Going Green: The Analysis of BioFuels Miles S Snow Sr. Product Specialist PerkinElmer LAS [email protected]Page 2 What is Biodiesel?? Biodiesel is a clean burning alternative fuel, produced from domestic, renewable resources. • Soy bean, rapeseed, palm oil, • Rendered animal byproducts, Reclaimed cooking oil Biodiesel contains no petroleum, but it can be blended at any level with petroleum diesel to create a biodiesel blend. (B20) Biodiesel is simple to use, biodegradable, nontoxic, and essentially free of sulfur and aromatics. Biodiesel can be a direct replacement for petroleum-based diesel with little or no modification to diesel engines • Up to B20 typically requires no modification • B100 requires slight modification and has poor cold weather flow characteristics
Biodiesel is a clean burning alternative fuel, produced from domestic, renewable resources. • Soy bean, rapeseed, palm oil, • Rendered animal byproducts, Reclaimed cooking oil
Biodiesel contains no petroleum, but it can be blended at any level with petroleum diesel to create a biodiesel blend. (B20)
Biodiesel is simple to use, biodegradable, nontoxic, and essentially free of sulfur and aromatics.
Biodiesel can be a direct replacement for petroleum-based diesel with little or no modification to diesel engines• Up to B20 typically requires no modification• B100 requires slight modification and has poor cold weather
Animal fats, by-products from the production of Omega-3-fatty acids from fish oil
Rapeseeds Fruit of Palm Algae
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Biodiesel Specifications / Methods
Sulfur 50 mg/kg D5453
Sulfated ash 0.020% mass D874
Carbon residue 0.050% mass D4530
Water and sediment 0.050% vol D2709
Phosphorus content 10 mg/kg D4951
Free GlycerinGlycerol total
0.020% mass0.250% mass
D6584EN14105
Metals – monovalent,di-valent 5 mg/kg
EN14108EN14109EN14538
Alcohol 0.20% mass EN14110
= GC based test method
CharacteristicCharacteristic SpecificationSpecification Standard MethodStandard Method
= ICP/OES based method
EN 14103Esters / Linolenic Acid Ester
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Biodiesel Production
Vegetable Oil,Cooking Oils,Animal Fats
Methanol
Catalyst
Transesterification
Neutralization PhaseSeparation
Re-neutralization
MethanolRecovery
CatalystMixing
Crude Biodiesel
Purification MethanolRecovery
QualityControl
RecycledMethanol
NeutralizingAcid
Methyl Ester
PharmaceuticalGrade Glycerin
Crude Glycerin
GlycerinPurification
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Transesterification Mechanism
R1COCH2
O =
R2COCH
O =
R3COCH2
O =
+ 3 CH3OH 3 - - - - COCH3
O =
+ HOCH
CH2OH
CH2OHcatalystcatalystcatalyst
tri-glyceridestritri--glyceridesglycerides
methanolmethanolmethanol FAMEFAMEFAME
glycerolglycerolglycerol
Reaction proceeds in the presence of KOH or NaOH base
Transesterification: exchanging the alkoxy group of the ester by another alcohol. These reactions are often catalyzed by the addition of an acid or base
Water wash 4-6 times to remove glycerin, methanol and catalyst
Complete Reaction is a MUST!!! Complete wash is a MUST!!!Unreacted/ partially reacted oil and residual glycerin will cause injector coking and filter plugging
Excess CatalystInjector deposits and filter plugging
Excess AlcoholIncompatibility with gaskets and polymers, ‘cleans’ the fuel system, carrying deposits to the filter, corrosion
Ethanol can be used to create ethyl ester, but methanol is most common
Production basics…….
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The Importance of Quality…….
Acceptance of biodiesel into the market place is critical to success, the biggest hurdle to overcome is ensuring ONLY high quality biodiesel is available for sale
Final product cannot be SOLD as fuel until it passes ASTM D6751. It can be used for private use.
Two serious problems have been encountered with poor quality biodiesel- filter plugging and poor cold flow characteristic
Testing final product before use is the only way to determine functionality in the market. Quality can only be determined through laboratory testing
Manufacturers must make a commitment to QUALITY
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Biodiesel Specifications and Testing
There are standards agencies involved in setting specifications-
ASTM- American Society for Testing and Materials
and
CEN- European Committee for Standardization
ASTM has published Specification-D6751-03 “Standard Specification for Biodiesel Fuel (B100)
Blend Stock for Distillate Fuels”
Only biodiesel conforming to a standard should be considered acceptable for use
Biodiesel over the specification(0.24%) will clog fuel filtersFreeze point will be higherEffects oxidation stability
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Impact of Quality…….
