Note: Descriptions are shown in the official language in which they were submitted.
WO 94/25157 PCT/US94/04394
1
A METHOD OF TREATING SPONTANEOUSLY COMBUSTIBLE CATALYSTS
This invention relates to a method of treating
spontaneously combustible catalysts and catalyst compositions
resulting from such treatment. In one aspect, the invention
relates to a process for preparing catalysts that produces
catalyst compositions with reduced self-heating characteristics.
In another aspect, the invention relates to hydrotreating and/or
hydrocracking processes.
A spontaneously combustible catalyst is any catalyst
composition which has a tendency to self-heat or combust in the
presence of air or oxygen at a temperature of 200°C or lower.
Particularly, many hydrocarbon processing catalysts, such as
hydrotreating, hydrocracking and tail-gas treating catalysts
which typically contain sulfur and reduced catalysts such as
hydrogenation catalysts can be classified as spontaneously
combustible catalysts. Some of the hydrocarbon processing
catalysts can also be reduced catalysts.
A hydrotreating catalyst is used to catalyze the
hydrogenation of hydrocarbon feedstocks, and most particularly
to hydrogenate particular components of the feedstock, such as
sulfur-, nitrogen- and metals-containing organo-compounds and
unsaturates . A hydrocracking catalyst is used to crack large and
complex petroleum derived molecules to attain smaller molecules
with the concomitant addition of hydrogen to the molecules . Such
hydrocracking catalyst includes catalysts used for residue
conversion units. A tail gas catalyst is used to catalyze the
conversion of hazardous effluent gas streams to less harmful
products, and most particularly to convert oxides of sulfur to
hydrogen sulfide which can be recovered and readily converted
to elemental sulfur. A reduced catalyst is any catalyst that
contains a metal in the reduced state such as an olefin
hydrogenation
S~JBSTiTUTE SHEET (RULE 26)
WO 94/25157 PCTIUS94/04394
2
catalyst. ~uch metals are typically reduced with a reducing
agent such as hydrogen or formic acid. The metals on these
reduced catalyst may be fully reduced or partially reduced.
Hydrogenation catalysts are well known and several are
commercially available. Typically, the active phase of the
catalyst is based on at least one metal of group VIII, VIB, IVB,
IIB or IB of the periodic table, typically Pt, Pd, Ru, Ir, Rh,
Os, Fe, Co, Ni, Cu, Mo, W, Ti Hg, Ag or Au, usually supported
on a support such as alumina, silica, silica-alumina or carbon.
Such reduced catalysts can be spon-taneously combustible.
Catalyst compositions for hydrotreating and/or
hydrocracking or tail gas treating are well known and several
are commercially available, in particular metal oxide catalysts
including cobalt-molybdenum, nickel-tungsten, and nickel-
molybdenum, usually supported on alumina, silica and/or silica-
alumina, including zeolites and carriers. Other transition metal
element catalysts may be employed for these purposes, including
those containing at least one of V, Cr, Mn, Re, Co, Ni, Cu, Zn,
Mo, W, Rh, Ru, Os, Ir, Pd, Pt, Ag, Au, Cd, Sn, Sb, Bi and Te.
For maximum effectiveness the metal oxide catalysts are
converted at least in part to metal sulfides. The metal oxide
catalysts can be sulfided in the reactor by contact at elevated
temperatures with hydrogen sulfide or a sulfur-containing oil
or feed stock ("in-situ").
However, it is advantageous to the user to be supplied with
metal oxide catalysts having sulfur, as an element or in the
form of an organo-sulfur compound, incor-porated therein. These
presulfurized catalysts can be loaded into a reactor and brought
up to reaction conditions in the presence of hydrogen causing
the sulfur or sulfur compound to react with hydrogen and the
metal oxides thereby con-verting them into sulfides without any
additional process steps. These presulfurized catalysts provide
an economic advantage and avoid many of the hazards such as
flammability and toxicity, which the plant operator encounter
when using hydrogen sulfide, liquid sulfides, polysulfides
and/or mercaptans to sulfide the catalysts.
SUBSTITUTE Si~EET (RULE 26~
3
Several methods of presulfurizing metal oxide catalysts
are known. Hydrotreating catalysts have been presulfurized by
incorporating sulfur compounds into a porous catalyst prior to
hydrotreating a hydrocarbon feedstock, using, for example,
organic polysulfides, or elemental sulfur in which case
hydrogen is used as a reducing agent to convert the elemental
sulfur to hydrogen sulfide in situ. U.S.-A-4,943,547 discloses
subliming elemental sulfur into the pores of the catalyst then
heating the sulfur-catalyst mixture to a temperature above the
melting point of sulfur in the presence of hydrogen which
activates the catalysts. WO-A-93/02793 discloses a method
where elemental sulfur is incorporated in a porous catalyst and
at the same time or subsequently the catalyst is treated with a
liquid olefinic hydrocarbon.
However, these ex-situ presulfurized catalysts, which are
spontaneously combustible and may be pyrophoric or self-
heating, these two groups differing in the degree of
spontaneous combustion, must be transported to the user or
plant operator. Pyrophoric substances ignite, even in small
quantities, within five minutes of coming into contact with air
whereas self-heating substances ignite in air only when in
large quantities and after long periods of time. Pyrophoric
substances are typically classified as Division 4.2 Packing
Group I and self-heating substances are classified in either
Packing Group II or Packing Group III according to the test
procedures recommended in the Dangerous Goods Special Bulletin,
April 1987, published by TDG Ottawa, Transport Canada for Class
4, Division 4.2. These spontaneously combustible substances
must be packaged in a United Nations designated 250 kg metal
drum or in a smaller package of 100 kg plastic fibre drum or
even smaller.
It is clearly desirable to transport these presulfurized
catalysts in larger quantities such as in flow bins or super-
sacks but they must pass the test for spontaneously combustible
substances.
EP-A-447,221 discloses a method of presulfiding a
hydrotreating or hydrocracking catalyst which minimises
stripping upon start-up of a hydrotreating or hydrocracking
reactor utilizing such a catalyst.
AM~t~E~D SH~~T
T
CA 02162127 2004-O1-23
-4-
Further, some of the prior art ex-situ methods of
presulfurizing supported metal oxide catalysts have
suffered from excessive stripping of sulfur upon start-up
of a hydrotreating reactor in the presence of a
hydrocarbon feedstock. As a result decrease in catalyst
activity or stability is observed and there can be
fouling of downstream equipment.
Therefore, it is an object of the present invention
to treat spontaneously combustible catalysts in a manner
to suppress their self-heating properties.
The present invention provides a composition
comprising a presulfurized or sulfided catalyst which is
supported on a porous support, at least a part of which
catalyst has been coated and/or impregnated with at least
one oxygen-containing hydrocarbon having at least 16
carbon atoms and having an iodine value of at least 60,
with the proviso that when the hydrocarbon is a fatty
acid triglyceride the catalyst has not been coated and/or
impregnated with the hydrocarbon prior to or at the same
time as the catalyst is presulfurized or sulfided and the
coated and/or impregnated catalyst has been heat treated
in the absence of added hydrogen at a temperature of at
least 175°C, thereby reducing the self-heating
characteristics of said catalyst. The coating and/or
impregnation can be achieved by contacting the catalyst
with the oxygen-containing hydrocarbon at a temperature
of at least 0°C. Such composition has a reduced self-
heating characteristic when compared to the spontaneously
combustible catalyst which has not been coated.
Further, the present invention provides a method of
oeducing the self-heating characteristics of a
~~resulfurized or sulfided catalyst which has a tendency
t.o self-heat or combust in the presence of air or oxygen
CA 02162127 2004-O1-23
-5-
at a temperature of 200°C or lower and which catalyst is
supported on a porous support, which comprises contacting
said catalyst with at least one oxygen-containing
hydrocarbon having at least 16 carbon atoms and having an
iodine value of at least 60, with the proviso that when
the hydrocarbon is a fatty acid triglyceride the catalyst
has not been coated and/or impregnated with the
hydrocarbon prior to or at the same time as the catalyst
is presulfurized or sulfided.
When the catalyst is a sulfidable metal or metal
oxide(s)-containing catalyst, the method may comprise
presulfurizing the catalyst by:
(a) contacting said catalyst with elemental sulfur,
a sulfur compound or a mixture thereof at a temperature
such that at least a portion of said sulfur or sulfur
compound is incorporated in the pores of said catalyst by
impregnation, sublimation and/or melting; and
(b) prior to, at the same time or subsequently
contacting said catalyst particles in the presence of an
oxygen-containing hydrocarbon having at least 16 carbon
atoms.
The present invention also provides a process for
preparing a catalyst suitable for hydrotreating and/or
hydrocracking a hydrocarbon stream or tail gas treating a
sulfur-containing gas stream, which comprises heating a
presulfurized composition of the invention to 200°C to
500°C in the presence of hydrogen to produce metal
sulfide.
