Download - Bio 3B: Biodiesel exhaust aftertreatment
Presented by the
National Biodiesel Board
Biodiesel Technical Training Course
BIO3B: Exhaust A:er-‐
Treatment and Biodiesel
Today’s Topics
• Changes in diesel engine emissions regula4ons • Basics of diesel engine emissions
– Changes in hardware required by emissions regula4ons – Interac4ons of fuels and fuel systems
• Methods of exhaust a>ertreatment • Exhaust a>ertreatment & biodiesel • Resources
• Provide access to industry experts for more detailed ques4ons and answers about biodiesel
• Introduce the Na4onal Biodiesel Board’s Diesel Technician Training program and the program resources to the audience
• Provide quality informa4on about biodiesel and diesel emissions
• Provide quality informa4on about biodiesel usage and today’s diesel exhaust emissions a>ertreatment
Learning Objec4ves
• Be able to answer general questions about biodiesel that you may be asked as a technician
• Be able to answer questions about biodiesel emissions • Be able to answer questions about biodiesel usage and
today’s diesel exhaust emissions aftertreatment • Be able to make recommendations regarding biodiesel use
and vehicle maintenance
Learning Outcomes
US On Highway Emissions Standards
1988 1990
1991 1994
1998 2000
2002
2010 0.80
0.33 0.134 0
2
4 6
8
10
12
NO
x, g/
kW-H
r
8.05 6.7 6.7
5.4
3.3
1.5
0.013
14
16 14.4
2007
0.27
Diesel Emission Reduc4ons
Fuel technology
Combustion technology
Aftertreatment technology
Fuel system technology
Better understanding of combustion
Alternate Fuels (Biodiesel) Low sulfur De-NOx
DOC
PM trap
Rate control High pressure Multi-injection
EGR technology Others
Control technology
Emission Reduction in Diesel Engines
Exhaust & Emissions Controls
• EGR: Exhaust Gas Recircula4on • Cataly4c converters • DPF: Diesel Par4culate Filters • DOC: Diesel Oxida4on Catalyst • SCR: Selective Catalytic Reduction (Urea) • Emissions regula4ons dicta4ng changing engine and fuel injec4on design
2010 standards
• Introduction of ultra-low sulfur diesel fuel in October 2006
• EPA emissions standard for 2007: • Diesel particle filters (DPF) • Increased levels of exhaust gas recirculation (EGR) and higher fuel
injection pressures
• Full EPA emissions standard in 2010: • DPF, EGR, high pressure fuel injection
• Exhaust catalysts for NOx reduction • NOx adsorber catalysts, unburned diesel fuel for operation
• Selective catalytic reduction (SCR) • Diesel Exhaust Fluid (DEF) needed for SCR operation
Diesel Par4cle Filters
• Exhaust flows through porous wall-‐flow elements – PM is trapped on the walls of the filter
• When exhaust temperature is high enough, PM is burned off – In most cases, unburned diesel fuel is injected to accomplish this
• Precious metal is loaded onto filter walls to lower the temperature required for regenera4on
• Issues: – Regenera4on at low temperatures/duty cycles – Plugging with incombus4ble materials like lube oil ash
Diesel Par4culate Filter (DPF) Maintenance
• Carbon par?culates are burned off with on-‐board regenera?on
• Ash remains in the DPF and must be removed periodically – This requires removal from vehicle
Catalyzed Diesel Par4culate Filter (CDPFs)
• Uses chemicals in exhaust to con?nuously burn carbon in Soot Filter
• Must s?ll be removed to clean ash
NO2 Oxidizes Soot in Filter 2NO2 + C CO2 + 2NO
Converts NO 2NO2
Soot Filter Platinum Catalyst
Exhaust Gas
DPF Regenera4on
SCR Performance
Biodiesel Tes4ng
Cummins ISB 300 • 2002 Engine, 2004 Certification • Cooled EGR, VGT Johnson Matthey CCRT • 12 Liter DPF • Passively Regenerated System • Pre Catalyst (NO2 Production)
• Fuels: ULSD, B100, B20, B5
• ReFUEL Test Facility • 400 HP Dynamometer • Transient & Steady State Testing • Cummins • Soot Characterization • Significant financial support for testing
B20 results in substantial PM reduction even with DPF (data for 2003 Cummins ISB with Johnson Matthey CCRT on HD FTP)
B20 Testing
Reduction with DPF ranges from 20% to 70%, depending on basefuel, test cycle, and other factors • Reduction in sulfate emissions • Increased PM reactivity
Williams, et al., “Effect of Biodiesel Blends on Diesel Particulate Filter Performance” SAE 2006-01-3280
Superb Results BPT
ULSD 360ºC B20 320ºC B100 250ºC
• BPT is 40ºC lower for B20 • Soot is more easily burned off of filter • B20 can be used for lower temperature duty cycle
• Regeneration rate increases with increasing biodiesel content
• Even at 5%, biodiesel PM measurably oxidizes more quickly
NOx Adsorber Technology
• Filter removes par?cles • LNA absorbs NOx on lean opera?on • Controls switch to rich opera?on to NOx to harmless Nitrogen • Filter regenera?on and LNA regenera?on are separate • Complex; costly; & fuel economy loss
