ching-hui tseng, nan wang eurofins qta, inc. july...
TRANSCRIPT
-
1 www.eurofinsus.com
Rapid Analysis Methods for Oils and
Biofuels Using IR/NIR Spectroscopy
Ching-Hui Tseng, Nan Wang
Eurofins QTA, Inc.
July 2013
-
www.eurofinsus.com
Biofuels
Fuel produced from renewable resources, especially plant biomass,
vegetable oils, and treated municipal and industrial wastes.
Biodiesel is made by processing vegetable oils and other fats. It
can be used either in pure form or as an additive to petroleum-based
diesel fuel.
Bioethanol is produced by fermenting the sugars in biomass
materials such as corn and agricultural residues etc. It is used in
internal-combustion engines either in pure form or more often as a
gasoline additive.
-
3 www.eurofinsus.com
Biodiesel Reaction (Trans-esterification)
-
www.eurofinsus.com
Test
Test
Test
Optimization
Segregation
Consistency
Price
Efficiency
Consistency
Quality
Glycerine
ROHOilGrease
Biodiesel
Catalyst
Biodiesel Production & Testing
Test
-
www.eurofinsus.com
Tests for Biodiesel Production
To produce quality biodiesel:
The in-coming fat/oil needs to be tested to see if pretreatment is needed
and the pretreatment outcome is satisfactory.
The trans-esterification reaction can be monitored by testing the in-
process samples.
The finished biodiesel need to meet ASTM D6751 (US) or EN14214
(Europe) standards to be used as biodiesel or blended with diesel fuel.
-
www.eurofinsus.com
Biodiesel Traditional Testing Methods --Specification for Biodiesel (B100) ASTM D6751-11a
Property ASTM Method Limits Units
Methanol EN 14110 0.2 max %mass
Water by KF D6304 0.05 %mass
Kinematic Viscosity, 40C D445 1.9 6.0 mm2/sec
Sulfur, S15 Grade D5453 15 max ppm
Cloud Point D2500 Report C
Acid Number D664 0.5 max Mg KOH/g
Free Glycerin D6584 0.020 max %mass
Total Glycerin D6584 0.240 max %mass
Oxidation Stability EN15751 3 min hours
Cetane D613 47 min
Cold Soak Filtration D7501 360 max seconds
-
www.eurofinsus.com
Biodiesel Traditional Testing Methods-Specification for Biodiesel (B100) EN14214
Property EN Method Limits Units
Methanol, EN 14110 0.2 max %mass
Water by KF EN ISO 12937 500 max mg/kg
Viscosity, 40C EN ISO 3104, ISO 3105 3.5 5.0 mm2/sec
Sulfur EN ISO 20846, EN ISO 20884 10 max mg/kg
Pour Point ISO 3016 Report C
Acid Value EN14104 0.5 max mg KOH/g
Free Glycerin EN14105, EN14106 0.020 max %mass
Total Glycerin EN14105 0.25 max %mass
Oxidation Stability, 110C EN15751/EN14112 6 min hours
Cetane EN ISO 5165 51 min
Ester Content, EN 14103 96.5 min %mass
Cold Filter Plugging Point EN 116 C
Iodine Value EN 14111 120 max g iodine/100g
Density, 15C EN ISO 3675, EN ISO 12185 860 - 900 kg/m3
-
www.eurofinsus.com
Traditional Analysis Methods of Biodiesel Production
In-coming oil:
Free fatty acids: gas chromatography (GC)
Moisture: Karl Fischer
In-Process:
Mono-, di- & tri- glycerides, total & free glycerin: GC method
Finished B100 biodiesel:
Total & free glycerin, methanol: GC method
Acid number, cloud point, moisture, oxidation stability, CFPP, density,
ester content, iodine value etc.: different equipment for each test
By-product: Glycerin
Ash: oven method
Glycerin, methanol: GC
Moisture: Karl Fischer
-
www.eurofinsus.com
Traditional Analysis Method Summary
In summary, the traditional methods
Need a laboratory with all the required instruments
Require chemists with different technical skills
Expensive and resource intensive
Time consuming
-
www.eurofinsus.com
A Desired Technology
One instrument can analyze all the materials, including feedstock,
in-process samples, finished biodiesel and by-product
Easy to operate so no specialized personnel is required
Quick and green (no chemical reagents or waste disposal)
Analyzed results are reliable
Instrument and methods are easy to maintain
10
-
www.eurofinsus.com
Infrared (IR) Spectroscopy
It has been a very powerful analytical tool for
sample identification and component analysis
since the 1960s.
