U.S. patent application number 17/209952 was filed with the patent office on 2022-06-16 for solvent deasphalting dearomatization process for heavy oil upgradation.
The applicant listed for this patent is BHARAT PETROLEUM CORPORATION LTD.. Invention is credited to Seetaram Chebrolu, Rajeev Kumar, Sreedevi Upadhyayula, Ravi Kumar Voolapalli.
Application Number | 20220186126 17/209952 |
Document ID | / |
Family ID | |
Filed Date | 2022-06-16 |
United States Patent
Application |
20220186126 |
Kind Code |
A1 |
Kumar; Rajeev ; et
al. |
June 16, 2022 |
SOLVENT DEASPHALTING DEAROMATIZATION PROCESS FOR HEAVY OIL
UPGRADATION
Abstract
An aspect of the present disclosure relates to a process for
solvent deasphalting dearomatization, said process including:
effecting deasphaltenation of a heavy oil feed by contacting the
feed with a paraffinic rich solvent, optionally, in presence of a
FCC catalyst to obtain a deasphalted oil rich stream, said
paraffinic rich solvent being untreated naphtha; contacting the DAO
rich stream with a second solvent to obtain a raffinate stream rich
in non-asphaltene and non-aromatic contents and a solvent rich
stream; contacting the raffinate stream with water in a first
decanter to obtain a first stream rich in aromatic-lean fraction
and a second stream rich in the second solvent and water;
subjecting the first stream to distillation to recover the
paraffinic rich solvent and to obtain deasphalted oil; contacting
the solvent rich stream with water in a second decanter to obtain
an aromatic rich fraction and a third stream rich in the second
solvent and water; and subjecting the second stream and the third
stream to distillation to recover the second solvent and water.
Inventors: |
Kumar; Rajeev; (Mumbai,
IN) ; Chebrolu; Seetaram; (Mumbai, IN) ;
Voolapalli; Ravi Kumar; (Mumbai, IN) ; Upadhyayula;
Sreedevi; (New Delhi, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BHARAT PETROLEUM CORPORATION LTD. |
Mumbai |
|
IN |
|
|
Appl. No.: |
17/209952 |
Filed: |
March 23, 2021 |
International
Class: |
C10G 21/02 20060101
C10G021/02; B01J 35/10 20060101 B01J035/10; C10G 21/20 20060101
C10G021/20 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 15, 2020 |
IN |
202021054421 |
Claims
1. A process for solvent deasphalting dearomatization for heavy oil
upgradation, said process comprising: (a) effecting
deasphaltenation of a heavy oil feed by contacting the feed with a
paraffinic rich solvent in presence of a Fluid Catalytic Cracking
(FCC) catalyst to obtain a deasphalted oil (DAO) rich stream, said
paraffinic rich solvent being untreated naphtha; (b) contacting the
deasphalted oil (DAO) rich stream with a second solvent to obtain a
raffinate stream rich in non-asphaltene and non-aromatic contents
and a solvent rich stream; (c) contacting the raffinate stream with
water in a first decanter to obtain a first stream rich in
aromatic-lean fraction and a second stream rich in the second
solvent and water; (d) subjecting the first stream to distillation
to recover the paraffinic rich solvent and to obtain deasphalted
oil; (e) contacting the solvent rich stream with water in a second
decanter to obtain an aromatic rich fraction and a third stream
rich in the second solvent and water; and (f) subjecting the second
stream and the third stream to distillation to recover the second
solvent and water.
2. The process as claimed in claim 1, wherein said second solvent
is selected from N-methyl-2-pyrrolidone (NMP), water and
combinations thereof, and wherein the deasphalted oil (DAO) rich
stream is contacted with the second solvent in a weight ratio
ranging from 4:1 to 1:4.
3. The process as claimed in claim 1, wherein the weight ratio of
the solvent to the feed (S:F) is between 1:1 to 30:1.
4. The process as claimed in claim 1, wherein said Fluid Catalytic
Cracking (FCC) catalyst is a spent FCC catalyst, said spent FCC
catalyst having BET surface area ranging from 100 m.sup.2/g to 200
m.sup.2/g, micro pore volume ranging from 0.02 cc/g to 0.08 cc/g,
microporous area ranging from 60 m.sup.2/g to 180 m.sup.2/g, and
matrix surface area ranging from 40 m.sup.2/g to 80 m.sup.2/g.
5. The process as claimed in claim 1, wherein the step of
deasphaltenation of a heavy oil feed is effected in presence of the
Fluid Catalytic Cracking (FCC) catalyst at an amount ranging from
0.5 wt. % to about 15 wt. %.
6. The process as claimed in claim 1, wherein the recovered
paraffinic rich solvent is reused for effecting deasphaltenation of
heavy oil feed, and wherein the recovered second solvent is reused
for effecting dearomatization of deasphalted oil rich stream.
7. The process as claimed in claim 1, wherein the step of
deasphaltenation is effected by contacting the feed with untreated
naphtha in presence of the spent Fluid Catalytic Cracking (FCC)
catalyst to obtain the deasphalted oil (DAO) rich stream, and
wherein the weight ratio of the solvent to the feed (S:F) is 20:1
and the amount of spent Fluid Catalytic Cracking (FCC) catalyst is
5 wt. %.
8. A process for solvent deasphalting dearomatization for heavy oil
upgradation, said process comprising: (a) effecting
deasphaltenation of a heavy oil feed by contacting the feed with a
paraffinic rich solvent to obtain a deasphalted oil (DAO) rich
stream, said paraffinic rich solvent being untreated naphtha; (b)
contacting the deasphalted oil (DAO) rich stream with a second
solvent to obtain a raffinate stream rich in non-asphaltene and
non-aromatic contents and a solvent rich stream; (c) contacting the
raffinate stream with water in a first decanter to obtain a first
stream rich in aromatic-lean fraction and a second stream rich in
the second solvent and water; (d) subjecting the first stream to
distillation to recover the paraffinic rich solvent and to obtain
deasphalted oil; (e) contacting the solvent rich stream with water
in a second decanter to obtain an aromatic rich fraction and a
third stream rich in the second solvent and water; and (f)
subjecting the second stream and the third stream to distillation
to recover the second solvent and water.
9. The process as claimed in claim 8, wherein the weight ratio of
the solvent to the feed (S:F) is between 1:1 to 30:1.
10. The process as claimed in claim 8, wherein the deasphalted oil
(DAO) rich stream is contacted with the second solvent in a weight
ratio ranging from 4:1 to 1:4, said second solvent being selected
from N-methyl-2-pyrrolidone (NMP), water and combinations thereof.
Description
CROSS REFERENCE TO RELATED APPLICATION(S)
[0001] This application is related to and claims priority to Indian
Patent Application No. 202021054421 filed on Dec. 15, 2020, the
contents of which are incorporated by reference herein.
TECHNICAL FIELD
[0002] The present disclosure pertains to the technical field of
heavy oil upgradation. In particular, the present disclosure
relates to a solvent deasphalting dearomatization (SD-A.sup.2)
process for heavy oil upgradation.
BACKGROUND OF THE INVENTION
[0003] Background description includes information that may be
useful in understanding the present invention. It is not an
admission that any of the information provided herein is prior art
or relevant to the presently claimed invention, or that any
publication specifically or implicitly referenced is prior art.
[0004] Forecast of oil production showing continuous increase in
heavy or extra-heavy oils. They are available at low cost. In order
to increase gross refinery margin, increasing heavy oil diet to
refinery feedstock is an opportunity with operational challenges.
Asphaltene is the common problem especially when heavy oil fraction
increases in the refinery feedstock. High asphaltene content causes
flocculation and/or precipitation, instability, and incompatibility
which in turn can affect the desalter operation by strong water
emulsions with asphaltene, fouling in heat exchangers means excess
fuel firing and emissions, and/or coking issues during processing.
The severity increases as the feedstock become heavier. In the
current practices, the impact of asphaltene are diluted by light
oils, checking the blend compatibility of light and heavy oils and
accordingly crude mixed are processed. The problem is more complex
with increasing number of blending streams in crude mix. If
precipitation happens beyond the specified limit, refineries can
lose more than the advantage of purchasing the heavy or opportunity
crudes. It is noteworthy to mention that maintaining asphaltene
compatibility in refining is a temporary solution. Deasphalting
(i.e., removal of asphaltene from feedstock) can be the sustenance
solution for heavy oils.
[0005] Solvent deasphalting (SDA) technology uses light hydrocarbon
alkanes as solvent (e.g., propane, butane, pentane, heptane or
naphtha) to separate asphaltene-lean phase known as deasphalted oil
(DAO) and asphaltene-rich phase known as pitch. SDA processes is
the need for refining industry and will continue to be so until at
least the end of the 21.sup.st century. The most commonly known
technologies are: ROSE (Residuum Oil Supercritical Extraction by
KBR), LEDA (Low Energy Deasphalting, by Foster Wheeler), Demex
technologies by UOP/Foster Wheeler, and Solvahl process by IFP
(France)/Axens. The subject has been so important for oil majors,
there are several patents on this technology disclosing different
process schemes such as U.S. Pat. No. 4,239,616 (1979) discloses
deasphalting of heavy oil containing asphaltene up to 18 wt % with
paraffins solvent (C3-C9), S/F ratio 10-20; U.S. Pat. No. 4,421,639
(1983) discloses deasphalting using C3 solvent with the objective
of an energy efficient continuous recovery of solvent; U.S. Pat.
