阅读说明：本技术 一种通过复合溶剂分离催化裂化油浆中芳烃和饱和烃的方法 (Method for separating aromatic hydrocarbon and saturated hydrocarbon in catalytic cracking slurry oil through composite solvent ) 是由 张轩 杨涛 刘亚青 朱永红 王亦颿 黄传峰 杨天华 李伟 常方圆 杨程 焦有军 于 2021-09-14 设计创作，主要内容包括：一种通过复合溶剂分离催化裂化油浆中芳烃和饱和烃的方法,储罐的催化裂化油浆进入第一萃取塔,溶剂I进入第一萃取塔,沥青质组分从第一萃取塔底部流出,脱沥青油和溶剂I从第一萃取塔顶部流出,然后进入第一溶剂回收塔,得到脱沥青油,溶剂I回收至储罐循环使用；储罐的溶剂II和储罐的溶剂III泵入混合罐,得到复合溶剂,复合溶剂进入第二萃取塔,脱沥青油进入第二萃取塔,脱沥青油和复合溶剂在第二萃取塔内逆向接触,饱和烃组分从第二萃取塔顶部流出,芳烃组分和复合溶剂从第二萃取塔底部流出,进入第二溶剂回收塔,得到芳烃组分,复合溶剂回收至储罐循环使用。本发明以更加高效和环保的方式得到品质较好的芳烃组分和饱和烃组分。(A method for separating aromatic hydrocarbon and saturated hydrocarbon in catalytic cracking slurry oil through a composite solvent comprises the following steps that the catalytic cracking slurry oil of a storage tank enters a first extraction tower, a solvent I enters the first extraction tower, asphaltene components flow out from the bottom of the first extraction tower, deasphalted oil and the solvent I flow out from the top of the first extraction tower and then enter a first solvent recovery tower to obtain deasphalted oil, and the solvent I is recovered to the storage tank for recycling; and pumping the solvent II of the storage tank and the solvent III of the storage tank into a mixing tank to obtain a composite solvent, enabling the composite solvent to enter a second extraction tower, enabling deasphalted oil to enter the second extraction tower, enabling the deasphalted oil to be in reverse contact with the composite solvent in the second extraction tower, enabling saturated hydrocarbon components to flow out of the top of the second extraction tower, enabling aromatic hydrocarbon components and the composite solvent to flow out of the bottom of the second extraction tower, enabling the aromatic hydrocarbon components and the composite solvent to enter a second solvent recovery tower to obtain aromatic hydrocarbon components, and recovering the composite solvent to the storage tank for recycling. The invention can obtain the aromatic hydrocarbon component and the saturated hydrocarbon component with better quality in a more efficient and environment-friendly way.)

1. A method for separating aromatic hydrocarbon and saturated hydrocarbon in catalytic cracking slurry oil through a composite solvent is characterized by comprising the following steps;

the catalytic cracking slurry oil from the storage tank (4) enters a first extraction tower (6) from the upper part of the tower, a solvent I from the storage tank (5) enters the first extraction tower (6) from the lower part of the tower, the catalytic cracking slurry oil and the solvent I are in reverse contact in the first extraction tower (6) for extraction, the catalytic cracking slurry oil is separated into deasphalted oil and asphaltene components, the asphaltene components flow out from the bottom of the first extraction tower (6) for collection, the deasphalted oil and the solvent I flow out from the top of the first extraction tower (6) together, and then enter a solvent recovery tower (8), the solvent I is separated from the deasphalted oil to obtain deasphalted oil, and the solvent I is recovered to a storage tank (11) for recycling;

pumping a solvent II from a storage tank (1) and a solvent III from a storage tank (2) into a mixing tank (3) together according to a certain mass ratio, fully mixing under a certain operation condition to obtain a composite solvent, enabling the composite solvent to enter a second extraction tower (7) from the upper part of the tower, enabling deasphalted oil of a solvent recovery tower (8) to enter the second extraction tower (7) from the lower part of the tower, enabling the deasphalted oil and the composite solvent to be in reverse contact in the second extraction tower (7) for extraction, separating the deasphalted oil into a saturated hydrocarbon component and an aromatic hydrocarbon component in the second extraction tower (7), enabling the saturated hydrocarbon component to flow out of the top of the second extraction tower (7), collecting the aromatic hydrocarbon component and the composite solvent, enabling the aromatic hydrocarbon component and the composite solvent to flow out of the bottom of the second extraction tower (7) and enter a solvent recovery tower (9), separating the composite solvent from the aromatic hydrocarbon component to obtain the aromatic hydrocarbon component, and recovering the composite solvent to the storage tank (10), can be recycled.

