阅读说明：本技术 一种低芳烃原料的糠醛精制系统和精制工艺 (Furfural refining system and process for low-aromatic-hydrocarbon raw material ) 是由 林荣兴 刘海龙 黄存超 王辉 谢尉 袁晓杰 张峰 徐一方 于 2018-08-03 设计创作，主要内容包括：本发明涉及一种低芳烃原料的糠醛精制系统和精制工艺。该糠醛精制系统包括脱气塔、第一萃取塔、第二萃取塔、第一加热炉、第一汽提塔、第一蒸发塔、第二蒸发塔、第二加热炉、第二汽提塔、干燥塔和沉降罐,所述脱气塔与所述第一萃取塔连通,第一萃取塔塔顶与所述第二萃取塔连通,第二萃取塔塔顶、所述第一加热炉和所述第一汽提塔依次连通,第一萃取塔塔底和第二萃取塔塔底与所述第一蒸发塔连通,第一蒸发塔塔底、所述第二加热炉和所述第二蒸发塔依次连通,第一蒸发塔塔顶、第二蒸发塔塔顶与所述干燥塔连通。本发明的糠醛精制系统和工艺能够处理低芳烃原料,工艺运行稳定且得到了质量合格的精制油,提供了一种低芳烃原料的糠醛精制系统和精制工艺。(The invention relates to a furfural refining system and a furfural refining process for a low-aromatic hydrocarbon raw material. This furfural refining system includes degasser, first extraction tower, second extraction tower, first heating furnace, first stripping tower, first evaporating tower, second heating furnace, second stripping tower, drying tower and settling cask, the degasser with first extraction tower intercommunication, first extraction tower top with second extraction tower intercommunication, second extraction tower top first heating furnace with first stripping tower communicates in proper order, first extraction tower bottom and second extraction tower bottom with first evaporating tower intercommunication, first evaporating tower bottom the second heating furnace with the second evaporating tower communicates in proper order, first evaporating tower top, second evaporating tower top with the drying tower intercommunication. The furfural refining system and the process can treat low-aromatic-hydrocarbon raw materials, the process is stable to operate, refined oil with qualified quality is obtained, and the furfural refining system and the refining process for the low-aromatic-hydrocarbon raw materials are provided.)

1. A furfural refining system with low aromatic hydrocarbon raw material is characterized by comprising a degassing tower (1), a first extraction tower (2), a second extraction tower (3), a first heating furnace (4), a first stripping tower (5), a first evaporation tower (6), a second evaporation tower (7), a second heating furnace (8), a second stripping tower (9), a drying tower (10) and a settling tank (11), wherein the degassing tower (1) is communicated with the first extraction tower (2), the top of the first extraction tower is communicated with the second extraction tower (3), the top of the second extraction tower, the first heating furnace (4) and the first stripping tower (5) are communicated in sequence, the bottom of the first extraction tower and the bottom of the second extraction tower are communicated with the first evaporation tower (6), the bottom of the first evaporation tower, the second heating furnace (8) and the second evaporation tower (7) are communicated in sequence, the top of the first evaporation tower and the top of the second evaporation tower are communicated with the drying tower (10), the bottom of the second evaporation tower is communicated with the second stripping tower (9), the top of the first stripping tower and the top of the second stripping tower are communicated with the settling tank (11), the settling tank is provided with an oil phase outlet, a water phase outlet and an aldehyde phase outlet, the aldehyde phase outlet of the settling tank is communicated with the drying tower (10), the bottom of the drying tower is communicated with the first extraction tower (2), and/or the bottom of the drying tower is communicated with the second extraction tower (3).

2. The furfural refining system of a low aromatic hydrocarbon feedstock of claim 1 wherein the bottom of the second stripping tower is in communication with an outside sump oil tank.

3. The furfural refining system of a low aromatic hydrocarbon feedstock of claim 1 further comprising a dehydration tower (12), the aqueous phase outlet of the settling tank being in communication with the dehydration tower (12).

4. The furfural refining system of low aromatic hydrocarbon feedstock of claim 3 wherein a dehydration tower overhead communicates with the settling tank (11).

5. The furfural refining system of low aromatic hydrocarbon feedstock of claim 1 wherein an oil phase outlet of a settling tank is in communication with the first evaporation tower (6).

