U.S. patent application number 15/120931 was filed with the patent office on 2016-12-15 for process for upgrading refinery heavy hydrocarbons to petrochemicals.
This patent application is currently assigned to SAUDI BASIC INDUSTRIES CORPORATION. The applicant listed for this patent is SABIC GLOBAL TECHNOLOGIES B.V., SAUDI BASIC INDUSTRIES CORPORATION. Invention is credited to Arno Johannes Maria OPRINS, Raul VELASCO PELAEZ.
Application Number | 20160362618 15/120931 |
Document ID | / |
Family ID | 50156658 |
Filed Date | 2016-12-15 |
United States Patent
Application |
20160362618 |
Kind Code |
A1 |
OPRINS; Arno Johannes Maria ;
et al. |
December 15, 2016 |
PROCESS FOR UPGRADING REFINERY HEAVY HYDROCARBONS TO
PETROCHEMICALS
Abstract
The present invention relates to a process for upgrading
refinery heavy hydrocarbons to petrochemicals, comprising the
following steps of: (a) feeding a hydrocarbon feedstock to a ring
opening reaction area; (b) feeding the effluent from (a) to a
separation unit for producing gaseous stream comprising light
boiling hydrocarbons, a liquid stream comprising naphtha boiling
range hydrocarbons and a liquid stream comprising diesel boiling
range hydrocarbons; (c) feeding said liquid stream comprising
naphtha boiling range hydrocarbons to a hydrocracking unit.
Inventors: |
OPRINS; Arno Johannes Maria;
(Geleen, NL) ; VELASCO PELAEZ; Raul; (Geleen,
NL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SAUDI BASIC INDUSTRIES CORPORATION
SABIC GLOBAL TECHNOLOGIES B.V. |
Riyadh
Bergen OP Zoom |
|
SA
NL |
|
|
Assignee: |
SAUDI BASIC INDUSTRIES
CORPORATION
Riyadh
SA
SABIC GLOBAL TECHNOLOGIES B.V.
Bergen OP Zoom
SA
|
Family ID: |
50156658 |
Appl. No.: |
15/120931 |
Filed: |
December 23, 2014 |
PCT Filed: |
December 23, 2014 |
PCT NO: |
PCT/EP2014/079193 |
371 Date: |
August 23, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10G 69/123 20130101;
C10G 2400/04 20130101; C10G 69/06 20130101; C10G 2300/1051
20130101; C10G 2400/30 20130101; C10G 2400/20 20130101; C10G
67/0445 20130101; C10G 2400/28 20130101; C10G 69/00 20130101 |
International
Class: |
C10G 69/12 20060101
C10G069/12; C10G 69/06 20060101 C10G069/06; C10G 69/00 20060101
C10G069/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 25, 2014 |
EP |
14156629.9 |
Claims
1. A process for upgrading refinery heavy hydrocarbons to
petrochemicals, comprising the following steps of: (a) feeding a
hydrocarbon feedstock to a ring opening reaction area; (b) feeding
effluent from step (a) to a separation unit for producing a gaseous
stream comprising light boiling hydrocarbons, a liquid stream
comprising naphtha boiling range hydrocarbons and a liquid stream
comprising diesel boiling range hydrocarbons; (c) feeding said
liquid stream comprising naphtha boiling range hydrocarbons to a
hydrocracking unit, (d) separating reaction products of said
hydrocracking unit of step (c) into an overhead gas stream,
comprising light boiling hydrocarbons, and a mixture of benzene,
toluene and xylenes (BTX)comprising a bottom stream, (e) feeding
the overhead gas stream from the hydrocracking unit of step (d) and
the gaseous stream from the separation unit of step (b) to a steam
cracking unit and at least one or more units chosen from a propane
dehydrogenation unit, a butane dehydrogenation unit, or combined
propane-butane dehydrogenation unit, after separating a hydrogen
containing stream from said gas streams.
2. The process as set forth in claim 1, further comprising feeding
the overhead gas stream from the hydrocracking unit of step (d) and
the gaseous stream from the separation unit of step (b) to another
separation unit and feeding the thus separated streams to said
steam cracking unit and at least one of the propane dehydrogenation
unit, the butane dehydrogenation unit, or the combined
propane-butane dehydrogenation unit.
3. The process as set forth in claim 1, wherein said
dehydrogenation process is a catalytic process and said steam
cracking process is a thermal cracking process.
4. The process according to claim 1, further comprising pretreating
said hydrocarbon feedstock in an aromatics extraction unit, from
which aromatics extraction unit its aromatics rich stream is fed
into said reaction area for ring opening, wherein said aromatics
extraction unit is chosen from a distillation unit, a molecular
sieve extraction unit, and a solvent extraction unit, and further
comprising pretreating said hydrocarbon feedstock in a splitter
unit, from which splitter unit the naphtha boiling range
hydrocarbons fraction is fed directly into said hydrocracking unit
and its heavier fraction is fed into said ring opening reaction
area, and further comprising pretreating said hydrocarbon feedstock
in a pre-hydrocracking unit, from which pre-hydrocracking unit a
heavy hydrocarbons fraction is fed to said ring opening reaction
area, a stream comprising naphtha boiling range hydrocarbons is fed
directly to said hydrocracking unit and a gaseous stream comprising
liquefied petroleum gas (LPG) is fed to a steam cracking unit and
one or more units chosen from the group of propane dehydrogenation
unit, butane dehydrogenation unit and combined propane-butane
dehydrogenation unit, and further comprising pretreating said
hydrocarbon feedstock in a hydrodealkylation/reforming type unit,
from which hydrodealkylation/reforming type unit a BTXE type stream
is obtained, a heavy hydrocarbons fraction is fed to said ring
opening reaction area and a gaseous stream comprising LPG is fed to
a steam cracking unit and one or more units chosen from the group
of, propane dehydrogenation unit, butane dehydrogenation unit and
combined propane-butane dehydrogenation unit.
5. The process according to claim 4, further comprising feeding at
least one of said gaseous stream from said separation unit of step
(b), said gaseous stream from said hydrodealkylation/reforming type
unit and said gaseous stream from said pre-hydrocracking unit to
said hydrocracking unit.
6. The process according to claim 1, further comprising feeding
said bottom stream from said hydrocracking unit to a
transalkylation unit.
7. The process according to claim 1, further comprising feeding
said liquid stream comprising diesel boiling range hydrocarbons
from said separation unit to an aromatics saturation unit.
8. The process according to claim 5, further comprising separating
the overhead gas stream from said hydrocracking unit, the gaseous
stream from said separation unit of step (b), and optionally the
gaseous streams from said pre-hydrocracking unit and said
hydrodealkylation/reforming type unit, into individual streams,
each stream predominantly comprising C2 paraffins, C3 paraffins and
C4 paraffins, respectively, and feeding each individual stream to a
specific furnace section of said steam cracker unit, wherein a
hydrogen containing stream is sent to one or more hydrogen
consuming process units, such as said (pre)-hydrocracking unit and
said reaction area for ring opening, and feeding only the C3-C4
fraction to at least one of said dehydrogenation units as separate
C3 and C4 streams or as combined C3+C4 streams.
9. The process as set forth in claim 1, wherein the process
conditions prevailing in said reaction area for ring opening are a
temperature from 100.degree. C. to 500.degree. C. and a pressure
from 2 to 10 MPa together with from 50 to 300 kg of hydrogen per
1,000 kg of feedstock over an aromatic hydrogenation catalyst and
passing the resulting stream to a ring cleavage unit at a
temperature from 200.degree. C. to 600.degree. C. and a pressure
from 1 to 12 MPa together with from 50 to 200 kg of hydrogen per
1,000 kg of said resulting stream over a ring cleavage
catalyst.