No. 4,428,824 (1984) used C3-C4 solvent, S/F ratio 5-12 and the
primary focus was on visbreaking a DAO and subsequently re-blending
the recovered asphaltene fraction to produce a product of low
viscosity and pour point and requiring less cutter-stock oil as
compared to conventional visbreaking processes; U.S. Pat. No.
4,454,023 (1984) discloses integration of visbreaking and SDA using
C5 solvent, S/F ratio 12 with the atmospheric residue as feedstock;
US pat. 4572781 (1986) discloses deasphalting with C5-C12 solvent,
S/F ratio 2-12 with the intent of separating substantially dry
asphaltenes of high softening point from heavy hydrocarbon
material; U.S. Pat. No. 4,810,367 (1989) discloses deasphalting
using C3-05 and the primary focus was to develop two stages of
precipitation from the feedstock of an asphaltene fraction using
light and heavy solvents; U.S. Pat. No. 5,919,355 (1999) discloses
a solvent whose critical temperature is Tc to a hydrocarbon feed
containing asphaltenes and atmospheric distillate having fractions
that boil above about Tc such that said feed is separated into a
substantially solvent-free product stream; U.S. Pat. No. 6,533,925
(2003) discloses mixture of solvents containing C3-C7 wherein C6
& C7 is less than 20wt % and the focus was on heat integration
of a solvent deasphalting process with a gasification process; U.S.
Pat. No. 7,381,320 (2008) is an extension of ROSE process which
discloses the sequence of aromatics solvents following by aliphatic
solvents. DAO was subjected to FCCU and asphaltene-rich streams
sent to Bitumen, Gasification DCU etc. depending upon
configuration; U.S. Pat. No. 7,597,794 (2009) discloses
deasphalting using C4-C6, S/F ratio=1.5/1 to 5/1; with super
critical solvent recovery process for deep separation of a heavy
oil with coupled post-extraction adjustable asphalt residue
granulation; U.S. Pat. No. 7,749,378 (2010) & US Pat. US
2007/0125686 (2007) discloses deasphalting of bitumen and sand
bitumen respectively as feedstock for upgrading in bitumen; U.S.
Pat. No. 00,243,518 (2010) discloses deasphalting of Gas Oil from
slurry hydrocracking using C4-C5; U.S. Pat. No. 00,300,934 (2010)
discloses an integration of slurry phase hydrocracking and SDA
using propane, and solvent recovery under supercritical conditions;
U.S. Pat. No. 0,264,247 (2013) & U.S. Pat. No. 0,026,074 (2013)
discloses heavy oil upgradation using gasoline (C5 to C12) &
Naphtha (C5-C12) respectively; and US Pat. 20150152027A1 discloses
deasphalting with blend of natural condensate and naphtha as
solvent for deasphalting and further proposed an integration of SDA
and FCC process for increasing light olefins production, contents
whereof are incorporated herein in its entirety by way of
reference.
[0006] Although lighter solvents C3-C5 have proven their
performance in deasphalting, the current literature trends of SDA
technology indicate that the blend of n-alkanes and heavier
paraffins like C5-C12 (including various types of naphtha,
gasoline, treated naphtha etc.) can perform as economically viable
solvents. This, of course, needs consideration of the types of
feedstock, targeted DAO & pitch qualities and the available
refinery configuration and the primary objective for selecting the
paraffin range of solvent. Among all n-alkane solvents, propane is
the most suitable solvent for deasphalting. In literature, the
order of preference of solvents reported
is--propane>butane>pentane>hexane>heptane. It is known
that n-butane and i-butane are good for deasphalting heavy oil,
however, there is loss of selectivity when feed becomes lighter,
pentane is less selective for metals and CCR removal. Therefore,
selection of solvents has always been guided by the feedstock
characteristics and the targeted quality of deasphalted oil (DAO);
even this holds good for higher carbon range paraffinic solvents.
SDA intent is to separate the DAO and pitch, the former being
usually fed to fluid catalytic cracking unit (FCCU) or
hydrocracking unit (HCU) and the pitch is largely used as bending
stock for bitumen, gasification or delayed coker feedstock.
[0007] Despite rigorous research in the field of heavy oil
upgradation for the past 50 years, there remains a long standing
need for an economical and commercially viable process for heavy
oil upgradation. The present disclosure provides an improved
process for heavy oil upgradation that does not necessarily make
use of conventional organic solvents such as propane, butane,
pentane, hexane, heptane and treated naphtha.
[0008] All publications herein are incorporated by reference to the
same extent as if each individual publication or patent application
were specifically and individually indicated to be incorporated by
reference. Where a definition or use of a term in an incorporated
reference is inconsistent or contrary to the definition of that
term provided herein, the definition of that term provided herein
applies and the definition of that term in the reference does not
apply.
OBJECTS
[0009] It is an object of the present disclosure to provide an
improved process for heavy oil upgradation that is not dependent on
utilization of conventional costly solvents such as propane,
butane, pentane, hexane, heptane and treated naphtha.
[0010] It is an object of the present disclosure to provide an
improved process for heavy oil upgradation that is significantly
economical and commercially viable.
[0011] It is an object of the present disclosure to provide an
improved process for heavy oil upgradation that can take up
incompatible heavy oil streams as feed.
SUMMARY
[0012] The present disclosure pertains to the technical field of
heavy oil upgradation. In particular, the present disclosure
relates to a solvent deasphalting dearomatization (SD-A.sup.2)
process for heavy oil upgradation.
[0013] The present disclosure is on the premise of surprising
discovery by inventors of the present invention that execution of
dearomatization process post solvent deasphalting of heavy oil
affords utilization of untreated naphtha as a solvent, which is
significantly economical solvent as compared to treated naphtha and
such other conventional solvents like propane, butane, pentane,
hexane and heptane, wherein the untreated naphtha upon undergoing
dearomatization results in in-situ (or in-line) generation of
treated naphtha that can be recovered and reused again in
deasphaltenation of heavy oils. Further, the process of the present
disclosure is able to take up incompatible heavy oil streams as
feed in stark contrast to conventional processes, affording greater
flexibility and huge cost savings. Particularly, the process of the
present disclosure affords high flexibility in the process scheme
for using different grades of naphtha for producing different
grades of deasphalted oil with same feedstock (or feed). It is also
suitable to manage feed variations with varying naphtha quality to
produce similar quality of deasphalted oil in SD-A2 process scheme.
Due to flexibility in the process, the process can be easily
integrated with other refinery units wherever heavy oils are
produced and need upgradation for asphaltene and aromatics removal
for value addition.
[0014] Accordingly, an aspect of the present disclosure relates to
a process for solvent deasphalting dearomatization for heavy oil
upgradation, said process including: (a) effecting deasphaltenation
of a heavy oil feed by contacting the feed with a paraffinic rich
solvent in presence of a Fluid Catalytic Cracking (FCC) catalyst to
obtain a deasphalted oil (DAO) rich stream, said paraffinic rich
solvent being untreated naphtha; (b) contacting the deasphalted oil
(DAO) rich stream with a second solvent to obtain a raffinate
stream rich in non-asphaltene and non-aromatic contents and a
solvent rich stream, said second solvent being
N-methyl-2-pyrrolidone (NMP), water or combinations thereof; (c)
contacting the raffinate stream with water in a first decanter to
obtain a first stream rich in aromatic-lean fraction and a second
stream rich in the second solvent and water; (d) subjecting the
first stream to distillation to recover the paraffinic rich solvent
and to obtain deasphalted oil; (e) contacting the solvent rich
stream with water in a second decanter to obtain an aromatic rich
fraction and a third stream rich in the second solvent and water;
and (f) subjecting the second stream and the third stream to
distillation to recover the second solvent and water. In an
embodiment, the recovered paraffinic rich solvent is reused for
effecting deasphaltenation of heavy oil feed. In an embodiment, the
recovered second solvent is reused for effecting dearomatization of
deasphalted oil rich stream. In an embodiment, the weight ratio of
the solvent to the feed (S:F) is between 1:1 to 30:1. In an
embodiment, the Fluid Catalytic Cracking (FCC) catalyst is a spent
FCC catalyst. In an embodiment, the spent FCC catalyst has BET
surface area ranging from 100 m.sup.2/g to 200 m.sup.2/g, micro
pore volume ranging from 0.02 cc/g to 008 cc/g, microporous area
ranging from 60 m.sup.2/g to 180 m.sup.2/g, and matrix surface area
ranging from 40 m.sup.2/g to 80 m.sup.2/g. In an embodiment, the
process affords deasphalting dearomatization of incompatible heavy
oil streams. In an embodiment, the deasphalted oil (DAO) rich
stream is contacted with the second solvent in a weight ratio
ranging from 4:1 to 1:4. In an embodiment, the deasphalted oil
(DAO) rich stream is contacted with the second solvent in a weight
ratio of 1:1. In an embodiment, the step of deasphaltenation of a
heavy oil feed is effected in presence of the Fluid Catalytic
Cracking (FCC) catalyst at an amount ranging from 0.5 wt. % to
about 15 wt. %. In an embodiment, the step of deasphaltenation is
effected by contacting the feed with untreated naphtha in presence
of the spent Fluid Catalytic Cracking (FCC) catalyst to obtain the
deasphalted oil (DAO) rich stream, and wherein the weight ratio of
the solvent to the feed (S:F) is 20:1 and the amount of spent Fluid
Catalytic Cracking (FCC) catalyst is 5 wt. %.
