ANAEROBIC FERMENTATION OF RICE STRAW AND CHICKEN MANURE TO CARBOXYLIC ...

223 Pages·2005·0.91 MB·English

ANAEROBIC FERMENTATION OF RICE STRAW AND CHICKEN MANURE
TO CARBOXYLIC ACIDS

A Dissertation
by
FRANK KWESI AGBOGBO

Submitted to the Office of Graduate Studies of
Texas A&M University
in partial fulfillment of the requirements for the degree of

DOCTOR OF PHILOSOPHY

December 2005

Major Subject: Chemical Engineering
ANAEROBIC FERMENTATION OF RICE STRAW AND CHICKEN MANURE
TO CARBOXYLIC ACIDS

A Dissertation
by
FRANK KWESI AGBOGBO

Submitted to the Office of Graduate Studies of
Texas A&M University
in partial fulfillment of the requirements for the degree of

DOCTOR OF PHILOSOPHY

Approved by:
Chair of Committee, Mark T. Holtzapple
Committee Members, Richard R. Davison
Mahmoud M. El-Halwagi
Cady Engler
Head of Department, Kenneth R. Hall

December 2005

Major Subject: Chemical Engineering
iii
ABSTRACT

Anaerobic Fermentation of Rice Straw and Chicken Manure to Carboxylic Acids.
(December 2005)
Frank Kwesi Agbogbo, B.Sc., University of Science and Technology, Kumasi, Ghana
Chair of Advisory Committee: Dr. Mark T. Holtzapple

In this work, 80% lime-treated rice straw and 20% lime-treated chicken manure
were used as substrates in rotary fermentors. Countercurrent fermentation was
performed at various volatile solid loading rates (VSLR) and liquid residence times
(LRT). The highest acid productivity of 1.69 g/(L·d) was at a total acid concentration of
32.4 g/L. The highest conversion and yield were 0.692 g VS digested/g VS fed and 0.29
g total acids/g VS fed, respectively. The continuum particle distribution model (CPDM)
was used to predict product concentrations at various VSLR and LRT. CPDM predicted
the experimental total acid concentration and conversion at an average error of 6.41%
and 6.55%, respectively.
A fixed-bed fermentation system was designed to perform pretreatment and
fermentation in the same unit. High product concentrations (~48 g/L) as well as high
conversions (0.741 g VS digested/g VS fed, F4, Train B) were obtained from the same
fermentor. CPDM was extended to predict product concentrations in the fixed-bed
fermentation system. The model gave a good estimate of the product concentrations and
retention time.
After biomass fermentation, the residue can be combusted to generate heat. For
pretreatment purposes, the use of ash can replace lime. A study was performed using
ash as a potential pretreatment agent. Ash from raw poplar wood was effective in
pretreating poplar wood; however, ash from bagasse fermentation residues was not
useful in pretreating bagasse.
Previous modeling studies indicate that a conversion of 95% could be achieved
with bagasse using countercurrent fermentation. Because lignin constitutes 13% of the
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dry weight of bagasse, this means lignin would have to be digested to obtain a
conversion of 95%. Experiments on the fermentation of enzymatically liberated lignin
from both poplar wood and bagasse do not show that solubilized lignin was fermented
to organic acids by using a mixed culture of marine microorganisms.
Two buffer systems (ammonium bicarbonate and calcium carbonate) were used
to compare product concentrations of carboxylic acid fermentations using office paper
and chicken manure. It has been demonstrated that the total product concentration using
ammonium bicarbonate is almost double the product concentration using calcium
carbonate.
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ACKNOWLEDGEMENTS

