U.S. patent application number 15/848666 was filed with the patent office on 2018-05-03 for system for upgrading residuum hydrocarbons.
This patent application is currently assigned to Lummus Technology Inc.. The applicant listed for this patent is Lummus Technology Inc.. Invention is credited to Mario C. Baldassari, Marvin I. Greene, Ujjal K. Mukherjee, Ann-Marie Olsen.
Application Number | 20180119027 15/848666 |
Document ID | / |
Family ID | 51259785 |
Filed Date | 2018-05-03 |
United States Patent
Application |
20180119027 |
Kind Code |
A1 |
Baldassari; Mario C. ; et
al. |
May 3, 2018 |
SYSTEM FOR UPGRADING RESIDUUM HYDROCARBONS
Abstract
A process for upgrading residuum hydrocarbons is disclosed. The
process may include: contacting a residuum hydrocarbon fraction and
hydrogen with a first hydroconversion catalyst in a first ebullated
bed hydroconversion reactor system; recovering a first effluent
from the first ebullated bed hydroconversion reactor system;
solvent deasphalting a vacuum residuum fraction to produce a
deasphalted oil fraction and an asphalt fraction; contacting the
deasphalted oil fraction and hydrogen with a second hydroconversion
catalyst in a second hydroconversion reactor system; recovering a
second effluent from the second hydroconversion reactor system; and
fractionating the first effluent from the first ebullated bed
hydroconversion reactor system and the second effluent from the
second hydroconversion reactor system to recover one or more
hydrocarbon fractions and the vacuum residuum fraction in a common
fractionation system.
Inventors: |
Baldassari; Mario C.;
(Morris Plains, NJ) ; Mukherjee; Ujjal K.;
(Montclair, NJ) ; Olsen; Ann-Marie; (Granite
Springs, NY) ; Greene; Marvin I.; (Clifton,
NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Lummus Technology Inc. |
Bloomfield |
NJ |
US |
|
|
Assignee: |
Lummus Technology Inc.
Bloomfield
NJ
|
Family ID: |
51259785 |
Appl. No.: |
15/848666 |
Filed: |
December 20, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13758554 |
Feb 4, 2013 |
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15848666 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10G 2300/802 20130101;
C10G 47/26 20130101; C10G 67/00 20130101; C10G 67/049 20130101;
C10G 21/003 20130101 |
International
Class: |
C10G 21/00 20060101
C10G021/00; C10G 67/00 20060101 C10G067/00; C10G 47/26 20060101
C10G047/26; C10G 67/04 20060101 C10G067/04 |
Claims
1. A system for upgrading residuum hydrocarbons, the system
comprising: a first ebullated bed hydroconversion reactor system
for contacting a residuum hydrocarbon fraction and hydrogen to
produce a first effluent; a second ebullated bed hydroconversion
reactor system for contacting a deasphalted oil fraction and
hydrogen to produce a second effluent; and a first fractionation
unit to fractionate the first effluent and the second effluent to
recover one or more hydrocarbon fractions comprising a vacuum
residuum fraction; a solvent deasphalting unit to solvent deasphalt
the vacuum residuum fraction to produce the deasphalted oil
fraction and an asphalt fraction; a third ebullated bed
hydroconversion reactor system for contacting the asphalt fraction
and hydrogen to produce a third effluent; and a second
fractionation unit to fractionate the third effluent to recover one
or more hydrocarbon fractions.
2. The system of claim 1, wherein the fractionation unit is fluidly
coupled to at least one of the solvent deasphalting unit, a vacuum
distillation system, the first ebullated bed hydroconversion
reactor system, the second ebullated bed hydroconversion reactor
system, and the third ebullated bed hydroconversion reactor
system.
3. The system of claim 1, wherein the first ebullated bed
hydroconversion reactor system, the second ebullated bed
hydroconversion reactor system, and the third ebullated bed
hydroconversion reactor system operate at different severities.
4. The system of claim 1, wherein the first fractionation unit
further comprises a high pressure-high temperature separator.
5. The system of claim 1, wherein the first fractionation unit
further produces a heavy gas oil fraction which is sent to the
solvent deasphalting unit.
6. The system of claim 1, wherein the first fractionation unit and
the second fractionation unit are a single unit.
7. A system for upgrading residuum hydrocarbons, the system
comprising: a first ebullated bed hydroconversion reactor system
for contacting a residuum hydrocarbon fraction and hydrogen to
produce a first effluent; a solvent deasphalting unit to solvent
deasphalt a vacuum residuum fraction to produce a deasphalted oil
fraction and an asphalt fraction; a second ebullated bed
hydroconversion reactor system for contacting the deasphalted oil
fraction and hydrogen to produce a second effluent; and a separator
to separate a combined fraction of the first effluent and the
second effluent to recover a liquid fraction and a vapor fraction;
a first fractionation unit to fractionate the liquid fraction to
recover the vacuum residuum fraction; a fixed bed hydroconversion
reactor system for contacting the vapor fraction to produce a third
effluent; a second fractionation unit to fractionate the third
effluent to recover one or more hydrocarbon fractions; a third
ebullated bed hydroconversion reactor system for contacting the
asphalt fraction and hydrogen to produce a third effluent; and a
third fractionation unit to fractionate the third effluent to
recover one or more hydrocarbon fractions.
8. The system of claim 10, wherein the first fractionation unit is
a vacuum distillation unit.
