CN108970628B

CN108970628B - Preparation method of ebullated bed hydrotreating catalyst

Info

Publication number: CN108970628B
Application number: CN201810893969.4A
Authority: CN
Inventors: 查春鸿; 贾建文; 赵婷
Original assignee: Beijing Zhongzhi Innovation Science & Technology Development Co ltd
Current assignee: Beijing Zhongzhi Innovation Science & Technology Development Co ltd
Priority date: 2018-08-08
Filing date: 2018-08-08
Publication date: 2023-08-29
Anticipated expiration: 2038-08-08
Also published as: CN108970628A

Abstract

The invention discloses a preparation method of a boiling bed hydrotreating catalyst, which comprises the following steps: (1) Kneading pseudo-boehmite and basic ammonium aluminum carbonate for adsorbing a carbon precursor solution to form a formed product, and drying the formed product; (2) Spraying and dipping the material obtained in the step (1) by using a solution containing a carbon precursor, and drying and roasting the sprayed and dipped material to obtain an alumina carrier; (3) Impregnating the alumina carrier obtained in the step (2) with an impregnating solution containing hydrogenation active components, and drying and roasting the impregnated alumina carrier to obtain the ebullated bed hydrotreating catalyst; the catalyst prepared by the method has higher strength and wear resistance, and is particularly suitable for the heavy oil ebullated bed hydrotreatment process.

Description

Preparation method of ebullated bed hydrotreating catalyst

Technical Field

The invention relates to the field of preparation of hydrotreating catalysts, in particular to a preparation method of a hydrotreating catalyst suitable for a heavy oil ebullated bed.

Background

In recent years, crude oil is increasingly heavier, and the demand of the market for middle distillate products is continuously increasing, and the demand of heavy oil fuel is gradually decreasing, so that the conversion of low-value heavy oil into light oil with higher added value is the target pursued by various large refineries. The catalytic hydrogenation process commonly used for heavy oil products is mainly a fixed bed hydrogenation process. The fixed bed reactor has the characteristics of stable operation and easy control, but the fixed bed process for hydrotreating heavy oil products has the following problems: because heavy oil is heavier and contains more mechanical impurities, the catalytic reaction conditions are more severe; the high-nitrogen raw material can accelerate the deactivation of the catalyst, the service cycle of the catalyst is short, and the product property cannot be ensured; the catalyst bed pressure drops high.

In order to meet the product specifications, the fixed bed reactor system needs to be of a more complex design, which increases the investment cost. The boiling bed hydrogenation process has the characteristics of strong adaptability to raw materials, flexible processing scheme and the like, and is one of effective means for deep processing of heavy oil. In the fluidized bed hydrotreating process, raw oil and hydrogen flow upwards through a catalyst bed layer, the bed layer is boiled, catalyst particles are in an irregular motion state in a reactor, and the catalyst particles have more collision and friction opportunities, so that the catalyst is easy to abrade or destroy, and therefore, the catalyst is required to have higher hydrogenation activity and better wear resistance.

USP5308472 discloses a dealuminated Y molecular sieve-containing catalyst useful in ebullated-bed mild hydrocracking reactions. The catalyst can be used for hydrodemetallization, hydrodesulphurisation and hydrocracking of heavy raw materials. The catalyst contains 1-6wt% of VIII metal oxide, 12-25wt% of molybdenum oxide and 1-5wt% of phosphorus oxide compound. The catalyst has higher cracking activity, but the strength and the wear resistance of the catalyst need to be further improved.

CN200710010377.5 discloses ebullated bed hydrotreating catalysts and methods of making the same. The boiling bed hydrotreating catalyst of the invention is spherical with the diameter of 0.1-1.8mm, contains proper auxiliary agent and hydrogenation active metal component, and has reasonable pore distribution. The preparation method of the catalyst adopts a spherical carrier impregnation method, the spherical carrier preparation process is to prepare the catalyst carrier raw material with proper humidity into particles with proper size, then spheroidize the particles, and heat the spheroids to prepare the spherical catalyst carrier. The ebullated bed hydrotreating catalyst in the prior art has the advantages of uniform particles and excellent performance, but the attrition resistance of the catalyst needs to be further improved.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a preparation method of a boiling bed hydrotreating catalyst. The catalyst prepared by the method has higher strength and wear resistance, and is particularly suitable for the heavy oil ebullated bed hydrotreatment process.

