NL8201962A - CATALYST SUITABLE FOR HYDRODE METALLIZATION OF HEAVY FEEDS AND METHOD FOR HYDRODIDE METALLIZATION OF HEAVY FEEDS. - Google Patents

Description

N.0. 31,078 s? t l

Catalyst suitable for heavy feed hydrodemetallization and process for heavy feed hydrodemetallization.

The invention relates to a process for the catalytic hydrotreating of heavy hydrocarbon fractions and in particular to alumina catalysts used in such a process.

Porous alumina has often been used as a support material for various hydroprocessing catalysts for hydrocarbonaceous materials. When the feed is more or less free of soluble metal impurities, such as iron, nickel, vanadium and the like, ordinary porous alumina is generally satisfactory as a catalyst support. However, if the feed contains high concentrations of soluble metal impurities, in a conventional alumina treatment catalyst there is a tendency for metals to rapidly accumulate near the mouth of the pores, thereby clogging the pores of the catalyst and its activity is reduced. Since regenerating a catalyst by metal removal is generally impractical, the useful life of a conventional alumina catalyst is limited to the time required to clog the pores.

20 Due to declining oil supplies throughout the world, the oil processing industry is facing the need to use feeds which are highly contaminated with metals. In the treatment of these feeds, it is extremely desirable to remove the contaminant metals as much as possible in the refining of these feeds as early as possible, so that other hydroprocessing catalysts used subsequently do not suffer from metal build-up and thereby reduced activity. The removal of metals also provides a better quality end product that is less corrosive and less polluting on combustion.

A variety of demetallization catalysts have been proposed, including many that are supported on a porous refractory inorganic oxide, such as aluminum oxide. U.S. Pat. No. 3,898,155 discloses a catalyst which has a wide range of pore sizes including a prescribed percentage pore size of more than 600ngstrom and an average pore size of more than 100 lb. which has a high content of 8201962 2 of catalytic metals # US patent 4 * 257 * 922 describes a hydroprocessing catalyst for hydrocarbonaceous material obtained from coal, which has bimodal pore distribution and high metal content.

US Patent 4 * 199 * 531 discloses a catalyst having pores with an average diameter of at least 125 lb, but no mention is made of the desirability of a substantial portion of the pore volume being supplied by large diameter pores.

The invention now provides a porous alumina catalyst suitable for the hydrodemetallization of hydrocarbonaceous feeds, having a calculated micropore diameter of at least 125 X a specific surface area of at least 100 ml / g and a pore volume of at least 0 1.5 cm / g, wherein at least 5% of the pore volume is contained in pores of more than 1000 lbs. And which contains no more than 6 wt.% Group VIB catalytic metals and no more than 3 wt.% Catalytic metals of group VIII. The catalyst of the invention is prepared by adding a sufficient amount of peptizer to an alumina slurry between 20 and 100 ° C and mixing. The peptized mass is neutralized with a solution of a nitrogenous base and a dissolved salt of a Group VIB transition metal compound is added. The mass is molded, then dried at 100 ° C to 260 ° C for 1 to 5 hours and then in a steam atmosphere at 450 to 825 ° C for 1 to 3 hours and then in a dry air atmosphere at 450 for 1 to 3 hours annealed to 825 ° C. Preferably, the peptizer is formic acid or acetic acid and the nitrogenous base is ammonia. Be a soluble salt of one. Group VIII metal can be added to the peptizing solution or to the neutralizing solution. A sufficient amount of a soluble salt of a Group VIB metal can be added to the peptizer or the neutralizing agent to contain 0.06 g of metal molecule per gram of dry Al 2 O0 in the finished catalyst. The invention is directed to the hydrodemetallization of feeds, which have a high content of soluble metal impurities and asphaltenes, by contacting the feeds with the catalyst under hydroprocessing conditions.

