CN101255356A - A kind of unsupported catalyst and preparation method thereof - Google Patents

Abstract

A non-supported catalyst for deep hydrofining of middle distillates and a preparation method thereof, specifically, a catalyst particle with nanopores and a relatively high specific surface area is obtained through urea melting reaction. The most prominent technical feature of the present invention is that the urea melting reaction synthesis technology is adopted, the metal is not lost, and the prepared metal composition particles themselves have relatively developed pores and a large specific surface area, which can provide abundant catalytic hydrogenation by itself. The active site, that is for this reason, makes the catalyst of the present invention have much higher catalytic hydrogenation activity than traditional supported catalysts. Simultaneously, the method of the invention is simple, easy to operate, fast in reaction speed, and suitable for industrialized mass production.

Description

A kind of unsupported catalyst and preparation method thereof

technical field

The invention relates to a non-loaded catalyst for ultra-deep hydrotreating of middle distillate oil and its preparation. It belongs to the improvement of the preparation method of hydrogenation catalyst. Specifically, through the melting reaction of urea, a catalyst particle with nanopores and high specific surface area is obtained, and then extruded to obtain a catalyst that is different from the traditional supported catalyst. The so-called unsupported catalysts, compared with traditional supported catalysts, unsupported catalysts have higher catalytic activity.

Background technique

In recent years, the trend of poor quality of crude oil has become increasingly obvious worldwide, and the content of sulfur, nitrogen and aromatics in petroleum products has been increasing day by day, and the contradiction between increasingly stringent environmental protection requirements and this reality has become more and more acute. More than one-third of my country's petroleum products, especially diesel products, are produced by catalytic cracking technology. With the widespread application of heavy oil catalytic cracking technology, catalytic cracking raw materials gradually become heavier and worse, making the properties of catalytic cracking diesel oil increasingly worse. The content of sulfur, nitrogen and aromatics in diesel is increasing day by day, and the cetane number is significantly reduced. At present, in order to alleviate air pollution, countries around the world have put forward stricter requirements on the quality indicators of vehicle fuels. The content of sulfur, nitrogen and aromatics in vehicle diesel indicators has been greatly reduced, and the cetane number requirements have been significantly increased. At present, Europe and the United States limit the standard sulfur content of diesel to 150-350ug/g, and it will be limited to 50ug/g by 2005. Countries such as the European Union, the United States, and Japan have recently vigorously advocated the implementation of the ultra-low diesel standard (ULSD) in the near future. It is required that the sulfur content in vehicle diesel is limited to 10-15ppm.

As we all know, hydrogenation process is one of the most effective means of improving oil quality, and hydrogenation catalyst is the most important and key technology in hydrogenation process. Therefore, many petroleum and petrochemical companies at home and abroad are currently committed to improving the existing Improvement of hydrogen catalysts, in order to continuously develop better performance of hydroprocessing catalysts. Combined with the current technical situation at home and abroad, low-quality diesel oil (for example: high-sulfur naphthenic straight-run diesel oil, coking diesel oil, catalytic cracking diesel oil or mixed diesel oil of the above raw materials) can only be processed through deep hydrotreating (desulfurization, denitrification, olefins, aromatics, etc.) Saturation) can be used as a blending component of diesel for vehicles. Therefore, a hydrotreating catalyst especially suitable for ultra-deep hydrotreating of low-quality diesel is one of the types of catalysts that are urgently needed in the petroleum refining industry.

