Note: Descriptions are shown in the official language in which they were submitted.
CA 02843515 2015-08-21
HYDROPROCESSED PRODUCT
FIELD
[0001] The invention relates to a hydroprocessed product that can be
produced by
hydroprocessing tar, such as a tar obtained from hydrocarbon pyrolysis. The
invention also
relates to methods for producing such a hydroprocessed product, and the use of
such a
product, e.g., as a fuel oil blending component.
BACKGROUND
[0002] Pyrolysis processes such as steam cracking can be utilized for
converting
saturated hydrocarbon to higher-value products such as light olefin, e.g.,
ethylene and
propylene. Besides these useful products, hydrocarbon pyrolysis can also
produce a
significant amount of relatively low-value products such as steam-cracker tar
("SCT").
[0003] SCT upgrading processes involving conventional catalytic
hydroprocessing
suffer from significant catalyst deactivation. The process can be operated at
a temperature
in the range of from 250 C to 380 C, at a pressure in the range of 5400 kPa to
20,500 kPa,
using catalysts containing one or more of Co, Ni, or Mo; but significant
catalyst coking is
observed. Although catalyst coking can be lessened by operating the process at
an elevated
hydrogen partial pressure, diminished space velocity, and a temperature in the
range of
200 C to 350 C; SCT hydroprocessing under these conditions is undesirable
because
increasing hydrogen partial pressure worsens process economics, as a result of
increased
hydrogen and equipment costs, and because the elevated hydrogen partial
pressure,
diminished space velocity, and reduced temperature range favor undesired
hydrogenation
reactions.
SUMMARY
[0004] In an embodiment, the invention relates to hydroprocessed product,
comprising:
> 10.0 wt. % based on the weight of the hydroprocessed product of compounds
selected
from the group consisting of:
(i) compounds in the 1.0 ring molecular class,
(ii) compounds in the 1.5 ring molecular class,
- 1 -
CA 02843515 2015-08-21
. .
(iii) compounds defined in (i) or (ii) further comprising one or more alkyl
or
alkenyl substituents on any ring,
(iv) compounds defined in (i), (ii) or (iii) further comprising hetero
atoms
selected from sulfur, nitrogen or oxygen, and
(v) combinations thereof;
wherein the hydroprocessed product has a viscosity? 2.0 cSt at 50 C, and? 1.0
wt. % of
the hydroprocessed product comprises compounds having an atmospheric boiling
point?
565 C.
[0005] In another embodiment, the invention relates to a
hydroprocessed product
produced by the method comprising:
(a) providing a hydrocarbon mixture comprising? 2 wt. % sulfur, and? 0.1
wt.
% of Tar Heavies, the weight percents being based on the weight of the
hydrocarbon
mixture;
(b) combining the hydrocarbon mixture with a utility fluid to produce a
feed
mixture, the utility fluid comprising aromatics and having an ASTM D86 10%
distillation
point? 60 C and a 90% distillation point < 360 C, wherein the feed mixture
comprises 20
wt. % to 95 wt. % of the hydrocarbon mixture and 5 wt. % to 80 wt. % of the
utility fluid
based on the weight of the feed mixture;
(c) contacting the feed mixture with at least one hydroprocessing catalyst
under
catalytic hydroprocessing conditions in the presence of molecular hydrogen to
convert at
least a portion of the feed mixture to a conversion product, the conversion
product
comprising hydroprocessed product; and
(d) separating the hydroprocessed product from the conversion product,
wherein the hydroprocessed product comprises > 10.0 wt. % based on the weight
of the
hydroprocessed product of compounds selected from the group consisting of
(i) compounds of 1.0 ring molecular class,
(ii) compounds of 1.5 ring molecular class,
(iii) compounds defined in (i) or (ii) further comprising one or more alkyl
or
alkenyl substituents on any ring,
- 2 -
CA 02843515 2015-08-21
(iv) compounds defined in (i), (ii) or (iii) further comprising hetero atoms
selected from sulfur, nitrogen or oxygen, and
(v) combinations thereof,
and wherein the hydroprocessed product has a viscosity and sulfur content less
than that of
the hydrocarbon mixture.
100061 In yet another embodiment, the invention relates to a hydroprocessed
product
made by a hydrocarbon conversion method, comprising:
(a) providing a hydrocarbon mixture comprising? 2 wt. % sulfur, and? 0.1
wt.
% of Tar Heavies, the weight percents being based on the weight of the
hydrocarbon
mixture;
(b) combining the hydrocarbon mixture with a utility fluid to produce a
feed
mixture, the utility fluid comprising aromatics and having an ASTM D86 10%
distillation
point? 60 C and a 90% distillation point < 360 C, wherein the feed mixture
comprises 20
wt. % to 95 wt. % of the hydrocarbon mixture and 5 wt. % to 80 wt. % of the
utility fluid
based on the weight of the feed mixture;
(c) contacting the feed mixture with at least one hydroprocessing catalyst
under
catalytic hydroprocessing conditions in the presence of molecular hydrogen to
convert at
least a portion of the feed mixture to a conversion product, the conversion
product
comprising a hydroprocessed product having an atmospheric boiling point > 360
C; and
(d) separating the hydroprocessed product from the conversion product,
wherein the hydroprocessed product comprises > 10.0 wt. % based on the weight
of the
hydroprocessed product of compounds selected from the group consisting of:
(i) compounds in the 1.0 ring molecular class,
(ii) compounds in the 1.5 ring molecular class,
(iii) compounds defined in (i) or (ii) further comprising one or more alkyl
or
alkenyl substituents on any ring,
(iv) compounds defined in (i), (ii) or (iii) further comprising hetero
atoms
selected from sulfur, nitrogen or oxygen, and
(v) combinations thereof,
- 3 -
CA 02843515 2015-08-21
. .
and wherein the hydroprocessed product has a viscosity and sulfur content less
than that of
the hydrocarbon mixture.
[0007] In another embodiment, the invention relates to a
hydroprocessed tar,
comprising: > 10.0 wt. % based on the weight of the hydroprocessed tar of
compounds
selected from the group consisting of:
(i) compounds in the 1.0 ring molecular class,
(ii) compounds in the 1.5 ring molecular class,
(iii) compounds defined in (i) or (ii) further comprising one or more alkyl
or
alkenyl substituents on any ring,
(iv) compounds defined in (i), (ii) or (iii) further comprising hetero
atoms
selected from sulfur, nitrogen or oxygen, and
(v) combinations thereof,
wherein the hydroprocessed tar has a viscosity?: 2.0 cSt at 50 C, and? 1.0 wt.
% of the
hydroprocessed tar comprises compounds having an atmospheric boiling point?
565 C.
Optionally, the hydroprocessed tar comprises? 90.0 wt. % of hydroprocessed SCT
based
on the weight of the hydroprocessed tar. Optionally, the hydroprocessed tar is
utilized to
produce a blend, e.g., a mixture comprising (i) one or more of heavy fuel oil,
vapor-liquid
separator bottoms, fractionator tower bottoms, or SCT and (ii) > 5.0 wt. % of
the
hydroprocessed tar, the weight percents being based on the weight of the
mixture.
[0008] In yet another embodiment, the invention relates to a
hydroprocessed product
made by a hydrocarbon conversion method, comprising:
(a) providing a hydrocarbon mixture comprising? 2 wt. % sulfur, and? 0.1
wt. % of Tar Heavies, the weight percents being based on the weight of the
hydrocarbon
mixture;
(b) combining the hydrocarbon mixture with a utility fluid to produce a
feed
mixture, the utility fluid comprising aromatics and having an ASTM D86 10%
distillation
point? 60 C and a 90% distillation point < 360 C, wherein the feed mixture
comprises 20
wt. % to 95 wt. % of the hydrocarbon mixture and 5 wt. % to 80 wt. % of the
utility fluid
based on the weight of the feed mixture;
- 4 -
CA 02843515 2015-08-21
(c) contacting the feed mixture with at least one hydroprocessing catalyst
under
catalytic hydroprocessing conditions in the presence of molecular hydrogen to
convert at
least a portion of the feed mixture to a conversion product, the conversion
product
comprising a hydroprocessed product having an atmospheric boiling point > 360
C; and
(d) separating the hydroprocessed product from the conversion product,
wherein the hydroprocessed product comprises > 10.0 wt. % based on the weight
of the
hydroprocessed product of compounds selected from the group consisting of:
(i) compounds in the 1.0 ring molecular class,
(ii) compounds in the 1.5 ring molecular class,
(iii) compounds defined in (i) or (ii) further comprising one or more alkyl
or
alkenyl substituents on any ring,
(iv) compounds defined in (i), (ii) or (iii) further comprising hetero
atoms
selected from sulfur, nitrogen or oxygen, and
(v) combinations thereof,
and wherein the hydroprocessed product has a viscosity and sulfur content less
than that of
the hydrocarbon mixture.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Figure 1 shows a 2D GC Chromatogram obtained from a hydroprocessed
product. Figure 2 shows the molecular classes identified in the chromatogram
of Figure 1.
DETAILED DESCRIPTION
[0010] The invention is based in part on the discovery that a
hydroprocessed product
having desirable properties can be made by hydroprocessing tar from pyrolysis
of
hydrocarbons, such as SCT, in the presence of a utility fluid comprising a
significant
amount of single or multi-ring aromatics. Unlike conventional SCT
hydroprocessing, the
process can be operated at temperatures and pressures that favor the desired
hydrocracking
reaction over aromatics hydrogenation. The term "SCT" means (a) a mixture of
hydrocarbons having one or more aromatic core and optionally (b) non-aromatic
and/or
non-hydrocarbon molecules, the mixture being derived from hydrocarbon
pyrolysis and
having a boiling range > about 550 F (290 C) e.g., > 90.0 wt. % of the SCT
molecules
have an atmospheric boiling point? 550 F (290 C). SCT can comprise, e.g., >
50.0 wt. %,
- 5 -
CA 02843515 2015-08-21
e.g., > 75.0 wt. %, such as > 90.0 wt. %, based on the weight of the SCT, of
hydrocarbon
molecules (including mixtures and aggregates thereof) having (i) one or more
aromatic
cores and (ii) a molecular weight?: about C15.
[0011] The hydroprocessed product (and the SCT from which it can be
derived)
comprises to a large extent a mixture of multi-ring compounds. The rings can
be aromatic
or non-aromatic and can contain a variety of substituents and/or heteroatoms.
For example,
the hydroprocessed product can contain, e.g.,? 10.0 wt. %, or? 20.0 wt. %, or
> 30.0 wt.