I would like to thank my research advisor Dr. Mark T. Holtzapple for his
guidance, supervision, and support for this research. Our conversations and brain
storming sessions have generated projects we call the ‘wild cats.’ These ‘wild cats’
were investigated at the laboratory, some were successful, others were not. I would also
like to thank Dr. Richard R. Davison for his interest in our research and for visiting our
laboratory frequently to see if I got any new data. I had very useful discussions and
learnt a lot from him. I would like to thank Dr. Mahmoud M. El-Halwagi who taught
me process integration and made me always think of what will happen to the entire
process when making changes in even a small part of the MixAlco process. His wise
counsel has been of great help. I want to thank Dr. Cady Engler who taught me
bioreactor design and has been helpful in providing useful insights and suggestions for
my research. I want to thank Dr. Theresa Good for recommending me for admission and
Dr. Christine Grant for getting me interested in environmentally related research.
I also like to thank the engineering technicians, Randy Marek and Nathan
Okonski, for their assistance in making the fermentors and teaching me how to use the
machines. I am indebted to my past group members Cateryna Aiello-Mazzarri, Sehoon
Kim, Piyarat Thanakoses, Wen-Ning Chan, Guillermo Coward-Kelly, Cesar Granda,
and Xu Li for their assistance. Thanks to my present group members Zhihong Fu,
Jonathan O’Dwyer, Li Zhu, Maxine Jones, Rocio Sierra, and Stanley Coleman.
Finally, I like to thank the student workers who helped me to do the
fermentations as well as the great secretaries at the Department of Chemical
Engineering who were always ready to help.
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TABLE OF CONTENTS
Page
ABSTRACT........................................................................................................... iii
ACKNOWLEDGEMENTS................................................................................... v
TABLE OF CONTENTS....................................................................................... vi
LIST OF TABLES................................................................................................. ix
LIST OF FIGURES................................................................................................ x
CHAPTER I INTRODUCTION............................................................................ 1
1.1 Biomass as a Sustainable Fuel and Chemical Source.......................... 1
1.2 Components of Cellulosic Biomass..................................................... 2
1.3 Biomass Pretreatment........................................................................... 5
1.4 Lime Pretreatment................................................................................ 5
1.5 Rice Straw Conversion Technologies.................................................. 6
1.6 The MixAlco Process........................................................................... 7
1.7 Countercurrent Fermentation and CPDM............................................ 10
1.8 Fixed-bed Fermentation....................................................................... 12
1.9 Lignin Degradation.............................................................................. 13
1.10 Buffer................................................................................................. 13
1.11 Ash Pretreatment................................................................................ 15
CHAPTER II MATERIALS AND METHODS.................................................... 16
2.1 Substrates............................................................................................. 16
2.2 Media and Nutrients............................................................................. 16
2.3 Inoculum............................................................................................... 17
2.4 Inhibitor................................................................................................ 17
2.5 Fermentors............................................................................................ 17
2.6 Analytical Methods.............................................................................. 21
2.7 Mass Balance........................................................................................ 22
2.8 Continuum Particle Distribution Model (CPDM)................................ 23
2.9 Statistical Methods............................................................................... 29
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Page
CHAPTER III RICE STRAW COUNTERCURRENT FERMENTATION......... 30
3.1 Fermentation Conditions...................................................................... 30
3.2 Model Development............................................................................. 46
3.3 Conclusion............................................................................................ 53
CHAPTER IV FIXED-BED FERMENTATION.................................................. 54
4.1 Fermentation Trains A and B............................................................... 55
4.2 Fermentation Trains C and D............................................................... 60
4.3 Modeling Fixed-bed Fermentation....................................................... 64
4.4 The Round Robin System.................................................................... 79
4.5 Conclusion............................................................................................ 85
CHAPTER V USING ASH TO PRETREAT BIOMASS..................................... 87
5.1 Poplar Wood......................................................................................... 87
5.2 Bagasse................................................................................................. 91
5.3 Conclusion............................................................................................ 93
CHAPTER VI LIGNIN FERMENTATION.......................................................... 94
6.1 Poplar Wood......................................................................................... 94
6.2 Bagasse................................................................................................. 99
6.3 Conclusion............................................................................................ 101
CHAPTER VII USING AMMONIUM BICARBONATE AS A BUFFER
COMPARED TO CALCIUM CARBONATE............................. 103
7.1 Experiment 1........................................................................................ 103
7.2 Experiment 2........................................................................................ 105
