CN113430004B

CN113430004B - Inferior catalytic diesel oil hydrotreating method

Info

Publication number: CN113430004B
Application number: CN202010209917.8A
Authority: CN
Inventors: 王延飞; 张雅琳; 赵梓贺; 袁晓亮; 张占全; 付凯妹; 庄梦琪; 余颖龙; 谢彬; 王燕; 王嘉祎; 王晶晶
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2020-03-23
Filing date: 2020-03-23
Publication date: 2023-02-28
Anticipated expiration: 2040-03-23
Also published as: CN113430004A

Abstract

The invention discloses a poor-quality catalytic diesel oil hydrotreating method. The process involves the direct grading combination of three different types of catalysts, namely a conventional calcined type I catalyst, a type II catalyst containing an organic promoter, and a mixed type I/II catalyst. The poor diesel oil feed firstly flows through the I type catalyst, then the effluent contacts with the II type catalyst containing the organic assistant, and finally contacts with the I/II mixed type catalyst, so that the aim of deeply removing the sulfur and nitrogen impurities is achieved, and the stability of the catalyst is improved.

Description

Inferior catalytic diesel oil hydrotreating method

Technical Field

The invention relates to a poor-quality catalytic diesel oil hydrotreating method, in particular to a hydrotreating method suitable for high-nitrogen poor-quality catalytic diesel oil raw materials.

Background

The diesel oil hydrotreating process is one process of eliminating impurity and saturating arene with diesel oil and hydrogen in certain temperature and pressure condition and through contact with catalyst. At present, the method for desulfurizing, denitrifying and dearomatizing diesel oil fraction generally adopts two-stage method, i.e. first stage of hydrogenation desulfurization and denitrification, and second stage of hydrogenation dearomatization. Conventional hydrodesulfurization and denitrogenation catalysts generally comprise a carrier and a group VIB and/or group VIII active metal component loaded on the carrier, wherein the most common group VIB metals are molybdenum and tungsten, and the group VIII metals are nickel and cobalt, and the catalysts also often contain auxiliary agents such as phosphorus, boron and the like. The catalyst is generally prepared by supporting the active component on a support, for example by impregnation, and then converting it to the oxidized state by drying and calcination at high temperature. The catalyst is presulfided to convert it to the sulfided state prior to use in hydroprocessing. Therefore, a large amount of energy is wasted, the cost of the catalyst is increased, and the catalyst performance is reduced because some non-ideal phases with low or even no activity are formed by high-temperature roasting after the active metal is loaded.

It is reported that the organic compound is added into the metal impregnation liquid and impregnated on the porous carrier, so that more high-activity II-type active phase can be generated, and simultaneously, the activity loss caused by metal aggregation in the high-temperature vulcanization process of the catalyst can be prevented, thereby improving the activity of the hydrotreating catalyst. A number of patents disclose the use of various organic compounds, such as oxygen-containing organic compound polyols or etherates thereof (WO 96/41848, US3954673, US 4012340).

Patent JP 04166231 discloses a preparation method of hydrotreating catalyst, which comprises impregnating a porous carrier with a metal solution, drying at a temperature of not higher than 200 ℃, and subjecting the dried carrier to a drying step after contacting with a polyhydroxy compound. EP 0601722 discloses a preparation method of a catalyst, which is characterized in that a porous alumina carrier is impregnated by a metal aqueous solution containing dihydric alcohol, and the impregnated carrier is subjected to a primary drying step without a roasting process to prepare a finished catalyst.

US 6218333 discloses a process for preparing a hydroprocessing catalyst by combining a porous support with an active metal component to form a catalyst precursor having volatiles. The catalyst precursor is treated with a sulfur-containing compound, and volatiles are released from the catalyst precursor under dry conditions. However, these improvements are not sufficient to meet the increasingly stringent fuel requirements of refineries.

Patent application US 2011/0079542 discloses that replacing a portion of the reference HDS catalyst with a catalyst having a lower activity at the front of the bed compared to the 100% reference does not change the performance of the entire charge, since in the same portion of the catalytic bed, the reaction takes place on non-tolerant sulfur-containing species, without the need for a high-performance catalyst.

