A UBURN UBURN U NIVERSITY NIVERSITY Pretreatment and Pretreatment and Fractionation of Corn Fractionation of Corn Stover with Aqueous Ammonia Stover with Aqueous Ammonia Tae Hyun Kim † , Changshin Sunwoo* and Y.Y. Le e † † Department of Chemical Engineering, Auburn Universit y, AL 36849, U.S.A. * Chemical Engineering, Chonnam National University, Gwang ju, Korea AIChE Annual Meeting Indianapolis, Indiana November 4, 2002
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Pretreatment and Fractionation of Corn Stover with Aqueous Ammonia
Pretreatment and Fractionation of Corn Stover with Aqueous Ammonia. Tae Hyun Kim † , Changshin Sunwoo* and Y.Y. Lee † † Department of Chemical Engineering, Auburn University, AL 36849, U.S.A. * Chemical Engineering, Chonnam National University, Gwangju, Korea. AIChE Annual Meeting - PowerPoint PPT Presentation
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AAUBURN UBURN UUNIVERSITYNIVERSITY
Pretreatment and Fractionation of Pretreatment and Fractionation of Corn Stover with Aqueous Corn Stover with Aqueous
AmmoniaAmmonia
Tae Hyun Kim†, Changshin Sunwoo* and Y.Y. Lee†
† Department of Chemical Engineering, Auburn University, AL 36849, U.S.A.
* Chemical Engineering, Chonnam National University, Gwangju, Korea
AIChE Annual Meeting
Indianapolis, IndianaNovember 4, 2002
AAUBURN UBURN UUNIVERSITYNIVERSITY
Tasks of Auburn Research in IFAFS Project: Tasks of Auburn Research in IFAFS Project: Pretreatment by Aqueous AmmoniaPretreatment by Aqueous Ammonia
1. Optimize the proposed pretreatment technology (reaction & operating conditions)
2. Characterize resulting fluid and solid streams
3. Close material and energy balances for each pretreatment process
4. Determine cellulose digestibility and liquid fraction fermentability
5. Compare performance of pretreatment technologies on corn stover
AAUBURN UBURN UUNIVERSITYNIVERSITY
Features of the ARP ProcessFeatures of the ARP Process
• Aqueous ammonia is used as the pretreatment reagent: Efficient delignification. Volatile nature of ammonia makes it easy to recover.
• Flow-through column reactor is used. (Ammonia Recycled Percolation)
• Versatility of the products. Ethanol Low-lignin cellulose; “filler-fiber” in paper making Uncontaminated lignin; value-added chemicals
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Processes OptionsProcesses OptionsBased on Aqueous AmmoniaBased on Aqueous Ammonia
1. ARP
2. Low-liquid ARP
3. Two-stage processing (Hot Water-ARP)
- Fractionation of corn stover
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Material and MethodsMaterial and Methods
• Corn stover supplied by NREL (1st batch used). – Common feedstock for IFAFS Project
• Ground and sieved (10 ~35 mesh).• Flow-through column reactor (SS-316, 9/10 in ID 10
in L, internal volume of 101.9 cm3) is used.
Component 1st batch 2nd batch
Glucan
Xylan
Lignin
37.5
Unit [%]
36.1
20.8
17.6 17.2
21.4
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ARP Laboratory ReactorARP Laboratory Reactor
N2 Gas
PG
Vent
Holding TankPumpPG : Press. Gauge
TG : Temp. Gauge
C.W.: Cooling Water
Aq
ueo
us A
mm
on
ia
Wa
ter
3-way v/v
#1 : For ARP
#2 : For Water or Acid
#1 #2
PG
C.W.
Oven
(Preheating Coil and Reactor)
Temp. monitoring
system (DAS)
TG
TG
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Reactor and SystemReactor and System• Reactor • System
• All reactions are carried out in a Bed-Shrinking Flow-Through (BSFT) Reactor.
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Results of ARPResults of ARP
UntreatedUntreated
80.5 36.0 10.5 1.0 10.5
0.0 37.5 20.8 0.0 0.0
[min] [%] Glucan Xylan
Deligni-fication
SolidReaction Time
20
Digestibility
60FPU 15FPU
40
83.9 35.3 9.3 1.5 11.2
82.2 36.0 10.1 1.2 10.7
60
84.7 34.5 8.9 1.6 11.790
96.0 87.9
21.2 14.3
94.4 90.2
95.1 89.2
99.6 95.0
Glucan Xylan
Liquid
• Pretreatment conditions: 15wt% of ammonia, 170C, 5mL/min of flow rate, 325psig
Note. All sugar and lignin content based on the oven-dry untreated biomass.
[%][%] [%]
FPU : FPU/g-glucan
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Effect of Reaction Time in Effect of Reaction Time in ARP PretreatmentARP Pretreatment
2)2) Lignin Lignin become bonded to the cellulose bonded to the cellulose at high temperature (Karlsson, 1997).
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ConclusionsConclusions
• Pretreatment of corn stover by ARP renders near quantitative enzymatic digestibility with 60 FPU/g-glucan and above 85% digestibilityabove 85% digestibility with 15 FPU/g-with 15 FPU/g-glucanglucan.
• It gives a high and adjustable degree of delignificdelignification (70-85%)ation (70-85%).
• Lignin contentLignin content is one of the major factors affectinaffecting the enzymatic hydrolysisg the enzymatic hydrolysis.
• Crystallinity index of corn stover increasesCrystallinity index of corn stover increases by ARP treatment due to removal of amorphous component of corn stover. Crystallinity of the glucan in corn stover is unaffected by treatment by aqueous ammonia.
ARP
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Conclusions (cont’d)Conclusions (cont’d)
• Amount of liquid throughputAmount of liquid throughput is one of the major cost factorsmajor cost factors in the ARP.
• Low-liquid ARP is as effective asas effective as the the conventional ARPconventional ARP:
• Two-stage processing of corn stoverTwo-stage processing of corn stover (hot water treatment followed by ARP) can effectively fractionate corn stovercan effectively fractionate corn stover into three main constituents.
• TheThe end product of two-stage end product of two-stage processingprocessing contains 82% glucan82% glucan, a product equivalent to a “filler fiber” used in papermaking.
Two-stage treatment
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Conclusions (cont’d)Conclusions (cont’d)
• Hot water treatment aloneHot water treatment alone at 210-220at 210-220ooCC gives unusually high digestibilityunusually high digestibility.
• Two-stage processingTwo-stage processing above 200oC increases the residual “Klason lignin”, an indication that lignin recondensationlignin recondensation and/or lignin-carbohydrate complexlignin-carbohydrate complex may occur.
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Future WorkFuture Work• Fundamental Study on ARP:
Lignin interaction with cellulasePhysico-chemical change of ARP samplesLignin recondensation and complex formation with carbohydrate
• Develop an effective method of separating lignin from the ARP reactor effluent
• Determine the ultimate ethanol yield for the ARP samples by the simultaneous saccharification and fermentation (SSF) experiments
• Design and test a proof-of-concept continuous ARP reactor.
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AcknowledgementAcknowledgement
The United States Department of Agriculture Initiative for Future Agricultural and Food Systems Program through Contract 00-52104-9663.