7.3 Experiment 3........................................................................................ 109
7.4 Conclusion............................................................................................ 111
CHAPTER VIII CONCLUSIONS AND RECOMMENDATIONS..................... 112
REFERENCES....................................................................................................... 116
APPENDIX A........................................................................................................ 122
APPENDIX B........................................................................................................ 123
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Page
APPENDIX C........................................................................................................ 124
APPENDIX D........................................................................................................ 125
APPENDIX E......................................................................................................... 126
APPENDIX F......................................................................................................... 128
APPENDIX G........................................................................................................ 131
APPENDIX H........................................................................................................ 134
APPENDIX I.......................................................................................................... 135
APPENDIX J.......................................................................................................... 139
APPENDIX K........................................................................................................ 144
APPENDIX L......................................................................................................... 147
APPENDIX M........................................................................................................ 149
APPENDIX N........................................................................................................ 150
VITA...................................................................................................................... 209
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LIST OF TABLES
Page
Table 3-1. Operating parameters for rice straw/chicken manure countercurrent
fermentation with marine inoculum..................................................... 38
Table 3-2. Results for rice straw/chicken manure countercurrent fermentation
with marine inoculum........................................................................... 39
Table 3-3. The values of a, b, c in CPDM for rice straw/chicken manure
fermentation......................................................................................... 49
Table 3-4. Parameter values in CPDM for rice straw/chicken manure
fermentation......................................................................................... 50
Table 3-5. Comparison of experimental and predicted carboxylic acid
concentration and substrate conversion for rice straw/chicken
manure fermentation............................................................................ 51
Table 4-1. Pretreatment conditions........................................................................ 55
Table 4-2. Fermentation results for Train A.......................................................... 58
Table 4-3. Fermentation results for Train B........................................................... 59
Table 4-4. Fermentation results for Train C........................................................... 62
Table 4-5. Fermentation results for Train D.......................................................... 63
Table 6-1. Composition of original poplar wood and residue................................ 95
Table 6-2. Composition of original bagasse and residue....................................... 99
Table 6-3. Components in the fermentors.............................................................. 100
x
LIST OF FIGURES
Page
Figure 1-1. (a) Conformal form of cellulose (b) Cellulose microfibril.................. 3
Figure 1-2. Lignin monomers................................................................................. 4
Figure 1-3. Ultrastructural organization of cell wall components......................... 5
Figure 1-4. MixAlco process.................................................................................. 7
Figure 1-5. Major fermentation pathway in the rumen.......................................... 9
Figure 1-6. The digestion of biomass..................................................................... 10
Figure 1-7. Four-stage countercurrent fermentation.............................................. 11
Figure 1-8. Liquid transfer in fixed-bed fermentor................................................ 12
Figure 1-9. Titration curve for organic acids......................................................... 15
Figure 2-1. Centrifuge bottle bioreactor................................................................. 18
Figure 2-2. Fixed-bed fermentor............................................................................ 19
Figure 2-3. Jacketed fermentor system.................................................................. 20
Figure 2-4. Water displacement apparatus............................................................. 21
Figure 2-5. ‘Round robin’ fermentation system..................................................... 29
Figure 3-1. Total acid concentration from F1 in Train A....................................... 32
Figure 3-2. Total acid concentration from F1 in Train B....................................... 33
Figure 3-3. Total acid concentration from F1 in Train C....................................... 34
Figure 3-4. Total acid concentration from F1 in Train D....................................... 35
Figure 3-5. Total acid concentration from F1 in Train E....................................... 36
Figure 3-6. Total acid concentration from F1 in Train F....................................... 37
Figure 3-7. Correlation of total acid productivity with volatile solid loading
rate...................................................................................................... 41
Figure 3-8. Correlation of yield with volatile solid loading rate............................ 41
Figure 3-9. Correlation of selectivity with volatile solid loading rate................... 42
Figure 3-10. Correlation of conversion with volatile solid loading rate................ 42
Figure 3-11. Mass balance in Train A.................................................................... 43