Note: Descriptions are shown in the official language in which they were submitted.
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The Canadian application 233,512 filed August 15, 1975 relates to a
process for extracting vanadium from a catalyst which has been de-
activated by use in the treatment of 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 10 pbw. According to the said application
233,512 the extraction of the vanadium, whereby the
vanadium content of 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-containi~g 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 increased as well, nickel is
also removed from 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 ext/action 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
rirst with steam to remove sulphur and then with an oxygen-con-
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taining gas to remove carbon, prior to subjecting it to acid
extraction. It should be remarked that, when the aim is not
only to extract 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 of the said application
233,512 whereby a small portion of the deactivated cata-
lyst 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 iq 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 issubjected 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 metals which are present on
the deactivated catalyst and the conditions chosen, viz. treat-
ment temperatures, gas flow rates and compositions of treating gases
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, . . .
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 result can be obtained as regards vanadium
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 is preceded by treatment of the deactiv-
ated catalyst with steam at a temperature above 250C and a
pressure above 1.5 bar. In addition to the fact that with the
process now foknd a much shorter treatment time will suffice
for achieving a comparable result as regards vanadium removal
and activity of the regenerated catalyst, this process has
three additional advantages over the above-mentioned
three-stage procedure in that the number of treatment stages
preceding the acid extraction has decreased by one, the number
of gases required for treating the deactivated catalyst prior
to acid extraction has been reduced to one and a reducing agent
is no longer used in the acid extraction.
The present patent application therefore relates to an
improved process for extracting vanadium from a deactivated
catalyst according to the application 233,512
in which process vanadium is extracted from a catalyst
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which has been deactivated by use in the treatment of a vanadium-
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 vanadium extraction, whereby the vanadium content of the
catalyst is reduced by at least 40% of the amount by which it has
risen during tne deactivation (vanadium content of the catalyst
expressed in pbw vanadium/100 pbw catalyst carrier), is carried
out by extracting the deactivated catalyst with an a~ueous sol-
ution 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
is preceded by a treatment of the deactivated catalyst with steam
at a temperature above 250C and a pressure above 1 5 ~ar.
According to the present invention there is provided
an improved process for extracting vanadium from a deactivated
catalyst which has been deactivated by use in the treatment of a
vanadium=containing hydrocarbon oil with hydrogen at elevated
temperature and pressure, during which treatment the vanadium
content of the catalyst increases by at least 10 pbw, said process
comprising subiecting the deactivated catalyst to steam at a
temperature above 250C and a pressure above 1 5 bar, and then
carrying out acid extraction by extractin~ the deactivated catal-
yst with an aqueous solution of a mineral acid after which the
vanadium is separated from the vanadium_containing solution thus
obtained, the vanadium content of the catalyst being reduced ~y at
least 40% of the amount by which it rises during said treatment,
the vanadium content of the catalyst being expressed in pbw
vanadium/100 pbw catalyst carrier.
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Preferably subjection of the deactivated catalyst to
steam takes place at a temperature below 550C and more prefer-
ably between 325 and 1125C.
Preferably the steam treatment should be performed at
a pressure below 10 bar and in particular between 2 and 7 bar.
The acid extraction to which the deactivated catalyst
should be subjected in the process according to the invention,
is preferably carried out at elevated temperature, in particular
at a temperature above 50C. The acid extraction is preferably
conducted with an aqueous solution of sulphuric acid.
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In the catalytic hydrotreatment of hydrocarbon oils at ele-
vated temperature and pressure, carbon is deposited on the catalyst
during the initial period until a certain carbon content has been
reached, after which the carbon content of the catalyst remains
practically constant during the further course of the operation.
When the results of the process now proposed are compared with
those of the three-stage procedure discussed hereinbefore, it
is found that carbon removal as in the three-stage procedure
does not take place now. It also appears that catalysts re-
generated according to the present invention, in spite of the
carbon present on them, have an activity comparable to that of
carbon-free catalysts which have beer regenerated according to
the three-stage procedure. If desired, one may remove carbon
from the catalysts also in the process according to the in-
vention by treating the catalysts after the acid extraction at
elevated temperature with an oxygen-containing gas. In com-
parison with the second stage of the three-stage procedure, in
which carbon is also removed from the catalyst, the treatment
with an oxygen-containing gas, optionally to be included in the
proce~s according to the invention, i5 a much simpler step,
because the amount Or heat released in this treatment is much
smaller.
