CA1094490A

CA1094490A - Process for demetallizing hydrocarbon oils

Info

Publication number: CA1094490A
Application number: CA277,004A
Authority: CA
Inventors: Dirk Bode; Robert H. Van Dongen; Jakob Van Klinken
Original assignee: Shell Canada Ltd
Current assignee: Shell Canada Ltd
Priority date: 1976-07-08
Filing date: 1977-04-26
Publication date: 1981-01-27
Also published as: SE421930B; NL7607552A; NL187026C; SE421930C; BE856187A; NO772401L; SE7707885L; FI65079B; DE2730565A1; IT1082115B; AU504664B2; JPH0122319B2; FR2357635A1; DK304177A; FI65079C; FI772119A; FR2357635B1; GB1560599A; DE2730565C2; JPS537704A

Abstract

A B S T R A C T

Hydrocarbon oils with a total vanadium and nickel content above 500 ppmw are demetallized by contacting them at elevated temperature and pressure and in the presence of hydrogen with a non-promoted catalyst which meets certain given requirements with respect to porosity and particle size.

Description

10~4~0 The present invention relates to a process for demetallizing hydrocarbon oils by contacting the oils with a catalyst at elevated -~
temperature and pressure and in the presence of hydrogen.
In Canadian Patent 1,005,777, issued February 22, 1977 to Shell Canada Ltd. catalysts are described which are promoted with one or more metals having hydrogenation activity and which meet the following re-quirements:
~1) p/d ~ 3.5-0.02 v, in which p is the specific average pore diameter in nm, d is the specific average particle diameter in mm and v is the percentage of the total pore volume that consists of pores with a diameter larger than 100 nm, ~2) the total pore volume is larger than 0.40 ml/g, (3) v is smaller than 50%, and (4) the specific surface area is larger than 100 m2/g; for the case that the catalyst has such a p and d that the quotient p/d is not larger than 10-0.15 v, the catalyst meets the following additional requirements:
(a) the nitrogen pore volume is larger than 0.60 ml/g, ~b) the specific surface area is larger than 150 m2/g, and ~c) p is larger than 5 nm.
According to aforementioned Canadian Patent 1,005,777 these catalysts are eminently suitable for use in the hydrodemetallization of metal-containing hydrocarbon oils.As was demonstrated in the exa~ples ; of said Canadian Patent, it is of vital importance for the catalysts to be promoted with one or more metals having hydrogenation activity (compare experiment 40 where a non-promoted catalyst was used for demetallizing an oil having a total vanadium and nickel content of 245 ppmw).
Continued investigation concerning the use of catalysts meeting the above-mentioned requirements with regard to porosity and particle - 30 size for the hydrodemetallization of hydrocarbon oils has shown that ; ~J - 2 -' 10~4~0 similar catalysts, but not promoted with one o~ mo~e metals having hydrogen~tion ~cti~ity, ~re neve~theless very suitable for this purpose, provided that the hydrocarbon oils concerned have a total vanadium and nickel content of more than 500 ppmw. Catalysts meeting the above-mentioned requirements with regard to porosity and particle size but not promoted with one or more metals having hydrogenation activity will, for the sake of brevity, in the present patent application further be designated: non-promoted catalysts.
The present invention therefore relates to a process for demetallizing hydrocarbon oils with a total vanadium and nickel content of more than 500 ppmw, the oils being contacted at elevated temperature and pressure and in the presence of hydrogen with a non-promoted catalyst meeting the following requirements:
, (1) p/d > 3.5-0.02 v, in which p is the specific average pore diameter in nm, d is the specific average particle diameter in mm and v is the percentage of the total pore volume that consists of pores with a diameter larger than lO0 nm,

