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Martin Miltner, Florian Kirchbacher, Antonia ROM, Walter WUKOVITS, Michael HARASEK, Anton FRIEDL
Technische Universität Wien, Vienna, Austria
5th PVVPMD Conference, Torun, 20-23 June 2017
w w w . w a s t e 2 f u e l s . e u
Grant agreement no: 654623
H 2 0 2 0 – L C E - 1 1 - 2 0 1 5
Solvent Recovery From ABE Solutions Applying Pervaporation Under Realistic Process Conditions
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Objectives
WASTE2FUELS aims to:
• Develop next generation biofuels technologies
• Contribute to a decentralized energy production
• Produce bio-butanol as sustainable alternative fuel
• Enlarge the current biomass feedstock basis
• Convert unavoidable agrofood waste streams (AFW)
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Agenda
Butanol and ABE fermentation
Energy demand for separation and dehydration
Composition of typical ABE fermentation broth
Experimental procedure
Analysis of influencing factors on pervaporation
• Temperature
• Glucose content
• Salt content
Comparison of membrane materials
Summary and Outlook
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ABE Fermentation
Pro Butanol Contra Butanol
High energy content Low productivity
Low water absorption Product inhibition at 20g/l
Low vapour pressure
Good blending ability
Low corrosivity
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Solvent recovery from fermentation
1. StageAcetogenic
2. StageSolventogenic Downstream to distillation
In-situ product recovery
Inhibition level
Co
nce
ntr
atio
n
Stages of fermentation and product recovery
Mas
s fr
acti
on
of
Bu
tan
oli
n v
apo
ur
Mass fraction of Butanol in liquid
VLE Butanol/Water:
non-ideal behaviour
Miscibility gap Butanol/Water
High fugacity at low concentrations
Ideal for thermal separation process
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Energy demand
Energy content Butanol: 35 MJ/kg
Energy demand for separation and dehydration (BuOH 2 % 98 %): Conventional Rectification: 79,5 MJ/kg Gas Stripping/Rectification: 14-31 MJ/kg Extraction/Rectification: 4 – 6 MJ/kg Pervaporation/Rectification: 4 – 8 MJ/kg
Source: Rom, Miltner, Wukovits, Friedl; Chemical Engineering and Processing 104 (2016) 201-211
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Composition of fermentation broth
ComponentConcentration
[g/l]
Butanol 8 – 15
Acetone 4 - 8
Ethanol 1 - 2
Residual sugar up to 50 (depending)
Acetic acid 0.85
Propionic acid 1.76
Butyric acid 0.44
Sources:Universita degli studi di Napoli Federico II, Italy; University of Natural Resources and Life Sciences, Austria
ComponentConcentration
[g/l]
NH4Cl 2.0
K2HPO4 0.25
KH2PO4 0.25
MgSO4 0.2
FeSO4 0.01
MnSO4 0.01
Typical composition of real ABE fermentate from model substrates
Organic compounds strongly depending on fermentation design and microbial strain
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Experimental setup
Cross-flow pervaporation cell
Flat sheet membrane (0.0144m²)
POMS membrane from HZG
Hollow fiber modules possible
Feed: 100l/h flowrate, 25 - 70°C temperature
10mbar(a) permeate pressure
Liquid nitrogen condensation
Composition analysis by GC-FID
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Temperature dependence
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Temperature dependence
Transmembrane fluxes significantly higher at elevated temperatures
Enrichment similar at all analysed temperatures (uncertainties)
Permeance of BuOH is decreasing, selectivity stays constant
