JPH0428419B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a process for the catalytic hydrotreatment of heavy hydrocarbon cuts, and in particular to an alumina catalyst used in this type of process. Porous alumina has often been used as a support material for various catalysts for hydroprocessing hydrocarbon feedstocks. If the feedstock does not contain significant amounts of soluble metal impurities such as iron, nickel, vanadium, etc., common porous alumina generally serves well as a catalyst support. However, if the feedstock contains high levels of soluble metal impurities, conventional alumina-based processing catalysts tend to rapidly accumulate metals near the pore openings.
It blocks the pores of the catalyst and reduces its activity. The lifetime of conventional alumina catalysts is
limited to the point at which pore blockage occurs. Due to the global oil supply shortage, oil refiners are faced with having to use feedstock oils that are high in metal contaminants. When refining these feedstock oils, by removing as much metal impurities as possible as early as possible, the catalyst used in the subsequent refining process will not accumulate metals and reduce its activity. It is highly desirable to do so. Removal of metal also provides a high quality final product with relatively low corrosion and contamination properties when burned. Various demetallization catalysts have been proposed, many of which are supported by porous, refractory inorganic oxides such as alumina. US Patent No.
The catalysts disclosed in No. 3,898,155 have a wide range of pore sizes, with a specified percentage of pore sizes greater than 600 Å, average pore sizes greater than 100 Å, and contain high concentrations of catalytic metals. US Pat. No. 4,257,922 describes a catalyst for the hydrotreatment of coal-derived hydrocarbon feedstocks with a bimodal pore distribution and high metal content. Although U.S. Pat. No. 4,199,531 describes catalysts having pores with an average diameter of 125 Å or more, it is desirable for a substantial portion of the pore volume to come from larger diameter pores. nothing is mentioned. a porous alumina catalyst suitable for hydrodemetallization of hydrocarbon feeds, having a calculated micropore diameter of at least 125 Å and a surface area of at least 100 m ² /g;
having a pore volume of at least 0.5 cc/g, at least 5% of the pore volume occupied by pores larger than 1000 Å, and not more than 6% by weight of a Group B catalytic metal and not more than 3% by weight of a Group B catalyst metal; catalytic metals are provided by the present invention. The catalyst of the present invention is
It is prepared by adding and mixing sufficient peptizing agent to a slurry of alumina at 20° to 100°C. The peptized mass is neutralized by adding a solution of a nitrogen-containing base and a salt of a Group B transition metal compound. The mass is shaped and dried at 100° to 260°C for 1 to 5 hours, then dried at 450° to 825°C in a steam atmosphere for 1 to 3 hours.
After baking, bake at 450° in a dry air atmosphere for 1-3 hours.
Bake at 825℃. Formic acid and acetic acid are preferred as peptizers, and ammonia is preferred as nitrogen-containing base. A soluble Group metal salt can be added to the peptizer or neutralizer solution. drying
Sufficient soluble Group B metal salt can be added to the peptizer or neutralizer to provide 0.06 g moles of metal per g mole of Al ₂ O ₃ in the finished catalyst. The object of the present invention is to hydrodemetallize a feedstock containing a large amount of soluble metal impurities and asphaltenes by contacting the feedstock with a catalyst under hydrotreating conditions. The present invention is a novel catalyst for the hydrodemetalization of hydrocarbon feeds containing substantial amounts of metals. Porous alumina is used as a raw material, at least 5% of the pore volume is occupied by pores with a diameter of 1000 Å or more, the average pore diameter is at least 125 Å, and the metal content is 6% or less. It has been discovered that a new catalyst is extremely effective in removing metals from hydrocarbon feeds containing large amounts of metal-containing and organic compounds as contaminants. Feedstocks that can be effectively treated by this method may contain substantial amounts of components with boiling points of 540°C or higher. These feedstocks may contain 1000 ppm or more of metals and 25% by weight or more of asphaltenes. Examples of such feedstocks include crude oil, extracted crude oil, residual oils from atmospheric and vacuum distillation, oils from tar sands and oil shale and their residual oils,
Also included are hydrocarbon materials derived from coal. This type of feedstock oil tends to contain large amounts of metal contaminants. Examples of such metal contaminants include, but are not limited to, iron, nickel, and vanadium. These metals are often found in the "asphaltenes" fraction of feedstocks.
