U.S. patent application number 14/734276 was filed with the patent office on 2015-12-10 for recycling method of sludge recovery oil.
The applicant listed for this patent is SK Incheon Petrochem Co., Ltd., SK Innovation Co. Ltd.. Invention is credited to Ki Seok Choi, Chang Woo Joo, Kwan Bum Lee, Min Seob Lee, Sung Ho Lee, Yong Jae Lee, Soojung Park.
Application Number | 20150353846 14/734276 |
Document ID | / |
Family ID | 54769076 |
Filed Date | 2015-12-10 |
United States Patent
Application |
20150353846 |
Kind Code |
A1 |
Joo; Chang Woo ; et
al. |
December 10, 2015 |
Recycling Method of Sludge Recovery Oil
Abstract
Provided is a recycling method of recovery oil including: a)
recovering sludge accumulated in a crude oil tank; b) separating
the sludge into recovery oil, water, and sediment; and c) mixing
the recovery oil with crude oil and performing fractional
distillation on a mixture of the recovery oil and the crude
oil.
Inventors: |
Joo; Chang Woo; (Daejeon,
KR) ; Park; Soojung; (Daejeon, KR) ; Lee; Kwan
Bum; (Daejeon, KR) ; Lee; Min Seob; (Daejeon,
KR) ; Choi; Ki Seok; (Daejeon, KR) ; Lee; Sung
Ho; (Daejeon, KR) ; Lee; Yong Jae; (Daejeon,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SK Innovation Co. Ltd.
SK Incheon Petrochem Co., Ltd. |
Seoul
Seoul |
|
KR
KR |
|
|
Family ID: |
54769076 |
Appl. No.: |
14/734276 |
Filed: |
June 9, 2015 |
Current U.S.
Class: |
208/187 |
Current CPC
Class: |
C10G 53/02 20130101;
C10G 29/20 20130101 |
International
Class: |
C10G 53/02 20060101
C10G053/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 9, 2014 |
KR |
10-2014-0069092 |
Claims
1. A recycling method of recovery oil comprising the steps of: a)
recovering sludge accumulated in a crude oil tank; b) separating
the sludge into recovery oil, water, and sediment; and c) mixing
the recovery oil with crude oil and performing fractional
distillation on a mixture of the recovery oil and the crude
oil.
2. The recycling method of recovery oil of claim 1, wherein in step
c), the recovery oil and the crude oil are mixed with each other by
any one or two or more selected among c1) a method of mixing the
recovery oil with the crude oil using a line mixer and transferring
the mixture to a charge pump; c2) a method of periodically mixing
the recovery oil with the crude oil and transferring the mixture to
the charge pump; and c3) a method of mixing the recovery oil with
the crude oil passing through the charge pump and transferring the
mixture to a desalter.
3. The recycling method of recovery oil of claim 2, wherein c1)
includes: c1-1) mixing the recovery oil with the crude oil using
the line mixer; and c1-2) transferring the crude oil mixed with the
recovery oil to the charge pump.
4. The recycling method of recovery oil of claim 3, wherein the
crude oil passing through step c1-2) is again sent to step c1-1)
and is circulated.
5. The recycling method of recovery oil of claim 2, wherein in step
c2), a process of stopping the supply of the recovery oil for 0.2
to 1 hour after the recovery oil is supplied and mixed with the
crude oil for 0.5 to 3 hours is repeated.
6. The recycling method of recovery oil of claim 2, wherein the
crude oil of c3) is preheated to a temperature of a pour point or
more of the recovery oil.
7. The recycling method of recovery oil of claim 6, wherein the
crude oil is preheated to a temperature of 90 to 150.degree. C.
8. The recycling method of recovery oil of claim 2, wherein 0.1 to
2 parts by weight of the recovery oil are mixed with 100 parts by
weight of the crude oil.
9. The recycling method of recovery oil of claim 1, wherein step a)
is performed by any one or two or more selected among a mechanical
separating method, a thermal separating method, a solvent
extracting method, a sound wave separating method, and a chemical
separating method.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to Korean Patent
Application No. 10-2014-0069092 filed Jun. 09, 2014, the disclosure
of which is incorporated herein by reference in its entirety.
