CN114437818A

CN114437818A - Heavy aromatic oil processing method

Info

Publication number: CN114437818A
Application number: CN202011199960.7A
Authority: CN
Inventors: 李水荣; 徐保岳; 楼巧琳
Original assignee: Ningbo Zhongjin Petrochemical Co ltd
Current assignee: Ningbo Zhongjin Petrochemical Co ltd
Priority date: 2020-10-30
Filing date: 2020-10-30
Publication date: 2022-05-06
Anticipated expiration: 2040-10-30
Also published as: CN114437818B

Abstract

The invention relates to the field of petrochemicals, and discloses a heavy aromatic oil processing method which comprises the steps of distilling heavy aromatic oil to be divided into light fraction and heavy fraction, extracting the heavy fraction, part of BTX triphenyl and light toluene fraction to obtain an aromatic-poor component and an aromatic-rich component, distilling the aromatic-rich component to separate the light toluene fraction and the heavy toluene fraction, feeding the heavy toluene fraction and the light fraction into a hydrofining reactor, feeding a hydrogenation product and the aromatic-poor component into a hydrocracking reactor for further hydrocracking reaction, and distilling a cracking product to obtain C1-C4, BTX triphenyl, a small amount of diesel oil products and unconverted oil. The method can convert the cheap inferior heavy aromatic oil into liquefied gas, triphenyl and diesel oil products with high added values, and obviously improves the yield of the triphenyl and the comprehensive economy of a reforming device.

Description

Heavy aromatic oil processing method

Technical Field

The invention relates to the field of petrochemistry, in particular to a heavy aromatic oil processing method.

Background

The heavy aromatic oil is mainly from catalytic reforming and ethylene cracking devices. Reforming of C₉ ⁺Heavy aromatics account for about 15-20% of the processing capacity of a reforming device, the domestic reforming processing capacity is over 1 hundred million tons/year, and the reforming C₉ ⁺The productivity of heavy aromatics is 1500-2000 ten thousand tons/year. Cleavage C₉ ⁺The heavy aromatics account for 10-20% of the capacity of the ethylene cracking device, the capacity of the domestic ethylene cracking device exceeds 2000 ten thousand tons/year, and the cracking C is₉ ⁺The productivity of heavy aromatics is 100-200 ten thousand tons/year. In future, along with the construction of aromatic hydrocarbon combination devices and large-scale ethylene devices in China and the capacity expansion transformation of the existing devices, the byproduct C₉ ⁺More and more heavy aromatic oil is available; for a long time, heavy aromatic oil resources are not fully utilized, and a small amount of heavy aromatic oil resources are used as a solvent and C is extracted₉、C₁₀Besides the monomer aromatic hydrocarbon, the monomer aromatic hydrocarbon is basically mixed into the fuel and burnt. Followed byThe environmental protection regulations in China are increasingly perfected, and blending and burning-out are limited. Therefore, how to effectively utilize the heavy aromatic oil resources and convert the heavy aromatic oil resources into BTX (benzene, toluene and xylene) has become one of the important subjects in the technical field of aromatic hydrocarbon at home and abroad.

The greatest advantage of heavy aromatics technology over other utilization routes is the ability to produce important basic organic feedstocks such as BTX. In recent years, transalkylation catalysts and processes have been developed by various companies such as UOP, ExxonMobil, and chinese petrochemistry, and among them, the tapray technology of UOP, Toray TAC9 technology of UOP, TransPlus technology of ExxonMobil, HAL technology of the institute of petrochemical engineering, and HAT-plus technology of the institute of petrochemical engineering. The molecular sieves currently used for hydrodealkylation of heavy aromatics are mainly ZSM-5, beta, mordenite and the like. The TransPlus process of ExxonMobil adopts a beta molecular sieve catalyst modified by double-bed precious metal, can treat heavy aromatic oil raw materials with high concentration, and has the problems of high catalyst cost, poor activity stability and the like. The patent publication CN1117404A discloses a bifunctional catalyst for HAL technology, which can process heavy aromatic oil under mild process conditions, wherein the catalyst has 60% of ZSM-5 molecular sieve content, 25% of silica-alumina ratio, 40% of alumina as a carrier, and platinum and rhenium as active metals, the conversion per pass is 35-50%, and the total BTX yield is only about 63%. The catalyst used in the HAT process adopts a non-noble metal modified macroporous nano beta molecular sieve, so that the cost of the catalyst is reduced, the capability of the catalyst for treating heavy aromatic oil is further improved, the average conversion rate is higher than 55%, and the total BTX is more than 75% (Daiheiliang, Adiance technology, China petrochemical Press, 2014.12, P260-P268), but the total BTX yield is also low. The particle size of the macroporous nano beta molecular sieve is about 50-100 nm, the particle size is slightly large, and 2 or more than 2 aromatic hydrocarbons can reach an acid center through a pore channel due to the overlarge pore channel, so that the polymerization is caused to form coke, and the BTX yield and the service life of the catalyst are influenced.

At present, the heavy aromatics are mostly used for producing triphenyl products (Liu Yi, etc., the 'heavy aromatics weight conversion technology and shallow prospect analysis', the technical application and research, 2017.06, P40-P41) by adopting the technical route, and the distillation/extraction/hydrogenation combined technical route adopted by the method is not reported.

