Experimental investigation on gas separation using porous membranes [Elektronische Ressource] / vorgelegt von Weiqi Zhang

Informations

• Publié par: technische_universitat_berlin
• Publié le: 01 janvier 2011
• Nombre de lectures: 16
• Langue: English
• Poids de l'ouvrage: 8 Mo

Extrait

Experimental Investigation on Gas Separation
Using Porous Membranes
vorgelegt von
Master-Ing.
Weiqi ZHANG
von der Fakultät III - Prozesswissenschaften
der Technischen Universität Berlin
zur Erlangung des akademischen Grades
Doktorin der Ingenieurwissenschaften
– Dr.-Ing. –
genehmigte Dissertation
Promotionsausschuss:
Vorsitzender: Prof. Dr.-Ing. Felix Ziegler
Berichter: Prof. Dr. Frank Behrendt
Berichter: Prof. Dr.-Ing. Bernd Hillemeier
Tag der wissenschaftlichen Aussprache: 03. December 2010
Berlin 2011
D 83Ich erkläre hiermit, dass ich die vorliegende Arbeit selbständig verfasst und keine an-
deren als die angegebenen Quellen und Hilfsmittel verwendet habe.
Berlin, den 03. December 2010Acknowledgment
I am deeply thankful to colleagues and advisors, who helped me complete for this
project, firstly to Univ.-Prof. Dr. Frank Behrendt, who gave me the opportunity to
do this Ph.D., made this work possible; Prof. Dr.-Ing. Bernd Hillemeier and Prof.
Dr.-Ing. Felix Ziegler, who took over the supervision of my thesis.
Maria Gaggl, who helped me with the practicalities of living in Germany, and even
shared with me her flat for two weeks when I first started my Ph.D.. Gregor Gluth,
for making all the membranes used in this project, but also for his patience. Dr.-
Ing. York Neubauer and Dr.-Ing. Nico Zobel, for their competence; if you encounter
any problems, either theoretical or experimental status, you can turn to them and
certainly get a reasonable answer. Horst Lochner and Uwe Röhr, who made membrane
cell and many other small parts patiently for me, and helped me with all sorts of
technicalities. Susanne Hoffmann who gave me lots of suggestions over operations with
gas chromatograph (GC). Fang He, Gregor Drenkelfort, Birgit Packeiser, Renhui sun,
etc., my special thanks also go to for their patience and advice.
I would also like to acknowledge the on going financial support provided by Federal
Ministry of Food, Agriculture and Consumer Protection (BMELV), Agency for Renew-
able Resources (FNR), and the scholarship from Women’s central office to finish my
thesis.
Last but not least, I would like to thank all the helpful persons that I have forgotten
to mention by name. This thesis could not have been written without the support of
my parents, my husband Jingqun Song and my friends.Contents
Abstract XIII
Nomenclature XV
1 Introduction 1
2 State of the Art 5
2.1 An introduction to gas separation using membranes . . . . . . . . . . . 5
2.2 Inorganic membranes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2.1 Dense inorganic membranes . . . . . . . . . . . . . . . . . . . . 7
2.2.2 Porous inorganic membranes . . . . . . . . . . . . . . . . . . . . 8
2.3 Porous cement membranes . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.4 Separation and process design . . . . . . . . . . . . . . . . . . . . . . . 10
2.4.1 Possible flow patterns . . . . . . . . . . . . . . . . . . . . . . . . 10
2.4.2 Number of stages . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.4.3 Known influence of operating parameters . . . . . . . . . . . . . 14
3 Experimental Setup 17
3.1 Flow chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.2 Experimental setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.3 Operating parameters and procedure . . . . . . . . . . . . . . . . . . . 26Contents VII
4 Summary of Equations 31
4.1 Basic assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.2 Gas equations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.2.1 The fundamental equations for ideal gases . . . . . . . . . . . . 32
4.2.2 Balances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.3 Equations for transport mechanisms through porous membranes . . . . 33
4.4 for the experimental setup . . . . . . . . . . . . . . . . . . . 35
4.4.1 LabVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
4.4.2 Soap film flowmeter . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.4.3 Mass flow controller . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.4.4 Gas chromatograph . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.5 Efficiency of gas separation through membrane . . . . . . . . . . . . . . 37
5 Experimental Results and Discussion 41
5.1 Controlling equipment and corresponding special procedures, calibration 41
5.1.1 Bubble flow-meter . . . . . . . . . . . . . . . . . . . . . . . . . 41
