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Yu (Ivy) Huang, Ph.D.Membrane Technology & Research, Inc.
1360 Willow Road, Suite 103Menlo Park, California
&
Leland M. Vane, Ph.D.Office of Research and Development
U.S. Environmental Protection AgencyCincinnati, Ohio
AICHESan Francisco, California
November 2006
BioSep™: A New Ethanol Recovery Technology for Small Scale Rural
Production of Ethanol from Biomass
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Ethanol production is growing globally
Brazil > 50% sugar cane crop 40% non-diesel fuel
USA currently, 15% corn crop 2% non-diesel fuel> 1/3 oil displacement by 2025
EU 6% biofuel by 201020 - 30% replacement of oil by 2030
China Launched a program to use ethanol as a fuel
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How much ethanol can we produce?
Oil consumption: 873 MM gal/day, 58% import Ethanol production: 12 MM gal/day
Current:
Oil consumption from import: 870 MM gal/day The President’s goal: replace 75% import from Mideast − 100 MM gal/day
Forecast for 2025:
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5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
1970 1980 1990 2000 2010 2020 2030
Total annual ethanol production
(MM gal/y)
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FERMENTATION DISTILLATIONCOLUMN
MOLSIEVE Ethanol
Water
Biomaterial
Conventional Bioethanol Process
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Two competing driving forces:Ethanol concentration/purification by distillation/molecular sieve is only economical at > 40-50 MM gal/year
driver for central productionTransport of biomass over long distances is costly and energy inefficient
driver for distributed production in rural areas(with added benefits for rural economies)
Can this problem be solved?The solution is membranes (of course).
Ethanol from Biomass
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MTR BioSep Process
FERMENTATION
PERVAPORATION(ethanol concentration)
DEPHLEGMATION
Ethanol
Water
FERMENTATION DISTILLATION
MOLSIEVE
Ethanol
Water
Biomass
PERVAPORATION(dehydration)
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Applications of BioSep Process
Small biomass waste streams generated in the production of-- beer, wine, and juice-- cane and beet sugar-- potatoes, yams, and other root crops-- cheese, soft drinks, confectionery and packaged foods
Replace molecular sieve in conventional corn to ethanol plant
Replace distillation in conventional corn to ethanol plant
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What is pervaporation?
Liquid feed
Saturated vapor
To vacuum systempermeate
βevap
βmem
)1/()1/(
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11
xxyy
memevap −−
=⋅= βββ
Pervaporation = Permeation + Evaporation
feed residue
Not limited by thermodynamic vapor-liquid equilibrium (VLE)
Separation factor
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Dehydration of organic solventsPrimarily dehydration of ethanol and iso-propanolFirst commercial plant in the world was put into operation in Brazil in 1984.Commercial application of inorganic membranesNeeds improvements to be competitive with molecular sieves in large scale applications
Removal and recovery of organic solvents from waterCommercially successful applications are hard to find
Pervaporation Applications
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Pervaporation using Ethanol-Permeable and Water-Permeable Membranes
Ethanol removal from 5-10 wt% ethanol/water mixture
Water removal from 90 wt% ethanol/water mixture
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Vapor enters at the bottom
Vapor is partially condensedat the top
Condensate trickles down,creates a counter-current effect
Achieves 4 to 6 theoreticalstages of separation
Fractional condensation (dephlegmation) improves separation
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Significant increase in separation performance ….
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Pervaporation-dephlegmation Dehydration
Filtered biomass feed(10 wt% ethanol)
30-40 wt% ethanol vapor 20 wt%
ethanol vapor
5 wt% ethanol recycle
0.5 wt% ethanol to recycle or waste
90 - 95 wt% ethanol
Dephlegmator
Water-permeable
pervaporationmembrane
Ethanol-permeable
pervaporationmembrane
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2
3
4
5
99+ wt% ethanol6
MTR BioSep Process
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Ethanol Permeable Membranes
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5
10
15
0
5
10
15
20
25
30
0 10 20 30 40 50
Total membrane area
(Thousand m2)
Total energy consumption
(million Btu/hr)
EtOH/H2O separation factor, β
Energy consumption for distillation
5 MM gal/year plant, feed ethanol concentration = 10wt%
Solution: zeolite mixed-matrix membrane
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0
10
20
30
0
1
2
3
4
5
0 20 40 60 80 100
Ethanol/waterselectivity, β
mem
Zeolite loading (wt%)
Ethanol/waterseparation factor,
β
Mixed-matrix Membranes
Effects of zeolite loadings
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Ethanol Dehydration Membranes
MTR-2
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20
40
60
80
100
0 20 40 60 80 100
Permeate water concentration
(wt%)
Feed water concentration (wt%)
MTR-2Celfa
Temperature = 100oC
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Package membranes into spiral-wound modules
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Conclusions
• Pervaporation offers alternative to distillation for ethanol recovery
Higher selectivity membranes will yield energy savingsMembranes scale down better than distillation
• Pervaporation offers alternative to molecular sieves for water removal
Chemical and thermal stable membranes developedSystems commercially available
• Synergies achievable through use of pervaporation for bothethanol recovery and dehydration
Combined with dephlegmation condensation
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Acknowledgments
• U.S. Department of Energy• U.S. Department of Agriculture• Jennifer Ly, Tiem Aldajani, Karl Amo of MTR• Vasudevan Namboodiri, Travis Bowen of EPA
20MTR Confidential
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Liquid Separation Group
Questions?Questions?