CN1766047A - Catalytic cracking gasoline selective hydrodesulfurization catalyst and preparation method thereof - Google Patents

Abstract

The invention discloses a selective hydrogenation desulfuration catalyst for catalytically cracking gasoline, wherein the carrying agent is the compound of potassium oxide with two selected from the following: metallic oxide titanium dioxide, aluminium oxide, silica dioxide and magnesium oxide. the active constituents include the metallic combination of two selected from cobalt, molybdenum, nickel and wolfram. The invention also discloses the process for preparing the catalyst.

Description

Catalytic cracking gasoline selective hydrodesulfurization catalyst and preparation method thereof

technical field

The invention relates to a hydrogenation catalyst and hydrogenation desulfurization technology. In particular, it relates to a hydrorefining catalyst with a composite oxide as a carrier and a preparation method thereof. The catalyst of the invention has good hydrodesulfurization activity and performance of inhibiting olefin saturation for catalytic cracking (FCC) gasoline.

technical background

With the increasing requirements for environmental protection, the restrictions on vehicle emissions have become more stringent, and the content control indicators of sulfur, aromatics and other harmful substances in clean fuel specifications have also been continuously improved. FCC gasoline is the main blending component of refined gasoline, and the sulfur compounds in refined oil mainly come from FCC gasoline, so reducing the sulfur content in FCC gasoline is the key to the production of clean gasoline. Hydrogenation is the most effective way to desulfurize gasoline. However, traditional gasoline hydrodesulfurization catalysts also saturate a large amount of olefins during desulfurization, resulting in a significant drop in gasoline octane number and restricting the production of high-grade gasoline.

Therefore, the performance of the catalyst used in the hydrogenation process plays a key role in the technical level of the hydrogenation process. An ideal catalytic cracking gasoline hydrogenation catalyst should have high desulfurization activity and good performance in inhibiting olefin saturation, so as to reduce the loss of octane number caused by olefin saturation in the process of hydrodesulfurization.

At present, most of the gasoline hydrodesulfurization catalysts used at home and abroad are based on alumina or alumina mixed with molecular sieve as the carrier, with cobalt, molybdenum, nickel, and tungsten as the active components. People in the industry have made many attempts in aspects such as performance, adoption of new materials, and preparation methods.

US.Pat.2,853,429 and US.Pat.3,269,938 disclose a kind of catalyzer respectively, and the catalyzer that they use is to take magnesium oxide, silicon oxide and aluminum oxide as carrier, wherein a kind of catalyst BASFK8-11 contains 4wt% CoO and 10wt% %MoO ₃ , the hydrodesulfurization rate of this catalyst is lower than that of traditional catalysts (with γ-Al ₂ O ₃ as the carrier), mainly because the specific surface area of the carrier is small after the introduction of magnesium oxide, and the active components cannot be deposited on the surface of the carrier. It is well dispersed on the surface, which leads to the low desulfurization activity of the catalyst.

US. Pat. 4,140,626 discloses a catalyst, the content of magnesium oxide in the carrier is greater than 70%, and the active components are Mo and Co of VIB and VIII groups. This catalyst can retain some olefins during hydrodesulfurization, thereby avoiding a significant decrease in octane number, but the disadvantage is that magnesium oxide has poor mechanical strength, which limits its industrial application.

US. Pat. 4,132,632 discloses a hydrogenation catalyst based on pure magnesia as a carrier, the loading amount of the active metal component molybdenum is 4-6%, and the loading amount of cobalt is 0.5-2%. The test results show that the hydrogenation desulfurization rate of gasoline by the catalyst can reach 80%, but at the same time, the olefin saturation rate is nearly 40%, and the octane number loses 1.6 units. If the catalyst is used for hydrodesulfurization of heavy oil catalytic cracking gasoline with high olefin content, the olefins will be saturated to a greater extent, and the octane number loss will be greater.

In the petroleum hydrocarbon hydrotreating method proposed in US. Pat. 4,880,524, a hydrogenation catalyst with high activity is used. The catalyst belongs to Ni-Mo/Al ₂ O ₃ type and is prepared by gelation method. The specific surface area of the catalyst is greater than 300m ² /g, and the pore diameter less than 7nm is greater than 70%. Due to the relatively small pore size, the catalyst can only be used in the hydrodesulfurization process of light oil products, and the preparation process of the catalyst is relatively complicated.