The invention relates to a preparation method of a boiling bed hydrotreating catalyst, which comprises the following steps:

kneading pseudo-boehmite and basic ammonium aluminum carbonate for adsorbing a carbon precursor solution to form a formed product, and drying the formed product;

spraying and dipping the material obtained in the step (1) by using a solution containing a carbon precursor, and drying and roasting the sprayed and dipped material to obtain an alumina carrier;

and (3) impregnating the alumina carrier obtained in the step (2) with an impregnating solution containing hydrogenation active components, and drying and roasting the impregnated alumina carrier to obtain the ebullated bed hydrotreating catalyst.

In the method of the invention, the basic aluminum ammonium carbonate in the step (1) can be prepared in the market or the prior art, preferably is basic aluminum ammonium carbonate with a rod-shaped structure, the length of the rod-shaped basic aluminum ammonium carbonate is 1-5 mu m, the diameter of the rod-shaped basic aluminum ammonium carbonate is 100-300nm, and the adding amount of the basic aluminum ammonium carbonate is 15-35 wt% of the weight of the pseudo-boehmite in the step (1).

In the method of the invention, the carbon precursor in the step (1) is a polyhydric alcohol and/or a saccharide substance, and the polyhydric alcohol is one or more of xylitol, sorbitol, mannitol and arabitol; the saccharide is one or more of glucose, ribose, fructose, triose, tetrose, pentose, hexose, and non-saccharide. The carbon precursor is adsorbed into basic aluminum ammonium carbonate in the form of a solution, the mass concentration of the carbon precursor solution is 20-40 wt%, the solution is used for completely immersing the basic aluminum ammonium carbonate, and the immersing time is 1-3 hours.

In the method, the kneading molding in the step (1) is carried out by adopting a conventional method in the field, the pseudo-boehmite is prepared by any method, and conventional molding aids such as a peptizing agent, an extrusion aid and the like can be added according to the need in the molding process. The peptizing agent is one or more of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, oxalic acid and the like; the addition amount of the peptizing agent is 0.5-3 wt% of the weight of the alumina carrier. The extrusion aid is sesbania powder, and the addition amount of the extrusion aid is 0.1-0.5 wt% of the weight of the alumina carrier. The drying temperature is 100-160 ℃, and the drying time is 6-10 hours.

In the method of the invention, the carbon precursor solution in the step (2) is an aqueous solution of polyalcohol and/or saccharide, and the polyalcohol is one or more of xylitol, sorbitol, mannitol and arabitol; the saccharide is one or more of glucose, ribose, fructose, triose, tetrose, pentose, hexose, and non-saccharide. The mass concentration of the carbon precursor solution is 10-20wt%, and the dosage of the solution is 10-20wt% of the saturated absorption capacity of the molding material.

In the method, the drying temperature in the step (2) is 100-160 ℃, and the drying time is 6-10 hours.

In the method of the invention, the roasting in the step (2) is two-stage roasting, firstly, the roasting is carried out under an inert atmosphere, the roasting temperature is 600-750 ℃, the roasting time is 4-8 hours, and the inert atmosphere is nitrogen, argon and other gases, preferably nitrogen. Then roasting in oxygen atmosphere at 600-750 deg.c for 4-8 hr.

In the method of the invention, the hydrogenation active component impregnating solution in the step (3) is prepared according to the composition calculation of the target catalyst. In the hydrogenation active component impregnating solution, the content of the metal of the VIB group is 7-15g/100ml calculated by oxide, the content of the metal of the VIII group is 0.8-3g/100ml calculated by oxide, and the impregnation time is 1-5 hours in modes of over-volume impregnation, equal-volume impregnation or spray impregnation and the like.

In the method of the invention, the drying and roasting conditions in the step (3) are carried out according to the conventional method in the field, and the drying conditions are that the drying is carried out for 6-10 hours at 80-120 ℃; the roasting condition is that roasting is carried out for 3-6 hours at 400-600 ℃.