[0015] Another aspect of the present disclosure relates to a
process for solvent deasphalting dearomatization for heavy oil
upgradation, said process comprising: (a) effecting
deasphaltenation of a heavy oil feed by contacting the feed with a
paraffinic rich solvent to obtain a deasphalted oil (DAO) rich
stream, said paraffinic rich solvent being untreated naphtha; (b)
contacting the deasphalted oil (DAO) rich stream with a second
solvent to obtain a raffinate stream rich in non-asphaltene and
non-aromatic contents and a solvent rich stream, said second
solvent being N-methyl-2-pyrrolidone (NMP), water or combinations
thereof; (c) contacting the raffinate stream with water in a first
decanter to obtain a first stream rich in aromatic-lean fraction
and a second stream rich in the second solvent and water; (d)
subjecting the first stream to distillation to recover the
paraffinic rich solvent and to obtain deasphalted oil; (e)
contacting the solvent rich stream with water in a second decanter
to obtain an aromatic rich fraction and a third stream rich in the
second solvent and water; and (f) subjecting the second stream and
the third stream to distillation to recover the second solvent and
water. In an embodiment, the recovered paraffinic rich solvent is
reused for effecting deasphaltenation of heavy oil feed. In an
embodiment, the recovered second solvent is reused for effecting
dearomatization of deasphaltenated oil rich stream. In an
embodiment, the weight ratio of the solvent to the feed (S:F) is
between 1:1 to 10:1. In an embodiment, the process affords
deasphalting dearomatization of incompatible heavy oil streams. In
an embodiment, the deasphalted oil (DAO) rich stream is contacted
with the second solvent in a weight ratio ranging from 4:1 to 1:4,
said second solvent being selected from N-methyl-2-pyrrolidone
(NMP), water and combinations thereof.
[0016] Various objects, features, aspects and advantages of the
inventive subject matter will become more apparent from the
following detailed description of preferred embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The accompanying drawings are included to provide a further
understanding of the present disclosure, and are incorporated in
and constitute a part of this specification. The drawings
illustrate exemplary embodiments of the present disclosure and,
together with the description, serve to explain the principles of
the present disclosure.
[0018] FIG. 1 illustrates an exemplary schematic showing a process
for solvent deasphalting dearomatization for heavy oil upgradation,
in accordance with embodiments of the present disclosure.
[0019] FIG. 2 illustrates an exemplary ASTM D86 distillation
profile of solvents for deasphalting process, in accordance with
embodiments of the present disclosure.
[0020] FIGS. 3A-3C illustrate exemplary Ternary phase diagrams of
Sulfolane (TMS), NMP (N-MET-01) & Tetra-Ethylene Glycol
(TETRA-01), in accordance with embodiments of the present
disclosure.
[0021] FIGS. 4A-4F illustrate exemplary graphs showing Distribution
coefficients of Sulfolane (TMS), N-methyl-2-pyrrolinone (NMP),
tetra-ethylene glycol (TETRA), tri-ethylene glycol (TRI), Furfural
and N-formylmorpholine (NFM), in accordance with embodiments of the
present disclosure.
[0022] FIGS. 5A-5F illustrate exemplary graphs showing selectivity
of TMS, NMP, TETRA, TRI, Furfural & NFM, in accordance with
embodiments of the present disclosure.
[0023] FIGS. 6A-6F illustrate exemplary graphs showing Performance
Index of TMS, NMP, TETRA, TRI, Furfural & NFM, in accordance
with embodiments of the present disclosure.
[0024] FIG. 7 illustrates an exemplary graph showing suitability of
feedstock for solvent deasphalting, in accordance with embodiments
of the present disclosure.
[0025] FIGS. 8A-8B illustrate exemplary graphs showing effect of
solvent types and solvent to oil ratio on DAO yield and Pitch yield
at 25.degree. C., in accordance with embodiments of the present
disclosure.
[0026] FIGS. 9A-9B illustrate exemplary graphs showing DAO quality
at S/F ratio: 20/1; T=25.degree. C. & t=2 hr: with regards
saturate, aromatics, resin & asphaltene and % Sulphur in DAO of
feed profile, in accordance with embodiments of the present
disclosure.
[0027] FIG. 10 illustrates an exemplary snippet showing pattern of
step-wise blending light into heavy and heavy into light at a 10%
increasing rate, in accordance with embodiments of the present
disclosure.
[0028] FIGS. 11A-11B illustrate exemplary graphs showing the effect
of spent catalyst addition with RN at different solvent to oil
ratio on DAO yield and Pitch yield at 25.degree. C., in accordance
with embodiments of the present disclosure.
[0029] FIG. 12 illustrates an exemplary graph showing quality of
DAO-I & DAO-II, in accordance with embodiments of the present
disclosure.
DETAILED DESCRIPTION
[0030] The following is a detailed description of embodiments of
the present invention. The embodiments are in such detail as to
clearly communicate the invention. However, the amount of detail
offered is not intended to limit the anticipated variations of
embodiments; on the contrary, the intention is to cover all
modifications, equivalents, and alternatives falling within the
spirit and scope of the present invention as defined by the
appended claims.
[0031] The present disclosure pertains to the technical field of
heavy oil upgradation. In particular, the present disclosure
relates to a solvent deasphalting dearomatization (SD-A.sup.2)
process for heavy oil upgradation.
[0032] Each of the appended claims defines a separate invention,
which for infringement purposes is recognized as including
equivalents to the various elements or limitations specified in the
claims. Depending on the context, all references below to the
"invention" may in some cases refer to certain specific embodiments
only. In other cases it will be recognized that references to the
"invention" will refer to subject matter recited in one or more,
but not necessarily all, of the claims.
[0033] Groupings of alternative elements or embodiments of the
invention disclosed herein are not to be construed as limitations.
Each group member can be referred to and claimed individually or in
any combination with other members of the group or other elements
found herein. One or more members of a group can be included in, or
deleted from, a group for reasons of convenience and/or
patentability.
[0034] Unless the context requires otherwise, throughout the
specification which follow, the word "comprise" and variations
thereof, such as, "comprises" and "comprising" are to be construed
in an open, inclusive sense that is as "including, but not limited
to."
[0035] Reference throughout this specification to "one embodiment"
or "an embodiment" means that a particular feature, structure or
characteristic described in connection with the embodiment is
included in at least one embodiment. Thus, the appearances of the
phrases "in one embodiment" or "in an embodiment" in various places
throughout this specification are not necessarily all referring to
the same embodiment. Furthermore, the particular features,
structures, or characteristics may be combined in any suitable
manner in one or more embodiments.
[0036] As used in the description herein and throughout the claims
that follow, the meaning of "a," "an," and "the" includes plural
reference unless the context clearly dictates otherwise. Also, as
used in the description herein, the meaning of "in" includes "in"
and "on" unless the context clearly dictates otherwise.
[0037] In some embodiments, the numbers expressing quantities of
ingredients, properties such as concentration, and so forth, used
to describe and claim certain embodiments of the invention are to
be understood as being modified in some instances by the term
"about." Accordingly, in some embodiments, the numerical parameters
set forth in the written description are approximations that can
vary depending upon the desired properties sought to be obtained by
a particular embodiment. In some embodiments, the numerical
parameters should be construed in light of the number of reported
significant digits and by applying ordinary rounding techniques.
Notwithstanding that the numerical ranges and parameters setting
forth the broad scope of some embodiments of the invention are
approximations, the numerical values set forth in the specific
examples are reported as precisely as practicable.
[0038] The recitation of ranges of values herein is merely intended
to serve as a shorthand method of referring individually to each
separate value falling within the range. Unless otherwise indicated
herein, each individual value is incorporated into the
specification as if it were individually recited herein.
[0039] The headings and abstract of the invention provided herein
are for convenience only and do not interpret the scope or meaning
of the embodiments.
[0040] All methods described herein can be performed in any
suitable order unless otherwise indicated herein or otherwise
clearly contradicted by context. The use of any and all examples,
or exemplary language (e.g. "such as") provided with respect to
certain embodiments herein is intended merely to better illuminate
the invention and does not pose a limitation on the scope of the
invention otherwise claimed. No language in the specification
should be construed as indicating any non-claimed element essential
to the practice of the invention.
[0041] The following discussion provides many example embodiments
of the inventive subject matter. Although each embodiment
represents a single combination of inventive elements, the
inventive subject matter is considered to include all possible
combinations of the disclosed elements. Thus if one embodiment
comprises elements A, B, and C, and a second embodiment comprises
elements B and D, then the inventive subject matter is also
considered to include other remaining combinations of A, B, C, or
D, even if not explicitly disclosed.
[0042] Various terms as used herein are shown below. To the extent
a term used in a claim is not defined below, it should be given the
broadest definition persons in the pertinent art have given that
term as reflected in printed publications and issued patents at the
time of filing.
[0043] The term "heavy oil" as has been used herein throughout the
present disclosure, in the context of its upgradation, denotes the
meaning of hydrocarbon stream(s), preferably having carbons ranging
from C-25 to C-100 and more preferably having carbons ranging from
C-40 to C-60 that may advantageously be subjected to the process of
the instant disclosure.
[0044] The term "untreated naphtha" as has been used herein
throughout the present disclosure, denotes straight run naphtha
such as Light Naphtha (LN) having boiling range of 52.57.degree. C.
to 102.37.degree. C., Heavy Naphtha (HN) having boiling range of
112.97.degree. C. to 136.5.degree. C. and such other grades of
naphtha having carbons ranging C5 to C12, which, preferably, is not
subjected to dearomatization.
