Note: Descriptions are shown in the official language in which they were submitted.
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CATALYTIC DEWAXING WITH TRIVALENT RARE
EARTH METAL ION EXCHANGED FERRIERITE
BACKGROUND OF THE DISCLOSURE
Field of the Invention
The invention relates to catalytic dewaxing with a rare earth metal ion
exchanged
ferrierite. More particularly the invention relates to catalytically dewaxing
a waxy
hydrocarbonaceous feed to reduce its pour point, using a dewaxing catalyst
comprising
ferrierite in which one or more trivalent rare earth metals occupy at least a
portion of its
cation exchange positions.
Background of the Invention
Catalytically dewaxing waxy hydrocarbonaceous materials such as paraffinic
feeds to reduce their pour point and convert the wax to more useful products,
such as
fuel and lubricating oil fractions, is known. Such feeds have included
petroleum derived
wax containing oils, heavy oil fractions and slack wax. Dewaxing catalysts
comprise a
catalytic metal component, a natural or synthetic, crystalline aluminosilicate
or zeolite
molecular sieve component and often one or more additional refractory metal
oxide
components. Molecular sieves which have been found useful for dewaxing
petroleum
oil fractions and slack wax include, for example, ferrierite (U.S. Patents
4,343,692 and
4,795,623), mordenite (U.S. Patent 3,902,988), ZSM-23 and ZSM-35 (U.S. Patent
4,222,855), ZSM-5 and ZSM-11 (U. S. 4,347,121 ) and ZSM-5 (4,975,177).These
various catalysts have different selectivities for different products. For
example, while
ZSM-5 is particularly effective for dewaxing Tube oil raffinates, the cracking
selectivity
to gaseous products is high resulting in low Tube yield. There is still a need
for a
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dewaxing catalyst and process selective towards the production of lube oil
base stocks,
and particularly for premium, high purity and high VI Tube oils with low pour
points.
SUNEVIARY OF THE INVENTION
It has been found that ferrierite can be ion exchanged with trivalent rare
earth
metal using a hydrothermal ion exchange method and that a dewaxing catalyst
comprising the rare earth exchanged ferrierite exhibits better overall
selectivity for
producing Tube oil fractions having a low pour point and a high VI than the
hydrogen
form of either ferrierite or mordenite. Thus, the invention relates to a
process for
catalytically dewaxing a waxy hydrocarbonaceous material by reacting the
material with
hydrogen, in the presence of a catalyst comprising ferrierite in which at
least a portion,
preferably at least 10 %, more preferably at least 15 % and still more
preferably at least
25 % of its cation exchange capacity is occupied by one or more trivalent rare
earth
metal cations, under reaction conditions effective to reduce the pour point of
the
material. By rare earth metal is meant the lanthanide elements and includes
La, Ce, Pr,
Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y and mixtures thereof.
Hereinafter, in
the context of the invention "RE-ferrierite" is meant to include either
natural or synthetic
ferrierite in which at least a portion, preferably at least 10 %, more
preferably at least 15
and still more preferably at least 25 % of the cation exchange capacity is
occupied by
one or more of these trivalent lanthanide elements. When used for catalytic
dewaxing,
at least one catalytic metal component effective for catalytic dewaxing is
added to the
RE-ferrierite. Such metal components will typically include at least one Group
VIII
metal and preferably at least one Group VIII noble metal. Further, the RE-
ferrierite may
be composited with other known catalytic components which are described in
detail
below. A dewaxing catalyst comprising RE-ferrierite of the invention to which
has been
added a Group VIII noble metal has been found to be particularly effective for
producing high yields of dewaxed lubricating oil fractions of reduced pour
point from
Fischer-Tropsch wax that has been hydroisomerized to produce a mixture of iso-
paraffins and normal paraffins. Prior to being catalytically dewaxed,
hydrocarbon feeds
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derived from petroleum, shale oil, tar sands, and the like will be
hydrotreated to remove
sulfur and nitrogen compounds, aromatics and other unsaturates.
