solid Carbon Spheres (0.01 - Solid Carbon Spheres (0.01 - 0.08 mm diameter) combine to 0.08 mm diameter) combine to make Particle Agglomerates make Particle Agglomerates (0.05 - 1.0 mm diameter with (0.05 - 1.0 mm diameter with Adsorbed HydrocarbonsAdsorbed Hydrocarbons
Adsorbed HydrocarbonsAdsorbed Hydrocarbons
Liquid Condensed Liquid Condensed Hydrocarbon ParticlesHydrocarbon Particles
Sulfate with HydrationSulfate with Hydration
17179701
Outline
• Diesel Engine Emissions
• PM Control Technologies
– DOC technology
– DPF technology
– Fuel Sulfur Effect
– Advanced DPF technology
– Active Regeneration Filter Technology
– Partial Filter technology
• NOx Control Technologies
• Conclusions
Diesel Oxidation Catalyst
Diesel Oxidation Catalysts (DOC)
• Oxidizes CO and HC to CO2 and H2O (desired)
• Oxidizes toxics such as aldehydes
• Oxidizes SO2 to SO3 (undesired)
• Oxidizes Soluble organic fraction (SOF, HCs) adsorbed on Particulates to reduce PM
• CO, HC reduction up to 90%.
• PM reduction up to 50% depending on SOF content of PM; Typically 25% on new engines
Ceramic Catalyst
DOC in a muffler
Particulate Matter Oxidation
CarbonSoot
Catalyst
CarbonSoot
Note: Soluble Fraction,Sulfates and Water are in Vapor form.
DOC - Applications
• Can work with high sulfur fuel (up to 500 ppm)• Benefits from low S fuel (low sulfate make)• Can activate at lower temperature for CO & HC
reductions • Proven low-cost technology• Combined catalyst and muffler to provide sound
attenuation and emission benefit• Easy to retrofit on existing vehicles
– 2 stroke & 4 stroke• No required maintenance• Variety of sizes and shapes for different applications
DOC Performance 500 PPM S Fuel
PM(g/bhp-
hr) Reduction
CO(g/bhp-
hr) Reduction
HC(g/bhp-
hr) Reduction2-Stroke
Baseline 0.44 1.0 0.7
W/ CEM 0.22 50% 0.6 40% 0.4 43%
4-Stroke
Baseline 0.073 1.11 0.115
W/ CEM 0.055 25% 0.35 68% 0.014 88%
Tested at Southwest Research InstituteunderEPA approved FTP transient test cycle
DOC Performance on BEST EURO II Bus500 ppm S Fuel
0
0.5
1
1.5
2
2.5
3
CO HC NOx/10 PM
Em
iss
ion
s (
g/k
m)
Base Engine Emissions
Engine with DOC
27%
Diesel Particulate Filter
Diesel Particulate Filter • Johnson Matthey Continuously Regenerating
Technology (CRT®) Diesel Particulate Filter
CRT® Particulate Filter for >90% PM Removal
• Patented CO/HC/PM Emission Control System combining Oxidation Catalyst & Filter
• Engineered as a totally passive emission control system which requires no supplemental heat
• Uses NO2 produced by a specially formulated catalyst to burn soot collected by the filter at typical operating temperatures of diesel engine exhaust
• Requires the use of Ultra Low Sulfur fuel (< 50 ppm S) for maximum emission reduction and filter regeneration
CRT® Particulate Filter – Operating Principle
Examples of CRT Installations in the US
Mumbai Transit (BEST) Hino Engine Euro II Bus with CRT
Avg. Emissions Test Results- CRT vs. CNG LA MTA Data – Ser 50 Engines - CBD Cycle
0.0
1
2.9
1
0.0
2
0.1
7
0.0
1
3.5
2
0.1
7
0.0
07
12.01
1.5
2
1.1
8
0.0
09
0
1
2
3
4
5
PM CO/10 THC NOx/10
Em
issi
on
(g
/mil
e)
CRT w/ ECD
CRT w/ ECD-1
CNG
Carbonyl Destruction with CRT on Ser 50 under NY Bus Cycle
181
89
17
287
0.83 0.75 1.83 3.4
2551
42
16
2609
0
50
100
150
200
250
300
Formaldehyde Acetaldehyde Acetone Total Carbonyls
Em
issi
on
s (m
g/m
i)
OE w/ Std. Diesel
CRT w/ ULSD
CNG
Fuel Sulfur Effect on Diesel Particulate Filter
Impact of Fuel Sulfur• Impact of Fuel Sulfur on CRT Regeneration
• Catalyst can be poisoned by high sulfur in fuel • Lower NO2 generation; Problem in filter regeneration
• Impact of Fuel Sulfur on CRT Particulate Emissions• High SO2 oxidation, so sulfate can increase measured PM • Low PM reduction (40 – 50%) due to high sulfate make
Impact of Fuel S on Emissions350 ppm vs. 15 ppm fuel with CRT under FTP
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.1
BSHC BSNOx/100 BSCO/10 BSPM
Em
iss
ion
s (
g/b
hp
-hr)
Base Engine with LSD
CRT with LSD
Base Engine with ULSD
CRTwith ULSD
CCRT™ - Advanced Passive Filter System
CCRT™ – An Advanced CRT for Challenging Applications
• CCRT = DOC + Catalyzed Filter
• Advantages of CCRT:– Higher soot burn rate than CRT or CSF
• Install in Challenging Applications– Low temperature applications (200 – 250oC)– Low NOx/PM applications (NOx/PM>15)
• Even at low CSF loadings, we see improved performance with the CCRT
• Successfully demonstrated in field trials in the US, Europe and Asia
Use of NOx Within CCRT System
