bioetanol generalitati ppt.pdf
TRANSCRIPT
-
8/10/2019 Bioetanol generalitati ppt.pdf
1/134
Bio-Ethanol Production Processes
NC STATE UNIVERSITY BAE 590G 2007
Sugar Platformsugarcanesweet sorghumsugar beet
Extraction
Sugars
FermentationBeer
(~15% EtOH)
Starch Platformcorn, potatosweet potato
Saccharification
Cellulose Platform
wood, grassesagri. residues
Hydrolysis
Pretreatment
Cellulose
> 90% Ethanol
Distillation
> 99% Ethanol
Dehydration
-
8/10/2019 Bioetanol generalitati ppt.pdf
2/134
Starch-to-Ethanol Process
Hydrolysis
(C6H10O5) n + n H 2O n C 6H12O6Starch Glucose
Fermentation
C6H12O6 2 C 2H5OH + 2 CO 2Glucose Ethanol
Microbes
Amylases
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
3/134
Starch-to-Ethanol Process
Starch-rich biomass: Corn, wheat, barley, sorghum, rice, potato, sweet potato
Chemical composition:
Water Starch Proteins Fat Fiber Minerals
% % % % % %
Corn 7-16 65-70 8-10 3-5 1-1.5 1.5-2
Potato 68-85 9-25 1-3.5 0.5-1.8
SweetPotato
60-80 10-30Sugar
5%
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
4/134
Corn-to-Ethanol ProcessNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
5/134
MaterialsCorn
Enzymes: -amylase, glucoamylase
Yeast
Water: Effect of ions
Ca 2+Mg 2+
Na +
H+
Fe3+ , Fe 2+Cu 2+
Mn 2+
Zn 2+
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
6/134
Starch
200 1000 GDissolve in water at 70-80 oCIodine - Blue
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
7/134
Starch
~ 25 G/branch
Iodine - Purple
Dissolve at ~130 oC
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
8/134
Starch
-amylase Glucoamylase
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
9/134
Starch expansion and solubilization
Temperature
V i s c o
s i t y
20oC
70oC
130 oC
50oC
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
10/134
Liquefaction
Starch Oligosaccharides + Dextrins -amylase
-amylase
- Optimum conditions:
Temperature: 60 65 oC(140 - 150 oF)
- Sources:Grain malt
Bacteria Bacillus subtilis
pH 5.0 6.5
from Fungi from Bacteria
65 70 oC(150 - 158 oF)
6.0 7.5
Fungi Aspergillus spp.
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
11/134
Liquefaction
Sensitivity of -amylase to pH
4.0 5.0 10.09.08.07.06.0
pH
40oC
70oC
E n z y m e a c t
i v i t y ,
%
25
50
75
100
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
12/134
Liquefaction
Sensitivity of -amylase to temperature
50 10090807060
Temperature, oC
E n z y m e a c t
i v i t y ,
%
25
50
75
100
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
13/134
Saccharification
OligosaccharidesDextrins
Glucoamylase
- Optimum conditions:Temperature: 58 60 oC
pH 4.0 4.5
GlucoamylaseGlucose
* Saccharification can be combined with fermentation.
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
14/134
Saccharification
Effect of pH to Glucoamylase
2.0 3.0 8.07.06.05.04.0
pH
60oC
E n z y m e a c t
i v i t y ,
%
25
50
75
100
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
15/134
Saccharification
Effect of temperature to Glucoamylase
20 30 8070605040
Temperature, oC
E n z y m e a c t
i v i t y ,
%
25
50
75
100
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
16/134
Fermentation
Glucose
Yeast
- Growth conditions:
Temperature: -5 38 oC
pH 2.0 8.0
YeastEthanol + CO 2
Optimum
~ 30 oC
4.8 5.0
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
17/134
Summary of Corn-to-EtOH Process
Mashing
Mix w/ water
Temperature pH Time
~ 60 oC ~ 6.0 5-10 min
Liquefaction -amylase100-200 U/g corn
70-80o
C ~ 6.0 ~ 120 min
SaccharificationGlucoamylase~120 U/g corn
60-65 oC ~ 5.0 ~ 30 min
FermentationYeast
> 1.5 x 108/ml
30-32 oC ~ 5.0 60-72 h
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
18/134
Energy Balance
Energy input for ethanol production from corn:
Corn production:
Seeding, Fertilizers, Herbicides and Pesticides,Irrigation, Harvesting
Corn-to-EtOH process
Transportation, Grinding,Heat in Mashing and Hydrolysis,(-) Heat recovery from fermentation,Distillation, Dehydration, Residue Management
-
8/10/2019 Bioetanol generalitati ppt.pdf
19/134
Cellulose-to-Ethanol ProcessCellulosic biomass:
Woody biomass (trees):
Pine, aspen, willow, etc.
Herbaceous biomass (grasses):
Switch grass, Bermuda grass,corn stover, wheat straw, etc.
Waste cellulosic materials:Waste paper,solid waste, etc.
