Biohydrogen Production by Modified Anaerobic Fluidized Bed Reactor

121 Pages·2008·2.7 MB·English

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Islamic university (cid:150)Gaza
Faculty of science.
Research and Graduate Affairs.
Biological Sciences.

Biohydrogen Production by Modified Anaerobic Fluidized Bed
Reactor (AFBR) Using Mixed Bacterial Cultures in Thermophilic
Condition.

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BY
Amani Abu Rahma

Supervisors
 Dr. Kamal El-Kahlout Dr.Tarek El-Bashiti
Assistant Professor in Biotechnology Associate Professor in Biotechnology


A thesis submitted to the Faculty of Science, in fulfilment for the Degree of Master of
Biological Sciences.

2013-1435
ACKNOWLEDGEMENTS
First and most of all, I would like to express my sincere appreciation and
indebtedness to my supervisors, Dr. Kamal El Kahlout and Dr.Tareq El Bachiti , whose
valuable guidance and support, spiritual encouragement and patience contributed much to
the successful completion of my study. Besides, a great thank goes to Professor: Nizam El
Ashqar for his suggestions and great help.
I would also like to express my gratitude to many specialists who helped with my
laboratory work: Dr. Mohammed Abo Oda, Mahmoud El Hindi, and Basem Qshta, who
helped with my laboratory work.
Finally, I truly thank my family and friends for their support and encouragement. A
very special thank-you should go to my father, my children, and my brother Basel, who
supported my work financially and tried his best to cheer me up when I was in low spirits.















i
List of Content
Acknowledgments i
Abstract 1
ΔλϼΨϟ΍ 
Chapter . Introduction. 
I
1.1-overview. 3
1.2-General objective. 
1.3-Speciefic objective. 
1.4-Significance. 
Chapter . Litreture review. 
II
2.1-The energy challenge. 
2.2-Hydrogen as energy carrier. 
2.3-Energy and air pollution profile in Palestine. 
2.4-Hydrogen production. 
2.5-Biological production technologies. 
2.5.1-Photofermentation. 
 2.5.2-Hydrogen dark fermentation. 
 2.5.2.1-Hydrolysis. 
 2.5.2.2-Acidogenesis. 
2.5.2.3-Acetogenesis. 
 2.5.2.4-Methanogenesis. 
2.6- Biochemical pathways of hydrogen fermentation. 
2.7-Electron flow model. 
2.8-Hydrogenases. 
2.9-Thermodynamics of hydrogen formation. 
2.10-Microorganisms used in hydrogen dark fermentation and their yields. 
2.11- Factors affecting dark fermentive hydrogen production. 
 2.11.1-Tempreture. 
2.11.2-pH. 
2.11.3- Hydrogen partial pressure. 
ii
 2.11.4- Carbon dioxide partial pressure. 
 2.11.5- Organic acid concentration. 
2.11.6-Inorganic elements. 
 2.11.7-Iron concentration. 
 2.11.8-C/N ratio. 
2.12-Operation strategies. 
 2.12.1-Batch and semicontinous process. 
 2.12.2-Continuous stirred tank reactor. 
2.12.3-Membrane bioreactor. 
 2.12.4- Immobilized cell process and methods. 
2.13-Bioreactor type. 
 2.13.1-Fixed bed reactor. 
2.13.2- Fluidized bed reactor. 
 2.13.3- UASB Reactor. 
 2.13.3-CSTR granular sludge reactor. 
2.14-Optimization of hydrogen production by bioprocess engineering. 
2.14.1-Mass transfer. 
2.14.2-Biomass retention. 
2.14.3-Granulation. 
 2.14.4-Biofilms. 
2.14.5-Gas separation. 
2.15-Hybrid process. 
Chapter III. Material and methods. ϱϮ
3.1- Materials 
 3.1.1-Bioreactor nutrient medium formulation. 
3.1.2-- Inoculum collection. 
3.2- methods. 
 3.2.1-Inoculum preparation. 
 3.2.2-Bioreactor design and setup. 
3.2.3-Operation strategy.
ϱϰ
iii
3.3- Analytical techniques.
ϱϲ
3.3.1-Gas analysis.
ϱϲ
3.3.2-Volatile fatty acid analysis.
ϱϳ
3.3.3-Sucrose determination.
ϱϳ
 3.3.4-Total bacterial biomass determination. ϱϴ
Chapter . Results. 
IV
4.1-Bioreactor set up and design. 
4.2-Granule growth. 
4.3-Thermophilic bioreactor performance. 
Chapter V. Discussion. 
5.1-Bioreactor design and strategy. 
5.2- Effect of thermophilic temperature, HRT, and effluent recycle rate on

