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Washington State DOT Biodiesel Workshop
Dr. Andrew McKnight Innospec Fuel Specialties
March 22, 2012
It Was a Warm Cold Winter!
* source: National Climatic Center/NESDIS/NOAA
vs. monthly average for 1981-2010 base period vs. monthly average for 1971-2000 base period
Temperature Anomalies -- January 2012*
Topics
! “The Challenge of ULSD” ! Diesel Fuel Chemistry ! Effect of Fuel Composition on Low Temperature
Operability ! Cold Flow Improvers – How do they work? ! The Challenge of Biodiesel ! Washington State Winter 2011-12 Cold Flow
Performance
The Challenge of ULSD
ULTRA LOW SULFUR DIESEL
Polar Compounds
Aromatics / Olefins Saturated Hydrocarbons
Natural Biocides
Natural Stabilizers
Fuel Density
Caustic Carryover
Water Fallout LOW SULFUR DIESEL
The Challenge of ULSD What happened to the fuel during the conversion?
ULTRA LOW SULFUR DIESEL
Polar Compounds
Aromatics / Olefins Saturated Hydrocarbons
Natural Biocides
Natural Stabilizers
Fuel Density
Caustic Carryover
Water Fallout
Low
Tem
p O
pera
bilit
y
Cor
rosi
on
Mic
robi
al G
row
th
Con
duct
ivity
In-V
ehic
le S
tabi
lity
Lubr
icity
LOW SULFUR DIESEL
The Challenge of ULSD What happened to the fuel during the conversion?
ULTRA LOW SULFUR DIESEL
Polar Compounds
Aromatics / Olefins Saturated Hydrocarbons
Natural Biocides
Natural Stabilizers
Fuel Density
Caustic Carryover
Water Fallout
Low
Tem
p O
pera
bilit
y
Cor
rosi
on
Mic
robi
al G
row
th
Con
duct
ivity
In-V
ehic
le S
tabi
lity
Lubr
icity
LOW SULFUR DIESEL
CFI
The Challenge of ULSD What happened to the fuel during the conversion?
Diesel Fuel Chemistry
Diesel Fuel... ... Is a Mix of Several Types of Hydrocarbons
Selected Hydrocarbon Types
Paraffins Naphthenes Aromatics Olefins
n-Decane
iso-Decane
Butylcyclohexane
Decalin Naphthalene
Butylbenzene Heptene
Diesel Fuel Straight Chain Paraffins (Wax)
5 Carbons = C5
12 Carbons = C12
16 Carbons = C16
18 Carbons= C18
Diesel Fuel What Do We See When Paraffins Crystallize?
Heavy, large crystals
sediment and agglomerate at
the bottom of the tank where fuel
is drawn
Large paraffin crystals
can block filter pores
Wax can build up in sharp bends restricting flow
Diesel Fuel Where Does Crystallization Affect Vehicle Operation?
Diesel Fuel General Low Temperature Operability Terms
Cloud Point Untreated
CFPP Untreated
PP Untreated
Diesel Fuel What’s Really Happening When Paraffins Crystallize?
Super saturation / Nucleation
Cloud Point Visible Crystals
Existing Crystal Grow Additional Nucleation Occurs
Larger crystals begin to adhere along the
edges trapping liquid in “pockets”.
TEMPERATURE
Crystal growth
No Flow Point Pour Point
Fuel solid / gelled
13oF
10oF
7oF
0oF
CFPP ? > 0.4% wax
Morphology Phenomenon Observation
No Visible Crystals
Cold Flow Improvers What Affects Their Response?
Fuel Composition How Does it Affect Wax Crystallization?
! Solvency of the Fuel – Primary driver is “aromaticity” – Higher aromaticity ~ more wax can
be dissolved at a given temperature
Aromatics
Naphthalene
Butylbenzene
Fuel Composition How Does it Affect Wax Crystal Growth?
! Solvency of the Fuel – How much wax can be dissolved at a given temperature
! Total Wax – How much precipitates between the cloud point and a given
temperature is a critical factor in Low Temperature Operability (LTO)
– Higher wax content à more wax near the cloud point
0
2
4
6
8
10
12
14
16
18
20
0 25 50 100 150 200 250 300 350 400 450 500
Active Additive PPM
CFPP
(oC)
0.8%1.0%1.2%1.4%1.6%1.8%2.0%
75 ppm
110 ppm
+47% +16%
170 ppm
+126% +33%
275 ppm
+266%
+50%
Fuel Composition Total Wax Content
Fuel Composition How Does it Affect Wax Crystal Growth?
! Solvency of the Fuel – How much wax can be dissolved at a given temperature
! Total Wax – How much precipitates between the cloud point and a given
temperature is a critical factor in Low Temperature Operability (LTO)
– Higher wax content à more wax near the cloud point
! Wax Distribution – The amount of each wax chain length relative to the other
waxes has a dramatic impact on wax crystal formation, operability at low temperature and ability to treat with CFI
Broad Wax Distribution
Increasing boiling point = increasing wax length
0
5
10
15
20
Normal 1.1 2 3.5 5.7 8.7 12.1 14.8 15.9 17.2 15.6 13 9.9 7.4 5.1 2.9 1.4 0.9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
Narrow Wax Distribution
0
5
10
15
20
Normal 1.1 2 3.5 4.4 5.7 7.1 9 15.9 17.2 15.6 13 6.5 4.6 4.1 2.8 1.4 0.9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
Heavy End Wax Distribution
0
5
10
15
20
Normal 1.1 2 3.5 5.7 8.7 12 15 16 16 16 13 9.9 7.4 5.1 2.9 2.5 1.8 1.5 1.3 1.1 0.8
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 26 27 28 29
! Solvency of Fuel ! Total Wax
– More wax requires more CFI
! Wax Distribution – No single CFI additive responds well in all diesel fuels. – Additive structure and chemistry needs to be “tailored” to the
paraffin composition of the fuel to be treated
Fuel Composition Key Points
Cold Flow Improvers
How do they work?
