what is this stuff on my filter, argentina 2009 (nx power lite)
DESCRIPTION
Some users of biodiesel experience fuel filter failure at temperatures well above the cloud point of the fuel. Much research has been done on oxidative stability of B100. Very little research has been done on Bxx blends of biodiesel and petroleum diesel. This paper examines why biodiesel must always be treated with anti-oxidant not matter what the Racimat Induction Period of the base B100 fuel.TRANSCRIPT
Phil Bureman
Nalco CompanyIndustry Technical Consultant – BioFuels
What Is This Stuff on my Fuel Filter?13th Latin American Congress on Fats & Oils
Rosario, Argentina, November 1, 2009
Tim McGinnis
Nalco CompanyResearch Scientist - Research Analytical
Kim Peyton
Nalco Energy ServicesResearch Scientist
2
Who Is Nalco?Who Is Nalco?
• Nalco is a global company with approximately $4 billion in annual sales
• Nalco has 2 Major Divisions• Nalco Water & Process Solutions
works with BioFuel producers including biodiesel
• Nalco Energy Services works with petroleum refiners and fuel
marketers
• There is regular information sharing between the two divisions
3
The Future of BiodieselThe Future of Biodiesel
• Biodiesel fuel quality continues to improve• Conversion technologies are becoming more
efficient• New feed stocks are available
Advanced feed stocks are being developed
• Governments are becoming supportive of biofuels Some more than others
• Cold weather issues are becoming better understood and managed
• We have one major obstacle between our industry and success:
4
The Future of BiodieselThe Future of Biodiesel
• Biodiesel producers must better understand petro diesel
• Petro diesel refiners must better understand biodiesel
• If the Biodiesel Producer and the Petroleum Refiner regularly communicate and work together to solve performance problems, then both will be profitable and the Biodiesel user will be a Satisfied Customer!
5
BackgroundBackground
• There has been much study of B100 oxidation stability Test methods such as Rancimat are well established,
repeatable, and quite useful.
• There has been some study of B100 oxidation stability: Under long term storage conditions Under stressful conditions of heat & humidity
Storage Condition @ 30 C in saturated humidity
Beef Tallow B100 with no oxidation inhibitor
Date WeekRancimat Induction Period
(Hours)% Reduction in
Oxidation Stability9/29/2008 0 3.45 -10/6/2008 1 1.1 68.1%10/20/2008 3 0.8 76.8%11/3/2008 5 0.6 82.6%11/17/2008 7 0.4 88.4%
6
BackgroundBackground
• There has been very little study of the oxidation stability of Bxx blends– Especially with the new petroleum based
Ultra Low Sulfur Diesel (ULSD) fuels
• Why is this important?
7
BackgroundBackground
• There is a significant amount of Bxx stored for long periods of time: Farms (typical 3 month storage) Home heating oil (1 year storage) Construction contractors (3 months) Back-up fuel power generators
o Hospitalso Electric power utilities (1-5 years)
• There have been credible reports of excessive fuel filter fouling in B5, B10 & B20 In some Bxx storage tanks At some “fuel blender” terminals
o During warm weathero No sediment was found on the B100 filter
The weather was warm
Nalco decided to investigateNalco decided to investigate
8
BackgroundBackground
• The filter foulant was not biological• The filter foulant was not:
Petroleum fuel varnish Rust or A known petroleum tank sludge or sediment
• The filter foulant did not contain unusual amounts of water, alkali metals, soap, glycerin or glycerides
• Since the problem occurred in Bxx and not B100, Nalco decided to investigate long term Bxx storage stability
9
BackgroundBackground
• ASTM D4625 was chosen as the fuel ageing method Long history of use to simulate 1 year of storage for
petroleum fuels Runs for 13 weeks at 110oF (43oC), with no agitation
• Three different types of B100 were chosen, Biodiesel made from Soy Oil (5.1 hour Rancimat as a B100) Mixed source (0.6 Hour Rancimat as a B100) Palm oil feedstock (4.8 Hour Rancimat as a B100) None of the B100’s had been treated with anti-oxidant Some of the B20 and B5 samples were treated with anti-
oxidants The ULSD had not been treated with stabilizer or lubricity aid
• ULSD (Ultra Low Sulfur Petro Diesel), B100, B20 and B5 blends were tested
AfterAfter ASTM D4625, 110 ASTM D4625, 110ooF F (43oC), 13 weeks , 13 weeks With No Antioxidant Treatment
There was no indication of significant sediment formationThere was no indication of significant sediment formationULSD Mixed
Soy Palm
Rancimat Hours Prior to ASTM D4625:>8.0 Hrs 0.6 Hrs 5.1 Hrs 4.8 Hrs
A thick,gelatinous sediment layer formed at the bottom of the B20 blend to which no antioxidant hasbeen added.
