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1. LUBE OIL
MANUFACTURING
PROCESS
R A J AT T I WA R I
C S J M A 1 4 0 0 1 3 9 0 2 1 4
C H E - 2 K 1 4
C H - 1 0 ( 1 0 . 4 - 1 0 . 7 )

2. Hydrofinishing
Process
Solvent Deasphalting
Process
Solvent Extraction
of Lube Oil
Fractions
Solvent
Dewaxing
Process
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 Introduction
 Process Description
 Flowsheet
 Process Variables
 Operating Condition
& Yield Pattern

4.  Solvent deasphalting process is employed to remove asphalt from vacuum
residues to produce very heavy lubricating oils, called the bright stocks.
 The most commonly used solvent for deasphalting is propane.
 Other light hydrocarbons are used are used either alone or combined with
propane, depending on the nature of feedstock and quality of deasphalted oil to
optimize process yield and operating cost.
 Propane extracts the high quality oils in the vacuum residues by precipitating
the asphaltenic and resinous components containing metals, sulphur and
nitrogen.
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5.  Feed is heated to the specified temperature and then charged to the top of the
extractor.
 Liquid propane is pumped from the propane accumulator and introduced in the
bottom portion of the extractor.
 Propane moves upward and contacts with the descending feed.
 The oil fractions are extracted from the vacuum residue.
 The extract (deasphalted oil + propane) is taken from the top and the raffinate
(asphalt solution) is taken from the bottom of the extractor.
 Propane is recovered from both the deasphalted oil solution(85% propane) and
the asphalt solution(30 – 50% propane).
PROCESS DESCRIPTION
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7.  Extraction temperature
For maximum extraction of valuable hydrocarbons from the
feed, the temperature in the extractor is maintained at 50 – 65°C
at the bottom and 75 – 85°C at the top.
 Extraction Pressure
The pressure in the extractor is maintained at 3.5 – 4 MPa.
 Solvent to feed ratio
This is determined by the nature of the feedstock and the
temperature of deasphalting.
PROCESS VARIABLE
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Extractor Pressure ( Mpa) 3.5 – 4
Temperature (°C)
(a) Top
(b) Bottom
75 – 85
50 – 65
Solvent to feed ratio (vol./vol.) 5 - 13
Product Yield wt%
Deasphalted oil 33
Asphalt + Loss 67

9.  Introduction
Comparison of Solvents
 Process Description
 Flowsheet
 Operating Conditions &
Yield Pattern
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10.  Solvent extraction is the most widely used method of removing aromatics and
other undesirable constituents from lube oil fractions.
 The following characteristics are to be considered in the selection of a solvent
for use in commercial solvent extraction process.
a) Solvent should possess high selectivity for undesirable components.
b) Solvent must be stable to avoid its chemical or thermal degradation.
c) Solvent must be adaptable to a wide range of feedstocks.
d) Solvent must be available at reasonable cost.
e) Solvent must be non – corrosive to conventional material of
construction.
f) Solvent must be non – toxic, i.e. environmentally safe.
 The most common solvents used for solvent extraction process are furfural,
phenol and N–methyl-2-pyrrolidone (NMP).
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Solvents Furfural NMP Phenol
Selectivity Excellent Very Good Good
Adaptibility Excellent Very Good Good
Extraction Temperature Moderate Low Intermediate
Corrosivity Intermediate Low Moderate
Energy Cost Moderate Low Intermediate
Investment cost Intermediate Low Moderate
Maintenance Cost Low Low Moderate
Operating Cost Intermediate Low Moderate

12.  The charge oil is fed to the bottom section of the extraction column (Rotating
Disc Contactor – RDC).
 Solvent furfural is fed to the upper section of the RDC. The intermediate extract
from the bottom of the RDC is cooled and routed to the outside settler.
 The bottom layer is the final extract phase, which is transferred to the extract
recovery section.
 The upper layer is recycled to the bottom section of the RDC. The raffinate phase
leaves the the RDC at the top and is collected in a surge vessel.
 Furfural is removed from the raffinate phase by flashing and steam stripping.
 Flashing takes place in the furfural column that operates at atmospheric pressure.
The vapour of this column is condensed and collected in the dry furfural
accumulator.
PROCESS DESCRIPTION
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13.  The bottoms from the pressure flash column still contain a few percentage of
furfural, which is then removed by flashing and steam stripping under vacumm.
 The overhead product of the strippers is collected in the phase separator, where it
separates into two layers:
 a lower layer of furfural saturated with water
 an upper layer of water saturated with furfural
 The wet furfural layer is fed to the top of the furfural column, where it is
fractioned into two components:
 an azeotrope as overhead product, which is returned after condensation to the
phase separator
 dry furfural as the bottom product
 The water layer is fed from the phase separator to the water removal column,
where it is fractioned into two components :
 an azeotrope as overhead, which is returned to the phase separator
 bottom product consisting of furfural-free water, which is discarded.
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Process Variable Feedstock
Spindle HVI Intermediate
Neutral HVI
Intermediate
Neutral LVI
Heavy
Neutral HVI
Bright
Neutral HVI
Extractor
temperature (°C)
(a) Top 105 122 85 130 135
(b) Bottom 55 72 60 80 90
Solvent to feed
ratio, (wt./wt.)
2.5 3.1 1.1 3.9 3.7
Product Yield wt.%
Raffinate 58
Extract + Loss 42

