34 research outputs found
The effect of Br- and alkali in enhancing the oxidation of furfural to maleic acid with hydrogen peroxide
This study was focused on investigating a novel catalytic system for the selective conversion of furfural to maleic
acid (MA) in an aqueous system with hydrogen peroxide as an oxidant. A series of experiments that study the
impacts of catalyst species, furfural concentration, catalyst dosage, reaction temperature, residue time, hydrogen
peroxide concentration, excess water content, and solvent types on the oxidation of furfural to MA was carried
out. The results showed that the co-existence of Br- and alkali sites might play a vital role in furfural oxidation,
which could improve the MA yield remarkably. Under 90 ◦C for 3 h, 72.4 % MA yield was obtained with KOH
and KBr as co-catalyst in an aqueous phase. Moreover, a possible reaction pathway of furfural oxidation was
proposed on the basis of our reaction system
6 ‐ Chemo‐catalytic conversion of lignin
This chapter explains catalytic chemical methods of lignin transformation which include acidcatalyzed,
base‐catalyzed and metal‐catalyzed methods. The chapter starts with a brief discussion of
the lignin architecture as a background to understanding the subsequent subject of lignin’s chemocatalytic
depolymerization methods. The general idea that lignin depolymerization involves the
cleavage of the linkages holding its basic aromatic‐based monomers is discussed. Under each of the
catalytic methods, the concept is first explained starting with the types of acid, base, or metal (as the
case may be) employed, followed by the reaction conditions and then the reaction mechanism
involved in method under discussion. Current research efforts are incorporated into each of the
sections, as obtained from recent reviews. Under the metal‐catalyzed method, reductive and
oxidative lignin depolymerization methods are explained. Extant challenges faced by lignin
researchers are mentioned in the texts. A typical laboratory procedure for lignin depolymerization
using the stainless steel autoclave is described, and the chapter ends with the future of lignin as a
viable energy source and substitute for petroleum in the manufacture of chemicals and fuels
Environment Quality in Nigeria: Implications for Poverty Reduction
Poverty in Nigeria is at extremely high levels and represents one of the
many economic hardships faced by the Nigeria population. One of the factors
potentially contributing to present high poverty levels is poor environment quality
which is prevalent in Nigeria and which may result in increased poverty levels as
efforts are undertaken to address adverse environment quality. This paper explored
the effect of environment quality on poverty reduction in Nigeria using data from
the World Bank World Development indicators over the period of 1990 to 2015.
The study employed Augmented Dickey Fuller unit root test, and Autoregressive
Distributed Lag (ARDL) estimation in analyzing data and the findings of the study
revealed that improved environment quality as measured by improved access to
sanitation and access to electricity positively and significantly increase poverty
level in Nigeria, possibly on account of the increased financial and social costs of
gaining access to sanitation and electricity. It is recommended that policy makers
ensure that policies aimed at improving environment quality in Nigeria take into
account the adverse implications of improving environment quality for poverty so
as to ensure that a balance is achieved between improved environment quality and
reduced poverty so that a cleaner environment is achieved at lower financial and
welfare cost to citizens
Topside Pipeline Design for Slug Attenuation and Increased Oil Production
In oil and gas production system, slugging is frequently
encountered when gas-liquid mixtures are transported through
a common pipeline-riser system. This phenomenon usually
manifests in significant fluctuation of flow and pressure which
can impact the production system negatively. Topside choking
is usually employed as a mitigation technique but with its
attendant reduction in production capacity. The objective of
this study therefore is to investigate the optimisation of
topside pipeline diameter and choking for effective slug
attenuation and optimised oil production.
In this paper, a new method for slug flow attenuation has been
proposed. The potential of using effective topside pipeline-
diameter design for slug flow attenuation was theoretically
shown. Numerical studies were also done to show that the
concept can indeed be adapted for effective slug attenuation
using an industrial software. Experimental studies were
conducted
in
a 4” pipeline
-riser system to validate the
numerical and theoretical studies.
The results showed that the optimised design of topside pipe
diameter has potential for slug flow attenuation at larger valve
opening which effectively translates to lower pressure and
increased oil production. For the case studied, up to
49%
reduction in the pressure drop across the topside choke valve
was reported which practically implied increased flow
capacity. An optimum volume which satisfied size, system
stability and production constraints was obtained
Biodiesel Washing Water Treatment Using Zeolite and Activated Carbon as Adsorbents
Biodiesel production was produced from the transesterification of palm oil and methanol using KOH catalyst. The process variables considered are methanol to oil mole ratio of 4 – 6 and catalyst concentration of 0.2 – 1.0 wt/wt% Oil, at constant reaction temperature of 60℃ and constant reaction time of 60 minutes. Response surface plot showed that maximum yield of biodiesel (92 %) was obtained at 0.4 wt/wt% catalyst concentration and methanol/oil mole ratio of 7. The conventional activated carbon and zeolite produced were used separately as adsorbents in the treatment of biodiesel washing water. Comparatively, zeolite produced displayed better adsorption property compared to the conventional activated carbon in removing the six heavy metals considered from the biodiesel washing water. For instance, Chromium concentration of 0.0096 mg/L was reduced to 0.0023 mg/L after adsorption treatment with activated carbon (76 % efficiency), while the concentration was reduced to 0.0010 mg/L after the adsorption treatment with zeolite (89 % efficiency)
Experimental Investigation of Hydrodynamic Slug Flow in Pipeline-Riser Systems
Activities in oil and gas industry have shifted deep offshore.