%, based on the weight of the hydroprocessed product, of aromatic and non-
aromatic multi-
ring compounds. The hydroprocessed product can be made by hydroprocessing a
heavy tar
stream made in one or more hydrocarbon pyrolysis processes such as steam
cracking, the
hydroprocessing being carried out in the presence of the specified utility
fluid. In certain
embodiments, the hydroprocessing produces a highly-aromatic hydrocarbon having
an
atmospheric boiling point in the range of a heavy distillate, VGO, or even
heavier
hydrocarbon. Such products are generally useful as, e.g., a blending component
for fuel
oil.
[0012] In this description and appended claims, a molecule having 0.5 rings
means a
molecule having only one non-aromatic ring and no aromatic rings.
[0013] The term "non-aromatic ring" means four or more carbon atoms joined
in at
least one ring structure wherein at least one of the four or more carbon atoms
in the ring
structure is not an aromatic carbon atom. Aromatic carbon atoms can be
identified using,
e.g., 13C Nuclear magnetic resonance, for example. Non-aromatic rings having
atoms
attached to the ring (e.g., one or more heteroatoms, one or more carbon atoms,
etc.), but
which are not part of the ring structure are within the scope of the term "non-
aromatic
ring".
[0014] Examples of non-aromatic rings include:
a pentacyclic ring ¨ five carbon member ring such as
cyclopentane
- 6 -
CA 02843515 2015-08-21
. .
(ii) a hexcyclic ring ¨ six carbon member ring such as
0
cyclohexane
The non-aromatic ring can be statured as exemplified above or partially
unsaturated
for example, cyclopentene, cyclopenatadiene, cyclohexene and cyclohexadiene.
[0015] Non aromatic rings (which in SCT and the hydroprocessed
product derived
therefrom are primarily six and five member non-aromatic rings), can contain
one or more
heteroatoms such as sulfur (S), nitrogen (N) and oxygen (0). Non limiting
examples of
non-aromatic rings with heteroatoms includes the following
H
S N 0
( ) ( ) c )
tetrahydrothiophene pyrrolidine tetrahydrofuran
H
S
'\...'
tetrahydro-2H-thiopyran piperidine tetrahydro-2H-pyran
The non-aromatic rings with hetero atoms can be statured as exemplified above
or
partially unsaturated.
[0016] In this description and appended claims, a molecule having
1.0 ring means a
molecule having only one aromatic ring or a molecule having only 2 non-
aromatic rings
and no aromatic rings. The term "aromatic ring" means five or six joined in a
ring structure
wherein (i) at least four of the atoms joined in the ring structure are carbon
atoms and (ii)
all of the carbon atoms joined in the ring structure are aromatic carbon
atoms. Aromatic
rings having atoms attached to the ring (e.g., one or more heteroatoms, one or
more carbon
- 7 -
CA 02843515 2015-08-21
atoms, etc.) but which are not part of the ring structure are within the scope
of the term
"non-aromatic ring".
Representative aromatic rings include, e.g.,:
(i) a benzene ring
benzene
(ii) a thiophene ring such as
thiophene
(iii) a pyrrole ring such as
1H-pyrrole
(iv) a furan ring such as
0
furan
[0017] When there is more than one ring in a molecular structure, the rings
can be
aromatic rings and/or non-aromatic rings. The ring to ring connection can be
of two types:
type (1) where at least one side of the ring is shared, and type (2) where the
rings are
connected with at least one bond. The type (1) structure is also known as a
fused ring
structure. The type (2) structure is also commonly known as a bridged ring
structure.
[0018] A few non-limiting examples of the type (1) fused ring structure are
as follows:
- 8 -
CA 02843515 2015-08-21
SO O. 00
naphthalene 1,2,3,4-tetrahydronaphthalene decahydronaphthalene
Sea.
indane octahydropentalene
[0019] A non-limiting example of the type (2) bridged ring structure is as
follows:
(CH2)n ________________________________
where n = 0,1,2, or 3.
[0020] When there are two or more rings (aromatic rings and/or non-aromatic
rings) in
a molecular structure, the ring to ring connection may include all type (1) or
type (2)
connections or a mixture of both types (1) and (2).
[0021] The following define the molecular classes for the multi-ring
compounds for the
purpose of this description and appended claims:
[0022] Compounds of the1.0 ring molecular class contain the following ring
structures
but no other rings:
(i) one aromatic ring 1 = (1.0 ring) in the molecular structure, or
(ii) two non-aromatic rings 2. (0.5 ring) in the molecular structure.
[0023] Compounds of the 1.5 ring molecular class contain the following ring
structures, but no other rings:
(i) one aromatic ring 1. (1.0 ring) and one non-aromatic ring 1- (0.5 ring)
in the
molecular structure or
(ii) three non-aromatic rings 3(0.5 ring) in the molecular structure.
[0024] Compounds of the 2.0 ring molecular class contain the following ring
structures, but no other rings:
(i) two aromatic rings 2 = (1.0 ring) or
- 9 -
CA 02843515 2015-08-21
(ii) one aromatic ring 1. (1.0 ring) and two non-aromatic rings 2. (0.5
ring) in
the molecular structure, or
(iii) four non-aromatic rings 4. (0.5 ring) in the molecular structure.
[0025] Compounds of the 2.5 ring molecular class contain the following ring
structures
but no other rings:
(i) two aromatic rings 2. (1.0 ring) and one non-aromatic rings 1. (0.5
ring) in
the molecular structure or
(ii) one aromatic ring 1. (1.0 ring) and three non-aromatic rings 3. (0.5
ring) in
the molecular structure or
(iii) five non-aromatic rings 5. (0.5 ring) in the molecular structure.
[0026] Likewise compounds of the 3.0, 3.5, 4.0, 4.5, 5.0, etc. molecular
classes contain
a combination of non-aromatic rings counted as 0.5 ring, and aromatic rings
counted as 1.0
ring, such that the total is 3.0, 3.5, 4.0, 4.5, 5.0, etc. respectively.
[0027] All of these multi-ring molecular classes include ring compounds
having
hydrogen, alkyl, or alkenyl groups bound thereto, e.g., one or more of H, CH2,
C2 H4
through Cn H211, CH3, C2 H5 through Cr, H2n+1. Generally, is in the range of
from 1 to 6,
e.g., from 1 to 5.
[0028] One skilled in the art can determine the types and amounts of
compounds in the
multi-ring molecular classes defined above in, e.g., the hydroprocessed
product and the
SCT from which it can be derived. Conventional methods can be utilized to do
this, though
the invention is not limited thereto. For example, it has been found that two-
dimensional
gas chromatography ("2D GC") is a convenient methodology for performing a
quantitative
analysis of samples of tar, hydroprocessed product, and other streams and
mixtures as
might result from operating certain embodiments of the invention. The use of
two-
dimensional chromatography as an analytic tool for identifying the types and
amounts of
compounds of the specified molecular classes will now be described in more
detail. The
invention is not limited to this method, and this description is not meant to
foreclose other
methods for identifying molecular types and amounts within the broader scope
of the
invention, e.g., other gas chromatography/mass spectrometry (GC/MS)
techniques.
- 10-
CA 02843515 2015-08-21
Two-Dimensional Gas Chromatography
[0029] In (2D GC), a sample is subjected to two sequential chromatographic
separations. The first separation is a partial separation by a first or
primary separation
column. The partially separated components are then injected into a second or
secondary
column where they undergo further separation. The two columns usually have
different
selectivities to achieve the desired degree of separation. An example of 2D GC
may be
found in US Patent No. 5,169,039.
[0030] A sample is injected into an inlet device connected to the inlet of
the first
column to produce a first dimension chromatogram. The sample injection method
used is
not critical, and the use of conventional sample injection devices such as a
syringe is
suitable, though the invention is not limited thereto. In certain embodiments,
the inlet
device holds a single sample, although those that hold multiple samples for
injection into
the first column are within the scope of the invention. The column generally
contains a
stationary phase which is usually the column coating material.
[0031] The first column is generally coated with a non-polar material. When
column
coating material is methyl silicon polymer, the polarity can be measured by
the percentage
of methyl groups substituted by the phenyl group. The polarity of a particular
coating
material can be measured on a % of phenyl group substitution scale from 0 to
100 with zero
being non-polar and 80 (80% phenyl substitution) being polar. These methyl
silicon
polymers are considered non-polar and have polarity values in the range 0 to
20. Phenyl-
substituted methyl silicon polymers are considered semi-polar and have polar
values of 21
to 50. Phenyl-substituted methyl silicon polymer coating materials are
considered polar
when greater than 51% phenyl-substituted methyl groups are included in the
polymers.
Other polar coating polymers, such as carbowaxes, are also used in
chromatographic
applications. Carbowaxes are polyethylene glycols of higher molecular weight.
A series of
carborane silicon polymers sold under the trade name Dexsil have also been
designed
especially for high temperature applications.
[0032] The first column, coated with a non-polar material, provides a first
separation of
the sample. The first separation, also known as the first dimension, generates
a series of
bands over a specified time period. This first dimension chromatogram is
similar to a
-11-
CA 02843515 2015-08-21
conventional one-dimensional chromatogram. The bands represent individual
components
or groups of components of the sample injected, and are generally fully
separated or
partially overlapped with adjacent bands.
[0033] When the complex mixture is separated by the first dimension column,
it still
suffers from many co-elutions (components not fully separated by the first
dimension
column). The bands of separated materials from the first dimension are then
completely
sent to the second column to undergo further separation, especially on the co-
eluted
components. The materials are further separated in the second dimension. The
second
dimension is obtained from a second column coated with a semi-polar or polar
material,
preferably a semi-polar coating material.
[0034] To facilitate acquisition of the detector signal, a modulator is
utilized to manage
the flow between the end of the first column and the beginning of the second
column.
Suitable modulators include thermal modulators utilizing trap/release
mechanism, such as
those in which cold nitrogen gas is used to trap separated sample from the
first dimension
followed by a periodic pulse of hot nitrogen to release trapped sample to the
second
dimension. Each pulse is analogous to a sample injection into the second
dimension.
[0035] The role of the modulator is to (1) collect the continuous eluent
flow out from
the end of the first column with a fixed period of time (modulated period) and
(2) inject to
the beginning of the second column by release collected eluent at once at the
end of the
modulated period. The function of the modulator is to (1) define the beginning
time of a
specific second dimensional column separation and (2) define the length of the
second
dimensional separation (modulation period).
[0036] The separated bands from the second dimension are coupled with the
bands
from the first dimension to form a comprehensive 2D chromatogram. The bands
are placed
in a retention plane wherein the first dimension retention times and the
second dimension
retention times form the axes of the 2D chromatogram.
[0037] For example, a conventional GC experiment takes 110 minutes to
separate a
mixture (a chromatogram with 110 minute retention time, x-axis). When the same
experiment is performed under 2D GC conditions with 10 second modulation
period, it will
become 660 chromatograms (60 second x 110 minute divided 10 second) where each
10
- 12 -
CA 02843515 2015-08-21
second chromatogram (y-axis) lines up one-by-one along the retention time axis
(x-axis).
