CN111821994B

CN111821994B - Preparation method of demetallization catalyst

Info

Publication number: CN111821994B
Application number: CN201910311725.5A
Authority: CN
Inventors: 季洪海; 凌凤香; 王少军; 张会成; 沈智奇
Original assignee: China Petroleum and Chemical Corp; Sinopec Dalian Research Institute of Petroleum and Petrochemicals
Current assignee: Sinopec Dalian Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Priority date: 2019-04-18
Filing date: 2019-04-18
Publication date: 2022-06-07
Anticipated expiration: 2039-04-18
Also published as: CN111821994A

Abstract

The invention discloses a preparation method of a demetallization catalyst, which comprises the following steps: (1) crushing the waste hydrotreating catalyst, and then roasting; (2) immersing the material obtained in the step (1) in an ammonium bicarbonate aqueous solution, sealing, performing heat treatment, filtering, drying the material, then immersing the material in a polyethylene glycol solution, filtering, and drying to obtain a pretreated material A; (3) kneading and molding the pseudoboehmite and the pretreatment material A, drying and roasting the molded product to obtain a carrier, and loading the hydrogenation active component on the carrier to obtain the demetallization catalyst. The method utilizes the waste catalyst to prepare the hydrodemetallization catalyst, reduces the production cost and environmental pollution, ensures the activity of the catalyst, ensures the good stability of the catalyst, and can prolong the running period of the device.

Description

Preparation method of demetalization catalyst

Technical Field

The invention relates to the field of catalyst preparation, in particular to a preparation method of a hydrodemetallization catalyst.

Background

With the deterioration and heaviness of crude oil, the efficient conversion of heavy oil and the improvement of the yield of light oil products become an important trend in the development of oil refining technology. The residue fixed bed hydrogenation technology is an effective means for realizing the high-efficiency conversion of heavy oil. By adopting the technical route, the impurities such as metal, sulfur, nitrogen, carbon residue and the like in the residual oil can be effectively removed, high-quality feed is provided for catalytic cracking, and the strict environmental protection regulation requirements are met while the yield of light oil products is increased. During the processing of heavy oil, the metal compounds therein are decomposed, and the metal impurities are deposited on the inner and outer surfaces of the catalyst to block the pore channels, even causing the catalyst to be poisoned and deactivated.

In the using process of the catalyst, the catalyst becomes waste due to the loss of the original activity, and the waste catalyst rich in metal is not used, so that resources are wasted and the environment is polluted. Recently, environmental regulations have increasingly stringent requirements for the disposal of spent catalysts. The waste catalyst is treated by several methods, such as landfill treatment, metal recovery, regeneration or recycling, and is used as a raw material to generate other useful products to solve the problem of the waste catalyst.

CN102441440A discloses a method for preparing a hydrotreating catalyst from a spent catalyst. Grinding the waste hydrotreating catalyst, adding alumina, a binder, an acid solution or an alkaline solution and other raw materials into the ground powder, kneading, molding, drying and roasting the molded sample to obtain the new hydrotreating catalyst. Although the method utilizes the waste catalyst to prepare the new hydrotreating catalyst, the pore volume 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 demetallization catalyst. The method utilizes the waste catalyst to prepare the hydrodemetallization catalyst, reduces the production cost and environmental pollution, ensures the activity of the catalyst, ensures the good stability of the catalyst, and can prolong the running period of the device.

The preparation method of the demetallization catalyst comprises the following steps:

(1) crushing the waste hydrotreating catalyst, and then roasting;

(2) immersing the material obtained in the step (1) in an ammonium bicarbonate aqueous solution, sealing, performing heat treatment, filtering, drying the material, then immersing the material in a polyethylene glycol solution, filtering, and drying to obtain a pretreated material A;

(3) kneading and molding the pseudoboehmite and the pretreatment material A, drying and roasting the molded product to obtain a carrier, and loading the hydrogenation active component on the carrier to obtain the demetallization catalyst.

In the method of the present invention, the spent hydrotreating catalyst in step (1) refers to a hydrotreating catalyst such as hydrodesulfurization, denitrification, etc. of distillate oil and residual oil which has not achieved the reaction requirement or has not been completely deactivated due to gradation. The hydrotreating catalyst contains hydrogenation active metal, the active metal is one or more of VIB and VIII group metals, and the waste hydrotreating catalyst contains sulfide and alumina of the active metal, and also contains other oxides such as titanium oxide, silicon oxide, boron oxide, molecular sieves and the like, and impurities such as carbon deposition, heavy metals and the like. The active metal content on the spent hydroprocessing catalyst is typically from 1wt% to 40wt% of the catalyst weight and the metal impurities are typically from 0.1wt% to 30 wt%. The shape is generally cylindrical, spherical or multi-lobed. The waste hydrotreating catalyst is crushed to be more than 200 meshes, and preferably 400-800 meshes. The roasting temperature is 700-950 ℃, and the roasting time is 6-12 hours.