TECHNICAL FIELD
[0002] The following disclosure relates to a recycling method of
recovery oil. More particularly, the following disclosure relates
to a recycling method of recovery oil capable of recycling the
recovery oil and expecting a profitability improving effect by
recovering the recovery oil from sludge accumulated in a crude oil
tank and then mixing the recovery oil with crude oil.
BACKGROUND
[0003] Generally, crude oil, which means petroleum in a natural
state coming out of an oil well without being subjected to a
processing process or a refining process, indicates a sticky liquid
having several hydrocarbon compounds as a main component and having
a blackish brown color. The crude oil includes impurities such as
sulfur, oxygen, a nitrogen compound, a metal, moisture, gas, and
the like, as well as the hydrocarbon compounds, which are the main
component. These impurities are mixed with rust generated from a
pipe or a tank wall at the time of transferring the crude oil, a
naturally generated solid material, an insoluble material, and the
like, such that they become sludge and are accumulated on a lower
portion of a storage tank.
[0004] A crude oil storage tank of an oil refinery should
compulsorily undergo a periodic test at a period of generally 8 to
10 years due to a risk of oil spill by a leak, even though the
period is different for each nation. In this case, crude oil sludge
accumulated in the crude oil storage tank is cleaned and
discharged. In addition, in the case in which an oil spill accident
is generated in spite of this previous periodical test, the sludgy
should be cleaned in order to repair the crude oil storage tank.
Since the sludge is generally generated and accumulated at a rapid
speed, it is accumulated in the crude oil storage tank and
decreases a utilization space in the crude oil storage tank. In
addition, when the sludge is not removed for a long period of time,
such that it is accumulated at height of a crude oil outlet, the
sludge overflows the tank to be introduced into the subsequent
process, thereby having a negative influence on an entire process.
Particularly, when a level of the sludge becomes higher than the
height of the crude oil outlet, a large amount of sludge is
introduced into a process in an instant, which causes a problem
such as a crude oil charge pump trip, and the like. In addition,
when the sludge is introduced into the process, many negative
influences such as a decrease in a lifespan of a heat exchanger in
the process, a decrease in a lifespan of a catalyst, throughput
loss due frequent filter driving of a catalyst process, and the
like are caused.
[0005] It is important to process and discard the sludge as well as
remove the sludge from the tank. As a method of processing the
sludge, there are an incineration method, a physical refining
method using a refinery, or the like, chemical refining method of
processing the sludge using iso oxane and gas oil, and the like.
However, recovery oil separated by the above-mentioned refining
methods has a limitation in being used due to a high pour point and
a high content of impurities. In addition, there are several
limitations in operating a processing process such as securing a
margin tank, or the like.
RELATED ART DOCUMENT
Patent Document
[0006] U.S. Pat. No. 04,014,780 (Mar. 29, 1977)
[0007] U.S. Pat. No. 05,085,710 (Feb. 4, 1992)
SUMMARY
[0008] An embodiment of the present invention is directed to
providing a recycling method of recovery oil capable of overcoming
disadvantages of the recovery oil such as a high pour point, a low
flash point, and a high content of impurities and expecting a
profitability improving effect by recovering the recovery oil from
sludge accumulated in a crude oil tank and then mixing the recovery
oil with crude oil.
[0009] In one general aspect, a recycling method of recovery oil
includes: a) a step of recovering sludge accumulated in a crude oil
tank; b) a step of separating the sludge into recovery oil, water,
and sediment; and c) a step of mixing the recovery oil with crude
oil and performing fractional distillation on a mixture of the
recovery oil and the crude oil.
[0010] In the step c), the recovery oil and the crude oil may be
mixed with each other by any one or two or more selected among c1)
a method of mixing the recovery oil with the crude oil using a line
mixer and transferring the mixture to a charge pump; c2) a method
of periodically mixing the recovery oil with the crude oil and
transferring the mixture to the charge pump; and c3) a method of
mixing the recovery oil with the crude oil passing through the
charge pump and transferring the mixture to a desalter.