(2) the total pore volume is larger than 0.40 ml/g, ~3~ v is smaller than 50%, and `~` 20 (~) the specific surface area is larger than 100 m2/g;
~. ~
;~ for the case that the catalyst has such a p and d that the quotient - p/d is not larger than 10-0.15 v, the catalyst meets the following ~` additional requirements:
(a) the nitrogen pore volume is larger than 0.60 ml/g, (b) the specific surface area is larger than 150 m2/g, and (c) p is larger than 5 nm.
~'. For further information concerning the determination of p and d reference is made to above-mentioned Canadian .:,~: .
1, 109~
,~,.,. .~, patent a~plicntion-.
Very suitable ~aterials to be used as catalysts in the process accordin~ to the invention are oxides of the elements of Groups I~, ~II and IV of the Periodic Table of Elements or ~lixtures of the said oxides, such as silica, alum~na, ma~nesia, zirconia, boria, silica-alurina, silica-magnesia and a umina-magnesia.
Anather type of material that is very suitable to serve as the catalyst in the process according to the invention is soot, in particular a soot obtained as a by-product in the partial oxidation of hydrocarbons with air, oxygen or mixtures of air and oxygen, either in the presence or in the absence of steam.
As catalysts for the process according to the invention aluminas, silicas and silica-aluminas are preferred. ~ery suitable catalysts are alumina or silica particles prepared by spray-drying of an alumina or silica gel, followed by shaping of the spray-dried micro particles into larger particles, e.~. by extrusion, and spherical alumina or silica particles obtained by the ~lell-known oil drop method.
The latter method comprises formation of an alumina or silica hydrosol, combining the hydrosol wlth a gelating agent and dispersing the mixture as droplets in an oil which may be kept at an elevated temperature; the droplet~
remain in the oil until they have solidified to form ; spherical hydrogel particles, which are subsequently separated, washed, dried and calcined. ~Tery suitable silica-10944~0 alumina catalysts are cogels of aluminium hydroxide gel on silica hydrogel.
The present catalysts may, inter alia, be shaped by extrusion or pelletizing. In addition to these shaping techniques especially the well-known nodulizing method is a very attractive shaping technique for the present catalysts. According to this method catalyst particles having a diameter of at most 0.1 mm are agglomerated with the aid of a granulation liquid to form particles having a diameter of at least 1.0 mm.
The demetallization activity of non-promoted catalysts according to the present patent application and of promoted catalysts according to aforesaid Canadian Patent 1,005,777 issued February 22, 1977 can be increased by the addition of hydrogen sulphide. Demetallization of heavy hydrocarbon oils with the aid of these catalysts is therefore preferably carried out with addition of hydrogen sulphide. In a further investigation concerning the influence of the addition of hydrogen sulphide when using the present non-promoted catalysts and promoted catalysts according to aforesaid Canadian Patent 1,005,777 for demetallizing heavy hydrocarbon oils ^, it was found that the effect of hydrogen sulphide greatly depends on the hydrogen partial pressure and the total pressure applied. When the point of view is taken that the use of hydrogen sulphide in the demetallization 2~ is economically attractive in particular when, at a given ~.

- ~) 10~4~0 total pressure, it results ln a gain in demetallization activity of more than 50~, then it is found that both for the non-promoted catalysts and for the promoted catalysts this requirement can be met if the quantity of hydro~en sulphide is chosen such that the quotient PH S/PH is equal to at least ~4 + ~ and at most 2P 60 (PH ~ PH S and PT represent the hydrogen partial pressure~
the hydrogen sulphide partial pressure and the total pressure in bar, respectively).
Within the limits set by the formula the demetallization activity of the catalysts reaches an optir,lum value at H2S H2S) The value of P*H is diff for the different catalysts and can be determined from some tentative experiments. Application of a PH S above or below P* but within the limits given still results in an increase of the demetallization activity by more than 50%, but this increase is smaller than the attainable maximum.
Obviously, during the demetallization process P*H S
or any other PH S may be controlled by continuously supplyin~
a sufficient quantity of hydrogen sulphide from an external source to the oil to be demetallized. However, from an economic point of view it is more attractive to utilize to the largest possible extent the hydrogen sulphide which is released in the demetallization process and/or in a desulphurization process to be carried out after the demetallization process. This consideration led to 7 1094~i9 the following three attractive embodiments of the demetallization process according to the invention in the presence Or additlonal hydrogen sulphide.
1) Application of gas recirculation ln the demetallization proeess~ the largest possible portion of hydrogen sulphide being left in the recirculating gas until the desired PH S is reached A certain auantity of hydrogen sulphide is thereuponcontinuously removed from the recirculating gas to maintain the desired hydrogen sulphide concentration.
2~ In partieular when a high P~ S is desired, it may take a considerable time beore the hydrogen sulphide eoneentration in the recirculating gas has reached the desired value. This difficulty can be met by supplying hydrogen sulphide from an external source during the initial stage of the process and gradually redueing the supply of hydrogen sulphide as the proeess advanees.
This additional quantity of hydrogen sulphide may, for instanee, eome from a hydrodesulphurization process.

