NO144635B - PROCEDURE FOR THE DEMETALIZATION OF A CATALYSTS WITH MUTUALLY ADAPTED AVERAGE VALUES FOR POREDIAMETERS, PARTICLE DIAMETERS AND PERCENTAGE VOLUME OF PORTS WITH DIAMETERS OVER 100 NM - Google Patents

Description

Norwegian patent document no. 138909 describes a method

by demetallisation of a residual hydrocarbon oil which must then be converted catalytically. According to <p>the patent, the demetallation is carried out by bringing the oil at elevated temperature and pressure and in the presence of hydrogen into contact with a catalyst comprising one or more metals with hydrogenation activity and supported on a carrier material, the catalyst satisfying a number of requirements in terms of particle diameter and porosity . In the preparation of the catalyst, the well-known nodulization method can be used.

In this method, catalyst particles or catalyst carrier particles with a diameter of no more than 0.1 mm are agglomerated into particles with a diameter of at least 1.0 mm by means of a granulation liquid.

Demetallisation catalysts of a similar type to the one mentioned above are known from Norwegian patent document no. 141654.

However, these are not produced using the aforementioned nodulization technique.

A further investigation of the demetallation of residual hydrocarbon oils using catalysts that satisfy the requirements in the aforementioned Norwegian patent document no. 138909 in terms of particle diameter and porosity showed that the activity of such catalysts produced using the nodulation method is strongly dependent on the proportion of their pore volume which consists of pores with a diameter over 50 nm. It has been shown that these catalysts have an optimal activity when this proportion of pore evolution

met is at least 0.3 ml/g.

The invention thus relates to a method for the demetallation of a hydrocarbon residual oil, which includes treatment of the oil at elevated temperature and pressure and in the presence of hydrogen,

in contact with a catalyst which has in common with previous catalysts for the purpose that it comprises one or more metals with hydrogenation activity supported on a support material,

that it has been produced using the nodulation method and that it satisfies the following requirements: (1) p/d > 3.5 - 0.02 v, where p is the specific average pore diameter in nm, d the specific average particle diameter in um and v the percentage share of the total pore volume that is made up of pores with a diameter greater than 100 nm.

(2) the total pore volume is greater than 0.40 ml/g,

(3) v is less than 50, and

(4) the specific surface area is greater than 100 m 2 /g, when the catalyst has such a p and d that the quotient p/d is greater than 3.5 - 0.02 v, but at most 10 - 0.15 v, the catalyst must satisfy the following additional requirements:

(a) the nitrogen pore volume is greater than 0.60 ml/g,

(b) the specific surface area is greater than 150 m 2 /g, and (c) p is greater than 5 nm.

The new method is characterized by the fact that the demetallation is carried out in the presence of a catalyst in which the pore volume, which is made up of pores with a diameter of over 50 nm, is at least 0.3 ml/g.

As mentioned above, catalyst particles or catalyst carrier material particles with a diameter of no more than 0.1 / yes are agglomerated in the production of the catalyst using the nodulization method into particles with a diameter of at least 1.0 mm. by; using a granulation liquid. In practice, the production of the catalyst using the nodulation method takes place as follows: The catalyst support material with a diameter of

a maximum of 0.1 mm is placed on a rotating disc which is provided with raised edges and with a scraping device. The disc is

arranged at a particular angle in relation to the horizontal plane. A granulation liquid is sprayed onto the carrier material which is kept in continuous motion on the disc. If aluminum oxide is used

as a carrier material, in practice, as a rule, a diluted

aqueous solution of acetic acid or citric acid is used as granulation liquid. While the small particles are on ski-

ven, larger particles of these are formed due to agglomeration. The nodulation method can be carried out batchwise or continuously. When the continuous process is used, a finely dispersed material is continuously supplied to the rotating disk, and agglomerated material is continuously removed from the disk via the top of the raised edge when this is in its lowest position. After the agglomerated particles have been removed from the disc, a sieve fraction with the desired diameter is separated from these. Particles with a diameter smaller than that of the particles in the desired sieve fraction can be recycled to the disc. If the agglomerated material contains particles with a diameter that is larger than the diameter of the particles in the desired sieve fraction, these particles can, after the particle size has been reduced, e.g. when grinding down, is also recycled to the disc. The conversion of the agglomerated material with the desired particle size into a suitable carrier material is carried out by drying and calcination. The placement of one or more metals with hydrogenation activity on a carrier material thus produced is usually carried out by impregnation with an aqueous solution of compounds of the metals in question, followed by drying and calcination of the impregnated material.