[0011] Exemplary embodiments described above are not limited to
contents described above, but include all contents that may be
easily changed by those skilled in the art. As an example, there
may be a case of using another type of apparatus in order to
execute the same technology.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIGS. 1 to 3 illustrate a process of mixing recovery oil and
crude oil with each other according to an exemplary embodiment of
the present invention.
DETAILED DESCRIPTION OF EMBODIMENTS
[0013] Hereinafter, a recycling method of recovery oil according to
an exemplary embodiment of the present invention will be described
in detail with reference to the accompanying drawings. The
accompanying drawings to be provided below are provided by way of
example so that the idea of the present invention can be
sufficiently transferred to those skilled in the art to which the
present invention pertains. Therefore, the present invention is not
limited to the accompanying drawings provided below, but may be
modified in many different forms. In addition, the accompanying
drawings suggested below will be exaggerated in order to clear the
spirit and scope of the present invention. In addition, like
reference numerals denote like elements throughout the
specification.
[0014] Technical terms and scientific terms used in the present
specification have the general meaning understood by those skilled
in the art to which the present invention pertains unless otherwise
defined, and a description for the known function and configuration
unnecessarily obscuring the gist of the present invention will be
omitted in the following description and the accompanying
drawings.
[0015] First, a recycling method of recovery oil according to an
exemplary embodiment of the present invention may include a) a step
of recovering sludge accumulated in a crude oil tank; b) a step of
separating the sludge into recovery oil, water, and sediment; and
c) a step of mixing the recovery oil with crude oil and performing
fractional distillation on a mixture of the recovery oil and the
crude oil.
[0016] The crude oil used in the present invention generally means
a combustible liquid existing in a natural state in the ground and
having a brown to black color. In addition, the crude oil may
include several types of hydrocarbons and impurities, and
components of the crude oil may be changed depending on a drilling
region and a kind of hydrocarbon. However, the present invention is
not limited thereto.
[0017] Properties of the sludge accumulated in the crude oil tank
may be changed depending on stored crude oil, a cleaning period,
and the like. In addition, a method of recovering the accumulated
sludge may also be changed. For example, in the case of light oil,
a small amount of sludge is generated, and the sludge may be
cleaned using water. In the case of medium oil, the sludge and
oiliness on a wall surface may be dissolved and removed using light
oil. Further, in the case of bunker oil, since the sludge is in a
solid-phase at room temperature, the sludge solidified on the
bottom of the crude oil tank may be dissolved and removed.
[0018] The sludge according to the present invention may contain 5
to 28 wt % of water, but is not limited thereto. In the case of
pure sludge, that is, sediment, a content of asphaltene or
inorganics may be 2 to 38 wt %. Particularly, these inorganics
include iron (Fe) as a main component, and an iron component in
these inorganics may be increased due to corrosion of the crude oil
tank as a tank storage time becomes long. In addition to these
components, a wax component, sand, other coke precursors, and the
like, may be further included in the sludge.
[0019] The asphaltene, which is a component insoluble in n-hexane
and soluble in toluene, may be sunk as a solid particle in the
crude oil to form the sludge or form emulsion together with a heavy
ingredient such as a resin, or the like, and moisture.
Particularly, in the case in which the asphaltene is sunk as the
solid particle, the asphaltene present in an emulsion form is mixed
with another crude oil or is applied with thermal hysteresis, such
that resins in the vicinity of the asphaltene are separated.
Therefore, a shape of the asphaltene is changed into a solid
shape.
[0020] In addition, the crude oil sludge may further include water
regardless of a kind of crude oil. The water is included in the
crude oil sludge to form a kind of film in the vicinity of the
asphaltene. The asphaltene is three-dimensionally bridged and other
reins are solvated, such that the film may be a cause of allowing
the asphaltene to form the emulsion without being phase-separated
from a crude oil component. Therefore, the asphaltene having an
emulsion shape is a component that is the most difficult to be
separated in processing the-crude oil sludge, and it is difficult
to separate the asphaltene having the emulsion shape by
centrifugation, or the like.
