Abstract: The paper describes the experiments and the kinetic
parameters calculus of the gasoil hydrofining. They are presented
experimental results of gasoil hidrofining using Mo and promoted
with Ni on aluminum support catalyst. The authors have adapted a
kinetic model gasoil hydrofining. Using this proposed kinetic model
and the experimental data they have calculated the parameters of the
model. The numerical calculus is based on minimizing the difference
between the experimental sulf concentration and kinetic model
estimation.
Abstract: The aluminum impregnated catalysts of Al-alumina (Al-Al2O3), Al-montmorillonite (Al-Mmn) and Al-activated charcoal (Al-AC) of various percent loadings were prepared by wet impregnation method and characterized by SEM, XRD and N2 adsorption/desorption (BET). The catalytic properties were investigated in the degradation of waste polystyrene (WPS). The results of catalytic degradation of Al metal, 20% Al-Al2O3, 5% Al-Mmn and 20% Al-AC were compared with each other for optimum conditions. Among the catalyst used 20% Al-Al2O3 was found the most effective catalyst. The BET surface area of 20% Al-Al2O3 determined was 70.2 m2/g. The SEM data revealed the catalyst with porous structure throughout the frame work with small nanosized crystallites. The yield of liquid products with 20% Al-Al2O3 (91.53 ± 2.27 wt%) was the same as compared to Al metal (91.20 ± 0.35 wt%) but the selectivity of hydrocarbons and yield of styrene monomer (56.32 wt%) was higher with 20% Al-Al2O3 catalyst.
Abstract: Depletion and hazardous gas emissions associated
with fossil fuels have caused scientists and global attention to focus
on the use of “alternative, eco-friendly substitutes for use in
Compression Ignition Engines. In this work, biodiesel was produced
by trans-esterification of soybean obtained from a Nigerian market
using Sodium Hydroxide (NaOH) as a catalyst.” After the
production, the physical properties (specific gravity to kinematic
viscosity and net calorific value) of the Soybean-biodiesel produced
and petrol diesel obtained from a filling station in Nigeria were
determined, and these properties conform to conventional standards
(ASTM). A cummins-6V-92TA DDEC diesel (Compression ignition,
CI) engine was run on various biodiesel-petrol diesel blends (0/100,
10/90, 20/80, 30/70 and 40/60), the B20 (blend 20/80) was found to
be the most satisfactory.
Abstract: In this study, fish bone waste was used as a new
catalyst for biodiesel production. Instead of discarding the fish bone
waste, it will be utilized as a source for catalyst that can provide
significant benefit to the environment. Also, it can be substitute as a
calcium oxide source instead of using eggshell, crab shell and snail
shell. The XRD and SEM analysis proved that calcined fish bone
contains calcium oxide, calcium phosphate and hydroxyapatite. The
catalyst was characterized using Scanning Electron Microscope
(SEM) and X-ray Diffraction (XRD).
Abstract: Biopolymers have gained much attention as ecofriendly alternatives to petrochemical-based plastics because they are biodegradable and can be produced from renewable feedstocks. One class of biopolyester with many potential environmentally
friendly applications is polylactic acid (PLA) and polycaprolactone (PCL). The PLA/PCL biodegradable copolyesters were synthesized by bulk ring-opening copolymerization of successively added Llactide (LL) and ε-caprolactone (CL) in the presence of toluene, using 1-hexanol as initiator and stannous octoate (Sn(Oct)2) as catalyst. Reaction temperature, reaction time and amount of catalyst were evaluated to obtain optimum reaction conditions. The results showed that the %conversion increased with increases in reaction temperature and reaction time, but after a critical amount of catalyst was reached the %conversion decreased. The yield of PLA/PCL biopolymer achieved 98.02% at the reaction temperature 160 °C, amount of catalyst 0.3 mol% and reaction time of 48 h. In addition, the thermal properties of the product were determined by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).