hydrogen yield and productivity.
5.3- microbial growth and induction of granulation. 
5.4- Assessment of gas disengagement. 
5.5- Effect of total bioreactor volume on biohydrogen yield and production. 
5.6- A Relationship between hydrogen and soluble metabolite. 
5.7- A relationship between pH and soluble metabolites. 
5.8-Synotrophic microcology model and VFAs. 
Chapter VI. Conclusion and Further suggestions 
6.1-Conclusion 
6.2-Further suggestions. 
References. 
Appendices. 
iv
List of tables
.
Table 2.2: Basic Properties of Hydrogen, Methane, and Propane 
Table 2.9- Reaction Stoichiometries of Dark Fermentation of Glucose 
Table 2.11- Main Factors Affecting Bioydrogen Production. 
Table 2.12- Main fermentation processes used in dark hydrogen 
fermentations and some of their benefits and draw backs.
Table 2.14.2- Cell retainment strategies applied for dark fermentative H2 
production.
Table 2.14.3- Factors affecting granulation. 
Table 2.15a- Hydrogen production with processes combining dark and 
photofermentation
Table 2.15b- Performance of mixed- culture processes combining 
hydrogen dark fermentation and methanogenesis.
Table 4.3.1- Thermophilic bioreactor performance with respect to 
hudrogen production rate, hydrogen productivity and hydrogen yield,
during 24 days of operation.
Table 4. 3.2- Thermophilic bioreactor performance with respect to: 
Sucrose conversion rate, distribution of soluble metabolites, during 24 days
of operation.
Table 4.3.3-Thermophilic bioreactor performance with respect sucrose 
conversion.
Table 4.3.4-Thermophilic bioreactor performance with respect to total 
bioreactor volume and recycle rate.
Table 5.2- Summary of Bioreactor operation and performance data for 
different high performance AFGB Systems.
v
List of figures

Figure 2.1- A schematic illustration of the greenhouse effect. 
Figure 2.5.2- Different stages of anaerobic digestion of organic matter and 
the microbial groups involved.
Figure 2.6- Catabolic pathways of mixed-acid fermentation from glucose. 
Figure 2.7- Schematic diagram of the electron-flow model. 
Figure 3.2.2- Modified AFGB system. Diagram labels 
Figure 4.1 - Modified AFGB system installed. 
Figure4.2- Bacterial granules in the bioreactor. 
Figure 4.3.1- Effect of effluent recycle rate on hydrogen production rate. 
Figure 4.3.2- Effect of effluent recycle rate on hydrogen yield. 
Figure 4.3.3- Effect of effluent recycle rate on hydrogen productivity. 
Figure 4.3.4- Effect of effluent recycle rate on hydrogen content. 
Figure 4.3.5- Effect of HRT on hydrogen production rate. 
Figure 4.3.6- Effect of HRT on hydrogen yield. 
Figure 4.3.7- Effect of HRT on hydrogen productivity. 
Figure 4.3.8- Effect of HRT on hydrogen content. 
Figure 4.3.9- Effect of HRT on hydrogen production rate and substrate 
conversion.
Figure 4.3.10- Time course profile of the pH in AFBR. 
Figure 4.3.11-the relationship between pH and hydrogen production rate 
during operational course.
Figure 4.3.12- Distribution of soluble metabolites with respect to HRT. 
Figure 4.3.13- Relationship between V/Fer and hydrogen yield. 
Figure 5.4-The partitioning of non-dissolved and soluble H between the 
2
three different phases in the AFGB system.
vi
List of Abbreviations
AFBR Anaerobic fluidized bed bioreactor.
AFGB Anaerobic fluidized granular bioreactor
ASBR Anaerobic sequencing batch reactor .
CAC Cylindrical activated carbon.
AC Activated carbon.
COD Chemical oxygen demand.
CSTR Continuous [flow] stirred tank reactor.
CIGSB Carrier induced granular sludge bed bioreactor.
EAMC Electrochemically assisted microbial cell
GAC Granular activated carbon.
GHG Green house gases.
HRT Hydraulic retention time.
1 1
HPR Hydrogen production rate (mmol h L ).
HP Hydrogen productivity.
1
HY Hydrogen yield mol-H2 mol-electron donor
ICSAB Immobilized (cid:150) cell- seeded anaerobic bioreactor.
MBR Membrane bioreactor.
MDGs Millennium Development Goals.

