CN113430004A

CN113430004A - Inferior catalytic diesel oil hydrotreating method

Info

Publication number: CN113430004A
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: 2021-09-24
Anticipated expiration: 2040-03-23
Also published as: CN113430004B

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 hydrogenation treatment is a process of contacting diesel oil and hydrogen with a catalyst under a certain temperature and pressure condition to remove impurities and saturate aromatic hydrocarbon. 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. Many patents disclose the use of various organic compounds, such as oxygen-containing organic compound polyols or etherates thereof (WO96/41848, US3954673, US 4012340).

Patent JP 04166231 discloses a method for preparing a hydrotreating catalyst by impregnating a porous support with a metal solution, drying the impregnated support at a temperature of not higher than 200 ℃, and subjecting the dried support to a drying step after contacting the support with a polyol. EP 0601722 discloses a method for preparing a catalyst, characterized in that a porous alumina carrier is impregnated with an aqueous metal solution containing a glycol, and the impregnated carrier is subjected to a primary drying step without being subjected to a calcination process to prepare a finished catalyst.

US 6218333 discloses a method of 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 different size and shape particles together in a 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 only one or two of the three types of catalysts in the same quantity and under the same operation conditions, the method can improve the activity of the hydrotreatment process, and simultaneously deeply remove heterocyclic compounds such as sulfur, nitrogen and the like in the poor-quality catalytic diesel oil, thereby realizing 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 lubricating oil base 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 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 the poor-quality diesel oil is contacted with a first catalyst, wherein the first catalyst is a type I catalyst prepared after roasting, 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 of step a) with a second catalyst, wherein the second catalyst is a type II catalyst without roasting process, 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 step ii, impregnating the porous carrier with a 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 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 is from 20% to 30% by weight based on the total weight of the catalyst, the amount of the metal selected from group VIII is from 3% to 5% by weight based on the total weight of the catalyst of an oxide of the metal selected from group VIII, and the amount of phosphorus is in the range of from 3% to 5% by weight based on the total weight of the catalyst of P2O 5.

In the present invention, step a) is carried out in a volume V₁In a first zone containing a first catalyst, step b) being carried out in an occupation volume V₂In a second zone containing a second catalyst, step c) being carried out in an occupation volume V₃In a third zone containing a third catalyst. Volume distribution ratio V₁/V₂/V₃Preferably, the concentration is 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.

Catalysts A, B, C and D were first prepared by the following method:

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. A NiMoP solution was prepared by heat-dissolving molybdenum trioxide (24g), basic nickel carbonate (8g), and 85% phosphoric acid (8g) in a hot phosphoric acid 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; a NiMoP solution was prepared by heat-dissolving molybdenum trioxide (24g), basic nickel carbonate (8g), and 85% phosphoric acid (8g) in a hot phosphoric acid solution. And (3) soaking the catalyst precursor in a NiMoP-CA (citric acid) -PEG (polyethylene glycol molecular weight of 2000) mixed solution, curing at room temperature for 6 hours, and drying at 100-260 ℃ for 6 hours to obtain a 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; a CoMoP solution was prepared by heat-dissolving molybdenum trioxide (24g), cobalt hydroxide (2.3g), and 85% phosphoric acid in a hot phosphoric acid solution. Adding the CoMoP mixed solution into the carrier, curing the extrudate at room temperature for 6 hours after impregnation, 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 (24g), basic nickel carbonate (5g), and 85% phosphoric acid in a hot phosphoric acid solution. And (3) soaking the catalyst precursor in a NiMoP-CA-PEG (polyethylene glycol molecular weight of 2000) mixed solution, 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; a NiMoP solution was prepared by heat-dissolving molybdenum trioxide (24g) and basic nickel carbonate (5g) in 85% phosphoric acid in a hot phosphoric acid 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.