Cold Flow Improver (CFI) Function
Cloud Point Untreated
CFPP Untreated
PP Untreated
Cloud Point with CFI
CFPP with CFI
PP with CFI
Allows operations lower than that of untreated fuels
improver
Polymer attaches to growing wax crystal surface and inhibits further wax deposition
Crystal Growth Modification ”Growth Arrest”
Form and size of n-paraffin crystals are influenced by adding CFI‘s
CFI
Crystallisation depends on type and amount of waxes as well as on the middle distillate oil matrix, e.g. aromatics, naphthenics
Crystal Growth Modification ”Growth Arrest”
– Additive precipitates from fuel before n-paraffins – Provides growth / nucleation site for precipitating wax molecules
Crystal Growth Modification ”Nucleation”
Nucleation and Filter blocking
Treated with Treated with MDFI Typical Anti-Gel/PPD
-80
-70
-60
-50
-40
-30
-20
-10
0
10
20
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Tem
pera
ture
(°F)
Percent #1 ULSD
Cold Flow Data for B5 Blends with #1 ULSD (ULSD source - Montana)
Cloud Point
CFPP
Effect of Kerosene on B5 CFPP
-80
-70
-60
-50
-40
-30
-20
-10
0
10
20
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Tem
pera
ture
(deg
F)
Percent #1 ULSD
Cold Flow Data for B5 Blends with #1 ULSD (ULSD source - Montana)
Cloud Point
CFPP
CFPP with Cold Flow Improver
Effect of Kerosene vs Cold Flow Improver on B5 CFPP CFI much more effective
The Challenge of Biodiesel
Biodiesel Saturated Fat Content vs Cold Flow
0
10
20
30
40
50
60
70
80
90
100
Soy Corn Cotton Sunflower Lard Tallow Inedible Grease
Canola Coconut
% F
at
% unsaturated % saturated
Remember Narrow Wax Distributions?
0
5
10
15
20
Normal 1.1 2 3.5 4.4 5.7 7.1 9 15.9 17.2 15.6 13 6.5 4.6 4.1 2.8 1.4 0.9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
Adding B100 Enriches Diesel in 16 and 18 Carbon Molecules
Melting Point of C18 Fatty Acids
Stearic Acid MP = 157 °F
Oleic Acid MP = 55 °F
Linoleic Acid MP = 10-23 °F
-25
-20
-15
-10
-5
0
5
10
ULSD B5 Soy B10 Soy B5 Tallow B10 Tallow
CFP
P (d
eg F
)
untreated
1000ppm
Soy and Tallow B100 in “easy to treat” N.E. U.S. ULSD Tallow most problematic, at 10%
-8
-6
-4
-2
0
2
4
6
8
10
ULSD B5 Soy B10 Soy B5 Tallow B10 Tallow
CFP
P (d
eg F
)
untreated
1000ppm
2000ppm
Soy and Tallow B100 in “hard to treat” N.E. U.S. ULSD
Low Temperature Operability of BX Blends
Cloud Point LTFT Untreated
CFPP Untreated
LTFT with CFI
Cloud Point LTFT Untreated
CFPP Untreated
LTFT with CFI
CFPP with CFI
LTFT Untreated
CFPP with CFI
-28
-26
-24
-22
-20
-18
-16
-14
-12 ULSD SME B2 CME B2 CME B5
Tem
pera
ture
oC
Cloud Point LTFT Untreated LTFT PL-2315.3 1175 mg/L Target CFPP Cloud Point LTFT Untreated CFPP Untreated
ULSD B5 SME B11 SME B20 SME
Illinois Winter Fuel
Washington State Winter 2011-12 Cold Flow Performance
-60
-50
-40
-30
-20
-10
0
10
20
-20 -15 -10 -5 0 5 10 15 20
CFP
P (°
F)
Cloud Point (deg F)
WA State Winter 2011-2012 Field Data UNTREATED Fuels
Untreated Diesel from WA State
-60
-50
-40
-30
-20
-10
0
10
20
-20 -15 -10 -5 0 5 10 15 20
CFP
P (°
F)
Cloud Point (deg F)
WA State Winter 2011-2012 Field Data UNTREATED Fuels
Roughly linear (CP = CFPP)
Untreated Diesel from WA State
-60
-50
-40
-30
-20
-10
0
10
20
-20 -15 -10 -5 0 5 10 15 20
CFP
P (°
F)
Cloud Point (deg F)
WA State Winter 2011-2012 Field Data
Treated Diesel from WA State
Untreated fuels
-60
-50
-40
-30
-20
-10
0
10
20
-20 -15 -10 -5 0 5 10 15 20
CFP
P (°
F)
Cloud Point (deg F)
WA State Winter 2011-2012 Field Data
Treated Diesel from WA State
Untreated fuels
Cold Flow Improver depresses CFPP ~ 25°F