U.S. patent application number 12/668817 was filed with the patent office on 2010-08-05 for method for producing feedstocks of high quality lube base oil from coking gas oil.
This patent application is currently assigned to SK LUBRICANTS CO., LTD.. Invention is credited to Chang Kuk Kim, Gyung Rok Kim, Sam Ryong Park, Jae Wook Ryu, Jee Sun Shin.
Application Number | 20100193400 12/668817 |
Document ID | / |
Family ID | 39772643 |
Filed Date | 2010-08-05 |
United States Patent
Application |
20100193400 |
Kind Code |
A1 |
Kim; Gyung Rok ; et
al. |
August 5, 2010 |
METHOD FOR PRODUCING FEEDSTOCKS OF HIGH QUALITY LUBE BASE OIL FROM
COKING GAS OIL
Abstract
Disclosed herein is a method of producing feedstock of
high-quality lube based oil by producing coker gas oil (CGO) from
vacuum residue (VR) or a mixture (VR/AR) of atmospheric residue
(AR) and vacuum residue (VR), performing a hydrotreating process
and a hydrocracking process by mixing the coker gas oil (CGO) with
vacuum gas oil (VGO) to form unconverted oil (UCO), and then
recycling the unconverted oil. The method of producing feedstock of
high-quality lube based oil is advantageous in that feedstock of
high-quality lube based oil can be more economically and
efficiently produced using cheap coker gas oil (CGO), which is hard
to treat.
Inventors: |
Kim; Gyung Rok; (Daejeon,
KR) ; Kim; Chang Kuk; (Daejeon, KR) ; Ryu; Jae
Wook; (Daejeon, KR) ; Shin; Jee Sun; (Seoul,
KR) ; Park; Sam Ryong; (Daejeon, KR) |
Correspondence
Address: |
IP GROUP OF DLA PIPER LLP (US)
ONE LIBERTY PLACE, 1650 MARKET ST, SUITE 4900
PHILADELPHIA
PA
19103
US
|
Assignee: |
SK LUBRICANTS CO., LTD.
Seoul
KR
|
Family ID: |
39772643 |
Appl. No.: |
12/668817 |
Filed: |
April 18, 2008 |
PCT Filed: |
April 18, 2008 |
PCT NO: |
PCT/KR08/02205 |
371 Date: |
January 12, 2010 |
Current U.S.
Class: |
208/51 |
Current CPC
Class: |
C10G 69/06 20130101;
C10G 2300/1077 20130101; C10G 2300/107 20130101; C10G 2300/1074
20130101; C10G 2400/10 20130101 |
Class at
Publication: |
208/51 |
International
Class: |
C10B 55/00 20060101
C10B055/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 26, 2007 |
KR |
10-2007-0075100 |
Claims
1-5. (canceled)
6. A method of producing feedstock of high-quality lube base oil
using coker gas oil (CGO), comprising: distilling atmospheric
residue (AR) in a first vacuum distillation unit (V1) and thus
separating the distilled atmospheric residue (AR) into vacuum gas
oil (VGO) and vacuum residue (VR) or a mixture (VR/AR) of
atmospheric residue (AR) and vacuum residue (VR), and then
supplying the vacuum gas oil (VGO) directly to a hydrotreating unit
(HDT) and supplying the vacuum residue (VR) or the mixture (VR/AR)
of atmospheric residue (AR) and vacuum residue (VR) to a first
fractional distillation unit (Fs1); supplying the vacuum residue
(VR) or the mixture (VR/AR) of atmospheric residue (AR) and vacuum
residue (VR), from which fuel components are separated in the first
fractional distillation unit (Fs1), into a coker drum and then
coking it in the coker drum, and then obtaining coker gas oil (CGO)
again through the first fractional distillation unit (Fs1), and
then supplying the obtained coker gas oil (CGO) into the
hydrotreating unit (HDT) together with the vacuum gas oil (VGO);
removing impurities from the coker gas oil (CGO) and vacuum gas oil
(VGO) through the hydrotreating unit (HDT); obtaining light and
heavy hydrocarbons through a hydrocracking unit (HDC); supplying
the light and heavy hydrocarbons into a second fractional
distillation unit (Fs2) to separate them into oil products and
unconverted oil; supplying all of the separated unconverted oil
into a second vacuum distillation unit (V2) to obtain feedstock of
high-quality lube base oil having a predetermined viscosity grade
and balanced unconverted oil; and recycling the unconverted oil
obtained from the second vacuum distillation unit (V2) into the
hydrocracking unit (HDC).
7. The method of producing feedstock of high-quality lube base oil
according to claim 6, wherein a mixing volume ratio (VGO/CGO) of
the vacuum gas oil (VGO) to coker gas oil (CGO), supplied into the
hydrotreating unit (HDT), is 3.about.9.