9. A system for upgrading residuum hydrocarbons, the system
comprising: a first ebullated bed hydroconversion reactor system
for contacting a residuum hydrocarbon fraction and hydrogen to
produce a first effluent; a solvent deasphalting unit to solvent
deasphalt a vacuum residuum fraction to produce a deasphalted oil
fraction and an asphalt fraction; a second ebullated bed
hydroconversion reactor system for contacting the deasphalted oil
fraction and hydrogen to produce a second effluent; and a first
fractionation unit to fractionate the first effluent and the second
effluent to recover one or more hydrocarbon fractions and the
vacuum residuum fraction; a third ebullated bed hydroconversion
reactor system for contacting the asphalt fraction and hydrogen to
produce a third effluent; a separator to separate the third
effluent and recover a liquid fraction and a vapor fraction; a
second fractionation unit to fractionate the liquid traction to
recover the vacuum residuum fraction; a fixed bed hydroconversion
reactor system for contacting the vapor fraction to produce a
fourth effluent; and a third fractionation unit to fractionate the
fourth effluent recover one or more hydrocarbon fractions.
10. The system of claim 12, wherein the second fractionation unit
is an atmospheric distillation unit.
11. The system of claim 12, wherein the third fractionation unit is
a vacuum distillation unit.
Description
FIELD OF THE DISCLOSURE
[0001] Embodiments disclosed herein relate generally to
hydroconversion processes, including processes for hydrocracking
residue and other heavy hydrocarbon fractions. More specifically,
embodiments disclosed herein relate to hydrocracking of a residuum
hydrocarbon feedstock, solvent deasphalting of the unconverted
residuum hydrocarbon feedstock, processing the resulting
hydrocracked deasphalted oil in a separate residue hydrocracking
unit, and processing the pitch from the solvent deasphalting unit
in a separate residue hydrocracking unit.
BACKGROUND
[0002] As the worldwide demand for gasoline and other light
refinery products has steadily increased, there has been a
significant trend toward conversion of higher boiling compounds to
lower boiling ones. To meet the increasing demand for distillate
fuels increased, refiners have investigated various reactors, such
as hydrocracking reactors, residual desulfurization units (RDS),
and solvent deasphalting (SDA) units, to convert Residuum, Vacuum
Gas Oil (VGO) and other heavy petroleum feedstocks to jet and
diesel fuels.
[0003] Catalysts have been developed that exhibited excellent
distillate selectivity, reasonable conversion activity and
stability for heavier feedstocks. The conversion rates attainable
by the various processes are limited, however. For example, RDS
units alone can produce a 1 wt % sulfur fuel from high sulfur
residua, but conversions are generally limited to about 35% to 40%,
Others have proposed to use SDA units to solvent deasphalt the
residuum feed and process the deasphalted oil only in a Residuum
Hydrocracking Unit (RHU). Also, others have processed the
unconverted vacuum residuum from a RHU in an SDA unit and recycled
the deasphalted oil (DAO) back to the front end of the RHU. Still
others have proposed to process the SDA pitch directly in a RHU.
Nonetheless, economic processes to achieve high hydrocarbon
conversions and sulfur removal are desired.
SUMMARY
[0004] In one aspect, embodiments disclosed herein relate to a
process for upgrading residuum hydrocarbons. The process may
include the following steps: contacting a residuum hydrocarbon
fraction and hydrogen with a first hydroconversion catalyst in a
first ebullated bed hydroconversion reactor system; recovering a
first effluent from the first ebullated bed hydroconversion reactor
system; solvent deasphalting a vacuum residuum fraction to produce
a deasphalted oil fraction and an asphalt fraction; contacting the
deasphalted oil fraction and hydrogen with a second hydroconversion
catalyst in a second hydroconversion reactor system; recovering a
second effluent from the second hydroconversion reactor system; and
fractionating the first effluent from the first ebullated bed
hydroconversion reactor system and the second effluent from the
second hydroconversion reactor system to recover one or more
hydrocarbon fractions and the vacuum residuum fraction in a common
fractionation system.
[0005] In another aspect, embodiments disclosed herein relate to a
system for upgrading residuum hydrocarbons. The system may include
the following: a first ebullated bed hydroconversion reactor system
for contacting a residuum hydrocarbon fraction and hydrogen with a
first hydroconversion catalyst to produce a first effluent; a
solvent deasphalting unit to solvent deasphalt a vacuum residuum
fraction to produce a deasphalted oil fraction and an asphalt
fraction; a second hydroconversion reactor system for contacting
the deasphalted oil fraction and hydrogen with a second
hydroconversion catalyst to produce a second effluent; and a
fractionation unit to fractionate the first effluent and the second
effluent to recover one or more hydrocarbon fractions and the
vacuum residuum fraction.
[0006] In another aspect, embodiments disclosed herein relate to a
system for upgrading residuum hydrocarbons. The system may include
the following: a first ebullated bed hydroconversion reactor system
for contacting a residuum hydrocarbon fraction and hydrogen with a
first hydroconversion catalyst to produce a first effluent; a
solvent deasphalting unit to solvent deasphalt a vacuum residuum
fraction to produce a deasphalted oil fraction and an asphalt
fraction; a second hydroconversion reactor system for contacting
the deasphalted oil fraction and hydrogen with a second
hydroconversion catalyst to produce a second effluent; and a
separator to separate a combined fraction of the first effluent and
the second effluent to recover a liquid fraction and a vapor
fraction; a fractionation unit to fractionate the liquid to recover
the vacuum residuum fraction; a third hydroconversion reactor
system for contacting the vapor fraction with a third
hydroconversion catalyst to produce a third effluent; and a
fractionation unit to fractionate the third effluent to recover one
or more hydrocarbon fractions.