As used herein, the term "asphaltenes", whether or not soluble in benzene,
Refers to all hydrocarbon feed fractions that are insoluble in n-heptane. Removal of metals from asphaltenes and other oil fractions containing metals as contaminants improves the quality of the oil and allows for further purification by conventional oil refining techniques. The catalyst produced by the method of the invention and used in the demetalization process has at least 5% of its pore volume
is derived from pores of 1000 Å or more. The catalyst composition has a nitrogen pore volume of at least 0.5 cc/g and a surface area measured by nitrogen adsorption of at least
100 m ² /g and the average pore diameter is greater than 125 Å. In this specification, the average pore diameter is calculated from the pore volume contained in pores of 1000 Å or less according to the following formula: Average pore diameter = 4 × pore volume (of pores of 1000 Å or less )×10 ⁴ /surface area (where the average pore diameter is expressed in Å and the pore volume is
cc/g and surface area in m ² /g). The catalyst composition of the present invention is suitable for use in periodic table [Handbook of Chemistry and Physics] No. 51
The catalyst component for hydrogenation is selected from Group B of the following. The Group B metal concentration should be no more than 6% metal by weight of the finished catalyst. Group hydrogenation metal components can be included in amounts up to 3% of the finished catalyst. The Group B hydrogenation metal component is added as a soluble metal salt dissolved in an aqueous solution of a nitrogenous base, such as by dissolving molybdenum oxide in an ammonium hydroxide solution. If no Group metal is added to the support and only Group B metal is added, a soluble Group B metal salt may be added to the peptizer. An example of this type is molybdate. If a Group catalytic metal is added, it is added as a soluble salt dissolved in a peptizer, such as gobalt acetate dissolved in formic acid. Because most of the metals in heavy hydrocarbon feeds are contained in large asphaltene molecules, demetallization is a diffusion limited process.
process). It is considered that a catalyst with a low metal content is more efficient in removing metals from feedstock oil, but the reason for this is that the absolute activity
This is thought to be because the amount of metal deposited near the pore openings is small due to the low activity), and the metal-containing molecules in the feedstock can easily approach the interior of the catalyst particles. The low activity prevents premature metal deposition near the pore openings, thereby avoiding pore clogging and blocking access to the particle center.
Therefore, the entire internal surface of the catalyst particles can be utilized as a metal deposit bed from the feedstock. As a result, the life of the catalyst is extended. It has also been found that metal-rich catalyst compositions tend to have smaller calculated average diameters than metal-poor catalysts. The difficulty in approaching the inside of catalyst particles depends on the pore size, so if the catalyst has a low metal content but large pores, the feedstock oil can easily come close to the inside of the particles. The catalyst of the present invention is preferably prepared by peptizing acicular alumina. An example of an alumina useful in the present invention is Kaiser Substrate Alumina SD-normal grade;
An example of a peptizer is formic acid. As used herein, "acicular" alumina refers to a microcrystalline structure in which needles, typically 50 to 100 Å in length, are stacked on top of each other in a random jackstraw orientation. It is defined as alumina with Other aluminas can also be used to obtain the desired pore structure. Another suitable example of alumina is Catapal from Conoco, which does not have an acicular microstructure. Other alumina sources are
This is a pre-calcined alumina that undergoes peptization treatment at the same time as calcined alumina. It is preferable to use acicular alumina because catalyst supports made from acicular alumina tend to be more resistant to crushing. It was confirmed that the crushing strength of the catalyst of the present invention was 10 kg/cm or more. Once the peptized alumina has a homogeneous consistency of pH 3 to 6, an aqueous solution of a nitrogenous base is added to return it to neutrality. During peptization and neutralization,