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
20/134
Cellulose-to-Ethanol ProcessEnzymatic hydrolysis (saccharification)
(C6H10O5) n + n H 2O n C 6H12O6Cellulose Glucose
FermentationC
6H
12O
62 C
2H
5OH + 2 CO
2Glucose Ethanol
Microbes
Cellulases
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
21/134
Major Composition
Cellulose Hemicellulose Lignin
Hardwood stems 40 - 55% 24 - 40% 18 - 25%
Softwood stems 45 - 50% 25 - 35% 25 - 35%
Switchgrass 45% 31% 12%
Costal Bermuda grass 35% 22% 20%
Corn stover 39% 22% 21%
Wheat straw 30% 50% 15%
White paper 85 - 99% 1 - 15%
Newspaper 40 - 50% 25 - 40% 18 - 30%
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
22/134
Cellulose StructureNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
23/134
Cellulose Structure
Source: Hopkins, W.G., 1999. Introduction to Plant Physiology, second edition. John Wiley & Sons, Inc., New York.Source: Hopkins, W.G., 1999. Introduction to Plant Physiology, second edition. John Wiley & Sons, Inc., New York.
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
24/134
Hemicellulose Structure
A complex, heterogeneous mixture of sugars and sugarderivatives that form a highly branched network.
X X X X X X X X X2 3
4--Me- -D-GA 11 -L-A
X X: -1,4-linked D-xylopyranose unitsMe: methoxy groupGA: glucuronic acidA: esterified- -L-arabinofuranose
side chain
Arabinoxylan
The monomers include hexoses (glucose, galactose, andmannose) and pentoses (arabinose and xylose).
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
25/134
Lignin
A complex polymer: Branched polymer/polydisperse
Hold the fibers together
Provide support for the trees and grasses
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
26/134
Lignin Structure
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
27/134
Structure of Lignocellulosic Biomass
Source: Hopkins, W.G., 1999. Introduction to Plant Physiology, second edition.
John Wiley & Sons, Inc., New York.
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
28/134
PretreatmentPurpose:
Remove lignin and/or hemicellulose
Reduce crystallinity of the cellulose
Increase the porosity of the materials
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
29/134
Pretreatment
Requirements:
Improve the formation of sugars or the ability to subsequentlyform sugars by hydrolysis
Avoid the degradation or loss of carbohydrates
Avoid the formation of byproducts inhibitory to thesubsequent hydrolysis and fermentation
Be cost-effective
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
30/134
Pretreatment TechnologyPhysical Pretreatment
Mechanical comminution:
Chipping to: 10 30 mm
Grinding or milling to: 0.2 2 mm
NC STATE UNIVERSITY BAE 590G 2007
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
31/134
Pretreatment TechnologyPhysico-chemical Pretreatment
Steam explosion:
ChippedLignocellulosic
Biomass
Steam
160 260 oC0.69 4.83 atm
A few seconds to a few minutes
Swiftly release pressure toatmosphere
NC STATE UNIVERSITY BAE 590G 2007
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
32/134
Steam Explosion:
CelluloseLignin
Hemicellulose
Pretreatment
Ladisch, 2006
NC STATE UNIVERSITY BAE 590G 2007
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
33/134
Steam Explosion:
@ high temperature,
Hemicellulose degraded
Lignin transformedExample:
Untreated Poplar chips: Hydrolysis efficiency 15%
Treated Poplar chips: Hydrolysis efficiency 90%
Advantage:
70% less energy compared to mechanical treatment
Disadvantage:
Generation of inhibitory compounds to microbes
NC STATE UNIVERSITY BAE 590G 2007
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
34/134
Physico-chemical Pretreatment
Ammonia Fiber Explosion (AFEX):
ChippedLignocellulosicBiomass
LiquidAmmonia
90 oCHigh Pressure
~ 30 min Swiftly release pressure to
atmosphere
Ammonia vapor recovery
Compressor
NC STATE UNIVERSITY BAE 590G 2007
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
35/134
Ammonia Fiber Explosion (AFEX):
CelluloseLignin
Hemicellulose
Pretreatment
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
36/134
Ammonia Fiber Explosion (AFEX):
Tremendously increase the porosity
Keep the composition essentially the same
Do not generate inhibitory compoundsSignificantly reduce the crystallinity of the cellulose
Works well on low-lignin biomass such as grasses but not efficiently on high-lignin biomass such as woods
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
37/134
CO 2 Explosion:
Physico-chemical Pretreatment
High Pressure
Short time
ChippedLignocellulosicBiomass
CO 2
Swiftly release pressure toatmosphere
Relative low efficiency compared to Steam Explosion and AFEXLess expensive than AFEX
Do not generate inhibitory compounds
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
38/134
Ozonolysis:
Chemical Pretreatment
Ozone removes ligninslightly attacks hemicellulosehardly affect cellulose
Disdvantage: Cost
Advantages:
Effectively remove ligninDo not generate inhibitory compounds
Reactions at room temperature and atmospheric pressure
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
39/134
Acid hydrolysis