In the method, the dosage of the ammonium bicarbonate aqueous solution in the step (2) is at least the dosage of the material obtained in the step (1) immersed; the mass percentage concentration of the ammonium bicarbonate aqueous solution is 15-25%.

In the method of the invention, the sealing heat treatment temperature in the step (2) is 120-180 ℃, preferably 120-160 ℃, and the treatment time is 4-8 hours.

In the method of the present invention, the drying conditions in step (2) are as follows: the drying temperature is 100-160 ℃, and the drying time is 6-10 hours.

In the method of the invention, the average molecular weight of the polyethylene glycol in the step (2) is 2000-12000, the dosage of the polyethylene glycol solution is at least to immerse the heat-treated material, the soaking time is 1-2 hours, and the mass percent concentration of the polyethylene glycol solution is 20-40%.

According to the method, the pretreated material A in the step (2) is of a mutually staggered columnar structure, the length of the columnar structure is 0.5-2 mu m, and the diameter of the columnar structure is 50-200 nm.

In the method, the mass ratio of the pretreatment material A in the step (3) to the pseudo-boehmite is 1:5-1: 2.

In the method of the invention, the kneading molding in the step (3) is carried out by adopting a conventional method in the field, and in the molding process, conventional molding aids, such as one or more of peptizing agents, extrusion aids and the like, can be added according to the needs. The peptizing agent is one or more of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, oxalic acid and the like; the extrusion aid is sesbania powder. The drying temperature is 100-160 ℃, and the drying time is 6-10 hours; the roasting temperature is 600-750 ℃, and the roasting time is 4-6 hours; the calcination is carried out in an oxygen-containing atmosphere, preferably an air atmosphere.

In the method of the present invention, the supporting mode in the step (3) may be a mode of supporting when the carrier is kneaded, or a mode of impregnating the carrier, preferably a mode of impregnating the carrier. The adopted impregnation liquid containing the hydrogenation active metal component is a solution containing VIB group and/or VIII group metals, the VIB group metal is selected from one or more of W, Mo, the VIII group metal is selected from one or more of Co and Ni, the content of the VIB group metal is 8-15g/100mL calculated by metal oxides, the content of the VIII group metal is 2.5-4.0g/100mL calculated by metal oxides, and equal-volume impregnation or supersaturated impregnation can be adopted during impregnation. After the impregnation, drying and roasting are generally carried out, wherein the drying temperature is 80-160 ℃, the drying time is 6-10 hours, and the roasting is carried out at the temperature of 450-550 ℃ for 4-8 hours.

Compared with the prior art, the invention has the following advantages:

(1) the invention takes the waste hydrogenation catalyst as the raw material, obtains the staggered columnar structure through the simple pretreatment process, forms larger through pore channels by forming with the pseudo-boehmite and dispersing in the carrier, the pore channels are mutually communicated, the mass transfer and the diffusion of macromolecular reactants are facilitated, and the columnar structure has higher metal capacity, the active metal in the waste catalyst is further concentrated by the columnar structure, simultaneously, more surfaces of the columnar structure are exposed, and more active sites are increased by further loading the active components, thereby not only ensuring that the catalyst has higher activity, but also ensuring that the catalyst has good stability, and prolonging the operation period of the device.

(2) The polyethylene glycol solution in the invention has the following soaking treatment effects: due to the existence of the polyethylene glycol, a good skeleton supporting effect is achieved, and macroporous channels in the staggered columnar structure of the pretreated materials are well maintained when the carrier is molded. In addition, the gas generated by the decomposition of polyethylene glycol during roasting can play a role in hole expansion.

(3) The method is simple, and uses partial waste catalyst to replace alumina raw material, thereby changing waste into valuable, reducing production cost and reducing environmental pollution.

Drawings

FIG. 1 is an SEM photograph of pretreated feedstock A prepared in example 1.

FIG. 2 is an SEM photograph of pretreated batch A prepared in comparative example 1.

Detailed Description

The technical solutions and effects of the present invention are further described below with reference to the following examples, but the present invention is not limited to the following examples. Wt% in the present invention represents a mass fraction.