[0007] In another aspect, embodiments disclosed herein relate to a
system for upgrading residuum hydrocarbons. The system may include
the following: a first ebullated bed hydroconversion reactor system
for contacting a residuum hydrocarbon fraction and hydrogen with a
first hydroconversion catalyst to produce a first effluent; a
solvent deasphalting unit to solvent deasphalt a vacuum residuum
fraction to produce a deasphalted oil fraction and an asphalt
fraction; a second hydroconversion reactor system for contacting
the deasphalted oil fraction and hydrogen with a second
hydroconversion catalyst to produce a second effluent; and a first
fractionation unit to fractionate the first effluent and the second
effluent to recover one or more hydrocarbon fractions and the
vacuum residuum fraction; a third ebullated bed hydroconversion
reactor system for contacting the asphalt fraction and hydrogen to
produce third effluent; a separator to separate the third effluent
and recover a liquid fraction and a vapor fraction; a second
fractionation unit to fractionate the liquid to recover the vacuum
residuum fraction; a fourth hydroconversion reactor system for
contacting the vapor fraction with a fourth hydroconversion
catalyst to produce a fourth effluent; and a third fractionation
unit to fractionate the fourth effluent to recover one or more
hydrocarbon fractions.
[0008] Other aspects and advantages will be apparent from the
following description and the appended claims.
BRIEF DESCRIPTION OF DRAWINGS
[0009] FIG. 1 is a simplified process flow diagram of a process for
upgrading residuum hydrocarbon feedstocks according to embodiments
disclosed herein.
[0010] FIG. 2 is a simplified process flow diagram of a process for
an integrated hydroprocessing reactor system to be used with a
process for upgrading residuum hydrocarbon feedstocks according to
embodiments disclosed herein.
[0011] FIG. 3 is a simplified alternate process flow diagram of a
process for an integrated hydroprocessing reactor system to be used
with a process for upgrading residuum hydrocarbon feedstocks
according to embodiments disclosed herein.
DETAILED DESCRIPTION
[0012] In one aspect, embodiments herein relate generally to
hydroconversion processes, including processes for hydrocracking
residue and other heavy hydrocarbon fractions. More specifically,
embodiments disclosed herein relate to hydrocracking of a residuum
hydrocarbon feedstock, solvent deasphalting of the unconverted
residuum hydrocarbon feedstock, processing the resulting
hydrocracked deasphalted oil in a separate residue hydrocracking
unit, and processing the pitch from the solvent deasphalting in a
separate residue hydrocracking unit.
[0013] Hydroconversion processes disclosed herein may be used for
reacting residuum hydrocarbon feedstocks at conditions of elevated
temperatures and pressures in the presence of hydrogen and one or
more hydroconversion catalyst to convert the feedstock to lower
molecular weight products with reduced contaminant (such as sulfur
and/or nitrogen) levels. Hydroconversion processes may include, for
example, hydrogenation, desulfurization, denitrogenation, cracking,
conversion, demetallization, and removal of metals, Conradson
Carbon Residue (CCR) or asphaltenes removal, etc.
[0014] As used herein, residuum hydrocarbon fractions, or like
terms referring to residuum hydrocarbons, are defined as a
hydrocarbon fraction having boiling points or a boiling range above
about 340.degree. C. but could also include whole heavy crude
processing. Residuum hydrocarbon feedstocks that may be used with
processes disclosed herein may include various refinery and other
hydrocarbon streams such as petroleum atmospheric or vacuum
residua, deasphalted oils, deasphalter pitch, hydrocracked
atmospheric tower or vacuum tower bottoms, straight run vacuum gas
oils, hydrocracked vacuum gas oils, fluid catalytically cracked
(FCC) slurry oils, vacuum gas oils from an ebullated bed
hydrocracking process, shale-derived oils, coal-derived oils, tar
sands bitumen, tall oils, bio-derived crude oils, black oils, as
well as other similar hydrocarbon streams, or a combination of
these, each of which may be straight run, process derived,
hydrocracked, partially desulfurized, and/or partially demetallized
streams. In some embodiments, residuum hydrocarbon fractions may
include hydrocarbons having a normal boiling point of at least
480.degree. C., at least 524.degree. C., or at least 565.degree.
C.
[0015] Referring now to FIG. 1, a residuum hydrocarbon fraction
(residuum) 10 and hydrogen 21 may be fed to an ebullated bed
reactor system 42, which may include one or more ebullated bed
reactors arranged in series or parallel, where the hydrocarbons and
hydrogen are contacted with a hydroconversion catalyst to react at
least a portion of the residuum with hydrogen to form lighter
hydrocarbons, demetallize the metals contained in residuum, remove
Conradson Carbon Residue, or otherwise convert the residuum to
useful products.
[0016] Reactors in ebullated bed reactor 42 may be operated at
temperatures in the range from about 380.degree. C. to about
450.degree. C., hydrogen partial pressures in the range from about
70 bara to about 170 bara, and liquid hourly space velocities
(LHSV) in the range from about 0.2 h.sup.-1 to about 2.0 h.sup.-1.