3) Instead of gas recirculation to the demetallization reaetor or in combination with it, offgas from a desulphurization reactor installed after the demetallization reaetor is used as the feed gas for the demetallization ; 25 reaetor. A proeess seheme for a combined demetallization/
desulphurization process in the presence of hydrogen, whieh seheme is based on the aforementioned principle, - 8- 109449c~

is hown in the attached figure and is further elucidated hereinafter.
The plant comp1~ises successively a hydrodemetallization unit (1), a first gas-liquid separation unit (2), a hydro-desulphurization unit (3), a second gas-liquid separation unit (4) and a unit for the removal of hydrogen sulphide (~

4 ~etal-and-sulphur-containing residual hydrocarbon oil (~) is subjected to hydrodemetallization together with two hyd:^ogen- and hydrogen-sulphide-containing gas streams (7) and (8) and, if desired, with a hydrogen sulphide stream (9) from an external source. The product so obtained (10) is separated into a low-metal liquid stream (11) and a hydrogen- and hydogen-sulphide-containing gas stream (7), the latter being recycled to the demetallization unit.
Liquid stream (11) is subjected to hydrodesulphurization together with a hydrogen-containing gas stream (12) and a hydrogen stream (13) from an external source. The product so obtained (14) is searated into a low-metal and low-sulphur liquid stream (15) and a hydrogen- and hydrogen-sulphide-con-taining gas stream (16), the latter being split into two portions (8) and (17) of the same composition. Por~ion (8) is recycled to the demetallization unit and nortion (17), after removal of hydrogen sulphide, is recycled to the desulphuriza'ion unit as a gas stream (12).
The process according to the invention is preferably carried out by passing the hydrocarbon oils at elevated - 9 1094~0 temperature and pressure and in the presence of hydrogen in an upward, a do~nward or a radial direction through one or more vertically disposed reactors containing a fixed or moving bed of the catalyst particles concerned.
The process may, for instance, be carried out by passing the hydrocarbon oils together with hydrogen through a vertically disposed catalyst bed in an upward direction, the liquid and gas velocities applied being such as to cause the catalyst bed to expand (processing in ebullated bed operation). A veryattractive embodiment of the process is one in which the hydrocarbon oil is passed through a vertically disposed catalyst bed, in which during operation fresh catalyst is periodically introduced at the top of the catalyst bed and spent catalyst is withdrawn at the bottom thereof (processing in bunker flow operation).
Another very attractive embodiment of the process is one in which several reactors each containing a fixed ~atalyst bed are used, which reactors are alternately used for the process concerned; while the process is carried out in one or more of these reactors, the catalyst in the other beds is replenished (processing in fixed-bed swing operation). Tf desired, the process may also be carried out by suspending the catalyst in the hydrocarbon oil to be treated (processing in slurry phase operation).
The present catalysts are preferably used in the form of particles having a d of 0.5-4.0 mm and in particular ., - 10 - 1(~94~90 of o.6--3.0 mm.
The process according to the invention is preferably carried out at a temperature of 350-450C, a hydrogen partial pressure of 25-200 bar and a space velocity of 0.1-10 kg.kg l.h 1. Special preference should be given to the following conditions: a temperature of 375-425C, a hydrogen partial pressure of 50-150 bar and a space velocity of 0.5-5 kg.kg l.h 1 Hydrodemetallizi`ng of metal-con-taining hydrocarbon oils is particularly important if the oil is subsequently subjected to catalytic cracking, hydrocracking or hydrodesulphurization. As a result of the hydrodemetallization deactivation of the catalysts used in these processes is suppressed to a considerable extent. Hydrocracking and hydrodesulphurization of hydrocar-bon oils may be carried out by contacting the oils at elevated temperature and pressure and in the presence ~, of hydrogen with a suitable catalyst which may be present in the form of a fixed bed, a moving bed or a suspension of catalyst particles. An attractive combination of demetal-lization accoding to the invention and hy~rocracking or hydrodesulphurization is one in which the demetallization is carried out in fixed-bed swing operation or in bunker flow operation, while hydrocracking or hyArodesulphuri-zation is carried out in conventional fixed-bed operation.
Examples of hydrocarbon oils having a total vanadium and nickel content of more than 500 ppmw which are eligible ~0~4~n for demetallization according to the invention are crude oils and residues obtained in the distillation of crude oils such as topped crude oils, long residues and short residues.
The invention will now be elucidated with the aid of the following examples.
EXAMPLE I
Residual hydrocarbon oil having a total vanadium and nickel content of 1250 ppmw, which oil had been obtained after topping and dewatering of a crude oil from South America, was catalytically hydrodemetallized using six different non-promoted catalysts. To this end the oil, together with hydrogen, was passed downwards through a cylindrical vertically disposed fixed catalyst bed at a temperature of 410 C, a hydrogen-partial pressure (measured at the reactor inlet) of 150 bar, a space velocity of 2.1 kg of fresh feed per kg of catalyst per hour and a gas rate of 1000 Nl H2/kg of fresh feed. The liquid reaction product was split into two portions of the same composition in a volume ratio of 22:1. The smaller portion was removed from the system and the larger portion was recycled to the reactor inlet.
The results of the demetallization experiments to-gether with the properties of the catalysts applied have been collected in Table A. For determining p and v as well as -the total and nitrogen pore volumes, use was made of the nitrogen adsorption/desorption method and of the mercury penetration method, asmentioned in Canadian patent 1,005,777 issued February 22, 1977 to Shell Canada Ltd.