[0045] The present disclosure is on the premise of surprising
discovery by inventors of the present invention that execution of
dearomatization process post solvent deasphalting of heavy oil
affords utilization of untreated naphtha as a solvent, which is
significantly economical solvent as compared to treated naphtha and
such other conventional solvents like propane, butane, pentane,
hexane and heptane, wherein the untreated naphtha upon undergoing
dearomatization results in in-situ (or in-line) generation of
treated naphtha (e.g. raffinate) that can be recovered and reused
again in deasphaltenation of heavy oils. Further, the process of
the present disclosure is able to take up incompatible heavy oil
streams as feed in stark contrast to conventional processes,
affording greater flexibility and huge cost savings. Particularly,
the process of the present disclosure affords high flexibility in
the process scheme for using different grades of naphtha for
producing different grades of deasphalted oil with same feedstock
(or feed). It is also suitable to manage feed variations with
varying naphtha quality to produce similar quality of deasphalted
oil in SD-A2 process scheme. Due to flexibility in the process, the
process can be easily integrated with other refinery units wherever
heavy oils are produced and need upgradation for asphaltene and
aromatics removal for value addition.
[0046] Accordingly, an aspect of the present disclosure relates to
a process for solvent deasphalting dearomatization for heavy oil
upgradation, said process including: (a) effecting deasphaltenation
of a heavy oil feed by contacting the feed with a paraffinic rich
solvent in presence of a Fluid Catalytic Cracking (FCC) catalyst to
obtain a deasphalted oil (DAO) rich stream, said paraffinic rich
solvent being untreated naphtha; (b) contacting the deasphalted oil
(DAO) rich stream with a second solvent to obtain a raffinate
stream rich in non-asphaltene and non-aromatic contents and a
solvent rich stream, said second solvent being
N-methyl-2-pyrrolidone (NMP), water and combinations thereof; (c)
contacting the raffinate stream with water in a first decanter to
obtain a first stream rich in aromatic-lean fraction and a second
stream rich in the second solvent and water; (d) subjecting the
first stream to distillation to recover the paraffinic rich solvent
and to obtain deasphalted oil; (e) contacting the solvent rich
stream with water in a second decanter to obtain an aromatic rich
fraction and a third stream rich in the second solvent and water;
and (f) subjecting the second stream and the third stream to
distillation to recover the second solvent and water. In an
embodiment, the recovered paraffinic rich solvent is reused for
effecting deasphaltenation of heavy oil feed. In an embodiment, the
recovered second solvent is reused for effecting dearomatization of
deasphalted oil rich stream. In an embodiment, the weight ratio of
the solvent to the feed (S:F) is between 1:1 to 30:1. However, it
should be appreciated that any other solvent to the feed (S:F)
ratio may be used depending on the heavy oil feed, required
deasphatenation and the likes, without detriment to the scope of
advantageous process of the instant disclosure. In an embodiment,
the Fluid Catalytic Cracking (FCC) catalyst is a spent FCC
catalyst. In an embodiment, the spent FCC catalyst has BET surface
area ranging from 100 m.sup.2/g to 200 m.sup.2/g, micro pore volume
ranging from 0.02 cc/g to 0.08 cc/g, microporous area ranging from
60 m.sup.2/g to 180 m.sup.2/g, and matrix surface area ranging from
40 m.sup.2/g to 80 m.sup.2/g. In an embodiment, the process affords
deasphalting dearomatization of incompatible heavy oil streams. In
an embodiment, the deasphalted oil (DAO) rich stream is contacted
with the second solvent in a weight ratio ranging from 4:1 to 1:4.
In an embodiment, the deasphalted oil (DAO) rich stream is
contacted with the second solvent in a weight ratio ranging from
2:1 to 1:4. In an embodiment, the deasphalted oil (DAO) rich stream
is contacted with the second solvent in a weight ratio of 1:1. In
an embodiment, the step of deasphaltenation of a heavy oil feed is
effected in presence of the Fluid Catalytic Cracking (FCC) catalyst
at an amount ranging from 0.5 wt. % to about 15 wt. %. In an
embodiment, the step of deasphaltenation is effected by contacting
the feed with untreated naphtha in presence of the spent Fluid
Catalytic Cracking (FCC) catalyst to obtain the deasphalted oil
(DAO) rich stream, and wherein the weight ratio of the solvent to
the feed (S:F) is 20:1 and the amount of spent Fluid Catalytic
Cracking (FCC) catalyst is 5 wt. %.
[0047] FIG. 1 illustrates an exemplary schematic showing a process
for solvent deasphalting dearomatization for heavy oil upgradation,
in accordance with an embodiment of the present disclosure. As can
be seen from FIG. 1, heavy oils (FEED) is contacted with paraffinic
rich solvent (SOLV1) to effect deasphaltenation. The weight ratio
of solvent to the feed (S:F) is between 1:1 to 30:1, preferably
between 15:1 to 25:1, and most preferably between 17:1 to 23:1. In
an embodiment, the solvent to the feed (S/F) weight ratio is 20:1.
In an embodiment, heavy oils (FEED) is contacted with paraffinic
rich solvent (SOLV1) to effect deasphaltenation in presence of
Fluid Catalytic Cracking (FCC) catalyst. Fluid Catalytic Cracking
(FCC) catalyst may be a spent (used) catalyst. The spent FCC
catalyst acts as adsorbent material and improves the deasphalting
efficiency. In an embodiment, the spent FCC catalyst is present in
an amount ranging from about 0.5 wt. % to about 15 wt. %,
preferably, in an amount ranging from about 3 wt. % to about 7 wt.
%. In an embodiment, heavy oils (FEED) is contacted with paraffinic
rich solvent (SOLV1) in presence of a spent FCC catalyst to effect
deasphaltenation, wherein weight ratio of solvent to the feed (S:F)
is 20:1, and wherein the spent FCC catalyst is present in an amount
of about 5 wt. %.
[0048] Deasphalting (marked as "EXTRCT-1") separates the pitch
containing a major portion of asphaltene content of the feed and a
portion of solvent (marked as "PITCH"), and a deasphalted oil (DAO)
rich stream (DAO-I) containing a major portion of the
non-asphaltene content of the heavy oil and a portion of solvent
(SOLV1). Solvent (SOVL1) is paraffinic rich and therefore
deasphalted oil (DAO-I) can be directly used as co-processing into
cracking units (FCCU/Hydrocracker), depending upon the quality of
DAO-I and cracking units' tolerance for impurities, even without
recovering the solvent or with partial recovery thereof In an
embodiment, the paraffinic rich solvent is untreated naphtha.
[0049] The deasphalted oil (DAO) rich stream is then contacted with
a second solvent (marked as "SOLV2") to effect dearomatization
(marked as "EXTRCT-2") to obtain a raffinate stream (marked as
"D-RAFF") rich in non-asphaltene and non-aromatic contents, and a
solvent rich stream (marked as "D-EXTRAC"). The deasphalted oil
(DAO) rich stream is contacted with the second solvent in a weight
ratio ranging from 4:1 to 1:4, preferably in a weight ratio ranging
from 2:1 to 1:2. In an embodiment, the deasphalted oil (DAO) rich
stream is contacted with the second solvent in a weight ratio of
about 1:1.The second solvent (SOLV2) may be N-methyl-2-pyrrolinone
(NMP), water, sulfolane, N-formylmorpholine (NFM), tri-ethylene
glycol, tetra-ethylene glycol, furfural and combinations thereof,
but not limited thereto. In an embodiment, the second solvent is
selected from N-methyl-2-pyrrolidone (NMP), water and combinations
thereof.
[0050] The raffinate stream (D-RAFF) is contacted with water (W1)
in a first decanter (DECANT1) to obtain a first stream rich in
aromatic-lean fraction and a second stream rich in the second
solvent and water. The first stream is subjected to distillation
(DIST1) to recover the paraffinic rich solvent (R-SOLV1) and to
obtain deasphalted oil (DAO-II).The solvent rich stream (D-EXTRAC)
is contacted with water (W2) in a second decanter (DECANT2) to
obtain an aromatic rich fraction (A-RICH) and a third stream rich
in the second solvent and water. The second stream and the third
stream are subjected to distillation (DIST2) to recover the second
solvent (R-SOLV2) and water (R-W1, R-W2). As can also be seen from
FIG. 2, the recovered solvents (R-SOLV1, R-SOLV2) and recovered
water (R-W1, R-W2) can be reused for solvent deasphalting
dearomatization for heavy oil upgradation. In an embodiment, the
process for solvent deasphalting dearomatization for heavy oil
upgradation runs in a continuous mode. In an embodiment, the
process for solvent deasphalting dearomatization for heavy oil
upgradation runs in a batch mode.
[0051] It is noteworthy that supplementing the solvent deasphalting
with dearomatization significantly improves the quality and
efficiency. Particularly, the process of the present disclosure
allows utilization of a straight run untreated naphtha as a solvent
in deasphalting, which in the dearomatization process (i.e. the
step of contacting the deasphalted oil rich stream with a second
solvent to obtain the raffinate stream and the solvent rich stream
at EXTRCT-2) undergoes dearomatization along with deasphalted oil
(DAO), resulting in in-situ generation of a paraffin-rich stream
(raffinate), which can be recovered in down-stream processing as
explained hereinabove and can again be used as a solvent for
deasphalting. In this sense, the instant process affords high
flexibility in terms of using different grades of naphtha for
producing different grades of deasphalted oil with same feedstock.
The process is also amenable in managing feed variations with
varying naphtha quality to produce similar quality of deasphalted
oil in the instant process scheme.
[0052] Due to flexibility in the process, the process of the
present disclosure can be easily integrated with other refinery
units (such as FCCU or hydrocracking units) wherever heavy oils are
produced and which need upgradation for asphaltene and aromatics
removal for achieving value addition. The advantageous process of
the instant disclosure is particularly suited for integration with
the fluid catalytic cracking units (FCCU) or hydrocracking units.