This sediment did not form in inhibited B-20.
UntreatedAnti-Ox #1 @ 100 ppm in the B100
Anti-Ox #2 @ 100 ppm in the B100
~ 10.5 vol%
A smaller amount of the same sediment formed in the B5A smaller amount of the same sediment formed in the B5
Non-Inhibited SOY B20 Non-Inhibited SOY B20 (Rancimat before testing >8.0 Hrs), (Rancimat before testing >8.0 Hrs),
in ULSD in ULSD without anti-oxidant treatment is unstable after accelerated stability testing
A thick,gelatinous sediment layer formed at the bottom of the B20 blend to which no antioxidant hasbeen added.
This sediment did not form in inhibited B-20.
UntreatedAnti-Ox #1 @ 100 ppm in the B100
Anti-Ox #2 @ 100 ppm in the B100
~ 7.0vol%
A smaller amount of the same sediment formed in the B5A smaller amount of the same sediment formed in the B5
Non-InhibitedNon-Inhibited Mixed Source B20 Mixed Source B20 (Rancimat @ start 3.7 Hrs), (Rancimat @ start 3.7 Hrs),
in ULSD showed similar instability when subjected to ASTM D4625
13
ObservationsObservations
• The sediment layer did form in the B20 and B5 blends made from soy oil and mixed source feed stocks The soy oil B20 had a relatively high Rancimat
stability of 5.1 hours The mix source B20 had a very low Rancimat stability
of 0.6 hours The sediment layer did not form in the palm oil B20
or B5 blends
• Low level, anti-oxidant treatment prevented the formation of the sediment layer in all of the B20 & B5 blends
• The sediment layer did not form in any of the B100 fuels or the petroleum based ULSD
14
Three Big QuestionsThree Big Questions
1. What is the sediment layer?2. How did the sediment layer form?3. If the biodiesel was oxidizing, why did
the sediment layer not form in any of B100 samples that were subjected to the same ageing stress?– Is the petro diesel involved?
• If so, how?
Please allow me to introduce you to Dr Tim McGinnis who will help us answer these
questions…………
Gas Chromatography with Mass Spectrometry (GCMS) was used toGas Chromatography with Mass Spectrometry (GCMS) was used todetermine the identity many of the compounds in the separated layerdetermine the identity many of the compounds in the separated layer
Thermo ElectronThermo ElectronTrace DSQTrace DSQ
GCMSGCMS was operated in two distinct ionization was operated in two distinct ionization modes to give the utmost information regarding modes to give the utmost information regarding the the identities identities of degradation products of FAMEof degradation products of FAME
Electron Impact IonizationElectron Impact Ionization- - Gives a “fingerprint” thatGives a “fingerprint” that
can be searched against standard spectral can be searched against standard spectral databasesdatabases
Methane Chemical IonizationMethane Chemical Ionization- Gives less fragmented ion patterns - Gives less fragmented ion patterns
which are directly related to the components’ which are directly related to the components’ molecular weightsmolecular weights
Also used were Also used were Purge and Trap Purge and Trap techniques to techniques to look at low molecular weight volatiles, and Gas look at low molecular weight volatiles, and Gas Chromatography with Flame Ionization Detection Chromatography with Flame Ionization Detection GCFIDGCFID to examine higher molecular weight to examine higher molecular weight species.species.
RT: 3.21 - 50.30
5 10 15 20 25 30 35 40 45 50Time (min)
5
10
15
20
25
30
35
40
45
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85
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100
Re
lative
Ab
un
da
nce
NL:9.72E7TIC F: MS 070108_BiodieselPrecipitate_MeCl2
Initial GCMS Initial GCMS Total Ion Chromatogram of Sediment Total Ion Chromatogram of Sediment Showing Peaks from Eluting CompoundsShowing Peaks from Eluting Compounds
• The composition of the sediment is very complex, with lots of overlap of chemical species.