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s, . ..
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~: ~, I O oo o o C~
bO ~ 1 ll Il 1~
~ ~ ,, ~ I ~ J ~~~~
ll ,, o o ~oCOL~\

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l l "
ll 31~\Ir~3 ~ L~ , I
~a I "

ll 1~: 1 1 1 3t~ 0 11 I I
,, ll O F~ bO I ao 00 0 U~
~ Q. 0 ~1 1 Il p ~ I O O O O O O ~, , ~ ~ .
E~ ,, vl a) ~ I I I
h ~ ~ I Ir~ J oIr~ o r- 11 ~ O ~ ~ I o~ ~ ~ ~ "
E~ O ~ I O o o o o o 11 ,, l l ~)1 11 J I ~ O~`J 0 3 0 11 u~l ll l l ll ll ~ ll ~ l o ll ~11 ¢
I N O OC~l O
t~I O (~ ~ O t~J O 11 V~ ¢ ~ V~ ~ V~ I I
ll l l I :, O
X Z I ~1 ~ ~3 .Is~ w 1 11 .

109~0 ";

The performance Or the catalysts is assessed on ~ax and k1-5- ~max i 6 the maximum quantity of vanadium, expressed in %w on fresh catalyst, which the catalyst particles can absorb in the::r pores and k1 5 is the activity of the catalyst, expressed in kg.kg 1.h (ppmw V) 2, after half the catalyst life (in terms of quantity of vanadium absorbed) has elapsed. k1 5 is calculated with the formula k1 5 = (space velocity in k~.kg 1.h 1) x p~mw V in feed - ppmw V in product (ppmw V in product)1~
The performance of a catalyst is rated good under the conditions applied in this demetallization if the criteria I are met that ~Tmax is larger than 30 %w and that k1 5 is larger than o. o8 kg.kg 1.n 1.(ppmw V) 2 .
Experiments 1 and 2 in which the above requirements with respect to V~ax and k1 5 were satisfied, are demetal-lization experiments according to the invention. In Experi-ment 1~ in which a catalyst was used with 10-0.15 v > p/d ~
- 20 3.5-0.02 v, this catalyst also met the additional reauirements of the invention wi~h respect to total pore volume (> 0.40 ml/g), v (< 50%), nitrogen pore volume (> 0.0 ml/g), surface area (~ 150 m2/g) and p (~ 5 nm). In Experiment 2~ in which a catalyst was used with p/d ~ 10-0.15 v, this catalyst also met the additional requirements of the invention with respect to total pore volume (> 0.40 ml/g), v (c 50%) and surface area (> 100 m2/g).

~` - 14 - lO 9 ~ ~ 9 O

Experiments 3-6, in which the above requirements with respect to Vmax and k1 5 were not met, are demetal-lization experiments outside the scope of the present invention. In Experiment 3 a catalyst was used with 10-0,15 ~ p/d ~ 3.5-0,02 v, but with a nitrogen pore volume of less than 0.60 ml/g. In Experiment 4 a catalyst was used with 10-0.15 v > p/d > 3,5-0.02 v, but with a surface area of less than 150 m2/g, In Experiment 5 a catalyst was used with p/d ~ 10-0.15 v, but with a total pore volume of less than 0.40 ml/g. In Experiment 6 a catalyst was used with p/d < 3.5-0.02 v.
EXAMPLE II
Experiment 1 of Example I was repeated several times, each time with application of a different hydrogen su]phide partial pressure. In these experiments hydrogen sulphide was added from an external source. In all experiments a constant total pressure (measured at the reactor inlet) of 150 bar was applied. The results of these experiments have been collected in Table B.

" - 1 5 - ~0~ ~490 Table B
Exp. P~12,P7rl2S' k1.5' C7ain -1 -1 in kl,5, No. barbar (ppmw ~ %
---_____ 1 150 0 0.13 7 148 2 0.16 23 8 142 8 0.21 62 , 9 130 20 0.29 123 ~ -:
.;! 1 0 1 0 9 0 60 0.20 54 ========================_=_=========================
In Experiments 8-10 a PH S/PH was applied satisfyin~
the relation ., ~ ~ ~ PH ~/PH ' 2PT 60 and a gain in demetallization activity of more than 50% was reached. In Experiment 7 a PH2s/~H2 was applied which did not satisfy the above-mentioned relation .,,~, .
c, and a gain in demetalli.zation activity was obtained :~
.` 20 :. which was smaller than 50%.