8. The method of producing feedstock of high-quality lube base oil
according to claim 6, wherein a ratio of the unconverted oil
separated through the second fractional distillation unit (Fs2) to
the unconverted oil recycled into the hydrocracking unit (HDC) is
3:1.about.5:1.
9. The method of producing feedstock of high-quality lube base oil
according to claim 6, wherein a ratio of the unconverted oil
supplied into the second vacuum distillation unit (V2) to the
unconverted oil recycled from the second vacuum distillation unit
(V2) into the hydrocracking unit (HDC) is 1.3:1.about.1.5:1.
10. A method of producing feedstock of high-quality lube base oil
using coker gas oil (CGO), comprising: distilling atmospheric
residue (AR) in a first vacuum distillation unit (V1) and thus
separating the distilled atmospheric residue (AR) into vacuum gas
oil (VGO) and vacuum residue (VR) or a mixture (VR/AR) of
atmospheric residue (AR) and vacuum residue (VR), and then
supplying the vacuum gas oil (VGO) directly to a hydrotreating unit
(HDT) and supplying the vacuum residue (VR) or the mixture (VR/AR)
of atmospheric residue (AR) and vacuum residue (VR) to a first
fractional distillation unit (Fs1); supplying the vacuum residue
(VR) or the mixture (VR/AR) of atmospheric residue (AR) and vacuum
residue (VR), from which fuel components are separated in the first
fractional distillation unit (Fs1), into a coker drum and then
coking it in the coker drum, and then obtaining coker gas oil (CGO)
again through the first fractional distillation unit (Fs1), and
then supplying the obtained coker gas oil (CGO) into the
hydrotreating unit (HDT) together with the vacuum gas oil (VGO);
removing impurities from the coker gas oil (CGO) and vacuum gas oil
(VGO) through the hydrotreating unit (HDT); obtaining light and
heavy hydrocarbons through a hydrocracking unit (HDC); supplying
the light and heavy hydrocarbons into a second fractional
distillation unit (Fs2) to separate them into oil products and
unconverted oil; supplying a part of the separated unconverted oil
into a second vacuum distillation unit (V2) to obtain feedstock of
high-quality lube base oil having a predetermined viscosity grade
and balanced unconverted oil; and recycling the unconverted oil
separated through the second fractional distillation unit (Fs2) and
the unconverted oil obtained from the second vacuum distillation
unit (V2) into the hydrocracking unit (HDC).
11. The method of producing feedstock of high-quality lube base oil
according to claim 10, wherein a mixing volume ratio (VGO/CGO) of
the vacuum gas oil (VGO) to coker gas oil (CGO), supplied into the
hydrotreating unit (HDT), is 3.about.9.
12. The method of producing feedstock of high-quality lube base oil
according to claim 10, wherein a ratio of the unconverted oil
separated through the second fractional distillation unit (Fs2) to
the unconverted oil recycled into the hydrocracking unit (HDC) is
3:1.about.5:1.
13. The method of producing feedstock of high-quality lube base oil
according to claim 10, wherein a ratio of the unconverted oil
supplied into the second vacuum distillation unit (V2) to the
unconverted oil recycled from the second vacuum distillation unit
(V2) into the hydrocracking unit (HDC) is 1.3:1.about.1.5:1.
Description
RELATED APPLICATION
[0001] This is a .sctn.371 of International Application No.
PCT/KR2008/002205, with an international filing date of Apr. 18,
2008 (WO 2009/014303 A1, published Jan. 29, 2009), which is based
on Korean Patent Application No. 10-2007-0075100 filed Jul. 26,
2007.
TECHNICAL FIELD
[0002] The present disclosure relates to a method of producing
feedstock of high-quality lube base oil using coker gas oil (CGO),
and, more particularly, to a method of producing feedstock of
high-quality lube base oil by mixing coker gas oil (CGO) with
vacuum gas oil (VGO) used in a conventional hydrogenation reaction
process, performing a hydrotreating process and a hydrocracking
process, and then recycling the unconverted oil produced
therefrom.
BACKGROUND
[0003] A conventional method of producing feedstock of lube base
oil in relation to a fuel oil hydrocracking process is performed
using unconverted oil (UCO), produced by hydrocracking the vacuum
gas oil (VGO) produced through a vacuum distillation process (V1).
In the conventional method, first, a large amount of oil is
converted into light hydrocarbons through a hydrotreating (HDT)'
process for removing impurities, such as sulfur, nitrogen, oxygen,
metals, and the like, from oil and a hydrocracking (HDC) process,
which is a main reaction process, and various cracked oils and
gases are separated through a series of fractional distillation
processes (Fs) to product light oil. In the reaction, the
conversion rate of oil into light hydrocarbons is about 40%, and it
is impossible in practice to obtain a conversion rate of 100%.