The fluid catalytic cracking units (FCCU) or hydrocracking units
may be any conventionally known units, such as downer or riser type
FCC units, operation whereof is well known in the art. In an
exemplary embodiment, the FCC unit is a downer type FCC unit
operating at a temperature ranging from about 550.degree. C. to
650.degree. C. and at a pressure ranging from about 1 to 5 bar
using a zeolite type catalyst (e.g. catalyst having 30-80% zeolite,
10-40% binder, and 5-20% filler, which is a mixture of micro-pore
and meso-pore catalyst). When advantageous process of the instant
disclosure is integrated with the abovementioned downer type FCC
unit, it results in improvement in the gasoline yield to the tune
of 2-5 wt % and in the propylene yield to the tune of 0.5-2 wt %
(with 10% DAO-1 and DAO-2) when compared with utilization of 10%
VR. In another exemplary embodiment, the FCC unit is a riser type
FCC unit operating at a temperature ranging from about 500.degree.
C. to 580.degree. C. and at a pressure ranging from about 1 to 2
bar using a zeolite type catalyst (e.g. catalyst having 30-80%
zeolite, 10-40% binder, and 5-20% filler, which is a mixture of
micro-pore and meso-pore catalyst). When advantageous process of
the instant disclosure is integrated with the abovementioned riser
type FCC unit, it results in improvement in gasoline yield to the
tune of 2-5 wt % and in the propylene yield to the tune of 0.5-2 wt
%, with reduction in the yield of coke to the tune of 1-3 wt %
(with 10% DAO-1 and DAO-2) when compared with utilization of 10%
VR.
[0053] It should be appreciated that usage of Fluid Catalytic
Cracking (FCC) catalyst, albeit optional, can afford improvement in
the efficiency of solvent deasphalting, plausibly owing to
adsorption of asphaltenes on the FCC catalyst, which affords
transfer of adsorbed asphaltenes into pitch fraction resulting in
higher pitch yields and consequently improved quality of
deasphalted oil (DAO). Albeit surprisingly, the inventors of the
present disclosure could note that utilization of spent Fluid
Catalytic Cracking (FCC) catalyst affords marked improvement in the
efficiency of solvent deasphalting. As the spent catalyst is an
undesired material at refinery (which typically is disposed-off)
and available at low cost, usage of the spent FCC catalyst offers
two-fold advantages i.e. meaningful utilization of the spent
catalyst and improvement of the deasphalting efficiency. Spent
Fluid Catalytic Cracking (FCC) catalyst may be used in the solvent
deasphalting in an amount ranging from 0.5 wt. % to about 15 wt. %,
preferably, in an amount ranging from about 3 wt % to about 7 wt %.
In an embodiment, the spent Fluid Catalytic Cracking (FCC) catalyst
is used in the solvent deasphalting in an amount of about 5 wt
%.
[0054] Another aspect of the present disclosure relates to a
process for solvent deasphalting dearomatization for heavy oil
upgradation, said process comprising: (a) effecting
deasphaltenation of a heavy oil feed by contacting the feed with a
paraffinic rich solvent to obtain a deasphalted oil (DAO) rich
stream, said paraffinic rich solvent being untreated naphtha; (b)
contacting the deasphalted oil (DAO) rich stream with a second
solvent to obtain a raffinate stream rich in non-asphaltene and
non-aromatic contents and a solvent rich stream, said second
solvent being N-methyl-2-pyrrolidone (NMP), water or combinations
thereof; (c) contacting the raffinate stream with water in a first
decanter to obtain a first stream rich in aromatic-lean fraction
and a second stream rich in the second solvent and water; (d)
subjecting the first stream to distillation to recover the
paraffinic rich solvent and to obtain deasphalted oil; (e)
contacting the solvent rich stream with water in a second decanter
to obtain an aromatic rich fraction and a third stream rich in the
second solvent and water; and (f) subjecting the second stream and
the third stream to distillation to recover the second solvent and
water. In an embodiment, the recovered paraffinic rich solvent is
reused for effecting deasphaltenation of heavy oil feed. In an
embodiment, the recovered second solvent is reused for effecting
dearomatization of deasphalted oil rich stream. In an embodiment,
the weight ratio of the solvent to the feed (S:F) is between 1:1 to
30:1. In an embodiment, the process affords deasphalting
dearomatization of incompatible heavy oil streams. In an
embodiment, the deasphalted oil (DAO) rich stream is contacted with
the second solvent in a weight ratio ranging from 4:1 to 1:4, said
second solvent being selected from N-methyl-2-pyrrolidone (NMP),
water and combinations thereof.
EXAMPLES
[0055] The crude oil samples were sourced from various part of the
world. Feedstock (vacuum residue (VR) samples: VR1, VR3, VR4, VR5,
VR6, and VR7) was obtained by distillation (ASTM D2892 & D5236)
of crude oils. The end point of vacuum distillation is 565+ deg C.
VR2 feedstock was directly sourced from refinery vacuum tower
bottom (565+). Two standard pure paraffinic solvents and three
different naphtha (treated/untreated) samples from refinery streams
were used in the deasphalting process: n-pentane (C5) (99%,
Sigma-Aldrich) and n-heptane (C7) (99%, Sigma-Aldrich), Light
Naphtha (LN), Heavy naphtha (HN) and Raffinate Naphtha (RN). RN
stream was obtained from aromatics complex unit of Mumbai BPCL
Refinery. Raffinate was produced via liquid-liquid-extraction
(dearomatization) of a mix of naphtha streams in the refinery.
N-Methyl-2-pyrrolidone (NMP) (AR grade, >99%) solvent was
purchased for dearomatization study. FCC Spent Catalyst was brought
from one of the BPCL group refineries, fluid catalytic cracking
unit of Mumbai Refinery.
[0056] Seven different feedstock were characterized and
incompatibility status of the oils were checked using K Model for
their suitability. K Model is the predictive software tool for
prediction the incompatibility/inhomogeneity of oil system based on
physical parameters of the oil (U.S. Pat. No. 10,365,263B1). The
negative K value indicates high incompatibility (inhomogeneity) and
positive K value indicates the compatibility (homogeneity) status
of the oil system. Herein "Asphaltene incompatibility or
inhomogeneity" found to be an important parameters to spot the
favorable deasphalting zone. In the process of present disclosure,
attempt was made to accommodate maximum possible resources from
refinery configuration framework such as solvent, spent catalyst,
in-situ regeneration of deasphalting solvent and its integration
with FCCU so that it becomes an end to end solution for heavy oil
upgradation in its own boundary.
Characterization and Suitability of Feedstock
[0057] Feedstock was characterized for API gravity (ASTM D4052),
Sulphur (ASTM D2622, D4294, D5453), Kinematic Viscosity (ASTM D445,
ASTM D2870 and ASTM D4402), Micro Carbon Residue (ASTM D4530), Pour
Point (ASTM D97, D5853, D5950), Saturate content, Aromatic content,
Resin content and Asphaltene content (IP143), True Boiling Point
(TBP) and PotStill distillation (ASTM D2892 and D5236), Penetration
(ASTM D5), softening (ASTM D36) and Compatibility/Stability (K
Model) of heavy oils. The characterization results of all seven
samples (VR1-VR7) are reported in Table 1.
TABLE-US-00001 TABLE 1 Characterization of heavy oils feedstock
Property Name Unit VR-1 VR-2 VR-3 VR-4 VR-5 VR-6 VR-7 VR Yield wt %
29.33 24.58 23.99 23.94 23.72 21.15 17.52 (crude basis) Density at
gm/cc 1.0398 1.0356 1.0316 1.0303 1.0258 1.0274 1.0211 15.degree.
C. Sp. Gr. at -- 1.0406 1.0366 1.0324 1.0311 1.0266 1.0282 1.0219
60/60.degree. F. API Gravity -- 4.58 5.00 5.66 5.83 6.44 6.23 7.08
Total Sulphur wt % 6.22 5.54 5.27 4.44 7.01 5.72 4.60 Pour Point
.degree. C. 73 60 68 72 59 63 62 Hydrocarbon Types Saturates wt %
6.51 6.14 7.20 8.11 5.77 6.50 7.97 Aromatics wt % 57.77 53.34 54.50
52.04 58.17 55.07 51.66 Resins wt % 17.03 26.53 24.25 26.55 24.42
27.33 30.72 Asphaltenes wt % 18.70 13.99 14.04 13.30 11.64 11.10
9.65 MCR wt % 30.52 25.74 27.64 26.86 25.24 24.87 23.77 KV,
100.degree. C. cSt 27011 5869 5568 19028 4317 6929 5394 Penetration
dm 22.4 39 44.1 33.7 74.0 63.5 91.3 Softening .degree. C. 58.6 52
52.1 54.7 47.2 48.6 45.2 point Compatibility/ -- Incom- Incom-
Inter- Compat- Compat- Compat- Compat- Stability patible patible
mediate ible ible ible ible (K Model) (-0.113) (-0.044) (0.000)
(0.005) (0.0390 (0.054) (0.094) VR: Vacuum Residue; K Model: U.S.
Pat. No. 10,365,263B1
[0058] As can be seen from Table 1, among all seven heavy oils,
Arab Heavy (AH) vacuum residue (VR1) has highest asphaltene content
(18.70 wt %) and all other oils (VR2 to VR6) have asphaltene
content in the range of 9.65 wt % to 14.04 wt %. Sulphur content of
all the VR samples was ranging from 4.44 wt % to 6.22 wt % whereas
API value was ranging from 4.58 to 7.08.
[0059] The incompatibility parameters of all seven samples were
evaluated using K Model and thereafter, subjected to deasphalting.
