Note: Descriptions are shown in the official language in which they were submitted.
21~6~10
DELAYED COKING OF BOTTOMS PRODUCT FROM A
HYDROTREATMENT PROCESS
(D# 92069-F)
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a delayed coking
process. More particularly, this invention relates
to a process wherein a sulfur- and metals-containing
hydrocarbon feed is, in a hydroprocessing operation,
contacted with hydrogen and a catalyst having 1.0 -
5.0 wt. % of an oxide of nickel or cobalt and 10.0 -
25.0 wt. % of an oxide of molybdenum supported on a
porous alumina support and having a specified pore
size distribution thereby forming a hydrotreated/
hydrocracked product and finally subjecting the bottoms
product recovered from the hydrotreated/hydrocracked
product in a delayed coking process to yield coke,
distillate and gas.
2. Prior Art
U.S. Pat. No. 4,941,964, incorporated herein
2146410
by reference, discloses a process for the hydro-
treatment of a sulfur- and metal-containing hydrocarbon
feed which comprises contacting the feed with
hydrogen and a catalyst in a manner such that the
catalyst is maintained at isothermal conditions and
is exposed to a uniform quality of feed. The catalyst
has a composition comprising 3.0 - 5.0 wt. % of an
oxide of a Group VIII metal, 14.5 - 24.0 wt. % of an
oxide of a Group VIB metal and 0 - 2.0 wt. ~ of an
oxide of phosphorus supported on a porous alumina
support, and the catalyst is further characterized by
having a total surface area of 150 - 210 m /g and a
total pore volume (TPV) of 0.50 - 0.75 cc/g with a
pore diameter tistribution such that micropores having
diameters of 100 - 160A constitute 70 - 85% of the
total pore volume of the catalyst and macropores
having diameters of greater than 250A constitute
5.5 - 22.0 % of the total pore volume of the catalyst.
U.S. Pat. No. 4,670,132 (Arias et al.)
discloses a catalyst preparation and a catalyst
composition useful in the hydroconversion of heavy
oils, the catalyst comprising a high iron content
bauxite with the addition of one or more of the
following promoters: phosphorus, molybdenum, cobalt,
--2--
214641 0 -
nickel or tungsten. The bauxite catalysts typically
contain 25 - 35 wt. % aluminum. The catalysts have
certain characteristic features for the elemental
components (including aluminum and where present,
molybdenum) when the pellet exteriors aTe examined in
the fresh oxide state using X-ray photoelectron
spectroscopy (XPS). For those catalysts which contain
molybdenum, the surface Mo/Al atomic ratios on the
pellet exteriors are in the range of 0.03 to 0.09.
Arias is distinguished from the instant invention in
that its catalyst requires a bauxite support whereas
the catalyst of the instant invention does not. In
addition, Arias requires a surface Mo/Al atomic ratio
on the pellet exteriors in the range of 0.03 to 0.09
when the fresh oxide catalyst is examined by XPS
whereas the catalysts of the instant invention are
characterized by ~l) bul~ Mo/Al atomic ratios of 0.06 -
0.075 as measured by traditional techniques; (2)
surface Mo/Al atomic ratios on the pellet exteriors
of 0.20 - 0.55 as measured by XPS on the fresh oxide
catalysts; (3) surface Mo/Al atomic ratios on the
crushed catalyst pellets of 0.10 - 0.15 as measured
by XPS on the fresh crushed oxide catalysts, and,
(4) that the ratio of the surface Mo/Al atomic ratios
--3--
21~6410
of the pellet exteriors relative to the surface
Mo/Al atomic ratios of the crushed catalyst pellets
be less than 6Ø
U.S. Pat. No. 4,652,545 (Lindsley et al.),
incorporated herein by reference, discloses a catalyst
composition useful in the hydroconversion of heavy
oils, the catalyst containing 0.5 - 5 ~ Ni or Co and
1.8 - 18 % Mo (calculated as the oxides) on a porous
alumina support, having 15 - 30 ~ of the Ni or Co in
an acid extractable form, and further characterized
by having a TPV of 0.5 - 1.5 cc/g with a pore diameter
distribution such that ti) at least 70 % TPV is in
pores having 80 - 120A diameters, (ii) less than 0.03
cc/g of TPY (6% TPV) is in pores having diameters of
less than 80A, and (iii) 0.05 - 0.1 cc/g of TPV
(3 - 20 % TPV) is in pores having diameters of greater
than 120A. Lindsley et al. is distinguished from
the instant invention in that although it teaches that
having a proportion of nickel or cobalt contained in
its catalyst in an acid extractable form is
advantageous in terms of heavy oil hydroconversion.