Therefore, in the final fractional distillation process, since
unconverted oil (UCO) always remains, some of the unconverted oil
(UCO) is sent outside and then used as feedstock of lube base oil,
and the remainder thereof is recycled in a hydrocracking
process.
[0004] Since aromatic compounds, sulfur compounds, oxygen
compounds, nitrogen compounds, etc., which are included in the
supplied vacuum gas oil (VGO) in large quantities, are mostly
saturated with hydrogen through a hydrotreating process, 90% or
more of the concomitantly produced unconverted oil (UCO) becomes
saturated hydrocarbons, thus producing oil having a high viscosity
index, the viscosity index being one of the most important
properties of lube base oil.
[0005] Thus, Korean Examined Patent Publication No. 96-13606, filed
by the present applicant and incorporated by reference in its
entirety herein, discloses a method of producing feedstock of
high-quality lube base oil from unconverted oil, in which
unconverted oil (UCO) is directly separated from vacuum gas oil
(VGO) in a recycling mode of a fuel oil hydrocracking process and
is then used as feedstock of lube base oil, so that it is not
required to recycle the unconverted oil (UCO) to a first vacuum
distillation process (an atmospheric residue vacuum distillation
process), with the result that the loads in the first vacuum
distillation process, hydrotreating process and hydrocracking
process are decreased, thereby efficiently producing feedstock of
high-quality lube base oil. Therefore, in the method of producing
feedstock of high-quality lube base oil from unconverted oil,
disclosed in this patent document, feedstock of high-quality lube
base oil having a viscosity of a grade of 100N and 150N can be
efficiently produced, compared to the conventional fuel oil
hydrocracking process of recycling unconverted oil (UCO) to the
first vacuum distillation process and hydrocracking process without
using the unconverted oil (UCO) for producing feedstock of
high-quality lube base oil. However, this method of producing
feedstock of high-quality lube base oil from unconverted oil,
disclosed in this patent document, is designed such that only
vacuum gas oil (VGO) is used, and methods of more economically
producing feedstock of high-quality lube base oil by recycling
unconverted oil (UCO) and using cheap coker gas oil (CGO) have
never been considered.
SUMMARY
[0006] Therefore, the present applicant has repeatedly conducted
research on methods of more efficiently and economically producing
feedstock of high-quality lube base oil. As a result, the present
applicant proposed a method of producing feedstock of high-quality
lube based oil by producing coker gas oil (CGO) from vacuum residue
(VR) or a mixture (VR/AR) of atmospheric residue (AR) and vacuum
residue (VR), mixing the coker gas oil (CGO) with vacuum gas oil
(VGO), performing a hydrotreating process and a hydrocracking
process to form unconverted oil (UCO), and then recycling the
unconverted oil.
[0007] Accordingly, the present disclosure has been made keeping in
mind the above problems occurring in the prior art, and an aspect
of the present disclosure is to provide a method of producing
feedstock of high-quality lube based oil, in which economic
efficiency can be greatly improved by utilizing cheap coker gas
oil, and production efficiency can be maximized by recycling
unconverted oil in a fuel oil hydrocracking process.
[0008] In order to accomplish the above, an aspect of the present
disclosure provides a method of producing feedstock of high-quality
lube base oil using coker gas oil (CGO), including: distilling
atmospheric residue (AR) in a first vacuum distillation unit (V1)
and thus separating the distilled atmospheric residue (AR) into
vacuum gas oil (VGO) and vacuum residue (VR) or a mixture (VR/AR)
of atmospheric residue (AR) and vacuum residue (VR), and then
supplying the vacuum gas oil (VGO) directly to a hydrotreating unit
(HDT) and supplying the vacuum residue (VR) or the mixture (VR/AR)
of atmospheric residue (AR) and vacuum residue (VR) to a first
fractional distillation unit (Fs1); supplying the vacuum residue
(VR) or the mixture (VR/AR) of atmospheric residue (AR) and vacuum
residue (VR), from which fuel components are separated in the first
fractional distillation unit (Fs1), into a coker drum and then
coking it in the coker drum, and then obtaining coker gas oil (CGO)
again through the first fractional distillation unit (Fs1), and
then supplying the obtained coker gas oil (CGO) into the
hydrotreating unit (HDT) together with the vacuum gas oil (VGO);
removing impurities from the coker gas oil (CGO) and vacuum gas oil
(VGO) through the hydrotreating unit (HDT); obtaining light and
heavy hydrocarbons through a hydrocracking unit (HDC); supplying
the light and heavy hydrocarbons into a second fractional
distillation unit (Fs2) to separate them into oil products and
unconverted oil; supplying all of the separated unconverted oil
into a second vacuum distillation unit (V2) to obtain feedstock of
high-quality lube base oil having a predetermined viscosity grade
and balanced unconverted oil; and recycling the unconverted oil
obtained from the second vacuum distillation unit (V2) into the
hydrocracking unit (HDC).