Acid Number
Direct relationship with oxidative stabilityIndicator of unreacted fatty acidsCorrosion of metal parts
High Acid Number Problems-pitting & varnish
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ASTM D6584- Free and Total Glycerin by Gas Chromatography
ASTM D6584 is the main quantitative quality control method for B100 biodiesel. The method tests for glycerin, an unwanted by product of the reaction. Mono, Di, and Triglycerides, which are unreacted fatty acids remaining in the final product, also called ‘Bound Glycerin’Total Glycerin = Free glycerin + the Bound Glycerin
ASTM D6751 specifies acceptable limits0.020 % mass Glycerin0.240 % mass Total Glycerin
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Clarus 500 GC with Liquid Autosampler and programmable pressure control (PPC)TotalChrom control and data handling softwareProgrammable on Column inlet (POC)Flame Ionization Detector (FID)5ul syringe with 0.47mm OD needle
Digital flow meterElectronic leak detectorD-6584 Standards & Reagents
Inside the oven:Column- Elite 5 HT, 15 or 30 meter, 0.10 um film thickness, 0.32 mm IDHigh Temperature Guard Column, 0.53 mm diameterLow volume union or hourglass column connector – Vu2 (Restek)
Recommended GC Configuration for ASTM D6584 …..
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Instrument conditions per ASTM D6584….
Oven Ramp:• Initial- 50 degrees, hold 1.0 minutes• 15 deg/min to 180 degrees, hold 0.0 minutes• 7deg/min to 230 degrees, hold 0.0 minutes• 30 deg/min to 380 degrees, hold 10.0 minutes
Programmable On Column Inlet:Initial- 50 degreesOven tracking mode to 380 degrees
FID detector:380 degrees, 45 ml/min Hydrogen and 450 ml/min Air
Carrier Gas Flow: 3.0 ml/min Helium
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Sample Preparation, per ASTM D6584…….
Weigh 100 mg +/- 0.1 mg of biodiesel into a 10 ml septa vial
Internal Standard Addition (ISTD)Add 100 ul of 1,4 Butantriol & Tricaprin by syringe, to the vialAdd 100 ul of MSTFA (derivitizing solution)Shake solution and allow to react to for 15-20 minutes
Dilute with 8 ml of Heptane and shake to mix.
This solution is now ready for analyses!
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Laboratory SOPHeptane BlankIn 2ml autosampler vialFill with heptane, inject into GC
Calibration StandardsThis procedure is the five fold reduction in volume of the stock standardsOnly as needed, whenever recalibrating or with a new columnIn a 2ml autosampler vial200ul standard solution 1 (use disposable tip pipette)20ul ISTD1 (use 25ul syringe)20ul ISTD220ul MSTFAcap, shake, stand 30 min1.6ml heptanecap, shake, inject into GCRepeat for standard solutions 2-5
Biodiesel SamplesIn 10ml screw cap vial (or larger)tare balance with empty vial, shut doors on balanceweigh approximately 100mg of biodiesel sample, record weight (will require just over 100ul)100ul ISTD1 (use 100ul disposable tip pipette)100ul ISTD2100ul MSTFAcap, shake, stand 30min8ml heptanecap, shake, transfer to 2ml autosampler vial, inject into GC
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Supelco 44918-U Kit for Biodiesel B-100 by ASTM D6584
Calibration Standard RepackagingAccording to Supelco part # 44918-U, 1ml of each standard is used to make each calibration level. This would consume the entire contents of the calibration standards supplied. In an effort to stretch the use of the expensive calibration standards, a five fold decrease of the amounts used will allow the calibration standards to be used for multiple calibrations. This is not a dilution but a reduction in the volumes of each solution measured out into the calibration solution. The ratios must remain the same for calibration to be valid.To assist in stretching the use of the calibration standards, the original vials are repackaged into screw cap storage vials, which are then stored refrigerated until the next use.Repackage each standard, Mix1 – Mix5 into individual 2ml screw cap vials. Cap, label and store in refrigerator.Repackage each internal standard into individual 5-8ml screw cap vials. Cap, label and store in refrigerator.Option: Both internal standard solutions can be mixed together into one solution and then twice the volume can be pipetted at once. This reduces the pipetting.
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Sample Preparation, per ASTM D6584…….
Weigh 100 mg +/- 0.1 mg of biodiesel into a 10 ml septa vial
Internal Standard Addition (ISTD)Add 100 ul of 1,4 Butantriol & Tricaprin by syringe, to the vialAdd 100 ul of MSTFA (derivitizing solution)Shake solution and allow to react to for 15-20 minutes
Dilute with 8 ml of Heptane and shake to mix.