CN110465327A, CN108940354A and CN110180581A all disclose a heavy aromatics light catalyst and a preparation method thereof, wherein the active components of the former two are noble metal element oxides, the active component of the latter is noble and non-noble metal element oxides, and the three components contain molecular sieves, which belong to the category of hydrocracking catalysts and are different from the hydrofining catalyst provided by the invention.

Disclosure of Invention

In order to solve the technical problem, the invention provides a heavy aromatic oil processing method.

Firstly, the processing method of heavy aromatic oil can convert the cheap and poor heavy aromatic oil into liquefied gas, triphenyl and diesel oil products with high added values, and obviously improves the yield of triphenyl and the comprehensive economy of a reforming device.

Secondly, the hydrofining catalyst of the invention has the advantages of large specific surface area and good activity.

The specific technical scheme of the invention is as follows:

in a first aspect, the present invention provides a method for processing heavy aromatic oil, comprising the following steps:

A) the heavy aromatic oil is separated into a light fraction and a heavy fraction by distillation.

B) Extracting the heavy fraction to obtain an aromatic-poor component and an aromatic-rich component.

C) Distilling the aromatic-rich component to separate a light toluene fraction and a heavy toluene fraction; wherein the light toluene fraction is returned to step B) and extracted together with the heavy fraction.

D) And B) feeding the heavy toluene fraction and the light fraction obtained in the step A) into a hydrofining reactor filled with a hydrofining catalyst to remove S, N, O heteroatom compounds for reaction, and obtaining a hydrogenation product.

E) The hydrogenation product obtained in the step D) and the poor aromatic component obtained in the step B) enter a hydrocracking reactor together for hydrocracking reaction to obtain a cracking product.

F) Distilling the obtained cracked product to obtain C1-C4, BTX triphenyl, a small amount of diesel oil product and unconverted oil; wherein part of the BTX triphenyl is returned to the step B) to be extracted together with the heavy fraction; returning the unconverted oil to the step A) and co-distilling with the heavy aromatic oil.

The processing method of the invention has the following technical effects:

1) the heavy aromatic oil provided by the invention adopts a processing method of distillation/extraction/hydrogenation combined technology, the monocyclic aromatic hydrocarbon and the polycyclic aromatic hydrocarbon compound in the heavy aromatic oil are respectively processed, and the latter is pertinently purified and subjected to hydrogenation conversion, so that the low-cost and poor-quality heavy aromatic oil is converted into liquefied gas and triphenyl products with high added values, and the triphenyl yield and the comprehensive economy of a reforming device are obviously improved.

2) The heavy aromatic oil provided by the invention adopts a processing method of distillation/extraction/hydrogenation combined technology, the heavy aromatic oil is distilled and separated into light fraction (high content of monocyclic aromatic hydrocarbon) at a temperature of less than 200 ℃ and heavy fraction (high content of polycyclic aromatic hydrocarbon) at a temperature of more than 200 ℃, the two fractions adopt different processing methods, and a hydrofining catalyst is filled in a hydrocracking reactor, so that the aromatic-poor component and a hydrofining product entering the reactor are subjected to further aromatic hydrocarbon hydrogenation saturation and cracking reaction together, and the step of flowing the aromatic-poor component through the hydrofining reactor is omitted, thereby saving energy consumption and being beneficial to reducing production cost.

3) The method utilizes the light toluene fraction and part of BTX products in the heavy aromatic oil as the extraction solvent for purifying the aromatic compounds in the heavy aromatic oil, thereby avoiding the consumption of raw material solvents and effectively reducing the raw material cost in the industrial production process.

Preferably, in step A), the boiling point of the light fraction is < 200 ℃ and the boiling point of the heavy fraction is > 200 ℃.

Preferably, in the step B), the back-extracted BTX triphenyl accounts for 5-25% of the total amount of the BTX triphenyl obtained in the step F), the mass ratio of the total mass of the back-extracted BTX triphenyl and the back-extracted light toluene fraction to the heavy fraction is 2-3: 1, the extraction temperature is 20-40 ℃, and the extraction time is 2-10 h.

Preferably, in step C), the boiling point of the light toluene fraction is < 110 ℃ and the boiling point of the heavy toluene fraction is > 110 ℃.

Preferably, step E) comprises loading the hydrocracking reactor with the catalyst in a graded loading manner; wherein, the upper part of the hydrocracking reactor is filled with a hydrofining catalyst, and the lower part is filled with a hydrocracking catalyst; the volume ratio of the hydrofining catalyst to the hydrocracking catalyst is 1-2: 1.

Preferably, the reaction temperature of the hydrofining reactor is 200-230 ℃, the hydrogen partial pressure is 4.0-5.0MPa, the volume ratio of hydrogen to oil is 900-^-1. The reaction temperature of the hydrocracking reactor is 360-380 ℃, the hydrogen partial pressure is 7.0-9.0MPa, the volume ratio of hydrogen to oil is 900-^-1。

Preferably, the hydrofining catalyst has a pore volume of 0.9-1.3 mL/g and a specific surface area of 150-350 m²(g) the crushing strength is 300N cm^-1The above; the catalyst comprises 15-25 wt% of metal oxide and 60-85 wt% of carrier;

the metal oxide is an oxide of at least one metal of molybdenum, tungsten, cobalt and nickel;

the carrier is mainly formed by mixing, extruding, molding, drying and roasting natural sponge powder and aluminum hydroxide dry glue powder.