Filter
Diesel Injector
NOx Sensor
DOC Valves
DOC
Diesel Oxidation Catalyst
LNA
Bypass Reference: Volvo
SCR Performance
NOx Controls
• NOx Adsorber Catalyst/Lean NOx trap – Catalyst converts all NOx to NO2, adsorbent bed “traps” NO2
– When bed is saturated, exhaust forced rich – NO2 is released and converted to N2 – Bed also traps SO2, but doesn’t release it
• Near sulfur free exhaust is needed • Higher temps, longer 4me needed to release sulfur
– 90%+ conversion is possible
• Selec4ve Cataly4c Reduc4on (SCR) – Used for industrial NOx control for years – Requires a supplemental “reductant” – Typically ammonia, derived from urea
• “Diesel Exhaust Fluid” – 80-‐90% reduc4on efficiency – Generally sulfur tolerant
NOx adsorber catalyst (NAC) is also known as a lean-NOx trap (LNT)
SCR
NO
x +
NH
3 Se
nsor
Ure
a In
ject
ion
Biodiesel Tes4ng with LD Emission Systems
• Includes two emission control systems and two fuel blends on a light-‐duty placorm – NAC/DPF and SCR/DPF – 5% and 20 % biodiesel blends
• Performance, op4miza4on and durability – Aging to represent 2100 hours of opera4on (approximately 120,00 miles or
full useful life) for B20 – Emissions evalua4ons over UDDS, US06, and HFET– tes4ng by EPA – Perform engine and fuel component teardown at end of aging
Engine: DCX OM646
Vehicle: Mercedes C200 CDI
ULSD vs B20 – SCR
No statistical difference in NOx Conversion with B20
Selec4ve-‐Catalysts Reduc4on (SCR) Aqueous Urea Solution Tank
Ammonia Slip
Catalyst Engine
1 2
3 4
5 6
T
Air Induction
Pump and Injector
Atomized Urea
Solution
Catalyzed Particulate
Filter
SCR Catalyst
Air to Air Cooler C
Reference: DDC
Turbo-Charge
NO EGR
Selec4ve-‐Catalysts Reduc4on (SCR)
• Uses aqueous Urea instead of fuel to convert NOx to Nitrogen – Requires extra tank etc. – Must add Urea distribu?on system to supply chain
• Reduced EGR or no EGR • Fuel economy gains compared to NOx Adsorber • Proven durability for European applica?ons • Favored by some for large truck and sta?onary applica?ons
How Does Biodiesel Effect Emissions & A>ertreatment ?
• Fuel System – Concern over deposits and corrosion – Addressed by ASTM specifica?ons
• Engine Emissions – Lower HC and Par?culate – NOx emissions depend on duty cycle
• A:ertreatment hardware / durability – Easier DPF regenera?on – Studies at NREL / ORNL show no adverse effects on hardware
durability
What Will Be in the Marketplace? • All of the above! • Par?culate Traps (or Soot Filters) were across the board in 2007
• NOx Adsorbers are on some pick-‐up truck applica?ons
• SCR is favored for many HD truck and sta?onary applica?ons
Biodiesel and A>ertreatment Systems
Biodiesel is compa4ble with Diesel Par4culate Filters, and has some dis4nct advantages: • Lowers regenera4on temperatures • Less engine out par4culate maher • May provide increased performance and decreased maintenance vs. ULSD alone
• May provide increased fuel economy
Regenera4on mode is important • Late in-‐cylinder injec4on may cause increased fuel dilu4on of engine oil and limit the level of biodiesel that can be used (i.e. B20 or B5)
• Most US heavy duty applica4ons use exhaust stream fuel injec4on which is compa4ble with B20, perhaps higher blends
• Some light duty OEMs recommend max B5 at present
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Conclusion
• NBB, the US Department of Energy, and the engine and vehicle manufacturers are expending significant resources to understand how biodiesel blends interact with new diesel emission controls
• Detailed tes4ng thus far indicates B20 and lower blends are compa4ble with both diesel and NOx a>er treatment – Provides benefits in some cases
• B5 is now just part of normal D975 diesel fuel • Addi4onal study is underway
– Quan4fy long term benefits of biodiesel blends – Late in-‐cylinder injec4on impact on fuel dilu4on – NBB is encouraging OEM’s to publicly support B20
Biodiesel Resources
www.biodiesel.org • Biodiesel Training Toolkit • News Releases & Informa4on Resources
• Technical Library, Spec Sheets & Videos • OEM Warranty Posi4ons on Biodiesel
• U.S. Diesel Vehicle List
www.BQ-‐9000.org • Lis4ng of BQ-‐9000 Cer4fied Companies
www.biotrucker.com • Lis4ng of BioTrucker retail sites
www.biodieselautomo?ve.org • Dedicated to information exchange for biodiesel & diesel technicians
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Thank You! Questions…?
Rachel Burton OEM Diesel Technician Training Program [email protected] Tel: 919-‐444-‐3495
Call NBB at 1-‐800-‐841-‐5849 Visit www.biodiesel.org
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