In the catalytic hydrotreatment at elevated temperature
and pressure of the hydrocarbon oils containing nickel besides
vanadium, nickel is also deposited on the catalyst. Comparison
of the results of the process now proposed with those of the
three-stage procedure discussed hereinbefore shows that nickel
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is removed to a lesser extent now than in the three-stage
procedure. It is also found that catalysts regenerated accord-
ing to the present invention, in spite of the nickel present on
them, have an activity comparable to that of practically
nickel-free catalysts which have been regenerated according to
the three-stage procedure. If desired, one may remove more
nickel from the catalysts in the process according to the
invention. This can very suitably be done by treating the
regenerated catalyst first at elevated temperature with an
oxygen- containing gas and then subjecting it again to an acid
extraction.
Hydrocarbon oils which contain nickel beside~ vanadium and
which in the hydrotreatment at elevated temperature and pres-
sure cause both vanadium and nickel deposition on the catalyst,
contain as a rule much more vanadium than nickel. The quantity
of nickel deposited on the catalyst is therefore as a rule only
a fraction of the quantity of vanadium deposited. When a cata-
lyst is alternately used for hydrotreating a vanadium- and
nickel-containing hydrocarbon oil at elevated temperature and
pressure and is regenerated according to the invention, the
nickel content may in the long run build up to an undesirably
high value. This can be prevented in the regeneration by sub-
jecting a slipstream of the regenerated catalyst successively -~
to a treatment with an oxygen-containing gas at elevated tem-
perature and an acid extraction. The catalyst slipstream from
which the nickel has been removed is then added to the main
stream of the regenerated nickel-containing catalyst. The
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process according to the invention in which nickel build-up on
the catalyst is prevented by subjecting a slipstream of the
regenerated catalyst to an additional treatment may also be
carried out as follows. The regenerated catalyst is subjected
at elevated temperature to a treatment with an oxygen-contain-
ing gas for the removal of carbon. From the catalyst thus
treated a slipstream is separated, which is subjected to an
acid extraction. The catalyst slipstream from which nickel has
been removed is then added to the main stream of the
nickel-containing catalyst from which carbon has been removed.
The process according to the present 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 for catalytic
purposes, either as such, or after a complementary quantity of
metals with hydrogenation activity has been added to it. The
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 used in a
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process 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 impregnating a
silica carrier with an aqueous solution 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
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 space 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
process, it was extracted 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.
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EXAMPLE II
5 kg of Catalyst B was treated with a 4:1 steam/nitrogen mix-
ture 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 1:9 air/nitrogen mixture for 50 hours at
400C, atmospheric pressure and a gas flow rate of 1 Nl gas mix-
ture.(g catalyst) 1.h 1. ~inally, 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
thus 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 steam for five hours
at a temperature of 350C, a pressure of three bar and a space
velocity of 2.6 kg steam.(kg catalyst) 1.h 1. The catalyst was
then extracted for two hours at 90C with stirring with 40 l 2
N sulphuric acid. After the extracted catalyst had been washed
with water it was dried at 120C. On analysis of the catalyst
thus obtained (catalyst D), 95% of the vanadium and 45~ of the
nickel were found to have been removed from the catalyst by
this treatment.
EXAMPLE IV
5 kg of Catalyst B was treated in much the same way as in
Example III, but now the steam treatment was conducted at a
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temperature of 425C. On analysis of the catalyst thus obtained
(catalyst E), 90% of the vanadium and 60~ of the nickel were
found to have been removed from the catalyst by this treatment.
EXAMPLE V
5 kg of Catalyst B was treated in much the same way as in
Example III, but now the steam treatment was conducted at a
pressure of 6 bar. On analysis of the catalyst thus obtained
(catalyst F), 93% of the vanadium and 57% of the nickel were
found to have been removed from the catalyst by this treatment.
EXAMPLE VI
5 kg Or Catalyst B was treated in much the same way as in
Example III, but now the acid extraction was conducted for one
hour with 20 l 4 N sulphuric acid. On analysis of the catalyst
thus obtained (catalyst C), 96% of the vanadium and 60% of the
nickel were found to have been removed from the catalyst by
this treatment.
EXAMPLE VII
= . . ~ =
5 kg of Catalyst B was treated in much the same way as in
Example III, but now the acid extraction was conducted for one
hour with 20 l 6 N sulphuric acid. On analysis of the catalyst
thus obtained (catalyst H), 96~ of the vanadium and 75~ of the
nickel were found to have been removed from the catalyst by
this treatment.
EXAMPLE VIII
5 kg of Catalyst D which, like catalysts B, E, F, G and H,
contained 9.7 pbw carbon per 100 pbw silica, was treated with a
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1:5 airtnitrogen mixture for 10 hours at 400C, atmospheric
pressure and a gas flow rate of 1 Nl gas mixture.(g cata-
lyst) 1.h 1. Analysis of the catalyst thus obtained (cata-
lyst I) showed that it contained only 0.1 pbw carbon per 100
pbw silica.
