NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy ,operated by the Alliance for Sustainable Energy, LLC.

Teresa L. Alleman, Robert L. McCormick

National Biodiesel Conference

San Francisco, CA

2 February 2009

NREL/PR-540-45184

2008 B20 Survey Results
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Acknowledgments

• Department of Energy 

• National Biodiesel Board

• Engine Manufacturers Association
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2004 B20 Quality Survey Results

• 22 producers in the marketplace (25 M gallons)

• Samples obtained nationwide from biodiesel blenders 

(27 samples)
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Biodiesel Content from 2004 Survey

•18 samples (36%) fall outside 

the 18-22% range

•Likely cause: poor mixing 

during splash blending

Sample ID

0 5 10 15 20 25 30 35 40 45 50 55

Biodiesel Content, FTIR method

0

20

40

60

80

100
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B20 Survey and D7467

• This B20 survey was taken as part of a cooperative effort 

between NREL, the National Biodiesel Board (NBB), and the 

Engine Manufacturers Association (EMA) to gain further 

information on B20 in the market (Biodiesel Blend Evaluation 

Team, BBET).

• ASTM D7467 (ASTM spec for B6 to B20 blends) was not released 

for use until October 2008.

• B20 samples were taken prior to release of D7467.

• Parameters, in addition to those proposed in D7467, were 

analyzed for additional information to provide data to ongoing 

NREL, NBB, and EMA technical efforts on biodiesel.

• D7467 was designed so B6 to B20 would always be in-spec if inspec diesel and in-spec biodiesel were used to meet the blend.

• Recent B100 survey indicated 90% of biodiesel volume meets 

D6751.
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Pump Labeling

• There were no pump labeling regulations in effect when the 

samples were taken.

• Only pumps that were labeled ‘B20’ were sampled.

• Only fleets that identified that they were purchasing and using 

B20 were sampled.

• As part of EISA 2007, the Federal Trade Commission (FTC) 

issued federal regulations requiring pump labels for biodiesel 

pumps, which took effect in Dec. 2008:

– Less than 5% biodiesel content does not require a label.

– Pumps with biodiesel content between 6% and 20% must be 

labeled with wording such as ‘contains between B6 and B20.’

– Pumps over B20 must be labeled with the exact percentage of 

biodiesel.

• NCWM is adopting the FTC pump labeling language for 

biodiesel blends as part of NIST Handbook 130.
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2008 B6-B20 Property Testing

Property Test Method S15 Limits

Acid number, mgKOH/g D664 0.3 max

Viscosity at 40°C D445 1.9-4.1

Flash point, °C D93 52

Cloud point, °C or LTFT/CFPP, °C D2500 or 

D4539/D6371 Report

Sulfur, ppm D5453 15 max

T90, °C D86 343 max

Carbon residue, mass% D524 0.25 max

Cetane number D613 40 min

Cetane index D976 40 min

Aromatics, vol% D1319 35 max

Ash, mass% D482 0.01 max

Water and sediment, vol% D2709 0.05 max

Copper corrosion, 3 hours at 

50°C D130 No. 3 max

Biodiesel content, vol% D7371 6-20

Oxidation stability, hrs EN14112 6 min

Lubricity, μm D6079 520 max

Property Test Method

Acid number, mgKOH/g D664

Flash point, °C D93

Cloud point D2500

Sulfur, ppm D5453

Group I and II metals, ppm D7111

Karl Fisher, ppm D6304

Cetane number D6890

Particulate contamination, ppm D6217 or D7321

Interfacial tension, mN/m D971

Ash, mass% D482

Free glycerin, mass% In-house method

Total glycerin, mass% In-house method

Biodiesel content, vol% D7371

Oxidation stability, hrs EN14112

D7467 Specification Tests Performed
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Sample Collection

•32 samples collected 

across the United 

States in late spring 

and early summer

•Sample locations 

chosen to cover widest 

geographic range 

possible

•Collected from fleets 

using B20 or from 

public pumps

– Only selected pumps 

stating product was 

B20
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Results

(Note: D7467 was not in effect when 

samples were collected.)
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Blend Percentage Results

•60% of samples were 

nominally B20

•Sample distribution 

much different than 

for 2004 results

– All fleet samples 

were nominally B20

•Much fewer samples 

above B20 

•Most off-spec samples 

were less than B20

– Typically B11, B5, 

and B2

Sample ID

0 5 10 15 20 25 30 35

Biodiesel Content, D7371, %

0

20

40

60

80

100

Nominally B20

Less than B20

Greater than B20

Fleet Samples
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Induction Period Stability

•D7467 not required when samples were collected

•74% within D7467 for B20 Induction Period

Sample ID

0 5 10 15 20 25 30 35

Induction Period,

EN14112, hrs

0

5

10

15

20

25

Nominally B20

Less than B20

Greater than B20

Specification is 6 hrs, min

Testing was stopped

after 12 hours

Average B20 Induction Period = 8.4 hrs

Fleet Samples
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Acid Value Results