In the present method, catalysts comprising 0.1 - 15 parts by weight of one or more metals with hydrogenation activity per 100 parts by weight, carrier material. The metals with hydrogenation activity preferably consist of nickel, cobalt, molybdenum or vanadium. It is also preferred that the catalysts comprise at least one of the metals nickel and cobalt and at least one of the metals molybdenum and vanadium and furthermore that the atomic ratio between nickel bg/or cobalt j3 on the one hand and molybdenum and/or vanadium on the other hand is between 0.05 and 3.0. Suitable metal combinations are nickel-vanadium, cobalt-molybdenum and nickel-molybdenum. The amount of metals with hydrogenation activity in the catalysts is preferably 0.5 - 10 parts by weight, preferably 2.0 - 7.5 parts by weight, per 100 parts by weight carrier material. Particularly preferred demetallization catalysts are catalysts comprising approx.

0.5 parts by weight of nickel and approx. 2 parts by weight of vanadium per 100 parts by weight carrier material, and also catalysts comprising approx.

1 part by weight of nickel or cobalt and approx. 4 parts by weight molybdenum per

100 parts by weight carrier material. The metals can be present on the carrier material in metallic form or as oxides or sulphides. It is preferred to use catalysts in which the metals are present on the support material in the form of sulphides. The catalysts can be sulphided by any method known in the art for sulphiding catalysts.

Suitable carrier materials for the catalysts used according to the invention are oxides of the elements in group II, III or IV of the periodic table or mixtures of these oxides, such as silicon oxide, aluminum oxide, magnesium oxide, zirconium dioxide, silicon dioxide-aluminium oxide and silicon dioxide-magnesium oxide. If one of the above-mentioned oxidic carrier materials is used for the production of the catalysts, it is preferred for this purpose to use aluminum oxide or silicon dioxide. Another type of material which is very well suited for use as a carrier material for the catalysts is carbon black, and in particular carbon black obtained as a by-product from the partial oxidation of hydrocarbons with air, oxygen or mixtures of air and oxygen and possibly in the presence of water vapour. Besides the fact that carbon black is suitable as a carrier material for the demetallization catalysts used according to the invention, the use of carbon black for this purpose entails a further advantage which is not obtained by using any of the above-mentioned oxidic carrier materials. This can be explained as follows: Although the catalysts used for the implementation of the present method have a long life when demetallizing hydrocarbon residues, even these catalysts will in the long run be deactivated due to the deposition of large amounts of metals, especially vanadium and nickel, and they must therefore be replaced after a certain period of operation. If it is intended to recover the deposited metals from the deactivated catalyst, the use of a catalyst on carbon black as carrier material will have the significant advantage over catalysts on other carrier materials that the carrier material can simply be removed from the deactivated catalyst by combustion, after which a mixture of the relevant metals is returned in the form of oxides for further processing.

When investigating the production of demetallisation catalysts using the nodulation method, it was

found five embodiments of the common method, each of which will give a beneficial effect. These embodiments will be described in more detail below. 1. In the production of catalysts based on aluminum oxide as carrier material, an aqueous solution of acetic acid or citric acid is usually used as a granulation liquid. It has been shown that when diluted nitric acid is used as granulation liquid, aluminum oxide-based catalysts can be obtained with a crushing strength and density that is considerably higher than when an aqueous solution of citric acid or acetic acid is used. 2. When, in the manufacture of the catalyst, the starting material is mixed with a certain amount of glass powder and the particles formed using the nodulation method are also calcined at a temperature above the softening temperature for glass, catalysts with a considerably increased crushability can be obtained. The amount of glass powder used is preferably 0.5 - 15% by weight based on the amount of starting material with which it is mixed. 3. When phosphorus is incorporated into the catalysts, their activity during the demetallation of hydrocarbon residues will be increased considerably. The incorporation of phosphorus into the catalysts can take place during any step in the manufacture of the catalysts. Thus, the incorporation of phosphorus can e.g. advantageously carried out by adding a phosphorus compound to the granulation liquid and/or to the impregnation liquid which is supplied for applying the metals with hydrogenation activity to the particles formed. The amount of phosphorus compound is preferably chosen so that a catalyst is obtained comprising 0.5 - 5% by weight of phosphorus per 100 parts by weight carrier material. 4. In the production of catalysts using the nodulation method, larger particles that are more or less spherical are formed from the starting material. The size of the particles formed is, among other things, variable depending on the residence time of the material on the rotating disc. After the particles have approximately reached the desired size, they are removed from the disk and dried and calcined. It has