More particularly, the invention relates to a novel catalyst for the hydrodemetallization of hydrocarbon feedstocks containing a significant amount of metals. It has been found that a novel catalyst prepared from porous alumina and has the property that at least 3% of its pore volume contained in pores having diameters of more than 1000 X and having an average pore diameter of at least 125 X and a metal content of less than 6% is particularly good for metal removal which are present in hydrocarbonaceous feeds which are highly contaminated with metal-containing compounds, organic compounds.

Feeds which can be satisfactorily handled by this method can contain significant amounts of ingredients boiling above 3 ° C. They can contain metals in amounts of more than 1000 ppm and asphaltenes in amounts of at least as much as 25% by weight. Examples of such feeds are crude oils, topped crudes, residues from both atmospheric and vacuum distillation, oil obtained from tar sands and oil slates and residues of such oils and hydrocarbonaceous materials obtained from coal. Such feeds tend to contain large amounts of metal impurities, such as, but not limited to, iron, nickel and vanadium. are often found in the "asphalten" fraction of the feed * As defined herein, "asphaltene" denotes that fraction of any hydrocarbon feed which is not soluble in n-heptane regardless of whether this fraction is soluble in benzene is *. By removing the metals from the asphaltenes and other oil fractions, which may be contaminated with metals, the quality of the oil can be improved so that it can be further refined according to conventional oil refining techniques.

The catalyst composition, as prepared and used in the demetallization process of this invention, will have at least 5% of its pore volume, which is provided by pores greater than 1000X. The catalyst composition will have a nitrogen pore volume of at least 0.5 cm / g, having a nitrogen adsorption specific surface area of at least 100 m / g and an average pore diameter of more than 125 X. As used in this description, the average pore diameter is calculated from the pore volume in pores smaller than 1000X, according to the following equation: 8201962 4 k

Average pore diameter »k x PV (in pores of less than 1000 lb) x 10 ** specific surface area where the average pore diameter is expressed in Sngstrom,

-L

PV expressed by cm / g and the specific surface area expressed in m2 / g.

The catalyst composition of this invention will contain a catalytic hydrogenating component selected from group VIB of the periodic table (Handbook of Chemistry and Physics 51st edition). The concentrations of Group VIB metals should not exceed 6% by weight of metal based on the finished catalyst. A Group VIII hydrogenating metal component can be added and should not exceed 3 wt% of the finished catalyst. * The Group 15 VIB hydrogenating metal component is added as a soluble salt of the metal dissolved in an aqueous solution. of a nitrogenous base, for example, molybdenum oxide dissolved in an ammonium hydroxide solution. If no Group VIII metal is added to the support, but only a Group VIB metal, a soluble salt of a Group VIB metal can be added to the peptizer. An example of such a salt is phosphomolybdenum acid. If a Group VIII catalytic metal is to be added, it is added as a soluble salt dissolved in the peptizer, for example, cobalt acetate dissolved in formic acid.

Since most metals in heavy hydrocarbonaceous feeds are contained in large asphaltenic molecules, demetalization is a diffusion-limited process. A low metal content catalyst is believed to be more effective in removing metals from the feed because it has a reduced absolute activity, causing less deposition of metals near the mouth of the pores and the metal containing molecules in the feed are allowed to enter the interior of the catalyst particle. The lower activity ensures that metals will not settle prematurely near the mouth of the catalyst pores, clogging the pores and limiting access to the center of the particle. The total internal surface area of the catalyst particle can then be utilized for the deposition of metals from the feed 8201962 * This leads to a longer useful life of the catalyst. It was also observed that the calculated average pore diameter of catalyst compositions with higher metal contents tends to be less than that of catalysts with a lower metal content.

Since the accessibility of the interior of the catalyst particle is dependent on the pore size, catalysts of lower metal content but larger pores allow better access to the interior of the particles.

The catalyst of the invention is preferably prepared by peptizing needle-like alumina. An example of an alumina useful in the invention is Kaiser Substrate Alumina SD medium with a peptizer, for example, formic acid. Needle-like alumina is hereby defined as alumina, which has a microcrystalline structure similar to needles, in particular about 50 to 100 µl in length, which are stacked in a random orientation relative to one another.