[0009] Another aspect of the present disclosure provides a method
of producing feedstock of high-quality lube base oil using coker
gas oil (CGO), including: distilling atmospheric residue (AR) in a
first vacuum distillation unit (V1) and thus separating the
distilled atmospheric residue (AR) into vacuum gas oil (VGO) and
vacuum residue (VR) or a mixture (VR/AR) of atmospheric residue
(AR) and vacuum residue (VR), and then supplying the vacuum gas oil
(VGO) directly to a hydrotreating unit (HDT) and supplying the
vacuum residue (VR) or the mixture (VR/AR) of atmospheric residue
(AR) and vacuum residue (VR) to a first fractional distillation
unit (Fs1); supplying the vacuum residue (VR) or the mixture
(VR/AR) of atmospheric residue (AR) and vacuum residue (VR), from
which fuel components are separated in the first fractional
distillation unit (Fs1), into a coker drum and then coking it in
the coker drum, and then obtaining coker gas oil (CGO) again
through the first fractional distillation unit (Fs1), and then
supplying the obtained coker gas oil (CGO) into the hydrotreating
unit (HDT) together with the vacuum gas oil (VGO); removing
impurities from the coker gas oil (CGO) and vacuum gas oil (VGO)
through the hydrotreating unit (HDT); obtaining light and heavy
hydrocarbons through a hydrocracking unit (HDC); supplying the
light and heavy hydrocarbons into a second fractional distillation
unit (Fs2) to separate them into oil products and unconverted oil;
supplying some of the separated unconverted oil into a second
vacuum distillation unit (V2) to obtain feedstock of high-quality
lube base oil having a predetermined viscosity grade and balanced
unconverted oil; and recycling the unconverted oil separated
through the second fractional distillation unit (Fs2) and the
unconverted oil obtained from the second vacuum distillation unit
(V2) into the hydrocracking unit (HDC).
[0010] According to the method of producing feedstock of
high-quality lube based oil of the present disclosure, the
feedstock of high-quality lube based oil can be produced by
producing coker gas oil (CGO) from vacuum residue (VR) or a mixture
(VR/AR) of atmospheric residue (AR) and vacuum residue (VR), mixing
the coker gas oil (CGO) with vacuum gas oil (VGO), performing a
hydrotreating process and a hydrocracking process to form
unconverted oil (UCO), and then recycling the unconverted oil.
Therefore, the method of producing feedstock of high-quality lube
based oil according to the present disclosure is advantageous in
that feedstock of high-quality lube based oil can be more
economically and efficiently produced using cheap coker gas oil
(CGO), which is hard to treat.
[0011] Those skilled in the art will appreciate that various
modifications, additions and substitutions are possible, without
departing from the scope and spirit of the disclosure as disclosed
in the accompanying claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a schematic process view showing a fuel oil
hydrocracking process and a process of producing feedstock of lube
base oil in a recycling mode according to an exemplary embodiment
of the present disclosure.
[0013] Hereinafter, an exemplary embodiment of the present
disclosure will be described in detail with reference to the
attached drawings.
DETAILED DESCRIPTION
[0014] The following are descriptions of elements shown in the
drawings:
[0015] CGO: coker gas oil VGO: vacuum gas oil
[0016] UCO: unconverted oil CDU: crude distillation unit
[0017] AR: atmospheric residue VR: vacuum residue
[0018] V1: first vacuum distillation unit
[0019] V2: second vacuum distillation unit
[0020] HDT: hydrotreating unit
[0021] HDC: hydrocracking unit
[0022] Fs1: first fractional distillation unit Fs2: second
fractional distillation unit
[0023] As described above, FIG. 1 is a schematic process view
showing a hydrocracking process using coker gas oil (CGO) supplied
from a coker drum and vacuum gas oil (VGO) supplied from a first
vacuum distillation unit (V1), and a method of producing feedstock
of lube base oil in a recycling mode according to an exemplary
embodiment of the present disclosure. In the method of producing
feedstock of lube base oil, shown in FIG. 1, vacuum residue (VR) or
a mixture (VR/AR) of atmospheric residue (AR) and vacuum residue
(VR), other than vacuum gas oil (VGO), is supplied to the first
fractional distillation unit (Fs1) and a coker drum and is coked in
the coker drum, and is then formed into coke gas oil (CGO) through
the first fractional distillation unit (Fs1) again, and then the
coker gas oil (CGO) is mixed with the vacuum gas oil (VGO), and
then the mixture of the coker gas oil (CGO) and the vacuum gas oil
(VGO) is supplied into a hydrotreating unit and is then formed into
light oil and unconverted oil (UCO) through a hydrocracking unit
(HDC), thereby producing feedstock of high-quality lube base oil
using the unconverted oil (UCO).
