development of techniques for in-situ measurement of heat and mass transfer in ammonia-water ...

310 Pages·2007·3.41 MB·English

DEVELOPMENT OF TECHNIQUES FOR IN-SITU MEASUREMENT
OF HEAT AND MASS TRANSFER IN AMMONIA-WATER
ABSORPTION SYSTEMS

A Dissertation
Presented to
The Academic Faculty

By

Sangsoo Lee

In Partial Fulfillment
Of the Requirements for the Degree
Doctor of Philosophy in Mechanical Engineering

Georgia Institute of Technology

August 2007
DEVELOPMENT OF TECHNIQUES FOR IN-SITU MEASUREMENT
OF HEAT AND MASS TRANSFER IN AMMONIA-WATER
ABSORPTION SYSTEMS

Approved by:

Dr. Srinivas Garimella, Advisor Dr. Amyn Teja
G. W. Woodruff School of Mechanical School of Chemical and Biomolecular
Engineering Engineering
Georgia Institute of Technology Georgia Institute of Technology

Dr. S. Mostafa Ghiaasiaan Dr. Tom Fuller
G. W. Woodruff School of Mechanical School of Chemical and Biomolecular
Engineering Engineering
Georgia Institute of Technology Georgia Institute of Technology

Dr. Sheldon M. Jeter
G. W. Woodruff School of Mechanical
Engineering Date Approved: 28th of June 2007
Georgia Institute of Technology
To my parents – Their endless love and dedication all through their life
To my uncle and aunt –- Their support, trust and belief in my ability
To my sister and brother-in-law – Their efforts of taking care of my parents during my
absence
To my other family – My fountain of joys and happiness
To my friends – Their valuable advice
To my God – Directing me to the way I need to go
I appreciate all of you and I could not be in this position without all your support
and dedication.
ACKNOWLEDGEMENTS
I would like to thank my advisor Dr. Srinivas Garimella for supporting me for five
years and his continuous efforts to bring the best out of me. The improvements I have
earned through his guidance will help me for the rest of my career.
I would like to thank Lalit Bohra and Matt Determan for their cooperation and
assistance in fabricating the test facility, which helped me get over several huddles.
Discussion and collaboration with Mr. Bohra also provided invaluable guidance to me.
I would like to thank Brain Fronk and Todd Bandhauer for revising and making
corrections to my thesis. I also would like to thank all STSL members: Jesse Killion,
Akhil Agarwal, Biswajit Mitra, Vishwanath Subramanium, Ulf Andresen, and others.
Together, they formed a good support structure and they always listened my questions.
Without these, I would have never made it through.
Finally, I would like to thank my Ph.D. Reading Committee for their guidance and
encouragement.