In 2D GC, the x-axis is the first dimension retention time (the same as in
conventional GC),
the y-axis is the second dimensional retention time, and the peak intensity
would project
out in the third dimension z-axis. In order to express this 3D picture in a
two dimensional
diagram, the intensity can be converted based on a pre-defined gray scale
(from black to
white with different shades of grey) or a pre-defined color table to express
their relative
peak intensity.
[0038] Figure 1 shows a 2D GC of a hydroprocessed product sample obtained
by
hydroprocessing SCT in the presence of the specified utility fluid under the
specified
hydroprocessing conditions.
[0039] The 2D GC (GCxGC) system utilizes an Agilent 6890 gas chromatograph
(Agilent Technology, Wilmington, DE) configured with inlet, columns, and
detectors. A
split/splitless inlet system with an eight-vial tray autosampler was used. The
two-
dimensional capillary column system utilizes a non-polar first column (BPX-5,
30 meter,
0.25mm I.D., 1.0 tm film), and a polar (BPX-50, 2 meter, 0.25mm I.D., 0.25 m
film),
second column. Both capillary columns are obtained from SGE Inc. Austin, TX. A
looped
single jet thermal modulation assembly based on ZOEX technology (ZOEX Corp.
Lincoln,
NE) which is a liquid nitrogen cooled "trap-release" dual jet thermal
modulator is installed
between these two columns. A flame ionization detector (FID) is used for the
signal
detection. A 1.0 microliter sample is injected with 25:1 split at 300 C from
Inlet. Carrier
gas flow is substantially constant at 2.0 mL/min. The oven is programmed from
60 C with
0 minute hold and 3.0 C per minute increment to 390 C with 0 minute hold. The
total GC
run time is 110 minutes. The modulation period is 10 seconds. The sampling
rate for the
detector is 100Hz. Figures 1 and 2 show a conventional quantitative analysis
of the 2D GC
data, utilizing a commercial program ("Transform" (Research Systems Inc.
Boulder, CO)
and "PhotoShop" program (Adobe System Inc. San Jose, CA) to generate the
images.
SCT
[0040] It has been observed that SCT comprises a significant amount of Tar
Heavies
("TII"). For the purpose of this description and appended claims, the term
"Tar Heavies"
means a product of hydrocarbon pyrolysis, the TH having an atmospheric boiling
point >
- 13 -
CA 02843515 2015-08-21
565 C and comprising > 5.0 wt. % of molecules having a plurality of aromatic
cores based
on the weight of the product. The TH are typically solid at 25.0 C and
generally include
the fraction of SCT that is not soluble in a 5:1 (vol.:vol.) ratio of n-
pentane: SCT at 25.0 C
("conventional pentane extraction"). The TH can include high-molecular weight
molecules
(e.g., MW > 600) such as asphaltenes and other high-molecular weight
hydrocarbon. The
term "asphaltene or asphaltenes" is defined as heptane insolubles, and is
measured
following ASTM D3279. For example, the TH can comprise > 10.0 wt. % of high
molecular-weight molecules having aromatic cores that are linked together by
one or more
of (i) relatively low molecular-weight alkanes and/or alkenes, e.g., C1 to C3
alkanes and/or
alkenes, (ii) C5 and/or C6 cycloparaffinic rings, or (iii) thiophenic rings.
Generally, > 60.0
wt. % of the TH's carbon atoms are included in one or more aromatic cores
based on the
weight of the TH's carbon atoms, e.g., in the range of 68.0 wt. % to 78.0 wt.
%. While not
wishing to be bound by any theory or model, it is also believed that the TH
form aggregates
having a relatively planar morphology, as a result of Van der Waals attraction
between the
TH molecules. The large size of the TH aggregates, which can be in the range
of, e.g., ten
nanometers to several hundred nanometers ("nm") in their largest dimension,
leads to low
aggregate mobility and diffusivity under catalytic hydroprocessing conditions.
In other
words, conventional TH conversion suffers from severe mass-transport
limitations, which
result in a high selectivity for TH conversion to coke. It has been found that
combining
SCT with the utility fluid breaks down the aggregates into individual
molecules of, e.g., <
5.0 nm in their largest dimension and a molecular weight in the range of about
200 grams
per mole to 2500 grams per mole. This results in greater mobility and
diffusivity of the
SCT's TH, leading to shorter catalyst-contact time and less conversion to coke
under
hydroprocessing condition. As a result, SCT conversion can be run at lower
pressures, e.g.,
500 psig to 1500 psig (34.5 to 103.4 bar guage), leading to a significant
reduction in cost
and complexity over higher-pressure hydroprocessing. The invention is also
advantageous
in that the SCT is not over-cracked so that the amount of light hydrocarbons
produced, e.g.,
C4 or lighter, is less than 5 wt. %, which results in a unique composition of
multi ring
compounds, and further reduces the amount of hydrogen consumed in the
hydroprocessing
step.
- 14 -
CA 02843515 2015-08-21
[0041] SCT starting material differs from other relatively high-molecular
weight
hydrocarbon mixtures, such as crude oil residue ("resid") including both
atmospheric and
vacuum resids and other streams commonly encountered, e.g., in petroleum and
petrochemical processing. The SCT's aromatic carbon content as measured by 13C
NMR is
substantially greater than that of resid. For example, the amount of aromatic
carbon in SCT
typically is greater than 70 wt. % while the amount of aromatic carbon in
resid is generally
less than 40 wt. %. A significant fraction of SCT asphaltenes have an
atmospheric boiling
point that is less than 565 C, for example, only 32.5 wt. % of asphaltenes in
SCT 1 have an
atmospheric boiling point that is greater than 565 C. That is not the case
with vacuum
resid. Even though solvent extraction is an imperfect process, results
indicate that
asphaltenes in vacuum resid are mostly heavy molecules having atmospheric
boiling point
that is greater than 565 C. When subjected to heptane solvent extraction under
substantially the same conditions as those used for vacuum resid, the
asphaltenes obtained
from SCT contains a much greater percentage (on a wt. basis) of molecules
having an
atmospheric boiling point <565 C than is the case for vacuum resid. SCT also
differs from
resid in the relative amount of metals and nitrogen-containing compounds
present. In SCT,
the total amount of metals is < 1000.0 ppmw (parts per million, weight) based
on the
weight of the SCT, e.g., < 100.0 ppmw, such as < 10.0 ppmw. The total amount
of
nitrogen present in SCT is generally less than the amount of nitrogen present
in a crude oil
vacuum resid.
[0042] Selected properties of two representative SCT samples and three
representative
resid samples are set out in the following table.
- 15-
CA 02843515 2015-08-21
Table 1
SCT 1 SCT 2 RESID 1 RESID 2
RESID 3
CARBON (wt. %) 89.9 91.3 86.1 83.33 82.8
HYDROGEN (wt. %) 7.16 6.78 10.7 9.95 9.94
NITROGEN (wt. %) 0.16 0.24 0.48 0.42 0.4
OXYGEN (wt. %) 0.69 N.M. 0.53 0.87
SULFUR (wt. %) 2.18 0.38 2.15 5.84 6.1
Kinematic Viscosity at 50 C (cSt) 988 7992 > 1,000 > 1,000 >
1,000
Weight % having an atmospheric boiling
point? 565 C 16.5 20.2
Asphaltenes 22.6 31.9 91 85.5 80
NICKEL wppm <0.7 N.M.* 52.5 48.5 60.1
VANADIUM wppm 0.22 N.M. 80.9 168 149
IRON wppm 4.23 N.M. 54.4 11 4
Aromatic Carbon (wt. %) 71.9 75.6 27.78 32.32
32.65
Aliphatic Carbon (wt. %) 28.1 24.4 72.22 67.68
67.35
Methyls (wt. %) 11 7.5 9.77 13.35
11.73
% C in long chains (wt. %) 0.7 0.63 11.3 15.28
10.17
Aromatic H (wt. %) 38.1 43.5 N.M. N.M. 6.81
% Sat H (wt. %) 60.8 55.1 N.M. N.M. 93.19
Olefins (wt. %) 1.1 1.4 N.M. N.M. 0
*N.M. = Not Measured
The amount of aliphatic carbon and the amount of carbon in long chains is
substantially
lower in SCT compared to resid. Although the SCT's total carbon is only
slightly higher
and the oxygen content (wt. basis) is similar to that of resid, the SCT's
metals, hydrogen,
and nitrogen (wt. basis) range is considerably lower. The SCT's kinematic
viscosity at
50 C is generally? 100 cSt, or? 1000 cSt even though the relative amount of
SCT having
an atmospheric boiling point? 565 C is much less than is the case for resid.
[0043] SCT is generally obtained as a product of hydrocarbon pyrolysis. The
pyrolysis
process can include, e.g., thermal pyrolysis, such as thermal pyrolysis
processes utilizing
water. One such pyrolysis process, steam cracking, is described in more detail
below. The
invention is not limited to steam cracking, and this description is not meant
to foreclose the
use of other pyrolysis processes within the broader scope of the invention.
- 16-
CA 02843515 2015-08-21
. .
Obtaining SCT by Pyrolysis
[00441 Conventional steam cracking utilizes a pyrolysis furnace
which has two main
sections: a convection section and a radiant section. The feedstock (first
mixture) typically
enters the convection section of the furnace where the first mixture's
hydrocarbon
component is heated and vaporized by indirect contact with hot flue gas from
the radiant
section and by direct contact with the first mixture's steam component. The
steam-
vaporized hydrocarbon mixture is then introduced into the radiant section
where the bulk
cracking takes place. A second mixture is conducted away from the pyrolysis
furnace, the
second mixture comprising products resulting from the pyrolysis of the first
mixture and
any unreacted components of the first mixture. At least one separation stage
is generally
located downstream of the pyrolysis furnace, the separation stage being
utilized for
separating from the second mixture one or more of light olefin, SCN, SCGO,
SCT, water,
unreacted hydrocarbon components of the first mixture, etc. The separation
stage can
comprise, e.g., a primary fractionator. Generally, a cooling stage, typically
either direct
quench or indirect heat exchange is located between the pyrolysis furnace and
the
separation stage.
100451 In one or more embodiments, SCT is obtained as a product of
pyrolysis
conducted in one or more pyrolysis furnaces, e.g., one or more steam cracking
furnaces.