Traditional hydrofining catalysts are generally composed of metals or metal oxides with hydrogenation function and supports. The commonly used metal components are VIB group and VIII metals, such as cobalt, molybdenum, nickel, tungsten, etc. These catalysts are generally impregnated The metal active component is loaded on the carrier by the method, and its catalytic activity is relatively mild due to the limitation of the metal loading (generally, the loading of the active metal oxide is less than 30%). Of course, the activity and selectivity of the catalyst can be improved by optimizing the preparation process and changing the properties of the carrier, making it more suitable for deep hydrotreating of inferior diesel fractions. This type of technology is such as: US4,188,281 introduces a kind of hydrotreating catalyst with VIB, VIIB, VIII group metals as active components, with faujasite (adding a small amount of alumina as a binder) as a carrier, the catalyst It can be used in the hydrotreating process of heavy oil. The tail oil after hydrotreating is used as the raw material for steam cracking to produce ethylene, and the yield of ethylene is greatly improved; in US3,779,903, the alumina sol is dried and roasted to obtain pores A carrier with a volume of 0.15-0.45ml/g, impregnated with nickel and tungsten, dried and roasted to obtain a catalyst containing 10-18% by weight of nickel oxide, 25-40% by weight of tungsten oxide and 1-9% by weight of fluorine; US4 , 330,395 disclosed a kind of tungsten compound and aluminum compound as raw material, by evaporating to dryness, roasting, impregnating with nickel compound, then sulfurizing and fluorinating with sulfur compound and fluorine compound to prepare a middle distillate hydrotreating catalyst ; CN85,104,438B adopts the high-purity gibbsite prepared by the hydrolysis method of alkoxy aluminum or alkyl aluminum as the precursor of the catalyst carrier, and prepares a kind of nickel oxide containing 1-5 weight %, tungsten oxide 12-35 % by weight, fluorine 1-9 weight % hydroprocessing catalyst; CN1,105,053 discloses a catalyst suitable for heavy distillate oil hydroprocessing, the catalyst is composed of nickel oxide 1-5 weight %, tungsten oxide 15 ～38% by weight, 1～9% by weight of fluorine, its carrier is a kind of modified alumina obtained by treating with air and water vapor at high temperature; CN1,169,336A discloses a catalyst for distillate hydrotreating, the The composition of the catalyst is 1-5% by weight of nickel oxide, 15-38% by weight of tungsten oxide, 1-9% by weight of fluorine, and the rest is alumina. The alumina carrier is composed of one or more small-pore alumina and a or a variety of macroporous alumina compounded according to the weight ratio of 75:25 to 50:50, wherein the pore volume of small-pore alumina micropores with a diameter of less than 8nm accounts for more than 95% of the total pore volume. Alumina whose micropore diameter is 6-60nm and whose pore volume accounts for more than 70% of the total pore volume.

It can be seen that although the above-mentioned catalysts have modified the properties of the carrier, their hydrogenation activity still cannot meet the requirements of ultra-deep hydrotreating of middle distillates, especially low-quality diesel oil. In order to improve the activity of hydrogenation catalysts, some new catalyst preparation technologies have been used in production in recent years. For example, US 6,652,738 and US 6,534,437 disclose a method for preparing bulk catalysts, using a hydrothermal synthesis method to obtain a mixed metal combination For the preparation of hydrogenation catalysts, US 4,596,785 discloses a method for preparing hydrogenation catalysts using metal sulfide co-precipitation. Although the catalysts prepared by these methods can improve hydrogenation activity, the disadvantages of these methods are mainly: (1) hydrothermal synthesis or co-precipitation will cause part of the metal loss, and the metal recovery rate is low; (2) the obtained The specific surface area of the pore structure of the mixed metal composition is small, and the metal utilization rate of the catalyst is not high, resulting in an increase in the cost of the catalyst.

Contents of the invention

The purpose of the present invention is to avoid the shortcomings of the prior art and propose a non-supported catalyst for ultra-deep hydrotreating of middle distillate oil. This method can overcome the shortcomings of hydrothermal reaction and co-precipitation reaction method, and improve metal recovery. rate, increasing the specific surface area of the catalyst, which can greatly improve the hydrogenation activity of the catalyst. The catalyst with high hydrogenation activity, its active component is composed of one or two of Co, Ni and one or two metal components of Mo, W, and its active metal oxide content is 30-100wt %. The concrete preparation steps of catalyst described in the present invention are as follows:

