CN1275928A - Catalyst, use thereof and preparation process - Google Patents

Abstract

The invention discloses a catalyst, which comprises 0.1-15% by weight of noble metal and 2-40% by weight of manganese and/or rhenium loaded on an acidic carrier, and the noble metal is selected from one or more of platinum, palladium and iridium A kind of metal, said percentage by weight refers to the amount of metal based on the total weight of the carrier. The invention also discloses the use of the catalyst in a process in which a hydrocarbon feedstock comprising aromatic compounds is contacted with the catalyst at high temperature and pressure in the presence of hydrogen. The invention also discloses a preparation method of the above-mentioned catalyst, which includes introducing catalytically active metals into the carrier, followed by drying and calcining.

Description

Catalyst, its application and preparation method

The present invention relates to a catalyst composition and its use in a hydroconversion process wherein a hydrocarbon oil comprising aromatic compounds is contacted with hydrogen in the presence of the catalyst composition. The method of preparation of the catalyst composition is also part of the invention.

Hydroprocessing processes are well known in the prior art, and conventional hydroprocessing catalysts include at least one Group VIII metal component and/or at least one Group VIB metal component supported on a refractory oxide support. The Group VIII metal component can be a non-noble metal such as nickel (Ni) and/or cobalt (Co), or a noble metal such as platinum (Pt) and/or palladium (Pd). Useful Group VIB metal components include molybdenum (Mo) and tungsten (W) based components. The most commonly used refractory oxide support materials are inorganic oxides such as silica, alumina and silica-alumina and aluminosilicates such as modified zeolite Y. Specific examples of conventional hydrotreating catalysts are NiMo/alumina, CoMo/alumina, NiW/silica-alumina, Pt/silica-alumina, PtPd/silica-alumina, Pt/modified Zeolite Y and PtPd/modified zeolite Y.

Hydrotreating catalysts are typically used in processes in which a hydrocarbon oil feedstock is contacted with hydrogen in order to reduce its aromatic, sulfur, and/or nitrogen content. Typically, hydrotreating processes in which the main purpose is to reduce the content of aromatic compounds are referred to as hydroprocessing processes, while processes where the main purpose is to reduce the content of sulfur and/or nitrogen are referred to as hydrodesulfurization processes and hydrodenitrogenation processes, respectively. Current environmental standards require low levels of aromatics, sulfur and nitrogen in oil products, and it is expected that regulations on aromatics, sulfur and nitrogen will become increasingly stringent in the future. Therefore, in the refining of hydrocarbon oil fractions, the capabilities of deep hydrogenation, deep hydrodesulfurization, and deep hydrodenitrogenation will become more and more important.

Effective hydrogenation of monoaromatics is often difficult to achieve with conventional hydrotreating catalysts. On the other hand, conventional specialty aromatics hydrogenation catalysts often have low sulfur and/or nitrogen tolerance, thus, they show poor hydrogenation in the presence of large amounts of sulfur and/or nitrogen containing compounds. Hydrogen activity. For this reason, the conventional approach to reducing the amount of aromatics and sulfur- and nitrogen-containing compounds is a two-step process, the first being a hydrodesulfurization and/or hydrodenitrogenation process (usually after removal of the sulfur hydrogen and ammonia), the second step is the hydrogenation process of the remaining aromatic compounds.

The object of the present invention is to provide a hydrotreating catalyst which exhibits excellent hydrogenation activity of aromatic compounds and simultaneously excellent hydrodesulfurization and/or hydrodenitrogenation activity. Therefore, this means that the catalyst composition is effective in promoting the hydrogenation process of aromatic compounds in the presence of large amounts of sulfur- and nitrogen-containing compounds. A further object of the present invention is to provide a catalyst which exhibits excellent hydrogenation activity for monoaromatic compounds. It should be understood that the use of this catalyst in a hydrotreating process increases the possibility of meeting future regulations for low levels of (mono)aromatics, sulfur and nitrogen.

Therefore, the first aspect of the present invention relates to a catalyst composition loaded on an acidic support, which comprises 0.1-15% by weight of one or more noble metals selected from platinum, palladium, iridium, and 2-40% by weight of For manganese and/or rhenium, said weight percentages refer to the amount of metal based on the total weight of the support.