Preferably, the metal oxide is molybdenum trioxide and/or tungsten trioxide, and accounts for 8-19 wt% of the total mass of the hydrofining catalyst; or the metal oxide is nickel oxide and/or cobalt oxide and accounts for 4-10 wt% of the total mass of the hydrofining catalyst.

Preferably, the amount of the natural sponge is 1.0-3.0 wt% of the total mass of the carrier.

Preferably, the pore volume of the aluminum hydroxide dry glue powder is 0.8-1.2 ml/g, and the specific surface area is 250-450 m²And the aluminum hydroxide dry glue powder accounts for 60-80% of the dry basis of the weight of the aluminum oxide.

Preferably, the amount of the natural sponge is 1.5-2.5 wt% of the total mass of the carrier.

Preferably, the hydrofining catalyst further comprises a peptizing agent and/or a binder; the binder comprises a small pore alumina and an inorganic and/or organic acid.

Preferably, the preparation method of the hydrofining catalyst comprises the following steps:

1) drying and crushing natural sponge to obtain natural sponge powder;

2) uniformly mixing aluminum hydroxide dry glue powder and the natural sponge powder, adding an extrusion aid, extruding, molding, drying and roasting to obtain a carrier;

3) adding a nonionic surfactant into a precursor aqueous solution of a metal oxide to form an impregnation solution, wherein the precursor is a water-soluble compound corresponding to a metal element; dipping the carrier obtained in the step 2) in the dipping solution, and then drying and roasting to obtain the hydrofining catalyst.

The natural sponge powder with small particle size is added into the catalyst carrier to be used as the pore-enlarging agent, and the natural sponge belongs to marine organisms, has strong water absorption, large specific surface area and antibacterial effect, is a renewable resource, particularly has obvious water absorption which is obviously different from other physical pore-enlarging agents such as carbon black, activated carbon and the like, so that the natural sponge powder is more fully mixed with the aluminum hydroxide dry glue powder and has stronger binding force in the mixing process with the aluminum hydroxide dry glue powder, and meanwhile, the natural sponge is carbonized into the black powder with obvious volume change at high temperature, so that the pore volume and the specific surface area of the carrier can be further increased, and the pore-enlarging effect of accommodating impurity compounds can be obtained; on the other hand, as the main component is protein, the self-degradation property is good in the process of burning and burying the subsequent inactivated catalyst, the environment can be well protected, the damage to soil and water quality is reduced, and the virtuous cycle recycle of natural resources is realized.

Preferably, in the step 1), the natural sponge is subjected to air-blast drying and crushing treatment; wherein the blast drying temperature is 40-55 ℃, and the blast drying time is 10-24 h; blowing air speed is 3-5 m/s; the granularity of the natural sponge powder obtained after crushing is 1000-2000 meshes.

Preferably, step 2) specifically comprises: uniformly mixing aluminum hydroxide dry glue powder and natural sponge powder at room temperature, adding an extrusion aid, extruding into strips, and then drying and roasting; wherein the drying temperature is 100-160 ℃; the roasting temperature is 400-650 ℃, and the roasting time is 1-15 h.

Preferably, in step 3): soaking the carrier in the soaking solution for 5-10 h; the drying temperature is 100-160 ℃, the roasting temperature is 400-650 ℃, and the roasting time is 1-15 h.

Preferably, in step 3): the water-soluble compound is a salt compound corresponding to a metal element, and the concentration of the metal in the water-soluble compound is 5-50 g/100 mL; the dosage of the nonionic surfactant is 2-10 wt% of the total mass of the carrier.

Preferably, the water-soluble compound is at least one of ammonium molybdate, ammonium metatungstate, nickel nitrate, basic nickel carbonate, cobalt nitrate and cobalt acetate.

Preferably, the nonionic surfactant is a fatty alcohol polyether.

Compared with the prior art, the invention has the following technical effects:

(1) the heavy aromatic oil processing method provided by the invention adopts the steps that firstly, monocyclic aromatic hydrocarbon and condensed-ring aromatic hydrocarbon are separated by distillation, the condensed-ring aromatic hydrocarbon adopts a light toluene component and a part of triphenyl products as extraction solvents, and the light toluene component and a part of triphenyl products are recycled as the extraction solvents, so that the consumption of solvent raw materials is effectively avoided, and the cost of the raw materials is greatly reduced; the obtained heavy toluene fraction and light fraction enter a hydrofining reactor together, firstly, S, N, O heteroatom compound removal reaction and polycyclic aromatic hydrocarbon partial hydrogenation saturation reaction are carried out, then the hydrogenation product enters a hydrocracking reactor together with the poor aromatic component, and further hydrocracking reaction for removing S, N, O heteroatom compounds, tetrahydronaphthalene compounds and other compounds is carried out, so that the expected monocyclic aromatic hydrocarbon product is obtained. The method adopts different treatment methods aiming at different fractions, and reduces the feeding proportion of the hydrofining reactor because of avoiding the poor aromatic components from entering the hydrofining reactor, thereby saving energy consumption, reducing production cost and being beneficial to improving the comprehensive economy of a production device.