The present invention also provides a process for
hydrotreating and/or hydrocracking a hydrocarbon stream
or tail gas treating sulfur-containing gas stream which
comprises contacting the stream in the presence of
hydrogen with a sulfided catalyst of the invention
CA 02162127 2004-O1-23
-5a-
wherein the catalyst is a reduced catalyst, a
hydrocracking catalyst or a hydrotreating catalyst or one
prepared by heating a presulfurized composition of the
invention to 200°C to 500°C in the presence of hydrogen
to produce metal sulfide.
The present invention also provides a method of
transporting a presulfurized or sulfided catalyst which
has a tendency to self-heat or combust in the presence of
air or oxygen at a temperature of 200°C or lower and
which catalyst is supported on a porous support, which
comprises carrying out the method of reducing self-
heating characteristics of the invention, placing the
treated catalyst in a container and then transporting the
container.
The present invention also provides a method of
unloading a presulfurized or sulfided catalyst which has
a tendency to self-heat or combust in the presence of air
or oxygen at a temperature of 200°C or lower and which
catalyst is supported on a porous support, from a reactor
in operation which comprises stopping reactor operation,
carrying out the method of reducing self-heating
characteristics of the invention and then removing the
oxygen-containing hydrocarbon treated catalyst from the
reactor.
It has been found that by treating a spontaneously
combustible catalyst by contacting with an oxygen-
containing hydrocarbon having at least 16 carbon atoms,
the resulting catalyst has suppressed self-heating
characteristics, in general, such that it is no longer
classified as spontaneously combustible. Thus, the
process allows an otherwise spontaneously combustible
catalyst to be transported or shipped in any suitable
packaging such as flow-bins, super-sacks, or sling-bins
CA 02162127 2004-O1-23
-5b-
for example.
As used herein, a "spontaneously combustible
catalyst(s)" is any heterogeneous or solid metal(s)-,
metal oxide(s)-, metal sulfide(s)- or other metal
compound(s)- containing catalyst, which is on a support
which can be classified as a spontaneously combustible
substance according to the test procedures recommended in
the Dangerous Goods Special Bulletin, April 1987,
published by TDG Ottawa, Transport Canada for Class 4,
Division 4.2 or has an onset of exotherm below 200°C as
measured by the self-heating ramp test described below.
The terms "metal(s)-", "metal oxide(s)-" and "metal
sulfide(s)-" containing catalysts include catalyst
precursors that can be used as catalysts after further
treatment or activation. Further the term "metal(s)"
includes metals) in partially oxidized form. The term
"metal oxide(s)" includes metal oxides) in partially
reduced form. The term "metal sulfide(s)" includes metal
sulfides) that are partially sulfided as well as totally
sulfided metals.
It is understood that while the normal catalyst
preparative techniques will produce metal oxide(s), it is
possible to utilize special preparative techniques to
produce the catalytic metals in a reduced form, such as
the zero valent state. Since metals in the zero valent
state will be sulfided as well as the oxides when
subjected to sulfiding conditions, catalysts containing
such sulfidable metals even in reduced or zero valent
states will be considered as "sulfidable metal oxide
catalysts)". Also the process of the instant invention
can be applied to regenerated catalysts which may have
the metal sulfide not completely converted to the oxides.
Other components such as carbides, borides,
CA 02162127 2004-O1-23
-5c-
nitrides, oxyhalides, alkoxides and alcoholates can also
be present.
In one embodiment of the present invention, a
presulfurized or sulfided catalyst which has a tendency
to self-heat or combust in the presence of air or oxygen
at a temperature of 200°C or lower and which catalyst is
supported on a porous support, is contacted with at least
one
2~sz~z~
oxygen-containing hydrocarbon at a temperature of at least
about 0°C, preferably at least 15°C to 350°C, and more
preferably 20°C to 150°C. Upon contact, the oxygen-containing
hydrocarbon is impregnated into the catalyst so that the
surface~of the catalyst is coated with the oxygen-containing
hydrocarbon. For the purpose of definition, the surface of the
catalyst includes the external surface of the catalyst as well
as the internal pore surfaces of the catalyst. The word
"coating" does not rule out some reaction as defined below.
The mechanism by which the oxygen-containing hydrocarbon
suppresses the self-heating characteristics of the spontane-
ously combustible catalysts is not known and will be referred
to, for convenience as "reaction" or "reacts". The suppressed
self-heating result can be readily determined without undue
experimentation by measuring the exothermic onset temperatures
for a specific rising temperature profile of catalysts sub-
jected to differing temperature/time treatments with and with-
out the oxygen-containing hydrocarbon, as shown below.
When sulfur-containing catalysts are treated their sulfur
retention or activity is not substantially compromised. The
sulfided catalysts can be catalysts sulfided by an in-situ
presulfiding method or an ex-situ presulfiding or presulfuri
zing method. Such catalysts can be fresh or oxy-regenerated, for
example, those disclosed in U.S.-A-4,530,917; 4,177,136;
4,089,930; 5,153,163; 5,139,983; 5,169,819; 4,530,917 or
4,943,547 or WO-A-93/02793, or reduced hydrogenation catalyst
such as disclosed in U.S. Patent No. 5,032,565.
The treatment can also be applied prior to, at the same
time or subsequent to presulfurizing a presulfidable metal or
metal oxide catalyst. Preferably the catalyst is heated after
contacting with elemental sulfur or a sulfur compound at an
elevated temperature and time sufficient to fix the sulfur onto
the catalyst. Such heating process can be before or after
treatment with the oxygen-containing hydrocarbon.
Generally, the catalysts of the present invention also
have enhanced resistance to sulfur stripping during startup in
a
' ~~l?t~I fI~
WO 94/25157 2 ~ 6 21 2 7 PCT/US94/04394
7
hydrotreating and/or hydrocracking reactor in the presence of
a hydrocarbon feedstock. The mechanism by which this occurs is
not known and will be referred to for convenience as "reaction"
or "reacts" . A suitable method for determining sulfur stripping
resistance is described below wherein toluene is used as
stripping agent.
Further, for reasons unknown for elemental sulfur
incorporated catalysts, the percent retention of sulfur is
generally improved by the treatment, particularly for some high
pore volume catalysts.
There are three general methods for carrying out the
presulfurising process.
In the first method porous catalyst particles are contac
ted with elemental sulfur or sulfur compounds or mixtures
thereof so as to cause the sulfur or sulfur compounds to be
incorporated into the pores of the catalyst by impregnation, by
sublimation, by melting or by a combination thereof to produce
"sulfur-incorporated catalysts."
The sulfur-incorporated catalyst particles are contacted
with the oxygen-containing hydrocarbon at temperatures and times
sufficient to cause the catalyst particles to exhibit suppressed
self-heating properties.
When using elemental sulfur, the catalyst is contacted at
a temperature such that the elemental sulfur is substantially
incorporated in the pores of the catalyst by sublimation and/or
melting. While the catalyst particles can be contacted with
sulfur in the molten state, it is preferred to first admix the
catalyst particles with powdered elemental sulfur and then heat
the mixture to above the temperature at which sublimation of the
3 0 sulfur occurs .
Generally the catalyst particles are heated in the presence
of the powdered elemental sulfur at a temperature greater than
about 80°C. Typically the catalyst and powdered sulfur are
placed in a vibratory or rotary mixer and heated to the desired
temperature for sufficient time, typically 0.1 to 10 hours or
more, to allow for the incorporation.
SUBSTITUTE SHEET tRUIE 26)
WO 94/25157 LT/US94/04394
G 8
~1.~~~_ z~
Preferably the sulfur impregnation step is carried out at
90°C to 130°C or higher, up to the boiling point of sulfur
(about 445°C). The lower temperature limit is fixed by the
sublimation/melting characteristics of sulfur under the specific
conditions of impregnation, whereas the upper temperature limit
is fixed primarily by economics, higher temperatures being more
costly to produce as well as more difficult to work with.
The sulfur-incorporated catalyst is then treated with the
oxygen-containing hydrocarbon, as discussed below.
The sulfur-incorporated catalyst may be further heated
before and/or after the oxygen-containing hydrocarbon treatment
at a temperature greater than about 150 ° C, preferably from 175
° C
to 350°C and more preferably from 200°C to 325°C, to fix
the
incorporated-sulfur onto the catalyst.
Preferred sulfur compounds include, for example, ammonium
sulfide, organic mono-, di- and poly-sulfides, dialkyl sulf-
oxides and compounds derived from these upon heating or reduc-
tion in the presence of the sulfidable metal oxide and mixtures
thereof. Examples of organic sulfides include poly-sulfides of
general formula R-S(n)-R' or HO-R-S(n)-R-OH wherein n is an
integer from 3 to 20 and R and R' are independently organic
radicals of 1 to 50 carbon atoms such as ditert dodecyl
polysulfide and diethanol disulfide; mercaptoalcohols such as
2-mercaptoethanol;.alkylmercaptans such as n-butyl mercaptan;
thioglycols such as dithiopropyleneglycol; dialkyl or diaryl
sulfides such as di-n-butyl sulfides and Biphenyl sulfides;
dialkylsulfoxides such as dimethyl sulfoxide; and mixtures
thereof .
