Iraqi Journal of Chemical and Petroleum Engineering

This work deals with thermal cracking of slack wax produced as a byproduct from
solvent dewaxing process of medium lubricating oil fraction in AL-Dura refinery. The
thermal cracking process was carried out at a temperature ranges 480-540 ºC and
atmospheric pressure. The liquid hourly space velocity (LHSV) for thermal cracking
was varied between 1.0-2.5

. It was found that the conversion increased (61 - 83)
with the increasing of reaction temperature (480 - 540) and decreased (83 - 63) with
the increasing of liquid hourly space velocity (1.0 - 2.5).
The maximum gasoline yield obtained by thermal cracking process (48.52 wt. % of
feed) was obtained at 500 ºC and liquid hour space velocity 1

. The obtaining
liquid product at the best operating condition 500 ºC and LHSV 1
was
fractionated into wide range fractions. Based on the determination of some properties
for the distilled fractions and comparison (these properties with that required by
standard requirements) it is possible to use the fractions of cracking products as a
component for production of automobile gasoline, domestic kerosene, light diesel fuel
and basic lubricating oils

The inhibitor property of curcuma longa L. extract in different concentrations of
simulated refinery wastewater (0.05% - 2% wt) and at various temperatures (30, 35
and 40 ˚C) was investigated using weight loss method. The results showed that the
presence of about 1.2 % (v/v) of curcuma extract gave about 84% inhibition
indicating its effectiveness on mild steel corrosion in simulated refinery wastewater,
besides the adsorption process on the mild steal surface obeyed the Langmuir
adsorption isotherm.

Sixteen polycyclic aromatic hydrocarbons (PAHs) concentrations were measured in
aerosol samples collected for the period from April 2012 to February 2013 at thermal
south power station of Baghdad. Fourty one aerosol sample were extracted with (1:1)
dichloromethane and methanol using soxhlet for seventeen hour. The extraction
solution was analyzed applying GC/MS. The PAH concentrations outside thermal
south power station were higher than those inside it, and higher in summer season
than in winter. Naphthalene, pyrene, Anthracene, Indeno [1, 2, 3-cd] pyrene and
Phenanthrene were the most abundant PAHs detected in all points at the site
sampling. The total polycyclic aromatic hydrocarbon (TPAH) and total suspended
particles (TSP) concentrations were measured during the measurement period. For
individual PAH compounds, the results showed a strong correlation with each other
(0.998 - 0.77) at both sites

In the present work, the efficiency of Tri-octyl Methyl Ammonium Chloride
(TOMAC) ionic liquid was investigated as new and green demulsifier for three types
of Iraqi crude oil emulsions (Nafut Khana (NK), Kirkuk and Basrah). The separation
efficiency was studied at room temperature and by using microwave heating
technique. Several batch experiments were done to specify the suitable conditions for
the emulsification and demulsification which were specified as 45 minutes and 3000
rpm for crude oil emulsification while the ionic liquid doses were (500,300,150,50)
ppm and the conditions of microwave heating were 1000 watt and 50 second as
irradiation time. The results were very encouraging especially for NK and Kirkuk
crude oil emulsions where the separation efficiency was between (100%-95%) in both
cases (by microwave heating and at room temperature demulsification). The
separation percentages of Basrah crude emulsion varied but as a general result, the
efficiency was acceptable for high doses at the same time, while for low doses, the
water removal ratio was not good as the previous one.

The present work describes the adsorption of Ba2+ and Mg2+ions from aqueous
solutions by activated alumina in single and binary system using batch adsorption.
The effect of different parameters such as amount of alumina, concentration of metal
ions, pH of solution, contact time and agitation speed on the adsorption process was
studied. The optimum adsorbent dosage was found to be 0.5 g and 1.5 g for removal
of Ba2+ and Mg2+
, respectively. The optimum pH, contact time and agitation speed,
were found to be pH 6, 2h and 300 rpm, respectively, for removal of both metal ions.
The equilibrium data were analyzed by Langmuir and Freundlich isotherm models
and the data fitted well to both isotherm modes as indicated by higher correlation of
determination R2
> 0.87 in both single and binary systems. Pore diffusion model for
batch adsorption was used to predict the concentration decay curve for adsorption of
Ba2+ and Mg2+ onto activated alumina. There was a good agreement between the
experimental data and the predicted decay curves using pore diffusion model.

Many carbonate reservoirs in the world show a tilted in originally oil-water contact
(OOWC) which requires a special consideration in the selection of the capillary
pressure curves and an understanding of reservoir fluids distribution while initializing
the reservoir simulation models.
An analytical model for predicting the capillary pressure across the interface that
separates two immiscible fluids was derived from reservoir pressure transient
analysis. The model reflected the entire interaction between the reservoir-aquifer
fluids and rock properties measured under downhole reservoir conditions.
This model retained the natural coupling of oil reservoirs with the aquifer zone and
treated them as an explicit-region composite system; thus the exact solutions of
diffusivity equation could be used explicitly for each region. The reservoir-aquifer
zones were linked by a capillary transition zone that reflected the pressure difference
across the free water level.
The principle of superposition theorem was applied to perform this link across the
free water level to estimate the reflected aquifer pressure drop behavior that holds the
fluid contacts in their equilibrium positions.
The results of originally oil water contact positions generated by the proposed
model were compared with data obtained from a carbonate oil field; the results given
by the model showed full agreement with the actual field data.

The main aim of this study is to evaluate the remaining oil in previously produced
zones, locate the water productive zone and look for any bypassed oil behind casing
in not previously perforated intervals. Initial water saturation was calculated from
digitized open hole logs using a cut-off value of 10% for irreducible water saturation.
The integrated analysis of the thermal capture cross section, Sigma and
Carbon/oxygen ratio was conducted and summarized under well shut-in and flowing
conditions. The logging pass zone run through sandstone Zubair formation at north
Rumaila oil field. The zones where both the Sigma and the C/O analysis show high
remaining oil saturation similar to the open hole oil saturation, could be good oil
zones that do not appear to be water flooded. The zones where the Sigma analysis
shows high residual oil saturation, which is close to open hole oil saturation and the
C/O analysis, show medium residual oil saturation; this could indicate that these
zones were fresh water flooded to a certain extent and they still keep some residual
oil. If the C/O analysis shows low residual oil saturation, it indicates that these zones
were probably fresh water flooded thoroughly. If both Sigma analysis and the C/O
analysis show medium residual oil saturation, most probably these zones were saline
water flooded to a certain extent and they still keep some residual oil.

Viscosity is one of the most important governing parameters of the fluid flow, either
in the porous media or in pipelines. So it is important to use an accurate method to
calculate the oil viscosity at various operating conditions. In the literature, several
empirical correlations have been proposed for predicting crude oil viscosity.
However, these correlations are limited to predict the oil viscosity at specified
conditions. In the present work, an extensive experimental data of oil viscosities
collected from different samples of Iraqi oil reservoirs was applied to develop a new
correlation to calculate the oil viscosity at various operating conditions either for
dead, saturated or under saturated reservoir. Validity and accuracy of the new
correlation was confirmed by comparing the obtained results of this correlation and
other ones, with experimental data for Iraqi oil samples. It was observed that the new
correlation gave the most accurate agreement with the experimental data.