[0024] More specifically, in the method of producing feedstock of
lube base oil, shown in FIG. 1, atmospheric residue (AR) separated
through a crude distillation unit is distilled in a first vacuum
distillation unit (V1) and is thus separated into vacuum gas oil
(VGO) and vacuum residue (VR) or a mixture (VR/AR) of atmospheric
residue (AR) and vacuum residue (VR). Then, the vacuum gas oil
(VGO) is directly supplied to a hydrotreating unit (HDT), and the
vacuum residue (VR) or the mixture (VR/AR) of atmospheric residue
(AR) and vacuum residue (VR) is supplied to a first fractional
distillation unit (Fs1). Subsequently, the vacuum residue (VR) or
the mixture (VR/AR) of atmospheric residue (AR) and vacuum residue
(VR), from which fuel components have been separated in the first
fractional distillation unit (Fs1), is supplied to a coker drum and
is coked in the coker drum, and is then formed into coke gas oil
(CGO) through the first fractional distillation unit (Fs1) again.
Subsequently, the formed coke gas oil (CGO) is supplied to a
hydrotreating unit (HDT) together with the vacuum gas oil
(VGO).
[0025] The process of producing the coker gas oil (CGO) will be
described in more detail. Components having a low boiling point are
separated from the vacuum residue (VR) or the mixture (VR/AR) of
atmospheric residue (AR) and vacuum residue (VR), which is
separated through the first vacuum distillation unit (V1), through
the first fractional distillation unit (Fs1), and residual oil is
introduced into a coker drum and is then rapidly heated to the
temperature at which coke can be sufficiently formed. For this,
steam is supplied into the coker drum together with the residual
oil in order to maintain the minimum speed and residence time in a
heater coil and prevent the formation of coke. The liquid remaining
in the coker drum is converted into coke and light hydrocarbon gas,
and the light hydrocarbon gas is discharged through the upper end
of the coker drum. In order to perform this process, at least two
coker drums are required. While coke is formed in one coker drum,
in the another coker drum, the flow of oil is stopped, and coke is
removed from the other coker drum. Since the coker gas oil (CGO)
produced through such a coking process has poor oxidation stability
and includes a large amount of HPNA (High Poly-Nuclear Aromatic
hydrocarbon) having 7 or more aromatic rings, the unconverted oil,
which is produced by supplying this coker gas oil (CGO) to the
hydrotreating unit and hydrocracking unit, is not suitable for use
as feedstock of high-quality lube base oil. However, as the method
of the present disclosure, when the unconverted oil (UCO) is
recycled into the hydrocracking unit (HDC), the production of
high-quality unconverted oil (UCO), having good oxidation stability
and including a small amount of HPNA, can be secured, feedstock of
high-quality lube base oil, having a grade of 100 D to 150 D can be
maximized, and the coker gas oil (CGO), having been used as
conventional bunker C oil or raw material for producing diesel oil
(DSL), can be used as feedstock of high-quality lube base oil, thus
improving economic efficiency due to high added value.
[0026] The specific conditions in the coking process according to
the exemplary method of the present disclosure are given in Table
1.
TABLE-US-00001 TABLE 1 Operation condition (unit) Range Heater
discharge temperature (.degree. C.) 480~500 Coker drum temperature
(.degree. C.) 500~600 Pressure of upper end of coker drum (psig)
15~30 Recycle ratio (recycle volume/supply volume) 0.05~0.2
[0027] The coker gas oil (CGO) produced through a coking process is
mixed with vacuum gas oil (VGO), and the mixture thereof is
supplied into a hydrotreating unit (HDT). In this case, in the
mixing of the coker gas oil (CGO) and vacuum gas oil (VGO), when
the amount of the vacuum gas oil (VGO) is increased, the production
amount of high-quality lube base oil is increased, but the
production cost thereof is also increased. In contrast, when the
amount of the coker gas oil (CGO) is increased, there is an
advantage in that the production cost of the high-quality lube base
oil is decreased, but there is a problem in that the material
properties of the coker gas oil (CGO) are not as good as those of
the vacuum gas oil (VGO), and thus it is preferred that the mixing
volume ratio of the vacuum gas oil (VGO) and coker gas oil (CGO) be
3.about.9. The typical material properties of the vacuum gas oil
(VGO) and coker gas oil (CGO) supplied into the hydrotreating unit
(HDT), and those of the unconverted oil (UCO) obtained through a
hydrogenation reaction, are given in Table 2.