•97% within D7467 for B20

Sample ID

0 5 10 15 20 25 30 35

Acid Value, D664, mgKOH/g

0.0

0.1

0.2

0.3

0.4

Nominally B20

Less than B20

Greater than B20 Specification Limit = 0.3, max

Fleet Samples

Samples at 0.05 mgKOH/g are 

below detection limit
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ASTM SC06 Modifications to D664

•Modifications are being balloted at ASTM

•Allows better discrimination at lower acid values

Acid Value, D664, mgKOH/g

0.0 0.1 0.2 0.3 0.4 0.5

ASTM SC06 proposed

modifications to D664, mgKOH/g

0.0

0.1

0.2

0.3

0.4

0.5

Note samples that are below detection

limit on D664 have been assigned a 

value at that limit of 0.05

The samples were analyzed using the

current method upon collection. There

was a delay of several weeks before

they were analyzed using the 

modified method.
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Cloud Point

Sample ID

0 5 10 15 20 25 30 35

Cloud Point,

D2500 

o

C

-26

-24

-22

-20

-18

-16

-14

-12

-10

-8

-6

Nominally B20

Less than B20

Greater than B20

Average B20 CP = -12.6oC Fleet Samples
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Flash Point

Sample ID

0 5 10 15 20 25 30 35

Flash Point, D93, 

o

C

35

40

45

50

55

60

65

70

75 Nominally B20

Less than B20

Greater than B20

52oC minimum flash point if

CP is >-12o

C

38o

C flash point if

CP is <-12o

C
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Other D7467 Properties

Property ASTM Method Range, Average

Sulfur, ppm D5453 3.7-16.2, 7.3

Derived cetane number D6890 45-56, 49

Ash, mass% D482 BDL, BDL

* BDL: below detection limit
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Results − Non-D7467 Properties
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Karl Fisher Moisture

• Current biodiesel and diesel specifications measure ‘free water’ using 

a centrifuge method for ‘water and sediment.’

– D6751, D7467, D975

– Free water is the property of most concern as this can increase waterrelated issues.

• EMA members desired information on both the free water and the 

entrained/soluble water.

• Karl Fisher moisture measures both the free water AND any 

entrained/soluble water (not part of the current specifications for 

biodiesel, biodiesel blends, or petrodiesel).

• B100 can hold slightly more water in solution than most petrodiesel.

• There is an ongoing working group within the ASTM Biodiesel Task 

Force looking into replacing the current water and sediment test 

method with a separate measure for KF moisture and a separate 

measure for fuel particulates.
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Karl Fisher Moisture

Sample ID

0 5 10 15 20 25 30 35

Karl Fisher Water, D6304, ppm

0

50

100

150

200

250

300

350

Nominally B20

Less than B20

More than B20 B20 average KF water = 130 ppm

Fleet Samples
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Interfacial Tension

Sample ID

0 5 10 15 20 25 30 35

Interfacial Tension, D971, mN/m

0

5

10

15

20

25

Nominally B20

Less than B20

Greater than B20

Average B20 IFT = 12.3 mN/m

Fleet Samples
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Group I and II Metals

Property, 

ASTM D7111

Range, Average

Mg, ppb

K, ppb

<100 (detection limit for all samples)

Ca, ppb <100 to 652, 219

Na, ppb <500 to 2000*, 606

* 1 sample would be off-spec at B100 for Na.

• Group I and II metals are controlled at the B100 level:

– Sulfated ash of 0.02%

– 5 ppm maximum of combined Na/K

– 5 ppm maximum of combined Ca/Mg

• Method not approved for biodiesel used to measure these 

metals in the low concentrations expected in the blends 
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Conclusions − D7467 Properties

• B20 samples were collected from around the United States, from public 

pumps and fleets as part of joint effort of NREL, NBB, and Engine 

Manufacturers Association.

• D7467 was not enacted when these samples were taken.

• 60% of blends were nominally B20.

– Distribution of non-B20 samples was different from that in last survey, with 

much less fuel above 20%; indicates less splash blending type issues but still 

room for improvement.

– High percentage below B20 indicates need for improvement in pump label 

management and enforcement.

• Average cloud point (CP) = -12.6oC (9oF).

– No CP specification ; determined by geography, time of year, customer.

• Average flash point = 59oC (138oF); none outside D7467.

• 74% of samples met D7467 induction period stability requirements for 

B20.

• Only 1 sample off-spec for D7467 acid value.

– Indicates fuel had not degraded to the point of being problematic even 

though the induction period was below current D 7467 specification level.
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Conclusions − Non-D7467 Properties

• Interfacial tension average was 12.3 mN/m.

• Average Karl Fischer moisture was 130 ppm.

– ULSD can average 50-150 ppm.

• Elevated Na content was observed in 1 sample, indicating 

the B100 was not on-spec (blend was off-spec for other 

parameters as well). 

• Ca, Mg, and K were extremely low and near detection limits.
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Recommendations

• ASTM has issued the new D7467 specifications for B6 to 

B20 blends, and FTC has issued nationwide pump labeling 

requirements for biodiesel blends.

• Fuel enforcement agencies now have specifications to 

help enforce quality of biodiesel blends.

• Improvement is needed to ensure that the amount of 

biodiesel being advertised is what is really being provided 

to the customer (although this seems to have improved 

since the last survey).