Note: Descriptions are shown in the official language in which they were submitted.
lO~Of~
1 FIELD OF THE INVENTION
2 The instant invention relates to a process for
3 activating catalysts which are activated by reducing at
4 elevated temperatures. The catalysts are preferably massive
nickel catalysts, comprising nickel and silica most pref-
6 erably also copper and being characterized as having a
7 nickel surface area of from 50 to lOO m2/g and a total
8 surface area of from 150 to 300 m2/g, said catalysts being
9 prepared by a process comprising the step of contacting a
porous support with a solution containing nickel9 copper
11 and silicate ions, at conditions whereby said ions are co-
12 precipitated onto said support to yield a composite com-
13 prising nickel, copper and silica precursors on said porous
4 support.
BACKGROUND OF THE PRIOR ART
16 Massive nickel hydrogenation catalysts having high ~-
17 nickel surface areas, for example, more than 70 m2/g, are
18 known in the art. U.S. Patent 3,868,332 teaches such a
19 catalyst characterized as having a low sodium content3 i.e. 9
less than 0.2 wt. % based on total weight of catalyst. In
21 U.S. Patent 3,859,370 the use of this catalyst in hydrogen~
22 ation processes is claimed.
23 SUMMARY OF THE INVENTION
24 This invention relates to a process for the
activation of catalysts which are activated at elevated
26 temperatures in the presence of a reducing gas, preferably
D nickel-silica catalysts which contain (preferably) very
28 small amounts of alkaline impurities. In a preferred
29 embodiment this catalyst additionally comprises copper.
The instant invention relates to an improved
- 2 -
10~0~
1 method for activating cntalysts which are commonly scti-
2 vated by red~ction at elevated temperatures, for example,
3 at least 150Co The catalyst prior to this activation step
4 may be prepared by any method known in the art. For
example, in preparing a supported catalyst which comprises
6 a metal supported on an inert, porous support, a catalyst
7 metal precursor will be impregnated or precipitated onto
8 the support or, alternatively, the supported catalyst may
9 be formed by coprecipitation9 from solution9 of the precur-
lo sors of both the metal and the support. The solution may
1 comprise any solvent in which the catalyst metal precursors
12 are soluble, i.e., the solvent may be aqueous or nonaqueous.
13 The excess solvent will be removed by methods known in the
14 art, including heating and/or use of ~ v~cuum. After
solvent removal, if desirable, a calcinatiGn in air or an
16 inert gas may be carried out.
17 The improved process of the instant invention is
18 especially suitable for preparing hydrogenation catalysts
19 which are activated by reduction at high temperature. Most
especially, the process of the instant invention is useful
21 for activating the massi~enickel hydrogenation catalysts
22 described in the hereinabove referred to patents. In its
23 most preferred embodiment, the process of the instant
24 invention is utilized to activate the catalysts which
comprise nickel, copper and silica coprecipitated onto a
26 porous support which may be particulate.
27 In one preferred embodiment, the importance of
28 the instant invention resides in the fact that many
29 commercial hydrogenation units are limited to a maximum
~ temperature at the inlet of about 200C to 250C. It is
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~ noted that there are commercial hydrogenat~on units wherein
2 a furnace is used to preheat the feed at the inlet, however
3 these units must be designed for tempe~atures of from 350C
4 to 400C, since the nickel silica catalyst must be reduced
at a temperature of at least about 350C for complete
6 activation. Thus the catalyst is generally reduced and
7 stabilized by the manufacturer. T~is requirement, however,
8 increases the cost of the catalyst and makes in situ
9 activation more attractive. Because of the above limitation
10 on inlet temperature, prior to the discovery of the process -
11 of the instant invention, in situ techniques were not
12 commonly available to the commercial users of nickelosilica
13 hydrogenation catalysts.