Before use, the sulfur compounds are typically impregnated
3o with an aqueous or organic solution such as a hydrocarbon or
non-hydrocarbon equivalent to light gasoline, hexane or gasoline
of white spirit type, for example as described in U.S.-A
5,153,163; 5,139,983; 5,169,819; and 4,530,917. The resulting
catalysts are typically reduced by hydrogen, or other organic
reducing agent such as formic acid, methyl formate, ethyl
formate, acetaldehyde or methyl alcohol. The sulfur compound-
incorporated catalyst can be treated with the oxygen-containing
SUBST6TUTE SHEET (RULE 25;
WO 94125157 PCT/US94/04394
2162127
hydrocarbon before and/or after the reduction step under
conditions described above for the elemental sulfur-incorporated
catalyst.
In the second method, a porous sulfidable metal oxide
s containing catalyst is contacted with a mixture of powdered
elemental sulfur and/or a sulfur compound and the oxygen
containing hydrocarbon, preferably while heating the resultant
mixture to a temperature above about 80°C.
In this embodiment, the catalyst particles are contacted
with the elemental sulfur, preferably powdered, and/or at least
one sulfur compound and the oxygen-containing hydro-carbon
simultaneously. Other hydrocarbons such as olefins can be
optionally added simultaneously. A mixture of powdered ele
mental sulfur and/or sulfur compound and oxygen-containing hy
drocarbon is first produced. When elemental sulfur is used, the
ratio of hydrocarbon to sulfur by weight is typically from 1:2
to 30:1, preferably from 1:1 to 6:1. The mixture may be heated
to promote homogeneity, particularly if the hydrocarbon is not
liquid at ambient conditions or the mixture may be a suspension.
Toluene or other light weight hydrocarbon solvents may be added
to decrease the viscosity of the mixture. Increased heat will
achieve the same effect. When a sulfur compound is used as the
source of sulfur, the ratio of hydrocarbon to sulfur compound
by weight is typically from 1:2 to 30:1. The mixture is then
added to a preweighed catalyst sample and mixed. When a mixture
of elemental sulfur and sulfur compound is used as the source
of sulfur, a ratio of hydrocarbon to total sulfur and by weight
from 1:2 to 30:1 is suitable.
When, elemental sulfur is at least partially used, the
mixture is then heated to incorporate sulfur at a temperature
of above about 80°C. The times and temperature can be the same
as in for the first embodiment. When sulfur compounds are used
the catalyst can be reduced as above for the first embodiment.
In the third method, a porous sulfidable metal oxide
containing catalyst is first contacted with the oxygen
containing hydrocarbon before the presulfurization step. The
resultant mixture can be optionally heated to a temperature
above about room
SUBSTaTUTE SHEET (RULE 26)
WO 94/25157 PCT/US94104394
temperature (i.e. about 25°C) for a solid or semi-solid
hydrocarbon to allow it to impregnate the catalyst. The catalyst
and/or oxygen-containing hydrocarbon is preferably heated to at
least a temperature where the hydrocarbon becomes liquid or
5 semi-fluid. The hydrocarbon treated catalyst is then
presulfurized by contacting with elemental sulfur and/or sulfur
compound as described for the first method. Optionally, the
hydrocarbon-treated presulfurized catalyst can be heated during
the sulfurization step or after impregnation of sulfur compounds
10 regardless of prior heat-treatment. The catalyst should
preferably be heated at some point after contacting with the
sulfur at a temperature above about 150°C so as to fix the
sulfur on the catalyst.
The catalyst is preferably treated with the oxygen
containing hydrocarbon after sulfur and/or sulfur compound
incorporation for superior suppression of self-heating
characteristics. If the sulfur and/or sulfur compound and the
hydrocarbon are contacted with the metal or metal oxides)
catalyst simultaneously, it is preferable that the catalyst is
contacted in such a manner which allows the sulfur and/or sulfur
compounds to be incorporated or impregnated into the pores of
the catalyst prior to the catalyst reacting or being coated with
the hydrocarbon at a temperature of above 80°C.
In any of the above methods the amounts of sulfur or sulfur
compounds used will depend upon the amounts of catalytic metal
present in the catalyst. Typically the amount used is determined
on the basis of the stoichiometric amount of sulfur or sulfur
compounds required to convert all of the metal on the catalyst
to the sulfide form. For example a catalyst containing
molybdenum would require two moles of sulfur or mono-sulfur
compounds to convert each mole of molybdenum to molybdenum
disulfide. On regenerated catalysts, existing sulfur levels may
be factored into the calculations for the amounts of elemental
sulfur required.
It has been found that the addition of presulfurizing
sulfur in amounts down to about 50 percent of the stoichiometric
SUBSTITJTE SHEET ~~UL.E 26)
CA 02162127 2004-O1-23
11
requirement results in catalysts having enhanced hydrode~
nitrification activity, which is an important property of
hydrotreating and first stage hydrocracking catalysts. Thus, the
amount of presulfurizing sulfur used for incorporation into the
catalyst will typically be from 0.2 to 1.5 times, and preferably
from about 0.4 to about 1.2 times the stoichiometric amount.
For hydrotreating/hydrocracking and tail gas treating
catalysts containing Group VIB and/or Group VIII metals the
amount of presulfurizing sulfur employed is typically 2% to 15%,
and most preferably, 6% to l2%, by weight of the catalyst
charged. It is preferred not to add so much sulfur or sulfur
compound to the catalyst that the pores are completely filled
up. By leaving residual pore volume, the oxygen-containing
hydrocarbon can penetrate the pores and react therein.
The key step in the present invention is to contact the
catalyst with an oxygen-containing hydrocarbon having at least
16 carbon atoms for a sufficient time such that the hydrocarbon
impregnates {or reacts) with the catalyst and provides a
cat;~lyst that is less spontaneously combustible and, far a
sulfurised catalyst, is more resistant to sulfur leaching than
one not contacted with the hydrocarbon. Typically the contact
temperature is greater than about 0°C, desirably from 15°C to
350°C, preferably from 20°C to about 150°C. The contact
temperature will vary depending on the melting point or
sublimation temperature of the hydrocarbon. For example; when
the oxygen-containing hydrocarbon is a solid or a semi-solid, the
temperature should preferably be at least as high as the melting
point for a time sufficient for the catalyst to flow freely
appear "dry" and not stick or clump) , i . a . it is liquid or semi-
fluid, to enable the hydrocarbon to coat and/or impregnate the
catalyst. The process temperature can be readily determined by
the melting point of the solid or semi-solid at a given pressure
environment or visually by checking if the oxygen-containing
hydrocarbon flows. Contact times will depend on temperature and
the viscosity of the oxygen-containing hydrocarbon, higher
CA 02162127 2004-O1-23
12
temperatures requiring shorter times and higher viscosity
requiring longer times. In general times will range from 2
minutes to 2 hours or more.
Preferably the oxygen-containing hydrocarbon is suffi
ciently flowable or sublimable to give sufficient contact with
the catalyst. A hydrocarbon which is liquid at the elevated
temperature of contact is more preferred for ease of handling.
The hydrocarbon has at least sixteen, preferably greater than
sixteen, and more preferably greater than twenty carbon atoms.
The upper carbon number is determined by the melting. point,
solidification point, or smoke point of the hydrocarbon in
question. While solid fatty.oxygen-containing hydrocarbon having
carbon numbers greater than 100 can be used, they are inconven-
15- ient since they must be heated to such a high temperature in
order to be converted into a liquid, although they can be used
with a solvent. Hydrocarbons with carbon numbers from 16 to 100,
preferably from 16 to 80 are found most useful.
The term "oxygen-containing hydrocarbon" as used herein
refers to hydrocarbon molecules containing at least one oxygen
atom, which includes, for example, acids, acid esters, alcohols,
aldehydes, ketones and ethers. Mixtures may be used such as acid
esters and alcohols, and different acid esters. It can be
primary, secondary or tertiary, straight or branched chain,
cyclic, acyclic or aromatic. The hydrocarbon moiety contains at
least some unsaturation for superior activity as a hydrotreating,
hydrocracking or tail gas treating catalyst, typically an
unsaturated fatty acid ester. The term "unsaturated" as used
herein refers to hydrocarbon molecules containing at least one
carbon-carbon double bond or compounds) containing some carbon-
carbon double bond and will have an iodine value of at least 60
measured by standard iodine measuring techniques such as
American Oil Chemist Society (AOCS) Official Method Cd 1-25 or
IUPAC Method 2.205 described in International Union of Pure and
Applied Chemistry, 7th ed., Blackwell Scientif is Publications
1987 or any other standard iodine measuring techniques. The term
CA 02162127 2004-O1-23
13
~~saturated~~ as used herein refers to oxygen-containing
hydrocarbon compounds containing no carbon-carbon double bonds
or compounds) containing minimal carbon-carbon double bonds and
have a iodine value of less than 60 measured by AOCS Official
Method Cd 1-25, IUPAC Method 2.205 or any other standard~iodine
measuring techniques.