Keep the temperature between 20° and 100°C. Next, the neutralized alumina is shaped and dried. Shaping can be accomplished by any of several conventional techniques, including extrusion, tabletting, spheronization, and the like. Typical drying conditions are 100° to 260°C for 1 to 5 hours. Next, the dried material is heated to 450° to 825° C. in a steam atmosphere for 1 to 3 hours, and then heated to the same temperature in a dry atmosphere for 1/2 to 3 hours to perform an oxidation treatment. The higher the firing temperature, the larger the average pore diameter of the catalyst particles tends to be. The method of the present invention uses general-purpose hydrogen treatment conditions, such as a temperature range of about 200° to 540°C, a total pressure of about 1 to 300 atm, a hydrogen partial pressure of up to about 200 atm, and up to a standard of 9000 for 1 part oil. hydrogen to oil supply ratio of, and approximately
Reaction conditions consisting of liquid hourly space velocities of 0.1 to about 25 h ^-1 are employed. The exact conditions will depend on the composition of the feedstock, the purity of the desired product in terms of acceptable contaminant content, and the condition of the catalyst. The temperature is gradually increased to compensate for the natural decrease in catalyst activity as the metal is deposited. The present invention is particularly suitable for use in two-stage demetalization/desulfurization processes. In this type of method, a feed oil containing sulfur and metals as impurities is passed over the catalyst of the present invention at high temperature and pressure, and then passed over a desulfurization catalyst under the same conditions. If it is desired to maintain a long life of the second catalyst, it is necessary to remove as much metal as possible in the first step, otherwise the desulfurization catalyst particles will be rapidly deactivated. In practice, it is desirable to have two beds in the same reaction vessel, one catalyst bed above the other. Such two-stage catalyst beds are particularly effective in removing metals and sulfur from feedstocks containing large amounts of contaminants because:
This is because the catalyst of the present invention is particularly effective in removing metals, and sulfur is removed from the demetallized oil by the subsequent desulfurization catalyst. Alternatively, the catalyst of the present invention can be loaded into one reaction column and the subsequent desulfurization catalyst can be loaded into another reaction column, so that when one of these catalysts becomes deactivated, each can independently generate a new one. It may be possible to replace the catalyst. In particularly preferred embodiments, the catalyst of the present invention is maintained at a higher temperature than the desulfurization catalyst, typically about 28°C higher. By keeping the demetallization catalyst active, a portion of the metal is removed before the feedstock is desulfurized. Since the desulfurization catalyst is brought into contact with the oil after a substantial amount of metal has been removed, its desulfurization activity is high even though the desulfurization catalyst is kept at a relatively low temperature. As metals in the feedstock are removed, they are deposited on the catalyst. The efficiency of metal removal from a feedstock by any catalyst can be measured by the metal concentration profile, i.e., the percentage concentration of metal deposited onto the catalyst as a function of the fractional radius of the catalyst particles. . From the metal concentration profile, the average concentration A of the metal on the catalyst can be determined. Usually the concentration profile shows a peak near the edges of the catalyst particles. Using this maximum concentration M and average concentration A, the effectiveness coefficient E is determined as follows: E=A/M The higher the effectiveness coefficient, the more preferable the demetalization catalyst is. This metal concentration profile can be determined using an electromicroprobe. A microprobe sends an ultrafine electron beam about 1 micron in diameter onto catalyst particles set in polished, carbon-coated Bakelite. This beam causes X-rays characteristic of metals to be emitted from the sample particles. This unique X-ray is identified and its intensity is measured. The metal concentration on the catalyst can be calculated from the X-ray intensity of the metal obtained from the catalyst and the X-ray intensity of the metal obtained from a sample containing a known amount of the metal. This microprobe analysis measures metal concentrations in small areas on the catalyst. The analysis is repeated at each point along the radius of the catalyst particle to determine the concentration profile. Since the phenomenon of proximity of various metals into the interior of catalyst particles is considered to be diffusion controlled, the effectiveness coefficients for various metals are related to the size of the molecules associated with any particular metal. The table is
A comparison of some of the effectiveness factors for vanadium of various catalysts and the effect of diameter on the effectiveness factor.