(2) The heavy aromatic oil hydrorefining catalyst provided by the invention adopts natural sponge powder with small particle size, and the particle size is about 10 nm. The natural sponge belongs to marine organisms, the main components of the natural sponge are protein and mineral substances, and the natural sponge has excellent strong water absorption, large specific surface area and strong antibacterial property, and belongs to renewable resources. The combination of the natural sponge powder and the alumina carrier further increases the pore volume and the specific surface area of the alumina carrier, obtains the hole-enlarging effect of compounds capable of containing impurities and is beneficial to prolonging the service life of the catalyst. Meanwhile, the amount of the natural sponge added into the alumina carrier is small and is not more than 3.0 percent, so that the strength of the prepared catalyst cannot be damaged like other physical pore-expanding agents. More importantly, as the natural sponge is a renewable resource, the self degradability of the natural sponge is good in the subsequent incineration landfill treatment of the inactivated catalyst, the damage of pore-expanding agents such as other petroleum derivatives to soil, water quality and the like can be avoided, the earth environment where people rely on to live is better protected, the carbon emission is reduced, and the virtuous cycle recycling of natural resources is realized.

Detailed Description

The present invention will be further described with reference to the following examples.

General examples

A) the heavy aromatic oil is distilled to separate into light fraction with boiling point less than 200 deg.c and heavy fraction with boiling point greater than 200 deg.c.

B) And extracting the heavy fraction with the recycled BTX triphenyl and light toluene fraction to obtain an aromatic-poor component and an aromatic-rich component. Wherein the BTX triphenyl returning to the extraction accounts for 5-25% of the total amount of the BTX triphenyl obtained in the step F), the mass ratio of the total mass of the BTX triphenyl returning to the extraction and the light toluene fraction returning to the extraction to the heavy fraction is 2-3: 1, the extraction temperature is 20-40 ℃, and the extraction time is 2-10 h.

C) Distilling the aromatic-rich component to separate a light toluene fraction with a boiling point less than 110 ℃ and a heavy toluene fraction with a boiling point more than 110 ℃; wherein the light toluene fraction is returned to step B) and extracted together with the heavy fraction.

E) The hydrogenation product obtained in the step D) and the poor aromatic component obtained in the step B) enter a hydrocracking reactor together for hydrocracking reaction to obtain a cracking product. The reaction temperature of the hydrofining reactor is 200-230 ℃, the hydrogen partial pressure is 4.0-5.0MPa, the volume ratio of hydrogen to oil is 900-^-1. The reaction temperature of the hydrocracking reactor is 360-380 ℃, the hydrogen partial pressure is 7.0-9.0MPa, the volume ratio of hydrogen to oil is 900-^-1. Filling a catalyst in the hydrocracking reactor in a grading filling mode; wherein, the upper part of the hydrocracking reactor is filled with a hydrofining catalyst, and the lower part is filled with a hydrocracking catalyst; the volume ratio of the hydrofining catalyst to the hydrocracking catalyst is 1-2: 1.

The hydrorefining catalyst has a pore volume of 0.9-1.3 mL/g and a specific surface area of 150-350 m²(g) the crushing strength is 300N cm^-1The above; the catalyst comprises 15-25 wt% of metal oxide and 60-85 wt% of carrier; the metal oxide is an oxide of at least one metal of molybdenum, tungsten, cobalt and nickel; the carrier is mainly formed by mixing, extruding, molding, drying and roasting natural sponge powder and aluminum hydroxide dry glue powder.

Preferably, the amount of the natural sponge is 1.0-3.0 wt% of the total mass of the carrier. More preferably, the amount of the natural sponge is 1.5-2.5 wt% of the total mass of the carrier.

Preferably, the pore volume of the aluminum hydroxide dry glue powder is 0.8-1.2 ml/g, and the specific surface area is 250-450 m²The aluminum hydroxide dry glue powder accounts for 60-80% of the dry basis of the weight of the aluminum oxide.

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

1) drying and crushing natural sponge to obtain natural sponge powder; wherein the blast drying temperature is 40-55 ℃, and the blast drying time is 10-24 h; blowing air speed is 3-5 m/s; the granularity of the natural sponge powder obtained after crushing is 1000-2000 meshes.

2) Uniformly mixing aluminum hydroxide dry glue powder and natural sponge powder at room temperature, adding an extrusion aid, extruding into strips, and then drying and roasting; wherein the drying temperature is 100-160 ℃; and roasting at the temperature of 400-650 ℃ for 1-15 h to obtain the carrier.

3) Adding a nonionic surfactant into a precursor aqueous solution of a metal oxide to form an impregnation solution, wherein the precursor is a water-soluble compound corresponding to a metal element; dipping the carrier obtained in the step 2) in the dipping solution for 5-10 h, and then drying at 100-160 ℃ and roasting at 400-650 ℃ for 1-15 h to obtain the hydrofining catalyst. The water-soluble compound is a salt compound corresponding to a metal element, and the concentration of the metal in the water-soluble compound is 5-50 g/100 mL; the dosage of the nonionic surfactant is 2-10 wt% of the total mass of the carrier.

