BioSep - Membrane Technology and Research, Inc.

BioSep™: A New Ethanol Recovery
Technology for Small Scale Rural
Production of Ethanol from Biomass
Yu (Ivy) Huang, Ph.D.
Membrane Technology & Research, Inc.
1360 Willow Road, Suite 103
Menlo Park, California
&
Leland M. Vane, Ph.D.
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio
AICHE
San Francisco, California
November 2006
1
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 2010
20 - 30% replacement of oil by 2030
China
Launched a program to use ethanol as a fuel
2
How much ethanol can we produce?
Current:
¾Oil consumption: 873 MM gal/day, 58% import
¾Ethanol production: 12 MM gal/day
Forecast for 2025:
¾Oil consumption from import: 870 MM gal/day
¾The President’s goal: replace 75% import from Mideast − 100 MM gal/day
40,000
35,000
30,000
Total annual
ethanol production
(MM gal/y)
25,000
20,000
15,000
10,000
5,000
0
1970
1980
1990
2000
2010
2020
2030
3
Conventional Bioethanol Process
MOL
SIEVE
Ethanol
Biomaterial
FERMENTATION
DISTILLATION
COLUMN
Water
4
Ethanol from Biomass
Two competing driving forces:
¾ Ethanol concentration/purification by distillation/molecular sieve
is only economical at > 40-50 MM gal/year
Æ driver for central production
¾ Transport of biomass over long distances is costly and energy
inefficient
Æ driver for distributed production in rural areas
(with added benefits for rural economies)
Can this problem be solved?
The solution is membranes (of course).
5
MTR BioSep Process
MOL
SIEVE
Biomass
Ethanol
DISTILLATION
FERMENTATION
Water
Water
PERVAPORATION
(dehydration)
Ethanol
FERMENTATION
PERVAPORATION
(ethanol concentration)
DEPHLEGMATION
6
Applications of BioSep Process
¾ 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
¾ Replace molecular sieve in conventional corn to ethanol
plant
¾ Replace distillation in conventional corn to ethanol plant
7
What is pervaporation?
Pervaporation = Permeation + Evaporation
To vacuum system
permeate
βmem
βevap
feed
Separation factor
Saturated vapor
Liquid feed
β = β evap ⋅ β mem
residue
y1 /(1 − y1 )
=
x1 /(1 − x1 )
Not limited by thermodynamic vapor-liquid equilibrium (VLE)
8
Pervaporation Applications
¾ Dehydration of organic solvents
‹
‹
‹
‹
Primarily dehydration of ethanol and iso-propanol
First commercial plant in the world was put into operation
in Brazil in 1984.
Commercial application of inorganic membranes
Needs improvements to be competitive with molecular
sieves in large scale applications
¾ Removal and recovery of organic solvents from water
‹
Commercially successful applications are hard to find
9
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
10
Fractional condensation (dephlegmation)
improves separation
Vapor enters at the bottom
Vapor is partially condensed
at the top
Condensate trickles down,
creates a counter-current effect
Achieves 4 to 6 theoretical
stages of separation
11
Significant increase in
separation performance ….
12
MTR BioSep Process
2
0.5 wt% ethanol
to recycle or waste
4
Ethanolpermeable
pervaporation
membrane
1
Filtered biomass feed
(10 wt% ethanol)
90 - 95 wt%
ethanol
30-40 wt%
3 ethanol
vapor
7
Waterpermeable
pervaporation
membrane
6
99+ wt%
ethanol
Dephlegmator
20 wt%
5 ethanol
vapor
5 wt% ethanol recycle
Pervaporation-dephlegmation
Dehydration
13
Ethanol Permeable Membranes
5 MM gal/year plant, feed ethanol concentration = 10wt%
30
15
25
20
10
Energy consumption
for distillation
Total
membrane area
15
2
(Thousand m )
5
Total energy
consumption
(million Btu/hr)
10
5
0
0
10
20
30
40
50
0
EtOH/H O separation factor, β
2
Solution: zeolite mixed-matrix membrane
14
Mixed-matrix Membranes
Effects of zeolite loadings
5
30
4
20
3
Ethanol/water
separation factor,
β
Ethanol/water
selectivity, β
2
mem
10
1
0
0
20
40
60
80
0
100
Zeolite loading (wt%)
15
Ethanol Dehydration Membranes
100
MTR-2
Celfa
80
60
Permeate water
concentration
(wt%)
40
MTR-2
20
o
Temperature = 100 C
0
0
20
40
60
80
100
Feed water concentration (wt%)
16
Package membranes into spiral-wound modules
17
Conclusions
• Pervaporation offers alternative to distillation for ethanol
recovery
‹ Higher selectivity membranes will yield energy savings
‹ Membranes scale down better than distillation
• Pervaporation offers alternative to molecular sieves for water
removal
‹ Chemical and thermal stable membranes developed
‹ Systems commercially available
• Synergies achievable through use of pervaporation for both
ethanol recovery and dehydration
‹ Combined with dephlegmation condensation
18
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
19
Questions?
2020
Liquid Separation Group
MTR Confidential