Abstract: The present investigation deals with bioleaching of spent petroleum catalyst using At. ferrooxidans and At. thiooxidans. The spent catalyst used in the present study was pretreated with acetone to remove the oily hydrocarbons. FESEM and XPS analysis indicated the presence of metals in sulfide and oxide forms in spent catalyst. Both At. ferrooxidans and At. thiooxidans were found to be highly effective in producing the acid. Bioleaching with At. ferrooxidans and At. thiooxidans led to higher recovery of metals compare to control. During bioleaching similar recoveries of metals were obtained using At. ferrooxidans and At. thiooxidans. This might be due to the presence of metals as soluble oxides and sulphides in the spent catalyst. At the end of bioleaching, about 87-90% Ni, 34% Al, 65-73% Mo and 92-97% V were leached using above bacteria. It is elucidated that bioleaching with At. thiooxidans is comparatively more advantageous due to lower cost of sulphur.
Abstract: Recently, a growing interest has emerged on the development of new and efficient energy sources, due to the inevitable extinction of the nonrenewable energy reserves. One of these alternative sources which have a great potential and sustainability to meet up the energy demand is biomass energy. This significant energy source can be utilized with various energy conversion technologies, one of which is biomass gasification in supercritical water.
Water, being the most important solvent in nature, has very important characteristics as a reaction solvent under supercritical circumstances. At temperatures above its critical point (374.8oC and 22.1MPa), water becomes more acidic and its diffusivity increases. Working with water at high temperatures increases the thermal reaction rate, which in consequence leads to a better dissolving of the organic matters and a fast reaction with oxygen. Hence, supercritical water offers a control mechanism depending on solubility, excellent transport properties based on its high diffusion ability and new reaction possibilities for hydrolysis or oxidation.
In this study the gasification of a real biomass, namely olive mill wastewater (OMW), in supercritical water conditions is investigated with the use of Ru/Al2O3 catalyst. OMW is a by-product obtained during olive oil production, which has a complex nature characterized by a high content of organic compounds and polyphenols. These properties impose OMW a significant pollution potential, but at the same time, the high content of organics makes OMW a desirable biomass candidate for energy production.
The catalytic gasification experiments were made with five different reaction temperatures (400, 450, 500, 550 and 600°C) and five reaction times (30, 60, 90, 120 and 150s), under a constant pressure of 25MPa. Through these experiments, the effects of reaction temperature and time on the gasification yield, gaseous product composition and OMW treatment efficiency were investigated.
Abstract: Transesterification reactions free of catalyst between
roasted chicken fat with methanol were carried out in a batch reactor
in order to produce biodiesel to temperatures from 120°C to 140°C.
Parameters related to the transesterification reactions, including
temperature, time and the molar ratio of chicken fat to methanol also
investigated. The maximum yield of the reaction was of 98% under
conditions of 140°C, 4 h of reaction time and a molar ratio of chicken
fat to methanol of 1:31. The biodiesel thus obtained exhibited a
viscosity of 6.3 mm2/s and a density of 895.9 kg/m3. The results
showed this process can be right choice to produce biodiesel since
this process does not use any catalyst. Therefore, the steps of
neutralization and washing are avoided, indispensables in the case of
the alkaline catalysis.
Abstract: Combustion of fuels in industrial and transport sector has lead to an alarming release of polluting gases to the atmosphere. Carbon monoxide is one such pollutant, which is formed as a result of incomplete oxidation of the fuel. In order to analyze the effect of catalyst on the reduction of CO emissions to the atmosphere, two catalysts Mn2O3 and Hopcalite are considered. A model was formed based on mass and energy balance equations. Results show that Hopcalite catalyst as compared to Mn2O3 catalyst helped in faster conversion of the polluting gas as the operating temperature of the hopcalite catalyst is much lower as compared to the operating temperature of Mn2O3 catalyst.
Abstract: The production of biodiesel from crude palm oil with
a homogeneous base catalyst is unlikely owing to considerable
formation of soap. Free fatty acids (FFA) in crude palm oil need to
be reduced, e.g. by esterification. This study investigated the activity
of sulfated zirconia calcined at various temperatures for esterification
of FFA in crude palm oil to biodiesel. It was found that under a
proper reaction condition, sulfated zirconia well catalyzes
esterification. FFA content can be reduced to an acceptable value for
typical biodiesel production with a homogeneous base catalyst.
Crystallinity and sulfate attachment of sulfated zirconia depend on
calcination temperature during the catalyst preparation. Too low
temperature of calcination gives amorphous sulfated zirconia which
has low activity for esterification of FFA. In contrast, very high
temperature of calcination removes sulfate group, consequently,
conversion of FFA is reduced. The appropriate temperature range of
calcination is 550-650 oC.