[0021] Although the step a) according to the present invention may
be changed depending on compositions of the crude oil and the
sludge, it may be performed by any one or two or more selected
among a mechanical separating method such as a filtering method
using a filter, or the like, an agitating method, a manual method
(method of discharging the sludge to the outside of the tank using
a person or a machine), or the like, a. thermal separating method
of dissolving and pulverizing the sludge using heated crude oil or
hot water, a solvent extracting method of injecting a solvent or a
chemical dissolving the sludge into the tank to provide fluidity to
the sludge, a sound wave separating method, and a chemical
separating method.
[0022] Next, the recovered sludge is subjected to a step of
separating the sludge into the recovery oil, the water, and the
sediment like the step b), such that only the recovery oil may be
recovered.
[0023] According to the present invention, in the step b), a
separating method is not limited, but may be selected among various
methods depending on a composition of the sludge and a method of
removing the sludge. As an example, as disclosed in Korean Patent
No. 10-0475172, the sludge stations at a temperature of 60.degree.
C. or more, preferably, 60 to 130.degree. C., thereby making it
possible to phase-separate the sediment and the water from the
recovery oil. Here, the reason why the sludge is heated is that
viscosity of the sludge is decreased, such that a removal rate of
the sediment is improved. In addition, an additive such as a
dispersing agent, or the like, may be additionally injected, if
necessary. Meanwhile, this process may be performed in the crude
oil tank or be performed in a separate storage space connected to
the crude oil tank. Alternatively, as disclosed in Japanese Patent
Laid-Open Publication No. 2012-229403, a method of heating the
sludge to evaporate the recovery oil included in the sludge and
then recovering the recovery oil through cooling may also be
performed.
[0024] The recovery oil separated according to the exemplary
embodiment of the present invention may be recycled through a step
of mixing the recovery oil with the crude oil and performing the
fractional distillation on the mixture of the recovery oil and the
crude like the step c). In more detail, in the step c) according to
the present invention, the crude oil and the recovery oil may be
mixed with each other by any one or two or more selected among c1)
a method of mixing the recovery oil with the crude oil using a line
mixer and transferring the mixture to a charge pump; c2) a method
of periodically mixing the recovery oil with the crude oil and
transferring the mixture to the charge pump; and c3) a method of
mixing the recovery oil with the crude oil passing through the
charge pump and transferring the mixture to a desalter, and the
fractional distillation may be performed on the mixture of the
recovery oil and the crude oil.
[0025] Among them, c1) may further include c1-1) a step of mixing
the recovery oil with the crude oil using the line mixer; and c1-2)
a step of transferring the crude oil mixed with the recovery oil to
the charge pump.
[0026] This will be described in more detail with reference to FIG.
1. The recovery oil separated from the water and the sediment
through the phase separation may be mixed with the crude oil
passing through the charge pump as illustrated in and then pass
through the line mixer. The crude oil passing through the line
mixer to thereby be sufficiently mixed with the recovery oil may be
again supplied to the charge pump as illustrated in and be then
transferred to a crude distillation unit (CDU) process. However, in
order to more smoothly mix the recovery oil and the crude oil with
each other, the crude oil passing through a process of may be again
sent to a process of and be circulated. In addition, in a
circulation process, the recovery oil is continuously injected,
such that a process of mixing the recovery oil and the crude oil
with each other through the line mixer simultaneously with
circulating the crude oil may be continuously performed.
[0027] In addition, crude oil stored in the crude oil tank rather
than a crude oil charge tank may be mixed by the same method.
First, the recovery oil manufactured through the phase separation
may be mixed with the crude oil in the crude oil tank, as
illustrated in , and then pass through the line mixer. The crude
oil passing through the line mixer to thereby be sufficiently mixed
with the recovery oil may be again transferred to the crude oil
tank, as illustrated in , pass through the crude oil charge tank
and the charge pump, and be then transferred to the crude
distillation unit process. In addition, the crude oil with which
the recovery oil of is mixed may be sent to a process of in which
it is again mixed with the recovery oil and be circulated. In this
circulation process, the recovery oil is continuously injected,
such that a process of mixing the recovery oil and the crude oil
with each other through the line mixer simultaneously with
circulating the crude oil may be continuously performed.