2. The method for separating aromatic hydrocarbon and saturated hydrocarbon in catalytic cracking slurry oil through the composite solvent as claimed in claim 1, wherein the solvent I is one or more of C7-C12 normal/isoparaffin, the solvent II is furfural, and the solvent III (auxiliary agent) is one of polar solvents or auxiliary agents such as N, N-dimethylformamide, sulfolane, dimethyl sulfoxide, N-methylpyrrolidone, alpha-pyrrolidone, aromatic amine antioxidant, butyl methacrylate and the like.

3. The method for separating aromatic hydrocarbon and saturated hydrocarbon in catalytic cracking slurry oil by using the composite solvent as claimed in claim 1, wherein the composite solvent is obtained by mixing solvent II and solvent III (auxiliary agent), the mixing ratio is 2% -50% (the mass of the solvent III accounts for the total mass), the mixing heating temperature is 20-60 ℃, and the stirring speed is 20-200 r/min.

4. The method for separating aromatic hydrocarbons and saturated hydrocarbons in catalytic cracking slurry oil through the composite solvent as claimed in claim 1, wherein the extraction operating conditions of the first extraction tower are as follows: the operation temperature is 30-110 ℃ (preferably 40-70 ℃), the pressure is 0.1-10MPa (preferably 0.5-2.0MPa), and the mass ratio of the solvent I to the catalytic cracking slurry oil is 2:1-15:1 (preferably 3:1-8: 1).

5. The method for separating aromatic hydrocarbons and saturated hydrocarbons in catalytic cracking slurry oil through the composite solvent as claimed in claim 1, wherein the extraction operating conditions of the second extraction tower are as follows: the operation temperature is 25-90 deg.C (preferably 25-45 deg.C), the pressure is 0.2-15MPa (preferably 0.5-1.5MPa), and the mass ratio of composite solvent and deasphalted oil is 1:1-10:1 (preferably 1:1-4: 1).

Technical Field

The invention belongs to the technical field of separating aromatic hydrocarbons and saturated hydrocarbons by using a composite extraction solvent, and particularly relates to a method for separating aromatic hydrocarbons and saturated hydrocarbons in catalytic cracking slurry oil by using a composite solvent.

Background

The catalytic cracking slurry oil is unconverted hydrocarbon with boiling point higher than 350 deg.c in the catalytic cracking process, and has rich colloid and asphaltene, high viscosity and high density. At present, domestic catalytic slurry oil is generally delivered as cheap heavy fuel oil. In recent years, a great deal of research has been conducted on the properties of catalytic cracking slurry oil and the rational utilization technology thereof. The researches mainly relate to the combination of catalytic slurry oil and an oil refining process to reasonably utilize catalytic cracking slurry oil or the research of utilization technology for producing chemical products according to the characteristics of the composition of the catalytic cracking slurry oil so as to obtain products with high added value of the catalytic slurry oil and determine a deep processing scheme of the slurry oil. Because the oil slurry contains 30-50% of saturated hydrocarbon which is a high-quality catalytic cracking raw material, and meanwhile, the aromatic hydrocarbon in the oil slurry reaches over 50%, the aromatic hydrocarbon is a valuable chemical product, can be further deeply processed to produce a product with a higher added value, and has wide application and wide market prospect. Therefore, the comprehensive utilization of the catalytic slurry oil can bring good economic benefits to oil refining enterprises.

The current research result shows that the method of solvent extraction is one of feasible comprehensive utilization methods for further processing and treating the catalytic cracking heavy oil. Through the solvent extraction method, the obtained aromatic hydrocarbon can be used as a raw material for preparing high-value-added chemicals such as BTX, rubber filling oil, mesophase pitch and the like, and the obtained saturated hydrocarbon can be used as a raw material blending component of a high-quality catalytic cracking device, so that the raw material feeding composition is improved, the yield of light oil products is increased, and the economic benefit of the whole device is improved.

200810023335.X discloses a separation method for catalytic cracking slurry oil, which can simultaneously remove the liquid-solid separation of solid catalyst particles and the liquid-liquid separation between saturated hydrocarbon and aromatic hydrocarbon, and the method adds a phthalein amine solvent to separate the saturated hydrocarbon and the aromatic hydrocarbon in the slurry oil, and transfers the solid particles into the saturated hydrocarbon, although the separation is completed in one step, the solid powder is not completely separated, but only transferred into the saturated hydrocarbon component, and the part of the solid particles is not completely discharged. If the saturated hydrocarbon components are returned to the catalytic cracking unit, the unit is affected because the solid particles in this portion have a smaller particle size than the catalyst used in the original unit. There is therefore a need for a method which enables thorough removal of the catalyst powder, so that adverse effects on the apparatus are avoided.

