diesel engines: emission control and biofuels · diesel engines: emission control and biofuels...
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Center for Diesel Research
Diesel engines: Emission control and biofuels
David Kittelson Center for Diesel Research
Department of Mechanical Engineering University of Minnesota
Tenth Annual
Freight and Logistics Symposium Four Points Sheraton, Minneapolis
December 1, 2006
Center for Diesel Research
Nanoparticle formation– In the engine– In the atmosphere
Fundamental studies– Kinetics of soot oxidation– Role of metals in Diesel
nanoparticle formation• C / Ce cluster
Engine, Fuel and Nanoparticle Research Center for Diesel Research
David B. Kittelson, Professor of Mechanical EngineeringDirector, Center for Diesel Research
Renewable fuels, biodiesel, ethanol, to reduce CO2 and ultrafine particles
Sensors for real time control of ultrafine particles and NOx
Center for Diesel Research
Outline
• Introduction • Biodiesel • Future fuels – DME?
Center for Diesel Research
Emissions standards are becoming much tighter worldwide making exhaust aftertreatment essential
Plot courtesy Tim Johnson, Corning
• US 2010 levels correspond to about 99% reduction in PM and 98% reduction in NOx
• 2007 prototypes are better than the PM standard by factors of 5 to 20
Center for Diesel Research
Diesel Emission Control Pathways
Courtesy: Tim Johnson, Corning
European light duty US heavy duty 2007 2010? European light duty US heavy duty 2007 2010?
• Catalysts used in advanced aftertreatment require ultra low sulfur fuel • As of October 1, 2006 nearly all on-road fuel must be below 15 ppm S - down from 500 ppm
Center for Diesel Research
Typical exhaust filters – Johnson-Matthey CRT® and CCRT®
• Most PM filtration systems being considered for 2007 are the wall flow type shown on the left. Without regeneration to oxidize soot these devices quickly plug.
• Catalyzed filtration systems like the J-M CRT® shown on the right reduce regeneration temperature by producing NO2 from exhaust NO in an oxidizing catalyst upstream of filter
• The J-M CCRT® has a catalyzed washcoat on the filter as well to further reduce regeneration temperature
• In most applications active regeneration is also required • NO2 in the exhaust is an issue
Figures courtesy Corning and Johnson-MattheyFigures courtesy Corning and Johnson-Matthey
Center for Diesel Research
Renewable Fuels for Engines
• Diesel engine fuels – Biodiesel – derived from vegetable oils, animal fats, recycled fats/oils,
oil producing algae – Fischer-Tropsch liquids – biomass gasification – Dimethyl Ether (DME) – biomass gasification – Ethanol – from corn, wheat, sugar by fermentation, cellulose digestion,
biomass gasification – Butanol – sugar?
• Gasoline engine fuels – Ethanol – from corn, wheat, sugar by fermentation, cellulose digestion,
biomass gasification – Biogas – anaerobic digestion of plant and animal waste – Fischer-Tropsch liquids – biomass gasification – Methanol – biomass gasification – Butanol – sugar?
Center for Diesel Research
Soy Methyl Ester (SME) Biodiesel Production
100 lbs. of soybean oil +
10 lbs. methanol =
100 lbs. soy biodiesel (B100)
+ 10 lbs. of glycerin
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Biodiesel Feedstocks
• Soybean Oil, SME (USA) • Rapeseed Oil, RME (EU) • Other vegetable oils (palm, sunflower,
corn) • Beef Tallow, pork lard • Recycled restaurant grease (yellow
grease), FAME
Center for Diesel Research
Biodiesel Blends
0 50 100
B2
B5
B10
B20
B100
Biodiesel Petroleum diesel
B100B100 = 100% b iod ie se l
B20B20 = 20% b iod ie se l + 80% pe trole um d ie se lB10B10 = 10% b iod ie se l + 90% pe trole um d ie se l
B5B5 = 5% b iod ie se l + 95% pe trole um d ie se l
B2B2 = 2% b iod ie se l + 98% pe trole um d ie se l
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Influence of Biodiesel on Diesel Emissions (Heavy-Duty)
US EPA 2002
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Influence of Biodiesel on PM Emissions (Heavy-Duty)– range of results
US EPA 2002
Center for Diesel Research
Feedstock has an Impact on Emissions
NOx Emissions PM Emissions
US EPA 2002
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Biodiesel Also Leads to Significant Decreases in Air Toxics
US EPA 2002
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Comparison between biodiesel and petroleum diesel • Little fuel consumption penalty • Considerable engine to engine variation in emissions
– Reduced emissions of HC, CO, and air toxics – NOx emissions vary – Sharply decreased soot emissions but increased volatile particle
emissions – Uncertain performance in advanced engines with aftertreatment
• Most manufacturers don’t recommend use of blends higher than B5 to B20 – Solvency – Cold flow – Oxidative stability
• Quality control and filter plugging still issues
Center for Diesel Research
”Well-to-wheel” analysis (Volvo study) Energy efficiency and Greenhouse gases Courtesy - Anders Röj, Volvo Technology Corporation, Fuels and Lubricants
Volvo Technology Corporation, Fuels and Lubricants
Future Fuels for Commercial Vehicles
”Well-to-wheel” analysis (Volvo study)Energy efficiency and Greenhouse gases
0%
10%
20%
30%
40%
Diesel
(crude o
il)
DME (natu
ral gas
)
MeOH (natu
ral gas
)
CNG (natu
ral gas
)
Syntheti
c dies
el (natu
ral gas
)
DME (wood, b
lack l
iquor)
MeOH (w
ood, blac
k liquor)
Biogas (s
ewag
e)
DME (wood)
MeOH (w
ood)
Syntheti
c dies
el (w
ood)
RME (rape s
eed)
Ethanol (w
ood)
Ethanol (w
heat)
0
250
500
750
1000
Energy efficiency, %GHG, g/kWh
g/kWh
Fossil Renewables
These figure include production, transport, and end use. Ethanol figures are based on European practice from wood or wheat
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What is DME?