Within the ebullated bed reactors, the catalyst may be back mixed
and maintained in random motion by the recirculation of the liquid
product. This may be accomplished by first separating the
recirculated oil from the gaseous products. The oil may then be
recirculated by means of an external pump, or, as illustrated, by a
pump having an impeller mounted in the bottom head of the
reactor.
[0017] Target conversions in ebullated bed reactor system 42 may be
in the range from about 30 wt % to about 75 wt %, depending upon
the feedstock being processed. In any event, target conversions
should be maintained below the level where sediment formation
becomes excessive and thereby prevent continuity of operations. In
addition to converting the residuum hydrocarbons to lighter
hydrocarbons, sulfur removal may be in the range from about 40 wt %
to about 65 wt %, metals removal may be in the range from about 40
wt % to 65 wt % and Conradson Carbon Residue (CCR) removal may be
in the range from about 30 wt % to about 60 wt %.
[0018] Reactor severity may be defined as the catalyst average
temperature in degrees Fahrenheit of the catalysts loaded in the
one or more ebullated bed hydrocracking reactors multiplied by the
average hydrogen partial pressure of the ebullated bed
hydrocracking reactors in Bar absolute and divided by the LHSV in
the ebullated bed hydrocracking reactors. The reactor severity of
the ebullated bed reactor system 42 may be in the range from about
105,000.degree. F.-Bara-Hr to about 446,000.degree. F.-Bara-Hr.
[0019] Following conversion in ebullated bed reactor system 42, the
partially converted hydrocarbons may be recovered via flow line 44
as a mixed vapor/liquid effluent and fed to a fractionation system
46 to recover one or more hydrocarbon fractions. As illustrated,
fractionation system 46 may be used to recover an offgas 48
containing light hydrocarbon gases and hydrogen sulfide (H.sub.2S),
a light naphtha fraction 50, a heavy naphtha fraction 52, a
kerosene fraction 54, a diesel fraction 56, a light vacuum gas oil
fraction 58, a heavy gas oil fraction 60, and a vacuum residuum
fraction 62. In some embodiments, vacuum residuum fraction 62 may
be recycled for further processing, such as to a solvent
deasphalting (SDA) unit 12, the ebullated bed reactor system 42, or
other reaction units 70, 20 discussed below. When the vacuum
residuum fraction 62 is sent to the SDA unit 12, a portion of the
heavy gas oil fraction 60 may also be routed to the SDA unit
12.
[0020] Fractionation system 46 may include, for example, a high
pressure high temperature (HF/HT) separator to separate the
effluent vapor from the effluent liquids. The separated vapor may
be routed through gas cooling, purification, and recycle gas
compression, or may be first processed through an Integrated
Hydroprocessing Reactor System (IHRS), which may include one or
more additional hydroconversion reactors, alone or in combination
with external distillates and/or distillates generated in the
hydrocracking process, and thereafter routed for gas cooling,
purification, and compression.
[0021] In some embodiments, the vacuum resid fraction 62 is fed to
a Solvent Deasphalting Unit (SDA) 12. In SDA 12, the vacuum
residuum fraction 62 is contacted with a solvent to selectively
dissolve asphaltenes and similar hydrocarbons to produce a
deasphalted oil (DAG) fraction 14 and a pitch fraction 15. In other
embodiments, a portion of the heavy gas oil fraction 60 may also be
fed to the SDA 12.
[0022] Solvent deasphalting may be performed in the SDA 12, for
example, by contacting the residuum hydrocarbon feed with a light
hydrocarbon solvent at temperatures in the range from about
38.degree. C. to about 204.degree. C. and pressures in the range
from about 7 Barg to about 70 barg Solvents useful in the SDA 12
may include C3, C4, C5, C6 and/or C7 hydrocarbons, such as propane,
butane, isobutene, pentane, isopentane, hexane, heptane, or
mixtures thereof, for example. The use of the light hydrocarbon
solvents may provide a high lift (high DAO yield). In some
embodiments, the DAO fraction 14 recovered from the SDA unit 12 may
contain 500 wppm to 5000 wppm asphaltenes heptane insoluble), 50 to
150 wppm metals (such as Ni, V, and others), and 5 wt % to 15 wt %
Conradson Carbon Residue (CCR).
[0023] The DAO fraction 14 and hydrogen 23 may be fed to a
hydrocracking reactor system 20, which may include one or more
hydrocracking reactors, arranged in series or parallel. In reactor
system 20, the DAO fraction 14 may be hydrocracked under hydrogen
partial pressures in the range from about 70 bara to about 180
bara, temperatures in the range from about 390.degree. C. to about
460.degree. C., and LHSV in the range from about 0.1 h.sup.-1 to
about 2.0 h.sup.-1 in the presence of a catalyst. In some
embodiments, operating conditions in hydrocracking reactor system
20 may be similar to those described above for ebullated bed
reactor system 42. In other embodiments, such as where
hydrocracking reactor system 20 includes one or more ebullated bed
reactors, the ebullated bed reactors may be operated at higher
severity conditions than those in reactor system 42, higher
severity referring to a higher temperature, a higher pressure, a
lower space velocity or combinations thereof.