As per K Model, VR1 & VR2 were incompatible (unstable, high
asphaltene precipitation propensity), VR3 was intermediate (medium
asphaltene precipitation propensity) and VR4 to VR7 were compatible
(stable) feedstock. The ranking of feedstock for its
incompatibility was given as
VR1>VR2>VR3>VR4>VR5>VR6>VR7. The deasphalting
results of all these samples showed highest pitch yields for
incompatible samples (VR1 & VR2), medium pitch yield for
intermediate incompatibility and low pitch yields for compatible
blends as depicted in FIG. 7. High pitch yield of VR1 & VR2
means incompatible feedstock produced high quality deasphalted oils
(DAO). In-fact, the inventors of the present disclosure could note
that feedstock evaluation for incompatibility/un-stability or
inhomogeneity should be done for enhancing the solvent deasphalting
process, wherein the standard compatibility methods including K
Model may be useful for blending the available feedstock for
maximizing the incompatibility to enhance the solvent deasphalting
for heavy oil upgradation. Considering the process development
within refinery configuration framework, feedstock obtained from
refinery (VR2) was selected for deasphalting experiments.
Selection and Characterization of Solvent for Deasphaltenation
[0060] Five different solvents viz. pentane (C5), heptane (C7) and
three different naphtha (untreated/treated) streams from refinery
were studied for deasphaltenation. Naphtha (light naphtha (LN),
heavy naphtha (HN)) is a low value stream in refinery, and if it
meets the deasphalting solvent performance, the overall process
will be cost-effective. Physico-chemical characterization of
naphtha was carried-out before distillation and detailed
hydrocarbon analysis (DHA) was made and correlated with the
desalting performance. A raffinate naphtha (RN) which is a
dearomatized stream obtained from one of the units of refinery
(Aromatics Complex) was used for the study.
[0061] Physico-chemical characterization of deasphalting solvents
was carried-out for distillation using ASTM D86 method and detailed
hydrocarbon analysis (DHA) using ASTM D6729 method was done. DHA
covers the determination of individual hydrocarbon components with
boiling ranges up to 225 .degree. C. These characterizations were
carried-out for refinery solvents (LN, HN, RN)) which are a mixture
of hydrocarbons in the boiling range of 52.57-136.7.degree. C.,
however, the other two solvents (n-C5 & n-C7) were pure alkyl
components. Distillation profile data (ASTM D86) is shown in FIG.
2, and DHA characterization data is reported in Table 2.
TABLE-US-00002 TABLE 2 Hydrocarbon analysis of deasphalting
solvents DHA (%) C5 C7 LN HN RN Saturates (S), wt % Cyclic (S) --
-- 11.38 36.91 12.54 Iso (S) -- -- 17.07 38.48 42.25 Normal (S)
100.00 100.00 6.00 2.54 34.45 Un-saturates (US), wt % Cyclic (US)
-- -- -- -- 0.86 N_Iso (US) -- -- 65.28 15.70 9.90 Aromatics (US)
-- -- 0.27 6.37 0.01 Total 100.00 100.00 100.00 100.00 100.00
n-alkanes (C5 to C7), wt % n-C5 100 -- 0.18 1.11 13.42 n-C6 -- --
0.61 0.12 14.12 n-C7 -- 100 0.29 0.04 0.04
[0062] The distillation range of naphtha streams are viz. Light
Naphtha (boiling range: 52.57-102.37.degree. C.), Heavy naphtha
(boiling range: 112.97-136.5.degree. C.) and Raffinate, (boiling
range: 68.50-93.70.degree. C.). Refinery light naphtha (LN) sample
was observed to be heavier than n-C4 and lighter than n-C8 whereas
heavy naphtha (HN) was heavier among all the solvents. Raffinate
naphtha (RN) is a treated naphtha obtained from aromatics complex
unit of refinery from which aromatics components were extracted
using sulfolane solvent and it has boiling range 68.50-93.70 deg C.
The boiling range of RN lower than n-C9 and higher than n-C4. The
solvent chemical characteristics play a significant role on
deasphalting. Detailed hydrocarbon analysis (DHA) results reported
in Table 2 revealed that RN has highest normal saturates and
iso-saturates with lowest aromatics content. HN has low normal
saturates content among all three naphtha samples chosen.
Hydrocarbon characteristics of all three naphtha samples are
different with respect to boiling range & hydrocarbons
constituents (Table 2) therefore, solvent performances were
expected to be different for deasphalting for yields and
quality.
Solvent Deasphalting Dearomatization & DAO Characterization
[0063] Solvent deasphalting experiments were carried-out using five
different solvents at different solvent to feed (S/F) ratios weight
basis (4, 8, 12, 15 & 20) at ambient conditions for screening
the suitable solvent within refinery framework. With the selected
solvent, fluid catalytic cracking unit spent FCC catalyst (Sp.
Cat.) was added (5 wt %) at different S/F ratio at ambient
condition to study the adsorption of asphaltene molecules for
improving the deasphalting efficiency.
[0064] The experiments began with pre-heating of the VR feedstock
near to its pour point temperature for making it homogeneous to
flow and then it was added into Sp. Cat was mixed with the solvent
and stirred at 500 rpm for 2 hr at 25.degree. C. The settling time
kept for the mixture was about 4 hr. After that the mixture was
decanted on filter cone made up of 2.5 .mu.m Whatman filter paper
so that pitch stay at the surface and DAO was collected in the
flask. The solvent was separated from the DAO by evaporation and
loss was estimated. The DAO and Pitch weight were calculated to
analyze the solvent deasphalting yields with and without spent
catalyst. The DAO obtained from all experiments were characterized
for saturates, aromatics, resins and asphaltenes using IATROSCAN
MK-6 TLC/FID thin layer chromatograph instrument (M/s LSI Medicine
Japan) and sulfur contents using ASTMD1298-12, respectively. The
DAO obtained from the deasphalting experiments is hereinafter be
called DAO-I.
[0065] The feed for dearomatization experiment was DAO-I. In the
present study, DAO-I was obtained from deasphalting using selected
solvent along with Sp. Cat. The most suitable solvent was selected
through modeling & simulation studies of various potential
solvents. Dearomatization experiment was carried out by mixing
DAO-I and selected solvent at 1:1 S/F ratio (weight basis) admixed
with 5wt % water and stirred at 500 rpm at near to the boiling
point temperature of 150-200.degree. C. for 2 hr. The settling time
kept for the mixture for phase separation (upper phase: raffinate,
bottom phase: extract) was about 4 hr. The solvent were separated
from raffinate phase by evaporation and loss was calculated. The
raffinate obtained in dearomatization step is hereinafter called
DAO-II. The DAO-II was further characterized for saturates,
aromatics, resins and asphaltene using IATROSCAN MK-6 TLC/FID thin
layer chromatograph instrument (M/s LSI Medicine Japan).
Spot Test
[0066] This test is based on visual decision and easy to figure out
incompatibility of crude oils and blends. As per ASTM D4740, one
drop of the sample is placed on a filter paper. Then the filter
paper is kept in oven for drying for one hour at 100.degree. C.
After that the observed spot is required to be classified according
to the following types mentioned in Table 3 below. According to
this method, if a spot is classified into category 3 or higher
categories, then the crude oil is marked as incompatible.
TABLE-US-00003 TABLE 3 Spot test characteristics Categories Spot
characteristics 1 Homogeneous spot without inner ring 2 Faint or
poorly defined inner ring 3 Well-defined thin inner ring, only
slightly darker than the background 4 Well-defined inner ring,
thicker than the ring in reference spot No. 3 and somewhat darker
than the background 5 Very dark solid or nearly solid area in the
center. Central area is darker than the background
Characterization of FCC Spent Catalyst
[0067] Spent FCC catalyst (Sp. Cat.) and fresh FCC catalysts were
obtained from fluid catalytic cracking unit (FCCU) of BPCL Mumbai
Refinery and the same was characterized and compared as reported in
Table 4.
TABLE-US-00004 TABLE 4 Characterization of FCC spent catalyst
Properties Spent Catalyst Fresh Catalyst BET SA, m.sup.2/g 196 310
Micro pore volume, cc/g 0.05 -- Micro porous area, m.sup.2/g 132
223 Matrix surface area, m.sup.2/g 64 87 Unit Cell .ANG. 24.25
24.25
Fluid Catalytic Cracking of VGO+DAO for Product Yields
[0068] Cracking experiments were conducted in an ACE-R+ pilot unit
loaded with 4-9 g of spent FCC catalyst. The feed (VGO+DAO
preheated to 40-130.degree. C.) was delivered at 1.125 g/min by a
constant-drive syringe pump and was injected approximately 1 cm
above the catalyst bed at 520.degree. C. The procedure and
characterization of cracked liquid and gaseous products were as
follows: Cycle time for one experiment on the ACE-R+unit is
approximately 2hrs. Each cycle has 15 sub-steps which include
feeding of catalyst, priming and withdrawal of liquid feed using a
calibrated syringe pump, temperature stability check for reaction,
feed injection, catalyst and liquid stripping for removing trapped
hydrocarbons, gas measurement, in-situ regeneration and coke
measurement. Gaseous products from the reaction are collected in a
gas collection vessel and analyzed using an on-line Refinery Gas
Analyzer (RGA). Liquid products are condensed, collected in a vial
and weighed. They are analyzed off-line using a Simulated
Distillation (SimDist) GC. SimDist report presents a summary of the
% weight vs boiling point for the liquid product. Results included
conversion, yields of dry gas (H2-C2), liquefied petroleum gas
(LPG, i.e., C3 and C4), gasoline (IBP-186.degree. C.), light cycle
oil (LCO, 186-343 .degree. C.), heavy cycle oil (HCO,
343-370.degree. C.), (CLO, 370+) and coke. Conversion was
calculated as the summation of dry gas, LPG, gasoline and coke.