Preferred hydrocarbons include those having at least 16,
preferably 20 carbon atoms for example, higher alcohols such as
farnesol, hexestrol and oleyl alcohol; higher ethers; higher
ketones; higher aldehydes such as olealdehyde; unsaturated higher
acids such as palmitoleic, oleic, linoleic, linolenic,
eleostearic, ricinoleic, eicosenoic, docosenoic,
eicosatetraenoic, eicosapentaenoic, decosapentaenoic, and
docosahexaenoic; higher acids esters including mono-, di-, tri-
and poly-fatty acid esters alkyl and aryl esters of the above
acids (e.g. benzyl oleate and butyl oleate) and esters of the
dove acids with mono-glycerides, di-glycerides and triglycerides
and mixtures thereof. Glyceride fatty acid esters having from
16 to 100, more preferably 18 to 90, most preferably 20 to 80
carbon atoms are preferred.
Examples of commercial glyceride fatty acid esters include
soybean oil, linseed oil, safflower oil, corn oil, sunflower oil,
cottonseed oil, olive oil, tung oil, castor oil, rapeseed oil,
tall oil , peanut oil , canbra oil , perilla oil , marine fat or oil
such as fish fat or oil (e. g. herring and sardine), vegetable
residues and mixtures thereof. Higher oligomers and polymers of
polyols such as alkylene glycols are also suitable as higher
alcohols.
CA 02162127 2004-O1-23
14
optionally, the oxygen-containing hydrocarbon treated
catalyst can be further treated with or simultaneously treated
with, or treated prior to the hydrocarbon treatment with olefins
to enhance catalytic activity in hydrocracking, hydrotreating
or tail gas treating. The term "olefin" as used herein refer
to hydrocarbons containing at least one carbon-carbon double
bond. The olefins may be monoolefins or polyolefins, cyclic or
acyclic, linear or branched. Suitable monoolefins include
decene, undecene, dodecene, tridecene, tetradecene, pentadecene,
hexadecene, heptadecene, octadecene, nonadecene and e~osene,
whether branched, linear or cyclic, alpha or internal olefin.
Similar materials in the form of di-, tri- and polyolefins may
be used. Polycyclic olefins and polyolefins may also be used.
Dicyclopentadiene is found useful. The oxygen-containing
hydrocarbons may also be mixed with other hydrocarbons, such as
alkanes or aromatic solvents.
In general, for superior activity of the catalyst upon
start-up in the plant, the weight percent of the unsaturated
compounds of any hydrocarbon used in the process (including
unsaturated oxygen-containing hydrocarbon and olefin) should be
above about 5%wt., preferably above about 10%wt., and most
preferably above about 30%wt. Generally, a higher weight percent
of unsaturation compounds is used, say above about 50%wt; most
CA 02162127 2004-O1-23
conveniently the weight percent of the unsaturated hydrocarbons
is lo0gwt (undiluted form and only unsaturated oxygen-containing
hydrocarbon and/or olefins). For example, when the catalyst is
treated with.olefins and oxygen-containing hydrocarbons, the
unsaturation may be provided from olefin and some unsaturated
oxygen-containing hydrocarbon. Of course, unsaturated oxygen-
containing hydrocarbon alone without olefins can also be used.
It is to be understood that the oxygen-containing hydrocarbons
10 may be provided as oxygen-containing hydrocarbon precursors which
are converted to the oxygen-containing hydrocarbon before or upon
reaching the reaction temperature such as, reacting lower
molecular weight acids (e. g. lower than C12 acids) with glycerol
15 to form a higher triglyceride acid ester.
The minimum amount of oxygen-containing hydrocarbon used
should be such that the catalyst obtained that is less
spontaneously combustible. The maximum amount of oxygen-
containing hydrocarbon used is determined primarily by
economics. In a preferred embodiment the amount of substance or
mixtures containing the oxygen-containing hydrocarbon is used
that will just fill the pore volume of the impregnated catalyst
or just slightly less, down to about 50 percent, preferably down
to about 7 0 percent of the pore volume . A general range is from
50 to 95, more preferably from 70 to 90, percent. A preferred
target range is from 80 to 95 percent although greater thari 100%
hydrocarbon can be used. In this manner, the treated catalyst
will be "dry" (flow freely) and is more convenient to handle.
The presulfurized catalyst obtained by the above
presulfurization process may be converted to sulfided catalysts
by contact with hydrogen at temperatures of at least about
200°C, preferably from 200°C to 425°C, or 450°C
for, say, 0.5
hours to up to 3 days.
In preferred operation the presulfurized catalyst is loaded
into a hydrotzeating and/or hydrocracking reactor or tail gas
reactor and hydrogen flow is started to the reactor and the
reactor is heated up to operating (hydrotreating and/or
CA 02162127 2004-O1-23
16
hydrocracking or tail gas treating) conditions to cause
activation of the catalyst the metal oxides and hydrogen react
with substantially all of the sulfur incorporated into the
catalyst pores, thus producing hydrogen sulfide, water and metal
sulfides. In the hydrotreating and/or hydrocracking process, a
hydrocarbon feedstock flow may be started simultaneously with
the hydrogen or later.
The process of the present invention is further applicable
to the sulfurizing of spent catalysts which have been oxy-
regenerated. After a conventional oxy-regeneration process, an
oxy-regenerated catalyst may be presulfurized as would fresh
catalyst in the mannez set forth above.
In applying the oxygen-containing hydrocarbon to the
catalyst, the oxygen-containing hydrocarbon can be added in
batches and mixed or added continuously by spraying the catalyst
with the oxygen-containing hydrocarbon.
The inventive process is particularly suitable for
application to hydrotreating and/or hydrocracking or tail gas
treating catalysts. These catalysts typically comprise Group VIB
and/or Group VIII metals supported on porous supports such as
alumina, silica, silica-alumina or zeolite; they can be prepared
by techniques described in e.g. U.S.-A-4,530,911, 4,520,128 and
4,584,287. Preferred hydrotreating and/or hydrocracking or tail
gas treating catalysts contain a group VIB metal selected from
molybdenum, tungsten and mixtures thereof and a Group VIIZ metal
selected from nickel, cobalt and mixtures thereof, supported on
alumina. Versatile hydrotreating and/or hydrocracking catalysts
which show good activity under various reactor conditions are
alumina-supported nickel-molybdenum and cobalt-molybdenum
catalysts
WO 94/25157 PCT/US94I04394
1, 215 2 .~. ~ ~'
and zeolite-supported nickel-molybdenum and nickel-tungsten
catalysts. Phosphorus is sometimes added as a promoter. A
versatile tail gas treating catalyst which shows good activity
under various reactor conditions is an alumina-supported cobalt
molybdenum catalyst.
Hydrotreating catalysts which are specifically designed for
hydrodenitrification operations, such as alumina-supported
nickel-molybdenum catalysts, presulfurized or presulfided as
described have equal activities, particularly hydrodeni-
trification activities, compared with catalysts without the
oxygen-containing hydrocarbon treatment.Hydrocracking catalysts
such as nickel-molybdenum or nickel-tungsten on a zeolite or
silica-alumina support presulfurized as described provide
increased liquid yield over catalysts without the oxygen-
containing hydrocarbon treatment. Thus, the invention is also
an improved hydrotreating and/or hydrocracking process which
comprises contacting at hydrotreating and/or hydrocracking
conditions a hydrocarbon feedstock and hydrogen with a catalyst
which has been presulfurized as described and which has been
heated to hydrotreating and/or hydrocracking temperature in the
presence of hydrogen and optionally a hydrocarbon feedstock.
The ability to avoid instantaneous combusting provides the
presulfurized catalysts with a significant commercial advantage.