[0024] Depending on the vacuum residuum feedstock properties, the
extent to which metals and Conradson Carbon Residue are removed in
the ebullated bed reactor system 42, and the SDA solvent used, the
DAO recovered may be treated in a fixed bed reaction system or an
ebullated bed reactor system 20, as illustrated, which may be
similar to that described above for ebullated bed reactor system 42
with respect to gas/liquid separations and catalyst recirculation,
among other similarities. A fixed bed reactor system may be used,
for example, where the metals and Conradson Carbon. Residue content
of the DAO is less than 80 wppm and 10 wt %, respectively, such as
less than 50 wppm ad 7 wt %, respectively. An ebullated bed reactor
system may be used, for example, when the metals and Conradson
Carbon Residue contents are higher than those listed above for the
fixed bed reactor system. In either hydrocracking reactor system
20, the number of reactors used may depend on the charge rate, the
overall target residue conversion level, and the level of
conversion attained in ebullated bed reactor system 42, among other
variables. In some embodiments, one or two hydrocracking reactors
may be used in hydrocracking reactor system 20. For an ebullated
bed reactor system 20, the reactor severity may be in the range
from about 215,000.degree. F.-Bara-Hr to about 755,000.degree.
F.-Bara-Hr.
[0025] Following conversion in hydrocracking reactor system 20, the
partially converted hydrocarbons may be recovered via flow line 25
as a mixed vapor/liquid effluent and fed to the fractionation
system 46 to recover one or more hydrocarbon fractions as described
above.
[0026] The pitch fraction 15 and hydrogen 16 may be fed to an
ebullated bed reactor system 70, which may include one or more
ebullated bed reactors, where the hydrocarbons and hydrogen are
contacted with a hydroconversion catalyst to react at least a
portion of the pitch with hydrogen to form lighter hydrocarbons,
demetallize the pitch hydrocarbons, remove Conradson Carbon
Residue, or otherwise convert the pitch to useful products. In some
embodiments, a portion of the residuum hydrocarbon fraction 10 may
also be fed to the ebullated bed reactor system 70. The ratio of
the residuum hydrocarbon fraction 10 in the ebullated bed reactor
system 70 to the ebullated bed reactor system 42 may range from
about 0.1/1 to about 10/1. In other embodiments, the ratio of the
residuum hydrocarbon fraction 10 in the ebullated bed reactor
system 70 to the ebullated bed reactor system 42 may be about
1/1.
[0027] The fixed-bed hydrotreating reactors 66 or 166 may contain
hydroprocessing catalysts tailored to hydrotreating reactions such
as hydrodesulfurization, hydrodenitrogenation, olefins saturation,
hydrodeoxygenation and hydrodearomatization. Alternatively, the
fixed-bed hydrotreating reactors 66 or 166 can contain
hydroprocessing catalysts tailored to hydrocracking reactions. In
other embodiments, the fixed-bed hydrotreating reactors 66 or 166
can contain a mixture of hydrotreating catalysts and hydrocracking
catalysts. Examples of catalysts which may be utilized, but are not
limited to, may be found in U.S. Pat. No. 4,990,243; U.S. Pat. No.
5,215,955; and U.S. Pat. No. 5,177,047, all of which are hereby
incorporated by reference in their entirety. In some embodiments,
the fixed-bed hydrotreating reactors 66 or 166 may not provide any
demetallization and demetallization catalysts may not be
necessary.
[0028] Reactors in the ebullated bed reactor system 70 may be
operated at temperatures in the range from about 380.degree. C. to
about 450.degree. C., hydrogen partial pressures in the range from
about 90 bara to about 170 bara, and liquid hourly space velocities
(LHSV) in the range from about 0.15 h.sup.-1 to about 2.0 h.sup.-1.
Within the ebullated bed reactors, the catalyst may be back mixed
and maintained in random motion by the recirculation of the liquid
product. This may be accomplished by first separating the
recirculated oil from the gaseous products. The oil may then be
recirculated by means of an external pump, or, as illustrated, by a
pump having an impeller mounted in the bottom head of the
reactor.
[0029] Target conversions in the ebullated bed reactor system 70
may be in the range from about 30 wt % to about 75 wt %, depending
upon the feedstock being processed. In any event, target
conversions should be maintained below the level where sediment
formation becomes excessive and thereby prevent continuity of
operations. In addition to converting the residuum hydrocarbons to
lighter hydrocarbons, sulfur removal may be in the range from about
40 wt % to about 65 wt %, metals removal may be in the range from
about 40 wt % to 65 wt % and Conradson Carbon Residue (CCR) removal
may be in the range from about 30 wt % to about 60 wt %.
[0030] The reactor severity of the ebullated bed reactor system 70
may be in the range from about 255,000.degree. F.-Bara-Hr to about
880,000.degree. F.-Bara-Hr.
[0031] Following conversion in the ebullated bed reactor system 70,
the partially converted hydrocarbons may be recovered via flow line
22 as a mixed vapor/liquid effluent and fed to a fractionation
system 24 to recover one or more hydrocarbon fractions. As
illustrated, fractionation system 24 may be used to recover an
offgas 26, a light naphtha fraction 28, a heavy naphtha fraction
30, a kerosene fraction 32, a diesel fraction 34, a light vacuum
gas oil fraction 36, a heavy gas oil fraction 38, and a vacuum
residuum fraction 40. In some embodiments, vacuum residuum fraction
40 may be recycled for further processing. In other embodiments,
vacuum residuum fraction 40 may be blended with a cutter fraction
64 to produce fuel oil. In some embodiments, the fuel oil may have
a sulfur content of less than about 1.5 weight percent.
[0032] Fractionation system 24 may include, for example, a high
pressure high temperature (HP/HT) separator to separate the
effluent vapor from the effluent liquids. The separated vapor may
be routed through gas cooling, purification, and recycle gas
compression, or may be first processed through an integrated
Hydroprocessing Reactor System, alone or in combination with
external distillates and/or distillates generated in the
hydrocracking process and thereafter routed for gas cooling,
purification, and compression.