10. The process as set forth in claim 1, wherein the process
conditions prevailing in said separation unit are a temperature
from 149.degree. C. to 288.degree. C. and a pressure from 1 MPa to
17.3 Mpa.
11. The process as set forth in claim 1, wherein the process
conditions prevailing in said hydrocracking unit are a reaction
temperature of 300-580 .degree. C., a pressure of 0.3-5 MPa gauge,
guage, and a Weight Hourly Space Velocity (WHSV) of 0.1-10 h-1.
12. The process as set forth in claim 1, wherein the process
conditions prevailing in said steam cracking unit are a reaction
temperature ranging from 750.degree. C. to 900.degree. C.,
residence times of 50-1000 milliseconds and a pressure ranging from
atmospheric pressure up to 175 kPa gauge.
13. The process as set forth in claim 1, wherein the hydrocarbon
feedstock of step (a) is chosen from shale oil, crude oil,
kerosene, diesel, atmospheric gas oil (AGO), gas condensates,
waxes, crude contaminated naphtha, vacuum gas oil (VGO), vacuum
residue, atmospheric residue, naphtha and pretreated naphtha, light
cycle oil/heavy cycle oil (LCO/HCO), coker naphtha and diesel, FCC
naphtha and diesel, and slurry oil, or a combination thereof.
14. (canceled)
15. (canceled)
Description
[0001] The present invention relates to a process for upgrading
refinery heavy hydrocarbons to petrochemicals.
[0002] EP 1 779 929 relates to a process for the conversion of
sulphur containing hydrocarbon feedstocks into a form suitable for
use in automotive diesel.
[0003] US patent application No 2012/000819 relates to a method for
producing an alkyl benzene with a high added value, and a catalyst
used therefor, wherein the method allows a minimum naphthene
ring-opening reaction to occur by causing an appropriate
hydrocracking reaction without causing unnecessary nuclear
hydrogenation.
[0004] U.S. Pat. No. 4,943,366 relates to the production of high
octane gasoline by hydrocracking highly aromatic fractions obtained
from catalytic cracking operations, wherein a gas oil or resid feed
is cracked in an FCC unit and the cracking products are
fractionated in the cracker fractionator and in a distillation
tower. The lower boiling fraction is then passed to hydrotreater
which forms the first stage of the hydrocracking unit. The
hydrotreated cycle oil then passes to another hydrocracker which
forms the second stage of the unit in which, the saturation of the
aromatics continues and ring opening and cracking take place to
form a hydrocracked product. After hydrogen separation in a
separator, the hydrocracker effluent is fractionated in a
distillation tower to form the products including dry gas,
gasoline, middle distillate and a bottoms fraction.
[0005] WO2007/055488 relate , to a method of preparing aromatic
hydrocarbons and liquefied petroleum gas (LPG) from hydrocarbon
mixture, comprising the following steps of: (a) introducing a
hydrocarbon feedstock mixture and hydrogen into at least one
reaction zone; (b) converting the hydrocarbon feedstock mixture in
the presence of a catalyst to (i) a non-aromatic hydrocarbon
compound through hydrocracking and to (ii) an aromatic hydrocarbon
compound which is abundant in benzene, toluene and xylene (BTX)
through dealkylation/transalkylation within the reaction zone; and
(c) recovering the LPG and aromatic hydrocarbon compound,
respectively from the reaction products step (b) through gas-liquid
separation and distillation.
[0006] WO99/22577 relates to a low pressure hydrocracking, the
process comprising the following steps; (a) mixing a liquid feed
with hydrogen gas, (b) hydrocracking said mixture in a fixed bed
hydrocracker which possesses at least two beds of packed catalyst
particles, producing a lighter fraction and a heavier fraction, c)
passing a portion of the heavier fraction through an extinction
recycle process comprising the following steps: (1) passing the
material to be recycled to a hydrocracker and (2) recycling the
heavier fraction of the effluent.
[0007] US patent application No 2012/205285 relates to a process
for hydroprocessing a hydrocarbon feed, which comprises (a)
contacting the feed with (i) a diluent and (ii) hydrogen, to
produce a liquid feed; (b) contacting the liquid feed with a first
catalyst in a first treatment zone, to produce a first product
effluent; (c) contacting the first product effluent with a second
catalyst in a second treatment zone, to produce a second product
effluent; and (d) recycling a portion of the second product
effluent as a recycle product stream for use in the diluent in step
(wherein the first treatment zone comprises at least two stages,
wherein the first catalysts is hydrotreating catalyst and the
second catalyst is a ring opening catalyst, the first and second
treatment zones are liquid-full reaction zones.
[0008] US patent application No 2012/083639 relates to process for
maximizing high-value aromatics production utilizing stabilized
crude benzene withdrawal, the process comprising the steps of
separating aromatic reactor effluent comprising a C5-fraction and a
C6 to C10 fraction into a benzene-rich stream and at least one
liquid stream and at least one vapor stream depleted in benzene,
one of the liquid streams depleted on benzene comprising a
benzene-depleted C6-fraction and removing at least a portion of the
C5 -fraction from the benzene-rich stream.
[0009] US patent application No. 2006/287561 relates to a process
for increasing the production of C2-C4 light olefin hydrocarbons by
integrating a process for producing an aromatic hydrocarbon mixture
and liquefied petroleum gas (LPG) from a hydrocarbon mixture and a
process for producing a hydrocarbon feedstock which is capable of
being used as a feedstock in the former process.
[0010] US patent application No 2007/062848 relates to a process
for hydrocracking a feed comprising not less than 20 weight % of
one or more aromatic compounds containing at least two fused
aromatic rings which compounds are unsubstituted or substituted by
up to two C1-4 alkyl radicals to produce a product stream
comprising rot less than 35 weight % of a mixture of C2-4 alkanes.
According to US patent application No 2007/062848 bitumen from the
oil sands is fed to a conventional distillation unit, an a naphtha
stream from the distillation unit is fed to a naphtha hydrotreater
unit. The overhead gas stream is a light gas/light paraffin stream
arid fed to hydrocarbon cracker. A diesel stream the distillation
unit is fed to a diesel hydrotreater unit, and the gas oil stream
from the distillation unit is fed to a vacuum distillation unit,
wherein a vacuum gas oil stream from the vacuum distillation unit
is fed to a gas oil hydrotreater. A light gas stream from the gas
oil hydrotreater is fed to hydrocarbon cracker. The hydrotreated
vacuum gas oil from the vacuum gas oil hydrotreater is fed to a
catalytic cracker unit. The bottom stream from the vacuum
distillation unit is a vacuum (heavy) residue and is sent to a
delayed coker producing a number of streams, such as a naphtha
stream being sent to a naphtha hydrotreater unit, a diesel stream
is sent to diesel hydrotreater unit to produce hydrotreated diesel,
and a gas oil stream is fed to a vacuum gas oil hydrotreater unit
resulting in a hydrotreated gas oil stream which is fed to a
catalytic cracker unit.
[0011] U.S. Pat. No. 4,137,147 relates to a process manufacturing
ethylene and propylene from a charge having a distillation point
lower than about 360 DEG C. and containing at least normal and
iso-paraffins having at least 4 carbon atoms per molecule, wherein:
said charge is subjected to a hydrogenolysis reaction it a
hydrogenolysis zone, in the presence of a catalyst, (b) the
effluents from the hydrogenolysis reaction are fed to a separation
zone from which are discharged (i) from the top, methane and
possibly hydrogen, (ii) a fraction consisting essentially of
hydrocarbons with 2 and 3 carbon atoms per molecule and (iii) from
the bottom, a fraction consisting essentially of hydrocarbons with
at least 4 carbon atoms per molecule, (c) only said action
consisting essentially of hydrocarbons with 2 and 3 carbon atoms
per molecule is fed to a steam-cracking zone, in the presence of
steam, to transform at least a portion of the hydrocarbons with 2
and 3 carbon atoms per molecule to monoolefinic hydrocarbons; said
fraction consisting essentially of hydrocarbons with at least 4
carbon atoms per molecule, obtained from the bottom of said
separation zone, is supplied to a second hydrogenolysis zone where
it is treated in the presence of a catalyst, the effluent from the
second hydrogenolysis zone is supplied to a separation zone to
discharge, on the one hand, hydrocarbons with at least 4 carbon
atoms per molecule which, are recycled at least partly to the said
second hydrogenolysis zone, and, on the other hand, a fraction
consisting essentially of a mixture of hydrogen, methane and
saturated hydrocarbons with 2 and 3 carbon atoms per molecule: a
hydrogen stream and a methane stream are separated from said
mixture and there is fed to said steam-cracking zone the
hydrocarbons of said mixture with 2 and 3 carbon atoms, together
with said fraction consisting essentially of hydrocarbons with 2
and 3 carbon atoms per molecule as recovered from said separation
zone following the first hydrogenolysis zone. At the octet of the
steam-cracking zone are thus obtained, in addition to a stream of
methane and hydrogen and a stream of paraffinic hydrocarbons with 2
and 3 carbon atoms per molecule, olefins with 2 and 3 carbon atoms
per molecule and products with at least 4 carbon atoms per
molecule.
