Iraqi Journal of Chemical and Petroleum Engineering

In the literature, several correlations have been proposed for bubble size prediction in bubble columns. However these
correlations fail to predict bubble diameter over a wide range of conditions. Based on a data bank of around 230
measurements collected from the open literature, a correlation for bubble sizes in the homogenous region in bubble
columns was derived using Artificial Neural Network (ANN) modeling. The bubble diameter was found to be a function
of six parameters: gas velocity, column diameter, diameter of orifice, liquid density, liquid viscosity and liquid surface
tension. Statistical analysis showed that the proposed correlation has an Average Absolute Relative Error (AARE) of
7.3 % and correlation coefficient of 92.2%. A comparison with selected correlations in the literature showed that the
developed ANN correlation noticeably improved the prediction of bubble sizes. The developed correlation also shows
better prediction over a wide range of operation parameters in bubble columns.

In this paper a nonlinear adaptive control method is presented for a pH process, which is difficult to control due to the
nonlinear and uncertainties. A theoretical and experimental investigation was conducted of the dynamic behavior of
neutralization process in a continuous stirred tank reactor (CSTR). The process control was implemented using different
control strategies, velocity form of PI control and nonlinear adaptive control. Through simulation studies it has been
shown that the estimated parameters are in good agreement with the actual values and that the proposed adaptive
controller has excellent tracking and regulation performance.

The isomerization of n-hexane on platinum loaded acidic zeolite was studied at atmospheric pressure, H2/nC6 molar
ratios of 1-4 and temperature range of 240-270ºC.
The measured kinetic data were fitted to an equation based on the bifunctional mechanism and by using independently
obtained dehydrogenation and adsorption data. The activation energies of protonation (∆Hpro) and the elementary
isomerization step (Eact,iso) and as well as the corresponding preexponential factor were simultaneously determined.
The observed values of both ∆Hpro and Eact,iso are in agreement with the results of quantum-chemical calculations.

Selective recovery of atropine from Datura innoxia seeds was studied. Applying pertraction in a rotating film contactor
(RFC) the alkaloid was successfully recovered from native aqueous extracts obtained from the plant seeds. Decane as a
liquid membrane and sulfuric acid as a stripping agent were used. Pertraction from native liquid extracts provided also
a good atropine refinement, since the most of co-extracted from the plant species remained in the feed or membrane
solution. Solid–liquid extraction of atropine from Datura innoxia seeds was coupled with RF-pertraction in order to
purify simultaneously the extract obtained from the plant. Applying the integrated process, proposed in this study, a
product containing 92.6% atropine was obtained.

This study was concerned with using ozone gas in drinking water treatment plant at Ibn-Sina Company. The main
purpose of this research is to find the best contactor for ozone unit proposed. An investigation was conducted to study
the absorption of ozone by water in two type of absorber. The effects of the process variables (such as height of water
column, contact time, and pH) on the amount of ozone absorbed were investigated. Box-Wilson central composite
rotatable design is used to design the experimental work for the mentioned variables. It was found that the optimum
value of the variables studied was:
i) Height of water column (90 cm)
ii) Contact time (17-18 min)
iii) PH (7 - 7.5)

The present investigation is concerned for the purification of impure zinc oxide (80-85 wt %) by using petroleum coke
(carbon content is 76 wt %) as reducing agent for the impure zinc oxide to provide pure zinc vapor, which will be
oxidized later by air to the pure zinc oxide.
The operating conditions of the reaction were studied in detail which are, reaction time within the range (10 to 30 min),
reaction temperature (900 to 1100 oC), air flow rate (0.2 to 1 l/min) and weight percentage of the reducing agent
(petroleum coke) in the feed (14 to 30 wt %).
The best operating conditions were (30 min) for the reaction time, (1100 oC) for the reaction temperature, (1 l/min) for
the air flow rate, and (30 wt %) of reducing material (petroleum coke) in the feed.
Under the above conditions, conversion of zinc oxide was (68.12 %) and the purity of the produced zinc oxide was
(97.85 %) by using petroleum coke as reducing material.

This work was carried to study the capability of activated alumina from bauxite compared with activated carbon
adsorption capability to reduce the color content from Al-Hilla Textile Company wastewater. Six dyes were studied from
two types(reactive and dispersed) namely (blue, red, yellow) from wastewater and aqueous solutions.
Forty eight experiments were carried out to study the effect of various initial conditions (bed height, flow rate, initial
concentration, pH value, temperature, and competitive adsorption) on adsorption process.
The results showed that the adsorption process using activated carbon insured a good degree of color reduction
reaching (99.7%) and was better than activated bauxite which reached (95%

Vacuum gas oil (611-833)K was distilled from Kirkuk crude oil, which was obtained by blending the following fraction,
light vacuum gas oil (611 - 650) K, medium vacuum gas oil (650-690)K, heavy vacuum gas oil (690-727)K and very
heavy vacuum gas oil (727-833)K.
The vacuum gas oil was hydrotreated on a commercial cobalt-molybdenum alumina catalyst presulfied at specified
condition in a laboratory trickle bed reactor. The reaction temperature varied from (583-643)K over liquid hourly space
velocity ranging between (1.5-3.75)h-1 , Hydrogen pressure was kept constant at 3.5 MPa with a hydrogen to oil ratio
of about 250 L/L
The conversion results for desulfurization appeared to obey the second order kinetics. According to this model rate
constants for desulfurization reaction were calculated. Finally, the apparent activation energy (Ea), enthalpy of
activation (

H*) and entropy (

S*) were calculated based on the values of rate constant (k). The calculated values of
Ea,

H* and

S* were 74.657 kJ/mole, 74.712 kJ/mole and 167.132 J/mole.k, respectively.