[0033] The separated liquid from the HP/HT separator may be flashed
and routed to an atmospheric distillation system along with other
distillate products recovered from the gas cooling and purification
section. The atmospheric tower bottoms, such as hydrocarbons having
an initial boiling point of at least about 340.degree. C., such as
an initial boiling point in the range from about 340.degree. C. to
about 427.degree. C., may then be further processed through a
vacuum distillation system to recover vacuum distillates.
[0034] The vacuum tower bottoms product, such as hydrocarbons
having an initial boiling point of at least about 480.degree. C.,
such as an initial boiling point in the range from about
480.degree. C. to about 565.degree. C., may then be routed to
tankage after cooling, such as by direct heat exchange or direct
injection of a portion of the residuum hydrocarbon feed into the
vacuum tower bottoms product.
[0035] Catalysts useful in the ebullated bed reactors or
hydrocracking reactors may include any catalyst useful in the
hydroconversion processes of hydrotreating or hydrocracking a
hydrocarbon feedstock. A hydrotreating catalyst, for example, may
include any catalyst composition that may be used to catalyze the
hydrogenation of hydrocarbon feedstocks to increase its hydrogen
content and/or remove heteroatom contaminants. A hydrocracking
catalyst, for example, may include any catalyst composition that
may be used to catalyze the addition of hydrogen to large or
complex hydrocarbon molecules as well as the cracking of the
molecules to obtain smaller, lower molecular weight molecules.
[0036] In some embodiments, the effluents from the hydrocracking
reactor system 20, the ebullated bed reactor system 42, or the
ebullated bed reactor system 70 may be processed prior to entering
the fractionation system 24 or the fractionation system 46 through
an Integrated Hydroprocessing Reactor System (IHRS). The IHRS is an
inline fixed-bed hydrotreating system utilizing an upstream high
pressure/high temperature vapor/liquid (HP/HT V/L) separator
located between the ebullated-bed hydroprocessing reactor and the
downstream IHRS. The separator allows for a separation between the
unconverted residuum in the liquid effluent of the HP/HT V/L
separator and the overhead vapor products boiling below about
1000.degree. F. normal boiling point which may provide a lower cost
route for further hydrotreating or hydrocracking of the gas oils,
diesel and naphtha fractions formed by cracking of residuum in the
upstream ebullated bed reactor.
[0037] The separated liquid from the HP/HT separator may be flashed
and routed to an atmospheric distillation system along with other
distillate products recovered from the gas cooling and purification
section. The atmospheric tower bottoms, such as hydrocarbons having
an initial boiling point of at least about 340.degree. C., such as
an initial boiling point in the range from about 340.degree. C. to
about 427.degree. C., may then be further processed through a
vacuum distillation system to recover vacuum distillates.
[0038] The vacuum tower bottoms product, such as hydrocarbons
having an initial boiling point of at least about 480.degree. C.,
such as an initial boiling point in the range from about
480.degree. C. to about 565.degree. C., may then be routed to
tankage after cooling, such as by direct heat exchange or direct
injection of a portion of the residuum hydrocarbon feed into the
vacuum tower bottoms product.
[0039] FIGS. 2 and 3 illustrate two embodiments for the IHRS and
are described below, however other embodiments will be obvious to
those skilled in the art as being possible. FIG. 2 illustrates an
embodiment where the IHRS is installed downstream of the blended
stream derived by mixing the partially converted hydrocarbons
recovered via flow line 44 from ebullated bed reactor system 42 and
the partially converted hydrocarbons recovered via flow line 25
from the hydrocracking reactor system 20, FIG. 3 illustrates an
embodiment where the IHRS is installed downstream of the ebullated
bed hydroprocessing reactor 70.
[0040] As shown in FIG. 2, the effluent streams 44 and 25 from
ebullated bed hydroprocessing reactor 42 and the hydrocracking
reactor system 20, respectively, may be cooled in a heat exchanger
(not shown) and fed to a HP/HT V/L separator 61 where a vapor
stream including the light products and distillates boiling below
about 1000.degree. F. normal boiling point and a liquid stream
including unconverted residuum may be separated and processed
separately in downstream equipment. A vapor stream 67 may be fed to
a fixed-bed hydroprocessing reactor 66 to carry out hydrotreating,
hydrocracking or a combination thereof. An effluent stream 68 from
the MRS fixed-bed reactor system 66 is fed to the fractionation
system 46 which recovers an offgas stream 48, light hydrotreated or
hydrocracked naphtha stream 50, heavy hydrotreated or hydrocracked
naphtha stream 52, hydrotreated or hydrocracked kerosene stream 54,
hydrotreated or hydrocracked diesel stream 56, as described above.
The liquid stream 63 may be cooled in a heat exchanger (not shown)
and depressurized in a pressure letdown system (not shown) before
being fed to a vacuum fractionation system 72 which recovers a
light hydrotreated or hydrocracked VGO stream 58, a heavy
hydrotreated or hydrocracked VGO stream 60 and an unconverted
vacuum residuum stream 62. In some embodiments, the vacuum tower
bottoms product stream, such as hydrocarbons having an initial
boiling point of at least about 480.degree. C., such as an initial
boiling point in the range from about 480.degree. C. to about
565.degree. C., may be routed to tankage after cooling, such as by
direct heat exchange or direct injection of a portion of the
residuum hydrocarbon feed into the vacuum tower bottoms
product.
