Diesel engines: Emission control and biofuels

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Diesel enginesEmission control and biofuels

• David KittelsonCenter for Diesel
  ResearchDepartment of Mechanical
  EngineeringUniversity of Minnesota
• Tenth Annual
• Freight and Logistics Symposium
• Four Points Sheraton, Minneapolis
• December 1, 2006

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(No Transcript)
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Outline

• Introduction
• Biodiesel
• Future fuels DME?

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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

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Diesel Emission Control Pathways

• 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

Courtesy Tim Johnson, Corning
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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

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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?

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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

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Biodiesel Blends
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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
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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 dont recommend use of blends
  higher than B5 to B20
• Solvency
• Cold flow
• Oxidative stability
• Quality control and filter plugging still issues

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Well-to-wheel analysis (Volvo study)Energy
efficiency and Greenhouse gasesCourtesy - Anders
Röj, Volvo Technology Corporation, Fuels and
Lubricants
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 biomassCourtesy - Anders Röj, Volvo
Technology Corporation, Fuels and Lubricants
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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
  Minnesotas 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.

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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

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DME is an extremely clean Diesel fuel Second
generation DME fueled truck from Volvo Courtesy
- Anders Röj, Volvo Technology Corporation, Fuels
and Lubricants
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Technology roadmap - DME Courtesy - Anders Röj,
Volvo Technology Corporation, Fuels and Lubricants
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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

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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 vehiclesParallel
From http//www.hybridcenter.org
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Types of plug in hybrid vehiclesSeries
From http//www.hybridcenter.org
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Types of plug in hybrid vehiclesSeries-Parallel
From http//www.hybridcenter.org