Process design of extraction of bioproducts with ionic liquids Martin

Process design of extraction of bioproducts with ionic liquids
Martin Stoffers, Andrzej Górak
Martin Stoffers
project started 01.06.09
Laboratory of Fluid Separations
Separations,
Department of Biochemical and Chemical Engineering, TU Dortmund
martin.stoffers@bci.tu-dortmund.de
Introduction
Acetone-Butanol-Ethanol-(ABE)-fermentation is getting more and more interesting for the production of alcohols, but efficient
purification technology of fermentation broth is still a bottleneck.
M i drawbacks:
Main
d
b k
toxicity
i i off butanol
b
l towards
d the
h microorganisms
i
i
resulting
l i in
i a limited
li i d productivity
d i i
high purification costs due to energy-intensive distillation step
Extraction with ionic liquids (ILs) for bioalcohol recovery is an interesting but very challenging option:
Possibility of in-situ liquid-liquid-extraction in order to avoid product inhibition
Commonly used organic extraction solvents are often flammable, hazardous or toxic
Objectives:
Design of a downstream processing method for biobutanol recovery from fermentation broth while certain
class of ionic liquids is used as extraction solvent
Experimental investigation of the extraction step in lab
lab-scale
scale
Modelling and simulation of the extraction step and investigation of different process concepts
Results
Experimental setup
Liquid-liquid extraction experiments are
conducted
in
agitated
and
tempered glass vessels. Distribution
coefficient
ffi i
and
d selectivity
l i i are indicators
i di
f
for
the quality of the butanol extraction. These
data are useful for the modelling of the
extraction process
Mass fraction :
wi =
mi
m tot
IL,eq
Di =
Distribution coefficient :
wi
aq,eq
wi
IL
Selectivity :
Si, j =
Di
Dj
wi
aq
=
wi
IL-phase
IL
wj
aq
wj
aqueous phase
with components : i, j
ionic liquid, aqueous phases : IL, aq
Analytics
The
h aqueous phase
h
is analysed
l d by
b High
h Performance
f
Liquid
d
Chromatography (HPLC). The ionic liquid phase is analysed by
Karl-Fischer titration. The calculation of the distribution
coefficient and selectivity is made with the help of HPLC-, KarlFischer results and weighted samples.
0,008
Butanol
Butyric acid
Acetone
Acetic acid
0,006
wiaq,eq [-]
Investigation of extraction time
I former
In
f
studies
di extraction
i
time
i
was set to 24 h to ensure that
h phase
h
equilibrium is reached. Concentrations between 0 and 120 min extraction time
are analysed. No significant change in four concentrations in the first hour could
be observed. Thus, extraction time is reduced from 24 to 1 h
0,004
0,002
0
0
Acknowledgements
The support of Merck KGaA is highly acknowledged.
CLIB-Graduate Cluster Industrial Biotechnology: Project Presentation.
30
60
90
Extraction
E
t
ti time
ti
[min]
[ i ]
120