Note: Descriptions are shown in the official language in which they were submitted.
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The Calladi~n application 233,512 filed Au~gust 15, 1975 relates to a
process for extracting vanadiu~. from a catalyst which has been
deactivated by use in the treatment o~ a hydrocarbon oil containing
vanadium with hydrogen at elevated temperature and pressure,
during which treatment the vanadium content of the catalyst has
increased by at least 1G pbw. According to the said application
233,512 the extraction of the vanadium, whereby the
vanadium content o~ the catalyst is decreased by at least 40%
of the amount by which it has risen during the deactivation, is
carried out by extracting the deactivated catalyst with an
aqueous solution of a mineral acid, after which vanadium is
separated from the vanadium-containing solution thus obtained.
If the process is applied to a catalyst that has been deactiv-
ated in the hydrotreatment of a hydrocarbon oil containing
nickel in addition to vanadium, during which treatment the
nickel content of the catalyst has increa~sed as well, nickel is
also removed ~rom the catalyst in the process. Besides the
extraction of vanadium and optionally nickel from deactivated
catalysts, the process is also applicable to the regeneration
of deactivated catalysts so that they can be used again for
catalytic purposes.
According to the said application 233,512
the acid extraction is preferably carried out in the presence of a
reducing agent. Also, according to the said application 233,512
it is preferred to treat the deactivated catalyst
first with steam to remove sulphur and then with an oxygen con-
taining gas to remove carbon~ prior to subjecl ~g it to acid
extraction. It ~hou~d be r~marked that, when the aim is not
only to exkract vanadium and optionally nickel from the cata-
lyst, but also to regenerate the catalyst, the treatment of the
deactivated catalyst with an oxygen-containing gas in the way
indicated in the examples o~ the said application 233J512
whereby a small portion of the deactivated catalyst
is treated with air for three hours at 550C, is not suitable
for larger quantities of deactivated catalyst because of the
large amount of heat that would be liberated.
When larger quantities of deactivated catalyst had to be
treated with a view to extracting vanadium and optionally
nickel from the catalyst as well as regenerating the catalyst,
the following three-stage procedure was until recently con-
sidered to be the most attractive embodiment of the process
according to the said application 233~512
The deactivated catalyst is first treated for 1-5 hours at
250--450C and atmospheric pressure with a mixture of steam and
nitrogen, then for 1-5 days at 350-600C and atmospheric pres-
sure with a mixture of air and nitrogen and finally it is
subjected to acid extraction in the presence of a reducing
agent for 0.5-3 hours at 50-150C. The treatment times required
in the various stages are dependent upon, inter alia, the
quantities of sulphur, carbon and metabs which are present on
the deactivated catalyst and the conditions chosen, vi~. treat-
ment temperatures, gas flow rates and compositions of treating gases
and extraction liquid. Up to now the long treatment time required
in the second stage of the three-stage procedure has been
considered a serious drawback for using the process according
to the said application 233~512 on a commercial
scale.
Continued investigation of the process as described in the
said application 233,512 has now led to the finding
that a comparable res~llt can be obtained as regards vanadium
and nickel removal and activity of the regenerated catalyst to
that achieved by conducting the process according to the
three-stage procedure described hereinbefore, but in a much
shorter time, if the acid extraction in the presence of a
reducing agent is preceded by treatment of the deactivated
catalyst at a temperature above 250C with a mixture of steam
and air of which the steam~air ratio is more than 1.0 at a
~team partial pressure above 1 bar. In addition to the fact
that with the process now found a much shorter treatment time
will suffice for achieving a comparable result as regards
vanadium and nickel removal and activity of the regenerated
catalyst, this proceqs has two additional advantages over the
abov~-mentioned three-stage procedure in that both the number
of treatment stages and the number of gases necessary for
treating the deactivated catalyst prior to the acid extraction
have decreased by one.
The present patent application therefore relates to an
improved process for extracting vanadium from a deactivated
catalyst according to the said application 233,512
in which process vanadium is extracted from a catalyst
which has been deactivated by use in the treatment of a vana-
5 _
dium-containing hydrocarbon oil with hydrogen at elevated
temperature and pressure, during which treatment the vanadium
content of the catalyst has increased by at least 10 pbw, and
in which process the said vanadiu~ extraction, whereby the
vanadium content Or the catalyst is reduced by at least 40% of
the amourt by which it has risen during the deactivation (vana-
dium content of the catalyst expressed in pbw vanadium/100 pbw
catalyst carrier~, i9 carried out by extracting the deactivated
catalyst with an aqueous solution of a mineral acid (called
hereinafter "acid extraction"), after which the vanadium is
separated from the vanadium-containing solution thus obtained.