it has been found that catalysts of a considerably higher density can be produced when the formed particles after they have been removed from the rotating disk, but before drying and calcining, are rotated for a certain time, e.g. in a rotating drum. Such a rotation of the formed particles is preferably carried out for a time which at least corresponds to the residence time of the material on the rotating disk.

5. In the manufacture of the catalyst by the nodulation method, the usual procedure is to dry and calcine the carrier material particles after they have been formed on the disc, followed by an application of the desired metals with hydrogenation activity to the calcined material, e.g. by impregnation with an aqueous solution of salts of the metals in question.' Finally, the impregnated material is dried and calcined. It has been found that this catalyst preparation can be greatly simplified by introducing

the metal salts in the granulation liquid. When the metals are applied to the catalyst in this way, the separate impregnation step and also the second drying step and the calcination step can be omitted, and this of course implies a significant saving in the production of the catalysts i-.tek-. national scale.

Examples of suitable water-soluble metal compounds which can be used in the production of the catalysts used for carrying out the present method are nitrates, chlorides, formates and acetates of nickel and cobalt, ammonium molybdate, vanadyl oxalate, vanadyl sulphate and vanadyl acetylacetonate and ammonium vanadate.

Catalyst particles are preferably used for the catalytic hydrodemetallisation of hydrocarbon residual oils using the present method. with a d. of 1.0 - 4>0 mm, especially 1.5 - 3.5 mm.

If, in carrying out the present method, a catalyst is used with such a p and d that the quotient p/d is greater than 10 - 0.15 v, it is preferable to choose a catalyst with a total pore volume of at least 0.50 ml/g and a specific one

surface area of over 150 m^/g.

The invention will be described in more detail by means of

the example below..

Example

A hydrocarbon residual oil with a total vanadium and nickel content of 62 parts per million (ppm), a C^-asphaltene content of 6.4% by weight and a sulfur content of 3.9% by weight and is

kept as a residue during distillation at atmospheric pressure of a crude oil from the Middle East (oil B according to Norwegian patent document no.

13-8909, was catalytically hydrodemetallated at different volume rates and using five different catalysts. For this purpose, the oil together with hydrogen was passed downwards through a cylindrical, vertically arranged, solid catalyst bed at a temperature of 420° C., a total pressure of 150 bar and an off-gas quantity of 250 NI H 2 Ag new feed material. The catalysts were used in the form of their sulfides.

The production of the five catalysts that were used for the demetallization experiments, and also of three other catalysts by carrying out the present method and which had been produced using the nodulation method, is described below. The results of the demetallization experiments, the volume velocities used and the properties of the catalysts are reproduced in

the table.

Catalyst production

Catalyst A

As starting material, an aluminum oxide obtained by spray drying and with a d of less than 0.09 mm was used. The aluminum oxide had a -pore volume of- 1.2 ml/g which consisted of pores with a diameter of over 50 nm. 100 g of this aluminum oxide was poured onto a rotating disc, and 100 ml of an aqueous solution containing 3.5 g of citric acid was gradually sprayed onto the aluminum oxide. The rotating disk, which was provided with a raised edge of a height of 10 cm, had a diameter of 40 cm. The disc rotated 40 times per minute and was arranged at an angle of 45° in relation to the horizontal plane. After a residence time of 15 minutes, the formed nodules were removed from the disc. After drying at 120° C. bla a. sowf raks ion jned a d of 2.0 mm separated from the dried material. After calcination in 1

hour at 600° C, the particles were impregnated with an aqueous solution comprising nickel nitrate and ammonium molybdate. The impregnated material was finally dried at 120° C and calcined for 1 hour at 500° C. The thus produced catalyst comprised 1 part by weight of nickel and 4 parts by weight of molybdenum per 100 parts by weight aluminum oxide.

Catalyst B

The catalyst was prepared in essentially the same way as catalyst A, but with the difference that 100 ml of an aqueous solution comprising 3.5 g of nitric acid was used as granulating liquid.

