Recovery of Citric Acid from Fermentation Broth Using Simulated Moving Bed Technology

187 Pages·2009·1.96 MB·English

Friedrich-Alexander-Universität Erlangen-Nürnberg
Lehrstuhl für Thermische Verfahrenstechnik

Recovery of Citric Acid from Fermentation Broth
Using Simulated Moving Bed Technology
-
Reinigung von Zitronensäure aus Fermentationslösung
durch kontinuierliche Chromatographie

Der Technischen Fakultät der Unveriversität Erlangen-Nürnberg
vorgelegt zur Erlangung des Grades

DOKTOR-INGENIEUR

vorgelegt von
Dipl.-Ing. Jinglan Wu
aus Jiangsu, China

Erlangen – 2009
Als Dissertation genehmigt von
der Technischen Fakultät der Universität Erlangen-Nürnberg

Tag der Einreichung: 09.11.2009
Tag der Promotion: 21.12.2009
Dekan: Prof. Dr.-Ing. R. German
Vorsitzender: Prof. Dr. W. Schwieger
1. Berichterstatter: Prof. Dr.-Ing. W. Arlt
2. Betichterstatter: Prof. Dr. R. Buchholz
Weiteres prüfungsberechtigtes Mitglied: Prof. Dr. C. Kryschi
Acknowledgments i
Acknowledgments
This work was carried out at the Lehrstuhl für Thermische Verfahrenstechnik, Friedrich-
Alexander-Universtät Erlangen-Nürnberg, during the years 2005-2009.
First of all, I would like to warmly thank my Doktorvater, Prof. Wolfgang Arlt for
giving me the opportunity for this work, for his optimism and generosity.
I would also like to thank my Chinese professor, Prof. Qijun Peng for the financial aid
to my work and for the support, especially for all the experiments performed in Jiangnan
University, Wuxi, China.
I own a lot of debts to my supervisor Dr. Mirjana Minceva. Without her support and
help, I can hardly finish the work. Also to my previous supervisor, Dr. Dirk-Uwe
Astrath, who is like my older brother and takes care of me since I was first here in
Germany.
I would like to thank Dr. Liudmila Mokrushina and her husband, Dr. Vladimir
Mokrushin, with whom I feel like with my family.
I am also grateful to my kind colleagues and the international entertainment group at
FAU Erlangen-Nürnberg during my stay in Germany. I would like to thank Dr. Stefanie
Herzog, Dr. Jörn Rolker and Dr. Oliver Spuhl for their friendliness and sympathy. I
appreciate my roommate Mr. Florian Lottes for the useful discussions. I also wish to
thank all other staff and colleagues, who are not mentioned here. I will never forget the
international entertainment group from India, Korea and South American, who treated
me bier-drink, shared laughter and foods with me.
I would like to thank all my Chinese friends, especially Wei Wei, Jin Geng and Tao
Tang for their emotional support and help to go through the hardest time with me during
my work. They are always there comforting me when I feel depressed.
I can not finish without saying how grateful to my parents for their patient and
understanding

