This a laboratory report of an experiment conducted at the American University of Nigeria as a requirement of completing the Petroleum Science course.

1. Eric Hagenimana February 24, 2015
A00015905
CHE 310
Group 1 members: Immaculata, Kadidjah
Crude Oil Dewaxing
Abstract
The aim of this experiment was to separate wax from crude oil samples by using a solvent
extraction method. Acetone was used as solvent in this experiment. Two samples of crude oil
from different regions were used, Urals and Escravos crude oil samples. Generally, density of
non-dewaxed crude oil was found to be greater than the density of the dewaxed crude oil sample.
For example, the density of Ural before dewaxing is 0.835 while the density of Ural after
dewaxing is 0.689. Dewaxed crude samples are much lighter than non-dewaxed crude samples.
Dewaxed crude sample have lower pour; in this experiment non-dewaxed sample of urals was
found to have a higher pour point compared to escravos this due to the fact urals has much wax
than escravos.
Introduction
Dewaxing is a process of removing wax compounds from the desired product of crude oil by
introducing a solvent into a petroleum stream. Dewaxing with selective solvents at low
temperatures is very important and unavoidable in the production of lube oils from paraffin base
crude oils. Petroleum dewaxing is used to extract high molecular weight components, often
referred to as waxes, from a petroleum stream. Wax in crude oil cause petroleum products to
solidify at higher temperatures. They also can affect the combustion performance of diesel and
gasoline fuels. Dewaxing is very important because long-chain n-paraffins ranging from 16–60
carbon atoms in particular (petroleum wax) are responsible for very high pour point of oil and for
near-ambient temperature precipitation.
Materials and chemicals
Urals and Escravos crude oil samples, beakers, acetone, ice water, thermometers, and solvent
extractor were used as materials.
Procedures
First of all, 50 ml of each crude oil sample was measured using a measuring cylinder and poured
into a beaker, and then to each of the samples in the beaker, 50 ml of acetone was added. The
mixture was allowed to form a precipitate. Afterwards, the beakers were immersed in a mixture
of water/ice to see if there will be further precipitation. The residues were filtered off and the

2. filtrate collected. The de-waxed oil and the acetone were Separated using a Rotor-vapor at
vacuum pressure of 556 mmHg (760 mmHg = 1 atmosphere) and at 40oC. The densities were
measured for both the untreated sample and the de-waxed sample. Comparison between the
appearances and the densities of the untreated sample and the de-waxed sample was done and
tabulated. Finally, the determination of pour points of both dewaxed and untreated samples was
performed.
Results and Discussion
Table of Results and Result Discussions
Crude
Samples/properties
URALS before
dewaxing
URALS after
dewaxing
Escravos
before
dewaxing
Escravos
after
dewaxing
Appearance Dark Brown,
heavy texture
Dark brown, light
texture
Brown, heavy
texture
Brown, Light
texture
Density (g/mL) 0.835 0.689 0.784 0.645
Pour Point 3.7o
C - 2o
C -
As shown in the table above, urals has a higher pour point compared to escravos, and this is
because urals contains much wax content. From density, also it is clear that urals is heavier than
escravos. The dewaxed samples of both escravos and urals are lighter than their parent samples
because the wax was removed. During the pour point determination, both dewaxed samples took
longer (many hours) than expected to solidify; that is why their values are not shown in the table.
However, based on non-dewaxed samples it can be predicted that dewaxed escravos has a lower
pour point compared to dewaxed urals.
Conclusion
Dewaxing is a process of removing wax compounds from the desired product of crude oil by
introducing a solvent into a petroleum stream. Dewaxing with selective solvents at low
temperatures is very important and unavoidable in the production of lube oils from paraffin base
crude oils. Generally, density of non-dewaxed crude oil was found to be greater than the density
of the dewaxed crude oil sample. Dewaxed crude samples are much lighter than non-dewaxed
crude samples. Dewaxed crude sample have lower pour compared to non-dewaxed.
Reference
Petroleum Science Lab Manual
Samir, Matar and Lewis .F, Hatch. Chemistry of Petrochemical Process, 2nd Ed.