Manganese and rhenium belong to group VIIB of the periodic table. As is understood by those skilled in the art, the third metal of group VIIB, technetium, is not used due to its instability. On the one hand catalytically active metals such as platinum and/or palladium and/or iridium can be present in elemental form such as oxides, sulfides or mixtures of two or more thereof and on the other hand manganese and/or rhenium can also be present in the form of Elements exist in the form of oxides, sulfides, or mixtures of two or more thereof. As discussed in detail below, suitable preparation methods for preparing the present catalysts include a final step of calcination in air which results in at least a partial conversion of the catalytically active metal to its oxide. Typically, this final calcination step will convert substantially all of the catalytically active metal to its oxide. If the catalyst is subsequently brought into contact with a sulphur-containing feedstock, at least a portion of the oxide is sulphided and thus converted to the corresponding sulphide ("in situ" sulphurization). Very good catalytic performance is observed in this case, and it is therefore considered a preferred technical solution of the present invention that at least a part of the catalytically active metal is present in the catalyst as a sulfide. Accordingly, it is also possible to subject the catalyst to a separate presulfidation treatment prior to contact with the feedstock. The degree of sulfidation of the metal oxides can be controlled by relevant parameters such as the temperature and partial pressure of hydrogen, hydrogen sulfide, water and/or oxygen. The metal oxides can be completely converted into the corresponding sulfides, but an equilibrium should be suitably established between the oxides and sulfides of the catalytically active metal so that the catalytically active metal exists as both the oxide and the sulfide.

As described in detail below, the catalysts of the present invention are suitable for use in a variety of hydroconversion processes. The catalyst has been found to be particularly useful in the hydrotreating of gas oils, thermally and/or catalytically cracked fractions such as light cycle oils and cracked cycle oils, and mixtures of two or more thereof. These oils generally contain relatively large amounts of aromatic, sulfur and nitrogen containing compounds. From the standpoint of environmental regulations, the amount of these compounds usually has to be reduced. Aromatics reduction may also be required in order to meet certain technical quality specifications such as cetane number of motor gasoline, smoke point of jet fuel, and color and stability of lubricating oil fractions. When the catalyst of the present invention is used in the hydrotreating of gas oils, thermally and/or catalytically cracked fractions and mixtures of two or more thereof, the reduction of these compounds, for example required to meet motor gasoline standards, can be achieved in one step . The catalysts of the present invention have been found to be particularly effective in reducing the amount of monoaromatics in the finished product. This is true even in the presence of significant amounts of sulfur- and nitrogen-containing compounds.

The catalyst of the present invention comprises 0.1-15% by weight of platinum and/or palladium and/or iridium catalytically active metals and 2-40% by weight of manganese and/or rhenium. If lower amounts of catalytically active metal are used, the catalyst activity becomes too low to be industrially attractive. On the other hand, if the amount of catalytically active metal is above the indicated upper limit, further increases in catalytic activity will not compensate for the increased cost of the excess amount of metal. This happens especially with platinum and palladium. Good results are obtained with catalysts comprising 3-10% by weight of noble metals, ie platinum and/or palladium and/or iridium, and 2-30% by weight, preferably 5-30% by weight, of manganese and rhenium.

For the noble metal component palladium alone is preferred, while for manganese and rhenium rhenium is the preferred metal. Therefore, very preferred catalysts are catalysts comprising palladium and rhenium as catalytically active metals.

