Biodiesel 101 & Technical Overview National Biodiesel Board Technician Outreach Program June 2008
Driving Forces—Why Biodiesel?
Production Process and ASTM Spec
Demand and Availability
Biodiesel Driving Forces
Reduce dependence on imported crude oil and petrodiesel from unstable parts of the world
Reduce global warming by using a renewable fuel
Reduce harmful emissions from diesel engines
Can be used in any diesel engine without modifications, existing fueling stations can be used
Easy to use--drop in substitute for petroleum diesel fuel
Produces over 3 times more energy than it takes to grow and process the fuel
Engine and vehicle companies approve the fuel for use
Over 100 million miles of on-road trouble-free use both here and abroad
Why make biodiesel? Diesel fuel injectors are not designed for viscous fuels like vegetable oil Glycerin (thick) Biodiesel
Biodiesel , n. -- a fuel comprised of mono-alkyl esters of long chain fatty acids derived from vegetable oils or animal fats, meeting ASTM D 6751, designated B100.
Biodiesel Blend , n. -- a blend of biodiesel fuel with petroleum-based diesel fuel designated BXX, where XX is the volume percent of biodiesel.
This tight definition was needed in order to secure vehicle, engine and fuel injection equipment company support for biodiesel, as well as to secure ASTM specs
Biodiesel (B100) Definition
Raw Vegetable Oils and Fats
Partially Esterified Oils
Blends With Diesel
Non Ester Renewable Diesel
Adequate engine testing has not been thoroughly performed in some of these fuels
Biodiesel Raw Materials
Oil or Fat Alcohol
Sunflower Sodium hydroxide
Beef tallow Potassium hydroxide
Used cooking oils
Transesterification (the biodiesel reaction) Fatty Acid Chain Glycerol Methanol (or Ethanol) One triglyceride molecule is converted into three mono alkyl ester (biodiesel) molecules Biodiesel Triglyceride
Vegetable Oil or
Biodiesel (100 lbs.) + Glycerin (10 lbs.) In the presence of a catalyst Combining Yields
Important Biodiesel Parameters
Complete Reaction/Removal of Glycerin
Insured through total/free glycerin spec
Removal of Catalyst
Insured through sulfated ash spec
Removal of Alcohol
Insured through flash point spec
Absence of Free Fatty Acids
Insured through acid value spec
All these insured through ASTM D 6751
Specification for Biodiesel (B100) – ASTM D6751-07b (Dec. 2007)
ASTM Current Status
ASTM D 6751 is the approved standard for B100 to be used for blending in the U.S.
If B100 meets D 6751 and petrodiesel meets D 975, the two can be blended up to 20%
Similar to how #1 and #2 diesel are managed
The MOST important factor is B100 meeting ASTM D 6751 prior to blending
ASTM Current Status
ASTM is in the process of formally approving specifications for finished blends of biodiesel
For these blends, all biodiesel used must meet D 6751 prior to blending
Allowance of up to 5% biodiesel into ASTM D 975, the specification for petrodiesel, has been approved at the ASTM subcommittee level. Final vote expected in June 2008
A new ASTM spec for B6-B20 blends has been approved at the ASTM subcommittee level, with final vote expected in June 2008
Quality, Quality, Quality
B100 must meet D 6751 prior to blending to insure trouble-free use of B20 and lower blends
BQ-9000 fuel quality program helps to promote high quality fuel from producers and marketers
B20 and lower blends are recommended since most of the research and successful use of the fuel has been with these blends
See NBB Toolkit document “Use of Biodiesel Blends Up to B20” for more information
Blends over B20 require special precautions and should only be used by knowledgeable and experienced users
See NBB document “Guidance on Biodiesel Blends Above B20” for more information: http://www.biodiesel.org/pdf_files/fuelfactsheets/Use_of_Biodiesel_Blends_above_%2020.pdf
Biodiesel Industry’s “Good Housekeeping” TM seal of approval for biodiesel production & distribution companies
Quality Control System covers biodiesel manufacturing, sampling, testing, blending, storage, shipping, distribution
ASTM Grade Fuel, BQ-9000 Companies
Biodiesel (B100) Attributes
High Cetane (avg. over 50)
Ultra Low Sulfur (avg. ~ 2 ppm)
High Lubricity, even in blends as low as 1-2%
High Energy Balance (3.5 to 1)
Renewable, Sustainable, Domestically Produced
Increases overall fuel production capacity in USA
Reduces HC, PM, CO in existing diesel engines
B2 has up to 66% more lubricity than #2 Diesel
EPA required sulfur reduction in 2006
No overdosing concerns vs. other lubricity additives
Biodiesel and Global Warming
Closed Carbon Cycle: CO 2 Used to Grow Feedstock is Put Back Into Air
78% Life Cycle Decrease In CO 2
Energy Balance 3.5 to 1
Compression Ignition Platform (i.e. diesel) 30% More Efficient Than Spark Ignition (i.e. gasoline, CNG, propane)
Economic Development: Biodiesel
Creates Manufacturing Jobs
Creates Expanded Markets for Agricultural Products
Improves Balance of Trade
Increases Domestic Fuel Production Capacity
Putting renewable feeds through existing refineries doesn’t do this
Reduces Energy Imports and Dependence on Foreign Oil Sources
Good Fit as ‘Distributed Energy’ for Energy Security
2002 EPA HD Emissions Averages FTP Engine Dyno Summary - Higher % reductions occur at the lower blends - EPA is re-evaluating NOx data +2% -12% -12% -20% B20 +.2% -1.3% -1.3% -2.2% B2 +10% Oxides of Nitrogen (NO X ) -47% Particulate Matter -48% Carbon Monoxide -67% Total Unburned Hydrocarbons B100 Emission Type
Cold Weather Performance
Pure biodiesel does freeze faster than most petrodiesel
Your B20 supplier should provide blends of B20 that will not cause any cold flow issues in the winter
Exactly the same way they do with #2 diesel fuel
There are a variety of tools at the disposal of distributors to improve the cold flow operability of #2 petrodiesel and biodiesel blends
Blending with #1, cold flow additives, etc.