[0012] EP 0 219 195 relates to process for the conversion of a feed
comprised of hydrocarbon compounds to lower boiling, higher octane
hydrocarbons by contacting said feed, in the presence of hydrogen,
over a catalyst to selectively hydrogenate and hydrocrack fused
two-ring hydroaromatic hydrocarbon compound to produce a lower
molecular weight, higher octane product.
[0013] WO2012/071137 relates to a process for preparing a gas
cracker feedstock, comprising contacting a feed containing one or
more paraffins comprising 4 to 12 carbon atoms with a catalyst in
the presence of hydrogen at elevated temperatures and elevated
pressures and converting at least 40 wt % of the paraffin
comprising 4 to 12 carbon atoms based on the total weight of
paraffins comprising 4 to 12 carbon atoms in the feed to ethane
and/or propane to obtain a hydrocracked gas cracker feedstock
comprising ethane and/or propane.
[0014] U.S. Pat. No. 6,187,984 relates to a method for the
dehydrogenation of n-butane to butenes comprising contacting a
feedstock containing n-butane under reaction conditions suitable
for the conversion of n-butane to butenes in the presence of a
catalyst.
[0015] US patent application No. 2003/232720 relates to a method of
dehydrogenating a dehydrogenatable hydrocarbon comprising
contacting the dehydrogenatable hydrocarbon with a dehydrogenation
catalyst composite to provide a dehydrogenated hydrocarbon.
[0016] Conventionally, crude oil is processed, via distillation,
into a number of cuts such naphtha, gas oils and residua. Each of
those cuts has a number of potential uses such as for producing
transportation fuels such as gasoline, diesel and kerosene or as
feeds to some petrochemicals and other processing units.
[0017] Light crude oil cuts such as naphthas and some gas oils can
be for producing light olefins and single ring aromatic compounds
via processes such as steam cracking in which the hydrocarbon feed
stream is evaporated and diluted with steam and then exposed to a
very high temperature (750.degree. C. to 900.degree. C.) in short
residence time (<1 second) furnace (reactor) tubes. In such a
process the hydrocarbon molecules in the feed are transformed into
(on average) shorter molecules and molecules with lower hydrogen
carbon ratios (such as olefins) when compared to the feed
molecules. This process also generates hydrogen as a useful
by-product and significant quantities of tower value co-products
such, as methane and C9+ Aromatics and condensed aromatic species
(containing more aromatic rings which share edges).
[0018] Typically, the heavier (or higher boiling point) aromatic
species, such as residua are further processed in a crude oil
refinery to maximize the yields of lighter (distillable) products
from the crude oil. This processing can be carried out processes
such as hydro-cracking (whereby the hydro-cracker feed exposed to a
suitable catalyst under conditions which result in some fraction of
the feed molecules being broken into shorter hydrocarbon molecules
with the simultaneous addition of hydrogen). Heavy refinery stream
hydrocracking is typically carried out high pressures and,
temperatures and thus has a high capital cost.
[0019] Heavier crude oil cuts are relatively rich in substituted
aromatic species and especially substituted condensed aromatic
species (containing two or more aromatic rings which share edges)
and under steam cracking conditions these materials yield
substantial quantities of heavy by products such as C9+ aromatics
and condensed aromatics. Hence, a consequence of the conventional
combination of crude is distillation and steam cracking is that a
substantial fraction of the crude oil is preferably not processed
via the steam cracker as the cracking yield of valuable products
from heavier cuts is not considered to be sufficiently compared to
the alternative refinery fuel value.
[0020] Another aspect of the technology discussed above is that
even when only light crude oil cuts (such as naphtha) are processed
via steam cracking a significant fraction of the feed stream is
converted into low value heavy by-products such as C9+ aromatics
and condensed aromatics. With typical naphthas and gas oils these
heavy by-products might constitute 2 to 25% of the total product
yield (Table VI, Page 295, Pyrolysis: Theory and industrial
Practice by Lyle F. Albright et al, Academic 1983). Whilst this
represents a significant financial downgrade of expensive naphtha
and/or gas oil in lower value material on the scale of a
conventional steam cracker the yield of these heavy by-products
does justify the capital investment required to up-grade these
materials (e.g. by hydrocracking) into streams that might produce
significant quantities of higher value chemicals. This is partly
because hydrocracking plants have high capital costs and as with
most petrochemicals processes, the capital cost of these units
typically scales with throughput raised to the power of 0.6 or 0.7.
Consequently, the capital costs of a small scale hydro-cracking
unit are normally considered to be too high to justify such an
investment to process steam cracker heavy by-products.
[0021] Another aspect of the conventional hydrocracking of heavy
refinery streams such as residua is that these are typically
carried out under compromise conditions chosen to achieve the
desired overall conversion. As the feed streams contain a mixture
of species with a range of ease of cracking this result in some
fraction of the distillable products formed by hydrocracking of
relatively easily hydrocracked species being further converted
under the conditions necessary to hydrocrack species more difficult
to hydrocrack. This increases the hydrogen consumption and heat
management difficulties associated with the process and also
increase the yield of light molecules such as methane at the
expense of more valuable species.
[0022] A result of such a combination of crude oil distillation and
steam cracking of the lighter distillation cuts is that steam
cracking furnaces are typically unsuitable for the processing of
cuts which contain significant quantities of material with a
boiling point greater than .about.350.degree. C. as it is difficult
to ensure complete evaporation of these cuts prior to exposing the
mixed hydrocarbon and steam stream the high temperatures required
to promote thermal cracking. If droplets of liquid hydrocarbon are
present in the hot sections of cracking tubes coke is rapidly
deposited on the surface which reduces heat transfer and increases
pressure drop and ultimately curtails the operation of the cracking
tube necessitating a shut-down of the furnace to allow for
decoking. Due to this difficulty a significant portion of the
original crude oil cannot be processed into light olefins and
aromatic species via a steam cracker.
[0023] US2009/173665 relates to a catalyst and process for
increasing the monoaromatics content of hydrocarbon feedstocks that
include polynuclear aromatics, wherein the increase in
monoaromatics can be achieved with an increase gasoline/diesel
yields and while reducing unwanted compounds thereby providing a
route for upgrading hydrocarbons that include significant
quantities of polynuclear aromatics.
[0024] The LCO Unicracking LCO-X process of UOP as disclosed in
WO2009/008878 uses partial conversion hydrocracking to produce high
quality gasoline and diesel stocks in a simple once-through flow
scheme. The feedstock is processed over a pre-treatment catalyst
and then hydrocracked in the same stage. The products are
subsequently separated without the need for liquid recycle. The LCO
Unicracking process can be designed for lower pressure operation
meaning that the pressure requirement will be somewhat higher than
high severity hydrotreating but significantly lower than a
conventional partial conversion and full conversion hydrocracking
unit design. The upgraded middle distillate product makes a
suitable ultra-low sulphur diesel (ULSD) blending component. The
naphtha product from low-pressure hydrocracking of LCO-X has ultra
low sulphur and high octane and can be directly blended into the
ultra-low sulphur gasoline (ULSG) pool.