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TABLE OF CONTENTS
ACKNOWLEDGEMENTS.....................................................................................iv
LIST OF TABLES.................................................................................................ix
LIST OF FIGURES...............................................................................................xi
NOMENCLATURE .............................................................................................xvi
SUMMARY..........................................................................................................xx
CHAPTER 1. INTRODUCTION.........................................................................1
1.1 Background................................................................................................1
1.2 Issues of Ammonia-Water Absorption .......................................................3
1.3 Scope of the Research..............................................................................5
1.3.1 Objectives of the Current Research....................................................5
1.4 Organization of Thesis...............................................................................5
CHAPTER 2. LITERATURE REVIEW...............................................................6
2.1 Component Level.......................................................................................6
2.2 Falling-Film Absorption..............................................................................9
2.2.1 Heat and Mass Transfer Processes....................................................9
2.2.2 Experimental Work...........................................................................11
2.2.3 Relevant Studies...............................................................................18
2.3 Bubble Absorption ...................................................................................28
2.4 Miniaturization of Absorbers....................................................................33
2.5 Summary of Literature.............................................................................39
2.6 Research Needs......................................................................................42
2.7 Objectives of the Present Study...............................................................43
CHAPTER 3. EXPERIMENTAL APPROACH..................................................57
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3.1 Test Matrix Design...................................................................................57
3.2 Design Specifications...............................................................................58
3.3 Test Facility Overview..............................................................................60
3.4 Details of Individual Components ............................................................64
3.4.1 Absorber and Absorber Coolant Loop..............................................64
3.4.2 Desorber and Desorber Heating Loop..............................................70
3.4.3 Condenser and Condenser Coolant Loop........................................73
3.4.4 Evaporator and Evaporator Heating Loop........................................75
3.4.5 Separator..........................................................................................76
3.4.6 Rectifier and Rectifier Coolant Loop.................................................77
3.4.7 Solution Heat Exchanger..................................................................78
3.4.8 Pre-Cooler........................................................................................79
3.4.9 Expansion Valve...............................................................................80
3.4.10 Pressure Reduction Valve................................................................81
3.4.11 Solution Pump..................................................................................82
3.5 Instrumentation........................................................................................89
3.5.1 Temperature and Pressure Measurements......................................89
3.5.2 Flow Meters......................................................................................89
3.5.3 Data Acquisition................................................................................93
3.6 Tailoring the Test Facility for Wide Operating Range ..............................94
3.6.1 Two-Pressure Operation...................................................................95
3.6.2 Absorber Solution Inlet .....................................................................96
3.6.3 Solution Pumping..............................................................................97
3.6.4 High-Side Pressure Regulation ........................................................97
3.6.5 Refrigeration Flow Rate Measurement.............................................98
3.6.6 Extreme Pressure and Concentration Conditions.............................98
3.6.7 Absorber Coolant Temperature Difference.....................................100
3.7 Experimental Procedures.......................................................................101
3.7.1 Safety Precautions..........................................................................101
3.7.2 Leak Testing and Charging.............................................................102
3.7.3 Testing............................................................................................103
3.8 Test Conditions......................................................................................107
CHAPTER 4. DATA ANALYSIS....................................................................113
4.1 Ammonia/Water Mixture Properties.......................................................113
4.1.1 Ammonia/Water Properties.............................................................113
4.2 Calculation Methodology........................................................................116
4.2.1 Concentration Range......................................................................121
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4.3 Heat Transfer Calculations....................................................................124
4.3.1 Absorber Calculations.....................................................................124
4.3.1.1 Selection of LMTD...................................................................126
4.3.1.2 Overall Heat Transfer Coefficient............................................127
4.3.1.3 Coolant Side Heat Transfer Coefficient...................................127
4.3.1.4 Solution Heat transfer Coefficient............................................128
4.3.2 Desorber Calculations....................................................................129
4.3.3 Evaporator Calculations..................................................................130
4.3.4 Condenser Calculations..................................................................131
4.3.5 Rectifier Calculation........................................................................133
4.4 Mass Transfer Calculations...................................................................134
4.4.1 Absorber Inlet Vapor Condition Change.........................................134
4.4.2 Solution Temperature Profile..........................................................135
4.4.3 Calculation of Overall Mass Transfer Coefficient in Vapor-Phase..137
4.4.3.1 Mass Transfer with Binary Mixtures in Vapor Phase...............137
4.4.3.2 Colburn-Drew Method for Binary Mixtures in Vapor Phase.....142
4.4.3.3 Interface Conditions and Heat Regions...................................143
4.4.3.4 Calculation of Condensing Flux Concentration........................147
4.4.3.5 Calculation of Vapor Mass Transfer Coefficient.......................148
4.4.4 Calculation of Overall Mass Transfer Coefficient in Liquid Phase ..149
4.4.4.1 Mass Transfer with Binary Mixtures in Liquid Phase...............150
4.5 Energy Balances and Uncertainties for the Current Experiments..........151
4.5.1 Component Energy Balances.........................................................151
4.5.2 Uncertainty Calculations.................................................................152
CHAPTER 5. RESULTS................................................................................155
5.1 Overall Heat Transfer Results................................................................155
5.1.1 Absorber Heat Duty........................................................................155
5.1.2 Overall Heat Transfer Coefficient ...................................................156
5.1.3 Solution Heat Transfer Coefficient..................................................157
5.1.4 Effect of Dilute Solution Concentration...........................................159
5.1.5 Effect of Absorber Pressure............................................................163
5.1.6 Relevant Non-Dimensional Parameters..........................................166
5.1.7 Comparison with Literature.............................................................169
5.2 Overall Mass Transfer Results in Vapor-Phase.....................................175
5.2.1 Mass Transfer Coefficient...............................................................176
5.2.2 Effect of Dilute Solution Concentration...........................................177
5.2.3 Effect of Absorber Pressure............................................................180
5.2.4 Relevant Non-Dimensional Parameters..........................................186
5.2.5 Comparison with Literature.............................................................186
5.3 Overall Mass Transfer Results in Liquid-phase .....................................189
5.3.1 Mass Transfer Coefficient...............................................................189
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5.3.2 Effect of Dilute Solution Concentration...........................................190
5.3.3 Effect of Absorber Pressure............................................................193
5.3.4 Relevant Non-Dimensional Parameters..........................................198
5.3.5 Comparison with Literature.............................................................198
5.4 Range of Uncertainties for the Current Experiments .............................201
CHAPTER 6. HEAT AND MASS TRANSFER MODEL DEVELOPMENT.....204
6.1 Heat Transfer Correlation Development................................................204
6.2 Mass Transfer Correlation Development...............................................209
6.2.1 Mass Transfer Correlation in Vapor-Phase.....................................209
6.2.2 Mass Transfer Correlation in The liquid-phase...............................216
CHAPTER 7. CONCLUSIONS AND RECOMMENDATIONS........................223
7.1 Conclusions...........................................................................................223
7.2 Recommendations.................................................................................226
7.2.1 Flow Mode and Local-Level Analyses............................................226
7.2.2 Variations in Absorber Geometry....................................................227
7.2.3 Test Facility Design and Experimental Procedures........................228
7.2.4 Absorption System with Other Working Fluid Pair..........................229
APPENDIX A: TEST CONDITIONS FOR THE REPRESENTATIVE DATA POINT
.........................................................................................................................231
APPENDIX B: REPRESENTATIVE CALCULATIONS FOR HEAT DUTY, HEAT
AND MASS TRANSFER COEFFICIENTS.......................................................235
APPENDIX C: OVERALL, COOLANT, AND SOLUTION HEAT TRANSFER
COEFFICIENTS...............................................................................................255
APPENDIX D: UNCERTAINTY CALCULATIONS............................................268
D.1 Sample Uncertainties.................................................................................269
D.2 Range of Uncertainties of Solution and Vapor Properties..........................276
D.3 Validity of the Kinetic Theory for Vapor Property Evaluation......................276
REFERENCES.................................................................................................282