Chemical Pretreatment
Concentrated H 2SO 4 and HCl can be used for hydrolysis,
but they are corrosive and hazardous, and must be recovered.Dilute acid pretreatment:
H2SO 4: 1.0 1.5%
- Degrade hemicellulose- Reduce crystallinity of cellulose
@ low solid loading (5 10 %)
120 160 oC for 15 60 min@ high solid loading (10 40 %)
160 190 oC for 5 30 min
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
40/134
Dilute acid pretreatment for coastal Bermuda grass
Bermudagrassarabinan
4.3%galactan
1.1%
xylan19.4%
ash4.2% glucan32.4%
other 18.3%
acid-insoluble
lignin20.3%
Sun and Cheng, 2005
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
41/134
H 2SO 4 (%)
0.5 0.7 0.9 1.1 1.3 1.5 1.7
T o t a l r e
d u c i n g s u g a r s
( m g / g )
80
160
240
320
400
480
30 min60 min
90 min
H 2SO 4 (%)
0.5 0.7 0.9 1.1 1.3 1.5 1.7
X y l o s e
( m g / g )
0
40
80
120
160
Dilute acid pretreatment for coastal Bermuda grass
Sun and Cheng, 2005
Coastal Bermuda grass prehydrolyzate composition
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
42/134
Alkaline hydrolysis (NaOH, lime)
Chemical Pretreatment
Principle:
Break the intercellular bonds crosslinking hemicelluloseand other compounds (lignin and cellulose)
Results:
Increase porosity and internal surface areaDecrease in the degree of polymerization
Decrease crystallinity
Separate lignin, hemicellulose, and celluloseDisrupt the lignin structure
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
43/134
Organosolv process
Chemical Pretreatment
Use organic solvents to break the internal lignin-
hemicellulose bonds at high temperature (> 185 oC)
Organic solvents:
methanol, ethanol, acetone, ethylene glycoloxalic and salicylic acids
@ low temperature, the organic solvents have to be usedtogether with inorganic acid such as H 2SO 4 and HCl.
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
44/134
Fungal treatment
Biological Pretreatment
Microbes: brown-, white-, and soft-rot fungi
Brown-rot fungi attack cellulose
White- and soft-rot fungi attack lignin and cellulose
Some white-rot fungi produce lignin-degradingenzymes such as lignin peroxidases
Advantage: Inexpensive
Disadvantage: Time-consuming
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
45/134
Enzymatic Hydrolysis
(C6H10O5) n + n H 2O n C 6H12O6
Cellulose Glucose
Cellulases
Cellulase (Endoglucanase)
Cellobiohydrolase (Exoglucanase)
-Glucosidase
Cellulases: -(1 4) glycoside hydrolases
Low cost compared to acid or alkaline hydrolysis
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
46/134
Enzymatic Hydrolysis
Exoglucanase
Cellobiose
Cellulose
-Glucosidase
Glucose
Endoglucanase
Cello-oligosaccharides
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
47/134
Cellulolytic EnzymesCellulase (Endoglucanase)
Randomly attack the -(1, 4) glycosidic bonds of cellulose
Rapidly decrease the viscosity of cellulose solution
Normally act on only amorphous cellulose not crystallinecellulose
Can be produced from fungi and bacteria
Optimum reaction conditions depend on the sourceorganism
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
48/134
Cellulase (Endoglucanase)
Microbes that produce cellulase and its properties
Fungi
Aspergillus sp.
pH (optimum) Temp.
2-9 (4-5) 45-70 oC
P. chrysosporium 3-6 (4-5) 40-50o
CTrichoderma sp. 5-9 (5) 50-65 oC
Humicola sp. 3.5-9.5 (5) 50-65 oC
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
49/134
Microbes that produce cellulase and its properties
Bacteria pH (optimum) Temp.
Cellulase (Endoglucanase)
Bacillus sp. 4-10 (4.5-7) 60-70 oC
Clostridium sp. sp. 5-7 (6-6.5) 60-70 oC
Pseudomonas sp. 7-8 (8)
Ruminococcus sp.
Streptomyces sp.
Thermomonospora sp.
ll l lNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
50/134
Cellobiohydrolase (Exoglucanase)
Cellulolytic Enzymes
Release cellobiose from the non-reducing ends of a
cellulosic substrateHydrolyze both amorphous and crystalline cellulose
Generally do not hydrolyze substituted cellulose such as
carboxymethyl cellulose
Mainly from fungi
It was found recently that some bacteria can alsoproduce cellobiohydrolase
ll b h d l ( l )
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
51/134
Microbes that produce cellobiohydrolase and its properties
Fungi
Coniophora sp.
pH (optimum) Temp.
5.0 50 oC
Humicola sp. 5.0 50o
C Penicillium sp. 4.5 60 oC
Fusarium sp. 5.0 50 oC
Cellobiohydrolase (Exoglucanase)
Trichoderma sp. 5.0 80 oC
C ll l l i ENC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
52/134
-Glucosidase
Cellulolytic Enzymes
Degrade cellobiose into glucose
Very broad specificity to both glycon and aglycon substratessuch as steroid -glucosides and -glucosylceramides ofmammals, compared to cellulase and cellobiohydrolase
Provide the source of energy and C in the form of glucoseto the host microorganisms
Improve hydrolysis efficiency by degrading cellobiose,
the end-product and competitive inhibitor ofcellobiohydrolase and cellulase
Gl id
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
53/134
Microbes that produce -Glucosidase and its properties
Fungi
Aspergillus sp.
pH (optimum) Temp.