[0025] U.S. Pat. No. 7,513,988 relates to a process to treat
compounds comprising two or more fused aromatic rings to saturate
at least one ring and then cleave the resulting saturated ring from
the aromatic portion of the compound to produce a C2-C4 alkane
stream and an aromatic stream. Such a process may be integrated
with a hydrocarbon (e.g. ethylene) (steam) cracker so that hydrogen
from the cracker may be used to saturate and cleave the compounds
comprising two or more aromatic rings and the C2-C4 alkane stream
may be fed to the hydrocarbon cracker, or may be integrated with a
hydrocarbon cracker (e.g. steam cracker) and an ethyl benzene unit,
that is to treat the heavy residues from processing oil sands, tar
sands, shale as or any oil having a high content of fused ring
aromatic compounds to produce a stream suitable for petrochemical
production.
[0026] US2005/0101814 relates to a process for improving the
paraffin content of a feedstock to a steam cracking unit,
comprising: passing a feedstream comprising C5 through C9
hydrocarbons including C5 through C9 normal paraffins into a ring
opening reactor, the ring opening reactor comprising a catalyst
operated at conditions to convert aromatic hydrocarbons to
naphtenes and a catalyst operated at conditions to convert
naphtenes to paraffins, and producing a second feedstream; and
passing at least a portion of the second feedstream to a steam
cracking unit.
[0027] U.S. Pat. No. 7,067,448 relates to a process for the
manufacture of n-alkanes from mineral oil fractions and fractions
from thermal or catalytic conversion plants containing cyclic
alkanes, alkenes, cyclic alkenes and/or aromatic compounds. More in
detail, this publication refers to a process for processing mineral
of fractions rich in aromatic compounds, in which the cyclic
alkanes obtained after the hydrogenation of the aromatic compounds
are converted to n-alkanes of a chain length which as far as
possible is less than that of the charged carbons.
[0028] The LCO-process as discussed above relates to full
conversion hydrocracking of LCO to naphtha, in which LCO is a
mono-aromatics and di-aromatics containing stream. A consequence of
the full conversion hydrocracking is that a highly naphthenic, low
octane naphtha is obtained that must be reformed to produce the
octane required for product blending.
[0029] WO2006/122275 relates to a process for upgrading a heavy
hydrocarbon crude oil feedstock into an oil that is less dense or
lighter and contains lower sulphur than the original heavy
hydrocarbon crude oil feedstock while making value added materials
such as olefins and aromatics, which process comprises, inter alia,
the steps of: combining a portion, of the heavy hydrocarbon crude
oil with an oil soluble catalyst to form a reactant mixture,
reacting the pre-treated feedstock under relatively lover hydrogen
pressure to form a product stream, wherein a first portion of the
product stream includes a light oil and a second portion of the
product stream includes a heavy crude oil residue, and a third
portion of the product stream includes a light hydrocarbon gas, and
injecting a portion of the light hydrocarbon gas stream in a
cracking unit to produce streams containing hydrogen and at least
one olefin.
[0030] WO2011005476 relates to a process for the treatment of heavy
oils, including crude oils, vacuum residue, tar sands, bitumen and
vacuum gas oils using a catalytic hydrotreating pre-treatment
process, specifically the use of hydrodemetallization (HDM) and
hydrodesulphurization (HDS) catalysts in series in order to improve
the efficiency of a subsequent coker refinery.
[0031] US2008/194900 relates to an olefins process for steam
cracking an aromatics-containing naphtha stream comprising:
recovering olefins and pyrolysis gasoline streams from a steam
cracking furnace effluent, hydrogenating the pyrolysis gasoline
stream and recovering a C6-C8 stream therefrom, hydrotreating an
aromatics-containing naphtha stream to obtain a naphtha feed,
dearomatizing the C6-C8 stream with the naphtha feed stream in a
common aromatics extraction unit to obtain a raffinate stream; and
feeding the raffinate stream to the steam cracking furnace.
[0032] WO2008/092232 relates to a process for extraction of
chemical components from a feedstock, such as a petroleum, natural
gas condensate, or petrochemical feedstock, such as a whole range
naphtha feedstock comprising the steps of: subjecting the whole
range naphtha feedstock to a desulphurizing process, separating
from the desulphurized whole range naphtha feedstock a C6 to C11
hydrocarbon fraction, recovering from the C6 to C11 hydrocarbon
fraction an aromatics fraction, an aromatics precursors fraction
and a raffinate fraction in an aromatics extraction unit,
converting aromatics cursors in the aromatics precursors fraction
to aromatics, and recovering aromatics from step in the aromatics
extraction edit.
[0033] An object of the present invention is to provide a method
for upgrading heady hydrocarbon feedstock to aromatics (BTXE) and
LPG.
[0034] Another object of the present invention is to provide a
process for the production of light olefins and aromatics from a
heavy hydrocarbon feedstock in which a high yield of aromatics can
be attained.
[0035] Another object of the present invention is to provide a
process for upgrading of crude oil feedstock to petrochemicals with
a high carbon efficiency and hydrogen integration.
[0036] The present invention relates thus to a process for
upgrading refinery heavy hydrocarbons to petrochemicals, comprising
the following steps of:
[0037] (a) feeding a hydrocarbon feedstock to a ring opening
reaction area;
[0038] (b) feeding the effluent from (a) to a separation unit for
producing a gaseous stream comprising light boiling hydrocarbons, a
liquid stream comprising naphtha boiling rare hydrocarbons and a
liquid stream comprising diesel boiling range hydrocarbons;
[0039] (c) feeding said liquid stream comprising naphtha boiling
range hydrocarbons to a hydrocracking unit,
[0040] (d) separating reaction products of said hydrocracking unit
of step (c) into an overhead gas stream, comprising light boiling
hydrocarbons, and a BTX (a mixture benzene, toluene and xylenes)
comprising bottom stream,
[0041] e) feeding the overhead as stream from the hydrocracking
unit of step (d) and the gaseous stream from the separation unit of
step (b) to a steam cracking unit and at least one or more units
chosen from the group of propane dehydrogenation unit, butane
dehydrogenation and combined propane-butane dehydrogenation unit,
preferably after it separating a hydrogen containing stream from
said gas streams.
[0042] The present inventors assume that by combining a
ring-opening process with hydrocracking unit, i.e. a so called
gasoline hydrocracking unit/feed hydrocracking unit ("GHC/FHC") the
overall process no longer produces fuels in addition to LPG and
BTXE but only LPG and BTXE. The latter may also obtained directly
as a purified stream as all co-boilers of BTXE are cracked. The LPG
can be used in steam cracking and/or PDH/BDH. The hydrogen produced
there can be used to feed these hydro processing steps. If needed
hydrodesulphurization (HDS), hydrodenitrogenation (HDN) can be
applied according to the catalyst/process requirements. The term
"hydrocracking" is used herein in its generally accepted sense and
thus may be defined as catalytic cracking process assisted by the
presence of an elevated partial pressure of hydrogen; see e.g.
Alfke et al. (2007). The products of this process are saturated
hydrocarbons and, depending art the reaction conditions such as
temperature, pressure and space velocity and catalyst activity,
aromatic hydrocarbons including BTX.
[0043] The term "LPG" as used herein refers to the,
well-established acronym for the term "liquefied petroleum gas".
LPG generally consists of a blend of C3-C4hydrocarbons i.e. a
mixture of C3 and C4 hydrocarbons.
[0044] The one of the petrochemical products produced in the
process of the present invention is BTX. The term "BTX" as used
herein relates a mixture of benzene, toluene and xylenes.