• Petro diesel compounds are included, – but make up only a
fraction of the total.
• The remaining compounds with the highest concentration were found to be various polar oxygenates.
|------Molecular Weights<500----|
High Temperature GCFID Chromatogram of SedimentHigh Temperature GCFID Chromatogram of SedimentHigh capacity, thin filmed column, along with on-column injection, allows for
loading and elution of higher MW species
|--------------------------------------------------------|
Broadly Eluting Compounds with Molecular Weights Ranging from ~ 500 to 1000 (or
greater)
““SIM DIST” ColumnSIM DIST” Column
900
1000
1100
1200
1300
1400
5 10 15 20 25 30 35 40 45 50 55
GC Profile of Sediment GC Profile of Sediment vs. Analytical Standardsvs. Analytical StandardsAnalyzed Under Identical ConditionsAnalyzed Under Identical Conditions
10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42
B20 Sediment (Derivatized)
Plant Sterols
Monoolein TocopherolSoybean
OilDiolein(MAG)(DAG) (TAG)
Comparing the sediment against standards reveals that the high MW species in the sediment are at least as large as these known high MW contaminants encountered in biofuel.
Detailed analyses suggest, though, that these high MW compounds are not merely MAG, DAG, TAG, etc., and are likely more complex reaction products.
The Sediment Layer is Very Complex !The Sediment Layer is Very Complex !
We want to identify as many chemical species as possible, We want to identify as many chemical species as possible, but how?but how?
- There is a great deal of coelution of multiple components, meaning that some “peaks” contain several species. - The mass spectral “fingerprints” obtained from examining these peaks are often combinations, and therefore do not always provide useful information.
A Useful Approach . . . . .A Useful Approach . . . . .
- We can separate the sediment into fractions based on solubility in solvents with different degrees of polarity.
- We can then analyze each fraction separately to obtain more detailed information about the components present.
Solid Phase Extraction Solid Phase Extraction (SPE)(SPE)
First, sediment is injected, or “loaded” into a silica containing SPE cartridge
Non-polar Cyclohexaneis passed through
Cyclohexane solublescollected and analyzed
Next, slightly polarCyclohexane:MTBE mixis passed through
Cyclohexane:MTBEsolubles are collected and analyzed
Next, moderately polar MTBE is passed through
MTBE solubles are collected and analyzed
Finally, polar Methanol is passed through
Methanol solubles are collected and analyzed
Note: MTBE is Methyl-t-Butyl Ether
Gas Chromatographic Profile of Gas Chromatographic Profile of Non-Polar Non-Polar Fraction from Solid Phase ExtractionFraction from Solid Phase Extraction
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0-25
125
250
375
500
625
750
900mV
min
SPE Cyclohexane Elution
Primary Biodiesel Components
The bulk of thecomponents arebroad spectrumdiesel fuel.
Gas Chromatographic Profile of Gas Chromatographic Profile of Slightly Slightly Polar Polar Fraction from Solid Phase ExtractionFraction from Solid Phase ExtractionSPE Cyclohexane/MTBE Elution
0.0 10.0 20.0 30.0 40.0 50.0 60.0-25
200
400
600
800
1,000
1,200mV
min
There are no diesel fuel componentsin this fraction. All of the peaks seenare polar substances which are notsoluble in cyclohexane alone.
|------------------------|
Mostly degradationproducts from the
oxidation of biodiesel
Gas Chromatographic Profile of Gas Chromatographic Profile of Moderately Moderately Polar Polar Fraction From Solid Phase ExtractionFraction From Solid Phase Extraction
SPE MTBE Elution
0.0 10.0 20.0 30.0 40.0 50.0 60.0-25
100
200
300
400mV
min
Thought to be oxidizedbiodiesel without cleavage
|---------------------------------------|Higher MW Species
OH
O
OH
OH
Gas Chromatographic Profile of Gas Chromatographic Profile of Highly Highly Polar Polar Fraction from Solid Phase ExtractionFraction from Solid Phase Extraction
SPE MeOH Elution
0.0 10.0 20.0 30.0 40.0 50.0 60.0-25
100
200
300
400
500
600mV
min
There are significant amounts of high molecular weight species that are soluble primarily in the more polar solvents. These are not MAG, DAG, TAG, etc. They appear to be addition products (oligomers) of some of the oxidation products, which must have substantial amounts of polar functionality in their molecular structure.
