BIODIESEL: Understanding It's Potential and Limitations

Jim Glancey
Departments of Bioresources Engineering
and Mechanical Engineering
University of Delaware
Newark, DE 19716

Discussion Items
  • The Basics of Biodiesel
  • Production, Distribution and Blending
  • Performance as an Engine Fuel
  • Warranties
  • Heating Oil
  • Handling and Storage to Maintain Fuel Quality
Biodiesel - Driving Forces
  • Excess supply of fats and oils
  • Potential for better emission
  • Reduce dependence on petroleum
  • Increase lubricity of the fuel to compensate for lower Sulfur content
  • Safety and handling – less volatile fuel
  • Incentive Programs
What is Biodiesel?
  • A compression ignited fuel made
  • from a renewable resource
  • Chemically
    • Long chain fatty acid mono alkyl esters
    • Exact chemical composition different for different sources of oil.
    • Combustion
      • Biodiesel Air/Fuel Ratio = 13.5
      • Petro-Diesel Air/Fuel Ratio = 15
  • Its a good solvent
The Biodiesel Reaction

Biodiesel Sources
  • Vegetable Oil
    • Soy
    • Canola/Rapeseed
    • Corn
    • Cotton
    • Used cooking byproducts
  • Animal
    • Beef tallow
    • Pork lard
    • Used cooking byproducts
Important Processing Considerations
  • Complete reaction = no un-reacted oil
  • Removal of Glycerin
  • Removal of Catalyst
  • Removal of Alcohol
  • Absence of free fatty acids
Insured through ASTM D6751

Classifications
  • Biodiesel always refers to 100% biofuel.
  • Biodiesel Blends refers to a fuel that is
  • composed of a mix of Biodiesel and
  • Petroleum-Based Diesel
  • Blend Designations
    • BXX – XX is the % Biodiesel
    • Examples:
      • B20 – 20% Biodiesel, 80% Petro-Diesel
      • B100 – 100% Biodiesel (Neat)
Worldwide Fuel Charter
-ASTM 6751
-B5 Recommendation

Blending
  • Biodiesel that meets ASTM 6751 is blended with Petroleum Diesel Fuel.
    • Some common blends: B2, B5, B20
  • Biodiesel is heavier than Petroleum Diesel
  • Splash Blending (Tank Mixing)
    • Always add biodiesel on top of petroleum diesel
    • Cheap and effective for mixing
Rack or In-Line Blending
Simple Rack Blender
Blending with Additives
Blending in Delaware/Maryland
  • Distributors with up to 3 years experience
  • Buying B100 from Iowa and Ohio
  • Blend B100 with petro-diesel.
  • Underground Tanks for B100 are temperature controlled
  • Sell everything from B2 to B100
  • Cold flow improver in bulk B100
    • -40 F pour point in B20
    • 30 F in B100
Biodiesel Blend Quality
  • Unlike gas engines, diesel engines will run on poor fuel.
  • Currently, no good test or standard exists for blended biodiesel.
  • Once blended, it is difficult to determine if good quality biodiesel was used.
  • So . . . you need to interrogate and rely on your supplier to confirm quality
Biodiesel Performance
  • Power and Efficiency
  • Emissions
  • Low Temperature
  • Material Compatibility
  • Cost

Taken at the diesel truck drag races on Rt. 13
just outside Greenwood, DE
Performance – Energy Value


Power and Efficiency Compared to Petroleum Diesel
  • B100 – 10% less energy per gallon
  • B20 – about 2% less energy per gallon
  • Road studies of fuel efficiency reductions
    • B100: 4.1 to 10.1 MPG
    • B20: 0.9 to 2.1 MPG
Emissions from Biodiesel Blends Compared to Petroleum Diesel

Cloud Point for a Biodiesel and Biodiesel Blends – no additives
  • B100 25 to 30 F
  • B20
    • Soybean-base -14 F
    • Canola/Rapeseed-base -15 F
    • Lard-base -3 F
    • Eatable Tallow -2 F
    • Fatty Acid Grease -6 F
 Cloud Point - Temperature at which wax crystals start to form.

Cold Filter Plug Point

Material Compatibility
  • Soft Metal
    • Copper, brass, zinc, lead and tin parts should be replaced with aluminum or steel since these metals oxidize both diesel and Biodiesel fuels.
  • Seals
    • Teflon and Viton are must use sealing devices, not Buna, Nitrile, Polyurethane. Polypropylene and Polyvinyl are not acceptable sealing devices.
Biodiesel Costs
  • B100 – about $3.00/gal at the pump
    • $2.00/gal for the fuel
    • $0.50/gal rail charge from Iowa
    • $0.50/gal road tax
  • B20 - $1.76/gal at the pump
  • Rule of thumb – an extra penny per gallon for each percentage point of biodiesel
Warranty Issues
  • Cummins and Caterpillar
    • “neither approves or disproves the use of biodiesel fuel and blends”
    • Problems causes by the fuel will not be covered.
  • Caterpillar
    • B5 blend maximum for 3003 through 3034, 3054, 3056 engine models
    • Other models - blended
  • John Deere
    • Most recent policy statement regarding Biodiesel blends was February, 2002.
    • Approved up to 5% soy-based blend in all Power Tech engines.
    • “We do not endorse using higher percentage blends at this time”
    • Why?
      • Possible fuel quality issues
      • Deere R&D is consumed with developing a new engine to meet the Tier 3 emission requirements required in 2006.
  • Volkswagen
    • Some claims that VW voids warranties if biodiesel blends are used.
    • Currently, European VW engines are warranted for B20 and B100.
    • VW had invested in “Sunfuel” - biodiesel from biomass.
    • Volkswagen AG and Archer Daniels Midland
    • Announce Biodiesel Research Agreement
    • Announced Monday January 5
Biodiesel Blends as Heating Fuel
  • B2 and B5 have been used
  • Emissions including NOx goes down
  • Given the change in fuel chemistry,
  • adjustment of the air/fuel ratio may be required.
  • Soft metal fuel lines (copper) and natural rubber present problems
Maintaining Fuel Quality
  • Purchase only quality fuel and keep it clean
  • Start with clean storage
  • Minimize Contaminants
    • Air
    • Water
    • Fuel
    • Microbes
  • Don’t store biodiesel for more than 6 months
  • Regular housekeeping
  • Problems usually occur early
Fuel Additives
  • Four Types for Diesel
    • Engine Performance
    • Fuel Stability
    • Fuel Handling
    • Contamination Control
Biodiesel Incentive Programs
  • Delaware Soybean Board
    • Paying for a soybean grower’s first purchase of Biodiesel
    • Planning to offer totes
  • MD Soybean Board
    • Refunds half the cost up to $1000
    • Giving away $275 totes
Summary
  • Extensive research exists on biodiesel formulations and performance.
  • One of the biggest challenges for the industry is insuring consistent quality at a competitive price.
  • Important issues for end users:
    • Know and trust your source of fuel
    • Make sure fuel meets fuel standards
    • When in doubt, verify warranty policy
    • Check regularly for seal degradation with older engines
  • End users responsible for maintaining fuel quality.


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