The ex-situ presulfurization method of this invention
allows the hydrotreating, hydrocracking and/or tail gas treating
reactors to be started up more quickly compared with the in-situ
operation by eliminating the presulfiding step. Further, the
presulfurized catalysts of the invention can be handled more
conveniently than the conventional ex-situ presulfurized
catalysts. Thus, the instant invention provides a process for
starting up a hydrotreating and/or hydrocracking reactor, which
comprises loading the catalyst presulfurized as described herein
into the reactor and activating the catalyst by heating the
reactor to operating conditions in the presence of hydrogen and
optionally a hydrocarbon feedstock. Further, it has been found
that catalysts activated by heating the catalyst in the presence
of hydrogen and at least one
SUBSTITUTE SHEET {RULE 26)
WO 94125157 21 6 21 2 7 pCTIUS94/04394
18
feedstock or hydrocarbon having a boiling point at least 35°C,
preferably from 40°C, more preferably from 85°C, to
700°C,
preferably to 500°C at atmospheric pressure, give increased
yields compared to gas activated catalysts. Such hydrocarbons
include, for example, jet fuels, kerosines, diesel fuels,
gasolines, gas oils, residual gas oils and hydrocarbon feed
streams (feedstocks). The catalysts are suitably activated at
a temperature from 25°C to 500°C, preferably to 450°C,
and a
hydrogen pressure of from 50, preferably 350, to 3000 psig. The
hydrocarbon rate will typically have a liquid hourly space
velocity ("LHSV") from 0.1, preferably from 0.2, to about 20,
pref erably 15 , more pref erably 10 , hr'' .
Hydrotreating conditions typically comprise temperatures
from 100°C to 450°C, preferably to 425°C, and pressures
above 40
atmospheres. The total pressure will typically range from 400
to 2500 psig. The hydrogen partial pressure will typically
range from 200 to 2200 psig. The hydrogen feed rate will
typically range from 200 to 10000 standard cubic feet per barrel
("SCF/BBL"). The feedstock rate will typically have a liquid
2o hourly space velocity ("LHSV") from 0.1 to 15.
Hydrocracking conditions typically comprise temperatures
from 100°C, preferably from 150°C, more preferably from
200°C,
to 500°C, preferably to 485°C, more preferably to 450°C,
and
pressures from 40 atmospheres. The total pressure will typically
be from 100 to 3500 psig. The hydrogen partial pressure will
typically range from 100, preferably from 300, more preferably
from 600 psig, to 3500, preferably to 3000 psig. The hydrogen
feed rate will typically range from 1000, more preferably from
2000, to 15,000, more preferably to 10,000, SCF/BBL. The
feedstock rate will typically have a LHSV from 0.05, preferably
from 0.1 to 20, preferably to about 15, more preferably to about
10. First stage hydrocrackers, which carry out considerable
hydrotreating of the feedstock may operate at higher tempera
tures than hydrotreaters and at lower temperatures than second
stage hydrocrackers.
Tail gas treatment reactors typically operate at temp-
eratures ranging from loo°C, preferably from 2o0°C, to about
450°C, preferably 400°C and at atmospheric pressure. Typically
0.5
SUBSTITUTE SHEET (RULE 26~
WO 94/25157 2 1 s 1 2 7 PCT/US94/04394
to 5% vol. of the tail gas fed to the reactor will comprise
hydrogen. Standard gaseous hourly space velocities of the tail
gas through the reactor will range from 500 to 10,000 hr 1.
Claus unit feed or tail gas can be used to start up the
catalysts. Supplemental hydrogen, as required, may be provided
by a gas burner operating at a substoichiometric ratio in order
to produce hydrogen.
In another embodiment of the invention, catalysts in a
refining or a chemical plant reactor such as hydrocracking,
l0 hydrotreating, tail gas treating, hydrogenation, dehydrogenation
isomerization and de-waxing can be treated with the oxygen-
containing hydrocarbon and optionally carrier oil including feed
oil and/or fused-ring aromatic hydrocarbons before unloading
from the reactor, typically when operation is suspended, stopped
or halted by terminating the refining or chemical reaction, for
example by terminating the feed or by lower temperature, the
process provides a method of safely unloading the catalysts with
minimal catalyst oxidation and deterioration. The oxygen-
containing hydrocarbon-containing mixture (mixture can be
undiluted oxygen-containing hydrocarbon) penetrates to the
surface of the catalyst and diffuses into the pores of the
catalysts at the temperature in the reactor after suspension (or
stopping) of its operation, and "coats" the catalyst with a
film.
It is preferred that the temperature within the reactor
column be lower than the smoke point or boiling point (at the
reactor operation pressure) of the oxygen-containing hydrocarbon
when the mixture is added to the catalyst in the reactor. Thus,
after the operation of the reactor is stopped, the feed and/or
catalyst can be cooled from the operating temperature by
allowing the reactor to equilibrate with the ambient
temperature, recycling or by passing feed through a cooling
unit. The feed to the reactor can optionally be shut off. For
many of the oxygen-containing hydrocarbons, the temperature of
the reactor and/or catalyst is preferably less than about
175°C, more preferably less than about 125°C when the
hydrocarbon is contacted with the catalyst at atmospheric
pressure. If the hydrocarbon is contacted with the
SUBSTfTUTE SHEET (RULE 26)
WO 94/25157 PCTIUS94/04394
catalyst ~ t elevated reactor pressures, the reactor and/or
catalyst temperatures can be higher. The contact temperature can
be as low as the unloading temperature or lower. The catalyst
is typically unloaded at a temperature about room temperature
5 to about 70°C.
The oxygen-containing hydrocarbon mixture can be introduced
into a reactor column after suspension of reactor operation. The
mixture can be added to a batch containing the catalysts or to
a recycle stream. Optionally, heavy oil or any similar raw
10 material from the reactor columns can be removed before adding
the hydrocarbon. The catalyst is coated with the hydrocarbon
upon contact and incorporation, thus enhancing the safety of the
unloading operation by protecting the catalyst against oxidation
and rendering the catalyst less spontaneously combustible.
15 A mixture containing the oxygen-containing hydrocarbon
preferably in an amount from 1 to 100 weight percent of the
mixture is contacted with the catalyst in the reactor for a time
effective to coat the catalyst and reduce the self-heating
characteristics of the catalyst. Preferably the mixture should
20 be used in an amount sufficient to coat the surface of the
catalyst.
The oxygen-containing hydrocarbon may be applied in
admixture with a fused-ring aromatic hydrocarbon and/or a
carrier oil. Preferable fused-ring aromatic hydrocarbon include
for example, any fused-ring aromatic hydrocarbon containing at
least 2 rings, preferably 2 to 4 rings, such as naphthalenes
such as alkylnaphthalene; anthracenes such as alkylanthracene;
and pyrenes such as allylpyrene. Such fused-ring aromatic
hydrocarbons may be unsubstituted or substituted for example
with alkyl or aryl moieties. Carrier oil can be any hydrocarbon
stream used in refining operations or a blend thereof having a
flash point of above about 38°C. Preferably carrier oil includes
straight-run heavy gas oil (HGO), vacuum gas oil (VGO), diesel
oil and the like.
The oxygen-containing hydrocarbon and optionally
fused-ring aromatic hydrocarbon and/or carrier oil can be added
through separate lines then mixed or added after being mixed.
If desired, the mixture can be heated with any heating means
such as a heating
SUBSTITUTE SHEET {~U~E 26)
WO 94125157 PCT/US94/04394
furnace, band heater, heating coil or a heat exchanger, to the
desired temperature.
The invention will now be illustrated by the following non-
limiting Examples.
Example I:
This Example demonstrates the case where the catalyst is
first presulfurized and then treated with oxygen-containing
hydrocarbon.
Part A: Sulfur impreanation
A commercial hydrotreating catalyst having the
properties listed below was used.
Table 1: Catalyst Properties
Nickel 3.0 %wt
Molybdenum 13.0 %wt
Phosphorous 3.5 %wt
Support gamma alumina
Surface Area, m2/g 162
Water Pore Vol., cc/g 0.47
Size 1/16 inch trilobes
250 Gram of the above sample was dried at 371°C for one
hour and then cooled to ambient under vacuum. The sample was
then placed in a flask and enough sulfur, in powdered form, was
added at 85°C to produce a sulfur level of about 10% by weight.
The sulfur was allowed to coat the catalyst and then the flask,
which was provided with a slow nitrogen purge and placed in a
heating mantle, was further heated to 120°C for 30 minutes.
During this period the flask was vibrated continually to provide
mixing of sulfur and catalyst. The final sulfur level was about
10% by weight of the total catalyst. The water pore volume of
the sulfur-impregnated catalyst was determined to be about 0.37
cc/g.
Part B: Oxyaen-containing Hydrocarbon Reaction and
Comparative Examules
The sulfur-impregnated catalyst from Part A was impregnated
with the various oxygen-containing hydrocarbons listed in Table
2. Catalyst from Part A was also impregnated with Diesel and
Neodene 14/16/18 alpha-olefins as comparative examples.
SUBSTITUTE SHEET RULE 26)
CA 02162127 2004-O1-23
22
Impregnation was sufficient to fill 80% of the pore volume
calculated by:
(pore volume of catalyst from Part A)(80%)(adjusted weight of
catalyst)(density of oxygen-containing hydrocarbon or compara-
tive campounds)=grams of oxygen-containing hydrocarbon or com- -
parative compounds. The pore volume of the catalyst was~deter-
mined with water (mL/g). "Adjusted weight" is the amount of -
sulfur/catalyst remaining after retains and pore volume
analysis.