4.5-5.0 65 oC
Humicola sp. 5.0 50o
C Penicillium sp.
Candida sp. 6.8
Saccharomyces sp. 6.8 45 oC
-Glucosidase
Trichoderma sp. 6.0-6.5
Gl id
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
54/134
Microbes that produce -Glucosidase and its properties
Agrobacterium sp.
Bacteria pH (optimum) Temp.
Ruminococcus sp. 6.5 30-35o
C
-Glucosidase
Clostridium sp. 6.0 65 oC
Streptomyces sp. 6.5 50 oC
Other EnzymesNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
55/134
Xylanases
Other Enzymes
Attack -(1,4) bonds between D-xylose residues ofheteroxylans and xylo-oligosaccharides
Do not degrade xylobiose
Endo-acting enzyme
Other EnzymesNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
56/134
-Xylosidase
Hydrolyze xylo-oligosaccharides to xylose
Not active on xylan
Other Enzymes
Improving Enzymatic HydrolysisNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
57/134
Factors affecting enzymatic hydrolysis:
Substrates
Cellulase enzyme activities
Reaction conditions: Temperature, pH, etc.
Improving Enzymatic Hydrolysis
Improving Enzymatic HydrolysisNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
58/134
Substrates
Improving Enzymatic Hydrolysis
@ low substrate level, increase of substrate conc.increases the hydrolysis rate.
Optimal substrate load depends on the source ofcellulose and enzymes
Another disadvantage of cellulosic materials
Improving Enzymatic HydrolysisNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
59/134
Enzyme dose and combination
Cellulase dose: range 7 33 FPU/g substrate
1 FPU (filter paper unit) = 1 micromole of reducing sugaras glucose produced by 1 ml of enzyme per minute
Usual cellulase dose: 10 15 FPU/g substrate
Improving Enzymatic Hydrolysis
Use enzyme mixture addition of -Glucosidase
Enzymatic Hydrolysis of BermudagrassNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
60/134
Time (h)
0 10 20 30 40 50 60 70 80
G l u c o s e
( m g / g b i o m a s s )
0
20
40
60
80
100
120
140
160
180
0 CBU, 5 FPU
25 CBU, 5 FPU50 CBU, 5 FPU
Enzymatic Hydrolysis of Bermudagrass1 CBU (cellobiase unit) = 1 mol of cellobiose thatis converted into glucose per minute withcellobiose as a substrate
Sun and Cheng, 2004
Enzymatic Hydrolysis of Rye StrawNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
61/134
Time (h)
0 10 20 30 40 50 60 70 80
G l u c o s e
( m g / g
b i o m a s s )
0
20
40
60
80
100
120
140
160
0 CBU, 5 FPU25 CBU, 5 FPU50 CBU, 5 FPU
Enzymatic Hydrolysis of Rye Straw
Sun and Cheng, 2004
Enzymatic Hydrolysis of BermudagrassNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
62/134
Time (h)
0 10 20 30 40 50 60 70 80
C e l l o
b i o s e
( m g / g
b e r m u
d a g r a s s
)
0
8
16
24
32 0 CBU, 5 FPU
0 CBU, 10 FPU0 CBU, 15 FPU25-50 CBU, 5-15 FPUcontrol
Enzymatic Hydrolysis of Bermudagrass
Sun and Cheng, 2004
Improving Enzymatic HydrolysisNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
63/134
Improving Enzymatic Hydrolysis
Simultaneous Saccharification and Fermentation(SSF)
Mixture of Microorganisms:
Fugus T. reesei for hydrolysis or saccharification
Yeast S. cerevisiae for fermentation
Optimal T: 38 oC compromise between optimal Tfor hydrolysis (45-50 oC) andfermentation (30 oC)
Cost ReductionNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
64/134
Cost Reduction
Utilization of hemicellulose and lignin
Fermentation of pentose to ethanol
Gasification of lignin and hemicellulose
Recycle of enzymes
Ethanol Production: Fermentation
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
65/134
Overall Reactions:
C6H12O6 + 2ADP
Glucose
2C 2H5OH + 2CO 2 + 2ATP + 10.6kJ
Ethanol
Enzymes
180 g 92 g
Ethanol Production: Fermentation
S gar Catabolism Gl col sis EMP Path a
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
66/134
Sugar Catabolism Glycolysis EMP Pathway
OH
HO
OH
H
H
HH
OHOH
CH 2O
Glucose-6-phosphate(product)
P
OH
HO
OH
H
H
HH
OHOH
CH 2OH
Glucose(substrate)
1
ATP ADP
Glucokinase(enzyme)
(Adenosine Triphosphate)
(Adenosine Diphosphate)
Sugar Catabolism Glycolysis EMP Pathway
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
67/134
Sugar Catabolism Glycolysis EMP Pathway
Phosphoglucoseisomerase
OH
HO
OH
H
H
HH
OHOH
CH 2O
Glucose-6-phosphate
P
2
H
HO
O
OH
HOHOH
CH 2OHP OCH 2
Fructose-6-phosphate
Sugar Catabolism Glycolysis EMP Pathway
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
68/134
Sugar Catabolism Glycolysis EMP Pathway
Fructose-1,6-bisphosphatase
3
H
HO
O
OH
HOHOH
CH 2OP OCH 2
Fructose-1,6-bisphosphate
H
HO
O
OH
HOHOH
CH 2OHP OCH 2
