Abstract: A kinetic model for propane dehydrogenation in an
industrial moving bed reactor is developed based on the reported
reaction scheme. The kinetic parameters and activity constant are
fine tuned with several sets of balanced plant data. Plant data at
different operating conditions is applied to validate the model and
the results show a good agreement between the model
predictions and plant observations in terms of the amount of main
product, propylene produced. The simulation analysis of key
variables such as inlet temperature of each reactor (Tinrx) and
hydrogen to total hydrocarbon ratio (H2/THC) affecting process
performance is performed to identify the operating condition to
maximize the production of propylene. Within the range of operating
conditions applied in the present studies, the operating condition to
maximize the propylene production at the same weighted average
inlet temperature (WAIT) is ΔTinrx1= -2, ΔTinrx2= +1, ΔTinrx3= +1 ,
ΔTinrx4= +2 and ΔH2/THC= -0.02. Under this condition, the surplus
propylene produced is 7.07 tons/day as compared with base case.
Abstract: Intermittent aeration process can be easily applied on
the existing activated sludge system and is highly reliable against the loading changes. It can be operated in a relatively simple way as well.
Since the moving-bed biofilm reactor method processes pollutants by attaching and securing the microorganisms on the media, the process
efficiency can be higher compared to the suspended growth biological
treatment process, and can reduce the return of sludge. In this study,
the existing intermittent aeration process with alternating flow being
applied on the oxidation ditch is applied on the continuous flow stirred tank reactor with advantages from both processes, and we would like
to develop the process to significantly reduce the return of sludge in the clarifier and to secure the reliable quality of treated water by
adding the moving media. Corresponding process has the appropriate
form as an infrastructure based on u- environment in future u- City and
is expected to accelerate the implementation of u-Eco city in conjunction with city based services. The system being conducted in a
laboratory scale has been operated in HRT 8hours except for the final
clarifier and showed the removal efficiency of 97.7 %, 73.1 % and 9.4
% in organic matters, TN and TP, respectively with operating range of
4hour cycle on system SRT 10days. After adding the media, the removal efficiency of phosphorus showed a similar level compared to
that before the addition, but the removal efficiency of nitrogen was
improved by 7~10 %. In addition, the solids which were maintained in
MLSS 1200~1400 at 25 % of media packing were attached all onto the
media, which produced no sludge entering the clarifier. Therefore, the
return of sludge is not needed any longer.
Abstract: Biomass is becoming a large renewable resource for
power generation; it is involved in higher frequency in
environmentally clean processes, and even it is used for biofuels
preparation. On the other hand, hydrogen – other energy source – can
be produced in a variety of methods including gasification of
biomass. In this study, the production of hydrogen by gasification of
biomass waste is examined. This work explores the production of a
gaseous mixture with high power potential from Amazonas´ specie
known as copoazu, using a counter-flow fixed-bed bioreactor.
Abstract: In this study a neural network (NN) was proposed to
predict the sorption of binary mixture of copper-cobalt ions into
clinoptilolite as ion-exchanger. The configuration of the
backpropagation neural network giving the smallest mean square
error was three-layer NN with tangent sigmoid transfer function at
hidden layer with 10 neurons, linear transfer function at output layer
and Levenberg-Marquardt backpropagation training algorithm.
Experiments have been carried out in the batch reactor to obtain
equilibrium data of the individual sorption and the mixture of coppercobalt
ions. The obtained modeling results have shown that the used
of neural network has better adjusted the equilibrium data of the
binary system when compared with the conventional sorption
isotherm models.
Abstract: Stainless steel has been employed in many
engineering applications ranging from pharmaceutical equipment to
piping in the nuclear reactors and storage to chemical products. In
this attempt, simulation of fatigue crack growth based on
experimental results of austenitic stainless steel 304L was presented
using AFGROW code when NASGRO mode laws adopted. Double
through crack at hole specimen is used in this investigation under
constant amplitude loading. Effect of mean stress is highlighted.
Results show that fatigue crack growth rate (FCGR) and fatigue life
were affected by maximum applied load and dimension of hole. An
equivalent of Paris law for this material was estimated.
Abstract: Solution for the complete removal of carbon
monoxide from the exhaust gases still poses a challenge to the
researchers and this problem is still under development. Modeling for
reduction of carbon monoxide is carried out using heterogeneous
reaction using low cost non-noble metal based catalysts for the
purpose of controlling emissions released to the atmosphere. A
simple one-dimensional model was developed for the monolith using
hopcalite catalyst. The converter is assumed to be an adiabatic
monolith operating under warm-up conditions. The effect of inlet gas
temperatures and catalyst loading on carbon monoxide reduction
during cold start period in the converter is analysed.