Besides SCT, such furnaces generally produce (i) vapor-phase products such as
one or
more of acetylene, ethylene, propylene, butenes, and (ii) liquid-phase
products comprising,
e.g., one or more of C5+ molecules and mixtures thereof The liquid-phase
products are
generally conducted together to a separation stage, e.g., a primary
fractionator, for
separations of one or more of (a) overheads comprising steam-cracked naphtha
("SCN",
e.g., C5 - C10 species) and steam cracked gas oil ("SCGO"), the SCGO
comprising > 90.0
wt. % based on the weight of the SCGO of molecules (e.g., C10 ¨ C17 species)
having an
atmospheric boiling point in the range of about 400 F to 550 F (200 C to 290
C), and (b)
bottoms comprising > 90.0 wt. % SCT, based on the weight of the bottoms, the
SCT having
a boiling range > about 550 F (290 C) and comprising molecules and mixtures
thereof
having a molecular weight? about C15.
- 17-
CA 02843515 2015-08-21
[0046] The feed to the pyrolysis furnace is a first mixture, the first
mixture comprising
> 10.0 wt. % hydrocarbon based on the weight of the first mixture, e.g., >
25.0 wt. %,?
50.0 wt. %, such as? 65 wt. %. Although the hydrocarbon can comprise, e.g.,
one or more
of light hydrocarbons such as methane, ethane, propane, butane etc., it can be
particularly
advantageous to utilize the invention in connection with a first mixture
comprising a
significant amount of higher molecular weight hydrocarbons because the
pyrolysis of these
molecules generally results in more SCT than does the pyrolysis of lower
molecular weight
hydrocarbons. As an example, it can be advantageous for the total of the first
mixtures fed
to a multiplicity of pyrolysis furnaces to comprise? 1.0 wt. % or? 25.0 wt. %
based on the
weight of the first mixture of hydrocarbons that are in the liquid phase at
ambient
temperature and atmospheric pressure.
[0047] The first mixture can further comprise diluent, e.g., one or more of
nitrogen,
water, etc., e.g., > 1.0 wt. % diluent based on the weight of the first
mixture, such as
> 25.0 wt. %. When the pyrolysis is steam cracking, the first mixture can be
produced by
combining the hydrocarbon with a diluent comprising steam, e.g., at a ratio of
0.1 to 1.0 kg
steam per kg hydrocarbon, or a ratio of 0.2 to 0.6 kg steam per kg
hydrocarbon.
[0048] In one or more embodiments, the first mixture's hydrocarbon
component
comprises? 10.0 wt. %, e.g.,? 50.0 wt. %, such as? 90.0 wt. % (based on the
weight of
the hydrocarbon component) of one or more of naphtha, gas oil, vacuum gas oil,
crude oil,
resid, or resid admixtures; including those comprising > about 0.1 wt. %
asphaltenes.
Suitable crude oils include, e.g., high-sulfur virgin crude oils, such as
those rich in
polycyclic aromatics. Optionally, the first mixture's hydrocarbon component
comprises
sulfur, e.g., > 0.1 wt. % sulfur based on the weight of the first mixture's
hydrocarbon
component, e.g.,? 1.0 wt. %, such as in the range of about 1.0 wt. % to about
5.0 wt. %.
Optionally, at least a portion of the first mixture's sulfur-containing
molecules, e.g.,? 10.0
wt. % of the first mixture's sulfur-containing molecules, contain at least one
aromatic ring
("aromatic sulfur"). When (i) the first mixture's hydrocarbon is a crude oil
or crude oil
fraction comprising? 0.1 wt. % of aromatic sulfur and (ii) the pyrolysis is
steam cracking,
then the, SCT contains a significant amount of sulfur derived from the first
mixture's
- 18-
CA 02843515 2015-08-21
aromatic sulfur. For example, the SCT sulfur content can be about 3 to 4 times
higher in
the SCT than in the first mixture's hydrocarbon component, on a weight basis.
[0049] In a particular embodiment, the first mixture's hydrocarbon
comprises one or
more crude oils and/or one or more crude oil fractions, such as those obtained
from an
atmospheric pipestill ("APS") and/or vacuum pipestill ("VPS"). The crude oil
and/or
fraction thereof is optionally desalted prior to being included in the first
mixture. An
example of a crude oil fraction utilized in the first mixture is produced by
combining
separating APS bottoms from a crude oil and followed by VPS treatment of the
APS
bottoms.
[0050] Optionally, the pyrolysis furnace has at least one vapor/liquid
separation device
(sometimes referred to as flash pot or flash drum) integrated therewith, for
upgrading the
first mixture. Such vapor/liquid separator devices are particularly suitable
when the first
mixture's hydrocarbon component comprises > about 0.1 wt. % asphaltenes based
on the
weight of the first mixture's hydrocarbon component, e.g., > about 5.0 wt. %.
Conventional vapor/liquid separation devices can be utilized to do this,
though the
invention is not limited thereto. Examples of such conventional vapor/liquid
separation
devices include those disclosed in U.S. Patent Nos. 7,138,047; 7,090,765;
7,097,758;
7,820,035; 7,311,746; 7,220,887; 7,244,871; 7,247,765; 7,351,872; 7,297,833;
7,488,459;
7,312,371; and 7,235,705. Suitable vapor/liquid separation devices are also
disclosed in
U.S. Patent Nos. 6,632,351 and 7,578,929. Generally, when using a vapor/liquid
separation device, the composition of the vapor phase leaving the device is
substantially the
same as the composition of the vapor phase entering the device, and likewise
the
composition of the liquid phase leaving the flash drum is substantially the
same as the
composition of the liquid phase entering the device, i.e., the separation in
the vapor/liquid
separation device consists essentially of a physical separation of the two
phases entering
the drum.
[0051] In embodiments using a vapor/liquid separation device integrated
with the
pyrolysis furnace, at least a portion of the first mixture's hydrocarbon
component is
provided to the inlet of a convection section of a pyrolysis unit, wherein
hydrocarbon is
heated so that at least a portion of the hydrocarbon is in the vapor phase.
When a diluent
- 19 -
CA 02843515 2015-08-21
(e.g., steam) is utilized, the first mixture's diluent component is optionally
(but preferably)
added in this section and mixed with the hydrocarbon component to produce the
first
mixture. The first mixture, at least a portion of which is in the vapor phase,
is then flashed
in at least one vapor/liquid separation device in order to separate and
conduct away from
the first mixture at least a portion of the first mixture's high molecular-
weight molecules,
such as asphaltenes. A bottoms fraction can be conducted away from the vapor-
liquid
separation device, the bottoms fraction comprising, e.g., > 10.0 % (on a wt.
basis) of the
first mixture's asphaltenes. When the pyrolysis is steam cracking and the
first mixture's
hydrocarbon component comprises one or more crude oil or fractions thereof,
the steam
cracking furnace can be integrated with a vapor/liquid separation device
operating at a
temperature in the range of from about 600 F to about 950 F and a pressure in
the range of
about 275 kPa to about 1400 kPa, e.g., a temperature in the range of from
about 430 C to
about 480 C and a pressure in the range of about 700 kPa to 760 kPa. The
overheads from
the vapor/liquid separation device can be subjected to further heating in the
convection
section, and are then introduced via crossover piping into the radiant section
where the
overheads are exposed to a temperature > 760 C at a pressure > 0.5 bar (gauge)
e.g., a
temperature in the range of about 790 C to about 850 C and a pressure in the
range of
about 0.6 bar (gauge) to about 2.0 bar (gauge), to carry out the pyrolysis
(e.g., cracking
and/or reforming) of the first mixture's hydrocarbon component.
[0052] One of
the advantages of having a vapor/liquid separation device located
downstream of the convection section inlet and upstream of the crossover
piping to the
radiant section is that it increases the range of hydrocarbon types available
to be used
directly, without pretreatment, as hydrocarbon components in the first
mixture. For
example, the first mixture's hydrocarbon component can comprise > 50.0 wt. %,
e.g., >
75.0 wt. %, such as > 90.0 wt. % (based on the weight of the first mixture's
hydrocarbon
component) of one or more crude oils, even high naphthenic acid-containing
crude oils and
fractions thereof. Feeds having a high naphthenic acid content are among those
that
produce a high quantity of tar and are especially suitable when at least one
vapor/liquid
separation device is integrated with the pyrolysis furnace. If desired, the
first mixture's
composition can vary over time, e.g., by utilizing a first mixture having a
first hydrocarbon
- 20 -
CA 02843515 2015-08-21
component during a first time period and then utilizing a first mixture having
a second
hydrocarbon component during a second time period, the first and second
hydrocarbons
being substantially different hydrocarbons or substantially different
hydrocarbon mixtures.
The first and second periods can be of substantially equal duration, but this
is not required.
Alternating first and second periods can be conducted in sequence continuously
or semi-
continuously (e.g., in "blocked" operation) if desired. This embodiment can be
utilized for
the sequential pyrolysis of incompatible first and second hydrocarbon
components (i.e.,
where the first and second hydrocarbon components are mixtures that are not
sufficiently
compatible to be blended under ambient conditions). For example, a first
hydrocarbon
component comprising a virgin crude oil can be utilized to produce the first
mixture during
a first time period and steam cracked tar utilized to produce the first
mixture during a
second time period.
[0053] In other embodiments, the vapor/liquid separation device is not
used. For
example when the first mixture's hydrocarbon comprises crude oil and/or one or
more
fractions thereof, the pyrolysis conditions can be conventional steam cracking
conditions.
Suitable steam cracking conditions include, e.g., exposing the first mixture
to a temperature
(measured at the radiant outlet) > 400 C, e.g., in the range of 400 C to 900
C, and a
pressure > 0.1 bar, for a cracking residence time period in the range of from
about 0.01
second to 5.0 second. In one or more embodiments, the first mixture comprises
hydrocarbon and diluent, wherein the first mixture's hydrocarbon comprises >
50.0 wt. %
based on the weight of the first mixture's hydrocarbon of one or more of waxy
residues,
atmospheric residues, naphtha, residue admixtures, or crude oil. The diluent
comprises,
e.g., > 95.0 wt. % water based on the weight of the diluent. When the first
mixture
comprises 10.0 wt. % to 90.0 wt. % diluent based on the weight of the first
mixture, the
pyrolysis conditions generally include one or more of (i) a temperature in the
range of
760 C to 880 C; (ii) a pressure in the range of from 1.0 to 5.0 bar
(absolute), or (iii) a
cracking residence time in the range of from 0.10 to 2.0 seconds.