The BET method: application N₂Physical adsorption-desorption characterization of the pore structures of the carriers of the examples and the comparative examples, the specific operations are as follows: adopting ASAP-2420 type N₂And the physical adsorption-desorption instrument is used for characterizing the pore structure of the sample. Taking a small amount of samples, carrying out vacuum treatment for 3-4 hours at 300 ℃, and finally placing the product under the condition of liquid nitrogen low temperature (-200 ℃) to carry out nitrogen absorption-desorption test. Wherein the specific surface area is obtained according to a BET equation, and the distribution rate of the pore volume and the pore diameter below 30nm is obtained according to a BJH model.

Mercury pressing method: the pore diameter distribution of the carriers of the examples and the comparative examples is characterized by applying a mercury porosimeter, and the specific operation is as follows: sample alignment is carried out by adopting an American microphone AutoPore9500 type full-automatic mercury intrusion gaugeAnd (5) characterizing the pin hole distribution. The samples were dried, weighed into an dilatometer, degassed for 30 minutes while maintaining the vacuum conditions given by the instrument, and filled with mercury. The dilatometer was then placed in the autoclave and vented. And then carrying out a voltage boosting and reducing test. The mercury contact angle is 130 degrees, and the mercury interfacial tension is 0.485N.cm^-1The distribution ratio of the pore diameter of 100nm or more is measured by mercury intrusion method.

A scanning electron microscope is used for representing the microstructure of the alumina carrier, and the specific operation is as follows: and a JSM-7500F scanning electron microscope is adopted to represent the microstructure of the carrier, the accelerating voltage is 5KV, the accelerating current is 20 muA, and the working distance is 8 mm.

The method adopts NB/SH/T0704-.

The sulfur content in the oil product is determined by adopting an SH/T0689-.

The content of carbon residue in the oil product is determined by adopting an SH/T0266-92 standard method.

And the contents of Ni and V in the oil product are determined by adopting a GB/T34099-2017 standard method.

The waste catalyst used in the examples is the waste catalyst (containing MoO) of fixed bed residue oil hydrogenation industrial device₃：5%，NiO：8.3%，V₂O₅：17.8%，Fe₂O₃：1.6%，Al₂O₃: 52.4, C: 14.9%), extracted to remove oil on the surface of the catalyst and dried.

Example 1

(1) Taking the waste catalyst crushed to more than 230 meshes, and roasting at 750 ℃ for 8 hours;

(2) weighing 50 g of the waste catalyst, placing the waste catalyst into 300 g of ammonium bicarbonate aqueous solution with the mass percent concentration of 18%, transferring the mixed material into a high-pressure kettle, and carrying out sealed heat treatment under the following heat treatment conditions: the powder was heated at 140 ℃ for 6 hours and then dried at 110 ℃ for 6 hours. Soaking the mixture in 25 wt% concentration polyglycol-6000 solution of molecular weight 6000 for 1.5 hr, filtering, and drying at 120 deg.c for 6 hr to obtain pre-treated material A;

(3) weighing 100 g of pseudo-boehmite, 30 g of pretreated material A and 1.5 g of sesbania powder, uniformly mixing the materials, and addingKneading a proper amount of aqueous solution in which 3 g of acetic acid is dissolved, extruding into strips, forming, drying the formed product at 140 ℃ for 6 hours, and roasting at 700 ℃ in the air for 5 hours to obtain a carrier; the support is treated with a Mo-Ni-P solution (so that the final catalyst contains MoO)₃10.6wt% and 3.2wt% of NiO), filtering off the excessive solution, drying at 120 ℃, and roasting at 450 ℃ for 5 hours to obtain the catalyst Cat-1, wherein the properties of the catalyst are shown in Table 1.

Example 2

In the same way as example 1, except that the mass percent concentration of ammonium bicarbonate is 21%, the heat treatment temperature is 120 ℃, the heat treatment time is 8 hours, polyethylene glycol-2000 (molecular weight is 2000) solution is used, and the mass percent concentration is 30%. The amount of the pretreatment feed A added was 45 g, and catalyst Cat-2 was prepared, the catalyst properties of which are shown in Table 1.

Example 3

The same as example 1 except that the calcination temperature of the spent catalyst powder was 900 ℃. The ammonium bicarbonate solution has a mass percent concentration of 15%, a heat treatment temperature of 160 ℃ and a heat treatment time of 4 hours, and polyethylene glycol-12000 (i.e. a molecular weight of 12000) solution is used instead, and the mass percent concentration is 20%. The amount of the pretreatment feed A added was 20 g, and the catalyst Cat-3 was prepared, the properties of which are shown in Table 1.