Product recovery at fermentation temperature is favoured
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Glucose dependence
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Glucose dependence
No influence of glucose content at reasonable levels (0 – 50g/l)
Slight decrease of permeances at very high glucose content (200g/l):
BuOH: -15% AcO: -23% EtOH: -17% Water: -16%
No fouling detected
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Salt dependence
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Salt dependence
No influence of NH4Cl content at levels expected in fermentation broth
No fouling and scaling detected
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Permeances
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Selectivities
BuOH
AcO
EtOH
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Performance indicators
Membrane Type
Separation factor i/j[-]
PSIi[kg/m².h]
BuOH/W AcO/W EtOH/W BuOH AcO EtOH
POMS(HZG)
33.0(±5.6)
51.2(±9.3)
9.0(±1.4)
2.83(±1.6)
2.76(±1.3)
0.04(±0.02)
PDMS(Sulzer)
29.0(±4.3)
53.3(±8.5)
9.2(±1.1)
3.31(±1.3)
4.59(±1.9)
0.06(±0.02)
Membrane Type
Permeancei[kmol/m².h.bar]
Selectivity P i/j[-]
BuOH AcO EtOH W BuOH/W AcO/W EtOH/W
POMS(HZG)
0.67(±0.19)
0.26(±0.05)
0.21(±0.03)
0.27(±0.06)
2.46(±0.50)
0.99(±0.21)
0.79(±0.15)
PDMS(Sulzer)
1.04(±0.29)
0.51(±0.15)
0.40(±0.07)
0.46(±0.07)
2.37(±1.17)
1.16(±0.65)
0.89(±0.31)
PDMS analysis has been performed under the Austrian research project KASAV, grant No 838708
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Summary
Solvent enrichment in the permeate:
Taking advantage of phase separation behavior (organic phase with 80% BuOH, aqueous phase with 8%)
Reduction of energy demand for extraction & dehydration
Influence of secondary components in fermentation broth
Feed:BuOH 1.5wt%AcO 0.75wt%EtOH 0.25wt%Water 97.5wt%
Permeate:BuOH 31.5wt%AcO 24.0wt%EtOH 1.5wt%Water 43.0wt%
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Outlook
Resistance to acidic fermentation broth conditions
Influence of organic acids (acetic, propionic, butyric)
Performance with real fermentation broth
Further comparison to other membrane materials:
• Flat sheet PDMS and POMS from different vendors
• Hollow fiber module (interesting for upscaling)
Process simulation:
• Development and parameterization of rigorous model
• Validation of model (chemometrics)
• Simulation of different downstream process options
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beyond the advanced precision agriculture/farming systems.
Partners
www.waste2fuels.euThis project has received funding from the European Union’s Horizon 2020 researchand innovation programme under grant agreement No 654623
Contact: [email protected], [email protected]
Thanks for your attention!
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Formula & Definitions
Driving force - Partial pressure difference
Selectivity
Transmembrane component flux
Separation factor
Pervaporation separation index
𝑁𝑖 = Π𝑖 ∗ 𝑝𝑖𝑠𝑎𝑡𝛾𝑖𝑥𝑖 − 𝑝𝑝𝑒𝑟𝑚𝑦𝑖
𝛼𝑖𝑗 =Π𝑖Π𝑗
𝐽𝑖 =𝑚𝑖𝐴𝑡
𝛽 =𝑤𝑓𝑖𝑤𝑝𝑗
𝑤𝑓𝑗𝑤𝑝𝑖
𝐴 𝑚𝑒𝑚𝑏𝑟𝑎𝑛𝑒 𝑎𝑟𝑒𝑎 [𝑚²]
𝑡 𝑡𝑖𝑚𝑒 [ℎ]
𝑤𝑓 , 𝑤𝑝 𝑤𝑒𝑖𝑔ℎ𝑡 𝑓𝑟𝑎𝑐𝑡𝑖𝑜𝑛 𝑖𝑛 𝑓𝑒𝑒𝑑 𝑎𝑛𝑑 𝑝𝑒𝑟𝑚𝑒𝑎𝑡 [−]
𝐽𝑖 𝑡𝑟𝑎𝑛𝑠𝑚𝑒𝑚𝑏𝑟𝑎𝑛𝑒 𝑓𝑙𝑢𝑥 𝑘𝑔 𝑚2ℎ
𝑚𝑖 𝑚𝑎𝑠𝑠 𝑜𝑓 𝑖 [𝑘𝑔]
𝑝𝑖𝑠𝑎𝑡 𝑠𝑎𝑡𝑢𝑟𝑎𝑡𝑖𝑜𝑛 𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒 [𝑏𝑎𝑟]
𝛾𝑖 𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦 𝑐𝑜𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡 [−]
𝑥𝑖 , 𝑦𝑖 𝑚𝑜𝑙𝑒 𝑓𝑟𝑎𝑐𝑡𝑖𝑜𝑛 𝑖𝑛 𝑙/𝑣 𝑝ℎ𝑎𝑠𝑒 [−]
𝑁𝑖 𝑡𝑟𝑎𝑛𝑠𝑚𝑒𝑚𝑏𝑟𝑎𝑛𝑒 𝑓𝑙𝑢𝑥 𝑘𝑚𝑜𝑙 𝑚2ℎ
Π𝑖 𝑃𝑒𝑟𝑚𝑒𝑎𝑛𝑐𝑒 [𝑘𝑚𝑜𝑙/𝑚2ℎ𝑏𝑎𝑟]
𝑃𝑆𝐼𝑖 = 𝐽𝑖 ∗ 𝛼𝑖𝑗 − 1