The invention has made remarkable progress.

The technology of the invention firstly uses carbon-containing precursor solution to impregnate rod-shaped basic ammonium aluminum carbonate, the impregnated basic ammonium aluminum carbonate and pseudo-boehmite are kneaded and molded, and then dried, the dried material is subjected to unsaturated spray impregnation of the carbon-containing precursor solution, and the alumina carrier is prepared by drying, roasting in nitrogen atmosphere and roasting in oxygen atmosphere, and finally the catalyst is prepared by impregnating active components.

In the forming process, the rodlike basic ammonium aluminum carbonate is added, so that rodlike structures are stacked in a staggered manner, and a larger pore canal which is beneficial to mass transfer and diffusion of heavy residual oil macromolecules is formed. The pore canal is formed by staggered stacking of micron rod-shaped basic aluminum ammonium carbonate, so that the carrier has higher mechanical strength while the macropores are ensured. When the formed material is roasted in inert atmosphere, the carbon precursor forms carbon material and distributes on the surface of the carrier and the rod-shaped alumina, and after oxygen is introduced, the carbon material burns and releases heat rapidly, so that the temperature of the local part of the alumina carrier (the surface of the carrier and the position containing the rod-shaped alumina) is increased, the alumina crystal grains are enlarged or the crystal phase is changed due to the increase of the temperature, the macropore content is improved, and meanwhile, the mechanical strength and the wear resistance of the carrier are improved. In addition, the chemical property of the surface of the carrier is modulated due to the improvement of the local roasting temperature, so that the activity of the catalyst is improved.

Brief description of the drawings

FIG. 1 is a scanning electron microscope photograph of basic aluminum ammonium carbonate prepared according to the present invention.

Detailed Description

The following examples are provided to further illustrate the technical aspects of the present invention, but are not limited thereto. In the invention, the weight percent is the mass fraction.

The pore structure of the catalyst of the examples and the comparative examples is characterized by using N2 physical adsorption-desorption, and the specific operation is as follows: and (3) characterizing the structure of the sample hole by adopting an ASAP-2420 type N2 physical absorption-desorption instrument. And (3) taking a small amount of samples, carrying out vacuum treatment for 3-4 hours at 300 ℃, and finally, placing the products under the condition of low temperature (-200 ℃) of liquid nitrogen for nitrogen adsorption-desorption test. Wherein the surface area is obtained according to the BET equation, and the pore size distribution and pore volume are obtained according to the BJH model.

Preparation example 1: and (3) preparing basic aluminum ammonium carbonate. Basic aluminum ammonium carbonate used in the technique of the invention is as follows: comparative study of the preparation of alumina with aqueous ammonia and ammonium carbonate as precipitants [ J ]. Inorganic chemistry report, 2004, 20 (6), 688-692, scanning electron microscope photograph of the prepared basic ammonium aluminum carbonate is shown in FIG. 1.

Example 1

50g of basic aluminum ammonium carbonate is weighed, xylitol solution with the mass concentration of 20wt% is used for impregnating the materials for 2 hours, the impregnated materials are filtered and then are mixed with 200g of pseudo-boehmite dry gel powder (the dry basis content of alumina is 70wt% produced by Winzhou refined alumina Co., ltd.), 0.2g of sesbania powder is uniformly mixed, a proper amount of aqueous solution with 3g of acetic acid dissolved in the mixture is added, the mixture is extruded and shaped, and the shaped material is dried at 120 ℃ for 8 hours.

100 g of dried strip material is weighed and placed in a spray-dipping roller pot, 10mL of sorbitol aqueous solution with mass concentration of 15% is used for spraying and dipping the carrier, the dipped carrier is dried at 120 ℃ for 7 hours, the dried carrier is firstly baked at 650 ℃ for 6 hours under nitrogen atmosphere, and then the alumina carrier is prepared by baking at 650 ℃ for 6 hours under oxygen atmosphere.