Fructose-6-phosphate
PATP ADP
Sugar Catabolism Glycolysis EMP Pathway
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
69/134
Sugar Catabolism Glycolysis EMP Pathway
Fructose-1,6-bisphosphate
adolase
4
HHO
O
OH
HOHOH
CH 2OP OCH 2
Fructose-1,6-bisphosphate
P CH 2O
C = O
CH 2OH
P
+
CH 2O
H C OH
H C = O
P
Dihydroxyacetone phosphate
Glyceraldehyde3-phosphate
Sugar Catabolism Glycolysis EMP Pathway
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
70/134
Sugar Catabolism Glycolysis EMP Pathway
5
CH 2O
C = O
CH 2OH
P CH 2O
H C OH
H C = O
P
Dihydroxyacetone phosphate
Glyceraldehyde3-phosphate
Triose phosphateisomerase
(96%) (4%)
Sugar Catabolism Glycolysis EMP Pathway
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
71/134
Sugar Catabolism Glycolysis EMP Pathway
6
CH 2O
C = O
CH 2OH
P CH 2O
H C OH
C = O
P
Dihydroxyacetone phosphate 1,3-Diphosphoglycerate
NAD + NADH
O P
Nicotinamideadenine
dinucleotide(Reduced form)
Glyceraldehyde3-phosphate
dehydrogenase
Sugar Catabolism Glycolysis EMP Pathway
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
72/134
Sugar Catabolism Glycolysis EMP Pathway
7
CH 2O
H C OH
C = O
P
1,3-Diphosphoglycerate
O P
CH 2O
H C OH
C = O
P
OHPhosphoglycerate
kinase
ADP ATP
3-Phosphoglycerate
Sugar Catabolism Glycolysis EMP Pathway
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
73/134
Sugar Catabolism Glycolysis EMP Pathway
8
CH 2OH
H C O
C = O
P
OH
Glycerophosphate
mutase
2-Phosphoglycerate
CH 2O
H C OH
C = O
P
OH
3-Phosphoglycerate
Sugar Catabolism Glycolysis EMP Pathway
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
74/134
g y y y
9
CH 2
C O
C = O
P
OHEnolase
2-Phosphoenolpyruvate
CH 2OH
H C O
C = O
P
OH
2-Phosphoglycerate
H2O
Sugar Catabolism Glycolysis EMP Pathway
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
75/134
g y y y
10
CH 2
C O
C = O
P
OH
2-Phosphoenolpyruvate
CH 2
C OH
C = O
OHPyruvate
kinase
ADP ATP
Enolpyruvate
Sugar Catabolism Glycolysis EMP Pathway
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
76/134
g y y y
11
CH 3
C = O
C = O
OH
Pyruvate
kinase
Pyruvate
CH 2
C OH
C = O
OH
Enolpyruvate
Sugar Catabolism Glycolysis EMP Pathway
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
77/134
g y y y
12
CH 3=
O
Py ruva teC OH
= O
C
CH 3 CH 2OH
Ethanol
Alcoholdehydrogenase
NAD +
NADH + H +
CH 3=
O
CHAcetaldehyde
CO 2
Py r u va ted eca r b oxyla se
CH 3=
O
C OH
Acetate
Tricarboxylic Acid(TCA) Cycle
Fermentation By-products
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
78/134
CH 2O
C = O
CH 2OH
P CH 2O
H C OH
C H 2OH
P
Dihydroxyacetone phosphate
-Phosphoglycerol
NAD+
NADH 2
-Phosphoglyceroldehydrogenase
CH 2OH
H C OH
C H 2OH
Phospholipase
Glycerol
Glycerol1
Fermentation By-products
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
79/134
Acetic Acid 2
CH 3 CH 2OH + H 2O CH 3 COOH + 2H 2
Acetogenic bacteria
Ethanol Acetic Acid
CH 3 CH 2OH + O 2 CH 3 COOH + H 2O Acetobacter
Fermentation By-products
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
80/134
Butyric Acid 3
C6H12O6
Glucose
2CH 3CH 2CH 2COOH + CO 2 + 2H 2 + 61.44kJ
Butyric Acid
Clostridia
Fermentation By-products
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
81/134
Other alcohols4
n-Propanol
iso-Butanol
iso-Pentanol
Methanol
Tricarboxylic Acid (TCA) Cycle or Citric Acid Cycle
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
82/134
http://en.wikipedia.org/wiki/Citric_acid_cycle
Microbiology of Ethanol Fermentation
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
83/134
Microorganisms in ethanol fermentationYeasts Sacchromyces cereviciaeBacteria
Microorganism Growth RequirementCarbonEnergy
Nutrients
YeastNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
84/134
HistoryYeast Cell Composition
Water 80%
Dry matter 20%C 50%O 30-35%
N 5%
H 5%P 1%Mineral 5-10%
or Proteins 40-45%carbohydrates 30-35%
Nucleic acids 6-8%lipids 4-5%
Yeast Morphology
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
85/134
Yeast Cell Structure
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
86/134
Yeast Cell Structure
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
87/134
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
88/134
YeastCellCycle
Fermentation
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
89/134
Glucose
Yeast
- Growth conditions:
Temperature: -5 38o
C pH 2.0 8.0
YeastEthanol + CO 2
Discussion: T; pH
Optimum
~ 30o
C4.8 5.0
Yeast PropagationNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
90/134
Carbon source:Glucose, maltose, etc.
