Crystallization of inorganic compounds [Elektronische Ressource] : scaling in seawater desalination / von Ali Mousa Al-Atia

Ali Al-Atia

Informations

• Publié par: martin-luther-universitat_halle-wittenberg
• Publié le: 01 janvier 2008
• Nombre de lectures: 33
• Langue: English
• Poids de l'ouvrage: 1 Mo

Extrait

Crystallization of Inorganic Compounds – Scaling in Seawater
Desalination






Eingereicht am Zentrum für Ingenieurwissenschaften
Martin-Luther-Universität Halle-Wittenberg



zur Erlangung des akademischen Grades
Doktor-Ingenieur (Dr.-Ing.)
genehmigte



Dissertation



von

M.Sc. Chem. Eng. Ali Mousa Al-Atia
geboren 6. Mai 1977 in Bagdad, Irak



Gutachter:
1. Prof. Dr.-Ing. habil. J. Ulrich
2. Prof. Dr. Schulte

Halle (Saale), 08. December 2008

urn:nbn:de:gbv:3-000014874
[http://nbn-resolving.de/urn/resolver.pl?urn=nbn%3Ade%3Agbv%3A3-000014874]


Dedication


I dedicate this work to my father, who passed away while I am far away from
him busy with this work, may God bless his soul, and to my mother who is proud of
me as I am proud of her.

Dad... You are always in my thoughts!









































Acknowledgment


I wish to express my deepest gratitude and sincere appreciation to my
supervisor Prof. Joachim Ulrich, for his supervision, guidance and helpful suggestion
throughout the research work.
I would like to acknowledge the financial support by the DAAD for my PhD work in
Germany.

Also, special thanks to the staff of department of thermal separation processes
who offered great help and cooperation. I would like to thank Dr. Matthew Jones,
Helmut Weißbarth, Severine Dette, Kathrin Jäger, Isolde Trümper, Nadine Pachulski
and Caner Yürüdü.
Last but not least, I am very grateful to my entire family for their moral support.
To each and every one of you - thank you!

Halle (Saale), August 2008
Table of content


1 Introduction ……………………………………………………………….. 1

2 State of the Art.................................................................................... 2

Effects of Additives on the MSZ Width

2.1 Electrolyte solutions…………………………………………………………... 2
2.2 Thermodynamics of ion solvation…………………………………………… 2
4 2.3 Solubility and nucleation ……………………………………………………..
2.4 Metastable zone width and influence of the additive……………………… 8
2.5 Induction time………………………………………………………………..... 9

Scale Reduction in Seawater

2.6 Seawater composition and saturation state………………………….......... 11
2.7 Chemical definition of scales………………………………………………… 13
2.7.1 The alkaline scale……………………………………………………... 13
2.7.2 The non alkaline scale………………………………………………... 13
2.8 Desalination methods………………………………………………………… 14
15 2.9 Problems caused by scaling.…………………………………………………
2.9.1 Thermal technologies…………………………………………………. 15
2.9.2 Membrane technologies……………………………………………… 15
2.10 Methods of scale reduction; disadvantages………………………………... 15
2.11 Aims of research work………………………………………………………... 16
2.12 Present work methodology ………………………………………………….. 17
2.12.1 Suggested rule to select the additives……………………………… 17
2.12.2 Suggested methods to reduce scaling in seawater desalination… 18


3 Experimental Work………………………………………………………. 20

3.1 Polythermal and isothermal methods……………………………………….. 20
3.1.1 The effect of inorganic impurities on the width of the metastable
zone…………………………………………………………………….. 20
22 3.1.2 Induction time of calcium carbonate in artificial seawater…………
3.2 Fluidized bed crystallizer……………………………………………………... 23
3.2.1 Seeds of natural calcite………………………………………………. 23
3.2.2 The hot finger technique……………………………………………… 25
3.3 Ultrasonic irradiation………………………………………………………….. 26