Due to the limitation of catalyst activity, when FCC gasoline is hydrodesulfurized, in order to achieve deep desulfurization effect, the temperature and pressure of the reaction are generally raised as much as possible. At this time, the olefin saturation in the desulfurized gasoline will inevitably increase. Affect the quality of gasoline.

To sum up, it is difficult for the currently reported catalysts supported by alumina or magnesia and their modified products to have both good hydrodesulfurization properties and the ability to inhibit olefin saturation when hydrodesulfurizing catalytic cracked gasoline. , and for heavy oil catalytic cracking gasoline with high olefin content, the catalyst does not have a high degree of desulfurization selectivity and good performance in inhibiting olefin saturation, which will inevitably lead to a significant decline in octane number. Even if a catalyst with good desulfurization selectivity has been reported, its preparation method and service life are difficult to meet the needs of large-scale industrialization.

Contents of the invention

The invention provides a new type of hydrogenation catalyst, which can realize catalytic cracking gasoline treatment at lower temperature and pressure, and at the same time of deep desulfurization, the loss of olefin saturation and octane number is small.

The invention also provides a method for preparing the hydrogenation catalyst. Through reasonable process combination, the catalyst has proper particle size and high active component loading rate, and the preparation process is simple and easy to operate and control.

The invention further provides a treatment method for realizing selective hydrodesulfurization of catalytic cracking gasoline by using the above-mentioned catalyst.

The hydrogenation catalyst provided by the present invention is based on the requirement of the catalyst for the hydrodesulfurization selectivity of catalytic cracking gasoline, and the carrier is a compound formed by two kinds selected from titanium dioxide, aluminum oxide, silicon dioxide and magnesium oxide and potassium oxide, and The weight percentage of K ₂ O in the carrier is 0.1-5%, the active component is a combination of two metals in cobalt, molybdenum, nickel and tungsten, the pore volume of the catalyst is 0.2-0.7ml/g, and the specific surface area is 100 ~210 m ² /g.

The inventors have found through a large number of test comparisons that the composite of potassium oxide is used to modify the carrier, and the pore volume and specific surface area of the catalyst after the control are controlled in an appropriate range (not as large as possible), and the resulting catalyst has a higher It has high activity, especially high selective hydrodesulfurization activity, which can effectively suppress olefin saturation while hydrodesulfurization, and ensure that the treated FCC gasoline still has a high octane number effect.

In the catalyst provided by the present invention, the preferred proportions of the metal oxides forming the catalyst carrier are respectively: Al/Mg: 0.08-1, Ti/Si: 0.12-6, Ti/Al: 0.5-2, Ti/Al: Mg: 0.1-4, Si/Mg: 0.2-3.5, for example, Al ₂ O ₃ -MgO-K ₂ O, TiO ₂ -SiO ₂ -K ₂ O, TiO ₂ -Al ₂ O ₃ -K ₂ O can be used and other composite oxides as catalyst supports.

Due to the improvement of the carrier, the loading and dispersibility of the active components on the carrier are increased, which is also conducive to the improvement of the catalytic efficiency. Preferably, the content of the active metal in the catalyst is calculated by oxide content: NiO 1-3%, WO ₃ 10-30%, CoO 1-5%, MoO ₃ 10-18%.

The pore volume of the catalyst of the present invention is 0.2-0.7ml/g, and the specific surface area is 100-210m ² /g, that is, the catalyst of the present invention should have a certain granularity, preferably, the catalyst is a particle of 3-3.6mm.

The preparation method of catalyst of the present invention comprises:

The two kinds of oxides in the titanium dioxide, aluminum oxide, silicon dioxide and magnesium oxide are first made into a complex by using the sol-gel method or the co-precipitation method or the mechanical mixing method, and then made into a compound with potassium oxide by the impregnation method after drying. The complex is baked after drying to become the complex carrier;

The determined active components are carried on the prepared composite carrier by solution impregnation technology, dried and then calcined.

The preparation process of the present invention includes the preparation of the carrier and the preparation of the catalyst. In the preparation of the carrier, a composite body containing two metal oxides is first made, and then the composite carrier modified by potassium oxide is further obtained by impregnation. . The sol-gel method is to dissolve the metal salt in ethanol or isopropanol solution, add deionized water and hydrolysis inhibitor dropwise, and after forming a stable sol, leave it to stand to become a gel; the coprecipitation method The metal salt is dissolved into an aqueous solution, and the alkaline solution is added dropwise to form a precipitate. The drying method can be any feasible method such as carbon dioxide supercritical drying, thermal drying or freeze drying.