Nitrogen source: Need ammonium or organic N
(NH 4)2SO 4, (NH 4)3PO 4, urea
Phosphorus source:
Need P mainly at early fermentation.
Need small amount, usually enough from raw starch
materials such as corn or other grains. Addition of P is needed when sugar beet is used.
Lab Yeast PropagationNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
91/134
Slope Culture
10 ml Test Tube Yeast extract, peptone glucose (YEPG)
28 - 30 oC; 24 hours
250 ml Flask YEPG28 - 30 oC; 15 - 20 hours
3,000 ml flask Saccharification product28 - 30 oC; 15 - 20 hours
Yeast Propagation in Production
1 10 20
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
92/134
Lab yeast culture Fermentation seed tanks1 : 10-20
Discussion:
Hygiene is extremely important in yeast propagation to prevent the fermentation from contamination.
Medium: Saccharides
Measures: Disinfection Restricted personnel access Filtration of air in the room
Fermenter for EtOH Produc.
New Techniques on Yeast
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
93/134
High temperature yeast: 40-50 oC
- Dont need heat exchange
- Possible to combine saccharification and fermentation
Ethanol-tolerant yeast:
Normal yeast: 10-12% (v) EtOH
18-20% (v) EtOH
Genetically engineered yeast: directly convert starch to EtOH
New Techniques on YeastNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
94/134
Active Dry Yeast
Normally, yeast contains ~ 80% water.
Under rapid vacuum drying at 50-60oC, water content
can be reduced to 5%.
Active dry yeast has to be vacuum packed to keep it activity
Active dry yeast: 30 40 billion cells/g
Immobilized yeast fermentation
Heat ProductionNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
95/134
C6H12O6 + 2ADP
Glucose
2C 2H5OH + 2CO 2 + 2ATP + Heat
Ethanol
Yeast
180 g 92 g2P i
Overall net heat production for all stages: 157 kJ/mole
Energy storage in ATP: 2 x 31 = 62 kJ
Overall heat can be produced: 157 + 62 = 219 kJ/mole
Energy Balance
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
96/134
Energy production from combustion of ethanol:
1 Kcal = 4.18 kJ = 3.97 B.t.u.
C2H5OH + 3O 2 2CO 2 + 3H 2O + 326 Kcal/mole
46 g
Ethanol Fermentation Technology
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
97/134
Batch fermentation
Operation: Reactor disinfection
Add substrate, yeast culture, and nutrients
Fermentation
SeparationFementer
Batch Fermentation
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
98/134
Advantages:
Simple system and easy to operate
Less chance for contamination
Disadvantages:
Low efficiency
Changing environment for yeast
Ethanol Fermentation Technology
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
99/134
Fed-batch fermentation
Yeast, nutrients, and some substrate are added at the beginning, and more substrate is added in several times.
Fementer
Ethanol Fermentation Technology
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
100/134
Continuous fermentation
Fementer
Substrate
Product NutrientsOperation:
Reactor start-up
Steady-state operation
Continuous fermentation
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
101/134
Advantages:
High efficiency
Easy for automation
Disadvantages:
Challenge to protect from contamination
Stable environment for microbes
Control of Ethanol Fermentation
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
102/134
Temperature
Optimum T for Yeast ( Sacchromyces cereviciae ) growthand fermentation:
28 32 oC or 82 - 90 oF
Fermentation produces heat, so heat exchanger is usuallyneeded to maintain an optimal T
Protection from contamination
Distillation and DehydrationNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
103/134
Ethanol concentration in fermentation beer: 10-20%
Fuel ethanol: > 99%
Distillation: Ethanol: 10-20% < 93%
Dehydration: Ethanol: < 93% > 99%
Distillation
Bubble Point and Dew Point
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
104/134
Bubble Point and Dew Point
@ 1 atm, water is boiling at 100 oC
Water
Heat
25oC Water
Heat
Water vapor
100 oC
Heat
Water
vapor 100 oC
Distillation
When you have two liquid
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
105/134
Examples: Water EthanolBenzene - Toluene
When you have two liquidcompounds that can becompletely dissolved in each
other at any ratio, the physicalproperties of the solution can bedifferent from a single liquidcompound.
