Coalescence, Breakup and Liquid Circulation in Bubble Column Reactors

Acknowledgement				v
Abstract				vii
1	Introduction 403kb			1
	1.1	Motivation for the Thesis		1
		1.1.1	Importance of bubble column reactors	1
		1.1.2	The importance of reactor modeling	6
		1.1.3	The need for determining model parameters	7
	1.2	Problem Formulation		9
		1.2.1	Overview	9
		1.2.2	Coalescence and breakup rates	10
		1.2.3	Liquid circulation	12
		1.2.4	Dynamic gas disengagement	13
2	Experimental 479kb			15
	2.1	Experimental Apparatus		15
	2.2	Measurement Principle		17
		2.2.1	The five-point probe of Burgess and Calderbank	17
		2.2.2	The five-point probe of Steinemann and Buchholz	19
	2.3	Estimation of the Bubble Parameters		20
		2.3.1	Technique of Burgess and Calderbank	20
		2.3.2	Technique of Steinemann and Buchholz	22
	2.4	Experimental Results		23
	2.5	Conclusion		31
3	Coalescence and Breakup 962kb			33
	3.1	Introduction		33
	3.2	Binary Bubble Coalescence		37
		3.2.1	Binary bubble collision frequency	38
		3.2.2	Coalescence efficiency	40
	3.3	Model for Bubble Breakup		43
		3.3.1	Arrival or bombarding frequency of eddies	44
		3.3.2	Breakage probability (efficiency)	46
		3.3.3	The expression for breakage rate	49
		3.3.4	Breakage kernel or breakage size distribution	50
	3.4	Results and Discussion		52
		3.4.1	Coalescence efficiency	52
		3.4.2	Specific coalescence rate	54
		3.4.3	Breakage kernel	58
		3.4.4	Specific breakage rate	61
	3.5	Conclusion		62
4	Approach of Two Fluid Particles 824kb			65
	4.1	Introduction		66
	4.2	Simple Parallel-Film Model		67
		4.2.1	Expression of film area	67
		4.2.2	Expression for interaction time	72
		4.2.3	Virtual mass coefficient	73
	4.3	General Parallel-Film Model		75
	4.4	Results and Discussion		80
		4.4.1	Zero external force	80
		4.4.2	Effect of external forces	85
		4.4.3	Effect of virtual mass	87
		4.4.4	Comparison with experimental data	88
	4.5	Conclusion		92
5	Local Bubble Size Distribution 521kb			95
	5.1	Introduction		95
	5.2	Population Balance Model		97
		5.2.1	Equations of balance	97
		5.2.2	Viscous and buoyancy coalescence	101
		5.2.3	Energy dissipation rate	103
		5.2.4	Boundary conditions	104
	5.3	Results and Discussion		105
	5.4	Conclusion		110
6	Liquid Circulation 1157kb			113
	6.1	Introduction		113
	6.2	Pseudo-Homogeneous Fluid Model		117
		6.2.1	Equation of motion	124
		6.2.2	Expression of liquid velocity	121
	6.3	Two-Fluid Model		124
		6.3.1	Equation of motion	124
		6.3.2	Expression of liquid velocity	127
	6.4	Results and Discussion		129
		6.4.1	Pseudo-homogeneous model	129
		6.4.2	Two-fluid model	138
	6.5	Conclusion		144
7	Dynamic Gas Disengagement 1078kb			147
	7.1	Introduction		147
	7.2	Experimental Technique and Data Treatment		151
	7.3	Holdup Structure and Rise Velocities		154
	7.4	Non-Uniform Distribution		159
	7.5	Bubble Size and Specific Interfacial Area		160
	7.6	Results and Discussion		162
		7.6.1	Bubble size and interfacial area	162
		7.6.2	Non-uniform distribution	169
	7.7	Conclusion		171
8	Conclusions and Recommendations 422kb			173
	8.1	Conclusions		173
8.2	Recommendations			175
Nomenclature				177
Bibliography 380kb				185