The carrier used to load catalytically active metals is an acidic carrier. Acidic carriers are known in the art. Examples of supports suitable for use in the present invention include those made of aluminosilicates or phosphoaluminosilicates, zeolites, amorphous silica-aluminas, aluminas, fluorinated aluminas, layered silicates, or both or An acid carrier composed of two or more mixtures. It should be understood that the type of acidic support used will depend primarily on the end use of the catalyst. However, for most applications supports comprising zeolites are preferred. Examples of suitable zeolites are phosphosilicates such as SAPO-11, SAPO-31 and SAPO-41 and aluminosilicate zeolites such as Ferrierite, ZSM-5, ZSM-23, SSZ-32, Mordenite, Beta-zeolite and faujasite-type zeolites such as faujasite and synthetic zeolite Y. For example, aluminophosphosilicates are contemplated when using the present catalysts in a lube oil production process that includes a hydroconversion step. However, it is generally preferred to use aluminosilicate zeolites. A particularly preferred aluminosilicate zeolite is zeolite Y, which is often used in a modified, ie dealuminated, form. Especially when the catalyst of the present invention is used as a hydrotreating catalyst for reducing the content of aromatic compounds, sulfur-containing and nitrogen-containing compounds, the use of an acidic support comprising modified zeolite Y is extremely preferred. Particularly useful modified zeolite Y has a unit cell size below 24.6 angstroms, preferably 24.2-24.45 angstroms, more preferably 24.2-24.35 angstroms, and a SiO2/Al2O3 molar ratio of 5 or 10-150, such as 5, 10 or 15 - Modified zeolite Y of 110 or 5, 10, 15, or 30-90. Such carriers are known in the prior art, examples of which are those described in EP-A-0247678; EP-A-0303332 and EP-A-0512652. Also suitable are modified zeolites Y with increased alkali metal (usually sodium) content, such as those described in EP-A-0519573.

In addition to any of the aforementioned carrier materials, the carrier may also include a binder material. The use of binders in catalyst supports is known in the art and suitable binders include inorganic oxides such as silica, alumina, silica-alumina, boria, zirconia and titania , and clay. Of course, the use of silica and/or alumina is preferred in the present invention. Now, the binder content of the carrier can vary between 5 and 95% by weight (based on the total weight of the carrier). In a preferred technical solution, the carrier includes 10-60% by weight of binder. A binder content of 10-40% by weight has been found to be particularly advantageous.

The catalysts of the present invention can be used in various hydroconversion processes. wherein a hydrocarbon feedstock comprising aromatic compounds is contacted with the catalyst at elevated temperature and pressure in the presence of hydrogen. Specific examples of such processes are hydrocracking, lube oil production (hydrocracking/hydroisomerization), and hydrotreating.

Accordingly, the present invention also relates to the use of the above-mentioned catalyst in a process in which a hydrocarbon feedstock comprising aromatic compounds is brought into contact with the catalyst at high temperature and pressure in the presence of hydrogen. Therefore the present catalyst is effective not only for the hydrotreating of aromatic compounds but also for the removal of sulfur and/or nitrogen containing compounds and is particularly suitable for hydrocarbon feedstocks containing sulfur and/or nitrogen containing compounds in addition to aromatic compounds .

The catalyst of the present invention is particularly useful as the first step catalyst in a two-step hydrocracking process due to its excellent hydrotreating properties. The second-step catalyst is a dedicated hydrocracking catalyst.

In lubricating oil production processes, at least one hydroconversion step may be included to remove sulfur and/or nitrogen containing contaminants from the feedstock and to hydrogenate aromatics and/or to degrade linear and slightly side chained hydrocarbons Hydroisomerization to further side chained hydrocarbons and/or hydrocracking of wax molecules (usually long chain paraffin molecules or molecules containing small amounts of this structure) into smaller molecules. The catalyst according to the invention preferably comprises a support comprising amorphous silica-alumina, fluorine-containing alumina or zeolite, and silica and/or alumina as binder. Use of a support comprising modified zeolite Y is preferred if predominantly hydrotreating reactions occur. If cracking and/or hydroisomerization of wax molecules is the primary objective, preferred supports include fluorinated alumina, amorphous silica-alumina, or zeolites such as mordenite, ZSM-5, ZSM-23, ZSM- 32 and SAPO-11. The hydroconversion step in the lubricating oil production process typically involves contacting the lubricating oil feedstock with a suitable catalyst at a temperature of 200-450°C and a pressure of not greater than 200 bar in the presence of hydrogen. Examples of lubricating oil production processes in which the catalyst of the invention may be used are those disclosed in GB-A-1546504 and EP-A-0178710.