[0054] A second mixture is conducted away from the pyrolysis furnace, the
second
mixture being derived from the first mixture by the pyrolysis. When the
specified pyrolysis
conditions are utilized, the second mixture generally comprises > 1.0 wt. % of
C2
-21 -
CA 02843515 2015-08-21
unsaturates and? 0.1 wt. % of TH, the weight percents being based on the
weight of the
second mixture. Optionally, the second mixture comprises? 5.0 wt. % of C2
unsaturates
and/or? 0.5 wt. % of TH, such as > 1.0 wt. % TH. Although the second mixture
generally
contains a mixture of the desired light olefins, SCN, SCGO, SCT, and unreacted
components of the first mixture (e.g., water in the case of steam cracking,
but also in some
cases unreacted hydrocarbon), the relative amount of each of these generally
depends on,
e.g., the first mixture's composition, pyrolysis furnace configuration,
process conditions
during the pyrolysis, etc. The second mixture is generally conducted away for
the
pyrolysis section, e.g., for cooling and separation stages.
[0055] In one or more embodiments, the second mixture's TH comprise? 10.0
wt. %
of TH aggregates having an average size in the range of 10.0 nm to 300.0 nm in
at least one
dimension and an average number of carbon atoms? 50, the weight percent being
based on
the weight of Tar Heavies in the second mixture. Generally, the aggregates
comprise >
50.0 wt. %, e.g.,? 80.0 wt. %, such as? 90.0 wt. % of TH molecules having a
C:H atomic
ratio in the range of from 1.0 to 1.8, a molecular weight in the range of 250
to 5000, and a
melting point in the range of 100 C to 700 C.
[0056] Although it is not required, the invention is compatible with
cooling the second
mixture downstream of the pyrolysis furnace, e.g., the second mixture can be
cooled using
a system comprising transfer line heat exchangers. For example, the transfer
line heat
exchangers can cool the process stream to a temperature in the range of about
700 C to
350 C, in order to efficiently generate super-high pressure steam which can be
utilized by
the process or conducted away. If desired, the second mixture can be subjected
to direct
quench at a point typically between the furnace outlet and the separation
stage. The quench
can be accomplished by contacting the second mixture with a liquid quench
stream, in lieu
of, or in addition to the treatment with transfer line exchangers. Where
employed in
conjunction with at least one transfer line exchanger, the quench liquid is
preferably
introduced at a point downstream of the transfer line exchanger(s). Suitable
quench liquids
include liquid quench oil, such as those obtained by a downstream quench oil
knock-out
drum, pyrolysis fuel oil and water, which can be obtained from conventional
sources, e.g.,
condensed dilution steam.
- 22 -
CA 02843515 2015-08-21
[0057] A separation stage is generally utilized downstream of the pyrolysis
furnace and
downstream of the transfer line exchanger and/or quench point for separating
from the
second mixture one or more of light olefin, SCN, SCGO, SCT, or water.
Conventional
separation equipment can be utilized in the separation stage, e.g., one or
more flash drums,
fractionators, water-quench towers, indirect condensers, etc., such as those
described in
U.S. Patent No. 8,083,931. In the separation stage, a third mixture, tar
stream can be
separated from the second mixture, with the third mixture comprising > 10.0
wt. % of the
second mixture's TH based on the weight of the second mixture's TH. When the
pyrolysis
is steam cracking, the third mixture generally comprises SCT, which is
obtained, e.g., from
an SCGO stream and/or a bottoms stream of the steam cracker's primary
fractionator, from
flash-drum bottoms (e.g., the bottoms of one or more flash drums located
downstream of
the pyrolysis furnace and upstream of the primary fractionator), or a
combination thereof
[0058] In one or more embodiments, the third mixture comprises > 50.0 wt. %
of the
second mixture's TH based on the weight of the second mixture's TH. For
example, the
third mixture can comprise > 90.0 wt. % of the second mixture's TH based on
the weight of
the second mixture's TH. The third mixture can have, e.g., (i) a sulfur
content in the range
of 0.5 wt %. to 7.0 wt. %, (ii) a TH content in the range of from 5.0 wt. % to
40.0 wt. %,
the weight percents being based on the weight of the third mixture, (iii) a
density at 15 C in
the range of 0.98 g/cm3 to 1.15 g/cm3, e.g., in the range of 1.07 g/cm3 to
1.15 g/cm3, and
(iv) a 50 C viscosity in the range of 200 cSt to 1.0 x 107 cSt.
[0059] The third mixture can comprise TH aggregates. In one or more
embodiments,
the third mixture comprises > 50.0 wt. % of the second mixture's TH aggregates
based on
the weight of the second mixture's TH aggregates. For example, the third
mixture can
comprise > 90.0 wt. % of the second mixture's TH aggregates based on the
weight of the
second mixture's TH aggregates.
[0060] The third mixture is generally conducted away from the separation
stage for
hydroprocessing of the third mixture in the presence of a utility fluid.
Examples of utility
fluids useful in the invention will now be described in more detail. The
invention is not
limited to the use of these utility fluids, and this description is not meant
to foreclose other
utility fluids within the broader scope of the invention.
-23 -
CA 02843515 2015-08-21
. .
Utility Fluid
[0061]
The utility fluid comprises aromatics (i.e., comprises molecules having at
least
one aromatic core) and has an ASTM D86 10% distillation point > 60 C and a 90%
distillation point < 360 C. Optionally, the utility fluid (which can be a
solvent or mixture
of solvents) has an ASTM D86 10% distillation point? 120 C, e.g., > 140 C,
such as >
150 C and/or an ASTM D86 90% distillation point < 300 C.
[0062]
In one or more embodiments, the utility fluid (i) has a critical
temperature in the
range of 285 C to 400 C and (ii) comprises? 80.0 wt. % of 1-ring aromatics
and/or 2-ring
aromatics, including alkyl-functionalized derivatives thereof, based on the
weight of the
utility fluid.
For example, the utility fluid can comprise, e.g., > 90.0 wt. % of a single-
ring aromatic, including those having one or more hydrocarbon substituents,
such as from 1
to 3 or 1 to 2 hydrocarbon substituents. Such substituents can be any
hydrocarbon group
that is consistent with the overall solvent distillation characteristics.
Examples of such
hydrocarbon groups include, but are not limited to, those selected from the
group consisting
of C1-C6 alkyl, wherein the hydrocarbon groups can be branched or linear and
the
hydrocarbon groups can be the same or different. Optionally, the utility fluid
comprises?
90.0 wt. % based on the weight of the utility fluid of one or more of benzene,
ethylbenzene,
trimethylbenzene, xylenes, toluene, naphthalenes, alkylnaphthalenes (e.g.,
methylnaphtalenes), tetralins, or alkyltetralins (e.g., methyltetralins).
It is generally
desirable for the utility fluid to be substantially free of molecules having
alkenyl
functionality, particularly in embodiments utilizing a hydroprocessing
catalyst having a
tendency for coke formation in the presence of such molecules. In an
embodiment, the
utility fluid comprises < 10.0 wt. % of ring compounds having C1-C6 sidechains
with
alkenyl functionality, based on the weight of the utility fluid.
[0063]
In certain embodiments, the utility fluid comprises SCN and/or SCGO, e.g.,
SCN and/or SCGO separated from the second mixture in a primary fractionator
downstream of a pyrolysis furnace operating under steam cracking conditions.
Optionally,
the SCN or SCGO can be hydrotreated in different conventional hydrotreaters
(e.g. not
hydrotreated with the tar). The utility fluid can comprise, e.g., > 50.0 wt. %
of the
separated gas oil, based on the weight of the utility fluid. In certain
embodiments, at least a
- 24 -
CA 02843515 2015-08-21
portion of the utility fluid is obtained from the hydroprocessed product,
e.g., by separating
and re-cycling a portion of the hydroprocessed product having an atmospheric
boiling point
< 300 C.
[0064]
Generally, the utility fluid contains sufficient amount of molecules having
one
or more aromatic cores to effectively increase run length during
hydroprocessing of the
third mixture. For example, the utility fluid can comprise > 50.0 wt. % of
molecules
having at least one aromatic core, e.g., > 60.0 wt. %, such as > 70 wt. %,
based on the total
weight of the utility fluid. In an embodiment, the utility fluid comprises (i)
> 60.0 wt. % of
molecules having at least one aromatic core and (ii) < 1.0 wt. % of ring
compounds with
C1-C6 sidechains having alkenyl functionality, the weight percents being based
on the
weight of the utility fluid.
The utility fluid is utilized in hydroprocessing the third mixture, e.g., for
effectively
increasing run-length during hydroprocessing. The relative amounts of utility
fluid and
third mixture during hydroprocessing are generally in the range of from about
20.0 wt. % to
about 95.0 wt. % of the third mixture and from about 5.0 wt. % to about 80.0
wt. % of the
utility fluid, based on total weight of utility fluid plus third mixture. For
example, the
relative amounts of utility fluid and third mixture during hydroprocessing can
be in the
range of (i) about 20.0 wt. % to about 90.0 wt. % of the third mixture and
about 10.0 wt. %
to about 80.0 wt. % of the utility fluid, or (ii) from about 40.0 wt. % to
about 90.0 wt. % of
the third mixture and from about 10.0 wt. % to about 60.0 wt. % of the utility
fluid. At
least a portion of the utility fluid can be combined with at least a portion
of the third
mixture within the hydroprocessing vessel or hydroprocessing zone, but this is
not
required, and in one or more embodiments at least a portion of the utility
fluid and at least a
portion of the third mixture are supplied as separate streams and combined
into one feed
stream prior to entering (e.g., upstream of) the hydroprocessing stage(s). For
example, the
third mixture and utility fluid can be combined to produce a feedstock
upstream of the
hydroprocessing stage, the feedstock comprising, e.g., (i) about 20.0 wt. % to
about 90.0
wt. % of the third mixture and about 10.0 wt. % to about 80.0 wt. % of the
utility fluid, or
(ii) from about 40.0 wt. % to about 90.0 wt. % of the third mixture and from
about 10.0 wt.
% to about 60.0 wt. % of the utility fluid, the weight percents being based on
the weight of
- 25 -
CA 02843515 2015-08-21
the feedstock. The feedstock can be conducted to the hydroprocessing stage for
the
hydroprocessing.
Hydroprocessing
[0065] Hydroprocessing of the third mixture in the presence of the utility
fluid can
occur in one or more hydroprocessing stages, the stages comprising one or more
hydroprocessing vessels or zones. Vessels and/or zones within the
hydroprocessing stage
in which catalytic hydroprocessing activity occurs generally include at least
one
hydroprocessing catalyst. The catalysts can be mixed or stacked, such as when
the catalyst
is in the form of one or more fixed beds in a vessel or hydroprocessing zone.
[0066] Conventional hydroprocessing catalyst can be utilized for
hydroprocessing the
third mixture in the presence of the utility fluid, such as those specified
for use in resid
and/or heavy oil hydroprocessing, but the invention is not limited thereto.
Suitable
hydroprocessing catalysts include those comprising (i) one or more bulk metals
and/or (ii)
one or more metals on a support. The metals can be in elemental form or in the
form of a
compound. In one or more embodiments, the hydroprocessing catalyst includes at
least one
metal from any of Groups 5 to 10 of the Periodic Table of the Elements
(tabulated as the
Periodic Chart of the Elements, The Merck Index, Merck & Co., Inc., 1996).