Preferably, the water-soluble compound is at least one of ammonium molybdate, ammonium metatungstate, nickel nitrate, basic nickel carbonate, cobalt nitrate and cobalt acetate. The nonionic surfactant is fatty alcohol polyether.

The technical solution of the present invention is further explained below with reference to several examples.

The following examples all use active goldBelongs to the dipping solution. The method of preparing the impregnation solution is illustrated by taking the active metals molybdenum and cobalt as examples: taking a certain amount of deionized water, adding ammonium molybdate (or ammonium metatungstate) and cobalt nitrate (or cobalt acetate, basic nickel carbonate and nickel nitrate) crystals, standing after all the crystals are dissolved, and filtering to obtain a metal impregnation solution, wherein MoO₃Or WO₃The content of (b) is 10.0-50.0 g/100ml, and the content of CoO or NiO is 5.0-15.0 g/100 ml. The preparation of metal impregnation solutions is well known in the art and reference is made to the relevant literature.

The natural sponges used in the following examples were commercially available natural sponges, and the impurity content was 2.0%.

Example 1

Firstly, 5.6g of natural sponge is dried by air blowing, the air speed of an air blower is 4 m/s, the drying temperature is 45 ℃, the air blowing drying time is 17h, and then the natural sponge powder with the granularity of 2000 meshes is obtained by crushing; mixing the natural sponge powder with 200g of aluminum hydroxide dry glue powder (dry basis is 80%) at room temperature, adding extrusion aid such as citric acid during mixing process, and using amount to meet carrier forming standard; after being mixed evenly, the mixture is dried and roasted to obtain the carrier. Wherein the drying temperature is 160 ℃, and the drying time is 5 hours; the roasting temperature is 400 ℃, and the roasting time is 8 hours.

Adding dodecyl alcohol polyether into 100mL of the prepared tungsten-cobalt impregnation solution with the concentration of 32.0g of metal (calculated by oxide, the tungsten/cobalt ratio is 3: 1)/100mL of the solution, adding the dodecyl alcohol polyether according to 2-10% of the total mass of the carrier to prepare an aqueous solution, impregnating 100g of the carrier at the impregnation temperature of 20 ℃ for 5 hours, drying at the temperature of 160 ℃ for 7 hours, cutting into 3-6 mm lengths, roasting at the roasting temperature of 400 ℃ for 8 hours to obtain a hydrofining catalyst, wherein the catalyst is named as C1, and the composition and the physicochemical properties of the hydrofining catalyst are shown in Table 2.

Example 2

Firstly, blowing 5.0g of natural sponge for drying at the air speed of 5 m/s and the drying temperature of 50 ℃ for 24h, and crushing to obtain natural sponge powder with the granularity of 1000 meshes; mixing the natural sponge powder with 200g of aluminum hydroxide dry glue powder (dry basis is 60%) at room temperature, adding extrusion aid such as citric acid during mixing process, and using amount to meet carrier forming standard; after being mixed evenly, the mixture is dried and roasted to obtain the carrier. Wherein the drying temperature is 100 ℃, and the drying time is 7 hours; the roasting temperature is 650 ℃ and the roasting time is 1 hour.

Adding dodecyl alcohol polyether into 100mL of the prepared molybdenum-cobalt impregnation solution with the concentration of 30.0g of metal (calculated by oxide, the ratio of molybdenum to cobalt is 3: 1)/100mL of the solution, adding the dodecyl alcohol polyether according to 2-10% of the total mass of the carrier to prepare an aqueous solution, impregnating 100g of the carrier at the impregnation temperature of 25 ℃ for 7 hours, drying at the impregnation temperature of 100 ℃ for 2 hours, cutting into 3-6 mm lengths, roasting at the roasting temperature of 500 ℃ for 10 hours to obtain a hydrofining catalyst, wherein the catalyst is named as C2, and the composition and the physicochemical properties of the hydrofining catalyst are shown in Table 2.

Example 3

Firstly, blowing 5.2g of natural sponge for drying at 40 ℃ for 10h at the air speed of 3 m/s by an air blower, and crushing to obtain natural sponge powder with the granularity of 1400 meshes; mixing the natural sponge powder with 200g of aluminum hydroxide dry glue powder (dry basis is 70%) at room temperature, adding extrusion aid such as citric acid during mixing process, and using amount to meet carrier forming standard; after being mixed evenly, the mixture is dried and roasted to obtain the carrier. Wherein the drying temperature is 140 ℃, and the drying time is 3 hours; the roasting temperature is 550 ℃, and the roasting time is 6 hours.

Adding dodecyl alcohol polyether into 100mL of the prepared tungsten-nickel impregnation solution with the concentration of 28.0g of metal (calculated by oxide, the tungsten/nickel ratio is 3: 1)/100mL of the solution, adding the dodecyl alcohol polyether according to 2-10% of the total mass of the carrier to prepare an aqueous solution, impregnating 100g of the carrier at the impregnation temperature of 25 ℃ for 10 hours, drying at the impregnation temperature of 140 ℃ for 4 hours, cutting into 3-6 mm lengths, roasting at the roasting temperature of 550 ℃ for 15 hours to obtain a hydrofining catalyst, wherein the catalyst is named as C3, and the composition and the physicochemical properties of the hydrofining catalyst are shown in Table 2.