B20 has been used successfully in climates below -20 º F
Biodiesel Fuel Stability
The biodiesel specification contains parameters for insuring adequate fuel stability for normal applications
The shelf life of biodiesel blends is recommended by NBB as 6 months
Fuel Filters and Solvency
B20 & Under
Monitor filters, less than 2% need to be changed
Mild cleaning effect
Storage tanks may need to be cleaned, or keep extra filters on hand at start up
Housekeeping protocols for generic diesel equally important prior to blending
When switching old fuel tanks or vehicles to biodiesel, there may be some loosening of deposits.
Fuel tanks should be cleaned. If not possible, use finer filters.
Plan to change fuel filters once or twice after fuel changes.
Biodiesel is an excellent paint remover – don’t be sloppy when refueling.
Biodiesel will dissolve concrete – stop drips.
OEM Warranty Statements and Biodiesel
All major U.S. OEMs support B5 and lower blends, provided they are made with biodiesel meeting ASTM D 6751, the existing ASTM International standard for pure biodiesel (B100)
Many are progressing toward support for B20 pending approval of a new ASTM standard for B20 blends
Use of blends higher than B5 will not necessarily void existing warranties
For a complete listing of OEM position statements on biodiesel , visit:
Major OEMs’ Biodiesel Positions Accepts up to B20 in ISX, ISM, ISL, ISC and ISB engines; require BQ-9000 supplier Accepts up to B5 Cummins Detroit Diesel Case IH accepts up to B20 for most equipment; nearly half of all Case IH equipment also approved for B100. New Holland approves B100 in all equipment with New Holland diesel engines. Case IH New Holland Accepts up to B5 in most vehicles; B5 factory fill in Jeep Grand Cherokee and Dodge Ram; B20 approved for fleet use in Dodge Ram Chrysler Tiered acceptance for B30 / B20 / B5 depending upon equipment type and model Caterpillar
Major OEMs’ Biodiesel Positions Accepts up to B20; Recommends B5; Utilizes B2 factory fill for all U.S. diesels John Deere Accepts up to B5 produced from Soy (SME) Mack Accepts up to B5 Isuzu Accepts up to B5; working toward B20 VW Accepts up to B5 Volvo Truck Accepts up to B5 Mercedes Accepts up to B5 International Accepts up to B5; B20 offered as Special Equipment Option for fleets on select vehicles General Motors Accepts up to B5; working toward B20 Ford
Disadvantages of biodiesel
Lower Energy Content
8% fewer BTU’s per gallon, but also higher cetane #, lubricity, etc.
Poor cold weather performance
This can be mitigated by blending with diesel fuel or with additives, or using low gel point feedstocks such as rapeseed/canola.
Biodiesel is less oxidatively stable than petroleum diesel fuel. Old fuel can become acidic and form sediments and varnish. Additives can prevent this.
Fuel Energy Content
Biodiesel has less energy content (lower heating value) than diesel fuel.
No. 2 diesel fuel 18,300 129,050
Biodiesel 16,000 118,170
(12.5% less) (8% less)
Diesel fuel is injected volumetrically, so energy per unit volume is important.
Biodiesel will cause 8% power loss.
Dense fuels provide more energy per gallon.
No. 1 diesel fuel = 0.81
No. 2 diesel fuel = 0.84 -0.855
Biodiesel = 0.878-0.88
Low energy content
Not harmful, but may cause power loss and increased fuel consumption
Cold flow – fuel filter plugging
Microbial growth – fuel filter plugging
Incomplete reaction – fuel filter plugging
Fuel oxidation – fuel filter plugging
Fuel filter plugging is the most common operational issue
Engine Wear Issues
Biodiesel only contacts the fuel system so use should not affect bearings, turbo, oil/water pumps, and other wear-related parts.
Biodiesel improves fuel lubricity and thus can be used as a lubricity additive for poor quality diesel fuels.
In Europe, there have been some claims of crankcase oil dilution and oil thickening. This has not been observed in the U.S.
Handling and Storage
Some older fuel lines (Buna, natural rubbers) are not compatible with biodiesel and will degrade.
Viton and Teflon hoses and seals are widely used today and are compatible with biodiesel.
No copper, brass, bronze, zinc, or other galvanized surfaces