Abstract: The remediation of water resources pollution in
developing countries requires the application of alternative
sustainable cheaper and efficient end-of-pipe wastewater treatment
technologies. The feasibility of use of South African cheap and
abundant pine tree (Pinus patula) sawdust for development of lowcost
AC of comparable quality to expensive commercial ACs in the
abatement of water pollution was investigated. AC was developed at
optimized two-stage N2-superheated steam activation conditions in a
fixed bed reactor, and characterized for proximate and ultimate
properties, N2-BET surface area, pore size distribution, SEM, pHPZC
and FTIR. The sawdust pyrolysis activation energy was evaluated by
TGA. Results indicated that the chars prepared at 800oC and 2hrs
were suitable for development of better quality AC at 800oC and 47%
burn-off having BET surface area (1086m2/g), micropore volume
(0.26cm3/g), and mesopore volume (0.43cm3/g) comparable to
expensive commercial ACs, and suitable for water contaminants
removal. The developed AC showed basic surface functionality at
pHPZC at 10.3, and a phenol adsorption capacity that was higher than
that of commercial Norit (RO 0.8) AC. Thus, it is feasible to develop
better quality low-cost AC from (Pinus patula) sawdust using twostage
N2-steam activation in fixed-bed reactor.
Abstract: This study is aimed to investigate feasibility of the
aerobic biological process to treat oily wastewater from palm oil food
industry. Effect of aeration and sludge concentrations are studied.
Raw sludge and raw wastewater was mixed and acclimatized for five
days in a stirred tank reactor. The aeration rate (no aeration, low;
1.5L/min and high rate; 2L/min) and sludge concentration (3675,
7350, and 11025mg/L of VSS) were varied. Responses of process
were pH, COD, oil and grease, VSS, and PHB content. It was found
that the treatment can remove 85.1 to 97.1 % of COD and remove
12.9 to 54.8% of oil & grease. The PHB yield was found to be within
0.15% to 2.4% as PHB/VSS ratio and 0.01% to 0.12% as PHB/COD
removed. The higher aeration results a high COD removal and oil &
grease removal, while experiment without aeration gives better PHB
yield. Higher sludge concentrations (11025mg/L VSS) give higher
removal of oil & grease while moderate sludge concentration
(7350mg/L VSS) give better result in COD removal. Higher PHB
yield is obtained in low sludge concentration (3675mg/L).
Abstract: A novel sponge submerged membrane bioreactor
(SSMBR) was developed to effectively remove organics and
nutrients from wastewater. Sponge is introduced within the SSMBR
as a medium for the attached growth of biomass. This paper evaluates
the effects of new and acclimatized sponges for dissolved organic
carbon (DOC) removal from wastewater at different mixed liquor
suspended solids- (MLSS) concentration of the sludge. It was
observed in a series of experimental studies that the acclimatized
sponge performed better than the new sponge whilst the optimum
DOC removal could be achieved at 10g/L of MLSS with the
acclimatized sponge. Moreover, the paper analyses the relationships
between the MLSSsponge/MLSSsludge and the DOC removal efficiency
of SSMBR. The results showed a non-linear relationship between the
biomass parameters of the sponge and the sludge, and the DOC
removal efficiency of SSMBR. A second-order polynomial function
could reasonably represent these relationships.
Abstract: The objective of this study is to evaluate the
occurrence of fungi in aerobic and anoxic activated sludge from
membrane bioreactors (MBRs). Thirty-six samples of both aerobic
and anoxic activated sludge were taken from 2 MBR treating
domestic wastewater. Over a period of eight months 2 samples from
each plant were taken per month. The samples were prepared for
count and definition of fungi. The obtained data show that, sixty
species belonging to 27 genera were collected from activated sludge
samples under aerobic and anoxic conditions. Regarding to the fungi
definition, under aerobic condition the Geotrichum was found at
(8.8%) followed by Penicillium (75.0%), Yeasts (65.7%) and
Trichoderma (55.5%), while Yeasts (77.1%) Geotrichum
candidumand Penicillium (61.1%) species were the most prevalent in
anoxic activated sludge. The results indicate that activated sludge is
habitat for growth and sporulation of different groups of fungi, both
saprophytic and pathogenic.