16.  Introduction
 Process Description
 Flowsheet
 Operating Conditions
& Yield Pattern
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17.  Solvent dewaxing is one of the most important processing steps in the manufacture of
lube oil base stocks.
 It is a process of removing waxy components.
 Except for a relatively small production from special wax-free naphthenic crudes, all
stocks must be dewaxed or they would not flow at ambient temperature.
 Types of dewaxing processes:
 Propane Dewaxing
 Ketone Dewaxing
 Ketone dewaxing accounts for about 80% of the worldwide capacity.
 It is one of the most expensive process because it includes solvent handling,
refrigeration facilties as well as costly mechanical equipments like rotary vacuum filters
and scraped-surface double pipe heat exchanges.
 The ketone dewaxing process commonly uses a mixture of methyl ethyl ketone (MEK)
with either toluene or methyl isobutyl ketone (MIBK).
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18.  Waxy oil feed is mixed with the solvent and heated to a temperature 20-30°C.
 The charge mixture is then cooled to the temperature of about -20°C.
 The crystallization takes place partly in scraped surface heat exchangers, where
heat is removed by exchange with cold filtrate and the remainder in scraped-
surface chillers where heat is removed by a refrigerant, such as propane or
ammonia.
 The chilled mixture flows to the filters by gravity. Filteration takes place in
continuous rotary vaccum filters.
 In the filters the crystallized wax is separated from the oil in the form of a thin
cake, washed with chilled solvent and removed from the drum by blowing back
with inert gas.
 The filter cake is transferred by screw conveyers to the wax boots, from which
the cake slurry is pumped via steam heaters to the slack wax solvent recovery
system.
PROCESS DESCRIPTION
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19.  The solvent is recoverd from both the dewaxed oil and the slack wax by
evaporation.
 The solvent free dewaxed oil is pumped to storage.
 For the removal of water from the solvent a ketone fractionator is installed.
 The streams containing water, viz., the stripper overheads, are led to the
decanting vessel, where two layers are formed :
 a lower layer of water saturated with solvent
 an upper layer of solvent saturated with water
 The water layer is fed to the ketone fractionator.
 Here the solvent is evaporated and leaves overhead with some water as an
azeotropic mixture, after condensation it is recycle to the decanter.
 The water from the bottom of the ketone fractionator is solvent free and is
dicarded.
PROCESS DESCRIPTION
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Dewaxing Temperature (°C) -10 to -20
Solvent to oil ratio (vol./vol.) 0.75 – 1.5
a) Spindle HVI 3.8
b) IN (HVI) 5.4
C) HN (HVI) 5.3
d) BN (HVI) 6.4
Product Yield wt%
Dewaxed oil 74
Slack wax + Loss 26

23.  Introduction
 Process Description
Flowsheet
 Operating Conditions
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24.  Hydrofinishing process stabilizes the undesirable oil components
by catalytic hydrogenation.
 The undesirable components such as sulphur, oxygen, nitrogen
react with hydrogen to form H2S, water and ammonia respectively.
 These components, if not removed, may cause corrosion.
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25.  The feedstock is mixed with hydrogen rich gas and recycle gas.
 This mixture is preheated and then passed over a fixed bed of catalyst in the
reactor.
 The catalyst used in this process are oxides of Co-Mo, Ni-Mo, Ni-Co-Mo,
supported on alumina.
 The reaction products after heat exchange with reactor charge and further cooling
are flashed in a high- pressure separator.
 The hydrogen rich gas is recycled to the feed inlet.
 The liquid product is passed to a low-pressure separator in order to remove the
bulk of dissolved H2S before passing to the stripping and drying column.
 The yield of the product is of the order of 98-99 wt%.
PROCESS DESCRIPTION
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Reactor Pressure (kgf/cm2) 30 – 50
Reactor Temperature (°C) 280 – 340
Space Velocity ( h-1) 0.75 – 1.5
Recycyle H2 (Litres of pure H2 at NTP/ litre of feed
at 15°C)
150

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