Development of Pilot-scale Reactor for the Production Of Aluminium Hydroxide from Alum DerivedFrom Kankara Kaolin for Zeolite Y Synthesis
Development 0f a Pilot-scale Reactor for the Production Of Aluminium Hydroxide from Alum Derived From Kankara Kaolin for Zeolite Y Synthesis.
ABSTRACT
This work was aimed at the design and fabrication of a pilot-scale reactor for the production of aluminium hydroxide from aluminium sulphate obtained from Kankara kaolin for use in Zeolite Y synthesis.
XRD, XRF and BET analyses were carried out on the aluminium hydroxide first prepared at bench scale and pilot scale. The aluminium hydroxide precipitated on a laboratory bench scale at the pH value of 6 was found to be amorphous while that precipitated at a pH value of 7 was found to be a crystalline mix of boehmite and bayerite.
The BET surface area of aluminium hydroxide precipitated at the laboratory bench scale was found to be 78.275m2 /g for a pH value of 6 and 209.799m2 /g for a pH value of 7. The effect of temperature on the amount of aluminium hydroxide precipitated was found to be marginal.
From the kinetic studies of the precipitation reaction for aluminium hydroxide, the reaction was found to be pseudo-first order with respect to aluminium sulfate. The activation energy and pre-exponential factor of the precipitation reaction were found to be 102kJ/mole and 1.15×1014/sec respectively.
Zeolite Y was synthesized using the aluminium hydroxide produced from Kankara kaolin on a laboratory bench scale. A pilot-scale semi-batch reactor was designed for the production of aluminium hydroxide and conversion of 99.98% of aluminium sulphate reactant was obtained.
A pilot-scale semi-batch reactor with a capacity of 10.448kg per day for the production of aluminium hydroxide was fabricated and test run, and produced good quality aluminium hydroxide with a BET surface area of 97.73m2 /g for the first run and 227.779m2 /g for the second run.
TABLE OF CONTENTS
TITLE PAGES
Title page – – – – – – – – – – i
Declaration – – – – – – – – – – ii
Certification – – – – – – – – – – iii
Dedication – – – – – – – – – – iv
Acknowledgement – – – – – – – – – v
Abstract – – – – – – – – – – vi
Table of contents – – – – – – – – – vii
List of figures – – – – – – – – – – xi
List of tables – – – – – – – – – – xiii
List of plates – – – – – – – – – – xiv
List of appendices – – – – – – – – – xv
Abbreviations – – – – – – – – – xvi
CHAPTER ONE
1.0 INTRODUCTION – – – – – – – – 1
1.1 Research Problem – – – – – – – – 2
1.2 Research Scope – – – – – – – – 2
1.3 Research Aim and Objectives – – – – – –
CHAPTER TWO:SURVEY OF LITERATURE
2.1 Catalysis – – – – – – – – – 4
2.1.1 Backgroundof catalysis – – – – – – – 5
2.1.2 Catalysis and reaction energetics – – – – – – 7
2.1.3 Typical catalytic materials – – – – – – – 8
2.1.4 Types of catalysis – – – – – – – – 9
2.1.5 Significance of catalysis – – – – – – – 11
2.2 Fluid Catalytic Cracking (FCC) – – – – – – 12
2.2.1 FCC Catalysts – – – – – – – – 13
2.3 Zeolites – – – – – – – – 14
2.3.1 Zeolite structure – – – – – – – – 15
2.3.2 Zeolite synthesis – – – – – – – – 16
2.3.3 Use of zeolites in the petrochemical industry – – – – 19
2.4 Alumina – – – – – – – – – 20
2.4.1 Properties of alumina – – – – – – – 20
2.4.2 Structure of alumina – – – – – – – 21
2.4.3 Production of alumina – – – – – – – 22
2.4.4 Applications of alumina – – – – – – – 24
2.5 Bauxite – – – – – – – – – 25
2.5.1 Bauxite formation – – – – – – – – 25
2.5.2 Production trends of bauxite – – – – – – 26
2.6 Aluminium Hydroxide – – – – – – – 27
2.6.1 Properties of aluminiumhydoxide – – – – – – 29
2.6.2 Production of aluminium hydroxide – – – – – – 29
2.6.3 Uses of aluminium hydroxide – – – – – – 30
2.7 Gibbsite – – – – – – – – – 31
2.7.1 Structure of gibbsite – – – – – – – – 31
2.8 Boehmite – – – – – – – – – 32
2.9 Pseudoboehmite – – – – – – – – 33
2.9.1 Morphology of pseudoboehite – – – – – – 33
2.9.2 Synthesis of pseudoboehmite – – – – – – 34
2.9.3 Uses of pseudoboehmite – – – – – – – 35