CN103387844A discloses a method for separating catalytic cracking slurry oil, which adopts a two-stage extraction mode, takes furfural, N-methyl pyrrolidone and phenol as polar solvents, and C5-C12 alkane and cycloalkane as non-polar solvents to separate the catalytic cracking slurry oil into two parts of saturated hydrocarbon components and aromatic hydrocarbon components. The process does not demonstrate the effectiveness of removing sulfur, nitrogen and metal components from the aromatic hydrocarbon and does not provide further separation of asphaltenes and gums in the aromatic hydrocarbon component.

CN102453503A discloses a method for separating catalytic cracking slurry oil, which adopts a secondary extraction mode, wherein a first solvent is furfural, sulfolane, sulfoxide, N-methylpyrrolidone or amide; the second solvent is light oil, C6-C10 normal alkane or C6-C10 cycloparaffin. From the results of the examples of the method, the separation is not thorough, the content of colloid and asphaltene in the aromatic hydrocarbon component is more than 10 percent, and the aromatic hydrocarbon component cannot be directly processed into high value-added products.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a method for separating aromatic hydrocarbon and saturated hydrocarbon in catalytic cracking slurry oil by using a composite solvent, wherein the aromatic hydrocarbon component and the saturated hydrocarbon component with better quality are obtained in a more efficient and environment-friendly manner by adjusting the process sequence of double-solvent extraction and simultaneously introducing other polar solvents or auxiliary agents and a second solvent (polar solvent) to be compounded to serve as the composite solvent.

In order to achieve the purpose, the invention adopts the technical scheme that:

a method for separating aromatic hydrocarbon and saturated hydrocarbon in catalytic cracking slurry oil through a composite solvent comprises the following steps;

the catalytic cracking slurry oil from the storage tank 4 enters a first extraction tower 6 from the upper part of the tower, a solvent I from the storage tank 5 enters the first extraction tower 6 from the lower part of the tower, the catalytic cracking slurry oil and the solvent I are in reverse contact in the first extraction tower 6 for extraction, the catalytic cracking slurry oil is separated into deasphalted oil and asphaltene components, the asphaltene components flow out from the bottom of the first extraction tower 6 for collection, the deasphalted oil and the solvent I flow out from the top of the first extraction tower 6 together and then enter a solvent recovery tower 8, the solvent I is separated from the deasphalted oil to obtain deasphalted oil, and the solvent I is recovered to a storage tank 11 for recycling;

the method comprises the following steps of pumping a solvent II from a storage tank 1 and a solvent III from a storage tank 2 into a mixing tank 3 together according to a certain mass ratio, fully mixing under certain operation conditions to obtain a composite solvent, enabling the composite solvent to enter a second extraction tower 7 from the upper part of the tower, enabling deasphalted oil of a solvent recovery tower 8 to enter the second extraction tower 7 from the lower part of the tower, enabling the deasphalted oil and the composite solvent to reversely contact in the second extraction tower 7 for extraction, separating the deasphalted oil into a saturated hydrocarbon component and an aromatic hydrocarbon component in the second extraction tower 7, enabling the saturated hydrocarbon component to flow out of the top of the second extraction tower 7 for collection, enabling the aromatic hydrocarbon component and the composite solvent to flow out of the bottom of the second extraction tower 7 together, enabling the aromatic hydrocarbon component and the composite solvent to enter a solvent recovery tower 9, separating the composite solvent from the aromatic hydrocarbon component to obtain the aromatic hydrocarbon component, and recovering the composite solvent to the storage tank 10 for recycling.

The solvent I is one or more than one of C7-C12 normal/isoparaffin, the solvent II is furfural, and the solvent III (auxiliary agent) is one of polar solvents or auxiliary agents such as N, N-dimethylformamide, sulfolane, dimethyl sulfoxide, N-methylpyrrolidone, alpha-pyrrolidone, aromatic amine antioxidant, butyl methacrylate and the like.

The composite solvent is obtained by mixing a solvent II and a solvent III (an auxiliary agent), wherein the mixing proportion is 2-50% (the mass of the solvent III accounts for the total mass), the mixing heating temperature is 20-60 ℃, and the stirring speed is 20-200 r/min.

The extraction operating conditions of the first extraction tower are as follows: the operation temperature is 30-110 ℃ (preferably 40-70 ℃), the pressure is 0.1-10MPa (preferably 0.5-2.0MPa), and the mass ratio of the solvent I to the catalytic cracking slurry oil is 2:1-15:1 (preferably 3:1-8: 1).

The extraction operating conditions of the second extraction tower are as follows: the operation temperature is 25-90 deg.C (preferably 25-45 deg.C), the pressure is 0.2-15MPa (preferably 0.5-1.5MPa), and the mass ratio of composite solvent and deasphalted oil is 1:1-10:1 (preferably 1:1-4: 1).