The vegetable residue, being solid or semi-solid at room
temperature, was heated up to approximately 80°C before being
applied to the catalyst. All other hydrocarbons were simply
added to the catalyst at room temperature. The catalyst was
shaken With the hydrocarbon until the catalyst appeared dry and
is free flowing. This took approximately 10 minutes per sample.
Once the hydrocarbon was absorbed the catalyst temperature was
allowed to return to room temperature.
150 Grams of the catalyst were loaded into a Miter four
neck flask equipped with a thermocouple through one of the necks
and placed in a heating mantle. Another neck of the flask was
tubed to a another flask equipped with a condenser which was
tubed to a silicone oil-filled container to prevent air back-
diffusion (outlet). Nitrogen flow was established to the flask
through another neck .of the flask (inlet) at 273 cc/m~n. The
remaining neck was stoppered. The flask was attached to a
vibratory table and vibrated for the duration of the 'heat
treatment described below.
The reactor was heated to 260°C over ten to twenty minutes
and held there typically for 30 minutes. After heat treatment
was complete, the reactor contents were cooled to room tempera
ture under nitrogen purge. The samples were analyzed for sulfur
cantent and the exothermic onset temperatures of the samples
were tested.
Part C: Self-Heating Ramp Test
Approximately a 12 gram aliquot of the test sample was
placed in a 3.1 cm diameter, 4.6 cm height sample container,
made of 250 mesh stainless steel net, covered with a 30 mesh
S~.a1I11eSS StS9i T3cv., s.'JTlT.aia ~~ .'~'.O'ic~ ri~7.~r i~3d ~
5~".l~r° ~'Ott01'fl
net with the
WO 94125157 ~ ~ PCT/US94I04394
23
corners bent to form four legs so as to raise the sample
container 0.8 cm off platform.
The sample container was placed in a programmable furnace
at ambient temperature with a stagnant atmosphere. A thermo
s couple was placed in the center of the sample. Another thermo
couple was placed near the sample container to monitor oven
temperature. The oven was ramped at 0.4°C/minute to 450°C. The
temperature data was collected and plotted as described below.
A time-temperature profile was plotted with temperature in
the Y-axis and time in the X-axis for catalyst temperature and
oven temperature.
Exothermic onset temperatures of the temperature profile
test were determined by drawing a 45 degree tangent on the
sample' s temperature trace at the onset of an exotherm. From the
tangent point, a vertical line was drawn to the oven trace then
from that point horizontal to the Y axis for temperature
readings. The results of the self-heating ramp tests are shown
in Table 2 below.
SUBSTITUTE SHEET (RULE 26~
CA 02162127 2004-O1-23
24
Table 2:~Exothermic Onset Temperatures
Ox~rgen-containing hydrocarbon Qnset of Exotherm f°C)
Vegetable Residue °~ 250 -
Distilled Methyl Esters '~ 206
Linoleic Acid °' 244
Fatty alcohol 'a 212
Linseed Oil n 273
Soybean Oil ~ 237 -
Comparative
Diesel ~ 156
Neodene~ 14/16/18 ~ 158
b) A vegetable oil residue from Arista Industries, a mixture
of glycerides, polyglycerides, polyglycerols, diner acids,
hydrocarbon and alcohols comprising 79%wt C1s fatty acids,
and 17%wt C16-fatty acids and having an iodine value of 95-
110.
c) Distilled methyl esters from Arista Industries, Inc. having
100 %wt of composition of CAS Registry No. 68990-52-3.
d) 99% purity linoleic Acid from Aldrich Chemical.
e) Mixture of alcohols from Henkel Corporation 87-95%wt oleyl
alcohol and 2-10%wt cetyl alcohol having 90-95 iodine
value.
f) Raw linseed oil from Anlor Oil Company.
g) RBD soybean oil from Lou Ana Foods.
i) No.2 fuel oil with cetane value of 43 from Exxon Refining
and Marketing Company.
j) An olefin product manufactured by Shell Chemical Co.
93.5%wt. minimum alpha-monooiefin comprising l5~wt. C
alpha-monoolefin, 50%wt. C16 alpha-monoolefin and 35~wt. Ci=
alpha-monoolefin.
Part D: Sulfur Leaching Tests
Toluene was used as a extractive solvent for measuring the
ability of the catalysts to resist sulfur leaching. Generally,
the samples were subjected to a hot toluene extraction then
washed with petroleum ether and dried for analysis. Sulfur
analyses before and following the extraction are used to
calculate percent sulfur retention. A thorough drying of the
sample is necessary to prevent artificially high carbon and
sulfur readings during analysis.
CA 02162127 2004-O1-23
A Soxhlet extractor (200m1) equipped with a boiling flask
(500m1) and Allihn condenser was used. The cotton thimble of the
extractor was filled with approximately 10 grams of catalyst to
be analyzed and loaded into the Soxhlet extractor. The-boiling
5 flask was filled about 3/4 full (about 350m1) with toluene.
Toluene was brought to rapid boiling so a cycle of filling and
emptying of thimble occurs approximately every 7-9 minutes. The
catalyst sample was extracted for a minimum of 4 hours to a
maximum of 18 hours. Extraction was stopped when extract in
l0 siphon tube was water clear. Catalyst was cooled and placed on
a filter in a Buchner funnel and washed with 50 mL of petroleum
ether to displace toluene and then dried in a 100°C oven for 1
hour. Prolonged drying may compromise results by loss of sulfur
from sample. An alternate drying method is to purge the sample
15 with nitrogen for 2 to 3 hours. The extracted catalysts were
analysed for carbon and sulfur content (wt.% and) with a LECO
corporation CS-244 carbon-sulfur analyzer. The percent of sulfur
retained after extraction is shown in Table 3 below. This
percent of retained sulfur is calculated as the amount of sulfur
20 on the catalyst after the extraction of Part D (Fresh Basis
after) divided by the sulfur in the catalyst after the oxygen-
containing hydrocarbon treatment of Part B (Fresh Basis before)
times 100%. Fresh basis was calculated using the following
equation:
25 Fresh Basis Sulfur = Sulfur wt.% / (100-(Carbon wt.% + Sulfur
wt.%)) * 100%.
Table 3: Sulfur Leaching Results
"Reactant" Hvdrocarbon
Amount of Sulfur After Extraction
Oxygen-containinq,hy rocarbon Sulfur Extractability f%)
Vegetable Residue °' 85
Distilled Methyl Esters '~ >95
Linoleic Acid ~ 86
Fatty alcohol '~ 66
Linseed oil n 85
CA 02162127 2004-O1-23
26
Soybean Oil =~ 88
Comparative
Diesel a 77
Neodene~ 14/16/18 ~ 95 -
b)-g), i) and j) as described in Table 2. .
Part E: Sulfur Retention Tests
A commercial hydrotreating catalyst having the properties.
listed below was used to prepare the sulfurized catalysts:
Table 4: Catalyst Properties
Nickel 2.24 %wt
Molybdenum 7.54 %wt
Phosphorus 3.5 %wt
Support gamma alumina
Surface Area, m2/g 309
Water Pore Vol., cc/g 1
Size 1/16 inch trilobes
Sulfur was impregnated according to the method of Part A
using 5.9wt% of sulfur and soybean oil and Neodene 14/16/18 werE
impregnated according to the method of Part B. Carbon and sulfur
content of the catalyst were analyzed using LECO corporation CS-
244 carbon-sulfur analyzer. Fresh Basis Sulfur was calculated
using the equation shown in Part D. Percent Stoichiometric
sulfur was calculated by dividing (the Fresh Hasis Sulf~)~over
(the amount of sulfur added) times 100 percent.
Table 5: Sulfur Retention
Carbon Sulfur Fresh Basis Percent
Sample wt.% wt.% Sulfur wt.% Stoichiometric
Neodene~'~ 26.7 3.0 4.3 73
Soybean~ 33.5 3.5 5.6 95
a) and b) as described in Table 2 as j) and g) respectively.
As can be seen from the Table the percent retention of
sulfur is significantly improved by using a glyceride fatty acid
ester.
Example II:
CA 02162127 2004-O1-23
27
This Example demonstrates the embodiment where the
presulfided or sulfurized catalyst is coated with oxygen--
containing hydrocarbon.
A commercial sulfurized hydrotreating catalyst having the
properties listed below was used.
Table 6: Catalyst Properties
Nickel 3.0 %wt
Molybdenum 13.0 cwt
Phosphorus 3.5 %wt
Sulfur 8 %wt
Support gamma alumina
Size 1/16 inch trilobes
The oxygen-containing hydrocarbon listed in Table 7 was added
to the sulfurized catalyst in an amount listed. The hydrocarbon
was added to the catalyst at ambient temperature and allowed to
absorb into the pores. The treated catalyst may take some time
to absorb the substances so that it is not tacky and flows
freely. The self-heating ramp test was measured in a similar:
manner to Example I, part C.