DETAILED DESCRIPTION
As set forth above, a typical dewaxing catalyst of the invention will comprise
RE-ferrierite and also at least one catalytic metal component. The dewaxing
catalyst of
the invention is a dual function catalyst having both a hydroisomerization and
a
dehydrogenation- /hydrogenation function, with the RE-ferrierite providing the
hydroisomerization function and the catalytic metal component the
dehydrogenation/
hydrogenation function. In one embodiment the catalyst will also contain one
or more
refractory catalyst support materials, including one or more additional
molecular sieve
components. The refractory catalytic support material may include, for
example, any
oxide or mixture of oxides such as silica which is not catalytically acidic
and acid oxides
such as silica-alumina, other zeolites, silica-alumina-phosphates, titania,
zirconia,
vanadia and other Group IIIB, IV, V or VI oxides. The Groups referred to
herein refer
to Groups as found in the Sargent-Welch Periodic Table of the Elements
copyrighted in
1968 by the Sargent-Welch Scientific Company. A catalytic metal component,
such as
one or more Group VIII metals and preferably at least one noble metal of Group
VIII,
may be deposited on, ion exchanged into or composited with the RE-fernerite or
it may
be supported on one or more refractory catalyst support materials or
additional
molecular sieve components that have been or will be composited or mixed with
the RE-
ferrierite. Thus, the catalytic metal, and promoter metal if present, is
composited or
mixed with, impregnated into, occluded or otherwise added to one or more of
the other
catalyst components either before or after they are all mixed together and
extruded or
pilled. In one embodiment it has been found to be effective to ion-exchange
the catalytic
metal (e.g., preferably a noble metal as Pt or Pd and preferably Pt) into the
ferrierite.
One or more metal promoter components of Groups VIB and VIIB may be used with
the one or more Group VIII metal catalytic components. Typical catalytic
dewaxing
conditions useful in the process of the invention are set forth in the Table
below.
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Condition Broad Preferred
Temperature, F 300-950 400-800
Total pressure, psig 250-3,000 500-1,500
LHSV 0.1-10 0.5-5
Hydrogen treat rate, SCF/B 500-15,0001,000-3,000
An RE-ferrierite dewaxing catalyst of the invention may be used to dewax any
waxy hydrocarbonaceous feed, including light and heavy petroleum oils, slack
wax,
Fischer-Tropsch wax and the like. Prior to being catalytically dewaxed,
hydrocarbon
feeds derived from petroleum, shale oil, tar sands, and the like will be
hydrotreated to
remove sulfur and nitrogen compounds, aromatics, and non-aromatic unsaturates.
It is
preferable to deoil such feeds prior to the hydrotreating to an oil content of
from about
0-35 wt. % and preferably 5-25 wt. %. The hydrotreating step is accomplished
by
reacting the feed with hydrogen in the presence of any well known
hydrotreating catalyst
at hydrotreating conditions. Such catalysts typically comprise catalytic metal
components of Co/Mo, Ni/Mo or Ni/Co/Mo on alumina and are well known to those
skilled in the art. Typical conditions include a temperature in the range of
from 540
750°F, a space velocity of 0.1 to 2.0 v/v/hr, a pressure of from 500-
3,000 psig and
hydrogen treat rates of from 500-5,000 SCF/B. Further, if desired the feed may
also be
hydroisomerized prior to catalytic dewaxing.
