Transcript Slide 1

Intrinsic Characteristics of Modified
DDGS and Effective Handling
Strategies
NC -213 Meeting, February 18-19th
Kansas city, 2015
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Investigators
K-State
Kaliramesh Siliveru
USDA-ARS
Mark Casada
NDSU
Kristin Whitney
Graduate Research
Assistant
Research Agricultural
Engineer
Research Specialist
Kingsly Ambrose
Senay Simsek
Associate Professor
Assistant Professor
Rumela Bhadra
Postdoctoral Research
Associate
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Outline
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•
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•
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Introduction
Objectives
Materials and Methods
Results
Future Work
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Distillers Dried Grains with Solubles (DDGS)
Dry grinding process
Alpha amylase
Corn
Ground Cooked
Liquefaction
CO2
Fermentation
Yeast &
Glucoamylase
Distiller’s Grains
(DDG)
DDG + S
(DDGS)
Separated
Distillation
Thin stillage
Condensed
Solubles (CDS)
Ethanol
28-35% protein, 30-32% fiber & 8-12% fat (comes from CDS*/syrup), vital amino
acids, phosphorous
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DDGS and Ethanol Production
• 35.5 million MT
(2013)
• 9.7 million MT
exported
• 210 Bioethanol Plants
• Operating Capacities of
14,877.5 MG/year
ethanol
Source: Colorado Geological Survey website, updated March 2011
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Modified DDGS (M-DDGS)
• Low oil ( 4- 5% fat) DDGS
• Increased profits in oil extraction
• Around 105 dry grind ethanol plant extracted oil (USGC,
2012) (50% of plants)
• Price of crude oil is $0.45/lb
• Oil extraction investment ~ $3 million, recovery period – 3
to 4 months
Ref: Shurson, J. and B. Kerr. Reduced oil DDGS – It’s not the fat, It’s the fiber. Nutriquest DDGS
Symposium. Des Moines, IA, March 21, 2012.​
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Modified DDGS (M-DDGS)
Thin stillage
Extraction
Method 1
Crude Corn Oil
Whole stillage
CDS
Extraction
Method 2
Feed
Corn Oil
Back- end Extraction Flow Diagram
About 30% corn oil is removed from Method 1
and 60% oil is removed from Method 2
Ref: Shurson, J. and B. Kerr. Reduced oil DDGS – It’s not the fat, It’s the fiber. Nutriquest DDGS
Symposium. Des Moines, IA, March 21, 2012.​
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Flowability Problems in M-DDGS
• Caking of DDGS in rail cars;
segregation during discharge
• Economic loss: Cost to break the ‘cakes’
and unload cars
• Safety Issues
• App. $9000 in repairs (semi-annually)
• Avoiding loading hot DDGS can delay
onset of caking
(Kingsly and Ileleji, 2011)
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Objectives
• Develop heat transfer model for cooling of MDDGS pile
• Validate the developed model experimentally in a
lab scale
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Materials and Methods
Governing equation: Energy balance
𝝆𝒃𝒖𝒍𝒌 𝒄𝒃𝒖𝒍𝒌
𝝏𝑻
𝝏𝑻
𝝏
𝝏𝑻
𝝏𝑴
+ 𝝆𝒂 𝒄𝒂 𝒖𝒋
=
𝒌
+ 𝝆𝒃𝒖𝒍𝒌 𝒉𝒇𝒈
𝝏𝒕
𝝏𝒙𝒋 𝝏𝒙𝒋 𝒃𝒖𝒍𝒌 𝝏𝒙𝒋
𝝏𝒕
• Left hand side
• 1st term - energy stored at a specified period of time
• 2nd term - energy transfer due to convection
• Right hand side
• 1st term - energy transfer due to conduction (Fourier law of
heat conduction)
• 2nd term - energy liberated due to evaporation for a specific
period of time.
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Inclusion: Momentum transfer due to convection
△𝑷
𝑳
=
𝟏𝟓𝟎(𝟏−Ɛ)𝟐
𝒅𝟐𝒑 Ɛ𝟑
𝒖+
𝟏.𝟕𝟓𝝆(𝟏−Ɛ)
𝒅 𝒑 Ɛ𝟑
𝒖𝟐
• Left hand side
• Pressured drop across the length
• Right hand side
• 1st term – viscous loss coefficient
• 2nd term – inertial loss coefficient
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SIMULATION
Solved by: Finite volume method in ANSYS FLUENT
Simulations were carried out for summer (24.77 °C) and winter
(6 °C).
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Boundary Conditions
Initial condition: T = T0 = 373.15 K (at t = 0)
Energy equation:
𝜕𝑇
𝜕𝑥
=0
𝜕𝑇
𝜕𝑥
= ℎ (𝑇𝑀−𝐷𝐷𝐺𝑆 − 𝑇𝑎 )
Momentum equation:
side walls (contact with atmosphere) = interior (to allow porous media)
bottom wall (contact with concrete slab) = interface
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VALIDATION
• Low oil DDGS was heated in hot air
oven. (@ M.C 9.07% to M.C 0.89%).
• Pile dimensions: 0.20 m diameter; 0.1 m
height considering angle of repose 45°
• J- type thermocouples, FLUKE data logger
• Summer (24.77 °C) and Winter (6 °C)
• Measure of accuracy of prediction
𝑆𝐸 =
2
(𝑌−𝑌 ′ )
𝑁
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Results
Predicted and actual temperature profiles of low oil DDGS pile when cooled to 297.92 K (24.77 °C) .
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Predicted and actual temperature profiles of low oil DDGS pile when cooled to 279.15 K (6 °C) .
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Predicted Temperature Profiles for a larger pile
(A) when cooled to 297.92 (24.77 °C)
(B) when cooled to 279.15 K (6 °C) .
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Standard error of prediction (K) for the developed model
When cooled to
When cooled to
297.92 K
279.15 K
Bottom side A
0.56
1.00
Bottom mid
0.72
1.31
Bottom side B
0.55
1.32
Center side A
1.43
2.58
Center mid
2.46
2.31
Center side B
1.47
2.35
Top mid
1.32
2.73
Location
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Conclusions
• A 3-dimensional heat transfer model based on finite
volume method was developed to predict cooling pattern
of M-DDGS pile.
• The developed model predicted temperatures with
acceptable accuracy.
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Future Work
• The model will be validated with the field data which will be
collected in an industry in summer and winter seasons.
• Hopper flow analysis of M-DDGS is currently being carried
out.
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Acknowledgements
• The Andersons Research Grant Program
• POET Nutrition
• Dr. Josephine Boac- Grain Science and
Industry, K-State
Thank You!
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