[0028] In the method c1) according to the exemplary embodiment of
the present invention, the number of circulations is not limited,
and a kind, a size, a form, and the number of line mixers are not
limited. As an example, several members may be disposed in the line
mixer to adjust a flow velocity in the line mixer, and static
mixers and Sulzer mixers may be alternately mounted in the line
mixer.
[0029] In the method c1) according to the exemplary embodiment of
the present invention, processes of to may be simultaneously
performed. That is, the recovery oil phase-separated from the
sludge and the crude oil coming from the crude oil tank may be
mixed with as illustrated in {circle around (3)}, pass through the
line mixer, and be sent to . The crude oil passing through the line
mixer is not directly sent from the crude oil tank to the crude oil
charge tank, but may be circulated as in the process of . In
addition, the crude oil subjected to the processes of and may be
transferred from the crude oil tank to the crude oil charge tank
and the charge pump, be sent to a front end of the line mixer
through the process of to thereby be again mixed with the recovery
oil, and pass through the line mixer and be then sent to a front
end of the charge pump as illustrated in . Even in this case, the
crude oil passing through the charge pump is not directly sent to
the crude distillation unit process, but may be sent to the process
of and be again circulated.
[0030] The method c2) according to the exemplary embodiment of the
present invention is a method of adjusting a period in which the
crude oil and the recovery oil are mixed with each other at the
time of being mixed with each other. Since the recovery oil
generally has a very high pour point, it is changed into a
gel-phase at the time of being mixed with the crude oil at room
temperature. The gel-phase recovery oil may not pass through a
strainer used to filter impurities in front of the charge pump.
[0031] In the case in which the recovery oil is continuously mixed
with the crude oil, there is a risk that the strainer will be
clogged by the gel-phase recovery oil. In the method c2) according
to the exemplary embodiment of the present invention, a period in
which the recovery oil is supplied is adjusted at the time of
mixing the crude oil and the recovery oil with each other, thereby
making it possible to solve a phenomenon that the strainer in front
of the charge pump is clogged. That is, although the gel-phase
recovery oil may remain in the strainer without passing through the
strainer, only the crude oil passes through the strainer during a
period in which injection of the recovery oil is stopped, such that
the recovery oil strained by the strainer may be cleaned and pass
through the strainer by a flow of the crude oil.
[0032] A step c2) will be described below with reference to FIG. 2.
The recovery oil phase-separated and generated from the sludge is
mixed with the crude oil stored in the crude oil charge tank. Here,
a position at which the recovery oil is injected is in front of the
charge pump, and the recovery oil may be directly mixed with the
crude oil without introducing the line mixer. A mixing period of
the recovery oil may be freely changed depending on compositions of
the sludge and the recovery oil, fluidity of the recovery oil, and
the like, and a period in which the supply of the recovery oil is
stopped for 0.2 to 1 hour may be present after the recovery oil is
injected for 0.5 to 3 hours. That is, in order to clean the
recovery oil remaining in the strainer without passing through the
strainer due to the injection of the recovery oil, the period in
which the supply of the recovery oil is stopped for 0.2 to 1 hour
is present.
[0033] The method c3) according to the exemplary embodiment of the
present invention is a method of securing fluidity of the recovery
oil by preheating the crude oil at the time of mixing the crude oil
and the recovery oil with each other.
[0034] Generally, when the crude oil is fractionally distilled, it
is heated to 340 to 360.degree. C. to thereby be divided into
liquefied petroleum gas (LPG), gasoline, naphtha, kerosene, diesel,
heavy oil, and the like, based on a boiling point. Here, in order
to recover thermal energy applied to a distillation column, a heat
exchanger (preheater, preheat exchanger, or the like) is disposed
to heat the crude oil before being desalted. When the crude oil is
preheated through the heat exchanger, the crude oil having a room
temperature or a temperature slightly higher than the room
temperature is preheated to a temperature of 100.degree. C. or
more. Since this preheating temperature exceeds a pour point
(70.degree. C.) of the recovery oil, as soon as the recovery oil is
mixed with the crude oil, it has high fluidity, such that the
recovery oil and the crude oil may be uniformly mixed with each
other.