Table: Catalyst A is a desulfurization catalyst described in US Pat. No. 4,113,661, which is incorporated by reference herein. Catalysts BD are examples of geometrically different catalysts of the invention. B and C are cylindrical, and D is trefoil-shaped. The effectiveness factor is a measure of the efficiency with which the total capacity of the catalyst is utilized for demetallization. A good demetalization catalyst will have an effectiveness factor close to 1, while a less efficient catalyst will have a lower coefficient. Knowing the effectiveness factor can predict the potential life of the catalyst. A highly effective catalyst utilizes the entire catalyst volume efficiently, whereas a less effective catalyst deposits most of the metal close to the surface of the catalyst, thereby blocking the pore openings and blocking the catalyst. shorten the lifespan of It can be seen that if the metal has a tendency to deposit at a certain distance from the surface of the catalyst particles, the effectiveness ratio increases when the particles are made smaller. Such methods of increasing efficiency ratios result in bed packing with small catalyst particles, resulting in large pressure drops that are unsuitable for many applications with large scale operations. The catalyst of the present invention has a high effectiveness factor of at least 0.60 (as measured by vanadium removal effectiveness) for extruded cylindrical particles having a diameter of 0.0625 inches. The examples set forth below are for illustrative purposes and are not intended to limit the invention. Example 1 This example shows the preparation of a catalyst support containing low levels of molybdenum. 8 ml of 88% formic acid (specific gravity 1.2) was added to 300 ml of distilled water. The above liquid was added to 500 g of Kaiser alumina at a rate of about 50 ml per minute at about 50° C. while mixing was continued. Mixing was continued for 20 minutes after all solutions had been added. A second solution prepared with 6 ml of 58% ammonium hydroxide, 45 ml of molybdenum solution and 200 ml of distilled water was added under stirring at a rate of 50 ml per minute. 30%
The above molybdenum solution was prepared by dissolving 17.4 g of MoO ₃ in 17.2 ml of NH ₄ OH and 26 ml of distilled water. Second
The temperature of the second addition was about 60° to 65°C. The dough-like mixture was extruded using a trilobal flute die and dried on a screen tray in a preheated oven at 120°C for 2 hours and then at 200°C for 2 hours. The dried extrudates were calcined at 680°C in a steam atmosphere. After 1 hour, the steam was replaced with fresh dry air and calcination was carried out at 680° C. for an additional 1/2 hour. The fine structure of the catalyst of this example is as follows. That is, molybdenum
3.2% by weight, pore volume 0.97 cc/g, pore volume >1000 Å 17%, surface area 191 m ² /g and calculated micropore diameter 168 Å. Example 2 This example describes the production of a catalyst containing low levels of both molybdenum and cobalt. 34.2g
of cobalt acetate [Co(C ₂ H ₃ O ₂ ) ₂・4H ₂ O] at 350
ml of water. Solution A was prepared by adding the above solution to a solution of 15 ml of 88% formic acid (specific gravity 1.2) dissolved in 250 ml of distilled water. Solution B is obtained by mixing 12 ml of 58% concentrated ammonium hydroxide with 90 ml of molybdenum solution and 400 ml of distilled water.
shall be. This molybdenum solution contains 34.4ml of 30%
It was prepared by dissolving 34.8 g MoO ₃ in NH ₄ OH and 52 ml distilled water. Solution A was added to 1000 g of Kaiser alumina while mixing at 50° C. for 12 minutes to perform peptization treatment. After the addition of Solution A was complete, mixing was continued for 20 minutes. The pH of the alumina mixture was 3-6. Solution B was then added at a rate of 50 ml per minute and mixing continued for 20 minutes after the addition was complete. The final temperature was 65°C. The mixture was then extruded through a cylindrical die, dried at 120°C for 2 hours, and then at 200°C for 2 hours. The dried extrudates were calcined for 1 hour at 680°C in a steam atmosphere and then 1/2 hour at 680°C in a dry air atmosphere. Example 3 In Example 3, Example 1 in the hydrodemetalization process
This shows the use of catalysts. A sample consisting of Arabic heavy vacuum distillation residue oil with a boiling point of about 900〓 ⁺ or higher was heated at a liquid time-space velocity of 1.5 h ^-1 ,
Contact was made with the catalyst of Example 1 at a hydrogen pressure of 1700 psi and a temperature of 404°C. The table shows the changes in the concentrations of sulfur, nickel and vanadium in the feedstock and in the effluent from the catalyst of Example 1 obtained after 500 hours of slow rotation.

[Table] After the initial deactivation period, the activity of the catalyst remained very constant. The effectiveness coefficient of this catalyst when extruded into a vertical groove was 0.94. Example 4 Example 2 except that sufficient metal salts were comulled into the alumina to provide 3.1% by weight cobalt and 9.2% by weight molybdenum in the catalyst after final calcination. The catalyst is prepared by the general method of A comparison of the properties of this catalyst and the catalyst of Example 2 is shown in the table.

【table】

TABLE It will be observed from the above table that the higher the metal concentration, the smaller the calculated micropore diameter, which is undesirable for demetalization purposes. Example 5 One-third of the total charge of a reaction column is filled with the catalyst of the present invention extruded into a round cylinder having a diameter of 1/16 inch. The fine structure of the catalyst of the present invention is as follows. That is, 3.0% by weight of molybdenum, 1.2% by weight of cobalt, pore volume of 0.99cc/g, and pore volume of 1000 Å or more.