Catalyst C

The catalyst was prepared in essentially the same way as catalyst A, but with the difference that for catalyst C, 2 g of glass powder with a d less than 0.09 mm was added to the aluminum oxide starting material and that after the calcination at 600° C, a further calcination was carried out for 1 hour at 800° C.

Catalyst D

The catalyst was prepared in essentially the same way as catalyst C, but with the difference that for catalyst D so much NH^I^PO^ was added to the impregnation liquid comprising nickel and molybdenum that a catalyst was obtained which, in addition to 1 part by weight of nickel and 4 parts by weight molybdenum contained 1 part by weight of phosphorus per 100 parts by weight aluminum oxide.

Catalyst E

The catalyst was prepared in essentially the same way as catalyst C, but with the difference that for catalyst E, after being removed from the disc, the nodules were rotated for a further 1 hour in a rotating drum.

Ka talysator F

The catalyst was prepared in essentially the same way as catalyst A, but with the difference that for catalyst F the starting material was an aluminum oxide obtained by spray drying and with a pore volume of 0.36 ml/g which consisted of pores with a diameter of over 50 nm.

Catalyst G

The starting material was carbon black with a diameter of less than

0.1 mm and with a pore volume of 0.58 ml/g which consisted of pores with a diameter of over 50 nm. The soot had been obtained as a by-product from the partial oxidation of hydrocarbons with air. The soot was present as a slurry in water and was isolated from this by filtering, drying the filter cake and grinding down the dried

material to the aforementioned particle size. The nodules were produced from the soot in essentially the same way as the nodules produced from aluminum oxide as described in connection with catalyst A, but with the difference that for catalyst E an aqueous solution of lignosulfonate was used as granulating liquid. After a residence time of 15 minutes, the nodules were removed from the disc. After drying at 120° C., a sieve fraction with a diameter of 1.8 mm was separated from the dried material. After calcination for 1 hour in a stream of nitrogen at a temperature of 700° C., these particles were impregnated with an aqueous solution comprising nickel nitrate and vanadyl oxalate. The impregnated material was finally dried at 120° C and calcined for 1 hour at 500° C in a stream of nitrogen. The catalyst produced in this way contained 0.5 parts by weight of nickel and 2 parts by weight of vanadium per 100 parts by weight of soot.

Catalyst H

The catalyst was produced in essentially the same way as catalyst G, but with the difference that for catalyst H the starting material was carbon black obtained as a by-product from the partial oxidation of hydrocarbons with air and with a pore volume of 0.26 ml/g which consisted of pores with a diameter of more than 50 nm, and that the nodules formed after being removed from the disk were rotated for a further 1 hour in a rotating drum.

All catalysts listed in the table are catalysts that can be used according to Norwegian patent document no. 138909. Catalysts A - E, G and H with p/d <>> 10.0 - 0.15 v also satisfy the other requirements according to the aforementioned patent document as regards v(<50%), total pore volume (>0.40 ml/g) and specific surface area (>100 m<2>/g). The catalyst F with 10.0 - 0.15 v > p/d > 3.5 - 0.02 v also satisfies the other requirements according to the patent document regarding v(<50 %), p(>5 nm), nitrogen pore volume (> 0.60 ml/g) and specific surface area

(>150 m<2>/g).

Of the catalysts listed in the table, catalysts A - E and G which were produced using the nodulation method, and which have a pore volume of at least 0.2 ml/g which is made up of pores with a diameter of over 50 nm, are catalysts which can be used according to the present invention. Catalysts F and H, even if they were prepared by means of the fiodoulization method, but have a pore volume of less than 0.2 ml/g which is made up of pores with a diameter of more than 50 nm, fall outside the scope of the present invention. They have been included in the table for comparison.

A comparison between the crushing strength and density for catalysts A and B shows the beneficial effect of using dilute nitric acid as granulating liquid instead of an aqueous citric acid solution.

The beneficial effect of incorporating glass powder into the starting material, together with calcination at a temperature above the softening temperature of glasses is evident from a comparison of the crush strength of catalysts A and C.

A comparison of the density for catalysts C and E shows the beneficial effect of a post-rotation of the nodules after they have obtained the desired size, on the rotating disc.