Patent CN105985805A discloses the advantage of combining catalysts with particles of different sizes and shapes, depending on the secondary formulation.

Disclosure of Invention

The invention aims to provide a method for hydrotreating poor-quality catalytic diesel. The method relates to the hydrotreatment of poor-quality catalytic diesel oil by using a specific grading combination of three different types of catalysts, and compared with a hydrotreatment method using the same quantity and the same operating conditions as one or two of the three types of catalysts, the method can improve the activity of the hydrotreatment process, and can deeply remove heterocyclic compounds such as sulfur, nitrogen and the like in the poor-quality catalytic diesel oil to realize the production of low-sulfur and low-nitrogen diesel oil.

In order to realize the aim, the invention provides a poor-quality catalytic diesel oil hydrotreating method, which comprises the following steps:

(1) The method comprises the following steps that feeding of poor-quality catalytic diesel oil is in contact reaction with a first catalyst, wherein the first catalyst is an I-type catalyst prepared by an alumina carrier, phosphorus and metal active components through high-temperature roasting by adopting an impregnation method, and the metal active components comprise at least one metal selected from VIB group and one metal selected from VIII group;

(2) Contacting the effluent obtained in the step (1) with a second catalyst for reaction, wherein the second catalyst is a II-type catalyst prepared by adopting an alumina carrier, an organic auxiliary agent, phosphorus and a metal active component by an impregnation method without high-temperature roasting, and the metal active component is composed of at least one metal selected from VIB group and at least one metal selected from VIII group;

(3) And (3) enabling the effluent in the step (2) to mutually contact and react with a third catalyst, wherein the third catalyst is an I/II type catalyst prepared by adopting a step-by-step impregnation method, namely roasting an alumina carrier impregnated with a solution containing a metal active component and a phosphorus element, then impregnating with a solution containing the metal active component, the phosphorus element and an organic auxiliary agent, and drying to obtain the catalyst, wherein the metal active component is prepared from at least one metal selected from a VIB group and at least one metal selected from a VIII group.

The invention can also be detailed as follows:

the invention provides a method for hydrotreating poor-quality catalytic diesel, which is based on specific grading combination of three different types of catalysts and comprises the following steps:

a) The method comprises the following steps that (1) feeding of poor-quality diesel oil is contacted with a first catalyst, wherein the first catalyst is a calcined I-type catalyst and comprises an alumina carrier, phosphorus and a metal active component; the metal active component consists of at least one metal from group VIB and one metal from group VIII.

b) Contacting the effluent obtained in step a) with a second catalyst, wherein the second catalyst belongs to a roasting-free process II type catalyst, and an organic auxiliary agent is added in the preparation process, and the catalyst comprises an alumina carrier, phosphorus and a metal active component; the metal active component consists of at least one metal from group VIB and one metal from group VIII.

c) And c) mutually contacting the effluent in the step b) with a third catalyst, wherein the third catalyst is an I \ II type catalyst, and is obtained by roasting an alumina carrier impregnated with a solution containing a metal active component and a phosphorus element, impregnating with a solution containing the metal active component, the phosphorus element and an organic auxiliary agent, and drying.

In the invention, the alumina carrier refers to a carrier with the alumina content of more than 70 mass percent, and can be a modified alumina carrier, and the crystal form of the alumina can be gamma, theta or the mixed crystal form. The calcination temperature of the catalyst is preferably 450 to 550 ℃ and preferably 450 to 500 ℃.

The metal active component of the present invention is a metal commonly used in the art, such as a group VIB metal preferably selected from molybdenum and/or tungsten, and a group VIII metal preferably selected from cobalt and/or nickel.

The metal active components of the first and second catalysts may be the same or different, and it is recommended to use different metal active components, in particular metals of group VIII, preferably with a composition: niMoP type, coMoP type.

Due to the characteristics of the raw materials, the more preferable scheme is as follows: the first catalyst was a NiMoP catalyst and the second catalyst was a CoMoP catalyst.