6. The furfural refining system of low aromatic hydrocarbon feedstock of claim 1 wherein a drying tower overhead communicates with the settling tank (11).

7. A furfural refining process of a low aromatic hydrocarbon feedstock, characterized by using the furfural refining system according to any one of claims 1 to 6, comprising the steps of:

1) degassing a low-aromatic hydrocarbon raw material by a degassing tower (1), then carrying out primary extraction by a first extraction tower (2) by taking furfural as an extractant to respectively obtain a first raffinate and a first extract, carrying out secondary extraction by a second extraction tower (3) by taking furfural as the extractant to respectively obtain a second raffinate and a second extract, heating the second raffinate by a first heating furnace (4) and carrying out steam stripping by a first steam stripping tower (5) to respectively obtain a mixture containing furfural and refined oil;

2) evaporating the first extract and the second extract obtained in the step 1) by a first evaporation tower (6) to obtain a first evaporation tower top product and a first evaporation tower bottom product, heating the first evaporation tower bottom product by a second heating furnace (8), evaporating by a second evaporation tower (7) to obtain a second evaporation tower top product and a second evaporation tower bottom product, and stripping the second evaporation tower bottom product by a second stripping tower (9) to respectively obtain a second stripping tower top product and extract oil;

3) settling the mixture containing furfural obtained in the step 1) and the second stripping tower top product obtained in the step 2) in a settling tank (11) to respectively obtain an oil phase product, a water phase product and an aldehyde phase product;

4) drying the first evaporation tower top product obtained in the step 2), the second evaporation tower top product obtained in the step 2) and the aldehyde phase product obtained in the step 3) by a drying tower (10) to obtain a drying tower top product and a drying tower bottom product;

5) the dried bottom product obtained in the step 4) is returned to the first extraction tower (2) and/or the second extraction tower (3) in the step 1) as an extracting agent.

8. The furfural refining process according to claim 7, wherein the extract oil obtained in step 2) is discharged to an external sump oil tank.

9. The furfural refining process according to claim 7, wherein the water phase product obtained in step 3) is dehydrated by a dehydration column (12) to obtain a dehydration column top product and a dehydration column bottom product, respectively.

10. The furfural refining process according to claim 9, characterized in that the dehydration column overhead is returned to the settling tank (11).

11. The furfural refining process of claim 9, further comprising one or more of the following features:

1) the mass ratio of the stripping amount of the dehydrating tower to the feeding amount of the dehydrating tower is 1.67-2.5%: 1;

2) the pressure of the dehydration tower is-70 KPa to-50 KPa.

12. The furfural refining process according to claim 7, characterized in that the drying overhead product obtained in step 4) is returned to the settling tank (11).

13. The furfural refining process according to claim 7, wherein the low aromatic hydrocarbon feedstock has a kinematic viscosity of 7-8 mm²S, aromatic content<6 wt% and a flash point of 155-170 ℃.

14. The furfural refining process of claim 7, further comprising one or more of the following characteristics in step 1):

1) the solvent ratio of the first-stage extraction is 1.3: 1-1.5: 1;

2) the tower top temperature of the first extraction tower is 97-105 ℃;

3) the tower bottom temperature of the first extraction tower is 50-60 ℃;

4) the tower bottom pressure of the first extraction tower is 550-650 kPa;

5) the interface of the first extraction tower is 10-70%;

6) the solvent ratio of the second-stage extraction is 1.7: 1-1.9: 1;

7) the tower top temperature of the second extraction tower is 99-107 ℃;

8) the temperature of the bottom of the second extraction tower is 50-60 ℃;

9) the tower bottom pressure of the second extraction tower is 600-750 kPa;

10) the interface of the second extraction tower is 10-70%;

11) the outlet temperature of the first heating furnace is 210-200 ℃;

12) the liquid level at the bottom of the first stripping tower is 30-50%;

13) the temperature at the bottom of the first stripping tower is not less than 190 ℃;

14) the mass ratio of the stripping amount of the first stripping tower to the feeding amount of the first stripping tower is 1.6-2.65%: 1;

15) the tower top temperature of the first stripping tower is 100-120 ℃.