The catalysts of the present invention have been found to be particularly suitable for use in hydrotreating processes. Suitable operating conditions for the hydrotreating are a temperature of 200-450°C, preferably 210-350°C or 400°C, and a total pressure of 10-200 bar, preferably 25-100 bar. Examples of suitable hydrotreating processes have been described in European patent applications (published) 0553920 and 0611816. Suitable raw materials for the hydrotreating process are catalytically cracked gasoline, gas oil, light gas oil, thermally and/or catalytically cracked fractions (such as light cycle oil and cracked cycle oil) and mixtures of two or more thereof. Many such feedstocks typically include at least 70% by weight hydrocarbons boiling in the range 150-450°C. When a support is used in such a hydrotreating catalyst, it is preferred that the support includes the amount of binder described above. In the case of hydroprocessing, the preferred acidic material in the support is an aluminosilicate zeolite, most preferably modified zeolite Y. The present catalysts have been found to exhibit excellent hydrotreating activity and are particularly effective for hydrotreating monoaromatics, even in the presence of significant amounts of sulfur or nitrogen containing compounds. The catalyst is also particularly effective for diaromatics and higher aromatics (triaromatics).

The invention also relates to a process for the preparation of the above-mentioned catalysts, which comprises introducing the catalytically active metals into the refractory oxide support by suitable impregnation or ion exchange techniques, followed by drying and calcination and optionally presulfiding. In order to obtain a catalyst with particularly good catalytic activity, the method can be carried out in the following steps:

(a) impregnating the support with one or more solutions containing noble metal compounds selected from platinum, palladium and iridium and one or more solutions containing manganese and/or rhenium compounds, optionally with intermediate drying and/or Calcination; (b) drying and calcining the thus impregnated support at a temperature of 250-650°C.

A preferred method of impregnating the support is the method known as pore volume impregnation which involves treating the support with a volume of impregnating solution substantially equal to the pore volume of the support. In this way, the impregnation solution is fully utilized. The use of this impregnation method according to the invention has been found to be particularly suitable, since the final catalyst exhibits particularly good properties. Impregnation step (a) may be performed using one solution containing all metal components, or impregnation step (a) may be performed in two separate impregnation processes, one impregnating platinum and/or palladium and/or iridium and the other impregnating Manganese and/or rhenium impregnation, intermediate drying and/or calcination steps are also possible.

Metal compounds which can be used in the impregnation solutions for preparing the catalysts of the invention are known in the prior art. Typical manganese compounds are water soluble salts such as manganese sulfate, manganese nitrate and manganese acetate. Typical rhenium compounds are perrhenic acid, ammonium perrhenate, and potassium perrhenate. Typical palladium compounds used in impregnation solutions are tetrachloropalladate (H ₂ PdCl ₄ ), palladium nitrate, palladium(II) chloride and their amine complexes. The use _{of H2PdCl4} is preferred. Typical platinum compounds used in the impregnation solution are hexachloroplatinic acid (H ₂ PtCl ₆ ), optionally in the presence of hydrochloric acid, platinum amine hydroxide and appropriate platinum amine complexes.

During catalyst preparation, it is common practice to calcine the catalyst in air as a final step, thereby converting the metal to its oxide form. In order to convert at least a portion of the metals to their phosphides, the catalyst may be presulfided after the final calcination step and before contact with the feedstock. Suitable pre-vulcanization methods are known in the prior art, for example from European patent applications (published) 0181254, 0329499, 0448435, and 0564317 and international patent applications (published) WO93/02793 and WO94/25157. have technology. Therefore, in the further technical scheme of the present invention, the method for preparing this catalyst also includes steps:

(C) Presulfiding the dried and calcined catalyst.

The pre-vulcanization process can also be carried out by in-situ pre-vulcanization instead of the above-mentioned pre-vulcanization method. This involves contacting the calcined catalyst with a sulfur-containing hydrocarbon feedstock under suitable conditions. The suitable conditions are generally less severe than the envisaged operating conditions.

The catalysts of the invention can be regenerated by methods known in the art. Typical methods for recovering catalytically active metals from spent catalysts include removing the spent catalyst from the reactor, washing the catalyst to remove hydrocarbons, burning off the coke and subsequently recovering the precious metals and/or manganese and/or rhenium.