-
www.eurofinsus.com
Principle of Infrared (IR) Spectroscopy
h
Low Energy High Energy
-
www.eurofinsus.com
Infrared Vibrational Energy States
Fundamental
1st Overtone
2nd Overtone
3rd Overtone
Harmonic Oscillation
Inharmonic Oscillation
Vib
rational energ
y levels
The mid-infrared (IR) covers
mostly fundamental vibrations
while the near infrared (NIR)
covers the overtone and
combination bands
-
www.eurofinsus.com
What is IR and NIR ?
Infrared (IR) spectroscopy : fundamental absorption of
molecular functional groups, 25-2.5 m (400-4000 cm-1)
Near infrared (NIR) spectroscopy : overtone or combination
absorption of molecular functional groups, 2.5-0.7 m (4000-
14,000 cm-1)
IRNIR
Ab
so
rba
nc
e
Wavenumber cm-1
Oleic Acid
NIR
MIR
-
www.eurofins.com
Electromagnetic Spectrum: Infrard is between visible and microwave regions
-
www.eurofinsus.com
MIR/NIR comparison
MIR NIR
Absorption coefficient large (higher sensitive) small (lower sensitive)
Pathlength micrometers mm to tens of cm
Sample container Salt, ATR quartz, glass
Spectrumcomplicated but unique
(can be interpreted)simple but overlapped
(hard to interpret)
Sample Gas, liquid, paste, solid (small
amount, homogeneous, e.g.
biodiesel production samples )
Liquid, paste, solid (large
amount, inhomogeneous, e.g.
bioethanol production samples)
Analyzed materialGood for organic
Possible for inorganic
Good for organic
Poor for inorganic
Available fiber optics 3 m (max.) 100 m (max.)
-
www.eurofinsus.com8/19
17
How does IR/NIR work for
the qualitative analysis?
Qualitative analysis - confirmation of incoming raw
materials, identification of unknown samples
Method - spectral matching, PCA, ANN etc.
-
www.eurofinsus.com8/19
How does IR/NIR work for the quantitative analysis?
Quantitative analysis - determination of contents of chemical composition or chemical properties.
Chemometric modeling is required: MLR, PLS, ANN
Creating Calibrations
Analyzing Samples1. Samples and data 2. Collect Spectrum 3. Build , Optimize
& Test Model
Report
Sample #081897-049
Component A 81.55%
Component B 5.38%
Component C 13.06%
1. Measure Unknown 2. Access Model3. Predict Concentrations
Component A B C
Units % % %
spectrum1 71.30 7.03 21.67
spectrum2 79.30 3.06 17.64
spectrum3 78.40 8.34 13.26
spectrum4 84.03 4.32 11.65
spectrum11 85.02 1.34 13.64
spectrum12 78.34 3.85 17.81
-
www.eurofinsus.com
Challenges of using IR/NIR
Need to find optimal instrument and sampling device for the application
Need Chemometrics and spectroscopic experts to build and maintain
methods
Need lots of representative samples and good quality primary data to
build the models
Need to have the ability to determine and resolve any issues while
using IR/NIR methods.
Needs to be user-friendly; ideally can be operated by the plant operator
-
www.eurofinsus.com
Example Solution of Overcoming These Challenges
Internet-Enabled IR/NIR
20
-
www.eurofinsus.com
Why Internet?
Monitor instrument performance remotely
Solve problems remotely
Store and distribute data automatically
Use central models for the prediction
Develop or update models remotely
Expand applications without limit
-
www.eurofinsus.com
Why Central Models?
All the application models are located at the central server
Simple analyzer with a smart brain
No instrument-specific models- one model for the same
application in different instrument
No model transfer or adjustment
Consistent prediction instrument variance compensated
Plug-and-play
No technology limit PCR, PLS, ANN etc.