100 g of the alumina carrier is weighed and placed in a beaker, and 150 ml of the alumina carrier containing MoO is used ₃ 10 g of NiO1.2 g of molybdenum-nickel-phosphorus active metal impregnating solution impregnates the alumina carrier for 5 hours, redundant solution is filtered off, the impregnated material is dried for 6 hours at 120 ℃, and then is roasted for 5 hours at 500 ℃ to prepare a catalyst C1, and the properties of the catalyst are shown in Table 1.

Example 2

As in example 1, except that the amount of the basic aluminum ammonium carbonate added was 30 g, a 40wt% solution of tetrose in mass concentration was used for impregnating the basic aluminum ammonium carbonate, a 20wt% solution of mannitol in mass concentration was used for spraying the impregnated carrier, the amount of the solution was 20ml, the calcination temperature of the carrier under nitrogen and oxygen atmosphere was 700℃for 6 hours, and catalyst C2 was produced, and the properties of the catalyst were shown in Table 1.

Example 3

As in example 1, except that the amount of the added basic aluminum ammonium carbonate was 40 g, a glucose solution having a mass concentration of 30% was used for impregnating the basic aluminum ammonium carbonate, a pentose solution having a mass concentration of 10% was used for spray impregnation of the support, the amount of the solution was 15ml, the calcination temperature of the support under a nitrogen and oxygen atmosphere was 750℃and the calcination time was 6 hours, and catalyst C3 was obtained, and the properties of the catalyst were shown in Table 1.

Example 4

As in example 1, except that the amount of the added basic aluminum ammonium carbonate was 70 g, a fructose solution having a mass concentration of 25% was used for impregnating the basic aluminum ammonium carbonate, a mannitol solution having a mass concentration of 12.5% was used for spraying the impregnated carrier, and the amount of the solution was 17.5ml, catalyst C4 was produced, and the properties of the catalyst were shown in Table 1.

Example 5

As in example 1, except that the amount of the basic aluminum ammonium carbonate added was 60 g, an arabitol solution having a mass concentration of 35wt% was used for impregnating the basic aluminum ammonium carbonate, a mannitol solution having a mass concentration of 17.5wt% was used for spray impregnation of the molded carrier, and the amount of the solution was 17.5ml, to prepare a catalyst C5, the properties of which are shown in Table 1.

Comparative example 1

Comparative catalyst C6 was prepared as in example 1 except that the ammonium aluminum hydroxycarbonate and the shaped support were not impregnated with the carbon precursor solution, but the same amount of carbon precursor was added to the support in a kneaded form during shaping of the support, and the properties of the catalyst are shown in table 1.

Comparative example 2

Comparative catalyst C7 was obtained by calcining the support in an air atmosphere without two-stage calcination treatment as in example 1, and the properties of the catalyst are shown in Table 1.

TABLE 1 catalyst Properties

Note that: * Pore distribution refers to the percentage of pore volume in a range of diameters in a carrier to total pore volume.

The results in Table 1 show that the catalyst prepared by the method of the invention has a proper pore structure and high mechanical strength, and is suitable for the field of heavy residue ebullated bed hydrotreatment.

Example 6

The following examples illustrate the catalytic performance of the catalysts prepared by the process of the present invention and the comparative catalysts.

The catalysts of the above examples and comparative examples were evaluated for activity on a continuous stirred autoclave (CSTR), the catalyst loading was 100ml, and the ebullated bed reactor was similar to the continuous stirred autoclave (Continuous Stirred Tank Reactor, CSTR) with good total backmixing properties and opposite reaction kinetics. Thus, instead of ebullated bed reactors, CSTRs can be used to perform the catalyst performance. The properties of the raw oil are shown in Table 2, the evaluation conditions are shown in Table 3, the activity of the comparative catalyst C6 is taken as 100, and the activity evaluation results of the other catalysts are shown in Table 4.

TABLE 2 oil Properties of raw materials

Project
		Density (20 ℃), g/cm ³	1.01
Sulfur, wt%	3.51
		Carbon residue, wt%	20.86
Nickel+vanadium, μg/g	249

TABLE 3 Process conditions

Conditions (conditions)
		Reaction temperature, DEG C	430
Reaction pressure, MPa	15
		Airspeed, h ^-1	0.5

Table 4 comparative hydrogenation performance of catalysts

	C1	C2	C3	C4	C5	C6	C7
								Relative demetallization rate	123	126	118	109	113	100	101
Relative desulfurization rate	131	125	123	119	121	100	103
								Relative carbon residue removal rate	124	118	121	108	110	100	99

As can be seen from the data in Table 4, the catalyst prepared by the method of the invention has higher demetallization, desulfurization and carbon residue removal activities, and is suitable for the field of ebullated bed hydrodemetallization.