14 In a preferred embodiment of the process of the
instant invention the massive nickel catalyst 9 which is a
16 high surface ares nickel catalyst preferably eonta;ning
17 copper, is charged into the hydrogenation reactor in a
18 manner designed to minimize absorption of water from the
19 atmosphere. The reactor may be purged with dry air or a
~ dry inert gas to remove traces of water from bo~h the
21 reactor and the catalyst. The reactor is closed and then
22 purged with an inert gas to remove oxygen~ When the oxygen
23 level is sufficiently low, i.e. less than 1%, the purge
24 gas is terminated and a reducing gaS9 preferAbly a hydrogen~
rich gas is passed over the catalyst at a flow rate of from
26 l,000 V/Hr/V to 509000 V/Hr/V, preferably 5~000 V/Hr/V. The
27 reducing gas iS bled into the reactor with steadily in- -
28 creasing flow up until the point where full flow has been
29 obtained. Then the temperature at the inlet is increased
in increments of 10C to 30C at thirty minute intervals
- 4 -
10~
1 until a temperature of from 210 to less than 235C is
2 achieved within the catalyst bed. This temperature is
3 maintained for a time sufficient to provide a partially
4 activated catalyst composite9 i.e. 9 with 10~75~/o of the
S activity of a fully activated catalyst. The catalyst at
6 this point is an active cstalyst, although9 due to the
7 fact that much of the nickel exists in the nonmetallic
8 (noncatalytically active) state, the catalyst is charac~
9 terized as being partially activatedO However9 as will
0 be further described below9 it is critical ~hat suffi~ient
11 nickel exist in the metallic 9 iOe. catalyticaliy active
12 state to yield a composite having some catalytic activity.
13 The temperature at the inlet is then l~wered to from ~bout
14 100C to 125C and the flow of a reactive feed through the
catalyst bed is commenced. The reactive feed when a
16 hydrogenation catalyst is being activated by the process
17 of the instant invention is conveniently an unsaturAted
18 hydrocarbon, i.e.~ either an aromati~ or olefinic hydro~
19 carbon; or oacygenated derivatives thereof9 eOgO alcohols9
~ ethers, etc. Examples of reactive feed which sre useful
21 in the process of the instant invention includeo C2 to ~ -
22 C20 olefins, C6 to C20 aromatic hydrocarbons9 e.g. benzene9
23 toluene, xylene~ hexene 9 butadiene~ styrene 3 etc. The
24 reactive feed may be 100% olefinic or aromatic or comprise
mixtures of olefins and aromatics. Nonreactive comp~nents
26 such as paraffins may also make up a portion of the
27 reactive feedstream. Hydrogen is provided with the
28 reactive feed since it is necessary as a reactant and to
29 reduce the nickel to the metal. It is critical to tSe
~ process of the instant invention thst the reaction used to
10~0~
1 activate the partially activated catalyst composite must be
2 exothermic since the purpose in contacting the catalyst
3 with a reactive feed, at this point, is to utilize the
4 heat of reaction to obtain a higher temperature at the
surface of the catalyst than is available at the inlet or
6 in the catalyst bed. Thus, the skilled artisan would
7 adjust the reactive feed accordingly to obtain sufficient
8 heat of reaction to convert the partially activated catalyst
9 into a high activity catalyst, i.e., a catalyst with more
lo than 75% of the activity of a fully activated catalyst.
11 The temperature during the contacting of the
12 partially activated massive nickel hydrogenation catalyst
13 with the reactive feed is raised 9 in increments of 10C to
14 30C per thirty minute interval9 until the maximum
temperature in the catalyst bed exceeds 235C9 preferably
16 the temperature is raised to between 235C and 275C.
17 The ratio of the reactive feed to hydrogen and
18 flow rates of both are adjusted to achieve a sufficient
19 exotherm to raise the temperature of the catalyst in the
bed to a level of about 2500275C or more. The catalyst
21 will be maintained at this temperature by means of the
22 reaction occurring for a time sufficient to achieve9
23 preferably full, i.e., 100%, activation of the catalyst,
24 approximately 2 to 20 hours.