The specific process can be:

Sol-gel method: Dissolving a certain amount of the metal salt, such as organic titanium salt, or organic silicon salt, or aluminum salt or a mixture thereof, in an alcohol solution, the alcohol solution used is ethanol or isopropanol. Add deionized water and hydrolysis inhibitor dropwise to the mixed solution. The hydrolysis inhibitor is nitric acid or acetic acid or ammonia water. The purpose is to control the hydrolysis rate of the above salt, so as to obtain a uniformly mixed sol system, and let it stand until it forms a gel;

Co-precipitation method: Dissolve a certain amount of the metal salt, such as inorganic aluminum salt, magnesium salt or titanium salt, in an aqueous solution, and add an alkaline solution to the aqueous solution, preferably a weakly alkaline solution with a pH of 8-10 , to adjust the hydrolysis and precipitation speed of the metal salt, for example, it can be potassium carbonate solution, potassium nitrate solution, sodium carbonate solution, sodium nitrate solution, or ammonia solution, etc. After the precipitation is formed, filter to obtain the precipitation;

Mechanical mixing method: Mix two or three of the pre-determined powders titanium dioxide, silicon dioxide, aluminum oxide, and magnesium oxide according to their respective proportions.

The composite product prepared by the above method is then used to prepare the composite carrier of the present invention by impregnation with a potassium salt solution. The potassium salt is usually an inorganic salt, such as potassium nitrate, potassium sulfate, potassium carbonate, etc., and is supercritically dried with carbon dioxide or During heat drying or freeze drying, the basic requirement is that the dried product should be substantially free of moisture or organic odor. During carbon dioxide supercritical drying, the temperature can be controlled at 40-60°C, the pressure is 8.0-12.0MPa, and the drying time is 1-3 hours; the thermal drying conditions are generally controlled at higher than 100°C (for example, about 110-120°C). The gel or precipitate is thermally dried; freeze-drying can be carried out at -20 to -40°C and 10KPa to dry the gel or precipitate for 2 to 6 hours. The dried product or the mechanically mixed product also needs to be calcined at 400-650° C. in an air atmosphere for 3-8 hours, preferably at a calcining temperature of 500-600° C. and for a calcining time of 3-5 hours.

The drying method can be determined according to the actual situation and operating conditions. Generally, the carbon dioxide supercritical drying method is preferably used when the composite carrier is prepared by the sol-gel method, and the thermal drying method is preferably used when the composite carrier is prepared by the co-precipitation method. The method and device for supercritical carbon dioxide fluid drying are conventional techniques, and the thermal drying process can be known techniques such as hot air drying (for example, using an oven), and will not be repeated here.

The preparation of the catalyst in the present invention adopts an impregnation technique, which may be a simultaneous impregnation method. The composite carrier is impregnated in a mixed solution of an active metal salt, and the impregnation time at room temperature is 4 to 6 hours. For example, when Ni-W is used as an active component , the mixed solution of Ni and W salt solution is used to simultaneously impregnate the composite oxide carrier; the step-by-step impregnation method can also be used to load the two active components on the carrier respectively through two impregnation operations. Preferably, when one of the active components loaded on the carrier is molybdenum, the step-by-step impregnation method is adopted. The composite carrier is first impregnated with a molybdenum-containing solution, dried and calcined, and then impregnated with another active metal solution, and again Drying and calcination, for example, when Co, Mo or Ni, Mo are used as active components, the composite oxide carrier is first impregnated with Mo-containing solution, dried and calcined, then impregnated with Co or Ni-containing solution, dried and calcined again. The impregnating solution of the active component is preferably ammonium metatungstate, nickel nitrate, cobalt nitrate, ammonium molybdate and the like.

After the composite carrier is impregnated with active components, it is preferably dried at 110-120°C for 4-8 hours, and then calcined at 450-650°C for 3-8 hours. The same as the usual method, the calcined product is formed, ground, and sieved to become the final catalyst product. In the present invention, the 3-3.6mm particle product is preferably collected after sieving. At this time, its pore volume and specific surface area all meet the requirements of The need for catalytic hydrogenation reactions.