A CoMoP solution was prepared by heat-dissolving molybdenum trioxide (24g), cobalt hydroxide (2.3g), and 85% phosphoric acid in a hot phosphoric acid solution. And (3) soaking the catalyst precursor in a mixed solution of CoMoP-CA-PEG (polyethylene glycol molecular weight of 2000), curing at room temperature for 6 hours, and drying at 100-260 ℃ for 6 hours to obtain an I/II type NiMo/CoMo catalyst D.

Various grading combinations of catalysts A, B, C and D in the hydrotreatment of poor quality catalytic diesel were evaluated:

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

Simulated distillation:

IP：160℃

5％：210℃

10％：229℃

50％：290℃

70％：315℃

90％：343℃

the tests were conducted in an isothermal pilot reactor with a fixed flush bed, comprising three catalytic zones, for evaluation of 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) contained 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 10ppm nitrogen content for various combinations of gradations of catalyst 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 reactor outlet 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:

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

3. The method for hydrotreating poor quality catalytic diesel oil according to claim 1, characterized in that the metal of group VIB is selected from molybdenum and/or tungsten, and the metal of group VIII is selected from cobalt and/or nickel.

4. The method for hydrotreating poor quality catalytic diesel oil according to claim 1, characterized in that the active metals of the first catalyst are Ni and Mo-P; the active metals of the second catalyst are Co and Mo.

5. The method for hydrotreating poor quality catalytic diesel oil according to claim 1, wherein in the first, second and third catalysts, the mass of the metal of group VIB is 20% -30% of the total mass of the catalysts, the mass of the metal of group VIII is 3% -5% of the total mass of the catalysts based on the mass of the oxides, and the phosphorus is P₂O₅Calculated by 3 to 5 percent of the total mass of the catalyst.

6. The method as claimed in any one of claims 1 to 5, wherein the nitrogen content in the lube base oil is 1000-2500 ppm.

7. The method for hydrotreating poor quality catalytic diesel oil according to claim 1, wherein the preparation method of the first catalyst comprises the following steps:

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

step ii: and (3) impregnating the porous carrier with a NiMoP solution containing Ni, Mo and P elements, curing, drying, and roasting at 400-600 ℃ for 2-4 hours to obtain the first catalyst.

8. The method for hydrotreating poor quality catalytic diesel oil according to claim 1, wherein the method for preparing the second catalyst comprises the following steps:

step ii: and (3) impregnating the porous carrier with a NiMoP metal solution containing an organic auxiliary agent, curing and drying the porous carrier without a roasting process to obtain a second catalyst.

9. The method for hydrotreating poor quality catalytic diesel oil according to claim 1, wherein the preparation method of the third catalyst comprises the following steps:

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

step ii: impregnating the porous carrier with a 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: and (3) dipping the catalyst intermediate obtained in the step (ii) by using a NiMoP metal solution containing an organic auxiliary agent, curing and drying the catalyst intermediate, and obtaining a third catalyst without a roasting process.

10. The method for hydrotreating poor quality catalytic diesel oil according to claim 1, wherein the roasting temperature is 450-550 ℃, preferably 450-500 ℃.

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

12. The method for hydrotreating poor quality catalytic diesel oil according to claim 11, wherein the alcohol is at least one selected from the group consisting of ethylene glycol, propylene glycol, butylene glycol, polyethylene glycol, and diethylene glycol; the organic acid is at least one of citric acid, malic acid and tartaric acid.

13. The method for hydrotreating poor quality catalytic diesel oil according to claim 12, wherein the alcohol is polyethylene glycol or diethylene glycol, and the organic acid is citric acid.

14. The method for hydrotreating poor quality catalytic diesel oil according to claim 1,

said step (1) being carried out in a volume occupied by V₁In a first zone containing a first catalyst;

said step (2) is carried out in an occupied volume V₂Is composed ofIn a second zone of a second catalyst;

said step (3) is carried out in an occupied volume V₃In a third zone containing a third catalyst;

wherein the occupied volume V₁/V₂/V₃The distribution ratio of (A) is 10-30%/40-80%/10-30%.