Other aluminum oxides can be used to obtain the desired pore structure. An example of another suitable alumina is Catapal produced by Conoco, but this alumina does not have the needle-like microstructure. Another source of alumina is pre-annealed alumina, which is copeptized with non-annealed alumina.

The needle-like alumina is preferred because catalyst supports prepared therefrom tend to be more resistant to impact. It has been found that the catalyst according to the invention will have a compressive strength of more than 10 kg / cm.

When the peptized alumina has reached a homogeneous consistency at a pH between 3 to 6, it is neutralized again by adding an aqueous solution of the nitrogen-containing base. During peptizing and neutralization, the temperature is kept between 20 and 100 ° C.

The neutralized alumina is then shaped and dried. The molding can be carried out by any of various conventional techniques, such as extrusion, pelleting, ball molding and the like. Typical drying conditions are 100 to 200 ° C for 1 to 5 hours. The dried material is then calcined for 1 to 3 hours at b50 to 825 ° C in an IfO steam atmosphere and then 1/2 to 3 hours at the same temperature in a dry atmosphere. The higher the temperature at which the catalyst particles have annealed, the greater the average pore diameter tends to be.

The process of the invention uses generic hydrotreating conditions which include reactions within the temperature range of about 200 to 51 ° C, a total pressure within the range of about 1 atmosphere to about 300 atmospheres at a partial hydrogen pressure to about 200 atmospheres, a hydrogen to oil supply ratio of at most 9000 normal liters per liter of oil and a liquid space velocity of about 0.1 to about 25 reciprocal hours. The actual conditions depend on the composition of the feed, the purity of the product, expressed in desired permissible amounts of impurities, and the condition of the catalyst. The temperature can be slowly increased to reduce the natural deterioration of the activity of the catalyst. compensate if metals are deposited on this ·

The invention is particularly well suited for use in a two-stage demetallization / desulfurization process. In such a process, a sulfur and metal contaminated feed is passed over a bed of the catalyst of the invention at high temperature and under high pressure and then over a desulfurization catalyst under similar conditions. If the second catalyst is to have a long service life, it is decisive that as much metal as possible is removed in the first stage, because otherwise the particles of the desulfurization catalyst will lose their activity quickly. In practice, it is preferable to use a two-stage bed with one catalyst bed on top of the other in the same reaction vessel. Two catalyst beds so divided in stages are particularly effective in removing metals and sulfur from highly contaminated feeds, because the catalyst of the invention is particularly good at removing metals and the subsequent desulfurization catalyst will remove the sulfur from the demetallized oil remove.

Likewise, the catalyst of the present invention can be charged to a reactor and the subsequent desulfurization catalyst can be charged to a separate reactor so that these catalysts can be replaced individually when any of the catalysts become inactive.

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In a particularly preferred embodiment, the catalyst of the invention is kept at a higher temperature than the desulfurization catalyst, usually about 28 ° C higher. The demetallization catalyst is more active, whereby some of the metals from the feed is removed before it is desulfurized. Since the desulfurization catalyst is exposed to an oil from which a substantial amount of metals has already been removed, it has a high desulfurization activity even if it is kept at a lower temperature.

When the metal in the feed is removed, the metal deposits on the catalyst. The effectiveness of any catalyst to remove metals from a feed can be measured by a metal concentration profile, ie the concentration of the metals in percent, deposited on the catalyst, as a function of the fractional radius of the catalyst. sator particle. An average concentration of this metal on the catalyst, A, can be determined from the metal concentration profile. The concentration profile usually shows a peak in the bpurt 20 of the edge of the catalyst particle. This maximum concentration, M, and the mean concentration, A, are used to determine an effectiveness factor, E, as follows:

E - A E "M

The higher the effectiveness factor, the more desirable the demetallization catalyst. The metal concentration profile can be obtained using an electron beam probe. The micro probe sends a fine electron beam with a diameter of about 1 µm onto a catalyst particle, which is fixed in Bakelite, polished and coated with carbon. The beam causes the emission of characteristic X-rays from the metals from the prepared particle. The characteristic X-ray is identified and its intensity is measured. The concentration of the metal on the catalyst can be calculated from the X-ray intensity of this metal from the catalyst and the X-ray intensity of the same metal from a standardized sample containing known amounts of this metal. The micro probe analysis determines the metal concentration on a small surface on the catalyst. The analysis can be repeated at points along the IfO radius of the catalyst part to obtain 8201962 δ the concentration profile.