The improvement consists in that the acid extraction which
is carried out in the presence of a reducing agent, is preceded
by a treatment of the deactivated catalyst at a temperature
above 250C with a mixture of steam and air in which the
steam/air ratio is more than 1.0 at a steam partial pressure
above 1 bar.
In the process according to the present invention the
treatment with the mixture of steam and air should be conducted
at a temperature above 250C, but preferably below 600C and in
particular at a temperature between 325 and 425C. In the
treatment of the deactivated catalyst with the mixture of steam
and air the steam partial pressure should be more than 1 bar,
but preferably below 5 bar and in particular between 2 and 4
bar. The steam/air ratio of the steam/air mixture used should
be more than 1.0, but preferably lower than 10 and in partic-
ular between 4 and 8.
The acid extraction in the presence of a reducing agent to
8;~
which the deactivated catalyst should be subjected in the
process according to the inventionS i9 preferably carried out
at elevated temperature, in particular at a temperature above
50C. The said extraction is preferably conducted with an
aqueous solution of sulphuric acid which has been saturated
with sulphur dioxide.
When the process according to the invention is applied to
deactivated catalysts which contain nickel in addition to
vanadium, it may be advisable to extract the deactivated cata-
lyst with water after the treatment with the steamJair mixture.By this extraction with water, which is preferably carried out
at elevated temperature and in particular at a temperature
above 50C, an aqueous nickel-containing solution is obtained
~rom which the nickel can be extracted.
The process according to the presellt invention is partic-
ularly important in those cases in which the aim is not only to
extract vanadium and optionally nickel from the deactivated
catalyst, but also to regenerate the catalyst (which may, in
the fresh condition, contain one or more metals with hydrogen-
ation activity) so that it can be used again for catalytic
purposes. The present patent application relates therefore not
only to a process for extracting vanadium and optionally nickel
from a deactivated catalyst, but also to a process in which
this extraction is conducted in such a way that a regenerated
catalyst is obtained which can be used again Por catalytic
purposes, either as such, or after a complementary quantity of
metals with hydrogenation activity has been added to it. The
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process according to the invention is especially important for
extracting vanadium and optionally nickel from a catalyst
substantially consisting of silica, in combination with re-
generation of the catalyst, which catalyst has been u~ed in a
proces~ for the hydrodemetallization of a hydrocarbon oil.
The invention will now be explained with reference to the
following examples.
EXAMPLE_I
A catalyst comprising 0.5 pbw nickel and 2.0 pbw vanadium
per 100 pbw silica carrier was prepared by impregnat;ng a
silica carrier with an aqueous solu~ion of nickel nitrate and
vanadyl oxalate, after which the composition was dried and
calcined. The catalyst (catalyst A) was used in the sulphidic
form for the hydrodemetallization of a hydrocarbon oil (oil A)
with a total vanadium and nickel content of 62 ppmw, a C5-as-
phaltenes content of 6.4 ~w and a sulphur content of 3.9 %w,
which oil had been obtained as the residue in the atmospheric
distillation of a crude oil from the Middle East. The hydrode-
metallization was carried out by passing the oil together with
20 hydrogen in a downward direction through a cylindrical, ver- !
tically disposed fixed catalyst bed at a temperature of 420C,
a total pressure of 150 bar, a spaoe velocity of 5 kg.l 1.h 1
and a gas flow rate (measured at the reactor outlet) of 250 Nl
H2.kg 1. The activity of the catalyst, expressed as "% vanadium
removed" (= average vanadium removal over the period of cata-
lyst age from 1 tonne oil/kg catalyst to 4 tonnes oil/kg cata-
lyst), was 51. After the catalyst had been deactivated in this
S8~
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process, it was extracte(! with toluene to remove remnants of
residual oil and after evaporation of the toluene from the
catalyst the latter was analysed. The deactivated catalyst
(catalyst B) contained 9.7 pbw carbon, 20.6 pbw sulphur, 4.1
pbw nickel and 24.3 pbw vanadium per 100 pbw silica.
EXAMPLE II
5 kg of Catalyst B was treated with a 4:1 steam/nitrogen mixture
for three hours at 350C, atmospheric pressure and a gas flow rate of
2 Nl gas mixture~(g catalyst) 1.h-1. The catalyst was then treated
with a 1:19 air/nitrogen mixture for 50 hours at 400C, atmos-
pheric pressure and a gas flow rate of 1 Nl gas mixture (g
catalyst) 1.h 1. Finally, the catalyst was extracted for two
hours at 90C with stirring with 40 l 2 N sulphuric acid which
had been saturated with sulphur dioxide~ After the extracted
catalyst had been washed with water, it was dried at 120C and
calcined for three hours at 550C. On analysis of the catalyst
thu~ obtained (catalyst C), 96% of the vanadium and 95% of the
nickel were found to have been removed from the catalyst by
this treatment.