(1) Precursors of metal components

In the catalyst with high hydrogenation activity provided by the present invention, its Group VIII metals are generally Fe, Co, Ni and other metals, preferably Ni and Co, and its metal oxide content is generally 10-90%, preferably 20-80%. , the VIB group metals are generally Mo, W, Cr and other metals, preferably Mo and W, and the metal oxide content is generally 1-90%, preferably 20-80%. The metal precursors used can be one or two metals of group VIII, plus one or two metals of group VIB, such as Co-Mo, Ni-Mo, Ni-W, Co-Ni-W, Ni-Mo -W, Co-Mo-W, Co-Mo-Ni-W, etc. According to the preparation method of the catalyst provided by the present invention, the active metal precursors include active metal salts, oxides and acids, etc., metal salts such as Co, Mo, Ni, W carbonate, nitric acid Salt, phosphate, citrate, tungstate, molybdate, etc.

(2) Urea melting reaction

The preparation method of the catalyst with high hydrogenation activity provided by the present invention is to mix the above-mentioned metal component precursor with urea and react in the molten state of urea, remove excess urea, and obtain a catalyst with nanopores and high specificity. For catalyst particles with a surface area, the mass ratio of the amount of urea used to the metal substance is 1 to 5/1, preferably 2 to 3/1. The mixed reaction method can be commonly used methods such as grinding, stirring, and ultrasonic dispersion. , the reaction temperature is generally 100-200°C, preferably 120-150°C, and the reaction time is 2-10 hours, preferably 4-6 hours. The said catalyst particle itself has nano-pores and relatively high specific surface area, its pore diameter is 3-10nm, its specific surface area by BET method is 100-450m ² /g, generally 150-350m ² /g.

The most prominent technical feature of the present invention is that due to the adoption of the urea melting reaction synthesis technology, the reaction speed is fast, so that the prepared metal compound particles themselves have relatively developed pores and a large specific surface area, which can provide abundant catalytic and catalytic properties. hydrogen active site. It is for this reason that the catalyst of the present invention has much higher catalytic hydrogenation activity than traditional supported catalysts.

(3) Catalyst molding

According to the preparation method of the catalyst provided by the present invention, the catalyst can be in the form of powder, and can also be molded, and a certain amount of binder can be added during the molding process, and its addition is 0-50%, preferably 10-30%. The binder can be selected from commonly used types in industry, such as silica sol, aluminum sol, and the like. Said molding method wherein includes methods such as tablet pressing, into ball or extruding, preferably adopts the method for extruding molding.

(4) Activation of the catalyst

According to the preparation method of the catalyst provided by the present invention, the said catalyst can be processed by roasting, the roasting temperature is 200-500°C, and the time is 2-8 hours; the best roasting temperature is 250-400°C, and the time is 4-8 hours. 6 hours.

According to the preparation method of the catalyst provided by the present invention, the catalyst must be presulfurized, the vulcanization temperature is 200-450°C, preferably 300-400°C, and the vulcanization time is 8-48 hours, preferably 10-48 hours. After 25 hours, the volume ratio of hydrogen to oil is 100-800, preferably 300-500.

The catalyst provided by the present invention can be used for ultra-deep hydrotreating of oil products including light, medium and heavy distillates, and other suitable hydrotreating occasions, such as: hydrodesulfurization, hydrodenitrogenation, hydrogenation Hydrodemetallization, hydrogenation saturation of olefins and aromatics, etc., the applicable process conditions are conventional hydrogenation process conditions. The catalyst can be made into different types of solid particles according to needs, for example, it can be used in hydrogenation processes such as fixed bed, fluidized bed and suspended bed.

Detailed ways

The technical characteristics of the present invention will be described in detail below in conjunction with the embodiments.

Example 1

This example illustrates the preparation method of the catalyst of the present invention.