Lindsley et al. does not teach or suggest that catalysts
which have a prescribed molybdenum gradient are
--4--
21~6~10
advantageous in terms of heavy oil hydroconversion.
U.S. Pat. No. 4,588,709 (Morales et al.)
discloses a catalyst preparation and a catalyst
composition useful in the hydroconversion of heavy
oils, the catalyst comprising 5 - 30 wt. % of a Group
VIB element (e.g., molybdenum) and 1 - 5 wt. % of a
Group VIII element (e.g., nickel). Morales et al.
indicate that the finished catalysts have average pore
diameters of 150 to 300 Angstroms. The catalysts have
certain characteristic features for the active
components (Mo and Ni) when the pellet exteriors are
examined in a sulfided state using X-ray photoelectron
spectroscopy (XPS). Morales ('709) is distinguished
from the instant invention in that its catalyst
requires a large average pore diameter (150 to 300
Angstroms) whereas the catalyst of the instant
invention has median pore diameters of 120 to 130
Angstroms. In addition, Morales ('709) requires
certain characteristic XPS features of the pellet
exteriors after presulfiding whereas the catalyst of
the instant invention requires a specified molybdenum
gradient as determined by measuring the molybdenum/
aluminum atomic ratios ~y XPS for the catalyst pellet
21q6~10 --
exteriors and the pellets in a crushed form as
measured on the fresh catalysts in an oxide state.
U.S. Pat. No. 4,579,649 (Morales et al.)
discloses a catalyst preparation and a catalyst
composition useful in the hydroconversion of heavy
oils, the catalyst containing a Group VIB element
(e.g., molybdenum), a Group VIII element (e.g.,
nickel) and phosphorus oxide on a porous alumina
support. The catalyst has certain characteristic
features for the three active components (Mo, Ni and
P) when the pellet exteriors are examined in a
sulfided state using X-ray photoelectron spectroscopy
(XPS). Morales ('649) is distinguished from the instant
invention in that its catalyst requires phosphorus
whereas the catalyst of the instant invention does not.
In addition, Morales ('649) requires certain
characteristic XPS features of the pellet exteriors
after presulfiding whereas the catalysts of the
instant invention require a specified molybdenum
gradient as determined by measuring the molybdenum/
aluminum atomic ratios by XPS for the catalyst pellet
exteriors and the pellets in a crushed form as
measured on the fresh catalysts in an oxide state.
- 2146410
U.S. Pat. No. 4,520,128 (Morales et al.)
discloses a catalyst preparation and a catalyst
composition useful in the hydroconversion of heavy
oils, the catalyst containing 5 - 30 wt. % of a Group
S VIB element ~e.g., molybdenum), 0.1 - 8.0 wt. % of a
Group VIII element ~e.g., nickel) and 5 - 30 wt. %
of a phosphorus oxide on a porous alumina support. The
finished catalysts of Morales t'128) have mean pore
diameters of 145 to 154 Angstroms. The catalyst has
certain characteristic features for the three active
components CMo, Ni and P) when the pellet exteriors
are examined in a sulfided state using X-ray photo-
electron spectroscopy ~XPS). Morales ('128) is
distinguished from the instant invention in that its
catalyst requires phosphorus whereas the catalyst of
the instant invention does not. Morales ('128) also
requires a large mean pore diameter (145 to 154
Angstroms) whereas the catalyst of the instant
invention has median pore diameters of 120 to 130
Angstroms. In addition, Morales ('128) requires
certain characteristic XPS features of the pellet
exteriors after presulfiding whereas the catalysts of
the instant invention require a specified molybdenum
gradient as determined by measuring the molybdenum/
_ 7 _
- 2146410
aluminum atomic ratios by XPS for the catalyst pellet
exteriors and the pellets in a crushed form as
measured on the fresh catalysts in an oxide state.
A wide variety of delayed coking operations
have been described in the art. In a typical delayed
coking process a heavy liquid hydrocarbon fraction is
converted to solid coke and lower boiling liquid and
gaseous products. Generally, the coker feedstock is
a residual petroleum based oil or a mixture of
residual oil with other heavy fractions.
In a typical delayed coking process, the
residual oil is heated by exchanging heat with liquid
products from the process and is fed into a
fractionating tower wherein light end products are
removed from the residual oil. The residual oil is
then pumped from the bottom of the fractionating
tower through a tube furnace where it is heated under
pressure to coking temperature and discharged into a
coking drum.
In the coking reaction the residual feedstock
is thermally decomposed into solid coke, condensable
liquid and gaseous hydrocarbons. The solid coke is
2146~10
recovered. Coke quality determines its use. High
purity coke is used to manufacture electrodes for the
aluminum and steel industry. Lower purity coke is
used for fuel; its value calculated based on the sulfur
and heavy metal impurities which are transferred from
the feedstock to the coke.