TABLE-US-00002 TABLE 2 Material properties of Products in feedstock
in hydrogenation reaction hydrogenation VGO CGO feedstock reaction
UCO API/Sp. Gr. 20.9/0.9285 17.8/0.9478 20.9/0.9285 39.76/0.9409
Sulfur/ 2620/16500 3120/2653 2700/1823 LT1.0/LT1.0 nitrogen, wtppm
C7 insoluble 350 806 500 0.02 material, wt % Fe, wtppm .sup. 1.1
LT1.0 .sup. 1.1 LT1.0 Ni, wtppm LT1.0 LT1.0 LT1.0 LT1.0 V, wtppm
LT1.0 LT1.0 LT1.0 LT1.0 Distillation, ASTM D1160, @760 mmHg,
.degree. C. Initial 274 246 274 265.1 boiling point 5% 363 354 363
379.7 10% 393 380 391 397.6 30% 429 416 426 414.5 50% 456 434 451
436.6 70% 484 453 478 464.9 90% 538 486 529 500.8 95% 569 499 554
519.8 End point 590 -- 590 --
[0028] The hydrotreating unit (HDT) is a unit for removing
impurities, such as sulfur, nitrogen, oxygen, metals, etc., from
feedstock. The raw material passes through the hydrotreating unit
(HDT), and is then converted into light hydrocarbons through a
hydrocracking reaction in the hydrocracking unit (HDC) in large
quantities. The hydrotreating unit (HDT) and hydrocracking unit
(HDC) can be operated in a once-through mode or in a recycling
mode, and can be configured in various modes, such as a one-stage
mode, a two-stage mode, and the like.
[0029] The light and heavy hydrocarbons produced through the
hydrocracking unit (HDC) are supplied to a second fractional
distillation unit (Fs2), and are thus separated into oil products
and unconverted oil (UCO). All or some of the separated unconverted
oil (UCO) is supplied to a second vacuum distillation unit (V2),
and thus feedstock of high-quality lube base oil having a
predetermined viscosity grade is separated therefrom, and residual
unconverted oil (UCO) is obtained.
[0030] Further, the residual unconverted oil (UCO), obtained from
the second vacuum distillation unit (V2), is recycled into the
hydrocracking unit (HDC). Meanwhile, when only some of the
separated unconverted oil (UCO) is selectively supplied to the
second vacuum distillation unit (V2), the residual unconverted oil
(UCO) obtained from the second fractional distillation unit (Fs2)
and the residual unconverted oil (UCO) obtained from the second
vacuum distillation unit (V2) are simultaneously recycled into the
hydrocracking unit (HDC).
[0031] In this example, it is preferred that the ratio of the
unconverted oil separated through the second fractional
distillation unit (Fs2) to the unconverted oil recycled into the
hydrocracking unit (HDC) be 3:1.about.5:1. Further, it is preferred
that the ratio of the unconverted oil supplied into the second
vacuum distillation unit (V2) to the unconverted oil recycled from
the second vacuum distillation unit (V2) into the hydrocracking
unit (HDC) be 1.3:1.about.1.5:1.
[0032] The second vacuum distillation unit (V2) is operated at a
tower bottom temperature of 320.about.350.degree. C. and a tower
bottom pressure of 140.about.160 mmHg and at a tower top
temperature of 75.about.95.degree. C. and a tower top pressure of
60.about.80 mmHg, and the feedstock of lube base oil, having a
predetermined viscosity grade, obtained from the second vacuum
distillation unit (V2), may further be dewaxed and stabilized.
[0033] Therefore, according to the present disclosure, when
atmospheric residue (AR) is supplied into the first vacuum
distillation unit (V1), vacuum residue (VR) is separated through
the first vacuum distillation unit (V1), coker gas oil (CGO) is
extracted from the vacuum residue (VR) such that the volume of the
coker gas oil is about 10.about.25% of the volume of the vacuum
residue (VR), the extracted coker gas oil (CGO) is mixed with the
vacuum residue (VR), and the mixture thereof can be used as
feedstock in the hydrotreating unit (HDT) and hydrocracking unit
(HDC). Therefore, the present disclosure is advantageous in that
about 10.about.30% of the atmospheric residue (AR) can further be
converted into high value-added light oil and feedstock of
high-quality lube base oil, compared to the case where only vacuum
gas oil is used as a feedstock.