The invention has the beneficial effects that:

the invention adjusts the traditional double-solvent extraction process route, leads the alkane extraction operation to be preposed, leads the aromatic extraction operation to be postpositioned, can better remove the asphaltene component in the oil slurry under the process route to obtain the deasphalted oil which does not contain asphaltene and contains less colloid, simultaneously removes most of sulfur and nitrogen heteroatoms and solid particles which are enriched in the asphaltene together, and finally obtains the aromatic hydrocarbon and saturated hydrocarbon components which do not contain the solid particles, and have extremely low sulfur and nitrogen heteroatom content, and the aromatic hydrocarbon components contain extremely low content of multielement condensed ring aromatic hydrocarbons such as colloid and the like.

The second solvent (polar solvent) in the traditional double-solvent extraction technology is compounded, different solvent types and different proportions can be prepared according to different target products, and the obtained composite solvent has the different characteristics of small using amount, high selectivity, high yield of target components, deep desulfurization and denitrification, low energy consumption and the like.

The composite solvent is used for extracting the deasphalted oil, so that a small amount of sulfur and nitrogen compounds in the deasphalted oil can be further removed, and meanwhile, due to the high selectivity of the composite solvent, the aromatic hydrocarbon component and the saturated hydrocarbon component with high quality and high yield can be finally obtained and can be directly used as raw materials for producing high-added-value products such as needle coke, chemical solvents and the like.

Description of the drawings:

FIG. 1 is a schematic diagram of the system of the present invention.

Detailed Description

The present invention will be described in further detail with reference to examples.

Example 1

The embodiment provides a method for separating aromatic hydrocarbon and saturated hydrocarbon in catalytic cracking slurry oil by using a composite solvent, which is carried out by using an extraction tower, and the specific flow is shown in figure 1. The method comprises the following steps:

the catalytic cracking slurry oil from the storage tank 4 enters a first extraction tower 6 from the upper part of the tower, n-octane from the storage tank 5 as a solvent I enters the first extraction tower 6 from the lower part of the tower, the catalytic cracking slurry oil and the n-octane are in reverse contact in the tower, extraction is carried out under the conditions that the operation temperature is 60 ℃, the pressure is 0.5MPa and the mass ratio of the solvent to the oil is 4:1, the catalytic cracking slurry oil is separated into deasphalted oil and asphaltene components, the asphaltene components flow out from the bottom of the first extraction tower 6 and are collected, the deasphalted oil and the n-octane flow out from the top of the first extraction tower 6 together, then the deasphalted oil and the deasphalted oil enter a solvent recovery tower 8, the n-octane is separated to obtain deasphalted oil, and the n-octane is recovered to a storage tank 11 and recycled.

Pumping solvent II furfural from a storage tank 1 and solvent III N-methyl pyrrolidone from a storage tank 2 into a mixing tank 3 together according to a mass ratio of 8:2, fully mixing under the conditions that the heating temperature is 30 ℃ and the stirring speed is 150r/min to obtain a composite solvent A, enabling the composite solvent A to enter a second extraction tower 7 from the upper part of the tower, enabling deasphalted oil to enter the second extraction tower 7 from the lower part of the tower, enabling the deasphalted oil and the composite solvent A to be in reverse contact in the tower, extracting under the conditions that the operation temperature is 35 ℃, the pressure is 0.5MPa and the solvent-oil mass ratio is 1:1, separating the deasphalted oil in the tower into a saturated hydrocarbon component and an aromatic hydrocarbon component, enabling the saturated hydrocarbon component to flow out from the top of the second extraction tower 7, collecting, enabling the aromatic hydrocarbon component and the composite solvent A to flow out from the bottom of the second extraction tower 7, enabling the aromatic hydrocarbon component to enter a solvent recovery tower 9, and separating the composite solvent A from the aromatic hydrocarbon component, to obtain aromatic hydrocarbon component, and the composite solvent A is recycled to the storage tank 10 for recycling.

By changing the operation conditions of different composite solvents and second extraction columns, example 2, example 3, comparative example 1 and comparative example 2 were realized while keeping the conditions of the raw materials, the operation conditions of the first extraction column, the operation conditions of the mixing tank, and the like unchanged.

TABLE 1 properties of catalytically cracked oil slurries

TABLE 2 variation of conditions in the extraction section

TABLE 3 basic Properties of saturated hydrocarbon Components

Item	Example 1	Example 2	Example 3	Comparative example 1	Comparative example 2
						Yield of saturated hydrocarbon component/wt%	95.12	96.32	96.45	94.65	95.01
Saturated hydrocarbon/wt%	82.1	83.2	81.5	74.3	81.7
						Aromatic hydrocarbon/wt%	17.9	16.8	18.5	25.7	18.3
Colloid, asphaltene/wt%	0	0	0	0	0
						Solid content/wt％	0	0	0	0	0
S/wt％	0.027	0.024	0.018	0.075	0.045
						N/wt％	0.048	0.037	0.023	0.11	0.069

TABLE 4 basic Properties of the aromatic component