EXAMPLE III
5 kg of Catalyst B was treated with a 7:1 steam~air mix-
ture for 25 hours at 400C, a steam partial pressure of 3.5 bar
and a gas rate of 0.6 Nl gas mixture. (e catalyst) 1.h 1. The
catalyst was then extracted for two hours ~t 90C with stirring
with 40 l 2 N sulphuric acid which had been saturated with
sulphur dioxide. After the extracted catalyst had been washed
with water, it was dried at 120C and calcined for three hours
X~
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at 550C. On analysis Or the catalyst thus obtained (catalyst
D), 96% of the vanadium and 95% of the nickel were found to
have been removed from the catalyst by this treatment.
EXAMPLE IV
5 kg of Catalyst B was treated with a 5:1 steam/air mix
ture for 20 hours at 350C, a steam partial pressure of 3.0 bar
and a gas flow rate of 0.6 Nl gas mixture.(g catalyst) 1.h 1.
The catalyst was then subjected to acid extraction in the same
way as described in Example III. On analysis of the catalyst
thus obtained (catalyst E), 94% of the vanadium and 92% of the
nickel were found to have been removed from the catalyst by
this treatment.
EXAMPL V
5 kg of Catalyst B was treated with a 1:2 steam/air mix-
ture for 20 hours at 400C, a steam partial pressure of 0.6 bar
and a gas flow rate of 0.4 Nl gas mixture.(g catalyst) l.h 1.
The catalyst was then subjected to acid extraction in the same
way as described in Example III. On analysi3 of the catalyst
thus obtained (catalyst F), 95% of the vanadium and 95% of the
nickel were found to have been removed from the catalyst by
this treatment.
EXAMPLE VI
5 kg of Catalyst B was treated with a 2:1 steam/air mix-
ture for 25 hours at 150C, a steam partial pressure of 1.5 bar
and a gas ~low rate of 2 Nl gas mixture.(g catalyst) .h 1. The
catalyst was then subjected to acid extraction in the same way
8;2
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as de.scribed in Example ll`i. On analysis of the catalyst thus
obtained (catalyst C), 40~ of the vanadiu~ and 45g of the
nickel were found to have been removed from the catalyst by
this treatment.
EXAMPLE VII
Catalysts containing 0.5 pbw nickel and 2.0 pbw vanadium
per 100 pbw silica carrier were prepared by impregnating cata-
lysts C and F with an aqueous solution of nickel nitrate and
vanadyl oxalate, after which the compositions were dried and
calcined. Catalysts C' and F' thus obtained were used in the
sulphidic form for the hydrodemetallization of oil A under the
same conditions as the hydrodemetallization of this oil by
catalyst A dèscribed in Example I. The activities of catalysts
C' and F', expressed as "percentage vanadium removed", were 48
and 10, respectively.
EXAMPLE VIII
In the same way as described in Example VII, catalysts D'
and E' were prepared from catalysts D and E and usec for the
hydrodemetallization of oil A. The activities of catalysts D
and E', expressed as "percentage vanadium removed", were 50 and
49, respectively.
0f the examples I-VIII, Nos. III, IV and VIII are examples
according to the present invention. The other examples have
been included for comparison.
Example I relates to a hydrodemetalli~ation in which a
fresh catalyst A deactivates to the deactivated catalyst 3.
Example II relates to the three-stage procedure described
hereinbe~ore in which a regenerated catalyst C is prepared from
the deactivated catalyst B and in which it takes 53 hours in
all to carry out the first two stages~
Examples III and IV relate to the improved process accord-
ing to the invention in which regenerated catalysts D and E are
prepared from the deactivated catalyst B. Comparison of exam-
ples II, III and IV shows that the process according to the
invention leads to the same excellent metal removal as the
three-stage procedure. However, the treatment with the
steam/air mixture, which has replaced the first and the second
stage of the three-stage procedure, takes only 20-25 hours.
Examples V and Vl relate to the treatment of the deactiv-
ated catalyst with a mixture of steam and air followed by acid
extraction, in which "regenerated" catalysts F and G are pre-
pared from deactivated catalyst B. During the treatment with
the steam/air mixture. the steam partial pressure and the
steam/air ratio employed were too low in Example V and the
temperature was too low in Example VI. This resulted in an
2~ insufficient metal removal for catalyst G (and consequently in
a low activity!) and, as is seen from Example VII, in a low
activity for catalyst F.
From Examples VII and VIII it is seen that catalysts which
have been regenerated according to the present invention (cata-
lysts D' and E') show the same high activity as a catalyst
which has been regenerated according to the three-stage pro-
cedure (catalyst C').