The first catalyst is a type I catalyst prepared after roasting, and means that the preparation process of the catalyst adopts a common preparation method of an impregnated catalyst: impregnating the carrier with a solution containing metals of VIB group and VIII group and phosphorus element, drying after impregnation, and roasting.

The second catalyst belongs to a II type catalyst without roasting process, which means that in the preparation process of the catalyst, an organic auxiliary agent is added into a solution containing metals of VIB group and VIII group and phosphorus elements, and the II type catalyst is obtained by dipping and drying.

The metal active components added twice in the third catalyst can be the same or different and are selected according to the characteristics of raw materials and processing requirements, and preferably, the metal active component for the first time contains Ni and Mo, and the metal active component for the second time contains Co and Mo.

In the present invention, the organic auxiliary is preferably alcohols and/or organic acids, such as ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, polyethylene glycol, citric acid, malic acid, tartaric acid. Polyethylene glycol and citric acid are preferred.

The carriers of the three catalysts of the invention may be the same or different.

More specifically, the preferred first catalyst preparation comprises the steps of:

i, preparing a porous carrier based on alumina or a phosphorus-containing alumina material;

and ii, impregnating the porous carrier with NiMoP solution containing Ni, mo and P elements, curing, drying, and roasting at 450-500 ℃ for 2-4 hours to obtain the final type I catalyst.

The second catalyst preparation comprises the following steps:

and step II, impregnating the porous carrier with a II-type NiMoP metal solution containing organic auxiliary agent alcohols and/or organic acids, curing and drying without roasting to obtain the final II-type catalyst.

The third catalyst preparation comprises the following steps:

and step II, impregnating the porous carrier with a NiMoP solution containing Ni, mo and P elements, curing, drying, roasting for 2-4 hours at 450-500 ℃, impregnating the porous carrier with a II-type NiMoP metal solution containing organic auxiliary agent alcohols and/or organic acids, curing, drying, and obtaining the I/II-type catalyst without roasting.

The active metal component of each of the three catalysts of the invention, the amount of the metal selected from group VIB being from 20% to 30% by weight, the amount of the metal selected from group VIII being from 3% to 5% by weight, based on the total weight of the catalyst, of the oxide of the metal selected from group VIII, and the amount of phosphorus being in the range of from 3% to 5% by weight, based on the total weight of the catalyst, of P ₂ O ₅ 。

In the present invention, step a) is carried out in a volume V ₁ In a first zone containing a first catalyst, step b) being carried out in an occupation volume V ₂ In a second zone containing a second catalyst, step c) being carried out in an occupation volume V ₃ In a third zone containing a third catalyst. Volume distribution ratio V ₁ /V ₂ /V ₃ Preferably from 5 to 20%/10 to 20%/60 to 85% each.

In the invention, the three catalysts have the single activities of a first catalyst, a second catalyst and a third catalyst in sequence from low to high. Since the feed is contacted with a first catalyst of type I, then with a second catalyst of type II, and finally flows over a catalyst of the mixed type I/II. The second and third catalysts are less inhibited by nitrogen-containing molecules and are therefore more active and stable over time. The first catalyst and the second catalyst respectively play a role in protecting the third catalyst in sequence.

In the invention, the poor diesel oil feed firstly flows through the I-type catalyst, then the effluent contacts with the II-type catalyst containing the organic auxiliary agent, and finally contacts with the I/II mixed catalyst, thereby achieving the purpose of deeply removing the sulfur and nitrogen impurities and simultaneously improving the stability of the catalyst.

Detailed Description

The technical solutions of the present invention are described in detail below with reference to specific examples so as to facilitate understanding of the objects and technical contents of the present invention, and the embodiments are only for illustration and are not intended to limit the present invention.

The following examples demonstrate that a hydroprocessing process using a combination of calcined type I catalyst, type II catalyst and developed type I/II mixed catalyst grading results in improved activity when hydroprocessing a poor quality catalytic diesel fuel compared to the use of calcined type I catalyst alone or the use of type II catalyst alone or the use of developed type I/II mixed catalyst alone.