Abstract: Titanium oxide hollow microspheres were synthesized from organic precursor titanium tetraisopropoxide (TTIP) using continuous spray pyrolysis reactor. Effects of precursor concentration, applied voltage and annealing have been investigated. It was observed that the annealing of the as-synthesized TiO2 hollow microspheres at 2500C, which had an average external diameter of 200 nm, leads to an increase in the size and also more spherical shape. The precursor concentration was found to have a direct impact on the size of the microspheres, which is also evident in the absorption spectrum. The as-prepared TiO2 hollow microspheres exhibited good photocatalytic activity for the degradation of MO.
Abstract: In this study, a reformer model simulation to use
refinery (Farashband refinery, Iran) waste natural gas. In the
petroleum and allied sectors where natural gas is being encountered
(in form of associated gas) without prior preparation for its positive
use, its combustion (which takes place in flares, an equipment through
which they are being disposed) has become a great problem because
of its associated environmental problems in form of gaseous emission.
The proposed model is used to product syngas from waste natural gas.
A detailed steady model described by a set of ordinary differential and
algebraic equations was developed to predict the behavior of the
overall process. The proposed steady reactor model was validated
against process data of a reformer synthesis plant recorded and a good
agreement was achieved. H2/CO ratio has important effect on Fischer-
Tropsch synthesis reactor product and we try to achieve this parameter
with best designing reformer reactor. We study different kind of
reformer reactors and then select auto thermal reforming process of
natural gas in a fixed bed reformer that adjustment H2/CO ratio with
CO2 and H2O injection. Finally a strategy was proposed for prevention
of extra natural gas to atmosphere.
Abstract: The effects of different parameters on the
hydrodynamics of trickle bed reactors were discussed for Newtonian
and non-Newtonian foaming systems. The varying parameters are
varying liquid velocities, gas flow velocities and surface tension. The
range for gas velocity is particularly large, thanks to the use of dense
gas to simulate very high pressure conditions. This data bank has
been used to compare the prediction accuracy of the different
trendlines and transition points from the literature. More than 240
experimental points for the trickle flow (GCF) and foaming pulsing
flow (PF/FPF) regime were obtained for present study.
Hydrodynamic characteristics involving dynamic liquid saturation
significantly influenced by gas and liquid flow rates. For 15 and 30
ppm air-aqueous surfactant solutions, dynamic liquid saturation
decreases with higher liquid and gas flow rates considerably in high
interaction regime. With decrease in surface tension i.e. for 45 and 60
ppm air-aqueous surfactant systems, effect was more pronounced
with decreases dynamic liquid saturation very sharply during regime
transition significantly at both low liquid and gas flow rates.
Abstract: Three alumina-supported Pt-Sn catalysts have been
prepared by means of co-impregnation and characterized by XRD and
N2 adsorption. The influence of catalyst composition and reaction
conditions on the conversion and selectivity were investigated in the
hydrogenation of acetic acid in an isothermal integral fixed bed
reactor. The experiments were performed on the temperature interval
468-548 K, liquid hourly space velocity (LHSV) of 0.3-0.7h-1,
pressures between 1.0 and 5.0Mpa. A good compromise of
0.75%Pt-1.5%Sn can act as an optimized acetic acid hydrogenation
catalyst, and the conversion and selectivity can be tuned through the
variation of reaction conditions.
Abstract: The thermal, epithermal and fast fluxes were
calculated for three irradiation channels at Egypt Second Research
Reactor (ETRR-2) using CITVAP code. The validity of the
calculations was verified by experimental measurements. There are
some deviations between measurements and calculations. This is due
to approximations in the calculation models used, homogenization of
regions, condensation of energy groups and uncertainty in nuclear
data used. Neutron flux data for the three irradiation channels are
now available. This would enable predicting the irradiation
conditions needed for future radioisotope production.
Abstract: Component handling system is one of the important sub systems of Prototype Fast Breeder Reactor (PFBR) used for fuel handling. Core handling system is again a sub system of component handling system. Core handling system consists of in-vessel and ex-vessel subassembly handling. In-vessel core handling involves transfer arm, large rotatable plug and small rotatable plug operations. Modeling and simulation of in-vessel core handling is a part of development of Prototype Fast Breeder Reactor Operator Training Simulator. This paper deals with simulation and modeling of operations of transfer arm, large rotatable plug and small rotatable plug needed for in-vessel core handling. Process modeling was developed in house using platform independent Cµ code with OpenGL (Open Graphics Library). The control logic models and virtual panel were modeled using simulation tool.