The liquid and gaseous hydrocarbons are
removed from the coke drum and returned to the
fractionating tower where they are separated into the
desired hydrocarbon fractions.
U.S. Pat. No. 4,332,671 to L. D. Boyer
teaches a delayed coking process in which a heavy
high-sulfur crude oil is first atmospheric distilled
and then vacuum distilled to produce feedstock for
delayed coking. Vapor and liquid products of delayed
coking are subjected to hydrotreating to yield lower
sulfur liquid and gas products.
U.S. Pat. No. 3,907,664 to H. R. Janssen
et al. teaches a control system for a delayed coker
fractionator. In particular, a coker fractionator
overhead vapor fraction is condensed. .The uncondensed
vapor is passed from the accumulator to gas recovery.
_g_
2146410
A portion of the condensed liquid is used to reflux
the coker fractionator. The remaining portion of
condensed liquid is passed to gas recovery.
U.S. Pat. No. 4,686,027 to J. A. Bonilla
et al. teaches a delayed coker process. An overhead
fraction from the coker fractionator is cooled,
compressed and passed to an absorber/stripper. The
vapor product of the absorber/stripped is a fuel gas
stream. Fuel gas typically comprises methane and
ethane.
The liquid product of the absorberlstripper
is passed to a stabilizer which produces a C3/C4
overhead product and total naphtha as a bottoms product.
-10-
- - 2146410
SUMMARY OF THE INVENTION
The instant invention is a delayed coking
process in which a sulfur- and metals-containing
hydrocarbon feedstock is treated in a catalytic hydro-
processing operation thereby forming a hydrotreated/hydrocracked product from which there is recovered a
bottoms product having a boiling point greater than
1000 F which in a final process step is subjected
in a delayed coking operation to yield coke,
distillate and gas.
DETAILED DESCRIPTION OF THE INVENTION
The process of the instant invention is a
process for delayed coking of a bottoms product having
a boiling point of 1000 F, which comprises:
a) hydroprocessing a sulfur- and
metals-containing hydrocarbon feed in a hydroprocessing
process which comprises contacting said feed with
hydrogen and a catalyst in a manner such that the
catalyst is maintained at isothermal conditions and is
exposed to a uniform quality of feed, where said
catalyst has a composition comprising 1.0 - 5.0 weight
21~6410
percent of an oxide of nickel or cobalt and 10.0 - 25.0
weight percent of an oxide of molybdenum, all supported
on a porous alumina support in such a manner that the
molybdenum gradient of the catalyst has a value of
less than 6.0, 15 - 30 ~ of the nickel or cobalt is
in an acid extractable form, and said catalyst is
further characterized by having a total surface area
of 150 - 210 m /g, a total pore volume of 0.50 -
0.75 cc/g, and a pore size distribution such that
pores having d1ameters of less than lOOA constitute
less than 25.0 %~ pores having diameters of 100 -
160A constitute 70.0 - 85.0 % and pores having
diameters of greater than 250A constitute 1.0 -
15.0 % of the total pore volume of said catalyst
thereby forming a hydrotreated-hydrocracked product
containing a gaseous phase product and a liquid phase
product,
b) recovering from the liquid phase product
a bottoms product having a boiling point greater than
1000 F,
c) subjecting said bottoms product in a
delayed coking process to yield coke, distillate and
gas.
2146410
It is one feature of the catalyst
composition employed in the hydroprocessing step of the
instant invention that it has a specific molybdenum
gradient (as herein defined) from the interior to
the exterior of a given catalyst pellet. It is
another feature of the catalyst composition that 15 -
30 % of the nickel or cobalt contained in the
catalyst is in an acid extractable form. It is yet
another feature of the catalyst composition that it
has a specified pore size distribution such that
pores having diameters less than lOOA constitute less
than 25.0 %, pores having diameters of 100 - 160A
constitute 70.0 - 85.0 %, and pores having diameters
of greater than 250A constitute 1.0 - 15.0 % of the
total pore volume of the catalyst. It is a feature
of the method of the instant invention that the
above-described catalyst is contacted with a
hydrocarbon feedstock and hydrogen in the hydro-
processing step in such a manner as to expose the
catalyst to a uniform quality of feed and to maintain
the catalyst at isothermal temperature.
The above-described catalyst is advantageous
in the hydroprocessing step of this invention in that
2146410
it has a high activity for hydroprocessing heavy
hydrocarbon feedstocks including vacuum residua. The
hydroprocessing method of this invention (i.e.,
step (a)) is advantageous in that it enables the
attainment of improved levels of hydrodesulfurization
when hydroprocessing heavy feedstock such as vacuum
residua.