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DME properties
• Physical properties similar to propane – LP gas • Nontoxic • DME is a gas at ambient conditions and unlike MTBE is
not a groundwater pollution threat • Uses
– Aerosol propellant in the cosmetic industry to replace CFC propellants
– Diesel fuel • High efficiency • Soot free combustion • Fuel system modifications required
– Fuel cell fuel – Propane replacement
• May be produced from natural gas or biomass
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Black liquor to engine fuels - Ideal use of low grade biomass Courtesy - Anders Röj, Volvo Technology Corporation, Fuels and Lubricants
Volvo Technology Corporation, Fuels and Lubricants
Future Fuels for Commercial Vehicles
Black liquor to engine fuels - Ideal use of low grade biomass
Pulp Mill
Green Liquor
Methanol/DME
Internal heat and powerBiomassfed power
boiler
BLGMF
AdditionalRenewable Energy
Pulp Wood
Pulp
Black Liquor
*
Production Efficiency = Methanol/ DMEAdditional Renewable Energy
> 65%*(Source:Chemrec)
Center for Diesel Research
DME/Methanol Production Potential
• From black liquor gasification using existing pulp mills – Total use of black liquor in the mill
• Finland 50% transportation fuels • Sweden 30% transportation fuels • Minnesota 4 – 7% transportation fuels
– Adding a small booster plant to existing Minnesota mill • 7 million gallons per year DME – enough for about 700 urban buses
(MSP metro fleet ~ 900) • Or 7 million gallons per year methanol – enough to supply all the
methanol needed by all Minnesota’s biodiesel plants (6.3 million gallons) with some left over
• Estimated cost $2.20-2.30 / gallon gasoline equivalent with no subsidies
• Chemrec are talking to mill owners in the MN / WI region about building such a plant. They are carrying out a conceptual study for one of them.
Center for Diesel Research
DME/Methanol Production Potential
• Using not just pulp mills but all readily available biomass sources – NREL estimates that Minnesota has available biomass streams
the could produce the equivalent of 100-200% current gasoline use via gasification
– This would require a number of large gasification plants but could be a very long term sustainable solution
– It is likely that different states will have a different mix of long term renewable energy solutions. We will no longer have monolithic petroleum
• A likely path to DME introduction will be initial use as a propane replacement followed by gradual introduction of DME vehicles
• Production of “green methanol” for use in biodiesel production and for fuel cells may also play a role
Center for Diesel Research
DME is an extremely clean Diesel fuel Second generation DME fueled truck from Volvo Courtesy - Anders Röj, Volvo Technology Corporation, Fuels and Lubricants
20042004
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Technology roadmap - DME Courtesy - Anders Röj, Volvo Technology Corporation, Fuels and Lubricants
Volvo Technology Corporation, Fuels and Lubricants
Future Fuels for Commercial Vehicles
Vehicle deliveryProduction proj.
2002 2003 2004 2005 2006 2007 2008 2009 2010
External influences
Fuel productiondevelopment
Engine and vehicledevelopment
Piteå (BLG)
US02 EU4 US07 EU5Tier3EU4i US10
AFFORHD (FM9 truck)
Buss Demo Gen2
Field Test (3 trucks)
DME combustion res.
Vehicle start
RENEW (SP3)
Vehicles start
Vehicles start
Combustion system for Large Field Test
Bio DME project Fuel deliveryP
P
Large Field Test (circa 30 HD vehicles)
Vehicle start
Technology Roadmap - DME Issue: 2005
DME NOx EATS research
Växjö Värnamo Biomass Gasification Center
- - - - -Planned
Decided
Center for Diesel Research
Renewable Fuels for Diesels
• Biodiesel is a near term solution – No significant changes to engine – Clean – Cost effective – High energy efficiency of production and modest greenhouse gas emissions – Potential to replace up to 30% of petroleum diesel
• Ethanol may play a role if ignition problems can be solved • DME is a strong candidate for a longer term future fuel.
– Requires substantial engine modification, mainly to fuel system – Best well-to-wheel energy efficiency from bio source, 25% better than synthetic
diesel (Fischer-Tropsch) – Close to CO2 neutral if produced from biomass – Highest efficiency, lowest GWP and cost of the biomass to liquid (BTL) fuels – Very low exhaust emissions (soot-free combustion, Euro 5) – Energy dense and liquid at low pressure – Non-toxic, biodegradable and harmless to the atmosphere
Center for Diesel Research
Hybrid vehicle concepts
• Parallel - engine and electric motor generator work in parallel. – Usually large engine – Relatively small electric motor – Honda Insight, Civic
• Series – engine drive generator, electric motor drives wheels. – Must have full performance electric drive. – May have smaller engine. – Most suited to plug in hybrid – Close relative of electric vehicle
• Series-parallel – combination of above. – Toyota Prius, Ford Escape
• Other hybrid types use hydraulic and flywheel energy storage – Electric hybrid, high energy density, low power density
• Long range – with large battery may be plug in • Limited power for acceleration, braking
– Hydraulic hybrid, high power density, low energy density • Good for local start stop • Effective regenerative braking
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Types of plug in hybrid vehicles Parallel
From: http//www.hybridcenter.org
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Types of plug in hybrid vehicles Series
From: http//www.hybridcenter.org
Center for Diesel Research
Types of plug in hybrid vehicles Series-Parallel
From: http//www.hybridcenter.org