Preferably, the product produced in the process of the present
invention comprises further useful aromatic hydrocarbons such as
ethyl benzene. Accordingly, the present invention preferably
provides a process for producing a mixture of benzene, toluene
xylenes and ethyl benzene ("BTXE"). The product as produced may be
a physical mixture of the different aromatic hydrocarbons or may be
directly subjected to further separation, e.g. by distillation, to
provide different purified product streams. Such purified product
stream may include a benzene product stream, a toluene product
stream, a xylene product stream and/or an ethyl benzene product
stream. The terms "naphthenic hydrocarbons" or "naphthenes"or
"cycloalkanes" is used herein having its established meaning and
accordingly relates types of alkanes that have one or more rings of
carbon atoms in the chemical structure of their molecules.
[0045] The liquid effluent or even the full reactor effluent from
the ring opening process, preferably after only separating out a
heavier recycle stream containing multi ring components, is fed to
the hydrocracking unit ("GHC/FHC"). This greatly simplifies the
ring-opening process and reduces redundancies in separating units
required. Please note that in another embodiment the liquid
effluent is vaporized before entering the hydrocracking unit. Thus
the, feed to the hydrocracking unit can be liquid phase, vapour
phase or mixed vapour-liquid phase. The hydrogen loop can be
applied around both units, i.e. the ring opening reaction area and
the hydrocracking unit ("GHC/FHC"), with multiple addition and
injection points of hydrogen. According to another embodiment only
the naphtha stream or a portion thereof is sent to the FHC/GHC
reaction section and possibly all heavier material is recycled to
be further converted thus simplifying the flowchart.
[0046] The present process further comprises separating reaction
products of said hydrocracking unit of step (c) into an overhead
gas stream, comprising light boiling hydrocarbons and a BTX
comprising bottom stream. The hydrogen containing gaseous stream
may be separated from the overhead gas stream comprising light
boiling hydrocarbons.
[0047] The present process further preferably comprises feeding the
overhead gas stream from the hydrocracking unit of step (d) and the
gaseous stream from the separation unit of step (b) to another
separation unit and feeding the thus separated streams to said
steam cracking unit and said dehydrogenation unit(s),
[0048] According to the present invention the dehydrogenation
process is a catalytic process and the steam cracking process is a
thermal cracking process.
[0049] According to a preferred embodiment the process further
comprises feeding the overhead stream freed the hydrocracking unit
and the gaseous stream from the separation unit to a steam cracking
unit and one or more units chosen from the group of propane
dehydrogenation unit, butane dehydrogenation and combined
propane-butane dehydrogenation unit.,preferably after separating a
hydrogen containing stream from the gas streams.
[0050] By means of adding ring-opening it is possible to process a
heavier feed than would be possible to send directly to a FHC/GHC
unit. Furthermore, the addition of a separation unit upfront of the
ring opening process allows the FHC/GHC unit to convert any
naphthenics in the feed stream boiling in the naphtha range into
aromatics/BTX. This way a higher BTX yield can be obtained when
compared to ring-opening only because these naphthenics would
otherwise be cracked in the ring-opening process to produce LPG
rather than BTX.
[0051] According to a preferred embodiment the present process
further comprises pretreating the hydrocarbon feedstock in a
splitter unit, from which splitter unit the naphtha boiling range
hydrocarbons are fed directly into the hydrocracking unit and its
heavier fraction is fed into the ring opening reaction area.
[0052] The present process further comprises preferably
pre-treating the hydrocarbon feedstock in an aromatics extraction
unit, from which aromatics extraction unit its aromatic rich stream
is fed into the reaction area for ringopening, wherein the
aromatics extraction unit is chosen from the group of the type of a
distillation unit, the molecular sieve type and the type of a
solvent extraction unit.
[0053] In addition to the splitter as mentioned above yields
towards BTX can be further improved by "pre-cracking" the feed
using hydrocracking technology. Such a preferred process can
produce a highly naphthenic and aromatic naphtha range material
based on the type of feed material that can be processed in the
FHC/GHC section to produce a maximum BTX as again even more
naphthenics are converted to BTX when compared to feeding directly
into a ring-opening process.
[0054] The hydrogen loop for the three reaction sections can be
optimized with respect to purity, cascading, pressure levels. Heavy
unconverted material at the outlet of the ring-opening reactor can
be recycled to either the ring-opening process or to the first
hydrocracking step.
[0055] Thus, the present process further comprises preferably
pre-treating the hydrocarbon feedstock in a pre-hydrocracking unit,
from which pre-hydrocracking unit the gaseous stream comprising LPG
is fed to a steam cracking unit and at least one or more units
chosen from the group of propane dehydrogenation unit, butane
dehydrogenation unit and combined propane-butane dehydrogenation
unit, its heavier hydrocarbon fraction is fed to the ring opening
reaction area and a stream comprising naphtha boiling range
hydrocarbons is fed directly to the hydrocracking unit.
[0056] The present inventors found that in another embodiment the
first pre-hydrocracking step can be replaced by a
hydrodealkylation/reforming process, resulting in a high purity
BTXE stream. As a result even more BTX can be produced compared to
the embodiment of the pre-hydrocracking step because of the
`active` additional aromatics production in the reforming type of
first reactor, which means that not only naphtenes are aromatized
but also some additional ring formation must occur.
[0057] Thus, the present process further comprises preferably
pre-treating the hydrocarbon feedstock in a
hydrodealkylation/reforming type unit, from which
hydrodealkylation/reforming type unit a BTXE stream is obtained,
the gaseous stream comprising LPG is fed to one or more units
chosen from the group of steam cracking unit, propane
dehydrogenation unit, butane dehydrogenation unit an combined
propane-butane dehydrogenation unit, and its heavier hydrocarbon
fraction is fed into the ring opening reaction area.
[0058] The present process further comprises preferably feeding a
bottom stream, e.g. the BTX rich stream of the hydrocracking unit
to a transalkylation unit.
[0059] In addition, the present process further comprises
preferably feeding the liquid stream comprising diesel boiling
range hydrocarbons from the separation unit to an aromatics
saturation unit.
[0060] The present process further comprises preferably feeding at
least one of the gaseous stream from the separation unit, the
gaseous stream from the hydrodealkylation/reforming type unit and
the gaseous stream from the pre-hydrocracking unit to the
hydrocracking unit. According to another embodiment at least one of
a stream from the hydrodealkylation/reforming type unit and a
stream from the pre-hydrocracking unit is sent to the reaction area
for ringopening. Such a stream can be a gaseous stream
[0061] The overhead stream from the hydrocracking unit, the gaseous
stream from the separation unit, and possibly the gaseous streams m
the pre-hydrocracking unit and the hydrodealkylation/reforming type
unit can be separated into individual streams each stream
predominantly comprising C2 paraffins, C3 paraffins and C4
paraffins, respectively, and feeding each individual stream to a
specific furnace section of the steam cracker unit, wherein a
hydrogen containing stream is sent to one or more hydrogen
consuming process units, such as the hydrocracking unit and the,
reaction area for ring opening.
[0062] According to a preferred embodiment the gaseous stream, sent
to the steam cracker unit, is partly sent to a dehydrogenation
unit, wherein it is preferred to send only the C3-C4 fraction to
the dehydrogenation unit, especially as separate C3 and C4 streams,
more preferably as a combined C3+C4 stream.
[0063] Thus the present method comprises the combination of a steam
cracker unit and at least one unit chosen from the group of a
butanes dehydrogenation unit, a propane dehydrogenation unit, a
combined propane-butanes dehydrogenation unit, or a combination of
units thereof to produce a mixed, product stream. This combination
of units provides a high yield of the desired products, namely
olefinic and aromatic petrochemicals. Wherein the portion of the
crude oil converted to LPG is increased significantly.