Table of Contents iii
Table of Contents
Acknowledgments........................................................................................................................................i
Table of Contents.......................................................................................................................................iii
Nomenclature.............................................................................................................................................vi
Abbreviations.............................................................................................................................................vi
List of Figure Captions...............................................................................................................................x
Abstract.....................................................................................................................................................xv
Kurzfassung.............................................................................................................................................xvi
1 Motivation, objectives and outline....................................................................................................1
1.1 Properties and usage of citric acid............................................................................................1
1.2 Downstream purification processes for recovery of citric acid from the fermentation broth...2
1.2.1 Conventional citric acid recovery processes.........................................................................3
1.2.2 Recovery of citric acid based on chromatography technology.............................................8
1.2.3 Novel citric acid purification process based on Simulated Moving Bed technology............9
1.3 Objectives and dissertation outline.........................................................................................12
2 Introduction to Simulated Moving Bed technology......................................................................16
2.1 Separation principle of liquid chromatography......................................................................16
2.2 Basics of liquid chromatography.............................................................................................16
2.2.1 Column porosities definitions.............................................................................................16
2.2.2 Chromatogram and derived parameters..............................................................................17
2.2.2.1 Retention time...........................................................................................................18
2.2.2.2 Capacity factor and separation factor........................................................................19
2.2.2.3 Peak width.................................................................................................................19
2.2.2.4 Efficiency of chromatographic separations...............................................................20
2.2.2.5 Resolution.................................................................................................................20
2.3 Adsorption equilibrium............................................................................................................20
2.3.1 Definition of isotherms.......................................................................................................20
2.3.2 Models of adsorption isotherms..........................................................................................21
2.3.2.1 Linear isotherm.........................................................................................................21
2.3.2.2 Langmuir isotherm....................................................................................................21
2.3.2.3 Modified Langmuir isotherm....................................................................................22
2.3.3 Influence of adsorption isotherm type on the peak shape...................................................22
2.4 Hydrodynamics and kinetics....................................................................................................24
2.4.1 Axial dispersion..................................................................................................................24
2.4.2 Mass transfer resistance......................................................................................................24
2.5 Modelling of chromatographic separation..............................................................................25
2.5.1 Transport dispersive model.................................................................................................27
2.5.2 The lumped rate model with a solid film linear driving force approach.............................27
2.5.3 Pore diffusion model...........................................................................................................28
2.5.4 Initial and boundary conditions of the models....................................................................29
2.6 Determination of model parameters........................................................................................29
2.6.1 Column and particle porosities...........................................................................................29
2.6.2 Axial dispersion..................................................................................................................31
2.6.3 Adsorption isotherms..........................................................................................................32
2.6.4 Kinetic parameters..............................................................................................................34
iv Table of Contents
2.7 Operating modes.....................................................................................................................34
2.8 Simulated moving bed..............................................................................................................35
2.8.1 Principle of SMB technology.............................................................................................35
2.8.2 Advantages and disadvantages of SMB technology...........................................................36
2.8.3 Modelling of SMB operation..............................................................................................38
2.8.3.1 TMB model strategy.................................................................................................38
2.8.3.2 Real SMB modelling strategy...................................................................................39
2.8.4 SMB design methodologies................................................................................................40
2.8.4.1 Separation triangle methodology...............................................................................40
2.8.4.2 Separation volume design methodology...................................................................43
2.8.5 SMB optimization...............................................................................................................45
2.8.5.1 Objective function.....................................................................................................45
2.8.5.2 Optimization variables..............................................................................................46
2.8.5.3 Optimization strategy................................................................................................46
2.8.5.4 Optimization algorithm.............................................................................................47
3 Modelling of the chromatographic system.....................................................................................49
3.1 Experiments.............................................................................................................................49
3.1.1 Materials.............................................................................................................................49
3.1.1.1 Chemicals..................................................................................................................49
3.1.2 Equipment...........................................................................................................................51
3.1.2.1 Semi-preparative chromatographic system...............................................................51
3.1.2.2 Preparative chromatographic system.........................................................................51
3.1.3 Analytical methods.............................................................................................................51
3.1.4 Determination of model parameters....................................................................................52
3.1.4.1 Column porosity and axial dispersion coefficient.....................................................52
3.1.4.2 Adsorption isotherms................................................................................................53
3.1.4.3 Mass transfer parameters...........................................................................................53
3.1.5 Elution profiles...................................................................................................................55
3.2 Numerical method...................................................................................................................56
3.3 Results and discussions...........................................................................................................57
3.3.1 Chromatographic model parameters...................................................................................57
3.3.1.1 Column porosity and axial dispersion.......................................................................57
3.3.1.2 Adsorption isotherms................................................................................................58
3.3.2 Single column model selection...........................................................................................59
3.3.3 TDM model validation in a preparative chromatographic column.....................................62
3.3.3.1 Single component elution profiles.............................................................................62
3.3.3.2 Fermentation broth elution profiles...........................................................................64
4 Modelling of an existing pilot-scale SMB unit...............................................................................69
4.1 An existing pilot-scale SMB unit.............................................................................................69
4.2 Preliminary design of an existing pilot-scale SMB unit operating conditions........................70
4.2.1 TMB and SMB models.......................................................................................................70
4.2.2 TMB and SMB unit separation performances....................................................................73
4.2.3 Preliminary design of the SMB operating conditions based on separation triangle
methodology......................................................................................................................................74
4.3 SMB experiments.....................................................................................................................76
4.4 SMB and TMB model verification...........................................................................................77
4.4.1 CSS concentration profiles and concentration histories......................................................77
4.4.2 Sensitivity Analysis............................................................................................................87
4.4.2.1 Influence of the column numbers on the CSS concentration profiles.......................87
4.4.2.2 Influence of the adsorption capacity on the CSS concentration profiles...................89
4.4.2.3 Influence of the pump flow rates on the CSS concentration profiles........................90
4.4.3 Separation performances....................................................................................................92
5 Design of the existing pilot-scale SMB system...............................................................................96
Table of Contents v
5.1 Influences of operating conditions on the separation regions and performances...................96
5.1.1 Influences of m on the separation regions and performances..........................................97
1
5.1.2 Influence of m on the SMB performances......................................................................99
4
5.1.3 Influence of t* on the SMB performances.....................................................................100
5.1.4 Influence of the SMB configurations on its performances...............................................102
5.2 New design of the exiting SMB unit operating conditions.....................................................104
5.2.1 New SMB separation region.............................................................................................104
5.2.2 SMB unit operations.........................................................................................................104
5.2.3 Analysis of the final CA product......................................................................................109
6 Optimization of the pilot-scale SMB unit.....................................................................................111
6.1 Direct cyclic steady state modelling strategy........................................................................111
6.1.1 Direct determination of CSS.............................................................................................111
6.1.2 Comparison of steady state TMB, transient SMB and direct CSS prediction models......115
6.2 Optimization of the existing pilot-scale SMB unit.................................................................118
6.2.1 Optimization of the number of SMB columns and SMB unit configurations...................118
6.2.2 Optimization of the operating conditions for the existing SMB unit................................125
6.2.3 Calculation of the optimal operating conditions...............................................................125
6.2.3.1 Experimental validation of the optimized SMB operating conditions....................136
6.3 Complete optimal design of a new SMB unit.........................................................................143
6.3.1 Influence of column lengths on the SMB separation performances.................................144
6.3.2 Optimization procedure towards complete SMB unit design...........................................146
6.3.3 Pilot scale SMB unit scaling up........................................................................................150
7 Conclusions and some suggestions for the future work..............................................................155
7.1 Conclusions...........................................................................................................................155
7.2 Perspective............................................................................................................................158
Reference List.........................................................................................................................................160
vi Nomenclature