A dewaxing catalyst comprising the RE-ferrierite of the invention has been
found
to be particularly effective for producing dewaxed lubricating oil fractions
of low pour
point with high product yield from Fischer-Tropsch wax that has been
hydroisomerized
over a dual function catalyst to produce a heavy boiling feed comprising a
mixture of
iso-para~ns and normal para~ns. When produced via a slurry process from a
catalyst
which includes a cobalt catalytic component, this Fischer-Tropsch wax feed is
very pure,
typically having less than 1 wppm of either sulfur or nitrogen and comprising
at least 95
wt. % paraffins and even >_ 98-99 wt. % paraffns which may also contain very
minor
(e.g., less than 1 wt. %) amounts of olefins and oxygenates. A waxy feed of
this general
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composition and purity will ordinarily not require treatment prior to
hydroisomerization,
because any unsaturates and oxygenates which may be present are in such small
quantities that they will be consumed in the hydroisomerization without
adversely
effecting the hydroisomerization catalyst. However, there are other known
Fischer-
Tropsch hydrocarbon synthesis processes and catalysts which will not produce a
waxy
feed of this purity and which may, therefore, require hydrotreating prior to
hydroisomerization. By Fischer-Tropsch wax is generally meant the product of a
Fischer-Tropsch hydrocarbon synthesis process containing CS+, preferably CIO+
and
more preferably C2~ paraffnic hydrocarbons. In a slurry process, the wax
comprises
the hydrocarbon liquid withdrawn from the slurry reactor. For example, the
Table
below shows the fractional make-up (~ 10 wt. % for each fraction) of
hydrocarbons
synthesized in a slurry HCS reactor using a catalyst comprising cobalt and
rhenium on a
titania support.
Boiling Temperature Ranges,Wt. % of Fraction
F
IBP-320 13
320-500 23
500-700 19
700-1050 34
1050+ 11
Total 100
During hydroisomerization of the waxy, paraffinic feed in the process of the
invention, some of the heavy feed (e.g., 650°F+ to 750°F+),
depending on the desired
cut point and whether or not dewaxed fuel fractions are also desired, is
converted to
lower boiling components, with any olefins and oxygenates present being
hydrogenated.
Fuel fractions are generally dewaxed to reduce their cloud (or haze) and
freeze points.
Hydroisomerization conditions can vary widely. Broad ranges of temperature and
pressure are typically 300-900°F (149-482°C) and 0-2500 psig,
with preferred ranges of
550-750°F (288-400°C) and 300-1200 psig, respectively. The range
of hydrogen treat
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rates is typically 500-5000 SCFB and 50-500 SCFB, with preferred ranges of
2000-
4000 SCFB and SO-500 SCFB, respectively. The hydroisomerization catalyst
comprises one or more catalytic metal components supported on an acidic metal
oxide
support to give the catalyst both a hydrogenation/dehydrogenation function and
an acid
hydroisomerization function. Illustrative, but non-limiting examples of such
catalysts,
their preparation and use may be found, for example, in U.S. Patents 5,378,348
and
5,660,714. The isomerate is fractionated to separate the lighter 650°F-
to 750°F-
isomerate (depending on the desired cut point) from the heavier Tube oil
fraction, with
the lighter material used for fuel boiling in the naphtha and diesel fuel
ranges, if desired.
The Tube oil fraction is then catalytically dewaxed by reacting with hydrogen
using the
catalyst and process of the invention to further reduce its pour point.
Ferrierite is classified primarily as a medium pore size material having pore
windows of 5.40 x 4.20 (p. 106, Atlas of Zeolite Structure Types, 4'~ Ed.,
Elsevier
1996). Natural and synthetic ferrierite comprise a zeolite type of ion
exchangeable,
crystalline aluminosilicate molecular sieve having both ten and eight ring
pore windows,
with a silicon to aluminum atomic ratio of about five in natural fernerite
(although this
can vary) and a ratio of from about eight to greater than thirty (typically
from ten to
twenty) in synthetic ferrierite, as is known. The preparation and composition
of
synthetic ferrierite is well known and discussed, for example, in U.S. Patents
4,251,499
and 4,335,019. Both natural and synthetic fernerite are commercially available
in which
the cation exchange positions are typically occupied by alkali metal cations,
such as Na+,
K+ and mixtures thereof. The alkali form is readily converted to the hydrogen
form or
to a hydrogen precursor form, such as the ammonium ion form, for subsequent
ion
exchange with the desired metal(s), simply by contacting it with an aqueous
solution
containing ammonium ions which exchange with the alkali metal cations.