19%, surface area 196 m ² /g and calculated micropore diameter 161 Å. 1/3 of the total load is covered by U.S. Patent No.
Fill with catalyst No. 4113661. One-third of the total charge is filled with a commercially available irregular quatrefoil shaped desulfurization catalyst from Ketjen. Arabic heavy atmospheric residue oil containing 4.4 weight percent sulfur, 26 ppm nickel, and 89 ppm vanadium is contacted with these catalysts under commercial hydroprocessing conditions. The first catalyst contained in the zone defined herein as the first zone is herein defined as the second zone.
The temperature was maintained at 28° C. higher than the second and third catalysts contained in the zone defined as the zone. The temperature was controlled so that the sulfur content in the product was maintained at 0.6%. When the first catalyst reached 427°C, the first catalyst was held at this temperature and only the second and third catalyst temperatures were increased to maintain the specified concentration of sulfur. The operation was terminated when the temperatures of the second and third catalysts reached 427°C. The effluent of the first zone and the second
Monitor the average product quality for the zone effluent. The results are shown in the table.

[Table] It was found that most of the demetallization occurred on the demetallization catalyst of the present invention. A lifetime of 7 months was demonstrated using this catalyst system. Using the same pressure and space velocity, the lifetime of the interlayer catalyst alone was only 4 months.

Claims (1)

Claims: 1 having a calculated micropore diameter of at least 125 Å, a surface area of at least 100 m ² /g, and a pore volume of at least 0.5 cc/g, and at least 5% of the pore volume having a diameter of 100 Å A catalyst composition for hydrotreating a hydrocarbon feed comprising a shaped alumina support occupied by pores of at least 60% by weight on a metal equivalent basis relative to the total catalyst weight. A catalyst composition characterized in that up to % by weight of a Group B catalytic metal is contained in the support. 2. The catalyst composition of 1 above, which contains 3% by weight or less of a group metal, based on the weight calculated as metal relative to the total catalyst weight. 3. The catalyst composition of 1 above, wherein the alumina is characterized by having an acicular microstructure. 4 1 above, where the crushing strength of the catalyst is 10 kg/cm or more
catalyst composition. 5. To produce a catalyst for hydrotreating hydrocarbon feeds, a peptizer is added to alumina at a temperature of about 20° to 100°C to form a slurry with a pH of 3 to 6, and a nitrogen-containing base and a soluble polymer are added to the alumina. Neutralize the peptized alumina using an aqueous solution of a group B transition metal compound to form a moldable plastic lump, shape the plastic lump, and heat at 100° to 200°C for about 1 to 5 hours. Dry the lumps and heat the dried lumps at 450° to 825°C for about 1 to 6 hours.
A method characterized by baking. 6. The method of 5 above, wherein the alumina is characterized by having an acicular microstructure. 7. The method of 5 above, in which at least a portion of the alumina is previously applied and calcined. 8. The method of 5 above using formic acid as a peptizer. 9. The method of 5 above, in which the deflocculant contains up to 0.06 g mol of group metal per 1 g mol of dry Al ₂ O ₃ . 10 Dry lumps are heated in a steam atmosphere for 1~
3 hours, then 450° for 1/2 to 3 hours in a dry atmosphere
Method 5 above, which involves calcination at 825°C. 11 In preparing a catalyst for hydrotreating a hydrocarbon feed, a peptizer containing a soluble salt of a Group B transition metal compound is added to alumina at a temperature of about 20° to 100°C.
The peptized alumina is made into a slurry with a pH of 3 to 6, and the peptized alumina is neutralized with an aqueous solution of a nitrogen-containing base to form a moldable plastic mass. Dry the lumps at 450° to 825°C for about 1 to 3 hours.
A method characterized by baking. 12. The method of 11 above, wherein the alumina is characterized by having an acicular microstructure. 13. The method of 11 above, wherein at least a portion of the alumina is previously applied and calcined. 14. The method of 11 above using formic acid as a peptizer. 15. The method of 11 above, wherein the deflocculant contains up to 0.06 g mole of Group metal per 1 g mole of dry Al ₂ O ₃ . 16 Dry lumps are heated in a steam atmosphere for 1~
3 hours, then 450° for 1/2 to 3 hours in a dry atmosphere
Method 11 above, in which the method is calcined at 825°C.