Example 4

Firstly, blowing 5.4g of natural sponge for drying at the air speed of 3.5 m/s and the drying temperature of 55 ℃ for 19h, and crushing to obtain natural sponge powder with the granularity of 1200 meshes; mixing the natural sponge powder with 210g of aluminum hydroxide dry glue powder (dry basis is 80%) at room temperature, adding extrusion aid such as citric acid during mixing process, and using amount to meet carrier forming standard; after being mixed evenly, the mixture is dried and roasted to obtain the carrier. Wherein the drying temperature is 120 ℃, and the drying time is 4 hours; the roasting temperature is 500 ℃, and the roasting time is 15 hours.

Adding dodecyl alcohol polyether into 100mL of the prepared molybdenum-nickel impregnation solution with the concentration of 26.0g of metal (calculated by oxide, the ratio of molybdenum to nickel is 3: 1)/100mL of the solution, adding the dodecyl alcohol polyether according to 2-10% of the total mass of the carrier to prepare an aqueous solution, impregnating 100g of the carrier at the impregnation temperature of 20 ℃ for 8 hours, drying at the temperature of 120 ℃ for 6 hours, cutting into 3-6 mm lengths, roasting at the roasting temperature of 650 ℃ for 1 hour to obtain the hydrofining catalyst, wherein the catalyst is named as C4, and the composition and the physicochemical properties of the hydrofining catalyst are shown in Table 2.

Comparative example 1

In this comparative example, natural sponge was not used, and a general physical pore-expanding agent such as carbon black was used, and the other steps were the same as those in the preparation of the catalyst C3 in example 3, and the obtained catalyst was numbered DC1, and its composition and physical and chemical properties are shown in table 2.

The compositions and physical and chemical properties of the catalysts C1-C4 obtained in examples 1-4 and the catalyst DC1 obtained in the control example were measured and are shown in Table 2.

TABLE 2 compositions and physico-chemical properties of catalysts C1-C4 obtained in examples 1-4 and of catalyst DC1 obtained in comparative example

Number of	C1	C2	C3	C4	DC1
						Aluminum oxide,% of	73.3	73.9	75.4	76.9	75.4
Natural sponge%	2.5	3.0	2.7	2.5	2.7 (carbon black)
						WO₃(or MoO)₃)，％	18.1	17.3	16.4	15.5	16.4
NiO (or CoO),%	6.1	5.8	5.5	5.1	5.5
						Pore volume, ml/g	1.2	1.0	1.1	1.2	1.6
Specific surface area, m²/g	290	295	292	288	123
						Crush strength N/cm	320	318	320	321	159

Cracking C was used as the raw oil for evaluating the activity of the C1-C4 catalysts obtained in examples 1-4 of the present invention and the DC1 catalyst obtained in the comparative example₉ ⁺Heavy aromatics feed oil, this feed oil being based on C₉And above aromatic hydrocarbons, generally having the composition C₈ ^-Aromatic hydrocarbon, C₉Aromatic hydrocarbon, C₁₀ ⁺Aromatic hydrocarbon and naphthalene and derivatives, total aromatic hydrocarbon about 75.9%, colloid 4.7mg/100g, diene 5.8gI₂/100g。

Firstly, the hydrorefining process is carried out, the hydrorefining catalyst C3 in the example and the catalyst DC1 in the comparative example are selected, and the hydrorefining process conditions are as follows: volume space velocity of 0.6h^-1And obtaining the hydrofined product oil under the conditions that the hydrogen partial pressure of the system reaction pressure is 5.0MPa, the reaction temperature is 200-230 ℃ and the hydrogen-oil ratio is 1000. Hydrorefining oil composition corresponding to C3: total aromatics of about 78.5%, where C₈ ^-Aromatic hydrocarbon 28.2%, C₉Arene 34.8 percent, C₁₀ ⁺Aromatic hydrocarbons11.3 percent of naphthalene and derivatives, 4.2 percent of naphthalene and derivatives, and the dry point is about 215 ℃, and the serial number of the raw oil is CHO; hydrorefining oil composition corresponding to DC 1: total aromatics of about 73.8%, where C₈ ^-Aromatic hydrocarbons 15.1%, C₉Aromatic hydrocarbon 32.0%, C₁₀ ⁺Aromatic hydrocarbon 21.5%, naphthalene and derivative 5.2%, dry point about 209 ℃, the serial number of the raw oil is DCHO; examples 1-4 the hydrofinishing reactor of example 1 was filled with hydrofinishing catalyst C1, which was conventionally used in the industry, and the reactor was fitted with a 20% commercially available FZC series hydrogenation protection catalyst from the petrochemical industry. The upper part of the hydrocracking reactor is filled with a C3 hydrofining catalyst, and the lower part is filled with a commercially available petroleum-based distillate oil hydrocracking catalyst and a hydrocracking catalyst, wherein the catalyst mainly has the physical and chemical properties: the active metal is tungsten and nickel; pore volume of 0.3ml/g and specific surface area of 220m²(g), cylindrical strip shape, particle diameter of 1.6mm, and compressive strength of 182N/cm. The volume ratio of the two is 1: 1. The small-sized evaluation device of the catalyst adopts a fixed bed hydrogenation catalyst grading mode and a vulcanization start-up step which are well known by a person skilled in the art, a product sample with initial activity is taken when the device is operated for 50 hours after vulcanization is finished, the product sample is taken again after the device is continuously operated for 2000 hours, the product is sampled twice, and performance evaluation result data of the product is listed in a table 3.