Firstly, preparing catalysts A, B, C and D, wherein the preparation method comprises the following steps:

catalyst A: a calcined NiMoP/alumina type I catalyst;

the pseudo-boehmite is adopted to extrude strips, dried and roasted at 550 ℃ to prepare 70g of clover-shaped A12O3 carrier strips. Molybdenum trioxide (24 g), basic nickel carbonate (8 g), and 85% phosphoric acid (8 g) were thermally dissolved in a hot phosphoric acid solution to prepare a NiMoP solution. Adding NiMoP solution into the carrier, soaking, aging the extrudate at room temperature for 6 hr, drying at 120 deg.c overnight, and roasting at 450 deg.c for 2 hr to obtain catalyst A.

Catalyst B: a NiMoP/alumina type II catalyst;

extruding pseudo-boehmite into strips, drying and roasting at 550 ℃ to prepare 70g of clover-shaped A12O3 carrier; molybdenum trioxide (24 g), basic nickel carbonate (8 g), and 85% phosphoric acid (8 g) were thermally dissolved in a hot phosphoric acid solution to prepare a NiMoP solution. The NiMoP-CA (citric acid) -PEG (polyethylene glycol molecular weight is 2000) mixed solution is soaked in the catalyst precursor, then is cured for 6 hours at room temperature, and is dried for 6 hours at 100-260 ℃ to obtain the II type catalyst B.

Catalyst C: a CoMoP/NiMoP/alumina I/II mixed type catalyst;

extruding pseudo-boehmite into strips, drying and roasting at 550 ℃ to prepare 70g of clover-shaped A12O3 carrier; molybdenum trioxide (24 g), cobalt hydroxide (2.3 g), and 85% phosphoric acid were heat-dissolved in a hot phosphoric acid solution to prepare a CoMoP solution. Adding the mixed solution of CoMoP into the carrier, impregnating, aging the extrudate at room temperature for 6 hours, drying at 120 ℃, and roasting at 450 ℃ for 2 hours to obtain the catalyst precursor.

A NiMoP solution was prepared by heat-dissolving molybdenum trioxide (24 g), basic nickel carbonate (5 g), and 85% phosphoric acid in a hot phosphoric acid solution. And (3) soaking the catalyst precursor in mixed NiMoP-CA-PEG solution with the molecular weight of 2000, curing at room temperature for 6 hours, and drying at 100-260 ℃ for 6 hours to obtain the I/II type CoMo/NiMo catalyst C.

Catalyst D: niMoP/CoMoP/alumina I/II mixed type catalyst;

extruding pseudo-boehmite into strips, drying and roasting at 550 ℃ to prepare 70g of clover-shaped A12O3 carrier; molybdenum trioxide (24 g) and basic nickel carbonate (5 g) 85% phosphoric acid were thermally dissolved in a hot phosphoric acid solution to prepare a NiMoP solution. Adding the NiMoP mixed solution into the carrier, curing the extrudate at room temperature for 6 hours after dipping, drying at 120 ℃, and roasting at 450 ℃ for 2 hours to obtain the catalyst precursor.

Molybdenum trioxide (24 g), cobalt hydroxide (2.3 g), and 85% phosphoric acid were heat-dissolved in a hot phosphoric acid solution to prepare a CoMoP solution. After the catalyst precursor is soaked in a mixed solution of CoMoP-CA-PEG (polyethylene glycol molecular weight of 2000), the mixture is aged for 6 hours at room temperature and dried for 6 hours at 100-260 ℃, and the I/II type NiMo/CoMo catalyst D is obtained.

Evaluating various grading combinations of catalysts A, B, C and D in the hydrogenation treatment of poor-quality catalytic diesel oil:

the poor catalytic diesel oil has the following characteristics: 0.923 density (20 ℃), 1060ppm nitrogen content, 1.21wt% sulfur content and 84wt% aromatic hydrocarbon content.