[0035] FIG. 3 illustrates the method c3) according to the exemplary
embodiment of the present invention. The recovery oil
phase-separated and generated from the sludge may be injected into
and mixed with the crude oil passing through the preheater. Here,
the crude oil passing through the preheater may be preheated to a
temperature of the pour point or more of the recovery oil,
preferably, temperature of 90 to 150.degree. C. In addition, the
recovery oil may be periodically injected as in c2) or be
continuously injected, and the crude oil may pass through the
desalter and be then preheated through the preheater in order for
the recovery oil and the crude oil to be more uniformly mixed with
each other.
[0036] In the present invention, 0.1 to 2 parts by weight of
recovery oil may be mixed with 100 parts by weight of crude oil. In
the case in which parts by weight of mixed recovery oil exceeds 2
parts by weight, the recovery oil is not smoothly mixed with the
crude oil, such that it is difficult to secure fluidity of the
recovery oil, and impurities in the recovery oil occlude facilities
such as a heating furnace, a pipe, and the like, or are accumulated
on inner walls of the facilities, such that process efficiency may
be significantly decreased.
[0037] In addition, in the recycling method of recovery oil
according to the exemplary embodiment of the present invention,
additives such as a neutralizing agent, an emulsification
preventing agent, a metal pollution removing agent, a stabilizer,
and the like, may be further included, in some cases. Particularly,
when an excessively large amount of caustic material is present, a
process of stabilizing and separating an asphaltene-water mixture
may be hindered due to a fatty acid, and in the case in which the
crude oil and the water are excessively strongly mixed with each
other, emulsion that is difficult to be decomposed may be formed.
Therefore, it is preferable that the neutralizing agent and the
emulsification preventing agent that may adjust stability of the
asphaltene-water mixture are added. These additives may be injected
in the middle of a process, and may be injected in any step without
departing the scope of the present invention.
[0038] In addition, in the recycling method of recovery oil
according to the exemplary embodiment of the present invention, a
condensate may be further mixed at the time of mixing the crude oil
and the recovery oil with each other.
[0039] The condensate according to the present invention means a
liquid-phase hydrocarbon mixture obtained through a condensing
process of condensing high boiling point materials by a physical
phase change by compressing and cooling a gas mixture and having
carbons of 1 to 7. Since the condensate is a hydrocarbon having a
small number of carbons, it may have low viscosity to improve
mixing efficiency between the recovery oil and the crude oil.
[0040] The recycling method of recovery oil according to present
invention will be described in more detail through Inventive
Examples and. Comparative Examples. However, the following
Inventive Examples and Comparative Examples are only examples for
describing the present invention in more detail, and the present
invention is not limited by Inventive Examples and Comparative
Examples.
[0041] Components of materials and physical property measuring
methods used in Inventive Examples and Comparative Examples are as
follows.
[0042] (Crude Oil)
[0043] Properties and mixing ratios of crude oils through Inventive
Examples are illustrated in the following Tables 1 and 2.
TABLE-US-00001 TABLE 1 Division Crude Oil 1 Crude Oil 2 Property
Specific Gravity 0.8234 0.8189 (15/4.degree. C.) Sulfur, wt. % 1.5
1.5 Nitrogen, ppm 1447 1365 Water and Sediment, 0.05 0.05 vol. %
Carbon Residue, 3.91 3.92 wt. % Salinity, ptb 5.7 5.8 Iron, ppm 7 2
Vanadium, ppm 25 26 Nickel, ppm 8 7 Yield .sup. C5~75.degree. C.