Calcination of
the ammonium form will produce the hydrogen (H+) or acid form, which can also
be
produced directly by contacting the ferrierite with a suitable material such
as
hydrochloric acid. While ferrierite both with and without a catalytic metal
component is
known as a dewaxing catalyst, examples of dewaxing using rare earth ion
exchanged
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ferrierite have not been disclosed. This is not surprising, since the
conventional ion
exchange technique is ineffective for this purpose. For example, U.S. Patents
4,584,286
and 5,288,475 which relate to ZSM-35, both refer to U.S. Patents 3,140, 249;
3,140,251 and 3,140,253 for conventional ion exchange techniques. The '249,
'251 and
'253 patents disclose metal ion exchange, including rare earth metal ion
exchange, using
aqueous salt solutions of the metal or metal and ammonia at atmospheric
pressure and a
temperature ranging from room temperature to 180°F. However, it has
been found that
this technique is not effective for ion exchanging rare earth metals with
ferrierite.
Furthermore, although rare earth metal ion exchange is included among a long
list of
potential cations, the surprising selectivity towards lube oil fractions
resulting from the
use of the trivalent rare earth exchanged ferrierite is no where mentioned.
For example,
using this technique to try to ion exchange lanthanum with ammonium ferrierite
from an
aqueous solution of lanthanum chloride at 180°F for 48 hours, followed
by washing with
water, resulted in a lanthanum content of only 0.31 wt. %. This means that at
maximum
only about 5 % of the cation exchange capacity was met by trivalent lanthanum
cations
in cation exchange positions. While not wishing to be held to any particular
theory, it is
believed that if ion exchange occurred, it may have occurred only on the
exterior surface
of the ferrierite and not in the pores where it is needed to be catalytically
effective.
Therefore, the present invention is unexpected in view of the prior art. In
the practice of
the invention, the trivalent rare earth metal or metals are ion exchanged into
the ferrierite
using a hydrothermal technique in which a hydrogen ferrierite precursor or
hydrogen
(H+) ferrierite is contacted with an aqueous solution of the desired trivalent
rare earth
metal or metals, under hydrothermal conditions, which means at a temperature
above the
normal atmospheric pressure boiling point of the solution. The time and
temperature
sufficient to achieve the desired level of exchange is determined
experimentally. For
example, ammonium ferrierite was immersed in a solution of lanthanum chloride
in
sealed vessel at a temperature of 392°F (200°C) for 24 hours and
yielded a lanthanum
exchanged ferrierite containing 1.97 wt. % La. This means that about 28 % of
the
cation exchange capacity available for cation exchange was occupied by
lanthanum. The
time and temperature sufficient to achieve the desired level of exchange is
determined
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experimentally. After ion exchange, the ion exchanged ferrierite may then be
washed,
dried, calcined and the ion exchange, washing, drying and calcining steps
repeated as
many times as needed to achieve the desired ion exchange level. As a practical
matter,
typically a mixture of two or more rare earth metals will be ion exchanged.
Illustrative
but non-limiting examples include commercially available mixtures of
lanthanum, cerium,
praseodymium and neodymium as the main rare earth metals in the mix. For
catalytic
use, the cerium content of the mix is typically depleted.
As mentioned above, the silica to alumina mole ratio or the silicon to
aluminum
mole ratio of ferrierite will vary. The cation exchange capacity of the
fernerite is
determined by the aluminum or alumina content. Each mole of aluminum ions
substituted in tetrahedral positions of the zeolite framework generates a mole
of
negative charge on the framework. This charge is balanced by exchangeable
cations.
Since rare earth metal (RE) cations are trivalent, each mole of RE ion
incorporated via
ion exchange replaces three moles of alkali metal, ammonium or hydrogen ions.