CCRT Experience on low temperature School BusBoston School Bus with 175 hp 2000 MY CAT 3126 Engine
Daily Pressures on
-1
0
1
2
3
4
5
6
12/3
0
1/30
2/28
3/30
4/30
5/30
6/30
7/30
8/30
9/30
10/3
0
11/3
0
12/3
0
1/30
2/29
3/30
4/30
Date
Bac
K P
ress
ure
(in
Hg
)
Max Pres Avg Max Pres Avg Pres
To
Boston School Bus 00630-Dec-02 14-May-04
Temperature Distribution
0
250
500
750
1000
1250
1500
1750
2000
2250
2500
100
125
150
175
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
Exhaust Bins (C)
Fre
qu
ency
(A
bso
lute
)
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Tim
e o
ver
tem
p (
%)
Frequency
%Time Above Temp
To
Boston School Bus 00630-Dec-02 14-May-04
•Cold Exhaust Temperature Profile
•Only 8% of time Temp > 260 C; 40% time @ 200 C
•CCRT operating with stable back pressure for over 17 months
Active Regeneration: Low NOx/PM applications
Active Regeneration with Fuel Injection
Courtesy:
Exhaust back pressure
Temperatures
After catalystBefore catalyst
3 hours
140 mbar
Active Regeneration of CRT with Fuel Injection System
Courtesy:
Partial Filter Systems
Partial Filter Product Development
•Partial filtration = moderate (>50%) PM reduction, but minimize filter plugging
–Some PM is trapped, rest goes through
•Use variety of substrates:–Flow through with notches –Wire mesh –Ceramic foam
•Can use in CRT or CCRT configuration for effective soot burn
•Ideally suited for old, dirty engine retrofit–America, Asia
• Work with ULSD proven; Tests in progress with LSD fuel
Step to filtration activity:
porous layer made of sintered metal fiber fleece
Partial Filter Product Development
Trash Truck in CA with Partial Filter
Clean outlet head on partial filter after operation
Emissions Results for Partial Filter SystemCaterpillar 3126 MY 1998, under US FTP Transient cycle
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
PM*10 CO/10 HC Nox/10
Em
issi
on
s (g
/bh
p-h
r)
Engine Out
Engine + PFT
Outline
• Diesel Engine Emissions
• PM Control Technologies
– Fuel Sulfur Effect
• NOx Control Technologies
– EGRT
– SCRT
• Conclusions
EGRT Development & Applications
EGRT™ System• EGRT™ = EGR + CRT®
• CRT = Continuously Regenerating Technology Diesel Particulate Filter
• EGR = Re-circulation of part of the exhaust gas to engine intake air
• Uses STT patented EGR technology in combination with the CRT particulate filter
• ULSD (< 50 ppm) fuel is required
EGRT System and Throttle Valve
Intake Air In
Cooled Exhaust In
EGRT Retrofit on VTA Transit Bus
Emissions Results for EGRT SystemCummins ISL 330 Engine, FTP Cycle on Engine Dyno
0.16
0.38
0.07
0.43
0.03
0.17 0.19
0.00 0.
05
0.00
0.17 0.20
0.06
0.69
0.10
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
FE/1000 NOx/10 THC CO PM
Em
issi
ons
(g/b
hp-h
r)
Baseline (Engine w/ DOC)
w/ EGRT
w/ EGR & OE DOC (no filter)
Selective Catalytic Reduction (SCR)
SCR and SCRTTM System Schematics
Engine
SCR Oxidation Cat
Removal of NOX
Removal of NH3 slip if requiredRemoves CO and some HC’sand PM SOF
1 to 3 way conversion
Urea
Engine
CRT SCR Oxidation Cat
Removal of HC, CO, PMNONO2
Removal of NOX
Removal of NH3 slip if required
4-way conversion
UreaSCR
SCRTTM System
• SCRT = SCR + CRT• System Components
– CRT system– Urea Injection system– SCR system
Retrofit SCRT System
SCRT Field Trial Bus in UK
London Bus – Millbrook Testing
82%
0%
81% 84% 89% 87%
0%
86% 79%
89% 84%
0%
83% 82% 89%
0% 10% 20% 30% 40% 50% 60% 70% 80% 90%
100%
Setting 1 Setting 2 Setting 3 Setting 4 Setting 5
Outer London Inner London Combined Outer and inner London
NOx (g/bhp-hr)
Effect of Emission Control Retrofit on Current Engines
0.00
0.02
0.04
0.06
0.08
0.10
0 1 2 3 4 5 6 7 8
Par
ticu
late
Mat
ter
(g/b
hp
-hr)
1
2
Starting point1998 Engine
FEDERAL 2002 Oct.
4 3 CRT®
EGRT
DOC
SCRT®
5
Conclusions
• A multiplicity of catalytic emission control technologies now exists to aid the emissions engineer in achieving virtually zero emission levels from diesel engines
• Johnson Matthey provides a variety of PM and NOx control technologies for retrofit and OE applications– PM Control: DOC, CRT, CCRT, PF
– NOx Control: EGR, SCR and LNT
• DOC is a cost effective solution for use with 500 ppm S fuel
• Improved fuel quality especially ultra low sulfur fuel (< 50 ppm) enables the most advanced control strategies (CRT)
• Some engineering challenges remain for advanced system development, and overcoming infrastructure issues
Contacts:• Sougato Chatterjee • (610) 341-8316
WWW.matthey.com
Johnson Matthey India Pvt. Ltd.Plot No. 12, Sector 3IMT ManesarGurgaon – 122 050Haryana, INDIA+91 124 229 0234