Abstract: The production of glass, ceramic materials and many non-ferrous metals (Zn, Cu, Pb, etc.), ferrous metals (pig iron) and others is connected with the use of a considerable number of initial solid raw materials. Before carrying out the basic technological processes (oxidized roasting, melting, agglomeration, baking) it is necessary to mix and homogenize the raw materials that have different chemical and phase content, granulometry and humidity. For this purpose zinc sulfide concentrates differing in origin are studied for their more complete characteristics using chemical, X-ray diffraction analyses, DTA and TGA as well as Mössbauer spectroscopy. The phases established in most concentrates are: β-ZnS, mZnS.nFeS, FeS2, CuFeS2, PbS, SiO2 (α-quartz). With the help of the developed by us a Web-based information system for a continued period of time different mix proportions from zinc concentrates are calculated and used in practice (roasting in fluidized bed reactor), which have to conform to the technological requirements of the zinc hydrometallurgical technological scheme.
Abstract: Removal of PCP by a system combining
biodegradation by biofilm and adsorption was investigated here.
Three studies were conducted employing batch tests, sequencing
batch reactor (SBR) and continuous biofilm activated carbon
column reactor (BACCOR). The combination of biofilm-GAC
batch process removed about 30% more PCP than GAC adsorption
alone. For the SBR processes, both the suspended and attached
biomass could remove more than 90% of the PCP after
acclimatisation. BACCOR was able to remove more than 98% of
PCP-Na at concentrations ranging from 10 to 100 mg/L, at empty
bed contact time (EBCT) ranging from 0.75 to 4 hours. Pure and
mixed cultures from BACCOR were tested for use of PCP as sole
carbon and energy source under aerobic conditions. The isolates
were able to degrade up to 42% of PCP under aerobic conditions in
pure cultures. However, mixed cultures were found able to degrade
more than 99% PCP indicating interdependence of species.
Abstract: A gold coated copper rotating electrode was used to
eliminate surface oxidation effect. This study examined the effect of
electrode rotation on the ozone generation process and showed that an
ozonizer with an electrode rotating system might be a possible way to
increase ozone-synthesis efficiency. Two new phenomena appeared
during experiments with the rotating electrode. First was that ozone
concentration increased to about two times higher than that of the case
with no rotation. Second, input power and discharge area were found
to increase with the rotation speed. Both ozone concentration and
ozone production efficiency improved in the case of rotating electrode
compared to the case with a non-rotating electrode. One possible
reason for this was the increase in discharge length of
micro-discharges during electrode rotation. The rotating electrode
decreased onset voltage, while reactor capacitance increased with
rotation. Use of a rotating-type electrode allowed earlier observation
of the ozone zero phenomena compared with a non-rotating electrode
because, during rotation, the entire electrode surface was functional,
allowing nitrogen on the electrode surface to be evenly consumed.
Nitrogen demand increased with increasing rotation s
Abstract: Water hyacinth has been used in aquatic systems for
wastewater purification in many years worldwide. The role of water
hyacinth (Eichhornia crassipes) species in polishing nitrate and
phosphorus concentration from municipal wastewater treatment plant
effluent by phytoremediation method was evaluated. The objective
of this project is to determine the removal efficiency of water
hyacinth in polishing nitrate and phosphorus, as well as chemical
oxygen demand (COD) and ammonia. Water hyacinth is considered
as the most efficient aquatic plant used in removing vast range of
pollutants such as organic matters, nutrients and heavy metals. Water
hyacinth, also referred as macrophytes, were cultivated in the
treatment house in a reactor tank of approximately 90(L) x 40(W) x
25(H) in dimension and built with three compartments. Three water
hyacinths were placed in each compartments and water sample in
each compartment were collected in every two days. The plant
observation was conducted by weight measurement, plant uptake and
new young shoot development. Water hyacinth effectively removed
approximately 49% of COD, 81% of ammonia, 67% of phosphorus
and 92% of nitrate. It also showed significant growth rate at starting
from day 6 with 0.33 shoot/day and they kept developing up to 0.38
shoot/day at the end of day 24. From the studies conducted, it was
proved that water hyacinth is capable of polishing the effluent of
municipal wastewater which contains undesirable amount of nitrate
and phosphorus concentration.