Therefore, the degree or percent of RE exchange which is a measure of cation
exchange
positions occupied by the trivalent rare earth cations is more meaningful than
the weight
percent of rare earth metal incorporated into the ferrierite after ion
exchange with
solutions containing one or more rare earth metal cations. The rare earth
metal (RE)
content, the Si02/A1203 mole ratio and the degree of exchange are all related
by the
expression:
RE exchange = [3 x (moles RE)] / [(moles Al) x 100]
These values are determined by any suitable analytical technique (such as
elemental
analysis) which yields the amount of each element present in the dry RE-
ferrierite
resulting after exchange and washing with water, to remove all metal that has
not been
ion exchanged. By way of example, the table below gives examples of the
content in wt.
of the rare earth metal La calculated on a dry basis with variation of the
Si02/A1203
mole ratio in the ferrierite and the % La exchanged. This shows that at high
Si02/A1203
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mole ratios of the ferrierite, elemental analysis will show low wt. % La even
at
substantial degrees of La exchange.
Si/Al Wt. % La
Si02/A12O3 at % La
Exchange
Shown
5 10 20 30
2.5 1.09 2.16 4.22 6.21
5 0.64 1.27 2.51 3.71
10 0.35 0.70 1.38 2.06
50 25 0.15 0.30 0.59 0.88
80 40 0.09 0.19 0.37 0.56
100 50 0.08 0.15 0.30 0.45
With specific regard to waxy feeds produced by a Fischer-Tropsch hydrocarbon
synthesis (HCS) process, liquid and gaseous hydrocarbon products are formed by
contacting a synthesis gas (syngas) comprising a mixture of H2 and CO with a
Fischer-
Tropsch type of HCS catalyst, in which the H2 and CO react to form
hydrocarbons
under shifting or non-shifting conditions and preferably under non-shifting
conditions in
which little or no water gas shift reaction occurs, particularly when the
catalytic metal
comprises Co, Ru or mixture thereof. Suitable Fischer-Tropsch reaction types
of
catalyst comprise, for example, one or more Group VIII catalytic metals such
as Fe, Ni,
Co, Ru and Re. In one embodiment the catalyst comprises catalytically
effective
amounts of Co and one or more of Re, Ru, Fe, Ni, Th, Zr, Hf, U, Mg and La on a
suitable inorganic support material, preferably one which comprises one or
more
refractory metal oxides. Preferred supports for Co containing catalysts
comprise
titanic, particularly when employing a slurry HCS process in which higher
molecular
weight, primarily paraffinic liquid hydrocarbon products are desired. Useful
catalysts
and their preparation are known and illustrative, but nonlimiting examples may
be found,
for example, in U.S. Patents 4,568,663; 4,663,305; 4,542,122; 4,621,072 and
5,545,674. Fixed bed, fluid bed and slurry hydrocarbon HCS processes are well
known
and documented in the literature. In all of these processes the syngas is
reacted in the
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presence of a suitable Fischer-Tropsch type of hydrocarbon synthesis catalyst,
at
reaction conditions effective to form hydrocarbons. Some of these hydrocarbons
will be
liquid, some solid (e.g., wax) and some gas at standard room temperature
conditions of
temperature and pressure of 25°C and one atmosphere. Slurry HCS
processes are often
preferred because of their superior heat (and mass) transfer characteristics
for the
strongly exothermic synthesis reaction and because they are able to produce
relatively
high molecular weight, paraf~nic hydrocarbons when using a cobalt catalyst.
Due to
sulfur and nitrogen compound removal from the syngas feed prior to the
synthesis
reaction, the purity of the hydrocarbons produced by the process employing
sulfur and
nitrogen sensitive catalysts is exceptionally high, typically requiring little
or no
hydrotreating prior to isomerization, catalytic dewaxing or other upgrading
operations.