This solution is now ready for analyses!
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GC Testing ASTM D-6584…….
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Typical Chromatogram of finished product….lower glycerin
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Free Glycerin …….
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Calibration Table …….
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Monoglycerides ……. Very important to chose the right peaks
Run standard of all monoglycerides to determine actual retention times
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Monoglycerides ……. Must have the correct peaks to sum
Note: this is a named group which sums all the monos
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Diglycerides…….
Diglycerides are a summed group from approximately 20.0 – 21.0 minutes
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Diglycerides …….
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Triglycerides …….
Triglycerides are also a summed group from 22.2 – 25.2 minutes
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Reporting Results …..
The Mono- Di- and Tri- glycerides have a portion of the molecule due to glycerin structure. This is the bound glycerin. Only the glycerin portion of the glycerides are to be included in the total glycerin in the biodiesel. This requires each of the calculated glycerides to be multiplied by a factor relating to the glycerin portion prior to summing all the results.
Example, per the ASTM D6584:Glycerin 0.015 * 1.0000 = 0.015Total Monoglycerides 0.016 * 0.2591 = 0.004Total Diglycerides 0.194 * 0.1488 = 0.029Total Triglycerides 0.032 * 0.1044 = 0.003
Total Glycerin = 0.051 % mass
Make sure your data handling package can do this without exporting to some other second party software
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Complete Reporting Functionality in TotalChrom …..
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Reported results …..
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Problem areas with D6584
Complex Chromatography Many peaksUnion Connection Technique dependant/experienceMultiple pipetting Labor intensive, prone to error Peak Identification Run ALL 5 monos to prove IDCalibration Software trainingIntegration Verification Each chromatogram, time consumingShort column life Due to very high temperaturesShifting retention times Due to shortened column lifeMethod updating Software training
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Tips and Tricks ….
Results are only valuable if they are reproducible and accurate
A variety of things will affect this- weighing the sample, introduction of ISTD, water in the sample diminishes the effectiveness of MSTFA, not all MSTFA is suitable, sample carryover, column age and condition, improper integration parameters
Test your GCs reproducibility- prepare a sample of in- spec biodiesel and inject this sample 3-5 times, the more the better, and calculate the relative standard deviation (RSD), expect your results to vary 1-2 %.
Run individual monoglyceride standards to verify the retention times for summed monos. Very important.
If you experience poor reproducibility, verify that there is no sample carryover from injection to injection by running solvent betweensamples.
Ensure there are sufficient needle rinses and vials are cleanIf you have made a lot of injections replace the guard column Analytical columns typically last 250 to 500 injections
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Tips and Tricks ….
Prepare the same sample 3-5 times and inject each sample, again calculate the RSD, this should be 4% or less. This tests your sample prep and GC’s reproducibility.
Possible Problems:Weighing the biodiesel inaccuratelyPoor addition of ISTDMSTFA poor quality
Suggestions:Try increasing the sample prep 10X, use 1.0 gram of biodiesel and 1.0 ml
of ISTD and MSTFA
Record the actual weight of the biodiesel and include this in the sequence table
PRACTICE, sample preparation is technique sensitive
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Summary of Biodiesel Analyses by Gas Chromatography
Free and Total Glycerin in B100Residual Methanol (Ethanol) in Biodiesel B100• Methanol is more common: making the methyl esters• Ethanol makes the ethyl esters of the fatty acids• Analyzed by headspace
Fatty Acid Methyl Ester (FAME) Ester content• Dependant on source of feed stock
Simulated Distillation• In place of D1160 vacuum distillation
Biodiesel Blend Determination• Percent biodiesel blended into petroleum diesel• Directly influences tax break & profit• GC more accurate than IR, but slower
Methanol Testing in Biodiesel
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Residual Methanol Determination
Methanol is used in the reaction process with a catalyst to create the fatty acid methyl ester, glycerin is formed as a by product
Residual methanol and glycerin are removed by washing with water 4 to 6 times or more
Methanol can be tested by:Flashpoint
Quantification is Highly subjective and slow Infrared spectroscopy
below 1% methanol is difficult to quantitateGas Chromatography
EN14110 – Headspace GCASTM methods yet to be created
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GC Testing EN 14110 MeOH by Headspace GC…….
Europe utilizes a HS GC technique for determination of residual MeOH, this is a simple technique. No ASTM method exists yet.Most users follow EN14110 or modify EN14110.