2.10 Clay Minerals – – – – – – – – 35
2.10.1 Structureof clay minerals – – – – – – – 36
2.10.2 Formation of clay minerals – – – – – – – 37
2.10.3 World production of clays – – – – – – – 37
2.11 Kaolinite – – – – – – – – – 38
2.11.1 Structural transformations of kaolin – – – – – – 39
2.11.2 Occurrenceof kaolin – – – – – – – 40
2.11.3 Uses of kaolin – – – – – – – – 41
2.12 Chemical Reactors – – – – – – – – 42
2.12.1 Typesof chemical reactors – – – – – – – 44
2.12.2 Design of a semi-batch reactor – – – – – – 53
2.13 Related Works – – – – – – – – 56
CHAPTER THREE: MATERIALS AND METHODS
3.1 Materials – – – – – – – – – 58
3.2 Apparatus – – – – – – – – – 58
3.3 Equipment – – – – – – – – – 59
3.4 Experimental Procedure – – – – – – – 59
3.4.1 Hydroxylation of the aluminiumsulphate using sodium hydroxide – 59
3.4.2 Characterisation of aluminium hydroxide prepared – – – – 60
3.4.3 Design of pilot scale reactor – – – – – – 61
3.4.4 Fabrication of pilot scale reactor – – – – – – 62
3.4.5 Test-run of pilot scale reactor – – – – – – 62
3.4.6 Determination of kinetic parameters for aluminium hydroxide production – 62
3.4.7 Specific design of the semi-batch pilot scale reactor – – – 63
CHAPTER FOUR: RESULTS AND DISCUSSION
4.1 Effect of temperature on the mass of Al(OH)3produced – – – 66
4.2 Chemical composition of aluminium hydroxide obtained from alum on
Laboratory bench scale – – – – – – – 67
4.3 Crystal phases of aluminium hydroxide produced from alum from Kankara
kaolin on a laboratory scale – – – – – – 68
4.4 Surface area and pore analysis of aluminium hydroxide produced from alum
from Kankara kaolin on a laboratory bench scale – – – 69
4.5 Kinetic Data determination using the differential method of analysis for the
production of aluminium hydroxide from alum from Kankara kaolin – 70
4.6 Design of pilot scale reactor – – – – – – 75
4.7 Fabrication of pilot scale reactor – – – – – – 76
4.8 Crystal phases of aluminium hydroxide produced from alum from Kankara
kaolin from the pilot-scale reactor- – – – – – – 78
4.9 Chemical composition of aluminium hydroxide produced from alum from
Kanaka kaolin from the pilot-scale reactor – – – – 79
4.10 Surface area and pore analysis of aluminium hydroxide produced
from alum from Kanakara kaolin from the pilot-scale reactor – – 80
4.11 Crystal phase of Zeolite Y produced from Kankara kaolin based aluminium
hydroxide – – – – – – – – – 81
CHAPTER FIVE: SUMMARY, CONCLUSIONS AND RECOMMENDATION
5.1 Summary – – – – – – – – – 82
5.2 Conclusions – – – – – – – – – 82
5.3 Recommendation – – – – – – – – 82
REFERENCES – – – – – – – – – 84
INTRODUCTION
The need for an increase in the lighter fractions obtained during petroleum processing led to the cracking of the heavy oil fractions gotten from distillation.
There are two methods by which this is achieved which are thermal cracking and catalytic cracking. Over the years catalytic cracking has surmounted thermal cracking as the principal process adopted for the cracking of heavier oil fractions.
This is due to the effect of the catalyst in catalytic cracking that lowers the activation energy of the chemical reactions, thereby enabling the conversion of the heavy oil fractions at relatively low temperatures of 500-6000C compared to 750- 9000C obtained in thermal cracking.
Also, there is an improved yield and quality of the product obtained by catalytic cracking as compared with thermal cracking.
Catalytic cracking occurs in a fluid catalytic cracking (FCC) unit in the presence of a catalyst. The catalyst is made up of zeolite dispersed in a catalyst matrix, binders and fillers. The catalyst matrix is primarily made up of active alumina.
The relative percentages of these components in catalyst formulation affect the performance of the catalyst. These zeolites are incorporated in the matrix because alone they are expensive and catalytically too active to be used in FCC units of practical dimensions due to severe heat transfer requirements.
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CSN Team.
