The tank is the only acceptable way for storing, collecting and transporting oil and it is products. But because of improper maintenance tank may come to a state disrepair. In order to avoid this process, there are regular cleaning of the container carried out using different methods. This article discusses and analyzes methods for cleaning commercial oil tanks in order to identify the most cost-effective, most effective and safe technology. Keywords: tank, oil, bottom sediments, cleaning. Скачать в формате PDF
26 American Scientific Journal № (34) / 20 20
Saidov Jafar Jamshedovich
Student of Kazan National
Research Technological University, Uzbekistan, Bukhara.
E -mail: jafar97s00mail.ru

Abstrack. The tank is the only acce ptable way for storing, collecting and transporting oil and it is products.
But because of improper maintena nce tank may come to a state disrepair. In order to avoid this process, there are
regular cleaning of the container carried out using different meth ods. This article discusses and analyzes methods
for cleaning commercial oil tanks in order to identify the most cost-effective, most effective and safe technology.
Keywords : tank, oil, bottom sediments, cleaning.

When storing the paraffini c oil in the tanks,
particularly tanks of large volume, bottom sediments
are formed and accumulated. Stock b ottoms
precipitation leads to underutilization of the capacity of
oil storage tanks, as well as the occurrence of corrosio n-
hazardous water under le ns precipitate, to difficulty in
the examination state of the tank, etc. In addition, the
accumulation of se diments leads to complication of
process operation reservoirs to increase the material
costs in transportation and storage system, and
eventually to reduce the technical and economic
indicators of oil tanks and transport system as a whole. Relevance:

To im prove the efficiency of use of tank
containers the useful volume of oil tanks must be
preserved. In the global oil industr y, the issue of
cleaning bottom sediments and precipitations is
relevant. Cleaning tanks from deposits is a dangerous
and time -consumi ng job requiring significant financial
costs. This is an unavoidable phenomenon resulting
from the deposition of crude oil from suspended and
agglom erated components. As bottom sediments
thicken and are difficult to erode over time, the tank is
periodicall y cleaned.

The frequency of tank cleaning is set by the state
technical inspection. It depends on the characteristics
of the stored fuel, its typ e, and in which way it is used
for. In practice, various combinations of methods for
controlling bottom and pyrophoric deposits are used to achieve the greatest technical and economic effect. The
study and development of new met hods to solve this
problem i s a promising and relevant direction. Diagram
1 shows percentage of minimum and maximum
composition of botto m sediments.

Tank cleaning technology :
• Oil pumping
• Preparing bottom sludge for pumping
•Preliminary degassing
• Tank cleaning
• Degassing of gas
• Control of quality
• Disposal of bottom sludges
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American Scientifi c Journal № ( 34) / 2 0 20 27

Diagram 1. Composition of bottom sediments

Compare the approximate cost of the work and
choose the most optimal method for cleaning tanks with
volumes from 1000m
Oil sludge in tanks is a sand -clay base,
impregnated with oil produc ts and water. The content
of mechanical impurities in the sludge can reach to 50 -90%, and carbohydrate products
- 10- 40%. Oil sludge is
graphica lly shown in the diagram 2. The fractional
composition of oil deposits is a mixture of asphaltenes
(6 -25%), paraf fins (1-4%), oils (70 -80%) and
associated water (0.3 -8%). The fractional composition
is graphically shown in the diagr am 3.