[0041] As shown in FIG. 3, the effluent stream 22 from the
ebullated bed reactor system 70 may be cooled in a heat exchanger
(not shown) and fed to a HP/FIT V/L separator 161 where a vapor
stream including the light products and distillates boiling below
about 1000.degree. F. normal boiling point and a liquid stream
including unconverted residuum may be separated and processed
separately in downstream equipment. A vapor stream 167 is fed to a
fixed-bed hydroprocessing reactor 166 to carry out hydrotreating,
hydrocracking or a combination thereof. An effluent stream 168 from
the IHRS fixed-bed reactor system 166 may be fed to an atmospheric
fractionation system 146 which recovers an offgas stream 26, light
hydrotreated or hydrocracked naphtha stream 28, heavy hydrotreated
or hydrocracked naphtha stream 30, hydrotreated or hydrocracked
kerosene stream 32, hydrotreated or hydrocracked diesel stream 34.
A liquid stream 163 is cooled in a heat exchanger (not shown) and
depressurized in a pressure letdown system (not shown) and may be
fed to a vacuum fractionation system 172 which recovers a light
hydrotreated car hydrocracked VGO stream 36, a heavy hydrotreated
or hydrocracked VGO stream 38 and an unconverted vacuum residuum
stream 40. In some embodiments, the vacuum tower bottoms product
stream, such as hydrocarbons having an initial boiling point of at
least about 480.degree. C., such as an initial boiling point in the
range from about 480.degree. C. to about 565.degree. C., may then
be routed to tankage after cooling, such as by direct heat exchange
or direct injection of a portion of the residuum hydrocarbon feed
into the vacuum tower bottoms product.
[0042] Hydroconversion catalyst compositions for use in the
hydroconversion process according to embodiments disclosed herein
are well known to those skilled in the art and several are
commercially available from W.R. Grace & Co., Criterion
Catalysts & Technologies, and Albemarle, among others. Suitable
hydroconversion catalysts may include one or more elements selected
from Groups 4-12 of the Periodic Table of the Elements. In some
embodiments, hydroconversion catalysts according to embodiments
disclosed herein may comprise, consist of, or consist essentially
of one or more of nickel, cobalt, tungsten, molybdenum and
combinations thereof, either unsupported or supported on a porous
substrate such as silica, alumina, titania, or combinations
thereof. As supplied from a manufacturer or as resulting from a
regeneration process, the hydroconversion catalysts may be in the
form of metal oxides, for example. In some embodiments, the
hydroconversion catalysts may be pre-sulfided and/or
pre-conditioned prior to introduction to the hydrocracking
reactor(s).
[0043] Distillate hydrotreating catalysts that may be useful
include catalyst selected from those elements known to provide
catalytic hydrogenation activity. At least one metal component
selected from Group 840 elements and/or from Group 6 elements is
generally chosen. Group 6 elements may include chromium, molybdenum
and tungsten. Group 8-10 elements may include iron, cobalt, nickel,
ruthenium, rhodium, palladium, osmium, iridium and platinum. The
amount(s) of hydrogenation component(s) in the catalyst suitably
range from about 0.5% to about 10% by weight of Group 8-10 metal
component(s) and from about 5% to about 25% by weight of Group 6
metal component(s), calculated as metal oxide(s) per 100 parts by
weight of total catalyst, where the percentages by weight are based
on the weight of the catalyst before sulfiding. The hydrogenation
components in the catalyst may be in the oxidic and/or the
sulphidic form. If a combination of at least a Group 6 and a Group
8 metal component is present as (mixed) oxides, it will be
subjected to a sulfiding treatment prior to proper use in
hydrocracking. In some embodiments, the catalyst comprises one or
more components of nickel and/or cobalt and one or more components
of molybdenum and/or tungsten or one or more components of platinum
and/or palladium. Catalysts containing nickel and molybdenum,
nickel and tungsten, platinum and/or palladium are useful.
[0044] Residue hydrotreating catalyst that may be useful include
catalysts generally composed of a hydrogenation component, selected
from Group 6 elements (such as molybdenum and/or tungsten) and
Group 840 elements (such as cobalt and/or nickel), or a mixture
thereof, which may be supported on an alumina support. Phosphorous
(Group 15) oxide is optionally present as an active ingredient. A
typical catalyst may contain from 3 to 35 wt % hydrogenation
components, with an alumina binder. The catalyst pellets may range
in size from 1/32 inch to 1/8 inch, and may be of a spherical,
extruded, trilobate or quadrilobate shape. In some embodiments, the
feed passing through the catalyst zone contacts first a catalyst
preselected for metals removal, though some sulfur, nitrogen and
aromatics removal may also occur. Subsequent catalyst layers may be
used for sulfur and nitrogen removal, though they would also be
expected to catalyze the removal of metals and/or cracking
reactions. Catalyst layer(s) for demetallization, when present, may
comprise catalyst(s) having an average pore size ranging from 1.25
to 225 Angstroms and a pore volume ranging from 0.5-1.1 cm.sup.3/g.
Catalyst layer(s) for denitrogenation/desulfurization may comprise
catalyst(s) having an average pore size ranging from 100 to 190
Angstroms with a pore volume of 0.54.1 cm.sup.3/g. U.S. Pat. No.