Abstract: Selective oxidation of H2S to elemental sulfur in a
fixed bed reactor over newly synthesized alumina nanocatalysts was
physio-chemically investigated and results compared with a
commercial Claus catalyst. Amongst these new materials, Al2O3-
supported sodium oxide prepared with wet chemical technique and
Al2O3 nanocatalyst prepared with spray pyrolysis method were the
most active catalysts for selective oxidation of H2S to elemental
sulfur. Other prepared nanocatalysts were quickly deactivated,
mainly due to the interaction with H2S and conversion into sulfides.
Abstract: In order to meet environmental norms, Indian fuel
policy aims at producing ultra low sulphur diesel (ULSD) in near
future. A catalyst for meeting such requirements has been developed
and kinetics of this catalytic process is being looked into. In the
present investigations, effect of mass transfer on kinetics of ultra deep
hydrodesulphurization (UDHDS) to produce ULSD has been studied
to determine intrinsic kinetics over a pre-sulphided catalyst.
Experiments have been carried out in a continuous flow micro reactor
operated in the temperature range of 330 to 3600C, whsv of 1 hr-1 at a
pressure of 35 bar, and its parameters estimated. Based on the derived
rate expression and estimated parameters optimum operation range
has been determined for this UDHDS catalyst to obtain ULSD
product.
Abstract: The influence of copper promoters and reaction
conditions on the formation of alcohols byproducts of a common
Fischer-Tropsch synthesis used iron-based catalysts were investigated.
A good compromise of 28%Cu/FeKLaSiO2 can lead to the
optimization of an improved Fischer-Tropsch catalyst. The product
distribution shifts towards hydrocarbons with increasing the reaction
temperature, while pressure promotes the formation of alcohols. It was
found that the production of either alcohols or hydrocarbons followed
A-S-F distributions, and their α parameters were essentially different
which indicated a competition in the growing chain between the two
species. TPD after acetaldehyde adsorption gave strong evidence of
the insertion of a C1 oxygen-containing species into an alkyl chain.
Abstract: We investigated a modified thermal evaporation
method in the growth process of ZnO nanowires. ZnO nanowires
were fabricated on p-type silicon substrates without using a metal
catalyst. A simple horizontal double-tube system along with
chemical vapor diffusion of the precursor was used to grow the ZnO
nanowires. The substrates were placed in different temperature
zones, and ZnO nanowires with different diameters were obtained for
the different substrate temperatures. In addition to the nanowires,
ZnO microdiscs with different diameters were obtained on another
substrate, which was placed at a lower temperature than the other
substrates. The optical properties and crystalline quality of the ZnO
nanowires and microdiscs were characterized by room temperature
photoluminescence (PL) and Raman spectrometers. The PL and
Raman studies demonstrated that the ZnO nanowires and microdiscs
grown using such set-up had good crystallinity with excellent optical
properties. Rectifying behavior of ZnO/Si heterostructures was
characterized by a simple DC circuit.
Abstract: Thermodynamics characterization Sesame oil
extraction by Acetone, Hexane and Benzene has been evaluated. The
120 hours experimental Data were described by a simple
mathematical model. According to the simulation results and the
essential criteria, Acetone is superior to other solvents but under
certain conditions where oil extraction takes place Hexane is superior
catalyst.
Abstract: High purity hydrogen and the valuable by-product of carbon nanotubes (CNTs) can be produced by the methane catalytic decomposition. The methane conversion and the performance of CNTs were determined by the choices of catalysts and the condition of decomposition reaction. In this paper, Ni/MgO and Ni/O-D (oxidized diamond) catalysts were prepared by wetness impregnation method. The effects of reaction temperature and space velocity of methane on the methane conversion were investigated in a fixed-bed. The surface area, structure and micrography were characterized with BET, XPS, SEM, EDS technology. The results showed that the conversion of methane was above 8% within 150 min (T=500) for 33Ni/O-D catalyst and higher than 25% within 120 min (T=650) for 41Ni/MgO catalyst. The initial conversion increased with the increasing temperature of the decomposition reaction, but their catalytic activities decreased rapidly while at too higher temperature. To decrease the space velocity of methane was propitious to promote the methane conversion, but not favor of the hydrogen yields. The appearance of carbon resulted from the methane decomposition lied on the support type and the condition of catalytic reaction. It presented as fiber shape on the surface of Ni/O-D at the relatively lower temperature such as 500 and 550, but as grain shape stacked on and overlayed on the surface of the metal nickel while at 650. The carbon fiber can form on the Ni/MgO surface at 650 and the diameter of the carbon fiber increased with the decreasing space velocity.