TABLE 3 evaluation results of performances of the hydrorefining catalyst C3 obtained in example 3 and the catalyst DC1 obtained in the comparative example

As can be seen from tables 2 and 3, the hydrorefining catalyst obtained by the present invention has good activity and BTX yield significantly higher than that of the hydrorefining catalyst without natural sponge compared to the conventional heavy aromatic oil refining catalyst.

Example 5

The method for processing heavy aromatic oil and the catalyst thereof comprise the process of distilling and extracting heavy aromatic oil, and then obtaining a triphenyl product through two-stage hydrogenation. Heavy aromatics are distilled and divided into light fraction at the temperature of less than 200 ℃ and heavy fraction at the temperature of more than 200 ℃, the heavy fraction is extracted with part of BTX triphenyl and light toluene fraction which are recycled to obtain aromatic-poor component and aromatic-rich component 7, the light toluene fraction at the temperature of less than 110 ℃ and the heavy toluene fraction at the temperature of more than 110 ℃ which can be recycled are separated by distillation, the heavy toluene fraction and the light fraction enter a hydrofining reactor to carry out a hydrogenation refining reaction to remove S, N, O heteroatom compounds and a partial hydrogenation saturation reaction of condensed ring aromatics, the hydrogenation product enters a hydrocracking reactor together with the aromatic-poor component to carry out a hydrocracking reaction for further removing S, N, O heteroatom compounds, tetrahydronaphthalene compounds and the like to obtain the expected monocyclic aromatics, and gas C1-C4 products, BTX triphenyl products, a small amount of diesel oil products and unconverted oil are obtained by distillation and recycled to be fresh feed and mixed with the heavy aromatics, the reaction was restarted.

In this example, a hydrofining reactor was filled with the hydrofining catalyst C1 obtained in example 1, and the top of the reactor was matched with a 20% commercially available FZC series hydrofining catalyst of the petrochemical industry, according to the industry's convention. The hydrorefining catalyst C1 obtained in example 1 was filled in the middle-upper part of the hydrocracking reactor, and the hydrocracking catalyst was filled in the lower part thereof, and the catalyst had the following main physicochemical properties: the active metal is tungsten and nickel; pore volume of 0.3ml/g and specific surface area of 220m²(iv) g, cylindrical bar shape, particle diameter of 1.6mm, and compressive strength of 182N/cm. The catalyst volume ratio of the two parts is 2: 1. In the process, part of the triphenyl product and the light toluene fraction which account for 25 percent of the BTX product are used as extraction solvents of the heavy fraction to extract to obtain an aromatic-poor component and an aromatic-rich component, the extraction temperature is 20 ℃, the mass ratio of the extraction temperature to the extraction temperature is 2:1, and the extraction time is 10 hours.

Example 6

The procedure is as in example 5 except that the hydrocracking reactor is filled with catalyst and part of the extraction of the triphenyl product is carried out. In this example, the hydrorefining catalyst C2 obtained in example 2 was filled in the upper middle part of the hydrocracking reactor, and the hydrocracking catalyst was filled in the lower part thereof, the catalyst volume ratio of the two parts being 1: 1; in the extraction process, a part of triphenyl product and light toluene fraction which account for 5 percent of the triphenyl product BTX are used as extraction solvents of heavy fraction to extract to obtain poor aromatic components and rich aromatic components, the extraction temperature is 40 ℃, the mass ratio of the poor aromatic components to the heavy fraction BTX is 3: 1, and the extraction time is 2 hours.

Through the examples 1 to 6, it can be found that the heavy aromatic oil processing method and the hydrorefining catalyst thereof obtained by the technical scheme of the invention have the advantages of large specific surface area and good activity, are suitable for hydrotreating the heavy aromatic oil, the ethylene cracking heavy aromatic oil, and the mixed heavy aromatic oil by-product in the process of producing benzene compounds by hydrogenation of the heavy aromatic oil by using the heavy aromatic oil as a raw material, have stable and good activity, allow the polycyclic aromatic hydrocarbon to be hydrogenated and saturated, and cracked into benzene aromatic hydrocarbons, and remarkably improve the BTX yield.

In addition, the inventors of the present invention have also conducted experiments using other raw materials and conditions listed in the present specification by referring to the modes of examples 1 to 6, and have similarly obtained a hydrorefining catalyst having good activity, large specific surface area, large strength, and good activity stability, and also obtained a high yield of triphenyl.