Table 7: Post-coating
Qxvaen-containing Fivdrocarbon Amount~wt%7 Qr,~set of Exo~herm
(°C1
1:1 wt ratio soybean:linseed 8 280
1:3 wt ratio soybean:linseed 10 260
Example III:
A presulfurized catalyst prepared in a similar manner to
Example I was used in a hydrotreating process. Four types of
catalysts, (1 comparative) were used. These were:
1) COMP Catalyst - the cammercial hydrotreating catalyst
listed in Table 1 which has been sulfided by an industry
3 0 accepted sulf iding method us ing hydrogen and hydrogen sulfide
as described below.
CA 02162127 2004-O1-23
28
2) B Catalyst - a catalyst prepared as described in
Illustrative Embodiment I with 100% stoichiometric sulfur and
using the vegetable residue described in Table 2.
3) D Catalyst - a catalyst prepared as described in
Illustrative Embodiment I with 100% stoichiometric sulfur and
using the methyl esters described in Table 2.
4) E Catalyst - a catalyst prepared as described in
Illustrative Embodiment I with 100% stoichiometric sulfur and
using the vegetable -oil described in Table 2 and Neodene
14/16/18 alpha-olefin described in Table 2 in a weight ratio of
1:1.
The catalysts were loaded into the reactor as follows:
48cc of catalyst (basis compacted bulk density) was divided into
3 aliquots. The first aliquot contained 4 cc of catalyst and was
diluted With 10 to 14 mesh alundum at a ratio of alundum to
catalyst of 10:1. The remaining two aliquots contained 22 c
of catalyst each and were diluted 1:1 with alundum. These
aliquots were loaded into the reactor tube with the dilute one
on top (the inlet end).
Activity Tests
A blend of 50 wt% vacuum gas oil, 25 wt% light cycle
oil and 25 wt% CC heavy gas oil (VGO/ZCO) was used as feedstock
having the following properties:
%wt Sulfur 1.93
ppm Nitrogen 1420
Refractive Index 1.5377 (25°C)
API Gravity 17.8°
1) COMP Cata fist Activation
The Catalyst was dried at 400°C for one hour in air, Gaoled
in a desiccator and loaded into the reactor. It was sulfided
in a flow of 60 N1/hr of 95%vol hydrogen/5%vol hydrogen sulfide
according to the fallocaing schedule: .
21 621 27
29
a, ambient to 218°C in one hour
b. hold at 218°C for one hour
c. heat from 218°C to 329°C in one hour
d. heat from 329°C to 343°C in one hour
e. hold at 343°C for one hour
f. cool reactor and hold at 246°C
2) Diesel Activation
This method was used to activate catalysts using a diesel
refined for cars and trucks and was as follows:
a. Unit was pressurized to 700 prig and hydrogen
circulation was established at 1000 SCF/HHL ( Nl/hr).
b. Diesel feed was started to the catalyst bed at 1.5
LHSV and ambient temperature.
c. The reactor temperature was raised to 121°C in one
hour, then increased to 343°C at rate of 27.8°C/hour.
Temperatures were held at 343°C for 30 minutes.
d. The reactor was then cooled over 2 hours to 246°C.
3) Activity Testing
For activity testing the unit was pressured up to 700 psi~
and heated to 246°C with a hydrogen gas rate of 220 SCF/bbl
(13.2 N1/hr). The VGO/LCO feed was started to the unit at 1.5
LHSV (66 gm/hr). After the feed had wetted the entire bed (and
product was noted in the separator), the temperature was raised
to 329°C at 22.2°C/hr. _.
After the reactor was at 329°C, a 12 hour break-in period
was begun. The product from this period was not analyzed'. The
run was continued with additional weight periods of 12 hours and
the products of third weight period (37-48 hours) were analyzed
for nitrogen and sulfur. From these values rate constants were
calculated for the hydrodenitrification ("HDN") reaction and the
hydrodesulfurization ("HDS") reaction. These provide an
indication of how active the catalyst is, the higher the rate
constant, the faster the reaction process, and the higher the
conversion of sulfur and nitrogen at a given space velocity
(feed rate). For HDN
r
CA 02162127 2004-O1-23
t spa ce ve1 oci ty) * In ~ conc . of N in feed ~ _
canc. of N in product
For FiDS the reaction is not first order and many values are
used, but 1.7 is the value most used and is used herein to _
5 calculate as follows:
R = ~ apace veloci ty~ 1 _ 1
1.7-1 ~ (conc. of S in product) °~' (couc. of S in feed) °~'
the reactian order is 1.0 and the k value is calculated by the
equation
The relative rate constants are provided in Table 8, normalized
against the values for the third weight period for the COMP
Catalyst.
Table 8: Activity Tests
10 Weight Period
Cafi~lyst Activation ~S Rel.~C Value I3DN Rel. K Value
COMP 1) Standard 1.00 1.00
B 2) Diesel 1.04 0.94
D 2) Diesel 0.94 1.02
E ,, 2) Diesel 1.00 1.01
. As can be seen the catalysts of this invention show a
comparable hydrodenitrification activity (without significant
decrease in activity) to a traditional hydrotreating catalyst.
Further, catalysts containing unsaturated hydrocarbons show
advantage over catalyst with only saturated hydrocarbons with
regard to the hydrodenitrification activity.
Example Iy:
Z-753 Ni-W/Ultrastable Y zeolite based hydrocracking
catalyst, (from Zeolyst International Inc.), was presulfurized
WO 94125157 PCTIUS94/04394
31
according to the procedure outlined in Example I.
Sulfur was incorporated according to the method of Part
A using 5.5 wt% of sulfur. Soybean oil and Neodene were
impregnated on the catalyst according to the method of Part
B. Carbon and sulfur content of the catalyst were analyzed
using LECO corporation CS-244 carbon-sulfur analyzer. Fresh
Basis Sulfur was calculated using the equation shown in Part
D. Percent Stoichiometric sulfur was calculated by dividing
the Fresh Basis Sulfur percent by the percent sulfur
calculated for complete conversion of the oxidic nickel and
tungsten to the corresponding Ni3Sz and WSZ phases.
Table 10: Sulfur Retention
Carbon Sulfur Fresh Basis Percent
S a wt.% wt.% Sulfur wt.% Stoichiometric
Neodene' 11.1 1.4 1.6 43
Soybeanb 20.5 2.4 3.1 84
a) as described in Table 2 as j)
b) as described in Table 2 as g)
As can be seen from Table 10, the percent retention
of sulfur is significantly improved by using a glyceride
fatty acid ester such as soybean oil.
Performance Tests
A blend of 75 vol% hydrotreated cracked heavy gas
oil, and 25 vol% hydrocracker bottoms stream was used as
feedstock for performance testing of the zeolitic
hydrocracking catalysts obtained from Example IV and the
fresh Z-753 (Reference Catalyst). Some of the feedstock
properties are listed in Table 11. DMDS and n-amylamine were
added to the feedstock to generate the requisite levels of HzS
and NH3, respectively.
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Table 11: Performance Testing Feedstock Properties
ppm Sulfur 14
ppm Nitrogen 25
wt% Carbon 87.334
wt% Hydrogen 12.69
API Gravity 26.1°
338+ °C (wt%) 71.4
DMDS (wt%) 0.133
n-amylamine (wt%) 0.079
Simulated Distillation of Feedstock
TEMP °C
IBP 181
5% 248
25% 330
50% 382
75% 434
90% 481
98% 537
FBP 572
Performance Testing Conditions
The conditions employed for the performance testing
of the zeolitic catalysts above are given in Table 12.
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Table 12: Performance Testing Conditions
Hydrogen Pressure (psig) 1800
Hydrogen Circulation (scf H2/bbl feed) 8935
LHSV (hrl) 1.5
Cut Point for converison calculation (°C) 338°
Conversion Target (Single Pass, wt%) 80.0
Catalyst Activation Procedures
1) Zeolite Reference Catalyst: Gas Phase Activation
The fresh Z-753 catalyst was dried at 482°C for one hour
in air, cooled in a desiccator and loaded into the reactor.