A+B
Phase Equilibrium
120
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
106/134
AB0.0 0.2 0.60.4 0.8 1.0
T e m p e r a t u r e , o
C
x = mole fraction of A in liquidy = mole fraction of A in vapor
60
70
80
90
100
110
120
Bubble-point curve
Dew-point curve
x=0.32 y=0.68
IdealSolution
Phase Equilibrium
y=x Ideal solutiono r
1.0
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
107/134
Henrys Law
pA = y e P = H Axe
0.0 0.2 0.60.4 0.8 1.0 y = m o l e
f r a c t
i o n o f
A i n v a p o
x = mole fraction of A in liquid
0.2
0.4
0.6
0.8
AB
Raoults Law
pA = y eA P = p AxeA
pB = y eB P = p BxeB
0
0
Phase Equilibrium: Azeotropic mixture
80
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
108/134
A(Benzene)
B(EtOH)
0.0 0.2 0.60.4 0.8 1.0
T e m p e r a t u r e , o
C
x = mole fraction of A in liquidy = mole fraction of B in vapor
60
65
70
75
t b = azeotropic point
x
y
Phase Equilibrium: Azeotropic mixture
o r1.0
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
109/134
0.0 0.2 0.60.4 0.8 1.0 y = m o l e
f r a c t
i o n o f
A i n v a p o
x = mole fraction of A in liquid
0.2
0.4
0.6
0.8
A (Benzene)B (EtOH)
ya
xa
ya = x a
100
Phase Equilibrium: Ethanol WaterNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
110/134
A(EtOH)
B(H 2O)
0.0 0.2 0.60.4 0.8 1.0
T e m p e r a t u r e , o
C
x = mole fraction of A in liquidy = mole fraction of B in vapor
70
75
80
90
85
95
78.5 oC
Phase Equilibrium: Ethanol Water
a p o r 1.0
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
111/134
0.0 0.2 0.60.4 0.8 1.0 y = m o l e
f r a c t
i o n o f
E t O H i n v a
x = mole fraction of EtOH in liquid
0.2
0.4
0.8
EtOHH 2O
0.6
xa=0.84
Distillation: Ethanol Water mixture
100
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
112/134
A(EtOH)
B(H 2O)
0.0 0.2 0.60.4 0.8 1.0
T e m p e r a t u r e , o
C
x = mole fraction of A in liquidy = mole fraction of B in vapor
70
75
80
90
85
95
78.5 oC
Distillation: Ethanol Water mixture
C li WCondenser
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
113/134
Fractionating
Column
EtOH-H 2OMixture
Bottom Product
Overhead Product
SteamReboiler
Cooling Water
R e c t i f y i n g
S e c t i o n
S t r i p p
i n g
S e c t i o n
Reflux
D, x D Total mass balance: F = D + B
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
114/134
FractionatingColumn
EtOH-H 2OMixture
F, x F
B, x B
S t r i p p i n g
R e c t i f y i n g
EtOH mass balance: F x F = D x D + B x B
Thus,
DF
xF - xBxD - xB
=
BF
xD - xFxD - xB
=
Operating Lines
D, x D c t i f y i n g
L Total mass balance: Vn+1 = D + L n
EtOH mass balance: V y = D x + L x
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
115/134
n
n+1F, x F
FractionatingColumn
EtOH-H 2OMixture B, x B
S t r i p p
i n g
R e
c
Vn+1 , yn+1Ln, xn
EtOH mass balance: Vn+1 yn+1 = D x D + L n xn
Thus,L
nD + L n
yn+1 = x n +D x
DD + L n
Heat (T difference between plates and latent heatof vapor) balance for all the liquid and vapor at plate n will determine L n and Vn+1 .
Assume:
Latent heats >> other heatsLatent heats of the components in are close
Then, L n = L n-1 = = L
- Operating line for rectifying section
D, x D c t i f y i n g
LSimplified Operating line:
Operating Lines
LD + Lyn+1 = x n +
D x DD + L
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
116/134
FractionatingColumn
EtOH-H 2OMixture
F, x F
B, x B
S t r i p p
i n g
R e
n
n+1
Vn+1
, yn+1
Ln, x
n
D + Lyn+1 n D + L
Reflux Ratio R D:R D =
L
DThen:R D
R D + 1y = x +
xDR D + 1
or L
D + Ly = x +
D x DD + L
Top Plate: y = x = x D
Distillation: Example
1.0 xD = 0.8If R D = 2.0
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
117/134
0.0 0.2 0.60.4 0.8 1.0 y = m o l e
f r a c
t i o n o f
E t O H i n
v a p o r
x = mole fraction of EtOH in liquid
0.2
0.4
0.8
EtOHH 2O
0.6
xa=0.84
D
XDR D + 1
= 0.27
Then
Operating Line
- y axis intersect
Operating LinesTotal mass balance: Lm = V m+1 + B
EtOH mass balance: Lm xm = V m+1 ym+1 + B x BD, x D
i f y
i n g L
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
118/134
mm+1 Vm+1 , y m+1
Lm, xm
Thus,Lm
Lm - By
m+1= x
m-
B x B
Lm - B- Operating line for stripping section
Temperature in reboiler determines xB and yr