[0064] According to a preferred embodiment the gaseous streams, for
example the overhead gas stream from the hydrocracking unit of step
(d) and the gaseous stream from the separation unit of step (b),
are separated into one or more streams, wherein the stream
comprising hydrogen is preferably used as a hydrogen source for
hydrocracking purpose, the stream comprising methane is preferably
used as a fuel source, the stream comprising ethane is preferably
used as a feed for the steam cracking unit, the stream comprising
propane is preferably used as a feed for a propane dehydrogenation
unit, a stream comprising butanes is preferably used as a feed for
a butane dehydrogenation unit, a stream comprising C1-minus is
preferably used as a fuel source and/or as a hydrogen source, a
stream comprising C3-minus is preferably used as a feed for a
propane dehydrogenation unit but, according to another embodiment,
also as a feed for the steam cracking unit, a stream comprising
C2-C3 is preferably used as a feed for propane dehydrogenation
unit, but, according to another embodiment, also as a feed for the
steam cracking unit a stream comprising. C1-C3 is preferably used
as a feed for a propane dehydrogenation unit, but, according to
another embodiment, also as a feed for the steam cracking unit, a
stream comprising C1-C4 butanes is preferably used as a feed for a
butane dehydrogenation unit, a stream comprising C2-C4 butanes is
preferably used as a feed for a butane dehydrogenation unit, a
stream comprising C2-minus is preferably as a feed for the steam
cracking unit, a stream comprising C3-C4 is preferably used as a
feed for a propane or butane dehydrogenation unit, or a combined
propane and butane dehydrogenation unit, a stream comprising
C4-minus is preferably used as a feed for a butane dehydrogenation
unit.
[0065] The present process further comprises recovering hydrogen
from the reaction products of one or more units chosen from the
group of steam cracking unit, propane dehydrogenation unit, butane
dehydrogenation unit and combined propane-butane dehydrogenation
unit, and feeding the hydrogen thus recovered to the hydrocracking
unit and the reaction area for ring opening, especially further
comprising recovering hydrogen from the dehydrogenation unit and
feeding the hydrogen thus recovered to any hydrogen consuming unit,
such as the hydrocracking and the reaction area for ring
opening.
[0066] The process conditions prevailing in the reaction area for
ring opening include preferably a temperature from 100[deg.] C. to
500[deg.] C. and a pressure from 2 to 10 MPa together with from 50
to 300 kg of hydrogen per 1,000 kg of feedstock over an aromatic
hydrogenation catalyst and passing the resulting stream to a ring
cleavage unit at a temperature from 200[deg.] C. to 600[deg.] C.
and a pressure from 1 to 12 MPa together with from 50 to 200 kg of
hydrogen per 1,000 kg of the resulting stream over a ring cleavage
catalyst.
[0067] The term "(aromatic) ring opening unit" refers to a refinery
unit for performing a hydrocracking process suitable for converting
a feed that is relatively rich in aromatic hydrocarbon having a
boiling point in the kerosene and gasoil boiling point range to
produce LPG and, depending on the process conditions, a
light-distillate (ARO-derived gasoline). Such an aromatic ring
opening process (ARO process) is for instance described in U.S.
Pat. No. 7,513,988. Accordingly, the ARO process may comprise
aromatic ring saturation at a temperature of 300-500.degree. C., a
pressure of 2-10 MPa together with 10-30 wt-% of hydrogen (in
relation to the hydrocarbon feedstock) in the presence of an
aromatic hydrogenation catalyst and ring cleavage at a temperature,
of 200-600.degree. C., a pressure of 1-12 MPa together with 5-20
wt-% of hydrogen (in relation to the hydrocarbon feedstock) in the
presence of an ring cleavage catalyst, wherein said aromatic ring
saturation and ring cleavage may be performed in one reactor or in
two consecutive reactors. The aromatic hydrogenation catalyst may
be a conventional hydrogenation/hydrotreating catalyst such as a
catalyst comprising a mixture of Ni, W and Mo on a refractory
support, typically alumina. The ring cleavage catalyst comprises a
metallic component and a support, preferably one or more metals
selected from the group consisting of Pd, Rh, Ru, Ir, Os, Cu, Co,
Ni, Pt, Fe, Zn, Ga, In, Mo. W and V. By adapting the residence time
under aromatic ring saturation conditions, the process can be
steered towards full saturation and subsequent cleavage of all
rings (relatively long residence time under aromatic g saturation
conditions) or towards keeping one aromatic ring unsaturated and
subsequently cleavage of all but one ring (relatively short
residence time under aromatic ring saturation conditions). In the
latter case, the ARO process produces a light-distillate
("ARO-gasoline")which is relatively rich in hydrocarbon compounds
having one aromatic ring.
[0068] The process conditions prevailing in the separation unit
include preferably a temperature from 149[deg.]C to 288[deg.]C and
a pressure from 1 MPa to 17.3 Mpa.
[0069] The process conditions prevailing in the hydrocracking unit
include preferably a reaction temperature300-580.degree. C.,
preferable of 450-580.degree. C., more preferable of
470-550.degree. C., a pressure of 0.3-5 MPa gauge, preferably at a
pressure of 0.6-3 MPa gauge, particularly preferable at a pressure
of 1000-2000 kPa gauge most preferable at a pressure of 1-2 MPa
gauge, most preferable at a pressure of 1.2-1.6 Mpa gauge, a Weight
Hourly Space Velocity (WHSV) of 0.1-10 h-1, preferable of 0.2-6
h-1, more preferable of 0.4-2 h-1.
[0070] The process conditions prevailing in the steam cracking unit
include preferably are a reaction temperature around
750-900.degree. C., residence times of 50-1000 milliseconds and a
pressure selected of atmospheric up to 175 kPa gauge.
[0071] A very common process for the conversion of alkanes to
olefins involves "steam cracking" As used herein, the term "steam
cracking" relates to a petrochemical process in which saturated
hydrocarbons are broken down into smaller, often unsaturated,
hydrocarbons such as ethylene and propylene. In steam cracking
gaseous hydrocarbon feeds like ethane, propane and butanes, or
mixtures thereof, (gas cracking) or liquid hydrocarbon feeds like
naphtha or gasoil (liquid cracking) is diluted with steam and
briefly heated in a furnace without the presence of oxygen.
Typically, the reaction temperature is very high, at around
850.degree. C., but the reaction is only allowed to take place very
briefly, usually with residence times of 50-500 milliseconds.
Preferably, the hydrocarbon compounds ethane, propane and butanes
are separately cracked in accordingly specialized furnaces to
ensure cracking at optimal conditions. After the cracking
temperature has been reached, the gas is quickly quenched to stop
the reaction in a transfer line heat exchanger or inside a
quenching header using quench oil. Steam cracking results in the
slow deposition of coke, a form of carbon, on the reactor walls.
Decoking requires the furnace to be isolated from the process and
then a flow of steam or a steam/air mixture is passed through the
furnace coils. This converts the hard solid carbon layer to carbon
monoxide and carbon dioxide. Once this reaction is complete, the
furnace is returned to service. The products produced by steam
cracking depend on the composition of the feed, the hydrocarbon to
steam ratio and on the cracking temperature and furnace residence
time. Light hydrocarbon feeds such as ethane, propane, butanes or
light naphtha give product streams rich in the lighter polymer
grade olefins, including ethylene, propylene, and butadiene.
Heavier hydrocarbon (full range and heavy naphtha and gas oil
fractions) also give products rich in aromatic hydrocarbons.
[0072] To separate the different hydrocarbon compounds produced by
steam cracking the cracked gas is subjected to fractionation unit.
Such fractionation units are well known in the art and may comprise
a so-called gasoline fractionator where the heavy-distillate,
("carbon black oil") and the middle-distillate ("cracked
distillate") are separated from the light-distillate and the gases.
In the subsequent quench tower, most of the light-distillate
produced by steam cracking ("pyrolysis gasoline" or "pygas") may be
separated from the gases by condensing the light-distillate.