NAD Nicotinamideadenine dinucleotide (oxidized form).
NADH Nicotinamideadenine dinucleotide (reduced form).
PBR Packed- bed reactor.
vii
ppm Part per million.
ppp Pentose phosphate pathway.
PSII Photosystem II (or water-plastoquinone oxidoreductase).
æH2 Partial pressure of hydrogen.
SRT Sludge retention time.
CIGSB Carrier-induced granular sludge bed bioreactor.
TBR Tricking biofilter reactor.
T Temperature (k).
OLR Organic loading rate.
UASB Upflow anaerobic sludge blanket.
VFA Volatile fatty acids.
VSS Volatile suspended solids.
viii
Abstract.
Hydrogen production represents a vital foundation for a hydrogen economy.
Research, development, and demonstration, however, must continue in order to bring down
the cost, increase the efficiency, and address the emissions issues associated with hydrogen
production technologies. Dark fermentation using AFBR considered recently being
promising and highly efficient in producing hydrogen gas in quantities exceeding even the
theoretical values of 4 mol H / mol glucose if certain modification in the bioreactor
2
design and process are made.
Thermophilic fermentative biohydrogen production was studied in the anaerobic
fluidized bed reactor (AFBR) operated at 65”C with sucrose as a substrate. Theoretically,
the maximum hydrogen yield (HY) is 4 mol H /mol glucose when glucose is completely
2
metabolized to acetate, H and CO . But somehow, under most bioreactor design and
2 2
operation conditions the maximum possible hydrogen yield (HY) as generally been
observed not to exceed or reach 70-100% of the maximum theoretical hydrogen yield.
In this study further modification in anaerobic fluidized bed reactor namely the
decrease in the total liquid volume to 3.3L, in addition to the application of external work
in the form of high temperatures, high dilution rates and high rates of de-gassed effluent
recycling were investigated as a means to overcome the thermodynamic constrains
preventing the simultaneous achievement of high hydrogen yield (HY) and hydrogen
productivity (HP) in an AFBR reactor.
Bacterial granulation was successfully induced under a thermophilic temperature of
650C. The bacterial granules consisted of a multispecies bacterial consortium comprised of
thermophilic consortium . At a hydraulic retention time (HRT) of 1 h and effluent recycle
rate of 3.6 L/ min, with V/F equal to 0.91 min, hydrogen production rate (HPR) of 7.57
er
L H / h and hydrogen yield of 5.8 mol H / mol glucose were achieved. This was greater
2 2
than the yield achieved in a previous study conducted on 2012 , where the yield was 3.55
mol H / mol glucose under similar experimental conditions.
2
Key wors: Dark fermentation.Thermophilictempreture. Modified anerobic fluidized
bed reactor. Synotrophicmicrocology.
ϭ