The present invention is illustrated with the following examples, but the present invention is not limited to these specific technical solutions. Example 1

An acidic catalyst consisting of 80% by weight dealuminated zeolite Y (unit cell size 24.25 Angstroms, silica/alumina molar ratio 80) and 20% by weight alumina binder was used. The carrier sample was impregnated with an aqueous solution of perrhenic acid (HReO ₄ ) so as to achieve 20 wt. % Re0 ₂ (corresponding to 17.1 wt. % Re, said weight percentages being based on the weight of the carrier). The catalyst blank was subsequently dried and calcined at 400° C. for 2 hours, followed by impregnation with aqueous H ₂ PdCl ₄ to a PdO content of 5% by weight (corresponding to 4.3% by weight of Pd). Finally, the finished catalyst was dried and calcined in air at 350°C for 2 hours. This catalyst is hereinafter referred to as PdRe/Y. Example 2

A catalytic bed consisting of 20 cm3 of a mixture of the above-mentioned PdRe/Y and 80 cm3 of silicon carbide particles (SiC; diameter 0.21 mm) was placed in the reactor. The PdRe/Y bed thus obtained was presulfided according to the method disclosed in EP-A-0181254. The method involves impregnation with di-tert-nonyl polysulfide dissolved in n-heptane, followed by drying under nitrogen at atmospheric pressure and 150° C. for 2 hours. The catalyst is then activated by bringing the total reactor pressure to 50 bar by means of hydrogen (gas concentration 500 standard liters/kg). The temperature was raised from room temperature to 250°C over 2 hours, followed by the introduction of feedstock and the temperature was raised from 250°C to 310°C at a rate of 10°C/hour. A temperature of 310°C was maintained for 100 hours.

After completing the activation step, the feedstock is passed through the PdRe/Y bed, and the feedstock has the properties shown in Table I (BP is the boiling point, IBP and FBP are referred to as initial boiling point and final boiling point, respectively). The feedstock was a mixture of 75% by weight straight run gasoline and 25% by weight light cycle oil. The process conditions include: the weight average temperature (WABT) of the PdRe/Y catalytic bed is 350°C, the total pressure is 50 bar, the gas concentration is 500 standard liters/kg, and the weight-hour space velocity (WHSV) is 1.0 kg/liter·hour.

Table I raw material properties S (weight%) 1.37 BP distribution (℃) N(ppmw) 228 IBP10wt%50wt%90wt%FBP 150229287357424 Aromatic compounds (mmol/100g) more than one 77.355.320.4

Determination of sulfur content and nitrogen content (both ppmw), cracking amount (expressed by weight % of material with a boiling point lower than the raw material IBP (i.e. 150°C) formed) and mono-, di- and polyaromatic compound content (in mmol/ 100 g of product indicated).

The results are shown in Table II.

Table II product properties product S(ppmw)N(ppmw) cracking amount (weight% 150℃-) 5197.22 Aromatic compounds (mmol/100g) single two poly 66.06.33.0

It can be seen from Table II that the number of raw materials cracked into low-boiling point materials is minimized, while the PdRe/Y catalyst has excellent hydrodesulfurization and hydronitrogenation activities: the sulfur and nitrogen content are reduced by 96.2% and 96.8%, respectively.

Table II also shows; aromatics conversion is very good. In this respect one can expect that the conversion of poly(tri)aromatics and diaromatics initially increases the content of monoaromatics. Conversion (wt%) can be calculated by assuming a continuous reaction pathway for hydrotreating aromatics, i.e. assuming conversion of polyaromatics to diaromatics, diaromatics to monoaromatics, and monoaromatics Aromatics are converted to cyclic hydrocarbons. This is a valid assumption. This is because it is known that aromatic rings contained in polynuclear structures generally become less kinetically advantaged by hydrotreatment, since the number of aromatic rings in the polynuclear structure is reduced. The monoaromatics found in the product can come from three sources: (i) from unconverted monoaromatics already present in the feed, (ii) from converted diaromatics originally present in the feed. compounds, and (iii) from converted diaromatic compounds derived from converted polyaromatic compounds present in the feedstock. Based on this continuous pathway mechanism, the conversions of polyaromatics, diaromatics, and monoaromatics were found to be as high as 85.3%, 91.3%, and 54.1%, respectively. Example 3

The procedure of Example 2 was repeated except that a PdRe/Y catalyst comprising 5 wt. % PdO (corresponding to 4.3 wt. % Pd) and 5 wt. % ReO ₂ (corresponding to 4.3 wt. The support consisted of 65% by weight modified zeolite Y (unit cell 24.32 Angstroms, silica/alumina molar ratio 9.2) and 35% by weight silica.