The access of different metals to the interior of the catalyst particle is believed to be diffusion controlled, so the effectiveness factors for different metals are therefore related to the size of molecules with which a particular metal is joined. In Table A, some vanadian effiency factors of different catalysts are compared with the effect of diameter on the effectiveness factor.

Table A

10 Catalyst Particle Diameter V Efficacy Factor A 1.59 0.31 B 1.59 0.60 C 1.02 0.8o D * 1.59 0.9if 15 * Trilobal Grooved Form. The particle diameter is twice the individual groove diameter.

Catalyst A is the desulfurization catalyst described in U.S. Patent 4,113,661, which disclosure is believed to be incorporated by reference. Catalysts B 20 to D are examples of the catalyst of the present invention with various geometric shapes. B and C are cylinders and D is a three-lobed grooved shape.

The effectiveness factor is a measure of how efficiently the total volume of the catalyst is used for demetallization. Good demetallization catalysts tend to have effectiveness factors close to: 1, while less effective catalysts have lower factors. * Knowledge of the effectiveness factor provides some insight into the potential service life of a catalyst. More effective catalysts tend to utilize the total catalyst volume effectively, while less effective catalysts tend to deposit most of the metals near the surface of the catalyst, clogging the mouths of the pores and the operating times of the catalysts are shortened.

If metals tend to deposit at some fairly constant distance from the surface of the catalyst particle, it will be appreciated that when the particles are made smaller, the efficiency ratio increases. This IfO method of increasing the effectiveness ratio leads to bed fillings of smaller catalyst particles, with the tendency for high pressure drops to occur, making them unsuitable for many applications in large-scale treatments.

The catalyst of the invention has a high effectiveness factor, at least 0.60 (when measuring the effectiveness of vanadium removal) for a cylindrical extruded particle with a diameter of 1.59 mm.

The following examples are illustrative and are not limitative.

Example I

This example illustrates the preparation of a catalyst support containing molybdenum at low levels.

8 ml of 88% formic acid (specific gravity 1 »2) was added to 300 ml of distilled water. This solution was added to 500 g of Kaiser alumina at about 50 ° C in such a way that about 50 ml per minute were added with mixing. Mixing was continued for 20 minutes after the entire solution was added. A second solution prepared from 6 ml of 58% ammonium hydroxide, k5 ® 1 of a molybdenum solution and 200 ml of distilled water was added with stirring at a rate of 50 ml / minute. The molybdenum solution was prepared by dissolving 17 g of MoO 2 in 17.2 ml of 30% NH 2 OH and 26 ml of distilled water. The temperature during the second addition was about 60 to 65 ° C. The doughy mixture was extruded using a three-lobed grooved die and dried on a sieve tray in a preheated oven at 0 ° C for 2 hours. It; 120 DEG C. and then 2 hours at 200 DEG C. of the extrusion product were calcined at 680 DEG C. in a steam atmosphere. After one hour, the steam was replaced with fresh dry air and the extrusion was annealed for another half an hour at 680 ° G.

Example II

This example illustrates the preparation of a catalyst containing both molybdenum and cobalt at low levels. 34.2 g of cobalt acetate [CoCC ^ HjOg ^ JfHgO] was added to 350 ml water. This solution was added to a solution of 15 ml of 88% formic acid (specific gravity 1.2) in 250 ml of distilled water to form solution A.

Solution B was prepared by mixing 12 ml of concentrated 58% ammonium hydroxide with 90 ml of a. molybdenum solution 40 and 1 ml of distilled water. The molybdenum solution was prepared 8201962

"X

by dissolving 34 8 g of MoO 4 in 34 4 ml of 30% NH 4 OH and 52 ml of distilled water.