In one particularly preferred embodiment of
the process of the instant invention, a sulfur- and
metal-containing hydrocarbon feedstock is catalytically
hydroprocessed with the above-described catalyst
using the H-OIL process configuration. H-OIL is a
proprietary ebullated bed process (co-owned by
Hydrocarbon Research, Inc. and Texaco Development
Corp.) for the catalytic hydrogenation of residua and
heavy oils to produce upgraded distillate petroleum
products and a bottoms product suitable as coker feed
in the coking operation of the instant invention.
The ebullated bed system oper~tes under essentially
isothermal conditions and allows for exposure of
catalyst particles to a uniform quality of feed.
Petroleum feedstocks which may be treated
by the above-described catalyst in the hydroprocessing
-14-
2146410
step of the instant invention include naphthas,
distillates, gas oils, petroleum cokes, residual oils
and vacuum residua. A petroleum feedstock typical
of those subject to catalytic hydroprocessing by the
catalyst in the hydroprocessing step of the instant
invention is an Arabian Medium/Heavy Vacuum Resid
feedstock as set forth in Table I, below.
2146410
TABLE I
Typical Petroleum Feedstock
~Arabian Medium/Heavy Vacuum Resid)
API Gravity 4.8
1000 F. +, vol % 87.5
1000 F. +, wt. % 88.5
Sulfur, wt. % 5.0
Total Nitrogen, wppm 4480
Hydrogen, wt. % 10.27
Carbon, wt % 84.26
Alcor MCR, wt. % 22.2
Kinematic Viscosity cSt
Q 212 F 2430
@ 250 F 410
@ 300 F 117
Pour Point, F. 110
n-C5Insolubles, wt. % 28.4
n-C7Insolubles, wt. % 9.96
Toluene Insolubles, wt. %0.02
Asphaltenes, wt. % 9.94
Metals, wppm
Ni
Ccont'd.)
-16-
2146~10
TABLE I
(ConS ~ d . )
V 134
Fe 10
Cu 3
Na 49
Ch l o r i d e wppm
2146410
The catalyst composition employed in the
hydroprocessing step of the instant invention comprises
1.0 - 5.0 wt. %, preferably 2.5 - 3.5 wt. % of an
oxide of nickel or cobalt, preferably NiO and 10.0 -
25.0 wt. %, preferably 12.0 - 18.0 wt. % of an oxide
of molybdenum, most preferably MoO3, all supported on
a porous alumina support, most preferably a gamma-
alumina support. Other oxide compounds which may be
found in such a catalyst composition include SiO2
(present in less than 2.~ wt. %), S04 (present in less
than 0.8 wt. %~, and Na20 (present in less than 0.1
wt. %~. The above-described alumina support may be
purchased or prepared by methods well known to those
skilled in the art. Similarly, the support material
may be impregnated with the requisite amounts of the
above-described oxides of nickel, cobalt, and
molybdenum via conventional means known to those
skilled in the art. The catalyst composition of the
instant invention contains no bauxite and thus is
distinguishable from bauxite-containing catalysts such
as those described in U.S. Pat. No. 4,670,132.
A first necessary and essential feature of
the catalyst composition is that 15 - 30 % of the
nickel or cobalt present in the catalyst (relative to
-18-
2146410
the total nickel or cobalt present in the catalyst)
be acid extractable. As taught at Column 3, lines
7 - 35 of U.S. Pat. No. 4,652,545, it is the final
calcination temperature during preparation of the
catalyst which determines the percentage of free
nickel oxide or cobalt oxide (which is acid
extractable~ in the total catalyst composition.
Combined nickel or cobalt is not readily acid
extractable. As taught at Column 3, lines 36 - 40
of U.S. Pat. No. 4,652,545, it is theorized that
the above-described low proportion of acid extractable
nickel or cobalt prevents the catalyst from being
deactivated almost immediately with respect to
hydroconversion activity.
A second necessary and essential feature of
the catalyst composition is the specified pore size
distribution of the catalyst. It is well known to
those skilled in the art that the activity of a given
catalyst is proportional to its surface area and
active site density. Ordinarily, a catalyst with a
large proportion of micropores (defined herein as pores
with diameters less than 250A) will have a higher
surface area and a corresponding higher intrinsic
- 19 -
2146410
activity, whereas a catalyst having a large proportion
of macropores (defined herein as pores with diameters
greater than 250A) will have a lower surface area and
a corresponding lower intrinsic activity. However,
when hydroprocessing certain hydrocarbon feedstocks
such as petroleum feedstocks, particularly vacuum
resldua, the observed catalyst reaction rates for
catalysts with a large proportion of small diameter
pores are low due to diffusional limitations of the
small pores, as well as pore blockage caused by
accumulating carbon and metals as the catalyst ages.
