KELVIN YORO
Supervisors: Prof. M.O. Daramola, Dr. J.L Mulopo
Address: Sustainable Energy & Environment Research Unit, Faculty of Engineering and the Built Environment, School of Chemical and Metallurgical Engineering, University of the Witwatersrand, Johannesburg 2050, South Arica;
Address: Sustainable Energy & Environment Research Unit, Faculty of Engineering and the Built Environment, School of Chemical and Metallurgical Engineering, University of the Witwatersrand, Johannesburg 2050, South Arica;
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Papers by KELVIN YORO
have fuelled the need to search for clean and
sustainable energy resources. The process of biohydrogen has been highlighted as a propitious alternative
energy of the future because it has many socioeconomic benefits such as non-polluting features, the
ability to use diverse feedstocks including waste
materials, the process uses various microorganisms,
and it is the simplest method of producing hydrogen.
However, the establishment of a biohydrogen driven
economy has been hindered by low process yields due
to the accumulation of inhibitory products. Over the
past few years, various optimization methods have
been used in literature. Among these, integration of
bioprocesses is gaining increasing prominence as an
effective approach that could be used to achieve a
theoretical yield of 4 mol H2 mol-1 glucose. In batch
integrated systems, dark fermentation is used as a
primary process for conversion of substrates into
biohydrogen, carbon dioxide, and volatile fatty acids.
This is followed by a secondary anaerobic process for
further biohydrogen conversion efficiency. This
review discusses the current challenges facing scaleup studies in dark fermentation process. It elucidates
the potential of batch integrated systems in biohydrogen process development. Furthermore, it explores the
various integrated fermentation techniques that are
employed in biohydrogen process development.
Finally, the review concludes with recommendations
on improvement of these integrated processes for
enhanced biohydrogen yields which could pave a way
for the establishment of a large-scale biohydrogen
production process.
operating conditions (e.g. pressure, temperature and gas flow rates) as well as the effect of moisture on the adsorption
capacity of polyaspartamide were methodically investigated using Dubinin–Raduskevich model. Results from the investigations reveal that the presence of moisture in the flue gas had an incremental effect on the adsorption capacity of
polyaspartamide; thereby showcasing the potential of polyaspartamide as a suitable hydrophilic material for CO2 capture in
power plants. In addition, pressure, temperature and gas flow rates at 200 kPa, 403 K, and 1.5 mL/s, respectively, significantly influenced the CO2 adsorption capacity of polyaspartamide. Physisorption and chemisorption both governed the
adsorption process while equilibrium studies at different temperatures showed that Langmuir isotherm could adequately
describe the adsorption behaviour of the material with best fit with R2[ 0.95.
carbon in a continuous packed bed column for the removal of
dibenzothiophene (DBT) from petroleum distillates is reported.
Model diesel containing only DBT was desulfurized by
adsorption using activated carbon as an adsorbent in
continuous mode. Scanning electron microscope (SEM)
equipped with energy dispersive X-ray (EDX) was used to
check the morphology and elemental compositions of the
adsorbent. Surface chemical functionalities were checked using
Fourier transform infra-red (FTIR) spectroscopy. The results
show that about 16 mg kg-1 adsorption capacity of the
adsorbent for adsorbate at 3 ml min-1and adsorbent amount of
2.0 g. In addition, the adsorption the adsorption behavior of
the adsorbent could be perfectly described with Langmuir
isotherm model. The kinetics of the adsorption could be
described well using Bohart Adams and Thomas models.
focus on heat exchanger network synthesis. Reports on mass
exchanger network synthesis mostly discussed singlecomponent problems using simultaneous approaches.
However, less attention has been given to mass exchanger
network synthesis with multi-component problems using the
sequential technique. Till date, it has not been easy to
systematically choose between the process and available
external mass separating agents (MSA) in mass exchanger
network synthesis during the adsorption of CO2. In this paper,
we set out a technique for targeting external mass separating
agent and its network design. The technique was applied to a
CO2 adsorption process involving two mass separating agents
(process and external MSAs) that overlap. A thermodynamic
analysis of the CO2 adsorption process was outlined in this
study using the composition interval method. Feasible
structures were formulated and the synthesis task was
expressed in a two-stage targeting procedure as an
optimization task. Unlike previous studies reported in the past
for mass exchanger network synthesis, this contribution
considers a trade-off between the process MSA S1 and external
MSA S2 to determine the minimum amount of external MSA
required for the CO2 capture process. A case study was
adapted from open literature to demonstrate the effectiveness
of the synthesized mass exchanger network during a typical
CO2 capture process. Outcomes from this study indicate that
mass integration via process synthesis is an effective strategy
that can minimize the quantity of external utilities required
during the adsorption of CO2 from a rich stream of flue gas.
Keywords: Biohydrogen, cell immobilization, process parameters, microorganisms