Modeling for Selection of Dearomatization Solvent
[0069] The phase equilibria behaviour of six different potential
polar solvents were studied for selection of the most suitable
solvent for dearomatization. These solvents include Sulfolane
(TMS), N-Methyl Pyrolidinone (NMP), Tetra-ethylene-glycol (TETRA),
Tri-ethylene-glycol (TRI), Furfural and N-Formylmorpholine (NFM).
The interaction behaviour of components (C6, C9, C12 & C15):
Paraffin (Hexane, N-Nonane, N-Dodecane & N-Pentadecane),
Aromatics (Benzene, 1-methyl-3-ethylebenzene, 1,2,4-Triethylbenzene
& 1-N-Pentylnaphthalene) and solvents were studied by plotting
ternary phase diagrams at ambient conditions. Ternary phase diagram
for TMS, NMP & TETRA for carbon number C15 components
(paraffin, aromatics) are depicted as an illustration in FIG. 3.
Based on the phase equilibria data analysis, distribution
coefficient, selectivity, and performance index (PI) of the
solvents were investigated. The universal quasi-chemical (UNIQUAC)
model was used to predict the liquid-liquid equilibria (LLE) for
all the hydrocarbon systems in the carbon range (C6 to C15) in
Aspen plus.
[0070] Ternary phase diagrams clearly reveal that the miscible
region, immiscible region, two-phase envelop (equilibrium line),
tie-lines and plait point (wherein, three-component mixture
separates into two phases). The distribution coefficient is defined
as a partition coefficient (C), the ratio of concentrations of a
component in the two phases of a mixture of two immiscible liquids
at equilibrium.
[0071] The distribution coefficient of solvents is defined as
C = Mole .times. .times. fraction .times. .times. of .times.
.times. solute .times. .times. in .times. .times. extract .times.
.times. phase Mole .times. .times. fraction .times. .times. of
.times. .times. solute .times. .times. in .times. .times. raf
.times. finate .times. .times. phase ##EQU00001##
[0072] High distribution coefficient requires low solvent to feed
ratio and this is one of the desirable parameters for solvent
selection. As per ternary phase diagram of TMS reported in FIG. 3,
the miscible region is smallest, the estimated distribution
coefficient is high and it further increases with increasing solute
(aromatics) in extract phase. In the similar manner, distribution
coefficients for all other solvents for carbon range (C6 to C15)
were estimated, analyzed and plotted in FIG. 4.
[0073] The selectivity of solvent is defined as
S = ( Mole .times. .times. fraction .times. .times. of .times.
.times. aromatics .times. .times. in .times. .times. extract
.times. .times. phase ) .times. / ( Mole .times. .times. fraction
.times. .times. of .times. .times. paraffin .times. .times. in
.times. .times. extract .times. .times. phase ) ( Mole .times.
.times. fraction .times. .times. of .times. .times. aromatics
.times. .times. in .times. .times. raffinate .times. .times. phase
) .times. / ( Mole .times. .times. fraction .times. .times. of
.times. .times. paraffin .times. .times. raffinate .times. .times.
phase ) ##EQU00002##
[0074] The selectivity parameters for all the solvents for carbon
range (C6 to C15) were calculated and the same is plotted in FIG.
5. The selectivity of TMS solvent for C15 components (paraffins,
aromatics) interactions was found poor. It is noteworthy to mention
that selectivity is the equilibrium ratio of solute (aromatics) in
each phase and if it is observed to be poor, then the quality of
raffinate produced using low selectivity solvents will always be
inferior.
[0075] High distribution coefficient always gives rise to low
selectivity and vice versa. Therefore, the performance index (PI),
defined as the product of the distribution coefficient and the
selectivity, is regarded as a useful measurement of overall
extraction efficiency. In this section, performance index
parameters were estimated (the same is depicted in FIG. 6) to
investigate the capabilities of solvents for dearomatization for
different carbon numbers C6, C9, C12 & C15 of the feed.
Distribution coefficient of TETRA is found to be better than TMS
for C6 feed (FIG. 4). However, the selectivity and performance
index of Sulfolane is found best among all the solvents for C6
carbon numbers as feed (FIG. 5 and FIG. 6). Therefore, sulfolane
has been widely used in industry as solvent for light naphtha
dearomatization. In case of C9 carbon number, the distribution
coefficients of NMP and TETRA were observed with similar
distribution coefficients (FIG. 4). The selectivity of NFM was
highest among all the solvents for C9. However, the overall
performance index of NMP was found to be superior among all the
solvents even though selectivity of sulfolane and NFM was higher
than NMP (FIG. 5 and FIG. 6). Therefore, it can be noted that mix
of sulfolane and NMP could be best solvent for the hydrocarbon
mixture in the range of C6 to C9. In case of C12, the distribution
coefficient of Furfural is found to be highest (FIG. 4). However,
the selectivity of sulfolane, NMP and NFM was superior to furfural.
In combination of these two parameters, PI for C12 components, NMP
was found to be superior as solvent. In case of C15, although NFM
has highest distribution coefficients but it has poorest
selectivity which turned this solvent as low performer. NMP
performance was found to be highest (FIG. 6) among all the solvents
even though sulfolane has highest distribution coefficient (FIG. 4)
and NFM has highest selectivity (FIG. 5).
[0076] Beyond carbon range C9, NMP was found to be the best solvent
for dearomatization. It is mainly due to balance behaviour for
distribution coefficient and selectivity parameters as compared to
other potential solvents which has either distribution coefficient
is highest but poorest selectivity and vice versa. It is noteworthy
to mention that each solvent performance trends have been different
with respect to increasing carbon number
(C6->C9->C12->C15). FIG. 6 clearly illustrates that
Sulfolane and Furfural have similar PI trend in this carbon number
order as C6>C15>C9>C12; NMP & TETRA have similar trend
in this carbon number order as C15>C6>C9>C12; TRI trend is
C6->C9>C12>C15); and NFM trend is C15>C12>C9>C6
but with poor efficiency. Considering the performance trends and
efficiency, it can be clearly seen that with increasing carbon
number, performance index is highest for NMP. In addition to the
performance, NMP has lowest boiling point among all solvents which
is further encouragement for selection because recovering from
heavy oils (high boiling materials) will be easier due to wider
difference in boiling points. Based on the detailed analysis, NMP
was selected for dearomatization of deasphalted oil.
Effect of Type of Solvents
[0077] FIG. 8 depicts the DAO and pitch yield profiles of different
solvents. FIG. 9 depicts the DAO quality. In deasphalting, yields
and quality are directly related, as lowering DAO yields or
increasing pitch yields clearly means that it is improving the DAO
quality and in a real sense heavy oils are upgraded. High pitch
yields also indicate that large quantity of asphaltenes is
precipitated and therefore, DAO quality has improved. n-C5 showed
highest pitch yield and HN showed lowest pitch yield among all
solvents. Among naphtha solvents, RN showed highest pitch yields
and therefore, the quality of DAO produced by RN solvent was found
to be better as compared to other DAOs obtained with the help of LN
and HN. This % reduction in asphaltene content of feed were 63.16%,
54.28%, 65.78%, 62.23% & 18.86% using n-C5, n-C7, raffinate, LN
and HN solvents, respectively. This clearly revealed that n-C5 is
better solvent than n-C7 and raffinate performance is better as
compared to LN & HN for DAO quality.
[0078] In addition to this, the DAO yields (66.36 wt %, 73.41 wt %,
68.89 wt %, 71.40 wt %, 90.13 wt %) and the sulphur contents (64.26
wt %, 70.22 wt %, 68.23 wt %, 68.77 wt %, 87.73 wt % of the feed
sulphur) in DAO obtained with the help of n-C5, n-C7, RN, LN and HN
solvents respectively as reported in FIG. 9. The DAO yields and %
sulphur content showed linear relationship, it means that
increasing the DAO yields can result in higher amount of sulphur in
the DAO. Along with DAO yields & % reduction in asphaltene, the
sulphur content of DAO also confirms that n-C5 is better as
compared to n-C7, and raffinate was found to be superior among all
naphtha solvents, confirming that utilization of untreated naphtha
(i.e. straight run naphtha such as light naphtha or heavy naphtha),
which upon undergoing dearomatization in the process results in
in-situ (or in-line) generation of treated naphtha (e.g.
raffinate), would serve its intended purpose.
Effect of S/F Ratio on the DAO Yield and Quality
[0079] FIG. 8 shows the DAO and pitch yields for n-C5, n-C7, RN, LN
and HN solvents respectively. Increasing the S/F reduces the DAO
yields and increases the pitch yields however, S/F ratio of 20/1
observed to be optimal at the specified conditions (ambient
temperature & pressure) of SDA experiment. The effect of S/F
ratio on SDA can be explained through change in solvent power,
enhancing resins solubilization which facilitates asphaltene
aggregation and precipitation in turn it increases the pitch yields
and proportionally lower the DAO yields. To further investigate the
effect of S/F ratio on deasphalting, spot test experiments which is
one of the visual methods to figure out the asphaltene
precipitation pattern (indication of incompatibility/inhomogeneity)
were carried out. The interaction of feedstock which is a heavy
material with light solvents have been observed and correlated with
incompatibility of blending. The pattern of addition of light
hydrocarbons with 10% increase in each step into heavy oil, it
maintains the compatibility of the blend which is an unfavorable
condition for SDA. Conversely, the pattern of addition of heavy oil
in light oil with increase of 10% in each step immediately creates
incompatibility in the system which is higher S/F ratio case
wherein in solvent (light oil) is the continuous phase. The pattern
of step-wise blending of light into heavy (low S/F) and heavy into
light (high S/F) with incompatibility/compatibility region is the
clear demonstration of favorable deasphalting as depicted in FIG.