The catalyst utilized in this invention has
a limited macroporosity sufficient to overcome the
diffusion limitations for hydroprocessing of the
largest molecules but not so much as to allow
poisoning of the catalyst pellet interiors.
The catalyst of the instant invention is
characterized by having a total surface area of 150 -
210 m2/g, preferably 170 - 205 m2/g, and a TPV of
0.50 - 0.75 cc/g, preferably 0.60 - 0.70 m2/g, with a
pore size distribution such that micropores having
diameters of 100 - 160A constitute 70 - 85%, preferably
70 - 80 % of the catalyst, and macropores
-20-
2146~10
having diameters of greater than 250A constitute 1.0 -
15.0 %, preferably 4.0 - 14.0 % TPV of the catalyst.
In such a catalyst, it is particularly preferred that
the pore volume of micropores having diameters less
than lOOA, be limited to less than 25.0 ~ TPV,
preferably 5.0 - 20.0 % TPV, most preferably 9.0 -
17.0 % TPV of the catalyst. The catalyst of the
instant invention has a median pore diameter of 120 -
130A, and thus is distinguishable from larger average
micropore diameter catalysts such as those disclosed
in U.S. Pat. Nos. 4,588,709 and 4,520,128.
A third necessary and essential feature of
the catalyst composition is that the above-described
oxide of molybdenum, preferably MoO3 is distributed
on the above-described porous alumina support in such
a manner that the molybdenum gradient of the catalyst
has a value of less than 6Ø As used in this
description and in the appended claims, the phrase
"molybdenum gradient" means that the ratio of a given
catalyst pellet exterior molybdenum/aluminum atomic
ratio to a given catalyst pellet interior molybdenum/
aluminum atomic ratio has a value of less than 6.0,
preferably 1.5 - 5.0, the atomic ratios being
21~6410
measured by X-ray photoelectron spectroscopy (XPS),
sometimes referred to as Electron Spectroscopy for
Chemical Analysis (ESCA). It is theorized that the
molybdenum gradient is strongly affected by the
impregnation of molybdenum on the catalyst support
and the subsequent drying of the catalyst during its
preparation. ESCA data on both catalyst pellet
exteriors and interiors were obtained on an ESCALAB
MKII instrument available from V. G. Scientific Ltd.,
1~ which uses a 1253.6 electron volt magnesium X-ray
source. Atomic percentage values were calculated
from the peak areas of the molybdenum 3p3/2 and
aluminum 2p3/2-1/2 signal5 using the sensitivity
factors supplied by Y. G. Scientific Ltd. The value
of 74.7 electron volts for aluminum was used as a
reference binding energy.
The catalyst employed in hydroprocessing
step (a) of this invention is more completely
described in Sherwood, Jr., et al., U.S. Patent No.
5,047,142 which is incorporated herein by reference
in its entirety.
In the hydroprocessing step of the instant
invention the above-described catalyst is contacted
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21~6410
with hydrogen and a sulfur- and metal-containing
hydrocarbon feedstock by any means which insures that
the catalyst is maintained at isothermal conditions
and exposed to a uniform quality of feed. Preferred
means for achieving such contact include contacting the
feed with hydrogen and the prescribed catalyst in a
single continuous stirred tank reactor or single
ebullated bed reactor, or in a series of 2 - 5
continuous stirred tank or ebullated bed reactors,
with ebullated bed reactors being particularly
preferred. This hydroprocessing process is particularly
effective in achieving high levels of desulfurization
with vacuum re~idua feedstocks.
lS In the delayed coking process of this
invention, the feedstock which is a bottoms product is
pumped at about 150 to 500 psig into a fired tube
furnace where it is heated to about 850 F. to 975 F.
and then discharged into a vertically oriented coking
drum through an inlet in the bottom head. The
pressure in the drum is maintained at 20 psig to 80
psig and the drum is insulated to reduce heat loss,
so that the coking reaction temperature remains
preferably between about 825 F. and 950 F. The hot
21~6410
feedstock thermally cracks over a period of several
hours, producing hydrocarbon vapors which rise through
the reaction mass and are removed from the top of the
coke drum and passed to a coker fractionator. In the
coker fractionator, the vapors are fractionally
distilled to yield condensable liquids and gases.
The material which does not vaporize and
remains in the vessel is a thermal tar. As the coking
reaction continues, the coke drum fills with thermal
tar which is converted over time at these coking
reaction conditions to coke. At the end of the coking
cycle, the coke is removed from the drum by cutting
with a high impact water jet. The cut coke is washed
to a coke pit and coke dewatering pad. The coke may
be broken into lumps and may be calcined at a
temperature of 2000 F. to 3000 F. prior to sampling
and analysis for grading.