Abstract: IFP Group Technology “Sulfrex process" was used in
Iran-s South Pars Gas Complex Refineries for removing sulfur
compounds such as mercaptans, carbonyl sulfide and hydrogen
sulfide, which uses sulfonated cobalt phthalocyanine dispersed in
alkaline solution as catalyst. In this technology, catalyst and alkaline
solution were used circularly. However the stability of catalyst due to
effect of some parameters would reduce with the running of the unit
and therefore sweetening efficiency would be decreased. Hence, the
aim of this research is study the factors effecting on the stability of
catalyst.
Abstract: Curing of paints by exposure to UV radiations is
emerging as one of the best film forming technique as an alternative
to traditional solvent borne oxidative and thermal curing coatings.
The composition and chemistry of UV curable coatings and role of
multifunctional and monofunctional monomers, oligomers, and
photoinitiators have been discussed. The limitations imposed by
thermodynamic equilibrium and tendency for acrylic double bond
polymerizations during synthesis of multifunctional acrylates have
been presented. Aim of present investigation was thus to explore the
reaction variables associated with synthesis of multifunctional
acrylates. Zirconium oxychloride was evaluated as catalyst against
regular acid functional catalyst. The catalyzed synthesis of glyceryl
acrylate and neopentyl glycol acrylate was conducted by variation of
following reaction parameters: two different reactant molar ratios-
1:4 and 1:6; catalyst usage in % by moles on polyol- 2.5, 5.0 and 7.5
and two different reaction temperatures- 45 and 75 0C. The reaction
was monitored by determination of acid value and hydroxy value at
regular intervals, besides TLC, HPLC, and FTIR analysis of
intermediates and products. On the basis of determination of reaction
progress over 1-60 hrs, the esterification reaction was observed to
follow 2nd order kinetics with rate constant varying from 1*10-4 to
7*10-4. The thermal and catalytic components of second order rate
constant and energy of activation were also determined. Uses of
these kinetic and thermodynamic parameters in design of reactor for
manufacture of multifunctional acrylate ester have been presented.
The synthesized multifunctional acrylates were used to formulate and
apply UV curable clear coat followed by determination of curing
characteristics and mechanical properties of cured film. The overall
curing rates less than 05 min. were easily attained indicating
economical viability of radiation curable system due to faster
production schedules
Abstract: The 9/11 suicide attacks in New York, Washington, D.C., and Pennsylvania, triggered a number of security responses both in the United States of America and other Countries in the World. Kenya, which is an ally and a close partner to North America and Europe, was not left behind. While many states had been parties to numerous terrorism conventions, their response in implementing them had been slow and needed this catalyst. This special case offered a window of opportunity for many “security conscious" regimes in cementing their legal-criminological and political security apparatus. At the international level, the 9/11 case led to the hasty adoption of Security Council resolution 1373 in 2001, which called upon states to adopt wide-ranging and comprehensive steps and strategies to combat international terrorism and to become parties to the relevant international conventions and protocols relating to terrorism. Since then, Kenya has responded with speed in devising social-legal-criminological-political actions.
Abstract: In our recent study, we have used ZnO nanoparticles assisted with UV light irradiation to investigate the photocatalytic degradation of Phenol Red (PR). The ZnO photocatalyst was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), specific surface area analysis (BET) and UVvisible spectroscopy. X-ray diffractometry result for the ZnO nanoparticles exhibit normal crystalline phase features. All observed peaks can be indexed to the pure hexagonal wurtzite crystal structures, with the space group of P63mc. There are no other impurities in the diffraction peak. In addition, TEM measurement shows that most of the nanoparticles are rod-like and spherical in shape and fairly monodispersed. A significant degradation of the PR was observed when the catalyst was added into the solution even without the UV light exposure. In addition, the photodegradation increases with the photocatalyst loading. The surface area of the ZnO nanomaterials from the BET measurement was 11.9 m2/g. Besides the photocatalyst loading, the effect of some parameters on the photodegradation efficiency such as initial PR concentration and pH were also studied.