Diagram 2. Oil sl udge

Diagram 3. The fractional composition

Tank cleaning is laborious and responsible process
that requires increased attention to the safety and
effectiveness of it is implementation. A large number of methods have been d
eveloped for cleaning tanks
f rom bottom sediments, the choice of a method depends
on the design of the tank, the nature of the deposits, etc.
WaterSolid particles
Minimum composition
Maximum composition
Oil sludge
Mechanical impurities
carbohydrate products
The fractional composition
Bound water
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28 American Scientific Journal № (34) / 20 20
The most commonly used methods are manual
cleaning, mechanical cleaning, and chemical
mechanized cleaning. Manual cleaning is carried out by en tering a
person into the tank, removing deposits using a hand
tool and removing sludge to eliminate. After that, the
tank is washed with water at a pressure of 29 -44 psi and
a temperature of 86 -122 ˚F and the pre -installed pump
pumps out the wash water wit h sludge. This method
leads to long downtime of the tank and requires serious
organizational and technical measur es aimed at
ensuring safety and reducing harm to the health of
workers. Also, the disadvantages of this method
inc lude the fact that it is diff icult to extract
hydrocarbons suitable for use from the precipitate with
this method. In this regard, despite the cheapness, in
recent years, this method is practically not used in
world practice.
The mechanized method of clean ing tanks with
special mechan ical washing machines and robots can
significantly reduce cleaning time, downtime of tanks
and significantly redu ce the consequences of damage to
the health of workers. However, the mechanized
method of cleaning tanks has a sig nificant drawback,
namely the occurrence of a "cutting" effect
1 of the
washing jets, which reduces the cleaning efficiency and
leads to the de struction of the tank. For example,
mechanical tank cleaning offered by Atlantic Waste
Solutions (AWS)
2 consists i n circulating bottom sludge
and re -weighing sludge using powerful ATEX certified
pumps and sophisticated sweeps immersed in the liquid
phase o f the tank. Mixing components, such as pure
crude oil, diesel fuel or water, are added to facilitate
ci rculation a nd slurry suspension. This mixing process
makes it easy to pump the contents of the oil tank into
a separate storage area, such as the next ta nk.
Significantly empty tank is now ready for cleaning. The
tank prepared for cleaning with the help of robots and
remotely controlled high -pressure treatment plants is
cleaned of residual oil and deposits. Once precipitate
and sediment has been removed, p ersonnel can enter
the tank for final cleaning. Internal surfaces, including
the lower part of the tank roof, inte rnal roofs, walls and
floor, are cleaned with a jet of washing composition
with a high -pressure detergent. The final cleaning of the
tank allo ws the air to be cleaned of gas inside so that
the tank can be inspected, maintained and repaired.
Based on the re sults of tank cleaning, AWS will arrange
for the tank and wall plate to be inspected by an
independent licensed inspector in accordance with A PI 653, using approved methods such as magnetic
scanning and ultrasound scanning.
The chemically -mechan ized method of cleaning
consists of the use of solutions of specially selected
detergents sprayed by washing machines at a solution
temperature of 113 –122 ˚F. This method improves the
quality of cleaning, the intensity of the cleaning process
and the minim um use of manual labor. The main
advantage of this method, in addition to using low -
temperature solutions, is the ability to isolate a liquid
hydrocarbon with a content of 5% water. The main
disadvantages of this cleaning method include the need
to wash ou t the residual deposits by diluting them with
oil, because when mixed with detergent solutions, they
are activated and can change the composition of the gas
medium in the tank and lead to the formation of high
concentrations of explosive vapors in the air. Chemical -
m echanized cleaning of tanks from various deposits is
currently one of the leading positions in the world
practice and is used by many companie s. But even the
most progressive stripping method, the chemically -
mechanized one, does not exclude manu al labor and
people staying in the gassed zone inside the tank. One
of the leaders in commodity tank cleaning is FQE
3, which has developed its own cleaning
method that allows recovery of up to 98% of oil and
secondary materials. The cleaning comp lex includes
water cannons (Manway cannons) installed in side
manholes, tank cleaning machines, high pressure
pumps (high head pump, high head prime -assi st pump),
chemical tanks (frac tanks for cutter and chemical
storage), a separator for the output of li quefied products
for further processing and sale (liquefied products to
storage, reprocessing, sale). In the first purification
step, FQE Chemicals perso nnel mix the hydrocarbon
diluent with the chemical additives selected according
to the composition of t he deposits (FQE ™ Solvent -H)
and establish fluid circulation cycles. Sludge deposits,
which would otherwise remain solids for disposal, are
liquefied an d pumped out of the tank for further
processing. Liquid circulation is provided by standard
pumping equ ipment, as well as through cleaning
nozzles on the roof, which can be routed to anywhere
in the tank. At the second stage, the tank is degassed
using mod ern chemical compounds for degassing /
decontamination. These compounds are non -hazardous
water -based substances t hat clean the air space and the
inner surface of the tank of hydrocarbon vapors and
residual oil films. Table 1 shows a comparison of the
appr oximate cost of tank cleaning.
Table 1.
Comparison of estimated tank cleaning costs.
Index Atlantic Was te Solutio n FQE Chemicals
Tank volume, gallon From 1000 From 1000
The percentage recovery of hydrocarbons, % - 95 -98
Cleaning Cost, $ US / 1000 gallon $279 $500
1 Gimaletdinov G.M., Sattarova D.M. Methods for
cleaning a nd preventing the accumulation of sediment
in tanks. Oil and gas business.
2 Atlantic Waste Solutions. [ Electronic resource].
Access mode: URL:
http://www.atlanticwa stesolutions.com/?p=56/
3 Tank Cleaning Process - FQE Chemicals. [Electronic
resource ]. Access mode: URL:
https://fqechemicals.com/processes/tank -cleaning/
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American Scientifi c Journal № ( 34) / 2 0 20 29

Based on this, the most effective cleaning method
is chemical -mechanized, consisting in the use of a
paraffin solvent in combination with stirring and
heating of the sediments. Such technology reduces the
time and labor costs and a llows the hydrocarbon part to
be extracted from the sediments. Looking at the
approximate cost table, we can con clude that the
Atlantic Waste Solutions system is more economically
advantageous than chemical cleaning from FQE
Chemicals. But if you consider that the Atlantic Waste
Solutions installation requires manual tank cleaning,
which is approximately $ 1600, the n chemical cleaning
is more beneficial not only from an economic point of
view, but also from the point of view of ensuring
industrial safety. List of references:

1. Gimaletdinov G.M., Sattarova D.M. Methods
for cleaning and preventing the accumulation of
sediment in tanks. Oil and gas business.
2. Kam E.K.T., 2001. Assessment of sludges and
tank bottoms treatment processes, The 8
th International
Petroleum Environmental Conference. November 6 –9.
Houston. Integrated Petrole um Environmental
3. Tan k Cleaning Process - FQE Chemicals.
[Electronic resource]. Access mode: URL:
https://fqechemicals.com/processes/tank -cleaning/
4. Atlantic Waste Solutions. [Electronic resource].
Access mode: URL:
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