Simulated distillation:

IP：160℃

5％：210℃

10％：229℃

50％：290℃

70％：315℃

90％：343℃

the tests were carried out in an isothermal pilot reactor with a fixed flushing bed, comprising three catalytic zones, for evaluating various grading combinations of catalysts a, B, C and D. The feed initially passes through a first zone containing a first catalyst, subsequently passes through a second zone containing a second catalyst, and finally passes through a third zone containing a third catalyst.

Comparative example 1

The three catalytic zones completely (100% by volume) contained calcined NiMoP/alumina type I catalyst.

Comparative example 2

The three catalytic zones completely (100% by volume) contain a NiMoP/alumina type II catalyst containing an organic promoter.

Comparative example 3

The three catalytic zones contained completely (100% by volume) a Co/NiMoP/alumina I/II mixed type catalyst.

Comparative example 4

The first zone was packed with calcined NiMoP/alumina type I catalyst (catalyst a: 30% by volume), followed by the second, three zones with organic promoter-containing type II catalyst (catalyst B: 70% by volume).

Example 1

The first zone was packed with calcined NiMoP/alumina type I catalyst (catalyst a: 10% by volume), followed by the second zone with organic promoter containing type II catalyst (catalyst B: 20% by volume). The third zone was then loaded with a Co/NiMoP/alumina I/II mixed type catalyst (catalyst C: 70% by volume).

Example 2

The first zone was packed with calcined NiMoP/alumina type I catalyst (catalyst a: 10% by volume), followed by the second zone with organic promoter containing type II catalyst (catalyst B: 30% by volume). The third zone was then loaded with Co/NiMoP/alumina I/II mixed type catalyst (catalyst D: 60% by volume).

The temperature corresponding to the nitrogen content of 10ppm obtained at the reactor outlet represents the activity of the combined catalyst. The table below shows the temperatures required to obtain a nitrogen content of 10ppm for the various combinations of gradations of catalysts A, B, C, D.

The results show that 3 catalysts were loaded in 3 different zones according to the combination of example 1 of the process of the invention, this graded combination being the most active. The temperature required to obtain a 10ppm content of N at the outlet of the reactor is given in Table 1 below.

TABLE 1

Claims

1. A poor-quality catalytic diesel oil hydrotreating method is characterized by comprising the following steps:

(1) The method comprises the following steps that feeding of poor-quality catalytic diesel oil is in contact reaction with a first catalyst, wherein the first catalyst is an I-type catalyst prepared by carrying out high-temperature roasting on an alumina carrier, phosphorus and metal active components by adopting an impregnation method, and the metal active components are Ni and Mo;

(2) Enabling the effluent obtained in the step (1) to contact and react with a second catalyst, wherein the second catalyst is a II-type catalyst prepared by adopting an alumina carrier, an organic auxiliary agent, phosphorus and metal active components by an impregnation method without high-temperature roasting, and the metal active components are Ni and Mo;

(3) Enabling the effluent in the step (2) to mutually contact and react with a third catalyst, wherein the third catalyst is an I/II mixed type catalyst prepared by adopting a step-by-step impregnation method, namely roasting an alumina carrier impregnated by a solution containing a metal active component and a phosphorus element, then impregnating by a solution containing the metal active component, the phosphorus element and an organic auxiliary agent, and drying to obtain the catalyst, wherein the metal active component is Ni, mo and Co;

wherein the nitrogen content in the poor catalytic diesel oil is 1000-2500ppm;

wherein, the first catalyst is NiMoP/alumina I type, and the preparation method comprises the following steps:

step i: preparing a porous support based on alumina or on a phosphorus-containing alumina;

step ii: impregnating the porous carrier with NiMoP solution containing Ni, mo and P elements, curing, drying, and roasting at 400-600 ℃ for 2-4 hours to obtain a first catalyst;

wherein the second catalyst is NiMoP/alumina II type, and the preparation method comprises the following steps:

step ii: impregnating the porous carrier with a NiMoP metal solution containing an organic auxiliary agent, curing and drying at room temperature without a roasting process and a high-temperature activation process to obtain a second catalyst;