4 Table of content

4 Results………………………………………………………….................... 28

MSZ Width Results

4.1 The effect of selected inorganic additives on the MSZ width of inorganic
compounds…………………………………………………………………….. 28
4.1.1 The effects of Al (SO ) , FeSO , BaCl , Li SO and K SO on the 2 4 3 4 2 2 4 2 4
MSZ width of ZnSO ……….…………………………………………. 4 28
4.1.1.1 The effect of Al (SO ) on the MSZ width of ZnSO …………. 29 2 4 3 4
31 4.1.1.2 The effect of FeSOi …………….. 4 4
32 4.1.1.3 The effect of BaCl on the MSZ width of ZnSO ……………… 2 4
34 4.1.1.4 The effect of Li SOi …………….. 2 4 4
4.1.1.5 The effect of K SOidth of ZnSO …………….. 35 2 4 4
4.1.2 The effects of AlCl , FeCl , MgCl and BaCl on the MSZ width of 3 2 2 2
LiCl……………………………………………………………………… 37
4.1.2.1 The effect of AlCl on the MSZ width of LiCl…………………. 37 3
4.1.2.2 The effect of FeCli 38 2
4.1.2.3 The effect of MgClidth of LiCl………………… 40 2
4.1.2.4 The effect of BaCl on the MSZ wi 41 2
4.1.3 The effects of CuSO , BaCl and Li SO on the MSZ width of 4 2 2 4
K SO …………………………………………………………………… 2 4 43
4.1.3.1 The effect of CuSO on the MSZ width of K SO .................... 43 4 2 4
4.1.3.2 The effect of BaCl on the MSZ wi SO ...................... 44 2 2 4
4.1.3.3 The effect of Li SO on the MSZ width of K SO .................... 46 2 4 2 4
4.2 Determination the induction time of CaCO in artificial seawater………... 48 3
4.2.1 Induction time at 35 g/kg salinity…………………………………….. 49
4.2.1.1 Effect of NaHCO addition on the induction time of CaCO .. 49 3 3
4.2.1.2 Induction time of CaCO as a function of supersaturation 3
and temperatures (30, 40, 50 and 70 °C)………………………. 50
4.2.2 Induction time at 55 g/kg salinity…………………………………….. 51
4.2.2.1 Effect of NaHCO addition on the induction time of CaCO .. 51 3 3
4.2.2.2 Induction time of CaCO as a function of supersaturation 3
and temperatures (30, 50 and 70 °C)…………………………… 52

Scale Reduction Results

4.3 Reduction of CaCO by seeding; without chemical addition…………….. 53 3
4.4 by a hot finger; without chemical addition………… 53 3
4.5 by precipitation; supersaturation modified by 3
NaHCO ………………………………………………………………………... 3 54
4.5.1 Reduction of calcium ion versus NaHCO addition……………….. 54 3
5 Table of content

56 4.5.2 Reduction of calcium ion versus operational temperature………...
4.5.3 Reduction of calcium ion versus operational time, power of
58 ultrasound and salinity………………………………………………...


5 Discussion………………………………………………………………….. 60

5.1 The effect of additives on the MSZ width………………………………….. 60
5.1.1 ZnSO -H O solution………………………………………………...… 60 4 2
5.1.1.1 Effect of Al (SO ) …………………………………………………. 60 2 4 3
5.1.1.2 Effect of FeSO …………………………………………………….. 61 4
5.1.1.3 Effect of BaCl ……………………………………………………… 61 2
5.1.1.4 Effect of Li SO 62 2 4
5.1.1.5 Effect of K SO ........................................................................... 63 2 4
5.1.2 LiCl-H O solution……………………………………………………… 64 2
5.1.2.1 Effect of AlCl ………………………………………………………. 64 3
5.1.2.2 Effect of FeCl ……………………………………………………… 65 2
5.1.2.3 Effect of MgCl …………………………………………………….. 65 2
5.1.2.4 Effect of BaCl 66 2
5.1.3 K SO -H O solution…………………………………………………… 67 2 4 2
5.1.3.1 Effect of CuSO 67 4
5.1.3.2 Effect of BaCl 67 2
68 5.1.3.3 Effect of Li SO 2 4
5.2 The induction time of CaCO in artificial seawater………………………… 69 3
5.2.1 Effect the mass addition of NaHCO at 35 and 55 g/kg salinity 3
(Sa.) ……………………………………………………………………. 71
5.2.2 Interfacial tension (surface energy) of CaCO in ASW……………. 73 3
5.3 Scale reduction of CaCO in seawater desalination………………………. 75 3
5.3.1 Crystal growth…………………………………………………………. 75
75 5.3.2 Precipitation…………………………………………………………….
5.3.2.1 Calcium ion reduction as a function of NaHCO mass and 3
temperature………………………………………………………… 76
5.3.2.2 Operational time of ultrasound, power of ultrasound and
salinity change…………………………………………………….. 77
5.3.3 An environmentally friendly and economically solution to reduce
77 scaling…………………………………………………………………..

6 Conclusion………………………………………………………………….. 80
7 Summary…………………………………………………………………….. 82
8 Nomenclature……………………………………………………………… 84
9 References 86
6 Introduction

1. Introduction

There is a big effort in developing techniques to improve the seawater
desalinisation. That means to reduce the costs of fresh water and to reduce the
impacts on environment.

One of the most important factors that contribute to high production costs of
fresh water from seawater in desalination is scale formation (encrustation). Scale
formation e.g. CaCO in seawater desalination is a crystallization phenomenon. This 3
phenomenon can be defined as crystallization of inorganic compounds in a multi-
component solution (seawater). This type of crystallization is considered to be
complicated, since the crystallization process is influenced by the compounds which
exist in seawater and the complex plant operational conditions.
Most known techniques that are used to reduce the encrustation in seawater
desalination are not based on crystallization processes as will be shown in the next
chapters. On this account, the motivation of this work is to find alternative
technologies to reduce the e