Premium grade coke, referred to in the art
as needle grade coke, is used to make steel and for
specialty alloy applications. This p~oduct has a co-
efficient of thermal expansion of 0.5 x 10 7 to 5 x
m/cm/C., an ash content of O.OOl to n.o2 wt. %,
volatiles of about 3 to 6 wt. % and sulfur of about
-24-
21~6~10
0.1 to 1 wt. %.
Aluminum grade coke, referred to in the art
as anode grade coke, is used in the manufacturing of
aluminum. This product has a density of about 0.75
to 0.90 gm/cc, an ash content of about 0.05 to 0.3
wt. %, volatiles of about 7 to 11 wt. % and sulfur of
about 0.5 to 2.5 wt. %.
Fuel grade coke typically has an ash content
of about 0.1 to 2 wt. %, volatiles of about 8 to 20
wt. % and sulfur of about 1 to 7 wt. %.
Usually in the delayed coking operation of
this invention coking is conducted at temperatures
ranging from about 825 F. to 950 F. and at pressures
ranging from atmospheric up to about 80 psig.
Preferably, the coking operation is conducted at a
temperature of about 845 F. to about 865 F. and
at a pressure ranging from 0 psig to 20 psig.
Surprisingly, in the process of this
invention a substantial increase in the more valuable
liquid products from the coking operation is achieved
while at the same time the yield of the lower value
coke produced is reduced. Particularly advantageous
-25-
21~6~10
is the increase in the 400 - 650 F. liquid product
(i.e., the diesel fraction) from the coking step.
A further advantage of the process of the instant
invention is that a reduction of the total sulfur
content of the coker liquids and solid coke is
achieved.
-26-
2146410
-EXAMPLES
In Example 1 and Example 2 (Comparative)
H-OIL bottoms products (i.e., a 1000 F.~ product)
were taken from a nominal 5 BBL/Day two-stage H-OIL
pilot hydroprocessing unit runs in which an 85 wt. %/
15 wt. % mixture of virgin vacuum resid/fluid
catalytically cracked (FCC) heavy cycle gas oil was
fed to the H-OIL unit. The feedstock (i.e., the H-OIL
bottoms products utilized in the delayed coking
operation of Examples 1 and 2) were produced from an
Arabian-Medium/Arabian-Heavy mixture crude source. A
summary of the operating conditions for the H-OIL
unit is listed in Table I and the catalyst properties
of the catalysts employed are set out in Table II.
-27-
- 2146~10
TABLE I
OPERATING CONDITIONS
(HYDROPROCESSING UNIT)
Example 1 2
Catalyst Catalyst A* Catalyst B**
Run Number 912249 912214
Date on Test 06/29/91 05/18/91
Hours on Test 12 12
Number of Stages 2 2
Oper. Conditions
Average Reactor
Temperature, F 782 786
LHSVTotal Voil/Hr/
V reactor 0.383 0.384
LHSVFF ~ voil/Hr/
V reactor 0.326 0.323
CDSV, B/D/Lb 0.089 0.056
Average Catalyst Age,
Bbl/Lb 3.017 3.667
H2 Partial Pressure
Inlet, psia 2179 2159
Outlet, psia 1948 1946
Throughput Ratio
Vol (FF~VBR)/Vol (FF) 1.17 1.18
Gas Rates, SCFB Total/Hydrogen Total/Hydrogen
Make-up Gas 4893/3379 4465/4068
Rx Feed Gas 4203/3848 4019/3661
Quench Gas 520/488 507/448
Hydrogen Purge Gas 316/289 274/250
(Cont'd.)
-28-
- 21g6410
TABLE I
(Cont'd.)
Example 1 2
Run Number 912249 912214
Reactor Conditions*** RXl/RX2 RXl/RX2
Avg. rx. Temp., F 776/789 782/790
LHSVTotal ,V/Hr/V 0.77/0.77 0.77/0.77
FF 1 / / 0.65/0165 0.65/0.65
CDSV, B/D/Lb 0.12/0.14 0.10/0.11
Superficial Gas
Velocity, Ft/sec .057/.065 .055/.062
Cat. Age, BBl/Lb 7.19/7.48 7.06/7.46
Conversion
1000+ F Conv., Vl.% 57.2 56.8
1000+ Conv., wt% 57.0 56.3
Desulfurization wt % 92.8 81.6
Denitrogenation wt% 69.9 34.9
MCR Reduction, wt% 49.4 51.7
Demetallization wt~ 67.4 74.4
Nickel removal, wt% 64.4 39.8
Vanadium, wt% 25.4 15.7
1000- F in FF, vol% 33.3 34.1
Calc. H2 cons.,
SCFB 1646 1100
(Cont'd.)