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.

Claims

C L A I M S

1. A process for demetallizing hydrocarbon oils, characterized in that a hydrocarbon oil with a total vanadium and nickel content of more than 500 ppmw is contacted, at elevated temperature and pressure and in the presence of hydrogen, with a non-promoted catalyst meeting the following requirements:
(1) p/d > 3.5-0.02 v, in which p is the specific average pore diameter in nm, d is the specific average particle diameter in mm and v is the percentage of the total pore volume that consists of pores with a diameter larger than 100 nm, (2) the total pore volume is larger than 0.40 m1/g, (3) v is smaller than 50%, and (4) the specific surface area is larger than 100 m2/g;
for the case that the catalyst has such a p and d that the quotient p/d is not larger than 10-0.15 v, the catalyst meets the following additional requirements:
(a) the nitrogen pore volume is larger than 0.60 m1/g, (b) the specific surface area is larger than 150 m2/g, and (c) p is larger than 5 nm.

2. A process according to claim 1, characterized in that as the catalyst is used an oxide of an element of Group II, III or IV or a mixture of the said oxides.

3. A process according to claim 2, characterized in that as the catalyst silica, alumina or silica-alumina is used.

4. A process according to any one of claims 1-3, characterized in that catalysts are used having a d of 0.5-4.0 mm and preferably of 0.6-3.0 mm.

5. A process according to any one of claims 1-3, characterized in that it is carried out in bunker flow operation or in fixed-bed swing operation.

6. A process according to claim 1, characterized in that it is carried out with addition of hydrogen sulphide.

7. A process according to claim 6, characterized in that it is carried out in the presence of such a quantity of hydrogen sulphide that the quotient PH2S/PH2 satisfies the relation:

, where PH2 , PH2S and PT represent the hydrogen partial pressure, the hydrogen sulphide partial pressure and the total pressure in bar, respectively.

8. A process according to claim 6 or 7, characterized in that in the pro-cess use is made of hydrogen sulphide which is released in the demetallization process and/or in a desulphurization process to be carried out after the de-metallization process.

9. A process according to claim 7, characterized in that in the process use is made of hydrogen sulphide which is released in the demetallization pro-cess and/or in a desulphurization process to be carried out after the demetel-lization process, and in that gas recirculation is applied in the demetallization process, the largest possible portion of hydrogen sulphide being left in the recirculating gas until the desired PH2S is reached, after which a certain quantity of hydrogen sulphide is continuously removed from the recirculating gas to maintain the desired hydrogen sulphide concentration.

10. A process according to claim 9, characterized in that during the initial stage of the process hydrogen sulphide from an external source is supplied to the process and that the quantity of the hydrogen sulphide supplied is gradually reduced as the process advances.

11. A process according to claim 8, characterized in that a metal and a sulphur containing residual hydrocarbon oil is subjected to hydrodemetallization together with two hydrogen- and hydrogen-sulphide-containing gas streams (A and B) and, if desired, with a hydrogen sulphide stream from an external source, that the product obtained is separated into a low-metal liquid stream and a hydrogen-and hydrogen-sulphide-containing gas stream, the latter being recycled as gas stream A to the demetallization reactor, that the low-metal liquid stream together with a hydrogen-containing gas stream (C) and a hydrogen stream from an external source are subjected to hydrodesul-phurization, that the product obtained is separated into a low-metal and low-sulphur liquid stream and a hvdrogen- and hydrogen-sulphide-containing gas stream, the latter being split into two portions of the same composition, that one of these portions is recycled to the demetallization reactor as gas stream B and that the other portion after removal of hydrogen sulphide is recycled to the desulphurization reactor as gas stream C.

12. A process for the catalytic conversion of metal-containing hydro-carbon oils by cracking, hydrocracking or hydrodesulphurization, the oil first being demetallized and then being catalytically converted, characterized in that the demetallization is carried out according to any one of claims 1-3.

13. A process according to claim 1, characterized in that it is carried out at a temperature of 350-450°C, a hydrogen partial pressure of 25-200 bar and a space velocity of 0.1-10 kg.kg-1.h-1.

14. A process according to claim 13, characterized in that it is carried out at a temperature of 375-425°C, a hydrogen partial pressure of 50-150 bar and a space velocity of 0.5-5 kg.kg-1.h-1.