1000 g of Kaiser alumina was peptized by adding solution A at 50 ° C over a period of 12 minutes with mixing. Mixing was continued for another 20 minutes after solution A was completely added. The pH of the aluminum oxide mixture was between 3 and 6. Then, 50 ml of solution B was added per minute and mixing was continued for 20 minutes after the addition was completed. The final temperature was 65 ° C. The mixture was then extruded through cylindrical nozzles and dried at 120 ° C for 2 hours and then at 200 ° C for 2 hours. The dried extrusion product was fired at 680 ° C in a steam atmosphere for 1 hour and then at 680 ° C in a dry air atmosphere for half an hour.

Example III

Example III shows the use of the catalyst of Example I in a hydrodemetallization process.

A sample of an Arabian heavy vacuum residue boiling above 402 ° C was contacted with the catalyst of Example 1 at a liquid space velocity of 1.5 reciprocal hours under a hydrogen pressure of 11.7 MPa at 404 ° C. Table B shows the difference in sulfur, nickel and vanadium concentration in the feed and in the effluent for the catalyst of Example 1 after it had been used for 500 hours.

25 Table B

S wt # Ni ppm V ppm

Supply 5 * 12 36 140

Effluent 3.6 25 75

The catalyst retained remarkably constant activity after an initial deactivation period. This catalyst, when extruded in the grooved form, had an efficiency factor of 0.94.

Example IV

A catalyst is prepared according to the general method of Example II except that a sufficient amount of metal salts are mixed into the alumina so that the finished calcined catalyst contains 3 1 wt.% Cobalt and 9 12 wt.% Molybdenum.

The properties of this catalyst and the catalyst of Example II are compared in Table C.

40 8201962 11

Table C

High content Low metal content of metaléh

Cobalt, wt $ 3.1 0.92 molybdenum, wt # 9.2 2.8 pore volume, ctsP / g 0.97 1.01% of pore volume provided by pores larger than 1000 A 26 18 -

Calculated micropore diameter, l 115 180 2

Specific surface o / g 250 184

It is noted that the higher the metal concentration, the calculated micropore diameter tends to be smaller and therefore less desirable for demetallization.

Example V

A reactor is filled with catalyst, one third of the total batch consisting of the catalyst according to the invention, which is extruded into round cylinders with a diameter of 1.59 mm. One third of the total catalyst charge of U.S. Patent 4,113,661. One third of the total 10 batch consists of a formed commercially available desulfurization catalyst, which is marketed by Ketjen as an asymmetric four-lobed catalyst * Arab heavy residue from the atmospheric distillation with 4.4 wt% sulfur, 26 ppm nickel and 89 ppm vanadium is contacted with these catalysts under technical hydroprocessing conditions. The first catalyst, which is present in what is here defined as the first zone, is placed on a. 28 ° C higher temperature than the second and third catalysts present in what is here defined as the second zone. The temperature was controlled to keep 0.6% sulfur in the product. When the first catalyst reached 427 ° C, it was kept at this temperature and only the temperature of the second and third catalysts was increased to meet the sulfur requirements * The end of the test was reached * when the temperature of the second and third the third catalysts reached 427 ° C. * The average product quality. of the effluent of the first zone and of the effluent of the second zone is monitored. The results are summarized in Table D.

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* V

12

Table D

Contamination Supply Effluent from the Effluent of the _____________ _ first zone second zone

Sulfur (wt. #) UA 2.8 0.6

Nickel (ppm) 26 16 9

Vanadium (ppm) 89 37 22

It has been found that the major part of the demetallization takes place on the demetallization catalyst of the invention. A useful life of 7 months has been demonstrated with this catalyst system. The middle catalyst layer, under the same pressure and space velocity, showed only a life of k months.

