1. Effect of Biodiesel Components on Cetane Number and Lubricity
Kapila Wadumesthrige
NBEL
Department of Chemical Engineering
Wayne State University

2. Biodiesel Composition
Methyl esters of long chain fatty acids
> 98 % FAME
< 2% of other components
Free Glycerin
Mono, di and tri glyceride
Antioxidants
Sterols
Phospholipids
Water

3. Biodiesel properties High calorific value – FAME
Oxidation stability- unsaturation/ antioxidants
Cold flow properties- chain length/ saturation /sterols ?
Ignition quality – oxygenated/ minor components
Lubricity – FAME/ FFA/other?

4. Effect of composition on biodiesel Ignition Quality
DCN = 83.99(ID-1.512)
measure of the ignition quality of diesel fuel via the compression ignition process.
is actually a measure of a fuel's ignition delay
Ignition Delay-the time period between the start of injection and start of combustion
Diesel fuels with required Cetane number improve
cold starting, reduce smoke during start up
improve fuel economy, reduce exhaust emissions,
reduce noise and vibration, improve engine durability
From a number of fuel injection/combustion events, an average ignition delay (ID) can be determined. This average ID is then used in a correlation equation to determine a derived cetane number
ASTM test D using IQT

5. Derived Cetane Number (DCN) of biodiesel
EN standard
US standard
Biodiesel samples stored under ambient conditions

6. DCN of biodiesel at various conditions
Distilled biodiesel contains only FAME
DCN variation of distilled BD due to FAME composition

7. Oxidation of Distilled Cotton Seed BD Vs. Cetane number
Oxidation at 110 C, 10 L/min Air
FAME composition (%) of oxidized cotton seed biodiesel

8. Cetane number of BD depends on chemical composition of FAME,
amount of trace compounds
secondary products due to oxidation of FAMEs.

9. Effect of major and minor components of biodiesel on petroleum and synthetic fuel
Quality that prevents wear when two moving metal parts come in contact with each other.
Desulphurization reduces the inherent lubricity of diesel
Adding bio diesel at low levels (1-2%) increase the lubricity of low sulfur diesel.

10. Lubricity increases sharply as BD blending level increase then levels off at ~2% limit.

11. Lubricity of Refined Soy Biodiesel
Acid numbers; Soy BD = 0.25, Refined Soy BD = 0.19
Palmatic acid equal to 0.06 Acid # added to refined Soy BD

12. Lubricity increases sharply as BD blending level increase then levels off at ~2% limit.
BD lubricity is due to combination of major and minor components