In a slurry HCS process, which is a preferred process in the practice of the
invention, a
syngas comprising a mixture of H2 and CO is bubbled up as a third phase
through a
slurry in a reactor which comprises a particulate Fischer-Tropsch type
hydrocarbon
synthesis catalyst dispersed and suspended in a slurry liquid comprising
hydrocarbon
products of the synthesis reaction which are liquid at the reaction
conditions. The mole
ratio of the hydrogen to the carbon monoxide may broadly range from about 0.5
to 4,
but is more typically within the range of from about 0.7 to 2.75 and
preferably from
about 0.7 to 2.5. The stoichiometric mole ratio for a Fischer-Tropsch HCS
reaction is
2.0, but in the practice of the present invention it may be increased to
obtain the amount
of hydrogen desired from the syngas for other than the HCS reaction. In a
slurry HCS
process the mole ratio of the HZ to CO is typically about 2.1/1. Slurry HCS
process
conditions vary somewhat depending on the catalyst and desired products.
Typical
conditions effective to form hydrocarbons comprising mostly CS+ parafl-ins,
(e.g., CS+-
C2oo) and preferably Clo+ parafl'ins (and more preferably C2o+) in a slurry
HCS process
employing a catalyst comprising a supported cobalt component include, for
example,
temperatures, pressures and hourly gas space velocities in the range of from
about 320-
600°F, 80-600 psi and 100-40,000 V/hr/V, expressed as standard volumes
of the
gaseous CO and H2 mixture (0°C, 1 atm) per hour per volume of catalyst,
respectively.
The hydrocarbons which are liquid at the reaction conditions removed from the
reactor
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(using filtration means and, optionally a hot separator to recover Clo+ from
the HCS
gas) comprise mostly (e.g., > SO wt. % and typically 60 wt. % or more)
hydrocarbons
boiling over 650-700°F and comprise at least about 95 wt. % parafEns
with negligible
(e.g., less than 1 wppm) amounts of either nitrogen or sulfur compounds.
The invention will be further understood with reference to the examples below.
EXAMPLES
Example 1
Ammonium ion exchange of alkali metal ferrierite was performed by suspending
100 g of Na-ferrierite having a silicon to aluminum ratio of 8.4 in 500 ml of
a 5 wt.
aqueous NH4C1 solution. The mixture was stirred for several hours at
SO°C, filtered,
and washed with distilled and deionized water. The exchange was repeated twice
and
the resulting NH4-ferrierite was dried at 70°C in a vacuum oven.
Lanthanum ion
exchange with the NH4-ferrierite was achieved by sealing 7 g of NH4-ferrierite
and 40
ml of a 0.2 M aqueous solution of LaCl3 in a Teflon lined stainless steel
vessel, followed
by heating at 200°C for 24 hours with occasional shaking. The vessel
was quenched
with cold water and opened immediately. The solid was filtered, washed with
hot
distilled and deionized water until chloride free according to an AgN03 test
and then
dried at 70°C in a vacuum oven. Elemental analysis of the NH4-
ferrierite and the La-
ferrierite gave Si/Al atomic ratios of 8.1 in both cases. The La-ferrierite
contained 1.86
wt. % La, indicating 27 % of the available cation exchange positions were
occupied by
the lanthanum. Refinement of X-ray powder diffraction data gave orthorhombic
cell
constants of 18.84, 14.10 and 7.43 ~ for the NH4-ferrierite and 18.94, 14.12
and 7.45 0
for the La-ferrierite. The BET surface area of the NH4-ferrierite was 288 m2/g
and that
of the La-ferrierite was 320 m2/g.
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Comparative Example A
A 0.4 g sample of the NH4-ferrierite prepared in Example 1 was mixed with 2.4
g of a 5 wt. % aqueous solution of LaCl3 in a capped vial and heated to
180°F for 48
hours with occasional shaking. The resulting material was separated from the
solution
by filtration, washed with distilled and deionized water until chloride-free
by an AgN03
test and then dried in a vacuum oven at 70°C. Elemental analysis
revealed a lanthanum
content of only 0.31 %, indicating that only about S % of the available cation
exchange
positions may have been occupied by lanthanum.
Example 2
Dewaxing catalysts were prepared by adding 0.5 wt. % platinum to both the
NHS-ferrierite and the La-ferrierite prepared in Example 1. The Pt was added
by ion
exchange with the remaining ammonium sites on the ferrierite using
Pt(NH3)4(OH)2.