According to another aspect of the present invention, the application of the above-mentioned catalyst in the desulfurization treatment of FCC gasoline is provided, that is, the hydrogenation catalyst of the present invention is used to carry out hydrodesulfurization treatment of FCC gasoline, which shows good selectivity and is effective in realizing deep desulfurization. At the same time, it can effectively suppress the saturation of olefins and reduce the loss of gasoline octane number.

In the catalyst provided by the present invention, the metal active component must be in the form of sulfide to better exert its catalytic activity, so the catalyst needs to be presulfurized before use, and the specific vulcanization method can use known techniques. Therefore, the hydrodesulfurization method of FCC gasoline provided by the present invention includes using the above-mentioned hydrogenation catalyst to react with FCC gasoline to be treated after sulfidation treatment, and the reaction temperature is 200-350°C, preferably 240-320°C, most preferably 240-280°C, reaction pressure 1-6MPa, preferably 2-4MPa, liquid hourly space velocity 1-10h ^-1 , preferably 1-4h ^-1 .

Among them, the vulcanization treatment is preferably to process the catalyst with the cyclohexane solution of CS ₂ , the concentration of the cyclohexane solution of CS ₂ is 2-6wt%, the vulcanization temperature is 260-360°C, the vulcanization pressure is 2-6MPa, and the vulcanization time is 2 For ~10 hours, the space velocity of the solution feed is 2-10 h ^-1 , and the volume ratio of hydrogen gas to the sulfide solution feed is 300-800.

The treatment method of the present invention mainly selects catalytic cracking gasoline for the selection of reaction raw material oil, which can contain 10-70% alkanes, 20-70% olefins, 10-50% aromatics and a small amount of sulfur-containing and nitrogen-containing compounds. The range of the fraction is 35-205°C, and it can also be arbitrarily cut within the above range, and the sulfide content can be 100-4000 μg/g.

In the choice of reactor, fluidized bed or ebullating bed can be used, but it is better to use fixed bed.

Detailed ways

The technical characteristics of the present invention are further described below through specific examples to help readers better understand the implementation of the present invention and the beneficial effects produced, but it does not constitute any limitation on the implementation scope of the present invention.

Example 1

Preparation of TiO ₂ -SiO ₂ , TiO ₂ -Al ₂ O ₃ Composite Oxide Supports by Sol-Gel Method

Dissolve 34.0g of tetrabutyl titanate and 20.8g of tetraethyl orthosilicate in ethanol solution to form a mixed solution, add 19ml of deionized water and 41.2ml of acetic acid dropwise to the mixed solution, until a stable sol is formed , let it stand until it becomes a gel. Use supercritical carbon dioxide fluid to dry the gel. The drying conditions are temperature 40-60°C, pressure 8.0-12.0MPa, and time is about 1-2 hours (at this time, no water vapor or organic odor can be detected in the tail gas) , and then calcined at 500-600° C. for 3-4 hours to obtain a TiO ₂ -SiO ₂ carrier, wherein the Ti/Si atomic ratio is basically 1:1, which is represented as TS-1.

Weigh 54.4g of tetrabutyl titanate and 8.3g of tetraethyl orthosilicate, or 30g of aluminum nitrate and 40.8g of tetrabutyl titanate, and obtain TiO ₂ -SiO ₂ supports respectively according to the same method, wherein The atomic ratio of Ti/Si is basically 4:1, which is represented as TS-4, and the TiO ₂ -Al ₂ O ₃ composite oxide support, where the atomic ratio of Ti/Al is basically 2:1, is represented as TA-2.

The properties of the obtained composite oxides are shown in Table 1.

Table 1 sample Specific surface area m ² /g Pore volumeml/g Average pore size nm TiO ₂ -SiO ₂ (TS-1)TiO ₂ -SiO ₂ (TS-4)TiO ₂ -Al ₂ O ₃ (TA-2) 431310337 1.390.550.56 12108

Example 2

Preparation of Al ₂ O ₃ -MgO Composite Oxide Support by Co-precipitation

Dissolve 14.856g of aluminum nitrate nonahydrate and 40.618g of magnesium nitrate hexahydrate in the aqueous solution, raise the temperature to 70-80°C (preferably 75°C), add ammonia solution dropwise to the aqueous solution, and wait for the precipitation to form , and a precipitate was obtained by reflux filtration. The precipitate is dried in an oven with a hot air temperature of 110-120°C for about 1-2 hours (at this time, no water vapor or organic odor can be detected in the tail gas). Calcining at 500-600° C. for 3-4 hours to obtain an Al ₂ O ₃ -MgO composite oxide carrier with an Al/Mg atomic ratio of 1:8.