The fresh catalyst was tested for catalyst strength and attrition after 24 hours of reaction, and the test results are shown in fig. 1.

TABLE 5 catalyst strength and attrition

It can be seen from Table 5 that the catalyst prepared by the process of the present invention has higher strength and attrition resistance.

Claims

1. A method for preparing a ebullated bed hydroprocessing catalyst, comprising the steps of:

step (3), impregnating the alumina carrier obtained in the step (2) with impregnating solution containing hydrogenation active components, and drying and roasting the impregnated alumina carrier to obtain the ebullated bed hydrotreating catalyst;

the basic aluminum ammonium carbonate in the step (1) is basic aluminum ammonium carbonate with a rod-shaped structure, the length of the rod-shaped basic aluminum ammonium carbonate is 1-5 mu m, the diameter of the rod-shaped basic aluminum ammonium carbonate is 100-300nm, and the adding amount of the basic aluminum ammonium carbonate is 15-35 wt% of the weight of the pseudo-boehmite in the step (1);

the carbon precursor in the step (1) is polyalcohol and/or saccharide; the carbon precursor is adsorbed into basic aluminum ammonium carbonate in the form of a solution, the mass concentration of the carbon precursor solution is 20-40 wt%, the solution is used for completely immersing the basic aluminum ammonium carbonate, and the immersing time is 1-3 hours;

the carbon-containing precursor solution in the step (2) is an aqueous solution of polyalcohol and/or saccharide substances; the mass concentration of the carbon-containing precursor solution is 10-20wt%, and the dosage of the solution is 10-20wt% of the saturated absorption capacity of the molding material;

the roasting in the step (2) is two-stage roasting, firstly roasting is carried out under an inert atmosphere, the roasting temperature is 600-750 ℃, the roasting time is 4-8 hours, and the inert atmosphere is nitrogen, argon and other gases; then roasting in oxygen atmosphere at 600-750 deg.c for 4-8 hr;

in the step (3), in the hydrogenation active component impregnating solution, the content of the VIB group metal is 7-15g/100ml calculated by oxide, the content of the VIII group metal is 0.8-3g/100ml calculated by oxide, and the impregnation time is 1-5 hours by adopting an over-volume impregnation, equal-volume impregnation or spray impregnation mode.

2. The method for preparing an ebullated bed hydroprocessing catalyst according to claim 1, wherein the polyol in step (1) is one or more of xylitol, sorbitol, mannitol and arabitol;

the saccharide is one or more of glucose, ribose, fructose, triose, tetrose, pentose, hexose and hexose.

3. The method for preparing a catalyst for ebullated bed hydroprocessing according to claim 1, wherein in the step (1), a peptizing agent and/or an extrusion aid is added as needed during the kneading molding process;

the peptizing agent is one or more of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, oxalic acid and the like; the addition amount of the peptizing agent is 0.5 to 3 weight percent of the weight of the alumina carrier;

the extrusion assisting agent is sesbania powder, and the addition amount of the extrusion assisting agent is 0.1-0.5 wt% of the weight of the alumina carrier;

the drying temperature in the step (1) is 100-160 ℃, and the drying time is 6-10 hours.

4. The method for preparing an ebullated bed hydroprocessing catalyst according to claim 1, wherein the polyol in step (2) is one or more of xylitol, sorbitol, mannitol and arabitol;

5. The method for preparing an ebullated bed hydroprocessing catalyst according to claim 1, wherein the drying temperature in step (2) is 100-160 ℃ and the drying time is 6-10 hours.

6. The method for producing an ebullated bed hydroprocessing catalyst according to claim 1, wherein said drying condition in step (3) is drying at 80-120 ℃ for 6-10 hours; the roasting condition is that roasting is carried out for 3-6 hours at 400-600 ℃.