Subsequently, the gases may be subjected to multiple compression
stages wherein the remainder of the light distillate may be
separated from the gases between the compression stages. Also acid
gases (CO2 and H2S) may be removed between compression stages. In a
following step, the gases produced by pyrolysis may be partially
condensed over stages of a cascade refrigeration system to about
where only the hydrogen remains in the gaseous phase. The different
hydrocarbon compounds may subsequently be separated by simple
distillation wherein the ethylene, propylene and C4 olefins are the
most important high-value chemicals produced by steam cracking. The
methane produced by steam cracking is generally used as fuel gas,
the hydrogen may be separated and recycled to processes that
consume hydrogen, such as hydrocracking processes. The acetylene
produced by steam cracking preferably is selectively hydrogenated
to ethylene. The alkanes comprised in the cracked gas may be
recycled to the process for converting alkanes to olefins.
[0073] The term "propane dehydrogenation unit" as used herein
relates to petrochemical process unit wherein a propane feedstream
is converted into a product comprising propylene and hydrogen.
Accordingly, the term "butane dehydrogenation unit" relates to a
process unit for converting a butane feedstream into C4 olefins.
Together, processes for the dehydrogenation of lower alkanes such
as propane and butanes are described as lower alkane
dehydrogenation process. Processes for the dehydrogenation of lower
alkanes are well-known in the art and include oxidative
hydrogenation processes and non-oxidative dehydrogenation
processes. In an oxidative dehydrogenation process, the process
heat is provided by partial oxidation of the lower alkane(s) in the
feed. In a non-oxidative dehydrogenation process, which is
preferred in the context of the present invention, the process heat
for the endothermic dehydrogenation reaction is provided by
external heat sources such as hot flue gases obtained by burning of
fuel gas or steam. For instance, the UOP Oleflex process allows for
the dehydrogenation of propane to form propylene and of (iso)butane
to form (iso)butylene (or mixtures thereof) in the presence of a
catalyst containing platinum supported on alumina in a moving bed
reactor: see e.g. U.S. Pat. No. 4,827,072. The Uhde STAR process
allows for the dehydrogenation of propane to form propylene or of
butane to form butylene in the presence of a promoted platinum
catalyst supported on a zinc-alumina spinal; see e.g. U.S. Pat. No.
4,926,005. The STAR process has been recently improved by applying
the principle of oxydehydrogenation. In a secondary adiabatic zone
in the reactor part of the hydrogen from the intermediate product
is selectively converted with added oxygen to form water. This
shifts the thermodynamic equilibrium to higher conversion and
achieve higher yield. Also the external heat required for the
endothermic dehydrogenation reaction is partly supplied by the
exothermic hydrogen conversion. The Lummus Catofin process employs
a number of fixed bed reactors operating on a cyclical basis. The
catalyst is activated alumina impregnated with 18-20 wt-% chromium;
see e.g. EP 0 192 058 Al and GB 2 162 082 A. The Catofin process is
reported to be robust and capable of handling impurities which
would poison a platinum catalyst. The products produced by a butane
dehydrogenation process depends on the nature of the butane feed
and the butane dehydrogenation process used. Also the Catofin
process allows for the dehydrogenation of butane to form butylene:
see e.g. U.S. Pat. No. 7,622,623.
[0074] The hydrocarbon feedstock of step (a) is chosen form the
group of shale oil, crude oil, kerosene, diesel, atmospheric gas
oil (AGO), gas condensates, waxes, crude contaminated naphtha,
vacuum gas oil (VGO), vacuum residue, atmospheric residue, naphtha
and pre-treated naphtha, or a combination thereof. Other preferred
feed stocks are light cycle oil/heavy cycle oil (LCO/HCO), coker
naphtha and diesel, FCC naphtha, and diesel and even slurry
oil.
[0075] The invention will be described in further detail below and
in conjunction with the attached drawings in which the same or
similar elements are referred to by the same number, and where:
[0076] FIG. 1 is a schematic illustration of an embodiment of the
process of the invention.
[0077] FIG. 2 is another embodiment of the process of the
invention.
[0078] FIG. 3 is another embodiment of the process of the
invention.
[0079] FIG. 4 is another embodiment of the process of the
invention.
[0080] FIG. 5 is another embodiment of the process of the
invention.
[0081] FIG. 6 is another embodiment of the process of the
invention.
[0082] Referring now to the process and apparatus schematically
depicted in FIG. 1, there is shown a process 101 for upgrading
refinery heavy hydrocarbons to petrochemicals. Hydrocarbon
feedstock 5 is sent to a ring opening reaction area 1 and its
effluent 17 sent to a separation unit 2 producing a gaseous stream
4 comprising LPG, liquid stream 18 comprising naphtha boiling range
hydrocarbons and a liquid stream 15 comprising diesel boiling
range, hydrocarbons. Stream 15, comprising diesel boiling range
hydrocarbons, is preferably recycled to the inlet of ringopening
reaction area 1. Stream 18 comprising naphtha boiling range
hydrocarbons is sent to a hydrocracking unit 3 producing an
overhead gas stream 9, comprising LPG, and a bottom stream 11,
comprising aromatic hydrocarbons, such as BTX. Stream 4 and stream
9 are combined as stream 10 and further processed in a steam
cracker unit and a dehydrogenation unit, chosen from the group of a
propane dehydrogenation unit, a butane dehydrogenation unit and a
combined propane/butane dehydrogenation unit. In this embodiment
gaseous stream 10 is first separated in a separation unit 20 into
individual streams 24, 25 26. However, the number of streams is not
limited. The light hydrocarbons fraction 24 is sent to a gas steam
cracker unit 22 and its effluent is sent to a further separation
section 23, which section 23 may comprise several separation units.
Streams 25, 26 are processed in a dehydrogenation section 21, this
section 21 may comprise several dehydrogenation units, such as a
propane dehydrogenation unit, a butane dehydrogenation unit and a
combined propane/butane dehydrogenation unit. The dehydrogenated
effluent 28 is sent to separation unit 23 and separated into
individual streams 29, 30, for example olefins comprising streams.
However, the number of streams is not limited. According to another
embodiment stream 4 can be (partly) sent to hydrocracking unit 3
producing a overhead gas stream 9, comprising LPG, and a bottom
stream 11 comprising aromatic hydrocarbons, such as BTX.
[0083] According to process 201 (see FIG. 2) a hydrocarbon
feedstock 5 is pre-treated in a splitter unit 5 producing stream
16, comprising naphtha boiling range hydrocarbons. Stream 16 is
directly sent to hydrocracking unit 3. The effluent of splitter
unit 5, comprising heavy hydrocarbons, is sent to a ringopening
reaction area 1. Ringopening reaction area 1 produces an effluent
stream 17. Stream 17 is sent to a separation unit 2 producing a
gaseous stream 4 comprising LPG, liquid stream 18 comprising
naphtha boiling range hydrocarbons and a stream 15 comprising
diesel boiling range hydrocarbons. Stream 15 comprising diesel
boiling range hydrocarbons is preferably recycled to the inlet of
ringopening reaction area 1. Stream 18 is further converted in
hydrocracking unit 3 producing an overhead gas stream 9, comprising
LPG and a bottom stream 11 comprising BTX. Stream 4 and stream 9
are combined as stream 10 and can be further processed as mentioned
in the discussion of FIG. 1 above. According to another embodiment
stream 4 can be (partly) sent to hydrocracking unit 3 producing an
overhead gas stream 9, comprising LPG, and a bottom stream 11,
comprising aromatic hydrocarbons, such as BTX.