The massive nickel catalyst activated by the
26 process of the instant invention are useful in hydrogena~
27 tion and may be used to hydrogenate aromatics, aldehydes,
28 alcohols, olefins, including both straight and branched
2g chain, and the various hydrocarbon double bonds found in
edible fats and oils~
lO~V~5
1 EXAMPLES
2 The following examples best illustrate the process
3 of the instant invention. The catalyst used in all the
4 tests was prepared according to the following method:
8.75 gm. of Cu(NO3)2 3H20 and 112 gm. of Ni(NO3)2-6H20 were
6 dissolved in 500 ml of distilled water, then 38 gm. of
7 Na2SiO3 9H2O was dissolved in another 500 ml of water and
8 5 gm. of acid washed kieselguhr was slurried in this
9 second solution. The second solution with the kieselguhr
lo slurried therein was stirred vigorously while the first
11 solution containing the copper and nickel salts was added
12 at a uniform rate over a 20 minute period. This mixture
13 was then heated to the boiling point and 80 gm. of NH4HC03
14 was added at a uniform rate over a 20 minute period. The
mixture was kept at the boiling point for 3 hours while
16 stirring continued. It was then filtered and washed 5
17 times with boiling water, each wash consisting of 500 ml
18 of water. The filtercake was then dried at 120C and
19 calcined in air for 4 hours at 400C. The catalyst contained
by weight 45.0% nickel, 5.0% copper, and 50% silica (the
21 impurities present in the acid washed kieselguhr being
22 included in the weight of silica given).
23 In Example A the catalyst was sctivated in H2,
24 at a catalyst bed temperature of 245C, with a nonreactive
2s feed flow. In Example B, the catalyst was activated in
26 H2, at a catalyst bed temperature of 245C, with a reactive
27 feed which contained 22~3% aromatics. In Example C, the
28 catalyst was activated in H2, at a catalyst bed temperature
29 of 245C, with a reactive feed which contained 21~77o
~ aromatics. In Example D, the catalyst was activated first
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1 with H2 at a catalyst bed temperature of 232C, then with a
2reactive feed which contained 21.7% aromatics at 245C.
3TABLE I
4 ExamPle A ExamPle B
Conversion of
6 aromatics at
7 100 hours on oil 60% 80%
8 Run Conditions:
9Space Velocity - 10 Volume feed/Hr/Volume
10Catalyst
11 Pressure - 600 psig
12 Temperature - 160C
13 H2 - 1000 Standard Cubic Feet/
14 Barrel
Feed - Mineral spirits*
16 22.3% aromatics
17 TABLE II
18 ExamPle C ExamPle D
19 Conversion of
aromatics at
21 75 hours on oil 24% 34%
22 Run Conditions:
23 Space Velocity - 30 Volume feed/Hr/Volume
24 eatalyst
Pressure - 600 psig
26 Temperature - 160C
2i H2 - 1000 Standard Cubic Feed/
28 Barrel
29 Feed - Mineral spirits*
21.7Z aromatics
31 *The mineral spirits used was VARSOLTM #3, from
32 Exxon Chem. Co. U.S.A., which i8 a naphtha
33 fraction with a boiling range of 310F to 341F,
34 aromatics content of from about 21 to 23% on a
wt. basis and 1.5 ppm sulfur or less.
lO~V~S
1 In Table I, Example B shows significantly higher
2 conversion than Example A. The data in Table II show the
3 added improvement obtained by the activation procedure
4 described in this application. Example D shows substan-
tially more conversion than Example C which did not include
6 a treatment with H2 prior to the high temperature activation
7 with the reactive feed. Thus, the data in Tables I and II
8 demonstrate the criticality of the two step activation
9 process of the instant invention.
It should be noted, for purposes of definition,
11 Example D represents a fully active catalyst composite,
12 while Examples A, B and C, represent partially active
13 catalyst composites, i.e., they have an activity (as
14 measured by the reaction described in Example D and defining
the catalyst activity of said catalyst composite as 100%)
16 of from 10 to 75%.