Nomenclature
Abbreviations
BDNSOL Block Decomposition Nonlinear SOLver
CA Citric Acid
CSS Cyclic Steady State
CVP control vector parameterization
EDM Equilibrium Dispersive Model
GA Genetic Algorithm
Glu glucose
gPROMS general PROcess Modeling System
HETP Height Equivalent to a Theoretical Plate
HPLC High Performance Liquid Chromatography
IPOPT Interior Point Optimizer
LDF lumped rate model with a solid film linear driving force model
MB mass balance
MW molecular weight
NSGA Non-dominated Sorting Genetic Algorithm
OCFEM Orthogonal Collocation on Finite Elements Method
PDM Pore Diffusion Model
PVP tertiary poly (4-vinylpyridine) resin
RCS Readily Carbonizable Substances
SMB Simulated Moving Bed
SS single shooting
SWD standing wave design
TDM Transport Dispersive Model
TMB True Moving Bed
Greek Letters
α separation factor (selectivity) [-]
a constant which accounts for solute-solvent interactions
α [-]
A (2.26 for water)
ε total porosity [-]
t
ε interstitial porosity [-]
ε particle porosity [-]
p
γ external tortuosity [-]
λ characterization factor of the packing [-]
Nomenclature vii
µ dynamic viscosity [Pa·s]
µ first absolute moment [min]
t
ρ density of the solvent [g/ml]
s
σ2 Variance of the peak [min2]
t
τ dimensionless time [-]
ω peak width of species i [min]
i
Latin Letters
A strong adsorbed species [-]
A cross section area of the chromatographic column [cm2]
c
a Langmuir isotherm parameters of species i [-]
i
B less strong adsorbed species [-]
b Langmuir isotherm parameters of species i [l/g]
i
C dimensionless concentration [-]
c concentration of solute i in the fluid phase [g/l]
i
cin inlet concentration of solute i [g/l]
i
c average concentration of solute i in extract stream [g/l]
X,i
c average concentration of solute i in raffinate stream [g/l]
R,i
c average concentration in the pores [g/l]
p,i
c concentration of solute i in feed stream [g/l]
F,i
c concentration of solute i in raffinate stream [g/l]
R,i
c concentration of solute i in extract stream [g/l]
X,i
D axial dispersion coefficient [cm2/min]
ax
D molecular diffusivity [cm2/min]
m
D pore diffusion coefficient [cm2/min]
pore
d particle diameter [µm]
p
EC eluent consumption l/kg
erf (x) error function [-]
erfc(x) complementary error function [-]
viii Nomenclature
H Henry constant of species i in the linear isotherm model [-]
i
modified Langmuir isotherm model parameter of species
h [-]
i i
k' capacity factor of species i [-]
i
k internal mass transfer resistance of species i [min-1]
int,i
k external mass transfer resistance of species i [min-1]
film,i
k effective mass transfer coefficient of species i [min-1]
eff,i
lumped mass transfer coefficient in the solid phase of
k [min-1]
eff,s species i
L column length [cm]
c
L total column length [cm]
c,tot
M molecular weight of the solvent [g/mol]
s
m ratio of net fluid flow to net solid flow in each section [-]
j
N number of theoretical plates of species i [-]
i
N number of column [-]
c
Pe Peclet number [-]
PD product dilution [%]
PR productivity [kg/(l•min)]
PUX purity in the extract stream [%]
q loading, concentration in the stationary phase [g/l]
i
overall solid loading, concentration in the stationary
q* [g/l]
i phase
q* hypothetical solid loading, concentration in the stationary [g/l]
eq phase
q adsorbent saturation capacity [g/l]
sat
Q eluent flow rate [ml/min]
El
Q feed flow rate [ml/min]
F
Q raffinate flow rate [ml/min]
R
Q volumetric flow rate of solid phase [ml/min]
s
Q extract flow rate [ml/min]
X
QTMB TMB internal volumetric fluid flow rate in each section [ml/min]
j