[0034] Hereinafter, the present disclosure will be described in
more detail with reference to the following examples for
illustration purposes only, but the scope of the present disclosure
is not limited thereto.
Example 1
[0035] Components having a low boiling point were separated from
vacuum residue (VR), which was separated from atmospheric residue
(AR) through a first vacuum distillation unit (V1), through a first
fractional distillation unit (Fs1), and then the vacuum residue
(VR) was heated to a temperature of 500.degree. C. and then
introduced into a coker drum. Subsequently, the vacuum residue (VR)
was heated to a temperature of 550.degree. C. at a coker drum upper
end pressure of 25 Psig in the coker drum, and thus the liquid
remaining in the coker drum was converted into coke and light
hydrocarbon gas, and the light hydrocarbon gas was separated into
LPG, Gas, naphtha, and coker gas oil (CGO) through the first
fractional distillation unit (Fs1). The coker gas oil (CGO) and
vacuum gas oil (VGO) having the material properties given in Table
2 were treated in a hydrotreating unit (HDT) using a catalyst
(UF-210STARS, manufactured by UOP Corp.) under conditions of an
LHSV (Liquid Hourly Space Velocity) of 3.429 hr.sup.-1, a pressure
of 2397 Psig, a temperature of 385.8.degree. C. and a hydrogen
influx rate of 842 Nm.sup.3/m.sup.3, and were then further treated
together with the recycled unconverted oil (UCO), described later,
in a hydrocracking unit (HDC) using a catalyst
(UF-210/HC-115/UF-100, manufactured by UOP Corp.) under conditions
of an LHSV of 1.241 a pressure of 2397 Psig, a temperature of
395.2.degree. C. and a hydrogen influx rate of 1180
Nm.sup.3/m.sup.3.
[0036] Subsequently, diesel oil and light oil products having a
boiling point of 350.degree. C. or lower were recovered through a
general fractional distillation process, and the unconverted oil
(UCO), having the material properties given in Table 2 above, was
obtained. The obtained unconverted oil (UCO) was vacuum-distilled
in a UCO vacuum distillation unit (V2) at a tower top pressure of
75 mmHg and a tower top temperature of 80.degree. C. and at a tower
bottom pressure of 150 mmHg and a tower bottom temperature of
325.degree. C., thus obtaining a light distillate in an amount of
36.3 LV %, a 100N distillate in an amount of 33.4 LV %, a middle
distillate in an amount of 10.5 LV %, and a 150N distillate, which
is a tower bottom product, in an amount of 19.8 LV %, as given in
Table 3 below.
[0037] Among these distillates, only 100N distillate and 150N
distillate were extracted from the unconverted oil (UCO) supplied
into the second vacuum distillation unit (V2) such that the amount
of 100N distillate and 150N distillate is 53.2% (that is, 100N:
33.4% and 150N: 19.8%) of the amount of the supplied unconverted
oil (UCO), and residual unconverted oil (UCO) (46.8% of the amount
of the supplied unconverted oil) was recycled into a VGO
hydrocracking unit (HDC). Through these processes, 100N and
150N-grade feedstock of high-quality lube base oil having a high
viscosity index and low volatility was produced, as shown in Table
3 below, and it was found that 53.2% of the unconverted oil (UCO)
was recycled, so that a function for preventing fire-resistant
components and poly-nuclear aromatic compounds from being
accumulated was automatically accomplished, and the respective
first vacuum distillation unit (V1) and hydrotreating unit (HDT)
have extra capacities, with the result additional treatment
capacities corresponding to the produced amount of the feedstock of
lube base oil were provided, thereby very efficiently utilizing
facilities.
TABLE-US-00003 TABLE 3 Light 100N Middle 150N distillate distillate
distillate distillate API 37.6 37.3 36.7 36.0 Distillation, ASTM
D1160, @760 mmHg, .degree. C. Initial boiling 337 398 412 438 point
5% 356 408 428 446 10% 360 411 434 452 30% 374 418 443 459 50% 381
425 459 473 70% 389 429 478 493 90% 400 445 503 529 95% 404 455 532
551 End point 411 469 533 560 Viscosity, cSt @40.degree. C. 19.28
@100.degree. C. 2.968 4.28 5.065 6.751 Viscosity index 113 133 --
-- Flash point 210 246 (COC), .degree. C. Pour point, .degree. C.