The raw materials and equipment used in the invention are common raw materials and equipment in the field if not specified; the methods used in the present invention are conventional in the art unless otherwise specified.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, alterations and equivalents of the above embodiments according to the technical spirit of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A method for processing heavy aromatic oil is characterized in that: the method comprises the following steps:

A) distilling the heavy aromatic oil to separate into light fraction and heavy fraction;

B) extracting the heavy fraction to obtain an aromatic-poor component and an aromatic-rich component;

C) distilling the aromatic-rich component to separate a light toluene fraction and a heavy toluene fraction; wherein the light toluene fraction is returned to step B) and extracted together with the heavy fraction;

D) the heavy toluene fraction and the light fraction obtained in the step A) enter a hydrofining reactor filled with hydrofining catalyst together to remove S, N, O heteroatom compounds for reaction, and then a hydrogenation product is obtained;

E) the hydrogenation product obtained in the step D) and the poor aromatic component obtained in the step B) enter a hydrocracking reactor together for hydrocracking reaction to obtain a cracked product;

2. The method of claim 1, wherein:

in the step A), the boiling point of the light fraction is less than 200 ℃, and the boiling point of the heavy fraction is more than 200 ℃; and/or

In the step B), the back-extracted BTX triphenyl accounts for 5-25% of the total amount of the BTX triphenyl obtained in the step F), and the mass ratio of the total mass of the back-extracted BTX triphenyl and the back-extracted light toluene fraction to the heavy fraction is 2-3: 1, extracting at the temperature of 20-40 ℃ for 2-10 h; and/or

In the step C), the boiling point of the light toluene fraction is less than 110 ℃, and the boiling point of the heavy toluene fraction is more than 110 ℃; and/or

In the step E), a catalyst is filled in the hydrocracking reactor in a grading filling mode; wherein, the upper part of the hydrocracking reactor is filled with a hydrofining catalyst, and the lower part is filled with a hydrocracking catalyst; the volume ratio of the hydrofining catalyst to the hydrocracking catalyst is 1-2: 1.

3. The method of claim 1, wherein:

the reaction temperature of the hydrofining reactor is 200-230 ℃, the hydrogen partial pressure is 4.0-5.0MPa, the hydrogen-oil volume ratio is 900-^-1(ii) a And/or

The reaction temperature of the hydrocracking reactor is 360-380 ℃, the hydrogen partial pressure is 7.0-9.0MPa, the hydrogen-oil volume ratio is 900-^-1。

4. The method of claim 1, wherein: the hydrorefining catalyst has a pore volume of 0.9-1.3 mL/g and a specific surface area of 150-350 m²(g) the crushing strength is 300N cm^-1The above; the catalyst comprises 15-25 wt% of metal oxide and 60-85 wt% of carrier;

5. The method of claim 4, wherein:

the metal oxide is molybdenum trioxide and/or tungsten trioxide and accounts for 8-19 wt% of the total mass of the hydrofining catalyst; or

The metal oxide is nickel oxide and/or cobalt oxide and accounts for 4-10 wt% of the total mass of the hydrofining catalyst; and/or

The dosage of the natural sponge is 1.0-3.0 wt% of the total mass of the carrier; and/or

The pore volume of the aluminum hydroxide dry glue powder is 0.8-1.2 ml/g, and the specific surface area is 250-450 m²And the aluminum hydroxide dry glue powder accounts for 60-80% of the dry basis of the weight of the aluminum oxide.

6. The method of claim 4, wherein:

the dosage of the natural sponge is 1.5-2.5 wt% of the total mass of the carrier.

7. The method of claim 4, wherein: the hydrofining catalyst also comprises a peptizing agent and/or a binding agent; the binder comprises a small pore alumina and an inorganic and/or organic acid.

8. The method of claim 4, wherein: the preparation method of the hydrofining catalyst comprises the following steps:

1) drying and crushing natural sponge to obtain natural sponge powder;

3) adding a nonionic surfactant into a precursor aqueous solution of a metal oxide to form an impregnation solution, wherein the precursor is a water-soluble compound corresponding to a metal element; dipping the carrier obtained in the step 2) into the dipping solution, and then drying and roasting to obtain the hydrofining catalyst.

9. The method of claim 8, wherein:

in the step 1), the natural sponge is subjected to forced air drying and crushing treatment; wherein the blast drying temperature is 40-55 ℃, and the blast drying time is 10-24 h; blowing air speed is 3-5 m/s; the granularity of the natural sponge powder obtained after crushing is 1000-2000 meshes; and/or

The step 2) specifically comprises the following steps: uniformly mixing aluminum hydroxide dry glue powder and natural sponge powder at room temperature, adding an extrusion aid, extruding into strips, and then drying and roasting; wherein the drying temperature is 100-160 ℃; the roasting temperature is 400-650 ℃, and the roasting time is 1-15 h; and/or

In step 3): soaking the carrier in the soaking solution for 5-10 h; the drying temperature is 100-160 ℃, the roasting temperature is 400-650 ℃, and the roasting time is 1-15 h; and/or

In step 3): the water-soluble compound is a salt compound corresponding to a metal element, and the concentration of the metal in the water-soluble compound is 5-50 g/100 mL; the dosage of the nonionic surfactant is 2-10 wt% of the total mass of the carrier.

10. The method of claim 9, wherein:

the water-soluble compound is at least one of ammonium molybdate, ammonium metatungstate, nickel nitrate, basic nickel carbonate, cobalt nitrate and cobalt acetate; and/or

The nonionic surfactant is fatty alcohol polyether.