These platinum loaded materials were then calcined in air at 400°C,
pilled, crushed and
screened to 14/35 Tyler mesh size. Elemental analysis revealed Pt contents of
0.57 and
0.54 wt. %, respectively.
Comparative Example B
An additional catalyst for comparative purposes was prepared by impregnation
and extrusion comprising 0.5 wt. %Pt supported on a mixture of 80 wt. %
mordenite
and 20 wt. % alumina which was calcined in air at 400°C.
Example 3
A hydrocarbon synthesis gas comprising a mixture of H2 and CO having a mole
ratio of between 2.11-2.16 was reacted in a slurry comprising bubbles of the
synthesis
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gas and particles of a Fischer-Tropsch hydrocarbon synthesis catalyst
comprising cobalt
and rhenium supported on titania in a hydrocarbon slurry liquid containing the
particulate catalyst and bubbles of the synthesis gas. The hydrocarbon slurry
liquid
comprised hydrocarbon products of the synthesis reaction which were liquid at
the
reaction conditions. The reaction conditions included a temperature of
425°F, a
pressure of 290 psig and a gas feed linear velocity of from 12 to 18 cm/sec.
The alpha
of the synthesis step was 0.92. A 700°F+ boiling fraction was separated
from the
hydrocarbon product by flash distillation.
Example 4
The synthesized, 700°F+ boiling hydrocarbon fraction from Example
3
comprised at least about 98 wt. % paraffins. This material was hydroisomerized
by
reacting it with hydrogen in the presence of a dual function
hydroisomerization catalyst
consisting of cobalt and molybdenum impregnated on an amorphous silica-alumina
support. The reaction and reaction conditions were adjusted to achieve 50 wt.
conversion of the 700°F+ material to lower boiling material and
included a temperature
of 700°F, a space velocity of 0.45 v/v/hr, a pressure of 1000 psig and
a hydrogen treat
rate of 2500 SCFB. The resulting isomerate was fractionated to recover the
700°F+
boiling fraction which comprised a mixture of normal
para~ns and isoparaffins and had a pour point of 2°C.
Exam 1p a 5
The dewaxing activity and selectivity of the three different catalysts
prepared in
Example 2 and in Comparative Example B was evaluated by reacting separate
portions
of the 700°F+ isomerate fraction of Example 4 with hydrogen in the
presence of each
catalyst using an upflow, 3/8 inch fixed bed reactor at reaction conditions of
750 psig,
2.0 w/h/w and a hydrogen treat rate of 2500 SCFB. The reaction temperature
varied
and was adjusted to achieve comparable Tube product pour point for each
catalyst. The
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results of these evaluations in terms of products and properties are shown in
the Table
below.
Pt/Nl~-ferrieritePt/L,a-ferrieritePtJH-mordenite
-alumina
Reactor Temp., F 635 635 518
Gas (C,-C4) 2.8 1.9 -
Naphtha (CS-320F) 3.4 1.7 -
Diesel (320-700F) 16.5 12.6 -
Lubes (700F+) 78.3 84.5 59.4
Lubes Pour Point, -32 -31 -30
C
Lubes VI 142 144 145
As these data show, the Pt/La-ferrierite catalyst was more selective towards
producing the dewaxed 700°F+ boiling tubes product than the Pt/NH4-
ferrierite, with
less gas make and higher tube yield at equivalent pour point. The Pt-mordenite
catalyst
produced significantly less 700°F+ material, with substantially more
gas make than the
Pt/La-ferrierite catalyst of the invention.
It is understood that various other embodiments and modifications in the
practice
of the invention will be apparent to, and can be readily made by, those
skilled in the art
without departing from the scope and spirit of the invention described above.
Accordingly, it is not intended that the scope of the claims appended hereto
be limited to
the exact description set forth above, but rather that the claims be construed
as
encompassing all of the features of patentable novelty which reside in the
present
invention, including all the features and embodiments which would be treated
as
equivalents thereof by those skilled in the art to which the invention
pertains.