4.4 4.7 (wt. %) 75~155.degree. C. 12.5 13.6 155~235.degree. C. 17.2
17.5 235~350.degree. C. 17.1 16 350~360.degree. C. 1.3 1.2
360.degree. C.~ 47.7 46.9
TABLE-US-00002 TABLE 2 Mixing Ratio (vol. %) Division KWT ARH RAS
MPC SNP TNG KFC ROD MEL SRN Sum Crude Oil 1 29.2 19.1 9.4 12.5 4.1
3.4 12.7 3.6 1.4 4.5 100.0 Crude Oil 2 26.5 19.8 8.8 12.1 3.3 3.3
14.9 2.8 3.6 4.8 100.0
[0044] (Sludge and Recovery Oil After Being Phase-Separated)
[0045] Properties of the sludge and the recovery oil after a
phase-separation process are illustrated in the following Table
3.
TABLE-US-00003 TABLE 3 Division Sludge Recovery Oil Property
Specific Gravity Measurement 0.8700 (15/4.degree. C.) is impossible
Pour Point, .degree. C. Measurement 70 is impossible Carbon
Residue, -- 5.85 wt. % Salinity, ptb -- 56 Iron, mg/kg 2,983 1,997
Vanadium, mg/kg 27 27 Nickel, mg/kg 8 10 Yield, .sup. C5~75.degree.
C. 1.2 1.6 wt. % 75~155.degree. C. 7.4 9.2 155~235.degree. C. 8.9
12.7 235~350.degree. C. 9.2 15.3 350~360.degree. C. 0.7 1.1
360.degree. C.~ 72.6 60.2
[0046] (Property of Mixed Oil)
[0047] Physical properties of mixed oil used in Inventive Examples
were measured by the following method.
[0048] Sulfur: A total of sulfur was measured using a monochromatic
wavelength-dispersive X-ray fluorescence (MWDXRF) spectrometry
depending on ASTM D7039 (Standard Test Method for Sulfur in
Gasoline and Diesel Fuel by Monochromatic Wavelength Dispersive
X-ray Fluorescence Spectrometry).
[0049] Nitrogen: A content was calculated by burning a sample at a
temperature of 1,000.degree. C. using an element analyzer (EA-CHNS)
to decompose the sample into gas and measuring thermal conductivity
of the gas.
[0050] Micro-Carbon Residue (MCR): An amount of carbon residue
remaining after evaporation and thermal decomposition of a
substrate was measured depending on ASTM D450.
[0051] Metal Content: Each of contents of iron, vanadium, and
nickel was measured using an inductively coupled plasma-atomic
emission spectrometer (ICP-AES).
[0052] Salinity: Salinity was measured using a salt analyzer
depending on ASTM D3230.
[0053] (Yield)
[0054] A sample was measured using a gas chromatography frame
ionization detector (GC-FID).
INVENTIVE EXAMPLE 1
[0055] 1,400 tons of sludge collected in a crude oil charge tank
was transferred to a centrifugation tank of 80.degree. C. and was
phase-separated. Water and sediment were separately separated from
the sludge through the phase separation, and 1,000 tons of
remaining recovery oil was recovered.
[0056] Separately from the above-mentioned process, Crude Oil 1 in
Table 1 stored in the crude oil charge tank passed through a charge
pump and was then mixed with the recovery oil. Here, a mixing
amount was illustrated in the following Table 4, and the crude oil
and the recovery oil passed through a line mixer immediately after
they were mixed with each other, such that they were uniformly
mixed with each other. The crude oil of which mixing is ended was
again supplied to the charge pump and was sent to a CDU process to
thereby be crude-distilled. Here, a crude oil sample was collected,
and properties of mixed oil of the crude oil and the recovery oil
and yields depending on a fractional distillation temperature were
measured and illustrated in the following Table 4.
INVENTIVE EXAMPLE 2
[0057] 1,400 tons of sludge collected in a crude oil charge tank
was transferred to a centrifugation tank of 80.degree. C. and was
phase-separated. Water and sediment were separately separated from
the sludge through the phase separation, and 1,000 tons of
remaining recovery oil was recovered.