[0084] In addition to splitter unit 5 as discussed above in FIG. 2
yields towards BTX can be further improved by providing
pre-hydrocracking unit 6. According to the process 301 of FIG. 3
hydrocarbon feedstock 5 is pre-hydrocracked in pre-hydrocracking
unit 6 producing a gaseous stream 13 and a bottom stream 8,
comprising naphtha. Stream 8 is sent directly to hydrocracking unit
3. The heavy fraction coming from, the pre-hydrocracking unit 6 is
sent to a ringopening reaction area 1, in ringopening reaction area
1 the hydrocarbons coming from preheat hydrocracking unit 6 are
converted in effluent 17. Effluent 17 is sent to a separation unit
2 producing a gaseous stream 4 comprising LPG, liquid stream 18
comprising naphtha boiling range hydrocarbons and a stream 15
comprising diesel boiling range hydrocarbons. Stream 15 comprising
diesel boiling range hydrocarbons is recycled o the inlet of
pre-hydrocracking unit 6. Stream 18 is fed to a hydrocracking unit
3 producing an overhead gas stream 9, comprising LPG, and a bottom
stream 11, comprising BTX. Gaseous streams 4 and 9 are combined as
stream 10, which stream 10 can be further processed as discussed
above in FIG. 1. According to another embodiment stream 4 and
stream 13 can be (partly) sent to hydrocracking unit 3 producing an
overhead gas stream 9, comprising LPG, and a bottom stream
comprising aromatic hydrocarbons, such as BTX. In addition stream
13 can be (partly) sent to ringopening reaction area 1.
[0085] According to another embodiment, now process 401 in FIG. 4,
the first hydrocracking step as discussed above in FIG. 3 can be
replaced by a hydrodealkylation unit 7, from which unit 7 a BTXE
stream 12 is obtained and a gaseous stream 14 comprising LPG. The
heavier fraction coming from unit 7 is sent to a ringopening
reaction area 1 and results in an effluent 17. Effluent 17 coming
from ringopening reaction area 1 is sent to a separation unit 2
producing a gaseous stream 4 comprising LPG, liquid stream 18
comprising naphtha boiling range hydrocarbons and a stream 15
comprising diesel boiling range hydrocarbons. Stream 15 comprising
diesel boiling range hydrocarbons is recycled to the inlet of
hydrodealkylation unit 7. Stream 18 is sent to a hydrocracking unit
3, producing an overhead gas stream 9, comprising LPG and a bottom
stream 11, comprising BTX. The BTXE rich stream produced in unit 7
can be further treated in hydrocracking unit 3. The gaseous streams
14, 4 and 9 are combined as stream 10, which stream can be further
processed as discussed in FIG. 1 above. According to another
embodiment (not shown) stream 4 and stream 14 can be (partly) sent
to hydrocracking unit 3 producing an overhead gas stream 9,
comprising LPG, and a bottom stream 11, comprising aromatic
hydrocarbons, such as BTX. In addition stream 14 can be (partly)
sent to ringopening reaction area 1.
[0086] In a preferred embodiment, as shown in FIG. 5, according to
process 501 f or upgrading refinery heavy hydrocarbons to
petrochemicals a hydrocarbon feedstock 5 is sent to a ring opening
reaction area 1 and its effluent 17 is sent to a separation unit 2
producing a gaseous stream 4 comprising LPG, liquid stream 18
comprising naphtha boiling range hydrocarbons and a liquid stream
15 comprising diesel boiling range hydrocarbons. Stream 15
comprising diesel boiling range hydrocarbons can be (partly)
recycled to the inlet of ringopening reaction area 1. FIG. 5 also
shows that stream 15 comprising diesel boiling range hydrocarbons
sent as stream 49 to an aromatics saturation unit 50 producing
stream 51. The remaining process units and streams are similar to
those mentioned in FIG. 1 above. According to another embodiment
stream can be (partly) sent to hydrocracking unit 3 producing an
overhead gas stream 9, comprising LPG, and a bottom stream 11,
comprising aromatic hydrocarbons, such as BTX.
[0087] According to another preferred embodiment, at least a
portion of the benzene and toluene, and the 9 and 10 carbon number
aromatic compounds are introduced into a transalkylation zone.
According to this embodiment, shown in FIG. 6 as process 601,
stream 11 is introduced into a transalkylation zone 60 to enhance
the production of xylene compounds resulting in a stream 62. A once
through hydrogen-rich gaseous stream 61 is also introduced into the
transalkylation zone 60. This gaseous stream 61 can be obtained
from other hydrogen producing units, such as hydrogen recovered
from the reaction products of steam cracking unit and
dehydrogenation unit. Operating conditions preferably employed in
the transalkylation zone include a temperature from 177[deg.]C to
525<0>C and a liquid hourly space velocity in the range from
0.2 to 10 hr. Any suitable transalkylation catalyst may be utilized
in the transalkylation zone. Preferred transalkylation catalysts
contain a molecular sieve, a refractory inorganic oxide and a
reduced non-framework weak metal. The preferred molecular sieves
are zeolitic aluminosilicates, such as MFI types of zeolites, which
may be any of those which have a silica to alumina ratio greater
than 10 and a pore diameter of 5 to 8 angstroms. According to
another embodiment stream 4 can be (partly) sent to hydrocracking
unit 3 producing an overhead gas stream 9, comprising LPG, and a
bottom stream 11 comprising aromatic hydrocarbons such as BTX.
EXAMPLES
[0088] The process scheme used here is in accordance with the one
shown in FIG. 1. A hydrocarbon feedstock 5 is fed into a reaction
area for ring opening 1 and its reaction products 17, which are
generated from the reaction area, are separated by unit 2 into an
overhead stream 4, a side stream 18 and a bottom stream 15. The
side stream 18 is fed into a gasoline hydrocracker (GHC) unit 3,
wherein the reaction products of the GHC unit 3 are separated into
an overhead gas stream 9, comprising light components such C2-C4
paraffins, hydrogen and methane, and a stream 1 comprising
predominantly aromatic hydrocarbon compounds and non-aromatic
hydrocarbon compounds. The overhead gas stream 9 from the gasoline
hydrocracker (GHC) unit 3 is combined with stream 4 originating
from unit 2.
[0089] According to case 1 (example according to the invention)
kerosene as feedstock is sent to a reaction area for ring opening
and the side stream thereof is sent a gasoline hydrocracker (GHC)
unit, the LPG fraction is separated from the overhead of unit
2.
[0090] According to case 2 (example according to the invention)
light vacuum gasoil (LVGO) as feedstock is sent to a reaction area
for ring opening and the side stream thereof is sent to a gasoline
hydrocracker (GHC) unit, the LPG fraction is separated from
overhead of unit 2.
[0091] The characteristics of kerosene and LVGO can be found in
Table 1. Table 2 shows the distribution of monoaromatics and
aromatic molecules with more than one ring (Di+ aromatics) in the
feeds. Table 3 shows the battery limit product slate (wt, % of
feedstock).
TABLE-US-00001 TABLE 1 characteristics of kerosene and LVGO
Kerosene LVGO n-paraffins wt-% 23.7 18.3 i-paraffins wt-% 17.9 13.8
Naphthenes wt-% 37.4 35.8 Aromatics wt-% 21.0 32.0 Density 60F Kg/L
0.810 0.913 IBP .degree. C. 174 306 BP10 .degree. C. 196 345 BP30
.degree. C. 206 367 BP50 .degree. C. 216 384 BP70 .degree. C. 226
404 BP90 .degree. C. 242 441 FBP .degree. C. 266 493
TABLE-US-00002 TABLE 2 Classification of aromatic molecules as
function of number of aromatic rings in kerosene and LVGO Kerosene
LVGO Total Aromatics wt.-% of feed 21.0 32.0 Monoaromatics wt.-% of
feed 12.5 9.0 Di+ aromatics wt.-% of feed 8.5 23.0
TABLE-US-00003 TABLE 3 Battery limit product slate (wt. % of
feedstock) COMPONENT Case 1: KEROSENE Case 2: LVGO LPG 87.8 89.4
Ethane 24.8 25.3 Propane 54.1 55.1 n-butane 7.1 7.2 Iso-butane 1.8
1.8 BTX 12.2 10.6 Benzene 3.3 2.9 Toluene 5.9 5.1 Xylenes 3.0
2.6
[0092] The data presented above show that the presence of a
reaction area or ring opening and gasoline hydrocracking (GHC) of
the feeds converts multi-ring aromatic molecules into more valuable
single-ring aromatics and LPG. Additionally, BTX is also obtained
from the dehydrogenation of naphthenes into mono-ring
aromatics.
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