Model update simultaneous for all users
-
www.eurofinsus.com
Demo of the Internet-Enabled Biodiesel Analyzer (www.QTA.com)
23
-
www.eurofinsus.com
Works behind the Biodiesel Analyzer
24/7 helpdesk service with experts monitoring and maintaining
performance
Thousands spectra of real world samples with reliable primary data
included in each calibration
Wide range of feedstocks, including soy (virgin, crude and
degummed), canola, rapeseed, poultry, tallow, choice white grease,
yellow grease, waste vegetable oil, sunflower oil, castor oil, corn,
palm, jatropha and blends thereof
Participation in ASTM PTP (Proficiency Testing Programs)
Methods underwent full round robin utilizing AOAC and ASTM
methodologies
-
www.eurofinsus.com
QTA Participation in ASTM PTP
Total Glycerine%
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
Aug-07 Nov-07 Apr-08 Nov-08 Apr-09 Aug-09
Robust Mean QTA (%)
51 L
AB
S
48 L
AB
S
47 L
AB
S
65 L
AB
S
63 L
AB
S
63 L
AB
S
Blue bar = range of accepted reference lab results for 47 65 labs
X = Mean of QTA results
= Robust Mean of reference lab
-
www.eurofinsus.com
Example Calibration Curves on Server
QTA Model Statistics
Range, % R2, % QTA Std. Error, %
0.0 0.64 93.5 0.03
QTA Model Statistics
Range, % R2, % QTA Std. Error, %
0.1 2.8 94 0.14
Total glycerin of B100 samplesMonoglycerides of in-process samples
-
www.eurofinsus.com
EQTA IR Models of Biodiesel Process
In-Process Reference Method Range Standard Error
Monoglyceride, % ASTM D6584 0.1 3.0 0.14
Diglyceride, % ASTM D6584 0.1 5.5 0.11
Tri-glyceride, % ASTM D6584 0.1 9.9 0.18
Incoming Oil Reference Method Range Standard Error
FFA, % AOCS Ca 5a-40 0.0 44.5 0.3
Moisture, % KF Moisture 0.0 1.0 0.05
Recovered Methanol Reference Method Range Standard Error
Moisture, % KF Moisture 0.0 20.0 0.5
Crude Glycerin Reference Method Range Standard Error
MeOH, % GC/FID 0.0 25.0 0.32
Glycerin, % AOCS Ea 6-94 80.0 99.9 0.9
Ash, % AOCS Ea 2-38 0.0 15.0 0.4
Moisture, % AOCS Ea 8-58 0.3 25.0 0.77
-
www.eurofinsus.com
EQTA IR Models of B100 Biodiesel Product
for ASTM D6751 and EN14214 Specifications
QTA algorithms Reference Method Range Standard Error
Free Glycerin#*, % ASTM D6584 0.00 0.03 0.004
Total Glycerin#*, % ASTM D6584 0.00 0.50 0.03
Total Acid Number#, mg KOH/g ASTM D664 0.0 1.0 0.09
Cloud Point#*, C ASTM D2500 -6.0 12.0 1.5
Moisture#, % ASTM D6304 0.0 0.1 0.09
Methanol#*, % EN14110 0.0 3.0 0.06
Oxidative Stability#, Hrs EN14112 0.5 12.0 1.5
Sulfur#, ppm ASTM D6453 0.3 16.2 1.9
Ester, % EN14103 83 99.9 0.9
Iodine Value AOCS Cd 1b-87 46 152 1.2
Density, kg/m3 ASTM D4052/D1217 873 891 1
Kinematic Viscosity, mm2/s ASTM D445 3.8 5.2 0.1
CFPP, C ASTM D6371 -14 12 1
Monoglyceride#*, % ASTM D6584 0.1 0.9 0.09
Diglyceride, % ASTM D6584 0.1 0.6 0.06
Tri-glyceride, % ASTM D6584 0.1 0.6 0.08
# AOCS Ck 2-09 standard procedure* Approved alternative methods included in the ASTM D6751
-
www.eurofinsus.com
Ethanol Production (Example: Corn Ethanol)
Corn receiving and storage
Cleaning
milling/grinding
Mixing: H2O/enzyme
--corn mash
Cooking to reduce bacterial
more enzyme --simpler sugar Fermentation
Distillation column
Molecular Sieve
Ethanol
Centrifuge
Thin stillage
Evaporator
Syrup
Solids
Rotary dryer
DDGS
-
www.eurofinsus.com
Traditional Analysis for Bioethanol Production
To ensure the quality of the bioethanol produced, quality tests are
conducted for incoming corn, processed corn in the slurry tank,
fermentation tank, DDGS (Dried Distillers Grains with Solubles)
produced.
Time consuming analytical methods have to be used to analyze
moisture, oil, protein and starch of the incoming corn.
HPLC method is commonly used to analyze carbohydrates (glucose,
maltose, maltotrios, dextrin etc.), acids (potential inhibitors), ethanol,
and other alcohols for samples from the slurry tank and the
fermentation tank.