According to Norwegian patent document no... 1389.09

catalyst under the conditions used for the present demetallization experiments, satisfy the condition that the catalysts must still be able to remove over 40% by weight of the total amount of vanadium and nickel in oil B after 5 tonnes of this oil have been treated over the catalyst with a volume velocity of at least 2.9 1.1 "*".h ^.

All the experiments given in the table (where the catalysts satisfy the above-mentioned requirements for the removal of Ni+V by weight%) are metal removal experiments within the scope of Norwegian patent document no. 138909. ^v the experiments given in the table are experiments 1, 2 and 4 (in which the catalysts -respectively C, D and G were used) demetallation test according to the present invention. Experiments 3 and 5 (in which the catalysts F and H were used respectively) fall outside the scope of the present invention. They have been included for comparison.

The influence of the catalyst's pore volume, which is made up of pores with a diameter of over 50 nm, on the catalyst's demetallization activity is evident from a comparison of the results for experiments 1 and 2 with the results for experiment 3, and from a comparison of the results for experiment 4 with the results for experiment 5. It has been shown that the catalysts C and D (in which the pore volume is above 0.20 ml/g) are still able to remove resp. 50 and 55 wt% V+Ni after treatment of 5 tonnes of feed material per kg of catalyst at a volume rate of 4.6 1.1 1. h_ while the catalyst F (in which the pore volume is below 0.20 ml/g) is only able to remove 41 wt% V+Ni after treating the same amounts of feed material per kg catalyst, while moreover the volume rate is only 3.0 1.1 \h A similar situation exists for catalysts G and H. Catalyst G (in which the pore volume is above 0.20 ml/g) is still able to remove 51 wt% V +Ni after processing 5 tonnes of feed material per kg catalyst at a volume rate of 3.1 1.1 ^t h. 1, while the catalyst H (where the pore volume is below 0.20 ml/g) is only able to remove 42 wt% V+Ni after treating the same amount of feed material per kg of catalyst at the same volume rate.

A comparison of the demetallisation activities for catalysts C and D shows the beneficial effect of the incorporation of phosphorus in the catalysts.

Claims (6)

1. Process for the demetallation of a hydrocarbon residual oil, which includes treatment of the oil at elevated temperature and pressure and in the presence of hydrogen in contact with a catalyst, comprising one or more metals with hydrogenating activity on a carrier material, using a catalyst that has been prepared using the nodulation method and which satisfy the following requirements: (1) p/d >3.5 - 0.02 v, where p is the specific average pore diameter in nm, d the specific average particle diameter in mm qg v the percentage of the total pore volume constituted by pores with a diameter greater than 100 nm, (2) the total pore volume is greater than 0.40 ml/g, (3) v is less than 50, and (4) the specific surface area is greater than 100 m2/g, when using a catalyst with a p and d such that the quotient p/d is greater than 3.5 - 0.02 v, but no more than 10 - 0.15 v, the catalyst must further satisfy the following requirements: (a) the nitrogen pore volume is greater than 0.60 ml/g, (b) the specific surface area is greater than 150 m 2/g, and (c) p is greater than 5 nm, characterized in that the demetallation is carried out in the presence of a catalyst in which the pore volume, which is made up of pores with a diameter over 50 nm, is at least 0.3 ml/g. 2. Method according to claim 1, characterized in that the demetallization is carried out in the presence of a catalyst obtained by mixing the starting material from which larger particles are formed using the nodulation method with a certain amount of glass powder, and by the particles formed using the nodulation method being calcined at a temperature above the softening temperature for glass. 3. Method according to claim 2, characterized in that the added amount of glassr powder is 0.5 - 15% by weight based on the amount of the starting material with which it is mixed. 4. Method according to claims 1-3, characterized in that the demetallization is carried out in the presence of a catalyst comprising phosphorus, preferably in an amount of 0.5 - 5% by weight per 100 parts by weight carrier material. 5. Method according to claims 1-4, characterized in that the demetallization is carried out in the presence of a catalyst obtained by the formed particles being post-rotated for a certain time after they have been removed from the rotating disc, but before drying and calcination, preferably in a time which at least corresponds to the residence time of the material on the rotating disk. 6. Method according to claims 1 - 5, characterized in that the demetallization is carried out in the presence of a catalyst with a specific average particle diameter of 1.0 - 4.0 mm and preferably 1.5 - 3.5 mm.