10. In fact, it is showing that higher S/F ratio increases the
extent of incompatibility in the system, disturbs the homogeneity
of the oil system for deasphalting. Due to high incompatibility at
higher S/F ratio, asphaltene precipitates out in large quantity and
thus, increases the pitch yields and proportionally decreases the
DAO yields which results in improving DAO quality.
Impact of Spent Catalyst in the Deasphalting Process
[0080] Using FCCU spent catalyst material, deasphalting experiments
were carried out with raffinate solvent at different S/F ratio (4,
8, 12, 16, 20) and yield profile & quality of DAO observed.
FIG. 8 depicted the yield of (a) DAO and (b) pitch as a function of
S/F ratio at fixed 5 wt % dosage of spent catalyst. Due to addition
of spent catalyst, there is lowering of DAO yield by 2 wt % and
pitch yield was proportionally increased after adsorbing asphaltene
molecules on the catalyst surface. It is noteworthy to mention that
spent catalyst is the zeolite material with Bronsted acid sites and
therefore, its selectivity toward asphaltenes on the catalyst
surface and its interaction with the asphaltenes and subsequent
adsorption was anticipated. However, with increasing S/F ratio, the
improvement in pitch yield and lowering in the DAO yield trend was
observed to be consistent as shown in FIG. 8. By observing the DAO
& pitch yield profile, it is confirmed that the solvent needed
for deasphalting can be significantly reduced with the help of
spent catalyst adsorbent to obtain similar DAO yields and quality
at higher S/F ratio.
[0081] To witness the quality improvement in DAO, 7.32 wt %
reduction in asphaltene content (initial asphaltene content from
4.79 wt % to 3.76 wt % in DAO) was observed as reported in FIG.
9(a). This improvement in quality is attributed mainly to the
interaction between the asphaltenes and the spent catalyst that
remain in the pitch fraction. However, small change (from 3.78 wt %
to 3.70 wt %) in sulphur content was observed as reported in FIG.
9(b). It was interesting to note the relationship between
asphaltene and sulphur constituents association in the heavy oil
system. The change in sulfur content was insignificant, this could
be due to the fact that --N-- and --O-- containing asphaltene
groups were lead to get adsorbed on the spent catalyst surface over
that of sulphur group asphaltenes.
Dearomatization of Deasphalted Oil
[0082] The purpose of supplementing the process with
dearomatization is to feed high quality diet to cracking units.
Otherwise it has to compromise with low value options such as
blending with lower quantity, bitumen feedstock or fuel oil
blending stock etc. To explore the possibilities, dearomatization
experiment using NMP was carried out at temperature near the
boiling point of solvent i.e., T=200.degree. C.; S/F ratio=1/1
(w/w); and stirring time t=4 hours and raffinate and extract were
separated. The raffinate (dearomatized product) in this case was
DAO-II. The dearomatization product DAO-II yield was 77.33 wt %.
Due to NMP extraction, the quality of DAO-II was improved for
asphaltene content (reduced from 3.76 wt % to 0.8 wt %), aromatics
content (reduced from 56.30 wt % to 40.94 wt %) and saturate
content (increased from 9.00 wt % to 29.96 wt %). However, there
was less impact on resin content (it was marginally changed from
30.94 wt % to 28.31 wt %). The comparison of quality of DAO-I and
DAO-II has been depicted in FIG. 12. This means that aromatics
components have been selectively removed by NMP and due to this the
final product became paraffin-rich and therefore solvent
deasphalting dearomatized product DAO-II found to be appropriate
for catalytic cracking. It was observed that NMP extraction has
improved the DAO-I quality into most suitable feedstock for
cracking in secondary refinery units.
Fluid Catalytic Cracking of Deasphalted Dearomatized Oil
[0083] Fluid catalytic cracking was carried out with five different
feedstock viz. (a) conventional vacuum gas oil (VGO), (b) VGO mixed
with neat VR2 (10 wt %) which is a feedstock to SD-A.sup.2, (c) VGO
mixed with DAO-I (10 wt %) and (d) VGO mixed with DAO-II (10 wt %)
respectively at the conditions mentioned hereinabove. To understand
the impact at each stage of the process, the FCC product yields
were compared and reported in Table 5.
TABLE-US-00005 TABLE 5 Fluid Catalytic Cracking of DAOs Catalyst
FCCU spent catalyst Catalyst BET SA (196 m2/g); Micro pore volume
(0.05 cc/g); characteristics Micro porous area (132 m2/g); Matrix
surface area (64 m2/g); Unit Cell (24.25 .ANG.) FCCU pilot plant
Temperature = 520.degree. C., Injection time = 27 seconds;
conditions Cat/Oil ratio = 4/1 Feed Name VGO + VGO + VGO + VR2
DAO-I DAO-II VGO (10 wt %) (10 wt %) (10 wt %) Conversion, wt %
65.13 67.68 71.12 71.00 Coke, wt % 4.44 7.31 6.79 4.18 Dry Gas 1.38
1.52 1.77 1.22 LPG 15.37 14.82 16.28 16.15 C3s 5.69 5.56 5.74 5.80
C4s 9.69 9.27 10.54 10.35 Gasoline, wt % 43.93 44.03 46.28 49.45
LCO, wt % 25.41 20.09 18.60 20.60 HCO, wt % 3.09 2.67 2.52 2.11
Bottoms (370+), 6.38 9.56 7.77 6.29 wt %
[0084] Gasoline is a high value and high demand product and
therefore it is always targeted to produce in largest quantity.
Table 5 data clearly showed that gasoline yield has direct
relationship with DAO quality, it increases with improving the DAO
quality. In the experimental results, gasoline yields increased by
0.10 wt %, 2.35 wt % & 5.52 wt % by addition of 10 wt % each
VR, DAO-I & DAO-II respectively. In is noteworthy to mention
that there is increase on 3.17 wt % more gasoline yields on account
of supplemented dearomatization step which is significant. This is
primarily due to improving the paraffinic composition (high
saturates) of DAO-II which is the prime precursor for producing
high octane gasoline blend and that could be achieved through
combining deasphalting followed by dearomatization. There is no
significant change in gasoline yields due to 10 wt % addition of
VR, it implies that up to 10 wt % of VR blending, there is no
change in paraffinic composition of feedstock. Coke yield has
always been the concern for FCCU, and especially when any other
heavy material is mixed with conventional VGO feedstock for value
maximization. Excess coke yield can imbalance the heat of combined
operation of cracker which is endothermic process, and the
regenerator which is an exothermic process. It also affects the
catalyst activity and product selectivity (by blocking the active
sites) and therefore, undesired product yields such as bottom and
dry gas will be higher. Neat heavy oils (e.g., VR) contains high
Asphaltene and high CCR content which particularly indicates high
aromatics compounds in the feed and both the properties are coke
precursors. Therefore combining deasphalting and dearomatization
can improve both the aspects and produce suitable feedstock for
cracking.
[0085] The coke yield has drastically increased by 2.87 wt % when
10 wt % neat VR was mixed with VGO; when 10 wt % DAO-I (deasphalted
oil) mixed with VGO, still there is2.35 wt % increase in coke
yield. Mixing of 10 wt % deasphalted dearomatized oil (DAO-II) with
VGO resulted in decrease of 0.26 wt % coke yield which is an
encouragement to invite such diet to keep catalyst, process,
equipment & environment along with economics in a healthy
conditions. The coke yields trends also reflected on dry gas
yields. It is higher for VGO+10% VR & VGO+DAO-I, however it is
lower for VGO+DAO-II. Dry gas yields also contains H2S which is
generally due to sulphur compounds embedded in large structure of
asphaltene and it come out during thermal cracking. Therefore,
lower asphaltenic feed VGO+DAO-II produced 0.30 wt % lower dry gas
than VGO+VR2. LPG (C3+C4) is also a high value product generally
used as either domestic cooking or for production of oxygenates as
octane improvers. The impact of solvent deasphalting (VGO+DAO-I) on
LPG yield is noted to be about 0.91 wt % as compared to neat VGO,
however, further dearomatization of feedstock (VGO+DAO-II) has
insignificant impact (-0.13 wt %) on LPG yield at the specified
FCCU operating conditions. It is also important to note that
without SD-A.sup.2 (i.e., with VGO+VR feed), there is decrease in
LPG yields by 0.55 wt %. Therefore, treatment of feedstock is
necessary for increasing the valuable product yields. The
undesirable products such as LCO & HCO have proportionally
decreased with solvent deasphalting dearomatization of
feedstock.
[0086] While the foregoing description discloses various
embodiments of the disclosure, other and further embodiments of the
invention may be devised without departing from the basic scope of
the disclosure. The invention is not limited to the described
embodiments, versions or examples, which are included to enable a
person having ordinary skill in the art to make and use the
invention when combined with information and knowledge available to
the person having ordinary skill in the art.
ADVANTAGES
[0087] The present disclosure provides an improved process for
heavy oil upgradation that is not dependent on utilization of
conventional costly solvents such as propane, butane, pentane,
hexane, heptane and treated naphtha.
[0088] The present disclosure provides an improved process for
heavy oil upgradation that is significantly economical and which
can take up incompatible heavy oil streams as feed.
* * * * *