Change the ratio of aluminum nitrate and magnesium nitrate, and prepare supports with different atomic ratios in the same way.

The properties of the obtained composite oxides are shown in Table 2, and the numbers in parentheses after the samples are Al/Mg atomic ratios.

Table 2 Specific surface area, pore volume and pore diameter of Al ₂ O ₃ -MgO composite oxides sample Specific surface area m ² /g Pore volumeml/g Average pore size nm Al ₂ O ₃ -MgO(1:8)Al ₂ O ₃ -MgO(1:10)Al ₂ O ₃ -MgO(1:12) 171.3193.5201.6 0.500.570.62 131210

Example 3

Preparation of TiO ₂ -SiO ₂ -K ₂ O Support

34.0g of tetrabutyl titanate and 20.8g of tetraethyl orthosilicate are dissolved in ethanol solution (isopropanol can also be used) to form a mixed solution, and 19ml of deionized water and 41.2ml of deionized water are added dropwise to the mixed solution Nitric acid, until a stable sol is formed, until it is allowed to stand to form a gel, it is supercritically dried with carbon dioxide (see

Example 1).

Make a solution with 0.3g of potassium nitrate and 12ml of deionized water, mix it evenly with the above-mentioned dry matter by equal volume impregnation method, dry it by heat drying, and roast it at a temperature of 500-600°C and an air atmosphere for 3-4 hours. A TiO ₂ -SiO ₂ -K ₂ O support (wherein the weight ratio of K ₂ O is: 1%) is obtained.

Alternatively, the composite oxides of TiO ₂ -Al ₂ O ₃ and Al ₂ O ₃ -MgO obtained in Example 1 and Example 2 are further prepared in the same way as in this example to prepare TiO ₂ -Al ₂ O ₃ -K ₂ O and Al ₂ O ₃ -MgO-K ₂ O carriers, the weight percentage of K ₂ O is 0.3-1.5%.

Example 4

Preparation of NiW/TiO ₂ -SiO ₂ -K ₂ O Catalyst

Take 4.2ml of ammonium metatungstate solution (0.8823g WO ₃ /ml) and use 7ml of deionized water to make an impregnation solution, and take 1.36g of nickel nitrate hexahydrate and use 6ml of deionized water to make an impregnation solution. The TiO ₂ -SiO ₂ -K ₂ O (expressed as TSK-n, n represents the atomic ratio of Ti to Si) composite oxide obtained in Example 3 was used as a carrier, and at room temperature, 10 g of the carrier was taken, and the above two The impregnating solution is mixed, impregnated for 4-5 hours, dried at 110-120°C for 4-6 hours, and calcined at 450-650°C for 3-4 hours. The 60-80 mesh part after sieving is the catalyst NiW/TiO ₂ -SiO ₂ -K ₂ O (expressed as NiW/TSK-n) of the present invention.

Table 3 shows the basic properties of catalysts prepared using two kinds of TiO ₂ -SiO ₂ -K ₂ O composite oxide supports with Ti/Si atomic ratios of 1 and 4.

Table 3 Basic properties of NiW/TiO ₂ -SiO ₂ -K ₂ O catalysts catalyst Specific surface m ² /g Pore volumeml/g NiO% WO ₃ % NiW/TSK-1NiW/TSK-4 166201 0.350.41 2.712.16 25.7319.75

Example 5

Preparation of CoMo/TiO ₂ -SiO ₂ -K ₂ O Catalyst

Take 1.4g of cobalt nitrate hexahydrate and use 13ml of deionized water to make an impregnation solution, and take 2.23g of ammonium molybdate tetrahydrate and use 13ml of ammonia water to make an impregnation solution. The TiO ₂ -SiO ₂ -K ₂ O composite oxide prepared in Example 3 was used as a carrier, and 10 g of the carrier was taken. At room temperature, first soak the ammonium molybdate ammonia solution for 4 to 6 hours, dry at 110 to 120°C for 4 to 6 hours, and bake at 450 to 650°C for 3 to 4 hours; then soak the cobalt nitrate solution for 4 to 6 hours. Dry at 110-120°C for 4-6 hours, and bake at 450-650°C for 3-4 hours. The 60-80 mesh part after sieving is the catalyst CoMo/TiO ₂ -SiO ₂ -K ₂ O (expressed as CoMo/TSK-n) of the present invention.