wherein the third catalyst is a CoMoP/NiMoP/alumina I/II mixed type catalyst or a NiMoP/CoMoP/alumina I/II mixed type catalyst;

the preparation method of the I/II mixed type catalyst of CoMoP/NiMoP/alumina comprises the following steps:

step i: preparing a porous carrier based on silicon-modified alumina;

step ii: soaking the porous carrier by using a CoMoP solution containing Co, mo and P elements, curing, drying, and roasting at 400-600 ℃ for 2-4 hours to obtain a catalyst intermediate;

step iii: dipping the catalyst intermediate obtained in the step ii by using a NiMoP metal solution containing an organic auxiliary agent, curing and drying to obtain a third catalyst without a roasting process;

the preparation method of the NiMoP/CoMoP/alumina I/II mixed type catalyst comprises the following steps:

step i: preparing a porous carrier based on silicon-modified alumina;

step ii: impregnating the porous carrier with NiMoP solution containing Ni, mo and P elements, curing, drying, and roasting at 400-600 ℃ for 2-4 hours to obtain a catalyst intermediate;

step iii: dipping the catalyst intermediate obtained in the step ii by using a CoMoP metal solution containing an organic auxiliary agent, curing and drying to obtain a third catalyst without roasting;

wherein the activities of the first catalyst, the second catalyst and the third catalyst are sequentially from low to high;

wherein the step (1) is carried out in an occupied volume V ₁ In a first zone containing a first catalyst;

said step (2) is carried out in an occupied volume V ₂ In a second zone containing a second catalyst;

said step (3) is carried out in an occupied volume V ₃ In a third zone containing a third catalyst;

wherein the occupied volume V ₁ /V ₂ /V ₃ The distribution ratio of the components is 5-20%/10-20%/60-85%.

2. The method for hydrotreating poor quality catalytic diesel oil according to claim 1, wherein in step (1) or step (2), the alumina carrier is a modified or unmodified carrier having an alumina content of more than 70wt%, wherein the alumina has a crystal form selected from at least one of γ -type and θ -type.

3. The method for hydrotreating poor quality catalytic diesel oil according to claim 1, wherein in the first catalyst, the mass of Mo is 20-30% of the total mass of the catalyst, the mass of Ni is 3-5% of the total mass of the catalyst based on the mass of the oxide, and the mass of phosphorus is P ₂ O ₅ Calculated by 3 to 5 percent of the total mass of the catalyst; in the second catalyst, the mass of Mo accounts for 20-30% of the total mass of the catalyst, and the mass of Ni is oxidized3-5% of the total mass of the catalyst, P being P ₂ O ₅ Calculated by 3 to 5 percent of the total mass of the catalyst; in the third catalyst, the mass of Mo accounts for 20-30% of the total mass of the catalyst, the mass of Ni and Co accounts for 3-5% of the total mass of the catalyst by the mass of an oxide, and phosphorus accounts for P ₂ O ₅ Calculated by 3 to 5 percent of the total mass of the catalyst.

4. The method for hydrotreating poor quality catalytic diesel oil according to claim 1, characterized in that in step (1) or step (3), the roasting temperature is 450-550 ℃.

5. The method for hydrotreating poor quality catalytic diesel oil according to claim 4, characterized in that in step (1) or step (3), the roasting temperature is 450-500 ℃.

6. The method for hydrotreating poor quality catalytic diesel oil according to claim 1, characterized in that in the second catalyst or the third catalyst, the organic auxiliary agent is selected from alcohols and/or organic acids.

7. The method for hydrotreating poor quality catalytic diesel oil according to claim 6, characterized in that the alcohol is selected from at least one of ethylene glycol, propylene glycol, butylene glycol, polyethylene glycol and diethylene glycol; the organic acid is at least one selected from citric acid, malic acid and tartaric acid.

8. The method for hydrotreating poor quality catalytic diesel oil according to claim 7, wherein the alcohol is polyethylene glycol or diethylene glycol, and the organic acid is citric acid.