There is therefore the need to envisage and accurately provide
for flow assurance challenges that might be encountered
throughout the life of a field. Slug flow is one of the flow
assurance concerns confronting the industry. The objective of
the study was to gain insight into the behaviour of
hydrodynamic slug flow in pipeline-riser system. This
understanding is needed for the development of appropriate
slug control strategy.
Experimental studi
es were conducted in a 2”
pipeline-riser
system and a 2” horizontal two
-phase flow facility. Slug
envelopes were developed for the pipeline-riser system, the
vertical and the horizontal pipes. The results revealed three
distinct slug flow behaviours. The first type of slug was formed
in the horizontal pipeline and transported through the riser pipe
nearly unchanged, the second type of slugs were formed in the
horizontal pipe but also experience growth in the riser pipe
while the third are slugs formed in the vertical pipe without the
influence of the upstream horizontal pipe.
There is therefore the need to develop appropriate slug control
strategies based on the observed behaviour of the identified
region
Irregularly Shaped NiO Nanostructures for Catalytic Lean Methane Combustion
NiO nanomaterials prepared using a solid–liquid NH3·H2O precipitation
method (NiO-NSL) were tested in the catalytic combustion of methane.
The NiO-NSL presented a characteristic rod-like nanostructure with a
length of about a few hundred nanometers except for a part of the
nanoparticles. For comparison, the NiO nanomaterials prepared by the
traditional liquid-phase NH3·H2O precipitation method (NiO-NLL) were
tested in the same reaction conditions. NiO-NSL exhibited
significantly higher methane combustion activity than NiO-NLL and
achieved the complete combustion of methane at 390 °C, which was
outstanding in non-noble metal-based catalyst. X-ray photoelectron
spectroscopy (XPS) and hydrogen-temperature-programmed reduction
(H2-TPR) results indicate that the surface Ni2+ content of NiO-NSL
was higher than that of NiO-NLL, and the presence of more Ni2+ might
be responsible for the enhanced activity. DFT calculations prove
that the energy barrier for C–H bond activation on Ni2+ was lower
than that on Ni3+, which was consistent with the higher methane
catalytic combustion activity of NiO-NSL. In addition, when the
precipitating agent was replaced with NaOH and (NH4)2CO3, the
generalization of the solid–liquid precipitation method in the
preparation of the NiO catalysts was also tested. The results show
that the solid–liquid precipitation method proposed in this work was
still applicable when NaOH was used as a precipitant. However, with
the use of (NH4)2CO3 as a precipitant, the methane catalytic activity
of the NiO nanoparticles prepared by the solid–liquid precipitation
method was reduced to a certain extent compared with the traditional
liquid-phase precipitation method. This research can open up a
highly efficient and environmentally friendly method for the
synthesis of methane combustion catalysts
Passive Slug Attenuation Device: Potential and Operability
Over the years, there have been some concerted efforts towards developing
techniques to mitigate the threat posed by slugs to oil and gas production systems. Passive slug
attenuation devices have been known to show promising potential in this regard but can
generally be confronted with operability issues. In this study, experimental investigation on
the hydrodynamic slug attenuation potential and the operability of a process-intensified passive
slug control device- Pseudo Spiral Tube (PST) was carried out. The result showed that the
device possesses the capability to partially attenuate slug flow. This was achieved with the
help of the swirl flow generated within the device which helps achieve air entrainments in the
liquid slug leading to reduction in the effective density of the liquid slug. The results showed
that the slug severity was reduced by 24% for the case studied. However, the slug redeveloped
few meters downstream the device. Therefore, in order to achieve maximum slug attenuation,
the device should be installed immediately upstream the topside separator. It was also observed
that the pipeline might be pigged with the device installed. However, during multiphase flows,
the pig may get stuck intermittently in the device. Hence, it was conceived that a flexible pig
could be more appropriate to overcome this challenge
Investigation into Alternative Energy Sources from Waste Citrus Peel (Orange): Approach to Environmental Protection
An experimental study has been carried out on an alternative source of energy from
citrus peel waste. A widely used material, pectin, has been extracted from orange peel
(OP) and subsequently converted into ethanol with the use of a bacteria and fungi.
Dried peels were split into several particle sizes of 0.075, 0.5, 1.0 and 5 mm. It was
noted that OP with 0.75 mm particle size produced pectin of low volume while larger
1.0 mm OP particle size produced a high pectin volume. OP of 802 g was used to
produce 1,770 ml of pectin, this illustrate that citrus fruit (specifically orange) contains
pectin in a large quantity. A mixture of E.coli (bacteria) with yeast (fungus), and their
individual components were used on pectin obtained. However, it was observed that a
mixture of pectin, E.coli & S. cerevisiae, and a combination of sample pectin with
E.coli produced an encouraging volume of ethanol as against no ethanol produced
when a mixture of sample pectin, yeast and pectin sample only. The amount of energy
contained in the gross ethanol produced was 1526.6 btu, this can be combined with
purified gasoline so as to attain the optimum energy content that can be used to run an
indigenous processing plant for citrus fruit in Nigeria