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2146410
TABLE I
(Cont'd.)
* Catalyst of the instant invention.
* Catalyst B - HDS-1443B, a commercially available H-OIL
catalyst sold for use in hydroprocessing
resid oils by Criterion Catalyst Corp.
** where RXl is the first-stage reactor and RX2 is the
second-stage reactor.
HSV = liquid hourly space velocity as calculated by taking
the volume of feed oil charged to the hydroprocessing
unit per hour divided by the volume of the
hydroprocessing unit reactors.
FF = fresh feed or in this case 1000 F~ residuum feed.
DSV = catalyst daily space velocity as calculated by the
average number of barrels of total feed oil per day
per pound of catalyst in the hydroprocessing unit
reactors.
-30-
21~6410
TABLE II
CATALYST PROPERTIES
Catalyst Type Catalyst A Catalyst B
CHEMICAL PROPS.
Mo, wt% dry 10.5 8.77
Ni, wt% dry 2.5 2.42
SiJ wt% dry 1.1 0.1
S, wt% dIy 0.07 0.14
Na, wt% dry 0.04 0.04
PHYSICAL PROPS.
Avg. LengthJ in. 0.148 0.146
DiameterJ in. 0.037 0.0398
Length Distribution
< 0.5 mm, wt% 0.0 -
< 1.0 mm, wt% 0.0 0.0
< 1.6 mm, wt% 0.0 0.0
< 2.5 mm, wt% 6.6 40.71
> 15 mm, wt% 0.0 0.0
Compacted Bulk3
Density, lb/ft 40.8 36.1
Crush Strngth, lb/mm 1.8 1.5
Hg Pore Vol.J cc/g 0.64 0.74
(Cont'd.)
-31-
2146410
TABLE II
(Cont'd.)
Catalyst Type Catalyst A Catalyst B
PORE SIZE
DISTRIBUTION, cc/g (% TPV)
<100A 0.05 (8.5) 0.42 (56.8)
100-250A 0.54 (84.2) 0.08 (10.8)
>250A 0.05 (7.3) 0.24 (32.4)
250-500A 0.02 (3.9) 0.03 (4.1)
500-1500A 0.02 (2.5) 0.06 (8.1)
1500-4000A 0.005 (0,7) 0.08 (10.8)
> 4000A 0.001 (0.2) 0.07 (9.5)
Drum Attrition (#30
US Sieve), wt% 0.4 0.6
-32-
2146410
In Example 1 and Comparative Example 2
2500 gram samples of the 1000 F. bottoms product
recovered from the product of the hydroprocessing
operation were coked in glass flasks in which the
temperature was raised incrementally to a maximum of
850 F. and maintained at that temperature until
coking was complete after which high vacuum was applied
at the end of the run, the liquid produced in the
coking reaction was withdrawn and the coke recovered.
The liquids were fractionated in HYPERCAL ~
high efficiency glass columns. The fractions measured
were dry gas, butanes, pentanes, to 400 F naphtha,
400 F to 650 F light gas oil (diesel) and 650 F +
heavy gas oil.
The properties of the coker feedstocks
employed in Example 1 and in Comparative Example 2
are shown in Table III and the properties of the
products recovered from the delayed coking operation
in Examples 1 and 2 are set out in Table IY.
-- 2146410
TABLE III
COKER FEEDSTOCK PROPERTIES
EXAMPLE 1 2
H-OIL BOTTOMS H-OIL BOTTOMS
PRODUCT PRODUCT
CATALYST A CATALYST B
FEEDSTOCK catalyst
type
API GRAVITY, 0 4.6 2.9
SULFUR, WT% 2.08 2.72
NITROGEN, WPPM 4650 5272
CARBON, WT% 86.93 86.47
HYDROGEN, WT% 10.20 10.12
NITROGEN, WT% 0.40 0.49
CARBON RESIDUE, Wl~18.28 28.49
ASPHALTENES, WT~ 15.44 17.39
H/C RATIO, atomic 1.41 1.40
K.VIS. cSt, 212 F 2179 3477
250 F 500 751
300 F 134 173
PENTANE INSOL. WT% 34.66 36.79
HEPTANE INSOL. WT% 15.66 17.61
TOLUENE INSOL. WT% O.22 0.22
ICAP METALS, WPPM
Ni 42.8 47.7
V 58.5 58.6
(Cont'd.)
-34-
2146gl O
TABLE III
(Cont'd.)