|--------------------------------|
Organic Acids Detected in the B20 sedimentOrganic Acids Detected in the B20 sediment
O
OH
O
OH
O
OH
OH
O
OH
O
OH
OOH
O
O
OH
OH
Carboxylic Acids
Hydroxycarboxylic Acid
Propanoic acid
Hexanoic acid
Nonanoic acid
Palmitic acid
Oleic acid
Linoleic acid
Stearic acid
Hydroxypentanoic acid
HO OH
O O
HO
OH
O
O
OH
OO
HO
O
O
O
O
Dicarboxylic Acids
Aldehydes
Ketones
Maleic acid
Octanedioic acid
Nonanedioic acid
Butanal
Hexanal
2-Butanone
2-Heptanone
More examples of some species detected in the B20 sedimentMore examples of some species detected in the B20 sediment
OH
OO
O
O OH
OO
OH
O
O
O
O
O
OO
O
O
OO
O
Ester / Carboxylic Acid
Ester / Aldehyde
Ester / Ketone
7-Methoxy-7-oxoheptanoic acid
9-Methoxy-9-oxononanoic acid
10-Methoxy-10-oxodecanoic acid
Methoxy-8-oxooctanoate
Methoxy-9-oxononanoate
Methoxy-9-oxodecanoate
O
OO
O
O
OOH
OH
HO
O
O
OH
HO
Dimethyl Ester
Diol of Unsaturated Ester
Plant Sterol
Monoacyl Glyceride
Dimethyl nonanedioate
methyl 9,10-dihydroxyoctadecanoate
beta - Sitosterol
1-Oleoyl glycerol
HO
beta-Sitosterol
O
O
O
O
HO
diglyceride of oleic acid
OH
OH
OH
propane-1,2,3-triol
Reaction Byproducts and Natural Components Reaction Byproducts and Natural Components Detected in the B20 sedimentDetected in the B20 sediment
OH
O
(9E,12E)-octadeca-9,12-dienoic acid
OH
O
(E)-octadec-9-enoic acid
OH
O
stearic acid
OH
O
palmitic acid
How were these compounds formed?
The High Degree of Un-saturation in some FAME BioFuels, make them Particularly Susceptible to Oxidative Degradation
Note that Tallow & Rape based biodiesel contains > 50% unsaturated compounds. Oxidative degradation Note that Tallow & Rape based biodiesel contains > 50% unsaturated compounds. Oxidative degradation of animal based biodiesel can and does occur. This is an important fact that is often overlooked!of animal based biodiesel can and does occur. This is an important fact that is often overlooked!
FAME Compound
by GC/MS
FAME Type, Area %
Soy-D Soy-W Mixed
Veg.
Tallow Palm RME
16:0 Methylpalmate 8.9 11.5 15.3 23.5 44.7 9.9
16:1 Methylpalmitoleate - - - 1.6 - -
18:1 Methyloleate 38.1 34.7 34.2 43.8 37.5 59.2
18:2 Methylinoleate 43.6 47.9 22.9 12.8 5.3 26.2
18:0 Methylstearate 6.2 5.3 10.0 13.6 11.7 3.3
Other Unsaturated Compounds
3.2 0.6 17.6 4.7 0.8 1.4
O
O
Unsaturated Fatty Acid Methy Ester (FAME)
Formation of free radicals at carbons near double bonds
Attack by dissolved oxygen to form hydroperoxides
Hydrolysis of ester moiety due to entrained moisture(for both unsaturated and saturated compounds)
FAME instability can be noted asa result of a number of factors
Over time, the above mechanisms/reactions can result in a series of degradation
and addition products. These are decidedly more polar than either the parent
FAME or the diesel fuel to which it's blended. This leads to a phase separation ofthe polar materials and certain diesel components from the bulk liquid which
migrates to the bottom of the storage vessel.
The end result is a potential for ser ious applicationproblems such as deposits, plugging of fuel lines, and
engine damage!