15. The furfural refining process of claim 7, further comprising one or more of the following characteristics in step 2):

1) the tower top pressure of the first evaporation tower is 40-60 Pa;

2) the tower top pressure of the second evaporation tower is 95-110 Pa;

3) the outlet temperature of the second heating furnace is 215-205 ℃;

4) the temperature of the bottom of the second stripping tower is 150-157 ℃;

5) the mass ratio of the stripping amount of the second stripping tower to the feeding amount of the second stripping tower is 1.17-2%: 1;

6) the tower top temperature of the second stripping tower is 120-140 ℃.

16. The furfural refining process of claim 7, further comprising one or more of the following characteristics in step 4):

1) the pressure in the middle of the drying tower is 20-30 Pa;

2) the temperature of the bottom of the drying tower is 150-155 ℃;

3) the temperature of the top of the drying tower is 90-105 ℃.

Technical Field

The invention relates to the technical field of furfural refining, in particular to a furfural refining system and a refining process for low-aromatic-hydrocarbon raw materials.

Background

Lubricating oils are a large group of petroleum products. The proportion of the lubricating oil product is not large in terms of the consumption of the petroleum product, but the importance of the lubricating oil product is far more than the proportion of the lubricating oil product. Although the total amount of the lubricating oil is relatively small, the technical content is high, and the added value of the product is high, so the lubricating oil always occupies a very important position in the production process of petroleum refining.

At present, the conventional production flow of the lubricating oil component which is commonly adopted in China obtains various components of the lubricating oil base oil by a series of processing means such as solvent refining, solvent dewaxing, clay or hydrogenation supplementary refining on the basis of dividing various fractions suitable for producing the lubricating oil base oil through atmospheric and vacuum distillation. And mixing one or more base oil components according to a certain proportion according to requirements to obtain the base oil of various lubricating oils.

In the conventional production process of lubricating oil components, the main function of the solvent refining process is to remove the non-ideal components contained in the lubricating oil fraction and retain the ideal components so as to improve the viscosity-temperature characteristic, the anti-oxidation stability, the carbon residue value and the like of the lubricating oil.

Since 1909, the first solvent refining set in the world is put into use, the solvent refining process has been in the history of nearly one hundred years and has been in the vigorous development stage. However, since the middle of the 80's of the 20 th century, no new major breakthrough has appeared in the processing technology and equipment for solvent refining, and in addition, the development of the solvent refining technology is basically in a state of stagnation under the situation that various hydrogenation processes are continuously applied to the production process of lubricating oil at present.

Among the more commonly used solvents are furfural, phenol and N-methyl pyrrolidone (NMP). The aromatic hydrocarbon content of the feed of the currently operated furfural refining device is generally about 20-25%, and the operation disorder of a solvent recovery system can be caused by the excessively low aromatic hydrocarbon content.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, it is an object of the present invention to provide a furfural refining system and a refining process for a low aromatic hydrocarbon feedstock. The furfural refining system comprises a degassing tower, a first extraction tower, a second extraction tower, a first heating furnace, a first stripping tower, a first evaporation tower, a second heating furnace, a second stripping tower, a drying tower and a settling tank, wherein the degassing tower is communicated with the first extraction tower, the top of the first extraction tower is communicated with the second extraction tower, the top of the second extraction tower, the first heating furnace and the first stripping tower are sequentially communicated, the bottom of the first extraction tower and the bottom of the second extraction tower are communicated with the first evaporation tower, the bottom of the first evaporation tower, the second heating furnace and the second evaporation tower are sequentially communicated, the top of the first evaporation tower, the top of the second evaporation tower are communicated with the drying tower, the bottom of the second evaporation tower is communicated with the second stripping tower, the top of the first evaporation tower and the top of the second stripping tower are communicated with the settling tank, the settling tank is provided with an oil phase outlet, a second extraction tower, a second evaporation tower, a drying tower and a drying tower, And the aldehyde phase outlet of the settling tank is communicated with the drying tower, the bottom of the drying tower is communicated with the first extraction tower, and/or the bottom of the drying tower is communicated with the second extraction tower. The furfural refining system and the refining process can treat low-aromatic-hydrocarbon raw materials, the process is stable in operation, and refined oil with qualified quality is obtained.