Examples of
such catalytic metals include, but are not limited to, vanadium, chromium,
molybdenum,
tungsten, manganese, technetium, rhenium, iron, cobalt, nickel, ruthenium,
palladium,
rhodium, osmium, iridium, platinum, or mixtures thereof.
[0067] In one or more embodiments, the catalyst has a total amount of
Groups 5 to 10
metals per gram of catalyst of at least 0.0001 grams, or at least 0.001 grams
or at least 0.01
grams, in which grams are calculated on an elemental basis. For example, the
catalyst can
comprise a total amount of Group 5 to 10 metals in a range of from 0.0001
grams to 0.6
grams, or from 0.001 grams to 0.3 grams, or from 0.005 grams to 0.1 grams, or
from 0.01
grams to 0.08 grams. In a particular embodiment, the catalyst further
comprises at least
one Group 15 element. An example of a preferred Group 15 element is
phosphorus. When
a Group 15 element is utilized, the catalyst can include a total amount of
elements of Group
15 in a range of from 0.000001 grams to 0.1 grams, or from 0.00001 grams to
0.06 grams,
- 26 -
CA 02843515 2015-08-21
or from 0.00005 grams to 0.03 grams, or from 0.0001 grams to 0.001 grams, in
which
grams are calculated on an elemental basis.
[0068] In an embodiment, the catalyst comprises at least one Group 6 metal.
Examples
of preferred Group 6 metals include chromium, molybdenum and tungsten. The
catalyst
may contain, per gram of catalyst, a total amount of Group 6 metals of at
least 0.00001
grams, or at least 0.01 grams, or at least 0.02 grams, in which grams are
calculated on an
elemental basis. For example the catalyst can contain a total amount of Group
6 metals per
gram of catalyst in the range of from 0.0001 grams to 0.6 grams, or from 0.001
grams to
0.3 grams, or from 0.005 grams to 0.1 grams, or from 0.01 grams to 0.08 grams,
the
number of grams being calculated on an elemental basis.
100691 In related embodiments, the catalyst includes at least one Group 6
metal and
further includes at least one metal from Group 5, Group 7, Group 8, Group 9,
or Group 10.
Such catalysts can contain, e.g., the combination of metals at a molar ratio
of Group 6
metal to Group 5 metal in a range of from 0.1 to 20, 1 to 10, or 2 to 5, in
which the ratio is
on an elemental basis. Alternatively, the catalyst will contain the
combination of metals at
a molar ratio of Group 6 metal to a total amount of Groups 7 to 10 metals in a
range of
from 0.1 to 20, 1 to 10, or 2 to 5, in which the ratio is on an elemental
basis.
[0070] When the catalyst includes at least one Group 6 metal and one or
more metals
from Groups 9 or 10, e.g., molybdenum-cobalt and/or tungsten-nickel, these
metals can be
present, e.g., at a molar ratio of Group 6 metal to Groups 9 and 10 metals in
a range of from
1 to 10, or from 2 to 5, in which the ratio is on an elemental basis. When the
catalyst
includes at least one of Group 5 metal and at least one Group 10 metal, these
metals can be
present, e.g., at a molar ratio of Group 5 metal to Group 10 metal in a range
of from 1 to
10, or from 2 to 5, where the ratio is on an elemental basis. Catalysts which
further
comprise inorganic oxides, e.g., as a binder and/or support, are within the
scope of the
invention. For example, the catalyst can comprise (i) > 1.0 wt. % of one or
more metals
selected from Groups 6, 8, 9, and 10 of the Periodic Table and (ii) > 1.0 wt.
% of an
inorganic oxide, the weight percents being based on the weight of the
catalyst.
[0071] The invention encompasses incorporating into (or depositing on) a
support one
or catalytic metals e.g., one or more metals of Groups 5 to 10 and/or Group
15, to form the
-27 -
CA 02843515 2015-08-21
hydroprocessing catalyst. The support can be a porous material. For example,
the support
can comprise one or more refractory oxides, porous carbon-based materials,
zeolites, or
combinations thereof suitable refractory oxides include, e.g., alumina,
silica, silica-alumina,
titanium oxide, zirconium oxide, magnesium oxide, and mixtures thereof.
Suitable porous
carbon-based materials include, activated carbon and/or porous graphite.
Examples of
zeolites include, e.g., Y-zeolites, beta zeolites, mordenite zeolites, ZSM-5
zeolites, and
ferrierite zeolites. Additional examples of support materials include gamma
alumina, theta
alumina, delta alumina, alpha alumina, or combinations thereof The amount of
gamma
alumina, delta alumina, alpha alumina, or combinations thereof, per gram of
catalyst
support, can be in a range of from 0.0001 grams to 0.99 grams, or from 0.001
grams to 0.5
grams, or from 0.01 grams to 0.1 grams, or at most 0.1 grams, as determined by
x-ray
diffraction. In a particular embodiment, the hydroprocessing catalyst is a
supported
catalyst, the support comprising at least one alumina, e.g., theta alumina, in
an amount in
the range of from 0.1 grams to 0.99 grams, or from 0.5 grams to 0.9 grams, or
from 0.6
grams to 0.8 grams, the amounts being per gram of the support. The amount of
alumina
can be determined using, e.g., x-ray diffraction. In alternative embodiments,
the support
can comprise at least 0.1 grams, or at least 0.3 grams, or at least 0.5 grams,
or at least 0.8
grams of theta alumina.
[0072] When a
support is utilized, the support can be impregnated with the desired
metals to form the hydroprocessing catalyst. The support can be heat-treated
at
temperatures in a range of from 400 C to 1200 C, or from 450 C to 1000 C, or
from
600 C to 900 C, prior to impregnation with the metals. In certain embodiments,
the
hydroprocessing catalyst can be formed by adding or incorporating the Groups 5
to 10
metals to shaped heat-treated mixtures of support. This type of formation is
generally
referred to as overlaying the metals on top of the support material.
Optionally, the catalyst
is heat treated after combining the support with one or more of the catalytic
metals, e.g., at
a temperature in the range of from 150 C to 750 C, or from 200 C to 740 C, or
from
400 C to 730 C. Optionally, the catalyst is heat treated in the presence of
hot air and/or
oxygen-rich air at a temperature in a range between 400 C and 1000 C to remove
volatile
matter such that at least a portion of the Groups 5 to 10 metals are converted
to their
- 28 -
CA 02843515 2015-08-21
corresponding metal oxide. In other embodiments, the catalyst can be heat
treated in the
presence of oxygen (e.g., air) at temperatures in a range of from 35 C to 500
C, or from
100 C to 400 C, or from 150 C to 300 C. Heat treatment can take place for a
period of
time in a range of from 1 to 3 hours to remove a majority of volatile
components without
converting the Groups 5 to 10 metals to their metal oxide form. Catalysts
prepared by such
a method are generally referred to as "uncalcined" catalysts or "dried." Such
catalysts can
be prepared in combination with a sulfiding method, with the Groups 5 to 10
metals being
substantially dispersed in the support. When the catalyst comprises a theta
alumina support
and one or more Groups 5 to 10 metals, the catalyst is generally heat treated
at a
temperature? 400 C to form the hydroprocessing catalyst. Typically, such heat
treating is
conducted at temperatures < 1200 C.
[0073] The catalyst can be in shaped forms, e.g., one or more of discs,
pellets,
extrudates, etc., though this is not required. Non-limiting examples of such
shaped forms
include those having a cylindrical symmetry with a diameter in the range of
from about
0.79 mm to about 3.2 mm (1/32tid to 118th inch), from about 1.3 mm to about
2.5 mm (1/20th
to 1/10th inch), or from about 1.3 mm to about 1.6 mm (1/20th to 1/16th inch).
Similarly-
sized non-cylindrical shapes are within the scope of the invention, e.g.,
trilobe, quadralobe,
etc. Optionally, the catalyst has a flat plate crush strength in a range of
from 50-500 N/cm,
or 60-400 N/cm, or 100-350 N/cm, or 200-300 N/cm, or 220-280 N/cm.
[0074] Porous catalysts, including those having conventional pore
characteristics, are
within the scope of the invention. When a porous catalyst is utilized, the
catalyst can have
a pore structure, pore size, pore volume, pore shape, pore surface area, etc.,
in ranges that
are characteristic of conventional hydroprocessing catalysts, though the
invention is not
limited thereto. For example, the catalyst can have a median pore size that is
effective for
hydroprocessing SCT molecules, such catalysts having a median pore size in the
range of
from 30 A to 1000 A, or 50 A to 500 A, or 60 A to 300 A. Pore size can be
determined
according to ASTM Method D4284-07 Mercury Porosimetry.
[0075] In a particular embodiment, the hydroprocessing catalyst has a
median pore
diameter in a range of from 50 A to 200 A. Alternatively, the hydroprocessing
catalyst has
a median pore diameter in a range of from 90 A to 180 A, or 100 A to 140 A, or
110 A to
- 29 -
CA 02843515 2015-08-21
130 A. In another embodiment, the hydroprocessing catalyst has a median pore
diameter
ranging from 50 A to 150 A. Alternatively, the hydroprocessing catalyst has a
median pore
diameter in a range of from 60 A to 135 A, or from 70 A to 120 A. In yet
another
alternative, hydroprocessing catalysts having a larger median pore diameter
are utilized,
e.g., those having a median pore diameter in a range of from 180 A to 500 A,
or 200 A to
300 A, or 230A to 250 A.
[0076] Generally, the hydroprocessing catalyst has a pore size distribution
that is not so
great as to significantly degrade catalyst activity or selectivity. For
example, the
hydroprocessing catalyst can have a pore size distribution in which at least
60% of the
pores have a pore diameter within 45 A, 35 A, or 25 A of the median pore
diameter. In
certain embodiments, the catalyst has a median pore diameter in a range of
from 50 A to
180 A, or from 60 A to 150 A, with at least 60% of the pores having a pore
diameter within
45 A, 35 A, or 25 A of the median pore diameter.
[0077] When a porous catalyst is utilized, the catalyst can have, e.g., a
pore volume?
0.3 cm3/g, such? 0.7 cm3/g, or? 0.9 cm3/g. In certain embodiments, pore volume
can
range, e.g., from 0.3 cm3/g to 0.99 cm3/g, 0.4 cm3/g to 0.8 cm3/g, or 0.5
cm3/g to 0.7 cm3/g.
[0078] In certain embodiments, a relatively large surface area can be
desirable. As an
example, the hydroprocessing catalyst can have a surface area? 60 m2/g, or?