EXAMPLE 1 2
H-OIL BOTTOMS H-OIL BOTTOMS
PRODUCT PRODUCT
CATALYST A CATALYST B
Fe 2.7 7.5
Mo < 1 <1
Cr < 1 ~1
Total metals 104 115
-3S-
2146410
TABLE IV
COKER PRODUCT QUALITIES
COKER NAPHTHA
EXAMPLE 1 2
H-OIL BOTTOMS H-OIL BOTTOMS
PRODUCT PRODUCT
CATALYST ACATALYST B
FEEDSTOCK/catalyst
type
SULFUR, WT% Ø07 O.ll
NITROGEN, WPPM 145 155
BASIC N2, WPPM 116 229
BROMINE NUMBER 3.1 5.7
RON (CLEAR) 40 44
MON (CLEAR) 46 44
CARBON (WT%) 84.26 83.42
HYDROGEN (WTS) 15.29 15.44
NITROGEN (WT~) 0.07 0.09
(Cont'd.)
-36-
- ` 2146410
TABLE IV
(Cont'd.)
COKER DIESEL
EXAMPLE H-OIL BOTTOMS H-OIL BOTTOMS
PRODUCT PRODUCT
CATALYST A CATALYST B
FEEDSTOCK/catalyst
type
SULFUR, WT% 0.74 1.03
NITROGEN, WPPM 720 739
ABSORBTIVITY @285 F 4.06 3.48
FIA AROMATICS, WT% 51.9 50.4
FIA OLEFINS, WT%5.3 4.3
FLASH POINT, F 188 174
ANILINE POINT, F119 119
CLOUD POINT, F -6 -6
POUR POINT, F -27 -13
CETANE 42 41
BROMINE NUMBER 2.4 3.5
BAS. NITROGEN, WPPM 444 489
KINEMATIC VISCOSITY
@ 40 C, cSt 2.73 2.63
@ 70 C, cSt 4.28 4.15
CARBON, WT% 86.62 86.36
HYDROGEN, WT%13.03 13.36
NITROGEN, WT% 0.10 0.11
(Cont'd.)
- 2146410
TABLE IV
(Cont'd.)
COKER HEAVY GAS OIL
EXAMPLE 1 2
H-OIL BOTTOMS H-OIL BOTTOMS
PRODUCT PRODUCT
CATALYST ACATALYST B
FEEDSTOCK~catalyst
type
SULFUR, WT% 2.79 1.67
NITROGEN, WPPM5876 520D
WATSON AROMATICS,
WT% 90.5 76.7
ANILINE POINT, F145 142
POUR POINT, F 80 64
BASIC N2, WPPM 473 650
KINEMATIC VISCOSITY
50 C, cSt 33 46
77 C, cSt 11 15
100 C, cSt 6 7
CARBON, WT% 87.19 86.85
HYDROGEN, WT~11.42 11.37
NITROGEN, WT% 0.08 0.2
REFRACTIVE INDEX,
70 C 1.5295 1.5393
(Cont'd.
-38-
214641 0
TABLE IV
(Cont'd.)
SOLID COKE
EXAMPLE 1 2
H-OIL BOTTOMS H-OIL BOTTOMS
PRODUCT PRODUCT
CATALYST ACATALYST B
FEEDSTOCK/catalyst
type
SULFUR, WT~ 2.98 3.92
MOISTURE, WT% 0.04 0.07
VOLATILE
CARBONACEOUS
MATERIAL, WT% 13.54 14.17
ICAP METALS, WPPM
NICKEL 55 58
VANADIUM 68 70
IRON ll 25
MOLYBDENVM 12 14
CHROMIUM
COEFPICIENT OF
THERMAL EXPANSION
(m/cm/C) 6.1 x 104.7 x 107
-39-
21~6~10
Yield and material balance data from
Examples 1 and 2 are presented in Table V which
follows. These data show that with the process of
this invention a substantial increase in the total
coker liquid product resulted while at the same time
the amount of less valuable coke formed was reduced
by 27% and the amount of less valuable heavy gas oil
was reduced by 29%. An improvement of 67% of the
more valuable diesel fraction was achieved. In
addition, the amount of sulfur removed from the coker
feed in non-dry gas stream (i.e., the C4~ product)
during the coking step increased to 26.8% in
Example 1 as compared to only 17.3% in Example 2.
-40-
21~6~10
TABLE V
EXAMPLE 1 2
Catalyst A Catalyst B
Coker Yields
(wt% FF)
Dry Gas 8.81 5.77
Total C4 0.63 2.29
Total C5 0.12 1.15
C6-400 F (naphtha) 15.95 11.11
400-650 F (diesel) 30.17 18.11
650 F+ liquid 17.52 24.71
Coke 26.89 36.84
Total 100.09 99.98
% Desulfurization
of feed to non-dry
gas products 26.79 17.30
- -41-