Example 4

The same as example 1, except that the ammonium bicarbonate solution was 25% by weight. The heat treatment temperature was 150 ℃ and the heat treatment time was 7 hours. The mass percentage concentration of the polyethylene glycol-6000 solution is 40 percent. The amount of pretreatment feed A added was 40 g to obtain catalyst Cat-4, the catalyst properties are shown in Table 1.

Comparative example 1

A comparative catalyst Cat-5 was prepared as in example 1 except that the ammonium bicarbonate solution was at a concentration of 10% by weight, and the catalyst properties are shown in Table 1.

Comparative example 2

A comparative catalyst Cat-6 was prepared as in example 1 except that the hydrothermal treatment temperature was 100 ℃ and the catalyst properties were as shown in Table 1.

Comparative example 3

The same as example 1 except that the treatment process of step (2) is omitted; catalyst Cat-7 was prepared, with catalyst properties as shown in Table 1.

Comparative example 4

Catalyst Cat-8 was prepared in the same manner as in example 1 except that the immersion treatment of the polyvinyl alcohol solution was not conducted in step (2), and the catalyst properties are shown in Table 1.

TABLE 1 catalyst Properties

Evaluation of catalytic performance:

the hydrodemetallization catalyst (Cat-1-Cat-8) prepared above was evaluated for catalytic performance by the following method:

the vacuum residue listed in Table 2 was used as a raw material, the catalytic performance of Cat-1-Cat-8 was evaluated on a fixed bed residue hydrogenation reactor, the catalyst was a 2-3 mm long strip, and the reaction conditions were as follows: the reaction temperature is 387 ℃, the hydrogen partial pressure is 15.7MPa, and the liquid hour volume space velocity is 1.0 hour^-1The volume ratio of hydrogen to oil is 758, the content of each impurity in the produced oil is measured after 1500 hours of reaction, the impurity removal rate is calculated, and the evaluation result is shown in table 3.

TABLE 2 Properties of the feed oils

TABLE 3 comparison of catalyst hydrogenation performance

Claims

1. The preparation method of the demetallization catalyst is characterized by comprising the following steps of: (1) crushing the waste hydrotreating catalyst, and then roasting; (2) immersing the material obtained in the step (1) in an ammonium bicarbonate aqueous solution, sealing, performing heat treatment, filtering, drying the material, then immersing the material in a polyethylene glycol solution, filtering, and drying to obtain a pretreated material A; (3) kneading and molding pseudo-boehmite and the pretreatment material A, drying and roasting a molded product to obtain a carrier, and loading a hydrogenation active component on the carrier to obtain a demetallization catalyst; the waste hydrotreating catalyst in the step (1) comprises active metal sulfide and an alumina carrier; the active metal is one or more of VIB and VIII group metals; the active metal content on the spent hydroprocessing catalyst is 1wt% to 40wt% of the weight of the catalyst; the dosage of the ammonium bicarbonate aqueous solution in the step (2) is at least that the material obtained in the step (1) is immersed; the mass percentage concentration of the ammonium bicarbonate aqueous solution is 15-25%; the sealing heat treatment temperature in the step (2) is 120-180 ℃, and the treatment time is 4-8 hours; and (3) pretreating the material A in the step (2) to form a staggered columnar structure, wherein the length of the columnar structure is 0.5-2 mu m, and the diameter of the columnar structure is 50-200 nm.

2. The method of claim 1, wherein: the roasting temperature in the step (1) is 700-950 ℃, and the roasting time is 6-12 hours.

3. The method of claim 1, wherein: the drying conditions in the step (2) are as follows: the drying temperature is 100-160 ℃, and the drying time is 6-10 hours.

4. The method of claim 1, wherein: the average molecular weight of the polyethylene glycol in the step (2) is 2000-12000, the dosage of the polyethylene glycol solution is at least to immerse the heat-treated materials, the soaking time is 1-2 hours, and the mass percent concentration of the polyethylene glycol solution is 20-40%.

5. The method of claim 1, wherein: the mass ratio of the pretreatment material A to the pseudo-boehmite in the step (3) is 1:5-1: 2.

6. The method of claim 1, wherein: the drying temperature in the step (3) is 100-160 ℃, and the drying time is 6-10 hours; the roasting temperature is 600-750 ℃, and the roasting time is 4-6 hours.