Table 4 shows the basic properties of the catalysts prepared with two kinds of TiO ₂ -SiO ₂ -K ₂ O composite oxide supports with Ti/Si atomic ratios of 1 and 4.

The same method as in Example 4 or Example 5 was used to prepare the catalyst using the Al ₂ O ₃ -MgO-K ₂ O prepared in Example 3 as a carrier (expressed as AMK-n).

Table 4 Basic properties of CoMo/TSK catalysts catalyst Specific surface m ² /g Pore volumeml/g CoO% MoO ₂ % CoMo/TSK-1CoMo/TSK-4 126120 0.230.21 1.273.02 12.3814.21

Example 6

Hydrodesulfurization activity of various catalysts

The various catalysts prepared according to above-mentioned embodiment 4, embodiment 5 will carry out the evaluation of reaction performance on hydrogenation micro-reaction device (fixed bed), at first catalyst is carried out sulfidation treatment: sulfidation liquid is the hexanaphthene solution of CS ₂ , The concentration is 2-3%, the vulcanization temperature is 300°C, the vulcanization pressure is 4.0MPa, the vulcanization time is 4 hours, and the feeding space velocity of the vulcanization liquid is 2h ^-1 . The volume ratio of hydrogen to sulfide liquid feed is 600.

The temperature of catalytic cracking gasoline hydrodesulfurization reaction is between 200-300°C, the reaction pressure is between 1-6MPa, and the liquid hourly space velocity is 1-10h ^-1 . Table 5 shows the hydrodesulfurization activity results at a temperature of 280 °C, a pressure of 3 MPa, and a space velocity of 2 h ⁻¹ . The desulfurization rate (HDS), olefin saturation rate (HYD) and selection factor (Z) are used as evaluation indicators. The formula for calculating the selectivity factor is as follows:

Selection factor (Z) = ln(1-HDS%)/ln(1-HYD%)

Table 5 Evaluation results of hydrodesulfurization performance of catalysts catalyst HDS% HYD% Z CoMo/TS-1CoMo/TSK-1NiW/TS-1NiW/TSK-1CoMo/AM-1/10CoMo/AMK-1/10 89.6671.288.0263.192.7486.9 87.3826.187.2831.262.0527.3 1.104.161.032.662.716.38

Example 7

Hydrodesulfurization activity of catalysts at different temperatures

In Example 6, CoMo/TSK-1 and CoMo/AMK-1/10 showed better hydrodesulfurization selectivity, so the reaction performance of CoMo/AMK-1/10 at different temperatures was further investigated, and the reaction pressure was 3MPa , the space velocity is 2h ^-1 , and the temperature range is 220-320°C, preferably 240-300°C, especially 260-280°C. The influence of temperature on the selectivity of hydrodesulfurization is shown in Table 6.

Table 6 Reaction performance of CoMo/AMK-1/10 catalyst at different temperatures Reaction conditions HDS,% HYD,% selectivity 240℃260℃280℃300℃ 31.8269.3286.9 > 94.6 29.2430.5027.343.6 1.113.256.38>5.10

Example 8

Hydrodesulfurization activity of catalysts at different space velocities

Using the CoMo/AMK-1/10 catalyst prepared in Example 5, when the pressure is 3 MPa and the temperature is 180 ° C, the performance of the hydrogenation micro-reactor is investigated. The influence of space velocity on the selectivity of hydrodesulfurization, the space velocity range 1 to 10h ^-1 , the results show that it is preferably 1 to 4h ^-1 , most preferably 2 to 4h ^-1 . Its reactivity is shown in the table below.

Table 7 Reaction performance of CoMo/AMK-1/10 catalyst at different space velocities airspeed HDS,% HYD,% selectivity 1h ^-1 2h ^-1 4h ^-1 90.3986.958.7 55.2727.3023.01 2.916.383.38

Example 9

Hydrodesulfurization activity of catalysts under different pressures

Using the CoMo/AMK-10 catalyst prepared in Example 5, at a temperature of 280°C and at a space velocity of 2h ^-1 , the performance of the hydrogenation microreactor was investigated on the influence of pressure on the selectivity of hydrodesulfurization, and the pressure range was 1 ~6MPa, preferably 2~4MPa, the reaction performance is shown in Table 8.