5.1.2 Data correction of mass flow controller . . . . . . . . . . . . . . 42
5.1.3 Calibration of gas chromatograph (GC) . . . . . . . . . . . . . 43
5.2 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
5.2.1 First set of experiments with Gaggl’s membranes . . . . . . . . 55
5.2.2 Second set of experiments with modified cell . . . . . . . . . . . 62
5.2.3 Third set of experiments with tubular membrane and cell . . . . 83
6 Summary and Outlook 91
6.1 Summary of results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
6.2 Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
6.3 Future work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Bibliography 97
Mitteilungen 107List of Figures
2.1 Schematic representation of membrane separation . . . . . . . . . . . . 6
2.2 Transport mechanisms in porous membranes [1] . . . . . . . . . . . . . 9
2.3 Schematics of possible flow patterns [2,3] . . . . . . . . . . . . . . . . . 10
2.4 Flow pattern in presence of sweep gas [2] . . . . . . . . . . . . . . . . . 11
2.5 Schemes of commercial two-stage separation [2,3] . . . . . . . . . . . . 12
2.6 Schemes of three-stage separation [2,3] . . . . . . . . . . . 13
2.7 Novel single-stage separation with recycling [2,3] . . . . . . . . . . . . . 13
3.1 Process schematic of gas separation . . . . . . . . . . . . . . . . . . . . 17
3.2 Process schematic of reference measurements . . . . . . . . . . . . . . . 18
3.3 Gas chromatographic system . . . . . . . . . . . . . . . . . . . . . . . . 22
3.4 Chromatogram of five-component gas . . . . . . . . . . . . . . . . . . . 23
3.5 LabVIEW controlling system . . . . . . . . . . . . . . . . . . . . . . . 25
4.1 Chromatograms of two-component gas and pure standard-gases . . . . 37
5.1 Flow rate of two-component gas at 2.4 bar . . . . . . . . . . . . . . . . 43
5.2 Flow rate of 2 % to 4 % . . . . . . . . . . . . . . . . . . . . . . . . . . 44
5.3 Flow rate of two-component gas at different pressures . . . . . . . . . . 45
5.4 GC measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
5.5 Base line of chromatogram . . . . . . . . . . . . . . . . . . . . . . . . . 46
5.6 Area of H in two-component gas measurements with different run times 472
5.7 Area of pure H measurements at different temperatures . . . . . . . . 482X List of Figures
5.8 GC measurements of different reference-flow rate . . . . . . . . . . . . . 50
5.9 N amount and flow rates in automatic injection . . . . . . . . . . . . . 512
5.10 Flow rate calculation of standard-gases . . . . . . . . . . . . . . . . . . 52
5.11 Pure H peak area for calibration of 2M measurement . . . . . . . . . . 532
5.12 Calibration curve for H of 2M measurement . . . . . . . . . . . . . . . 542
5.13 Schematic of the first idea . . . . . . . . . . . . . . . . . . . . . . . . . 55
5.14 Schematic of the first membrane cell . . . . . . . . . . . . . . . . . . . 56
5.15 The first membrane cell and holders . . . . . . . . . . . . . . . . . . . . 56
5.16 Pore size distribution of the first membranes . . . . . . . . . . . . . . . 57
5.17 Gaskets for the first membrane cell . . . . . . . . . . . . . . . . . . . . 58
5.18 Flow rate influence at different temperatures . . . . . . . . . . . . . . . 58
5.19 Gas separation with different volume flows . . . . . . . . . . . . . . . . 59
5.20 Gas with different feed gases . . . . . . . . . . . . . . . . . . 60
5.21 Experimental and theoretic selectivity . . . . . . . . . . . . . . . . . . . 61
5.22 Problem of the first membrane cell . . . . . . . . . . . . . . . . . . . . 62
5.23 First version of the secondary membrane cell . . . . . . . . . . . . . . . 63
5.24 Final design of the modified membrane cell . . . . . . . . . . . . . . . . 63
5.25 Axial section view of the modified membrane cell . . . . . . . . . . . . 64
5.26 Pore distribution of PZ-2 . . . . . . . . . . . . . . . . . . . . . . . . . . 67
5.27 Graphite gaskets around membrane . . . . . . . . . . . . . . . . . . . . 68
5.28 Performance of membrane cells in <H ;N > . . . . . . . . . . . . . . . 692 2
5.29 Influence of temperature in <H ;N > . . . . . . . . . . . . . . . . . . . 702 2
5.30 Influence of temperature in <2M;N > . . . . . . . . . . . . . . . . . . 702
5.31 Influence of equivalent water to cement ratio in <2M;N > . . . . . . . 712
5.32 Influence of pore size in <2M;N > . . . . . . . . . . . . . . . . . . . . 722
5.33 Effect of different sample thickness on diffusion in <2M;N > . . . . . . 732
5.34 Membranes after heating . . . . . . . . . . . . . . . . . . . . . . . . . . 74
5.35 Comparison of compositions in <5M;N > . . . . . . . . . . . . . . . . 752