8201962

Claims (16)

1. Catalyst composition for the hydroprocessing of hydrocarbonaceous feeds, characterized by a formed aluminum oxide support having a calculated micropore diameter of at least 125 a specific surface area of at least 100 m / g; a pore volume of at least 0.5 cm3 / gi at least 5% of the pore volume provided by pores with a diameter of at least 1000 which contains no more than 6 wt% of a Group VIB catalytic metal if the weight percentage is based on the weight of the reduced metal relative to the total catalyst weight. 2. Catalyst composition according to claim 1, characterized by -15 having more than 3 wt% of a Group VIII metal, the weight percentage being based on the weight of the reduced metal relative to the total catalyst weight. Catalyst composition according to claim 1 or 2, characterized in that the aluminum oxide has a needle-like microstructure. if. Catalyst composition according to any one of the preceding claims, characterized in that the catalyst has a compressive strength of at least 10 kg / cm. Process for the hydrodemetallization of hydrocarbonaceous feeds, characterized in that the feed is contacted with hydrogen under hydroprocessing conditions in the presence of a catalyst on an aluminum oxide support with a calculated micropore diameter of at least 125 2 a specific surface area of at least 100 m / g; a pore volume of at least 0.5 cm / g; wherein at least 5% of the pore volume is provided by pores with a diameter of at least 1000 lb; 35 and containing no more than 6% by weight of Group VIB catalytic metals. 6. Process according to claim 5, characterized in that the catalyst contains no more than 3% by weight of a Group VIII metal. 8201962 V η Method according to claim 5 or 6, characterized in that the aluminum oxide support has a needle-like microstructure. 8. Process according to any one of claims 5 to 7, characterized in that the catalyst has a compressive strength of at least 10 kg / cm. 9. Catalyst for hydroprocessing hydrocarbonaceous feeds prepared according to the process characterized in that peptizing agent is added to alumina at a temperature between about 20 and 100 ° C to form a slurry with a pH between 3 and 6 ; the peptized alumina is neutralized with an aqueous solution of a nitrogenous base and a soluble compound of Group VIB transition metal to form a moldable plastic mass; the plastic mass is formed; the mass is dried at 100-200 ° C for about 1 to 5 nren; 20 and the dried mass is calcined at 450-825 ° C for about 1 to 6 hours. 10. A method according to claim 9, characterized in that the aluminum oxide has a failure-like microstructure. 11. A method according to claim 9, characterized in that at least a part of the aluminum oxide has been annealed beforehand. A method according to any one of claims 9 to 11, characterized in that the peptizer is formic acid. Method according to claim 9 *, characterized in that the peptizing agent contains at most 0.06 gram molecule of a Group VIII metal per gram molecule dry. 1Jf * Process according to any one of claims 9 to 13 », characterized in that the dried mass is annealed in a steam atmosphere for 1 to 3 hours at 825 ° C and then in a dry atmosphere for about 1/2 to 3 hours . Catalyst prepared according to the process of any one of claims 7 to 1f. 16. Catalyst for hydroprocessing to supply hydrocarbonaceous ifO prepared according to the process which has the characteristic 8201962 * V 'that peptizing agent is added to alumina at a temperature between about 20 and 100 ° C, which peptizing agent is a soluble salt of a transition metal of group VIB to form a suspension having a pH between 3 and 6; the peptized alumina is neutralized with an aqueous solution of a nitrogenous base to form a moldable plastic mass; the mass is formed; The mass is dried at 100-260 ° C for about 1 to 5 hours; and the dried mass is fired at 450-825 ° C for 1 to 3 hours. * 17 * The method according to claim 16, characterized in that the aluminum oxide has a needle-like microstructure. 18. Process according to claim 16 or 17, characterized in that at least a part of the aluminum oxide has been annealed beforehand. 19 * Method according to any one of claims 16 to 18, characterized in that the peptizing agent is formic acid. 20. Process according to any one of claims 16 to 19, characterized in that the peptizing agent contains at most 0.06 grams of molecule of a Group VIII metal per gram of molecule of dry A 2 O 2. Process according to any one of claims 16 to 20, characterized in that the dried mass is calcined in a steam atmosphere for 1 to 3 hours and then in a dry atmosphere at 450-825 ° C for half to 3 hours. A catalyst prepared according to the method of any one of claims 16 to 21 ****** 8201962