100 m2/g, or
> 120 m2/g, or >170 m2/g, or? 220 m2/g, or? 270 m2/g; such as in the range of
from 100
m2/g to 300 m2/g, or 120 m2/g to 270 m2/g, or 130 m2/g to 250 m2/g, or 170
m2/g to 220
m2/g.
[0079] Hydroprocessing the specified amounts of third mixture and utility
fluid using
the specified hydroprocessing catalyst leads to improved catalyst life, e.g.,
allowing the
hydroprocessing stage to operate for at least 3 months, or at least 6 months,
or at least 1
year without replacement of the catalyst in the hydroprocessing or contacting
zone.
Catalyst life is generally > 10 times longer than would be the case if no
utility fluid were
utilized, e.g.,? 100 times longer, such as? 1000 times longer.
[0080] The hydroprocessing is carried out in the presence of hydrogen,
e.g., by (i)
combining molecular hydrogen with the third mixture and/or utility fluid
upstream of the
hydroprocessing and/or (ii) conducting molecular hydrogen to the
hydroprocessing stage in
- 30 -
CA 02843515 2015-08-21
one or more conduits or lines. Although relatively pure molecular hydrogen can
be utilized
for the hydroprocessing, it is generally desirable to utilize a "treat gas"
which contains
sufficient molecular hydrogen for the hydroprocessing and optionally other
species (e.g.,
nitrogen and light hydrocarbons such as methane) which generally do not
adversely
interfere with or affect either the reactions or the products. Unused treat
gas can be
separated from the hydroprocessed product for re-use, generally after removing
undesirable
impurities, such as H2S and NH3. The treat gas optionally contains > about 50
vol. % of
molecular hydrogen, e.g., > about 75 vol. %, based on the total volume of
treat gas
conducted to the hydroprocessing stage.
[0081] Optionally, the amount of molecular hydrogen supplied to the
hydroprocessing
stage is in the range of from about 300 SCF/B (standard cubic feet per barrel)
(53 S m3/m3)
to 5000 SCF/B (890 S m3/m3), in which B refers to barrel of feed to the
hydroprocessing
stage (e.g., third mixture plus utility fluid). For example, the molecular
hydrogen can be
provided in a range of from 1000 SCF/B (178 S m3/m3) to 3000 SCF/B (534 S
m3/m3).
Hydroprocessing the third mixture in the presence of the specified utility
fluid, molecular
hydrogen, and a catalytically effective amount of the specified
hydroprocessing catalyst
under catalytic hydroprocessing conditions produces a hydroprocessed product
including,
e.g., upgraded SCT. An example of suitable catalytic hydroprocessing
conditions will now
be described in more detail. The invention is not limited to these conditions,
and this
description is not meant to foreclose other hydroprocessing conditions within
the broader
scope of the invention.
[00821 The hydroprocessing is generally carried out under hydroconversion
conditions,
e.g., under conditions for carrying out one or more of hydrocracking
(including selective
hydrocracking), hydrogenation, hydrotreating, hydrodesulfurization,
hydrodenitrogenation,
hydrodemetallation, hydrodearomatization, hydroisomerization, or hydrodewaxing
of the
specified third mixture. The hydroprocessing reaction can be carried out in at
least one
vessel or zone that is located, e.g., within a hydroprocessing stage
downstream of the
pyrolysis stage and separation stage. The specified third mixture generally
contacts the
hydroprocessing catalyst in the vessel or zone, in the presence of the utility
fluid and
molecular hydrogen. Catalytic hydroprocessing conditions can include, e.g.,
exposing the
-31 -
CA 02843515 2015-08-21
combined diluent-third mixture to a temperature in the range from 50 C to 500
C or from
200 C to 450 C or from 220 C to 430 C or from 350 C to 420 C proximate to the
molecular hydrogen and hydroprocessing catalyst. For example, a temperature in
the range
of from 300 C to 500 C, or 350 C to 430 C, or 360 C to 420 C can be utilized.
Liquid
hourly space velocity (LHSV) of the combined diluent-third mixture will
generally range
from 0.1 to 30
h-I, or 0.4 11-I to 25 h-I, or 0.5 1-11 to 20 h-I. In some embodiments,
LHSV is at least 5 h-I, or at least 10 hH, or at least 15 h'. Molecular
hydrogen partial
pressure during the hydroprocessing is generally in the range of from 0.1 MPa
to 8 MPa,
or 1 MPa to 7 MPa, or 2 MPa to 6 MPa, or 3 MPa to 5 MPa. In some embodiments,
the
partial pressure of molecular hydrogen is < 7 MPa, or < 6 MPa, or < 5 MPa, or
< 4 MPa, or
< 3 MPa, or < 2.5MPa, or < 2 MPa. The hydroprocessing conditions can include,
e.g., one
or more of a temperature in the range of 300 C to 500 C, a pressure in the
range of 15 bar
(absolute) to 135 bar, or 20 bar to 120 bar, or 20 bar to 100 bar, a space
velocity (LHSV) in
the range of 0.1 to 5.0, and a molecular hydrogen consumption rate of about 53
standard
cubic meters/cubic meter (S m3/m3) to about 445 S m3/m3 (300 SCF/B to 2500
SCF/B,
where the denominator represents barrels of the third mixture, e.g., barrels
of SCT). In one
or more embodiment, the hydroprocessing conditions include one or more of a
temperature
in the range of 380 C to 430 C, a pressure in the range of 21 bar (absolute)
to 81 bar
(absolute), a space velocity in the range of 0.2 to 1.0, and a hydrogen
consumption rate of
about 70 S m3/m3 to about 267 S m3/m3 (400 SCF/B to 1500 SCF/B). When operated
under these conditions using the specified catalyst, TH hydroconversion
conversion is
generally 25.0% on a weight basis, e.g., > 50.0%.
Hydroprocessed Product
[0083] In
certain embodiments, an effluent is conducted away from the
hydroprocessing stage(s), the effluent comprising liquid-phase and vapor-phase
portions.
The vapor-phase portion is generally separated from the effluent, e.g., by one
or more
vapor-liquid separators, and conducted away. Treat gas can be separated from
the vapor
portion for recycle and re-use, if desired.
[0084] In certain embodiments, a mixture comprising light hydrocarbons
(a "light
hydrocarbon mixture") is separated from the liquid-phase portion of the
hydroprocessor
- 32 -
CA 02843515 2015-08-21
effluent, the light hydrocarbon mixture comprising > 90.0 wt. % of the liquid
phase's
molecules having atmospheric boiling point < 300 C based on the weight of the
liquid-
phase portion of the hydroprocessor effluent. The conversion product, i.e.,
the remainder
of the liquid-phase portion of the hydroprocessor effluent following
separation of the light
hydrocarbon mixture generally comprises a hydroprocessed product.
[0085] In certain embodiments, hydroprocessed product comprises:? 10.0 wt.
% based
on the weight of the hydroprocessed product, e.g., > 20.0 wt. %, such as 20.0
wt. % to 40.0
wt. %, of one or more of (i) compounds in the 1.0 ring molecular class, (ii)
compounds in
the 1.5 ring molecular class, (iii) compounds defined in (i) or (ii) and
further comprising
one or more alkyl or alkenyl substituents on any ring, (iv) compounds defined
in (i), (ii) or
(iii) and further comprising hetero atoms selected from sulfur, nitrogen or
oxygen. The
hydroprocessed product can have, e.g., a viscosity? 2.0 cSt at 50 C, e.g., in
the range of
3.0 cSt to 50.0 cSt at 50 C. Generally, > 1.0 wt. % of the hydroprocessed
product
comprises compounds having an atmospheric boiling point? 565 C, e.g., 2.0 wt.
% to 10.0
wt. % based on the weight of the hydroprocessed product. The hydroprocessed
product can
comprise, e.g., < 50.0 wt. %, based on the weight of the hydroprocessed
product, of
compounds in the ring molecular classes of from 3.0 to 5.0, including those
compounds
having (i) one or more alkyl or alkenyl substituents on any ring and/or (ii)
one or more
hetero atoms selected from sulfur, nitrogen or oxygen. The hydroprocessed
product can
comprise, e.g., 20.0 wt. % to 40.0 wt. % of molecules having a number of
aromatic rings in
the range of from 3.0 to 5.0, based on the weight of the hydroprocessed
product.
Depending primarily on the third mixture's sulfur content, the hydroprocessed
product can
have, e.g., a sulfur content in the range of 0.01 wt. % to 3.5 wt. % based on
the weight of
the product.
[0086] In certain embodiments, the hydroprocessed product has a sulfur
content that is
< 0.5 times (wt. basis) that of the third mixture and a TH content < 0.7 times
the TH
content of the third mixture. Generally, the hydroprocessed product comprises
> 20.0 wt.
% of the liquid-phase portion of the hydroprocessor effluent (based on the
weight of the
liquid-phase portion of the hydroprocessor effluent), e.g., > 40.0 wt. %, such
as in the range
of 20.0 wt. % to 70.0 wt. % or in the range of 40.0 wt. % to 60.0 wt. %. When
the
- 33 -
CA 02843515 2015-08-21
hydroprocessing is operated under the conditions specified in the preceding
section
utilizing as a feed the specified third mixture (e.g., an SCT stream),
hydroprocessed
product generally has a density? 0.97 g/cm3 at 15 C, such as o? 1.00 g/cm3 at
15 C, and a
viscosity < 90.0 % that of the third mixture's viscosity, e.g., < 75.0 % that
of the third
mixture's viscosity. Generally,? 50.0 wt. % the hydroprocessed product is in
the form of
multi-ring aromatic and non-aromatic molecules having a number of carbon atoms
> 16
based on the weight of the hydroprocessed product, e.g.,? 75.0 wt. %, such as?
90.0 wt.
%. Optionally, > 50.0 wt. % the hydroprocessed product is in the form of multi-
ring
molecules. These can have, e.g., a number of carbon atoms in the range of from
25 to 40
based on the weight of the hydroprocessed product.
[0087] If
desired, at least a portion of the light hydrocarbon mixture and/or at least a
portion of the hydroprocessed product can be utilized within the process
and/or conducted
away for storage or further processing. For example, the relatively low
viscosity of the
hydroprocessed product compared to that of the third mixture can make it
desirable to
utilize at least a portion of the hydroprocessed product as a diluent (e.g., a
flux) for heavy
hydrocarbons, especially those of relatively high viscosity. In
this regard, the
hydroprocessed product can substitute for more expensive, conventional
diluents. Non-
limiting examples of heavy, high-viscosity streams suitable for blending with
the
hydroprocessed product (or with the entire liquid-phase portion of the
hydroprocessor
effluent) include one or more of bunker fuel, burner oil, heavy fuel oil
(e.g., No. 5 or No. 6
fuel oil), high-sulfur fuel oil, low-sulfur fuel oil, regular-sulfur fuel oil
(RSFO), and the
like. In an embodiment, the hydroprocessed product is utilized in a blend, the
blend
comprising (a)? 10.0 wt. % of the hydroprocessed product and (b)? 10.0 wt. %
of a fuel
oil having a sulfur content in the range of 0.5 wt. % to 3.5 wt. and a
viscosity in the range
of 100 cSt to 500 cSt at 50 C, the weight percents being based the weight of
the blend.