The feedstock was a mixture of straight run gasoline and light cycle oil having the properties shown in Table III below. The process conditions used were exactly the same as before except that the feedstock was contacted with the catalyst at a temperature of 360°C.

Table III raw material properties S(ppmw) 3900 BP distribution (℃) N(ppmw) 320 IBP10wt%50wt%90wt%FBP 196287358403435 Aromatic compounds (mmol/100g) Single two more (three +) 54.424.89.814.8

Sulfur and nitrogen content (both ppmw), cracking (expressed as % by weight of material formed boiling below 150°C) and percent conversion of mono, di and polyaromatics were determined.

The results are shown in Table IV.

Table IV product properties product S(ppmw)N(ppmw) cracking amount (weight% 150℃-) 38039.00.9 Aromatic compound conversion rate (%) single two three 50.281.373.1 Example 4

The procedure of Example 3 was repeated except that the process temperature was raised to 380° C. so that the process was carried out in a mild hydrocracking mode (as opposed to the hydrotreating mode in Example 3). All other process conditions remained the same.

Sulfur and nitrogen content (both ppmw), cracking (expressed as % by weight of material formed boiling below 150°C) and percent conversion of mono, di and triaromatics and pour point were determined.

The results are shown in Table V.

Table V product properties product S(ppmw)N(ppmw) cracking amount (weight% 150℃-) 24<118.9 Aromatic compound conversion rate (%) single two three 44.085.185.1 ^* Pour point(℃) -3

^* The pour point of the raw material is 15°C.

Claims (14)

1. A catalyst comprising 0.1-15% by weight of noble metal and 2-40% by weight of manganese and/or rhenium loaded on an acid carrier, the noble metal being selected from one or more metals of platinum, palladium and iridium , said percentage by weight refers to the amount of metal based on the total weight of the carrier. 2. The catalyst of claim 1 comprising 3-10% by weight of noble metal and 2-30% by weight of manganese and/or rhenium. 3. A catalyst as claimed in any one of the preceding claims comprising palladium and rhenium. 4. The catalyst of any one of the preceding claims, wherein the acidic support comprises aluminosilicate zeolites, phosphoaluminosilicates, amorphous silica-aluminas, aluminas, fluorinated aluminas, layered silicates, or a mixture of two or more thereof. 5. The catalyst of claim 4, wherein the acidic support comprises an aluminosilicate zeolite. 6. The catalyst of claim 5, wherein the aluminosilicate zeolite is a modified zeolite Y having a unit cell size of less than 24.60 angstroms, preferably _24.20-24.45 angstroms, and a _SiO2 / _Al2O3 molar ratio of 5-150 , preferably 5-110. 7. The catalyst according to any one of the preceding claims, wherein the acidic support also comprises 5 to 95% by weight of a binder, the binder being preferably silica and/or alumina. 8. Use of a catalyst according to any one of claims 1-7 in a process comprising contacting an aromatic-containing hydrocarbon feedstock with the catalyst at high temperature and pressure in the presence of hydrogen. 9. Use according to claim 8, wherein the hydrocarbon feedstock also includes sulfur- and/or nitrogen-containing compounds. 10. Use according to claim 8 or 9, wherein the process is a hydrotreating process. 11. Use according to claim 8 or 9, wherein the process is a base lubricant production process. 12. Use according to claim 8 or 9, wherein the process is a hydrocracking process. 13. A process for the preparation of a catalyst according to any one of claims 1-7, which comprises introducing the catalytically active metal into the carrier, followed by drying and calcination. 14. The method of claim 13, comprising the step of: (a) impregnating the support with one or more solutions containing compounds of noble metals, and one or more solutions containing compounds of manganese and/or rhenium, the noble metals being selected from on platinum, palladium, iridium, optionally intermediate drying and/or calcination; (b) drying and calcination of the thus impregnated support at a temperature of 250-650° C., followed by optional (c) presulfurization in step (b) The calcined catalyst obtained in .