Weigh 14.2 grams of molybdenum trioxide (0.1 moles of Mo), 25.0 grams of tungstic acid (0.1 moles of W), 41.5 grams of basic nickel carbonate (0.3 moles of Ni), and add 161.4 grams of urea into a three-necked flask, and add a small amount of Water to make it evenly dispersed, put it in an oil bath at 130°C and stir for 4 hours, pour the reactant into a tray to cool while it is hot, crush the cooled product with a pulverizer, and dry it in an oven at 150°C. Excess urea breaks down. Weigh pseudo-boehmite with 30% weight of solid powder and add 10% dilute nitric acid solution to make aluminum sol, add the solid powder to the aluminum sol, and make a paste, knead and extrude to make a diameter of 1.6mm The strips were dried under an infrared lamp for 5 hours, then dried in an oven at 110°C for 10 hours, and calcined in a muffle furnace at 400°C for 5 hours to obtain unsupported catalyst F1. The BET surface area of the catalyst is 232.0m ² /g, the pore volume is 0.35cm ³ /g, and the average pore diameter is 5.8nm.

Example 2

This example illustrates the preparation method of the catalyst of the present invention.

Get the ammonium molybdate (0.1 mole Mo) of 17.6 grams, the ammonium metatungstate (0.1 mole W) of 26.4 grams, the basic nickel carbonate (0.3 mole Ni) of 41.5 grams, 171.0 grams of urea join in the there-necked flask, and add A small amount of water to disperse it evenly, put it in an oil bath at 130°C and stir for 4 hours, pour the reactant into a tray to cool while it is hot, pulverize the cooled product with a pulverizer, and dry it in an oven at 150°C. Decompose excess urea. Weigh the pseudo-boehmite with 30% weight of solid powder and add dilute nitric acid solution with a concentration of 10wt% to make aluminum sol, add the solid powder to the aluminum sol, and make a paste, knead and extrude to make a diameter The 1.6mm strips were dried under an infrared lamp for 5 hours, dried in an oven at 110°C for 10 hours, and calcined in a muffle furnace at 400°C for 5 hours to obtain catalyst F2. The BET surface area of the catalyst is 240.6m ² /g, the pore volume is 0.31cm ³ /g, and the average pore diameter is 5.5nm.

Example 3

This example illustrates the preparation method of the catalyst of the present invention.

Weigh 14.2 grams of molybdenum trioxide (0.1 moles of Mo), 25.0 grams of tungstic acid (0.1 moles of W), 27.6 grams of basic nickel carbonate (0.2 moles of Ni), and 133.6 grams of urea into a three-necked flask, and add a small amount of Water to make it evenly dispersed, put it in an oil bath at 130°C and stir for 4 hours, pour the reactant into a tray to cool while it is hot, crush the cooled product with a pulverizer, and dry it in an oven at 150°C. Excess urea breaks down. Weigh the pseudo-boehmite with 30% weight of solid powder and add dilute nitric acid solution with a concentration of 10wt% to make aluminum sol, add the solid powder to the aluminum sol, and make a paste, knead and extrude to make a diameter The 1.6mm strips were dried under an infrared lamp for 5 hours, dried in an oven at 110°C for 10 hours, and calcined in a muffle furnace at 400°C for 5 hours to obtain catalyst F3. The BET surface area of the catalyst is 200.5m ² /g, the pore volume is 0.30cm ³ /g, and the average pore diameter is 6.8nm.

Example 4

This example illustrates the preparation of a comparative catalyst.

Take by weighing 14.2 grams of molybdenum trioxide (0.1 moles of Mo), 25.0 grams of tungstic acid (0.1 moles of W), 27.6 grams of basic nickel carbonate powder (0.2 moles of Ni), add 20 grams of pseudo-boehmite and mix uniformly, Then add dilute nitric acid solution with a concentration of 10wt% to make a paste, knead and extrude to make strips with a diameter of 1.6mm, dry them under an infrared lamp for 5 hours, and then dry them in an oven at 110°C for 10 hours. The comparative catalyst was prepared by calcining at 400°C for 5h in a muffle furnace.