-
www.eurofinsus.com
Protein, moisture, oil,
starch
Rejects loads of corn
on the basis of
moisture
Tracks corn suppliers
more closely
More information about
the crop for process
optimization
Using NIR for the analysis on in-coming corn
-
www.eurofinsus.com
Measure ethanol, carbohydrates, acids, and glycerol at any time period during fermentation
Quality control
Trouble shooting
Enzyme evaluations
Supplement evaluations
Using NIR for the Analysis on Corn Mash
-
www.eurofinsus.com
Typical fermenter profile
Increase in ethanol
Decrease in dextrins , maltose, dextrose
Increase in lactic acid
Increase in glycerol
Using NIR for fermenter monitoring
-
www.eurofinsus.com
A Profile of Ethanol Production during Fermentation
0
1
2
3
4
5
6
7
8
9
10
11
12
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Hours of Fermentation
% E
tha
no
l
-
www.eurofinsus.com
A Profile of Carbohydrate Reduction during Fermentation
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140
Hours of Fermentation
% C
arb
oh
yd
rate
Dextrose
Maltose
Dextrins
-
www.eurofinsus.com
A Profile of Lactic Acid Production During Fermentation
0.40
0.50
0.60
0.70
0.80
0.90
1.00
1.10
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140
Hours of Fermentation
% L
ac
tic
Ac
id
Lactic Acid is produced by the bacteria -Lactobacillus sp.
Competes with yeast for dextrose -reduce yield
Lactobacillus comes from improper cleaning of fermenters undercooked corn contaminated yeast
-
www.eurofinsus.com
A Profile of Glycerol Production During Fermentation
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140
Hours of Fermentation
% G
lyc
ero
l
Produced from yeast when under stressIncreased ethanolIncreased lactic acidHigh sugar concentrationLow pHHigh temperatureLack of nutrients (nitrogen)
-
www.eurofinsus.com
Corn Models
QTA Starch Model Statistics
Range, %DB R2, % QTA Std. Error, %DB
61.0 72.4 96.3 0.8
QTA Oil Model Statistics
Range, %DB R2, % QTA Std. Error, %DB
2.6 10.7 96.6 0.4
QTA Protein Model Statistics
Range, %DB R2, % QTA Std. Error, %DB
6.3 15.5 97.6 0.4
QTA Moisture Model Statistics
Range, % R2, % QTA Std. Error, %
7.3 24.8 99.3 0.3
-
www.eurofinsus.com
EQTA NIR Models of Corn and DDGS
Corn DDGS Range R2, % Standard Error
Oil, %DB 8.8 13.8 85.0 0.4
Protein, %DB 25.0 34.4 97.7 0.5
Moisture, % 5.4 16.6 98.3 0.5
Corn Range R2, % Standard Error
Oil, %DB 2.6 10.7 96.6 0.4
Protein, %DB 6.3 15.5 97.6 0.4
Moisture, % 7.3 24.8 99.3 0.3
Starch, % DB 61.0 72.4 96.3 0.8
-
www.eurofinsus.com
EQTA NIR Models for Biethanol Slurry Tank
Corn Mash form
slurry tank
Range R2, % Standard
Error
DP2 (maltose), % 0.18 1.57 78.0 0.18
DP3 (maltotrios), % 0.0 5.2 80.4 0.63
DP4+ (dextrin), % 0.0 24.5 97.2 1.4
Acetic Acid, % 0.002 0.030 96.4 0.004
Glucose, % 0.01 2.53 97.3 0.14
Glycerol, % 0.1 2.2 87.8 0.2
Lactic acid, % 0.01 0.88 90.8 0.07
Dextrose, % 0.08 1.1 93.4 0.09
Total Solids, % 10.0 38.5 98.5 1.1
-
www.eurofinsus.com
EQTA NIR Models for Bioethanol Fermentation Tank
Corn Mash form
fermentation tank
Range R2, % Standard
Error
Brix 10.0 27.9 99.3 0.66
DP2, % 0.18 9.20 87.5 0.95
DP3, % 0.06 2.75 90.8 0.20
DP4+, % 0.2 13.9 97.2 0.74
Ethanol, % 0.54 13.47 99.8 0.23
Glucose, % 0.0 16.1 96.9 0.78
Glycerol, % 0.1 2.0 87.8 0.16
Lactic acid, % 0.01 0.28 95.5 0.02
pH 3.7 5.7 76.9 0.23
Total Sugar, % 1.2 30.9 99.4 0.84
-
www.eurofinsus.com
Demo of the Internet-Enabled NIR Analyzer (www.QTA.com)
42
-
www.eurofinsus.com
Summary
Productions of biofuels, including biodiesel and bioethanol,
need analytical tests at different stages to ensure the
quality and yield of the products.
Traditional analytical methods are expensive, time-
consuming and need many analytical devices and skills.
Spectroscopic methods, IR/NIR, can be used to perform
rapid analysis for multiple traits but there are some
challenges when using them.
An Internet-enabled IR/NIR system has been developed
and successfully used in production plants worldwide for
the rapid analysis of biodiesel and bioethanol.
-
www.eurofinsus.com
Thank You
Question?
44