FractionatingColumn
EtOH-H 2OMixture
F, x F
B, x B
S t r i p p
i n g
R e c t i
yr
xB
A(EtOH)
B(H 2O)
0.0 0.2 0.60.4 0.8 1.0
T e m p e r a t u r e , o
C
x = mole fraction of A in liquidy = mole fraction of B in vapor
70
75
80
90
100
85
95
Distillation: Example
1.0xD = 0.8If R D = 2.0
S d
NC STATE UNIVERSITY BAE 590G 2007
R
-
8/10/2019 Bioetanol generalitati ppt.pdf
119/134
0.0 0.2 0.60.4 0.8 1.0 y = m o l e
f r a c
t i o n o f
E t O H i n
v a p o r
x = mole fraction of EtOH in liquid
0.2
0.4
0.8
EtOHH 2O
0.6
xa=0.84
XDR D + 1
= 0.27Then
Operating LineIf T reboiler = 98 oC
Then xB = 0.02
If feed xF
= 0.18
Saturatedliquid feed
If saturatedliquid feed
Feed Plate
R DR D + 1
y = x +xD
R D + 1
r
1.0
S t t d
Feed Plate
Distillation: ExampleNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
120/134
0.0 0.2 0.60.4 0.8 1.0 y = m o l e
f r a c
t i o n o f
E t O H i n
v a p o r
x = mole fraction of EtOH in liquid
0.2
0.4
0.8
EtOHH 2O
0.6
xa=0.84
Operating Line
If feed xF = 0.18Cold Feed Saturated
Liquid Vapor &Liquid If Saturatedliquid feed
If Cold feed
If Vapor &liquid feed
Vapor
If Vapor feed
o r1.0 L
D + Ly = x +D x D
D + L
Distillation: DiscussionNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
121/134
0.0 0.2 0.60.4 0.8 1.0 y = m o l e
f r a c t
i o n o f
E t O H i n v a p o
x = mole fraction of EtOH in liquid
0.2
0.4
0.8
EtOHH 2O
0.6
Operating Line
or
R DR D + 1
y = x +xD
R D + 1
Maximum R D ?
Minimum R D ?
Fractionating Column:Plate Column
D, x Dg
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
122/134
FractionatingColumn
EtOH-H 2OMixture
F, x F
B, x B
S t r i p p i n
g
R e c t i f y i n g
Plate Efficiency:
Fractionating Column:
Plate Column
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
123/134
Plate Efficiency:
Single plate efficiencyLocal efficiency
Overall efficiency
Actual Plate # =Theoretical Plate #
Plate Efficiency
50 60 %
Fractionating Column:Packed Column
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
124/134
Fractionating Column: Packs
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
125/134
Ballast Rings Cross Rings
Ball-Shaped PacksSaddles
NC STATE UNIVERSITY BAE 590G 2007
Fractionating Column: Packs
-
8/10/2019 Bioetanol generalitati ppt.pdf
126/134
Ballast Rings
Size: Diameter x Height: 1 x 1 inch
Specific Surface Area: 108 m 2 /m 3
Porosity: 86%
NC STATE UNIVERSITY BAE 590G 2007
Fractionating Column: Packed Column
-
8/10/2019 Bioetanol generalitati ppt.pdf
127/134
Equivalent Height of a Theoretical Plate
Total Height of Packs = EHTP x Theoretical Plate #
Dehydration
Ethanol concentration in fermentation beer: 10-20%
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
128/134
Fuel ethanol: > 99%
Distillation: Ethanol: 10-20% < 93%
Dehydration: Ethanol: < 93% > 99%
Dehydration
Molecular Sieves
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
129/134
Dehydration
Molecular Sieves9
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
130/134
Pore diameter: ~ 0.3 nm or 0.3 x 10 -9 m
Water molecular diameter: ~ 0.28 nm
EtOH molecular diameter: ~ 0.4 nm
Water Adsorption: 0.3 MPa
Molecular Sieve Recovery - Water Adsorption:Vacuum 50 kPa
By-Products
Starch-rich biomass:
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
131/134
Chemical composition:
Water Starch Proteins Fat Fiber Minerals% % % % % %
Corn 7-16 65-70 8-10 3-5 1-1.5 1.5-2
Potato 68-85 9-25 1-3.5 0.5-1.8
By-Products
Cellulose-rich biomass:
NC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
132/134
Cellulose Hemicellulose Lignin
Hardwood stems 40 - 55% 24 - 40% 18 - 25%
Softwood stems 45 - 50% 25 - 35% 25 - 35%
Switchgrass 45% 31% 12 - 20%Costal Bermuda grass 35% 22% 9 - 20%
Corn stover 39% 22% 21%
Wheat straw 30% 50% 15%
Corn-to-Ethanol ProcessNC STATE UNIVERSITY BAE 590G 2007
-
8/10/2019 Bioetanol generalitati ppt.pdf
133/134
Lignocellulosic BiomassNC STATE UNIVERSITY BAE 590G 2007
CelluloseHydrolysis
HexoseFermentation
Ethanol
-
8/10/2019 Bioetanol generalitati ppt.pdf
134/134
FermentationEthanolHemicellulose
PretreatmentHexoseHydrolysis
Pentose F e r m
e n t a t i o n
LigninDirect Combustion
HeatGasification
Syn gas (CO, H 2, CO 2, CH 4)