Table 8 Reaction performance of CoMo/AMK-1/10 catalyst under different pressures pressure HDS, % HYD,% selectivity 2MPa3MPa4MPa 85.886.977.32 25.127.3060.46 6.756.381.60

Example 10

Comparison of gasoline properties before and after selective hydrodesulfurization

Select the CoMo/AMK-1/10 catalyst shown in Example 9 for use, when the reaction temperature is 280°C, the pressure is 2MPa, and the space velocity is 2h ^-1 , the gasoline after selective hydrodesulfurization treatment The comparison between the properties of the product and the properties of the feedstock oil is shown in Table 9.

Table 9 Properties of FCC gasoline after hydrofining raw material product Alkanes (%) Olefins (%) Aromatics (%) RON desulfurization percentage (%) Octane number loss 18.854.127.192.71 46.540.513.090.9485.81.77

In summary, the catalyst of the present invention not only has a good hydrodesulfurization effect on catalytic cracking gasoline, but also can control olefin saturation and octane loss at a lower level, and is a new type of catalytic cracking with comprehensive functions. Gasoline selective hydrodesulfurization catalyst.

Claims (10)

1. A hydrogenation catalyst, the carrier of which is a composite of two kinds selected from titanium dioxide, aluminum oxide, silicon dioxide and magnesium oxide and potassium oxide, and the weight percentage of _K2O in the carrier is 0.1 to 5%, The active component is a combination of two metals in cobalt, molybdenum, nickel and tungsten. The catalyst has a pore volume of 0.2-0.7ml/g and a specific surface area of 100-210m ² /g. 2. The hydrogenation catalyst according to claim 1, wherein the proportions of the metal oxides forming the catalyst support are, in terms of metal atomic ratio, Al/Mg: 0.08-1, Ti/Si: 0.12-6, Ti/Al : 0.5~2, Ti/Mg: 0.1~4; Si/Mg: 0.2~3.5. 3. The hydrogenation catalyst according to claim 1, wherein the contents of the active metals in the catalyst are as follows: NiO 1-3%, WO ₃ 10-30%, CoO 1-5%, MoO ₃ 10-18%. 4. The method for preparing the hydrogenation catalyst according to any one of claims 1 to 3, comprising: The two kinds of oxides in the titanium dioxide, aluminum oxide, silicon dioxide and magnesium oxide are first made into a complex by using the sol-gel method or the co-precipitation method or the mechanical mixing method, and then made into a compound with potassium oxide by the impregnation method after drying. The complex is baked after drying to become the complex carrier; The determined active components are carried on the prepared composite carrier by solution impregnation technology, dried and then calcined. 5. The preparation method according to claim 4, wherein, The sol-gel method is to dissolve the metal salt in ethanol or isopropanol solution, add deionized water and hydrolysis inhibitor dropwise, and after forming a stable sol, let it stand to form a gel; The co-precipitation method is to dissolve the metal salt into an aqueous solution, and drop an alkaline solution to form a precipitate. 6. The preparation method as claimed in claim 4, wherein carbon dioxide supercritical drying, thermal drying or freeze drying can be used to prepare the composite carrier, and the temperature during carbon dioxide supercritical drying is controlled at 40-60°C and the pressure is 8.0-12.0MPa. 7. The preparation method according to claim 4, wherein the solution impregnation technique is a simultaneous impregnation method, in which the composite carrier is impregnated in a mixed solution of active metal salts, and the impregnation time at room temperature is 4-6 hours. 8. The preparation method according to claim 4, wherein one of the active components loaded on the carrier is molybdenum, and the step-by-step impregnation method is adopted. The composite carrier is first impregnated with a solution containing molybdenum, and then impregnated after drying and roasting. Another solution of active metal, dried and fired again. 9. A method for hydrodesulfurization of catalytic cracked gasoline, characterized in that the hydrogenation catalyst described in any one of claims 1 to 3 is used to react with the catalytic cracked gasoline to be treated after sulfidation treatment, and the reaction temperature is 200 to 350°C , the reaction pressure is 1~6MPa, and the liquid hourly space velocity is 1~10h ^-1 . 10. The method according to claim 9, wherein the sulfurization treatment is to treat the catalyst with a cyclohexane solution of CS ₂ , the concentration of the cyclohexane solution of CS ₂ is 2-6 wt%, and the sulfuration temperature is 260-360°C. The pressure is 2-6 MPa, the vulcanization time is 2-10 hours, the solution feed volume space velocity is 2-10 h ^-1 , and the hydrogen-oil volume ratio is 300-800.