[0058] Separately from the above-mentioned process, Crude Oil 2 in
Table 1 stored in the crude oil charge tank passed through a charge
pump and was then mixed with the recovery oil. Here, a mixing
amount was illustrated in the following Table 4, and the crude oil
and the recovery oil passed through a line mixer immediately after
they were mixed with each other, such that they were uniformly
mixed with each other. The crude oil of which mixing is ended was
again supplied to the charge pump and was sent to a CDU process to
thereby be crude-distilled. Here, a crude oil sample was collected,
and properties of mixed oil of the crude oil and the recovery oil
and yields depending on a fractional distillation temperature were
measured and illustrated in the following Table 4.
COMPARATIVE EXAMPLE 1
[0059] Fractional distillation was performed using the same method
as that of Inventive Example 1 except that the recovery oil is not
mixed. Here, a crude oil sample was collected, and properties and
yields depending on a fractional distillation temperature were
measured and illustrated in the following Table 4.
COMPARATIVE EXAMPLE 2
[0060] Fractional distillation was performed using the same method
as that of Inventive Example 2 except that the recovery oil is not
mixed. Here, a crude oil sample was collected, and properties and
yields depending on a fractional distillation temperature were
measured and illustrated in the following Table 4.
TABLE-US-00004 TABLE 4 Inventive Inventive Inventive Inventive
Inventive Inventive Comparative Comparative Division Example 1-1
Example 1-2 Example 1-3 Example 2-1 Example 2-2 Example 2-3 Example
1 Example 2 Mixing Crude Oil 100 100 100 100 100 100 100 100
Condition (mL) Recovery 0.5 1 2 0.5 1 2 0 0 Oil (g) Property
Sulfur, 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 wt. % Nitrogen, 1384 1459
1400 1354 1277 1282 1447 1365 ppm Water and 0.05 0.05 0.05 0.05
0.05 0.05 0.05 0.05 Sediment, vol. % Carbon 3.87 4.31 3.79 3.76
3.74 3.84 3.91 3.92 Residue, wt. % Salinity, 5.8 6.5 6.7 5.8 6.4
6.8 5.7 5.8 ptb Iron, ppm 18 23 32 11 19 32 7 2 Vanadium, 25 26 27
25 26 25 25 26 ppm Nickel, 7 7 8 8 8 8 8 7 ppm Yield C5~75.degree.
C. 4.4 3.9 5.5 5.2 5.8 5.8 4.4 4.7 (wt. %) 75~155.degree. C. 11.7
11.8 12.1 12.1 12.6 12.6 12.5 13.6 155~235.degree. C. 17.8 17.8 17
17.7 17.4 16.6 17.2 17.5 235~350.degree. C. 17.2 17.2 16.1 15.8
15.1 14.6 17.1 16 350~360.degree. C. 1.3 1.3 1.1 1.2 1.1 1.1 1.3
1.2 360.degree. C.~ 47.6 48 48.3 48.0 48.0 49.3 47.7 46.9
[0061] As illustrated in Table 4, it may be appreciated that crude
oil subjected to the recycling method according to the present
invention maintains similar compositions without increasing
components other than iron and salinity in a property. Although an
oil separation time tends to be increased due to an increase in a
content of salinity, a decrease in oil separation efficiency may be
prevented by injecting the emulsification preventing agent. In
addition, it may be appreciated that similar numerical values are
shown regardless of a temperature in terms of a yield, such that
even though the recovery oil is mixed, it may be effectively
recycled without having a large influence on the properties and the
yields.
[0062] In the recycling method of recovery oil according to the
present invention in which the recovery oil separated from the
sludge accumulated in the crude oil tank is recycled, a limitation
in a storage feature of the crude tank depending on the
accumulation of the sludge may be solved. In addition,
disadvantages of the recovery oil such as a high pour point, a low
flash point, and a high content of impurities are overcome, and
fractional distillation is performed, thereby making it possible to
expect a profitability improving effect. Further, a process cost
decrease effect depending on processing of the sludge may be
accomplished, and a waste processing cost may be significantly
decreased.
[0063] Although the exemplary embodiments of the present invention
have been described hereinabove, various modifications and
alterations and equivalents of the present invention are possible,
and the exemplary embodiments may be appropriately modified and
similarly applied. Therefore, contents described in the exemplary
embodiments do not limit the scope of the present invention as
defined by the claims.
* * * * *