EXAMPLE IX
5 kB of Catalyst I was extracted for two hours at 90C
with 5 l 2 N sulphuric acid. After the extracted catalyst had
been washed with water it was dried at 120C and calcined for
three hours at 550C. Analysis of the catalyst thus obtained
(catalyst J) showed that relative to the deactivated catalyst B
99% of the vanadium and 99% of the nickel had been removed from
the catalyst.
E MPLE X
5 kg of Catalyst B was treated in much the same way as in
Example III, but now the steam treatment was conducted at a
temperature of 200C and a pressure of 4 bar. On analysis of
the catalyst thus obtained (catalyst K), 46% of the vanadiun
and 35% of the nickel were found to have been removed ~rom
the catalyst by this treatment.
_ AMPLE XI
5 kg of Catalyst B was treated in much the same way as in
Example III, but now the steam treatment was conducted at a
pressure of 0.5 bar. On analysis of the catalyst thus obtained
(catalyst L), 71% of the vanadium and 43% of the nickel were
found to have been removed from the catalyst by this treatment.
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EXAMPLE XII
5 kg of Catalyst ~ was treated in much the same way as in
Example III, but now the steam treatment was conducted at a
pressure of 1.0 bar. On analysis of the catalyst thus obtained
(catalyst M), 80% of the vanadium and 43% of the nickel were
found to have been removed from the catalyst by this treatment.
EXAMPLE XIII
A catalyst containing 0.5 pbw nickel and 2.0 pbw vanadium
per 100 pbw silica carrier was prepared by impregnating cata-
lyst C with an aqueous solution of nickel nitrate and vanadyl
oxalate, after which the composition was dried. The catalyst C'
thus obtained was used in the sulphidic form for the hydrode-
metallization of oil A under the same conditions as the hydro-
demetallization of this oil with catalyst A described in
Example I. The activity of catalyst C', expressed as "% vana-
dium removed", was 48.
EXAMPLE XIV
Catalysts containing 1.0 to 2.8 pbw nickel and 2.0 pbw
vanadium per 100 pbw silica carrier were prepared by impregnat-
ing catalysts D, E, F, G, H and I with an aqueous solution of
vanadyl oxalate, after which the compositions were dried.
Catalysts D', E', F', C', H' and I' thus obtained were used for
the hydrodemetallization of oil A in the same way as described
in Example XIII. The activities of catalysts D', E-, F', G', H'
and I', expressed as "% vanadium removed", were 47, 48, 49, 48,
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49 and 51, respectively.
EXAMPLE XV
_ _
In the same way as described in Example XIII catalyst J'
was prepared from catalyst J and used for the hydrodemetal-
lization of oil A. The activity of catalyst J', expressed as"percentage vanadium removed", was 51.
Of the Examples I-XV Nos. III-IX, XIV and XV are examples
according to the present invention. The other examples haie
been included for comparison.
Example I relates to a hydrodemetallization in which a
fresh catalyst A deactivates to the deactivated catalyst B.
Example II relates to the three-stage procedure described
hereinbefore 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-VII relate to the improved process according
to the invention in which regenerated catalysts D-H are pre-
pared from the deactivated catalyst B. Mutual comparison of
Examples II-VII shows that the process according to the
invention leads to the same excellent vanadium removal as the
three-stage procedure. However, the steam treatment at a pres-
sure above 1.5 bar, which has replaced the first and the second
stage of the three-stage procedure, takes only five hours.
Example VIII relates to the treatment with an oxygen-con-
taining gas at elevated temperature of the carbon- and
nickel-containing regenerated catalyst H, yielding catalyst I
from which the carbon has been removed. Example IX relates to
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the acid extraction of the nickel-containing regenerated cata-
lyst I, yielding catalyst J from which the nickel has been
removed.
Examples X-XII relate to the treatment of the deactivated
catalyst with steam followed by acid extraction, in which
"regenerated catalysts" K-M are prepared from deactivated
catalyst B. During the treatment with steam the temperature was
too low in Example X and the pressure too low in Examples XI
and XII. This resulted in an insufficient vanadium removal for
catalysts K-M (and consequently in a low activity!).
From Examples XIII-XV it is seen that catalysts which
have been regenerated according to the present invention (catalysts
D'-J ) show the same high activity as a catalyst which has been
regenerated according to the three-stage procedure (catalyst
C')-