5 g of biodiesel is added to a 20 mL HS vial, with 5 µL of 2-propanol(ISTD),or ESTD procedure is also accepted
The vial is heated and equilibrated, by the HS instrument, at 80 oC for 45 min
Manual headspace injection is allowed but automated HS injection is recommended in the EN14110 method
Any of several columns can be used, none are compatible in the same GC oven as the glycerin column due to the high temperature of the glycerin analysis, therefore a second GC is required.
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Modified Headspace Method
100ul sample instead of 5mlHeat for 10 minutes instead of 45 minutesSample measured by positive displacement pipette instead of weightExternal standardPlenty of sensitivityFine reproducibility2 minute chromatographyHigher throughputQuick, easy, precise and accurate
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The TurboMatrix Headspace Autosampler for GC
12-sample overlapping heating oven for high throughputPressure balanced injectionVery reliable and repeatable sampling
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Methanol in Biodiesel sample by HS/GC
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Calibration Curve for Methanol by EN 14110 0.01-0.5%
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Methanol by Direct Injection with POC inlet Methanol by Direct Injection with POC inlet ……....
Simplest and least expensive method, but not recommendedUtilizes same GC and Column as glycerin analysisBiodiesel sample is diluted with heptane or injected neatInternal Standard can be usedNot as accurate and slower than headspaceMethanol is unretained and therefore co elutes with any very minor unretained artifacts (biggest reason for not recommended)Probably not acceptable once ASTM method is created
Instrument ConditionsPOC inlet- 50 C initial, hold for 2 minutes, ramp to 380 CFID- 380 COven- 50 C initial, hold for 2 minutes, ramp to 380 C
Method takes approximately 9 minutes
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Chromatogram on Direct Injection
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Other GC Testing
Simulated Distillation- SimDis (ASTM D-2887)
Biodiesel has a maximum boiling point specification of 360 oC. SimDis can be used to ‘emulate’ a physical distillation and determine an equivalent boiling point distribution. Typically, Biodiesel contains carbon chains up to C24. Compounds are eluted based upon carbon number. This distribution and peak area are used in an algorithm to very accurately predict the boiling point. This is a very common test applied to crude oil.
Methanol Purity
Methanol that is fresh or recycled from production may be quality controlled for impurities.
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GC analysis for Ester content > 90% EN14103
Dilute enough to keep all methyl ester peaks on scale
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Biodiesel Blend Determination on C18:0 peak
B10 fuel
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Summary of Biodiesel Analyses by Gas Chromatography
Free and Total Glycerin in B100Residual Methanol (Ethanol) in Biodiesel B100• Methanol is more common: making the methyl esters• Ethanol makes the ethyl esters of the fatty acids• Analyzed by headspace
Fatty Acid Methyl Ester (FAME) Ester content• Dependant on source of feed stock
Simulated Distillation• In place of D1160 vacuum distillation
Biodiesel Blend Determination• Percent biodiesel blended into petroleum diesel• Directly influences tax break & profit• GC more accurate than IR, but slower
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Ethanol Biofuels Testing by Gas Chromatography
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Two Main Biofuels
0
2
4
6
8
10
12
14
Jul 06 Jan 07 Jul 06 Jan 07
bill
ion
gallo
n
Current Capacity Under Construction
Ethanol Biodiesel
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Clarus 500 GC with Liquid Autosampler and programmable pressure control (PPC)TotalChrom control and data handling softwareCapillary InjectorFlame Ionization Detector (FID)
• Ethanol 93-97%• Methanol 0.1-0.6%• Higher boiling components 3-6% total
Inside the oven:Column- Elite 1, 100-150 meter, 0.5 um film thickness, 0.25 mm ID
– Any column allowed that can give separation– Long columns = long analysis time– Some people use 30m BAC1 type column for 10 min analysis
Ethanol can be blended into gasoline E10 - E85– Pure ethanol at Indy 500
Ethanol for Fuel - ASTM D5501
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Ethanol fuel by GC/FID 100m x 250u x 0.5u RTx1-PONA
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Ethanol fuel contaminant compounds
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Summary
PerkinElmer understands the needs of the market• New, growing• Need for complete solutions
We can provide analytical solutions to help your company grow and generate profit
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Websites of Interest…..
PerkinElmerhttp://las.perkinelmer.com/
NBB- National Biodiesel Board (USA)http://www.biodiesel.org/
EBB- European Biodiesel Boardhttp://www.ebb-eu.org/biodiesel.php
Biodiesel Association of Australiahttp://www.biodiesel.org.au/
ASTM- American Society for Testing and Materialshttp://www.astm.org/cgi-bin/SoftCart.exe/index.shtml?E+mystore