Example 5

The present embodiment illustrates the evaluation method of catalyst of the present invention

Catalyst activity evaluation was carried out in a 10mL high-pressure microreactor. The raw material composition of the model compound is: 10% naphthalene, 2% dibenzothiophene (DBT) (about 3630 ppm sulfur), 2% quinoline (about 2170 ppm nitrogen), 86% toluene. The raw material is pumped in with a plunger pump, and the hydrogenation product is separated from liquid and gas by a high-pressure separator (cold high fraction) and a low-pressure separator, and the liquid product flows into the sample receiving tank. At 120°C, start pumping cyclohexane containing CS ₂ (3wt%) for pre-sulfurization, raise the temperature to 360°C, vulcanize for 10 hours, and the liquid hourly space velocity is 2.0h ^-1 . Then cool down to the reaction temperature, start to feed the raw material (model compound), take a sample after the reaction is stable for 5 hours, and analyze it with a gas chromatograph (Varian3800 capillary chromatographic column, FID detector). Reaction conditions: 340°C, liquid hourly space velocity: 2.0h ^-1 , hydrogen-oil ratio: 300/1, reaction pressure: 2.0MPa. The reaction evaluation results of several catalysts are shown in Table 1.

The results in Table 1 show that the hydrodesulfurization, hydrodenitrogenation and aromatics hydrogenation activities of the hydrogenation catalyst prepared by the present invention are significantly higher than those of the comparative catalyst prepared by the traditional kneading method.

Table 1 Catalyst activity evaluation result of the present invention

Catalyst HDS,% HDN,% HDAr, % F1 99.0 87.9 55.9 F2 100.0 86.0 52.1 F3 99.6 88.2 54.1 Comparing Catalysts 95.8 63.5 39.1

Invention effect

Compared with the prior art, the most prominent technical feature of the present invention is that the synthesis technology of urea melting reaction is adopted, the metal is not lost, and the prepared metal composition particles themselves have more developed channels and a larger specific surface area, which themselves are Abundant catalytic hydrogenation active sites can be provided, which is why the catalyst of the present invention has much higher catalytic hydrogenation activity than traditional supported catalysts. Simultaneously, the method of the invention is simple, easy to operate, fast in reaction speed, and suitable for industrialized mass production. The catalyst provided by the present invention can be used for ultra-deep hydrotreating of oil products including light, medium and heavy distillates, and other suitable hydrotreating occasions, such as: hydrodesulfurization, hydrodenitrogenation, hydrogenation Hydrodemetallization, hydrogenation saturation of olefins and aromatics, etc., the applicable process conditions are conventional hydrogenation process conditions. The catalyst can be made into different types of solid particles according to needs, for example, it can be used in hydrogenation processes such as fixed bed, fluidized bed and suspended bed.

Claims (3)

1. the preparation method of a unsupported catalyst, this catalyzer is several metal component precursor and urea to be mixed to be incorporated in react resultant a kind of catalyst particles that self has nano pore and high specific surface area under the molten state.It is characterized in that its metal component can be that one or both metal ingredients among one or both and Mo, the W among Co, the Ni constitute, these metal components can use its metal oxide, salt, metal precursor such as acid; It reacts under molten state, is meant that in temperature of reaction be 100～200 ℃, and the reaction times is to react in 2～10 hours, and its reactant is dispersed in molten state urea the inside; With the metal oxide timing, the mass ratio of the amount of its urea and the total material of metal is 1～5/1; Resulting catalyzer is measured through the BET method, himself has the catalyst particles of nano pore and high specific surface area, and its channel diameter is 3～10nm, and specific surface area is 100～450m ²/ g,

2. the preparation method of a kind of unsupported catalyst according to claim 1 is characterized in that described catalyzer can be a powder type, also can carry out forming processes; Its moulding process is the binding agent of adding 10～30%, and binding agent can be silicon sol, aluminium colloidal sol etc., and its forming method comprises methods such as compressing tablet, balling-up or extrusion.

3. the preparation method of a kind of unsupported catalyst according to claim 1 is characterized in that catalyzer can carry out calcination process, and its maturing temperature is that 200～500 ℃, time are 2～8 hours; When catalyzer is used for hydrogenation, can also carry out prevulcanized and handle, its curing temperature is 200～450 ℃, and curing time is 8～48 hours, and hydrogen to oil volume ratio is 100～500.