[0088] In an
embodiment, the hydroprocessed product can be utilized for fluxing and
conducting away a high-viscosity bottoms from a vapor-liquid separation
device, such as
those integrated with a pyrolysis furnace. In certain embodiments, > 10.0% of
the
hydroprocessed product (on a wt. basis) e.g.,? 50.0%, such as? 75.0%, can be
combined
with? 10.0% (on a wt. basis) of the bottoms fraction, e.g., > 50.0%, such as?
75.0%, in
- 34 -
CA 02843515 2015-08-21
order to lessen the bottom's viscosity. In certain embodiments, at least a
portion of the
light hydrocarbon mixture is recycled upstream of the hydroprocessing stage
for use as all
or a portion of the utility fluid. For example,?: 10.0 wt. % of the light
hydrocarbon mixture
can be utilized as the utility fluid, such as?: 90.0 wt. %, based on the
weight of the light
hydrocarbon mixture. When the amount of light hydrocarbon mixture is not
sufficient to
produce the desired amount of utility fluid, a make-up portion of utility
fluid can be
provided to the process from another source.
[0089] In one or more embodiments, low and high boiling-range cuts are
separated
from at least a portion of the hydroprocessed product, e.g., at a cut point in
the range of
about 320 C to about 370 C, such as about 334 C to about 340 C. With a cut
point in this
range, > 40.0 wt. % of the hydroprocessed product is generally contained in
the lower-
boiling fraction, e.g.,?: 50.0 wt. %, based on the weight of the
hydroprocessed product. At
least a portion of the lower-boiling fraction can be utilized as a flux, e.g.,
for fluxing
vapor/liquid separator bottoms, primary fractionator bottoms, etc. At least a
portion of the
higher-boiling fraction can be utilized as a fuel, for example.
[0090] Alternatively, or in addition, the process can further comprise
hydrogenating or
treating at least a portion of the hydroprocessed product of any the above
embodiments to
produce a naphthenic lubricating oil.
Example 1
[0091] This example illustrates the conversion of steam cracked tar to
hydroprocessed
product.
[0092] The hydroprocessing is carried out in a fixed bed reactor having an
approximately 0.3" ID (inside diameter) stainless tube reactor body and three
heating
blocks. The reactor was heated by a three-zone furnace. Table 1 shows details
of the
catalyst used in the experiment. 12.6 g (17.5 cm3) of RT-621, sized to 40-60
mesh, was
loaded into the zone of the reactor within the furnace.
- 35 -
CA 02843515 2015-08-21
[0093] Table 1 Catalyst Description
Catalyst RT-621
Size 1/16" cylindrical extrudate, sized to 40-60 mesh for
testing
Catalyst volume 17.5 cm3
Catalyst weight 12.6 g
[0094] After loading the reactor, the unit is pressure tested at 1000 psig
(68.9 bar
gauge) with molecular nitrogen followed by molecular hydrogen. The catalyst
was
sulfided with a 200 cm3 of sulfiding solution containing 80 wt. % 130N
lubricating oil
basestock and 20 wt. % ethyldisulfide (FW 122.25, S=32.06, 10.5 wt. % S, 0.324
mole
S/100 cm3 feed) based on the weight of the sulfiding solution. The details are
as follows.
1. Set reactor pressure 750 psig (51.7 bar gauge).
2. Start ISCO pump containing 200 cm3 of sulfiding solution at 60 cm3/hr
for
about one hour until the pressure transducer reaches 750 psig (51.7 bar gauge)
(to
soak the catalyst at ambient temperature of approximately 25 C).
3. Reduce ISCO pump rate to 2.5 cc/hr. Start molecular hydrogen flow at 20
SCCM.
4. Catalyst Sufiding:
Ramp reactor from room temperature to 110 C at 1 C/ min, hold at 110 C
for 1 hr (duration: 2.5 hr.);
Ramp reactor from 110 C to 250 C at 1 C/min, hold at 250 C for 12 hr.
(duration: 14h and 20 mm., with most of the sulfiding occurring at 250 C);
Ramp reactor from 250 C to 340 C at 1 C /min, and hold at 340 C until the
pump is empty (duration of about 1.5 hr. + final holding at 340 C).
[0095] After sulfiding, a feed (60 wt. % SCT/40 wt. % trimethylbenzene) was
introduced at 6.0 cm3/hr. (0.34LHSV), the molecular hydrogen flow was
increased to 54
cm3/min (3030 SCF/B), the reactor temperature was ramped up at 1 C/min to 425
C while
the reactor pressure was maintained at 750 psig (51.7 bar gauge). Table 2
shows the
properties of 1,2,4-trimentylbenzene used as the utility fluid in the
experiment.
[0096] Table 2. Utility Fluid Description
Solvent 1,2,4-Trimethylbenzene (TMB)
CAS # 95-63-6
Source Aldrich, T7360-1
Purity. 98% min
- 36 -
CA 02843515 2015-08-21
MO1. Wt. 120.2
Density 0.889
Boiling point, C 168
Critical temperature, C 377
[0097] A SCT sample is obtained from a commercial steam cracker primary
fractionator bottoms stream. Table 3 lists the typical properties for the SCT
sample. Note
that the sample contains about 2.2 wt. % of sulfur and a viscosity of 988 cSt
at 50 C.
[0098] Table 3. Summary of properties for SCT feed and hydroprocessed
product.
SCT feed hydroprocessed hydroprocessed
product product
Days on Stream 8 20
Reaction Temp., C 425 400
Reaction Pressure, psig 768 (52.9) 1002 (69.09))
(bar g)
LHSV, hr-1 0.34 0.34
H2 circulation, SCF/B 3032 1011
Sulfur, wt. % 2.2 0.06 0.30
Viscosity at 50 C 1 988 5.8 12.8
[0099] The liquid-phase portion of the hydroprocessor effluent (total
liquid product or
"TLP") is collected from the units at intervals. For several such TLP samples
the
trimethylbenzene is removed by rotary evaporation to yield an essentially
solvent-free
hydroprocessed product. Analytical tests are performed at different times
during the run to
determine, e.g., sulphur content, viscosity, hydroprocessed product
composition by 2D GC,
and conversion by simulated distillation, for the hydroprocessed product.
[00100] The hydroprocessed product composition is determined by the
combined use of
2D GC and simulated distillation. 2D GC quantified the molecules that boil
below roughly
565 C (1050 F) while simulated distillation determined the amount of
hydroprocessed
product fraction that boils above 565 C (1050 F). Table 4 summarizes the
compositional
results for two hydroprocessed product samples taken during the run at 8 and
20 days-on-
stream in addition to the composition of the feed. "Sats" refers to paraffinic
molecules and
565 C+ refers to the amount of hydroprocessed fraction that boils above 565 C
(1050 F).
- 37 -
CA 02843515 2015-08-21
[00101] Table 4
SCT Tar Hydroprocessed
Hydroprocessed
Product Product
Days on stream 8 20
Species wt. % wt. % wt. %
Sats 1.3 3.8 3.5
1-Ring 0.3 15.3 9.2
1.5-Ring 1.3 16.4 16.8
2.0-Ring 17.5 19.8 18.1
2.5-Ring 11.6 15.9 15.2
3.0-Ring 24.0 12.2 12.8
3.5-Ring 10.7 8.2 8.9
4.0-Ring 8.2 2.9 3.7
4.5-Ring 6.2 1.7 2.1
5.0-Ring 2.7 0.9 1.5
5.5-Ring 0.7 0.3 0.4
565 C+ 15.5 2.6 7.4
[00102] Note that there is significant reduction in heavy molecules,
including 4-ring
plus molecules. However, the most notable from the compositional changes after
the
hydroprocessed reactions is the significant increase in 1-ring and 1.5-ring
aromatics. For
example, the feed contains very little 1- and 1.5-ring aromatics (1.6 wt.%).
After the
hydroprocessed reaction, the sum of 1-ring and 1.5-ring aromatics increased
significantly to
31.7 wt. % for 8 days-on-stream sample, and to 26 wt. % for the 20 days-on-
stream sample.
The change in the sum of 1 ring and 1.5 ring aromatics is 1900% and 1500%,
respectively,
for the 8 and 20 days-on-stream samples. The conversion of tar heavies to
lighter
molecules such as 1-ring and 1.5-ring aromatics is believed to be the reason
that leads to
the significant reduction in viscosity of hydroprocessed product.
[00103] The two hydroprocessed product compositions have a viscosity of
5.8 cSt at
50 C for the 8 DOS sample and 12.8 cSt at 50 C for the 20 DOS sample,
respectively.
Compared with typical specifications for RSFO, the hydroprocessed products
have a
significant viscosity premium. Hydrocarbon processors typically use expensive
streams
such as kerojet as flux to blend high viscosity hydrocarbon streams such as
vacuum resid to
meet fuel oil viscosity spec.
[00104] Alternatively, one can separate the hydroprocessed product into a
flux fraction
and a heavy bottom fraction, e.g., using fractionation. For ease of
comparison, the
- 38 -
CA 02843515 2015-08-21
viscosity of the flux fraction is set to be equal to that of SCGO while the
heavy bottom
fraction to be equal to the tar feed viscosity.
[00105] Note that roughly 54 wt. % of the 8 DOS sample is upgraded to SCGO
flux
value while the rest (the heavy bottom) is equivalent to the tar starting
materials. For the
20 DOS sample, the amount of flux upgrade is ca. 40 wt. %.
[00106] There are advantages with an added separation step. For example,
the heavies
in hydroprocessed products might cause a compatibility issue with fuel oil,
which leads to
precipitation of heavies in fuel oil after blending. By separating the
hydroprocessed
product into a light fraction and a heavy fraction, one monetizes the much
higher value
with the flux upgrade. The heavy fraction is used in the same way as tar would
have been
used, e.g., as carbon black feedstock or as boiler fuel.
[00107] While the illustrative forms disclosed herein have been described
with
particularity, it will be understood that various other modifications will be
apparent to and
can be readily made by those skilled in the art. Accordingly, the scope of the
claims should
not be limited by particular embodiments set forth herein, but should be
construed in a
manner consistent with the specification as a whole.
[00108] When numerical lower limits and numerical upper limits are listed
herein,
ranges from any lower limit to any upper limit are contemplated.
- 39 -