Biodiesel (FAME) Instability In Biodiesel BlendsBiodiesel (FAME) Instability In Biodiesel Blends
• Degradation of biodiesel components can be caused by: Attack of oxygen at sites where unsaturation
(double bonds) are present, resulting in cleavage of the molecule
Hydrolysis of the ester groups due to attack by water
Both unsaturated & saturated compounds are at risk
O2 H2O
Oxygen Attack Oxygen Attack at Point of Unsaturation at Point of Unsaturation
O
O
O2
O
O
O
O
HO+
A 9 Carbon Aldehyde A 10 Carbon Fatty Acid
Secondary Oxygen AttackSecondary Oxygen Attack of the Reaction Productof the Reaction Product
O
O2
O
O
O HO
+
A 3 Carbon AcidA 6 Carbon Aldehyde
HydrolysisHydrolysis of Esters to Produce of Esters to Produce AcidsAcids
O
O
H2O
OH
O
+ CH3OH
Methyl Ester of Linoleic Acid
Free Linoleic Acid and Methanol are Produced
33
Big Q #1: What Is In This Big Q #1: What Is In This Sediment Layer?Sediment Layer?
• Products of primary & secondary oxidation • Products of hydrolysis• Complex higher molecular weight
compounds May include oligomeric compounds formed
from oxidized FAME
• Also included are other materials such as: Water, Natural impurities, Process impurities.
34
Big Q #2: How Is This Layer Big Q #2: How Is This Layer Formed?Formed?
• Sediment Layer Formation is believed to occur when the polar oxidation and hydrolysis products come together and begin to form aggregates in the less-polar petroleum based ULSD Fuel
• These aggregates can be envisioned as micro-emulsions They are dispersed within the liquid. They become unstable entities in solution due to their size,
polarity, etc. They begin to coalesce and form a separate liquid phase
which is not soluble in the Bxx.
• There is still a strong organic character to the new layer, which results in the partition inclusion of some diesel fuel and biodiesel.
35
• Further analysis revealed that many of the same aggregates were found to be present in the aged B100 samples The sediment layer did not form since the bulk B100
solution retained most of its original polarity The same sediment layer can be expected to form when
these aged B100’s sample are blended with petro based ULSD
Other system stress on oxidation product solubility - such as cold temperature, could be expected to produce a sediment layer in a Bxx blend made with non-polar fuels such as ULSDo This possibility needs further study
We plan to investigate if oxidation in raw oil feedstock can also produce these sediments
Big Q #3: Why did the sediment layer not Big Q #3: Why did the sediment layer not form in the B100?form in the B100?
Please allow me to ask Phil to return now for our summary
SummarySummary
• Biodiesel producers cannot expect all of their fuel to be consumed quickly A biodiesel producer’s long term success is
tied to the trouble free use of stored B100 or Bxx
Biodiesel stored as B100 or as Bxx will oxidize
• De-sulphurization of petro diesel increases the chance that biodiesel oxidation products will form sediment layers in Bxx and result in filter plugging issues
• Rancimat stability is not necessarily a good predictor for the formation of oxidation sediment layers in Bxx blends
- B20 & B5, made with a 5.1 hour Rancimat B100 generated a sediment layer
- B20 & B5, made with a 0.6 hour Rancimat B100 generated the same sediment layer
- B20 & B5, made with a 4.8 hour Rancimat B100 generated no sediment layer
- All of the B20 and B5 blends that were treated with a small amount of inexpensive anti-oxidant generated no sediment layer
SummarySummary
• Any B100, regardless of the measured Rancimat stability, has the potential to form this sediment layer This phenomenon may not be easily measurable
in B100 This phenomenon may not be observable until
the fuel is blended with petro diesel When biodiesel oxidizes, real potential exists for
fuel filter fouling and plugging Other issues may also result from oxidation such
as: o Injector fouling o Fouling of the Diesel Particulate Filter (DPF)o Shortened lubricating oil life
SummarySummary
To paraphrase a famous quote about Las Vegas, Nevada – the famous gambling city in the USA:
• What happens in petro diesel, stays in the petro diesel
• What happens in biodiesel, stays in biodiesel• What happens in blends of biodiesel with
petro diesel, can affect both the petro diesel refiner and the biodiesel producer because it can affect your common customer!
SummarySummary
A fully detailed report of this work is expected to be published this year in the Journal of ASTM International – Special
Issue on BioFuels
Thank you for your time!
Questions?