33 39
Comparative Example
[0038] The vacuum gas oil (VGO), which was separated from
atmospheric residue (AR) through a first vacuum distillation unit
(V1), having the material properties given in Table 2 above, was
hydrotreated in a hydrotreating unit (HDT) using a catalyst (UF-210
STARS, manufactured by UOP Corp.) under conditions of an LHSV
(Liquid Hourly Space Velocity) of 3.429 hr.sup.-1, a pressure of
2397 Psig, a temperature of 385.8.degree. C. and a hydrogen influx
rate of 842 Nm.sup.3/m.sup.3, and was then further treated together
with the recycled unconverted oil (UCO) described later in a
hydrocracking unit (HDC) using a catalyst (UF-210/HC-115/UF-100,
manufactured by UOP Corp.) under the conditions of an LHSV of 1.241
hr.sup.-1, a pressure of 2397 Psig, a temperature of 395.2.degree.
C. and a hydrogen influx rate of 1180 Nm.sup.3/m.sup.3.
[0039] Subsequently, diesel oil and light oil products having a
boiling point of 350.degree. C. or lower were recovered through a
general separating process and several fractional distillation
processes, and the unconverted oil (UCO) having the material
properties given in the following Table 4 was obtained. The
obtained unconverted oil (UCO) was vacuum-distilled in an UCO
vacuum distillation unit (V2) at a tower top pressure of 75 mmHg
and a tower top temperature of 80.degree. C. and at a tower bottom
pressure of 150 mmHg and a tower bottom temperature of 325.degree.
C., thus obtaining a light distillate in an amount of 32.5 LV %, a
100N distillate in an amount of 34.8 LV %, a middle distillate in
an amount of 14.6 LV %, and a 150N distillate, which is a tower
bottom product, in an amount of 18.1 LV %, as given in Table 4
below.
[0040] Among these distillates, only the 100N distillate and the
150N distillate were extracted from the unconverted oil (UCO)
supplied into the second vacuum distillation unit (V2) such that
the amount of 100N distillate and 150N distillate was 52.9% (that
is, 100N: 34.8% and 150N: 18.1%) of the amount of the supplied
unconverted oil (UCO), and residual unconverted oil (UCO) (47.1% of
the amount of the supplied unconverted oil) was recycled into a
hydrocracking unit (HDC). Through these processes, 100N and
150N-grade feedstock of high-quality lube base oil having a high
viscosity index and low volatility was produced, as shown in Table
4 below.
TABLE-US-00004 TABLE 4 Light 100N Middle 150N UCO distillate
distillate distillate distillate API 39.5 37.4 37.1 36.5 35.9
Distillation, ASTM D1160, @760 mmHg, .degree. C. Initial 276 338
401 412 437 boiling point 5% 368 358 410 428 449 10% 398 362 412
434 453 30% 432 376 418 443 461 50% 457 383 424 459 475 70% 485 392
432 478 496 90% 537 403 447 503 531 95% 567 406 456 532 552 End
point 590 414 471 533 562 Viscosity, cSt @40.degree. C. 20 19.39
@100.degree. C. 4.428 2.978 4.305 5.065 6.787 Viscosity 136 113 132
-- -- index Flash point 212 250 (COC), .degree. C. Pour 33 39
point, .degree. C.
[0041] Comparing Example 1 of the present disclosure with
Comparative Example of a conventional technology, the hydrocracking
conditions in both Example 1 and Comparative Example are similar to
each other. However, unlike the Comparative Example, in which only
vacuum gas oil (VGO) is used as a feedstock, in Example 1 of the
present disclosure, 10.about.25% of the coker gas oil (CGO)
produced from vacuum residue (VR) or a mixture (VR/AR) of vacuum
residue (VR) and atmospheric residue (AR) is mixed with the vacuum
gas oil (VGO) and the mixture of the coker gas oil (CGO) and vacuum
gas oil (VGO) can be used as a feedstock, and the unconverted oil
(UCO) formed in this manner is recycled into a hydrocracking unit
(HDC), so that feedstock of lube base oil having material
properties similar to those of a conventional feedstock of lube
base oil can be produced, with the result that about 10.about.30%
of vacuum gas oil (VGO) can be replaced with the coker gas oil
(CGO), compared to Comparative Example, showing a conventional
technology. That is, when the production of the feedstock of lube
base oil is evaluated based on the same amount of atmospheric
residue (AR), in Example 1 of the present disclosure, a large
amount of high value-added light oil and feedstock of high-quality
lube base oil can be produced, compared to Comparative Example,
showing a conventional technology.
[0042] The foregoing examples are provided merely for the purpose
of explanation and are in no way to be construed as limiting. While
reference to various embodiments are shown, the words used herein
are words of description and illustration, rather than words of
limitation. Further, although reference to particular means,
materials, and embodiments are shown, there is no limitation to the
particulars disclosed herein. Rather, the embodiments extend to all
functionally equivalent structures, methods, and uses, such as are
within the scope of the appended claims.
* * * * *