It was sulfided in a flow of 95% vol hydrogen/5% vol hydrogen
sulfide at a GHSV of 1500 hr~, according to the following gas
phase schedule:
a. ambient to 149°C, hold 1 hour
a. 149°C to 371°C in six hours
b. hold at 371°C for two hours
c. cool reactor to 149°C and hold
d. switch to pure hydrogen flow
lb) Zeolite Reference Catalyst: Liguid Phase Activation
To activate the zeolite catalyst, after loading it
dried, the reactor was brought to 1800 psig pure hydrogen, at
a circulation rate of 8935 scf hydrogen/bbl feed. The acti-
vation feedstock employed consisted of the performance
testing feedstock containing sufficient dimethyldisulfide
(DMDS) to produce 2.5 vol% H2S, and n-amylamine to produce 150
ppm NH3 in the gas phase, respectively. The procedure for the
activation was as follows:
a. reactor brought to operating pressure and hydrogen
rate
b. activation feedstock introduced at 149°C
c. 149°C to 232°C in 3 hours
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.w
d. 232°C to 302°C in 18 hours
e. 302 °C to 315 °C in 8 hours
f. hold 315 °C for 8 hours
g. switch to activity testing feedstock and adjust
temperature to maintain 80 wt% conversion of feed.
During steps c-f, H2S and i-butane were continuously
monitored in the exit gas stream of the reactor. Temperature
was ramped as long as HZS remained above 2000 ppmv, and
isobutane concentration remained below 0.4 vol%. Otherwise,
the ramp was discontinued until these levels were realized.
2) ~eolitic Catalyst:
Gas Phase Activation with 5 0% vol H2S.
The zeolitic hydrocracking catalyst from Example IV
was dried at 482°C for one hour in air, cooled in a
desiccator and loaded into the reactor. It was activated in
the same manner as the catalyst in case 1) of this Example.
2a) _Zeolitic Catalyst:
Gas Phase Activation with 0 5% vol HiS.
After reactor loading 25 cc of the zeolitic
hydrocracking catalyst from Example IV and pressure testing,
the following procedure was used for a gas phase activation
that simulates 0.5% HZS in the recycle gas:
a. pressurize reactor to 450 psig with pure HZ and establish a
GHSV of 320 hrl.
b. ramp temperature at 14°C/hr to 120°C; begin sampling the
reactor off-gas for HZS each 0.5 hr.
c. switch to 0.5% H2S/95.5% Hz mixture
d. ramp temperature to 205°C at 14°/hr.
e. at 205°C, increase pressure to 1500 psig and establish a
GHSV of 850 hr'1.
f. ramp temperature to 370°C at 14°C/hr, interrupt ramp if
HzS in reactor off-gas drops below 2000 ppmv.
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g. hold at 370° for 4 hours
h. cool to 149°C
i. switch to pure HZ and set pressure and flow rates for
performance testing
5 2b) Zeolitic Catalyst: Liquid Fged Activation
The same method as for reference catalyst liquid
activation was used to activate zeolitic catalyst from
Example IV. The same activity testing feed was used with
sufficient dimethyldisulfide (DMDS) and n-amylamine added to
10 produce 2000 ppm HZS and 150 ppm NH3 in the gas phase,
respectively. DMDS was added to the feed in order to simulate
a minimum level of HZS that could be tolerated during
activation in the gas recycle loop of commercial units.
All gas phase activated catalysts (1), (2), (2a):
15 After activation with the hydrogen sulfide/hydrogen mixture,
the reactor was cooled to 149°C and the following startup
procedure was implemented:
a. introduce activity testing feed at 149°C
b. 149°C to 260°C in 5 hours
20 c. 22°C/day for 4 days
d. 5.5°C/day for 5 days
e. adjust reactor temperature to maintain 80 wt%
conversion of 338+ °C in feed.
Conversion (wt%) is defined as follows:
25 100 x ~Wt% 338+ °C in feed - Wt% 338+ °C in uroductl
(Wt% 338+ °C in Feed)
In this conversion definition, gaseous products are included.
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Performance Testing Results
Liquid and gas product streams were both analyzed and
mass balanced yields based on feed oil and hydrogen were
calculated. Representative weight period results from
testing of the three zeolite catalysts are found in Table 13.
Values for product cuts are reported as mass balanced wt%
based on feed.
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Table 13. Representative performance measures for zeolitic
hydrocracking catalysts.' Values reported are calculated for
80% conversion.
PRODUCT CUTS (°C)
Cata ystb Temp ,~1~ C,-5, 82° 82-190° 190-288° 288-
338° 338°+
1 378 15.0 23.0 37.8 9.1 2.7 14.5
ib 381 17.1 23.5 35.4 8.0 3.3 14.5
2 378 12.1 18.5 40.6 12.3 3.6 14.5
2a 381 14.4 19.3 39.7 11.5 3.7 14.4
2b 377 11.8 19.1 42.0 10.9 3.2 14.5
Catalyst° Temp ,~,~,, 82-190190 190-288 288-338 338+
1 384 17.7 25.4 34.9 7.3 2.3 14.6
2a 387 17.3 22.9 35.1 8.8 3.3 14.5
2b 381 13.2 19.9 40.9 10.4 2.9 14.5
(a) Absence of a letter following the catalyst reference
number denotes gas phase activation with 5% H2S/95% HZ, "a"
following the catalyst number denotes gas phase activation
with 0.5% HZS/99.5% H2, and "b" denotes liquid phase
activation. (b) Values reported are for 700 hours on feed.
(c) Values reported are for 1400 hours on feed.
As can be seen from Table 13, the zeolitic catalysts of
this invention (2,2a,2b) show a significant improvement in
liquid yield relative to the reference catalysts (1 and lb).
This improvement occurs regardless of whether the reference
catalyst was activated in liquid phase or gas phase, but the
more appropriate
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comparison of the two liquid phase activations reveals the
greatest advantage for the invention catalyst. In this case,
the catalyst also exhibits an advantage in activity, with a 3 °C
lower temperature requirement at 80 wt% conversion.
Table 14. Yield stability data on selected cuts for reference
and invention catalysts.
C1-C4 Yields 82-190°C Yields
HOURS =_> 500 1000 1600 500 1000 1600
Catalyst
1 13.8 16.6 18.3 38.6 36.4 34.5
lb 15.4 19.5 - 37.3 32.8 -
2 11.1 14.2 - 41.4 39.0 -
2a 11.6 14.8 16.8 40.6 37.8 35.5
2b 10.1 12.7 13.2 43.0 41.0 40.7
Table 14 illustrates the additional benefit of yield
stability associated with the process of liquid phase activation
of the catalysts prepared according to Example IV. Both the gas
phase activated reference catalyst (1) and the liquid phase
activated invention catalyst (2b) have an initial C1-C4 yield
decline rate of 5.6 wt%/1000 hrs. However, in the case of (2b),
the yield decline rate between 1000 and 1600 hours on feed has
dropped to 0.8 wt%/1000 hrs, while that of (1) is 2.8 wt%/1000
hrs. The case is even more dramatic when examining the naphtha
range (82-190°C) liquid yields. The 1000-1600 hours yield
decline rate for (1) is 3.2 wt%/1000 hrs, while that of (2b) is
only 0.5 wt%/1000 hrs.
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This yield stability can translate into significant improvement
in output of valuable products for the refiner, at the same time
decreasing the production of the less valuable C1-C4 stream.
Example V
In this Example a spontaneously combustible or self-heating
catalyst is unloaded from a reactor after treatment with oxygen-
containing hydrocarbon.
A highly self-heating, spent, hydrotreating catalyst listed
below (obtained from a hydrotreating reactor) was treated with
1.5 Wt. % soybean oil in a carrier oil (feed stream) and a
second sample of same material was treated with 100% soybean
oil. The mixtures were heated to 140°C under nitrogen for one
hour and then cooled and drained. The material was tested for
self-heating properties according to Appendix E of 49 CFR 173
(Test for Class 4, Division 4.2 Substances in Code of Federal
Regulations), which requires a 2.5 cm cube size sample and a 10
cm cube size sample.
The samples were further analyzed for exothermic onset by
a Differential Scanning Calorimetry, Mettler's TA 4000 using a
DSC27HP DSC measuring cell. For the purposes of this test the
onset and half the distance along the trace to the first peak
were entered to calculate the onset temperature and slop of the
curve. The sample was heated from 30°C to 500°C at 10°C
per
minute. A 500 cc/min of air purge the DSC measuring during the
test.
Catalyst Properties:
Cobalt/Molybdenum on activated alumina
Size 1/20 inch
Shape Quadralobe
Form Spent
Carbon 12.9 Wt. %
Sulfur 7.9 Wt. %
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Both samples treated with soybean oil (at 1.5 and 100%)
passed the Large Basket Test as described in Appendix E of 49
CFR 173. The untreated sample failed the Large Basket Test.
Exothermic Onset temperatures for the samples determined
5 by DSC are as follows:
Table 15
Sample Onset Temperature Integration*
(C) (J~g)
Untreated Sample 140 2857.6
1.5 Wt.% Soybean Oil 238 392.2
10 100 Wt.% Soybean Oil 232 261.0
* samples integrates rrom onset zo 5uu°c:
Samples treated with soybean oil have reduced self-heating.
The sample treated with 100% soybean oil have a smaller overall
exotherm than the 1.5 Wt.% treated sample as shown by the
15 integration values for each sample.
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