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LIST OF TABLES
Table 2.1 Summary at the Relevant Studies at the Component Level...............45
Table 2.2 Summary of Relevant Experimental Studies on Falling–Film Absorption
.................................................................................................................47
Table 2.3 Summary of Relevant Studies on Falling–Film Absorption.................50
Table 2.4 Summary of Relevant Studies on Bubble Absorption.........................54
Table 2.5 Summary of Relevant Studies on Miniaturization of Absorber............55
Table 3.1 Design of Test Matrix..........................................................................58
Table 3.2 Absorber Geometry............................................................................68
Table 3.3 Component Specifications..................................................................84
Table 3.4 Instrumentation Specifications Summary............................................92
Table 3.5 Test Conditions for the Present Study..............................................108
Table 3.6 Primary Challenges and Techniques Used.......................................109
Table 4.1 Condensing Flux, Vapor Interface, and Bulk Vapor Concentrations.148
Table 4.2 Energy Balances for Absorber, Condenser and Evaporator.............151
Table 4.3 Uncertainties of the Pressure Transducers.......................................153
Table 4.4 Uncertainties of the Solution and Coolant Flow Meters....................154
Table 5.1 Summary of Relevant Heat Transfer Studies ...................................171
Table 5.2 Parametric Effect of Test Conditions on the Mass Transfer Coefficient
in the Vapor–Phase..........................................................................................185
Table 5.3 Parametric Effect of Test Conditions on the Mass Transfer Coefficient
in the Liquid–Phase..........................................................................................197
Table 5.4 Uncertainties in the Current Experimental Data................................203
Table 6.1 Range of Validity of Heat and Mass Transfer Correlations...............222
APPENDIX A. Representative Data Point........................................................232
APPENDIX B. Representative Data Analysis...................................................236
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Table D.1 List of Parameters included in Uncertainty Analysis for Absorber (345
kPa, 25%, 0.026 kg/s) ......................................................................................270
Table D.2 Sample Uncertainties in Main Parameters of Interest......................272
Table D.3 Uncertainties in the Solution and Vapor Properties in the Present
Study ...............................................................................................................279
Table D.4 Uncertainties in Non-Dimensional Vapor Parameters......................281

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