4,990,243 describes a hydrotreating catalyst having a pore size of
at least about 60 Angstroms, and preferably from about 75 Angstroms
to about 120 Angstroms. A demetallization catalyst useful for the
present process is described, for example, in U.S. Pat. No.
4,976,848, the entire disclosure of which is incorporated herein by
reference for all purposes. Likewise, catalysts useful for
desulfurization of heavy streams are described, for example, in
U.S. Pat. Nos. 5,215,955 and 5,177,047, the entire disclosures of
which are incorporated herein by reference for all purposes.
Catalysts useful for desulfurization of middle distillate, vacuum
gas oil streams and naphtha streams are described, for example, in
U.S. Pat. No. 4,990,243, the entire disclosures of which are
incorporated herein by reference for all purposes.
[0045] Useful residue hydrotreating catalysts include catalysts
having a porous refractory base made up of alumina, silica,
phosphorous, or various combinations of these. One or more types of
catalysts may be used as residue hydrotreating catalyst, and where
two or more catalysts are used, the catalysts may be present in the
reactor zone as layers. The catalysts in the lower layer(s) may
have good demetallization activity. The catalysts may also have
hydrogenation and desulfurization activity, and it may be
advantageous to use large pore size catalysts to maximize the
removal of metals. Catalysts having these characteristics are not
optimal for the removal of Conradson Carbon Residue and sulfur. The
average pore size for catalyst in the lower layer or layers will
usually be at least 60 Angstroms and in many cases will be
considerably larger. The catalyst may contain a metal or
combination of metals such as nickel, molybdenum, or cobalt.
Catalysts useful in the lower layer or layers are described in U.S.
Pat. Nos. 5,071,805, 5,215,955, and 5,472,928. For example, those
catalysts as described in U.S. Pat. No. 5,472,928 and having at
least 20% of the pores in the range of 130 to 170 Angstroms, based
on the nitrogen method, may be useful in the lower catalysts
layer(s). The catalysts present in the upper layer or layers of the
catalyst zone should have greater hydrogenation activity as
compared to catalysts in the lower layer or layers. Consequently,
catalysts useful in the upper layer or layers may be characterized
by smaller pore sizes and greater Conradson Carbon Residue removal,
denitrogenation and desulfurization activity. Typically, the
catalysts will contain metals such as, for example, nickel,
tungsten, and molybdenum to enhance the hydrogenation activity. For
example, those catalysts as described in U.S. Pat. No. 5,472,928
and having at least 30% of the pores in the range of 95 to 135
Angstroms, based on the nitrogen method, may be useful in the upper
catalysts layers. The catalysts may be shaped catalysts or
spherical catalysts. In addition, dense, less friable catalysts may
be used in the upflow fixed catalyst zones to minimize breakage of
the catalyst particles and the entrainment of particulates in the
product recovered from the reactor.
[0046] One skilled in the art will recognize that the various
catalyst layers may not be made up of only a single catalyst, but
may be composed of an intermixture of different catalysts to
achieve the optimal level of metals or Conradson Carbon Residue
removal and desulfurization for that layer. Although some
hydrogenation will occur in the lower portion of the zone, the
removal of Conradson Carbon Residue, nitrogen, and sulfur may take
place primarily in the upper layer or layers. Obviously additional
metals removal also will take place. The specific catalyst or
catalyst mixture selected for each layer, the number of layers in
the zone, the proportional volume in the bed of each layer, and the
specific hydrotreating conditions selected will depend on the
feedstock being processed by the unit, the desired product to be
recovered, as well as commercial considerations such as cost of the
catalyst. All of these parameters are within the skill of a person
engaged in the petroleum refining industry and should not need
further elaboration here.
[0047] While described above with respect to two separate
fractionation systems 24, 46, embodiments disclosed herein also
contemplate fractionating the effluents 22, 44, and 25 in a common
fractionation system. For example, the effluents may be fed into a
common gas cooling, purification, and compression loop before
further processing in an atmospheric tower and a vacuum tower as
described above. The use of a combined separation scheme may
provide for a reduced capital investment, when desired, but may
result in the production of a single fuel oil fraction having a
sulfur level intermediate those achieved by separate
processing.
[0048] As described above, embodiments disclosed herein effectively
processes vacuum residue and intermediate streams through multiple
hydrocracking reactors, each operating at different severities and
processing different feed compositions with a SDA located within
the process, extending the residue conversion limits above those
which can be attained by residue hydrocracking alone. Further, the
higher conversions may be attained using less catalytic reactor
volume as compared to other schemes proposed to achieve similar
conversions. As a result, embodiments disclosed herein may provide
comparable or higher conversions but requiring a lower capital
investment requirement. Further, embodiments disclosed herein may
be used to produce a fuel oil having less than 1 wt % sulfur from a
high sulfur containing residue feed while maximizing overall
conversion.
[0049] The overall processing schemes disclosed herein may be
performed using low reactor volumes while still achieving high
conversions. Likewise, other resulting advantages may include:
reduced catalyst consumption rates due to rejecting metals in the
asphalt from the SDA unit; reduced capital investment; and
elimination or significant reduction in the need for injection of
slurry oil upstream of the ebullated bed reactors, among other
advantages.
[0050] While the disclosure includes a limited number of
embodiments, those skilled in the art, having benefit of this
disclosure, will appreciate that other embodiments may be devised
which do not depart from the scope of the present disclosure.
Accordingly, the scope should be limited only by the attached
claims.
* * * * *