In order to achieve the above and other related objects, a first aspect of the present invention provides a furfural refining system for low aromatic hydrocarbon feedstock, comprising a degassing tower, a first extraction tower, a second extraction tower, a first heating furnace, a first stripping tower, a first evaporation tower, a second heating furnace, a second stripping tower, a drying tower and a settling tank, wherein the degassing tower is communicated with the first extraction tower, the top of the first extraction tower is communicated with the second extraction tower, the top of the second extraction tower, the first heating furnace and the first stripping tower are communicated in sequence, the bottom of the first extraction tower and the bottom of the second extraction tower are communicated with the first evaporation tower, the bottom of the first evaporation tower, the second heating furnace and the second evaporation tower are communicated in sequence, the top of the first evaporation tower and the top of the second evaporation tower are communicated with the drying tower, the bottom of the second evaporation tower is communicated with the second stripping tower, the top of the first stripping tower and the top of the second stripping tower are communicated with the settling tank, the settling tank is provided with an oil phase outlet, a water phase outlet and an aldehyde phase outlet, the aldehyde phase outlet of the settling tank is communicated with the drying tower, the bottom of the drying tower is communicated with the first extraction tower, and/or the bottom of the drying tower is communicated with the second extraction tower.

Preferably, the bottom of the second stripping tower is communicated with an external sump.

Preferably, the device also comprises a dewatering tower, and the water phase outlet of the settling tank is communicated with the dewatering tower.

More preferably, the top of the dehydration column is in communication with the settling tank.

Preferably, the oil phase outlet of the settling tank is in communication with said first evaporation column.

Preferably, the top of the drying tower is communicated with the settling tank.

The second aspect of the invention provides a furfural refining process for a low-aromatic hydrocarbon raw material, which adopts the furfural refining system and comprises the following steps:

1) degassing a low-aromatic hydrocarbon raw material by a degassing tower, extracting by taking furfural as an extractant through a first extraction tower section to respectively obtain a first raffinate and a first extract, extracting by taking furfural as an extractant through a second extraction tower section to respectively obtain a second raffinate and a second extract, heating the second raffinate by a first heating furnace, and stripping by a first stripping tower to respectively obtain a mixture containing furfural and refined oil;

2) evaporating the first extract liquor and the second extract liquor obtained in the step 1) by a first evaporation tower to obtain a first evaporation tower top product and a first evaporation tower bottom product, heating the first evaporation tower bottom product by a second heating furnace, evaporating by a second evaporation tower to obtain a second evaporation tower top product and a second evaporation tower bottom product, and stripping the second evaporation tower bottom product by a second stripping tower to respectively obtain a second stripping tower top product and extract oil;

3) settling the mixture containing furfural obtained in the step 1) and the second stripping tower top product obtained in the step 2) in a settling tank to respectively obtain an oil phase product, a water phase product and an aldehyde phase product;

4) drying the first evaporation tower top product obtained in the step 2), the second evaporation tower top product obtained in the step 2) and the aldehyde phase product obtained in the step 3) by a drying tower to obtain a drying tower top product and a drying tower bottom product;

5) the dried bottom product obtained in the step 4) is used as an extracting agent and returned to the first extraction tower and/or the second extraction tower in the step 1).

Preferably, the extract oil obtained in the step 2) is discharged to an external dirty oil pool.

Preferably, the water phase product obtained in step 3) is dehydrated by a dehydrating tower to obtain a dehydrating tower top product and a dehydrating tower bottom product respectively.

More preferably, the dehydration column overhead is returned to the settling tank.

More preferably, one or more of the following features are also included:

1) the mass ratio of the stripping amount of the dehydrating tower to the feeding amount of the dehydrating tower is 1.67-2.5%: 1;

2) the pressure of the dehydration tower is-70 KPa to-50 KPa.

Preferably, the dried overhead product from step 4) is returned to the settling tank.

Preferably, the kinematic viscosity of the low aromatic hydrocarbon raw material is 7-8 mm²(s) (40 ℃ C.), aromatic hydrocarbon content<6 percent and a flash point of 155-170 ℃. The hydrocracking diesel oil is subjected to component cutting by a vacuum fractionation systemObtaining the bottom reducing oil of the vacuum tower after cutting, and then obtaining the low aromatic hydrocarbon raw material after ketone-benzene dewaxing.

Preferably, step 1) further comprises one or more of the following features:

1) the solvent ratio of the first-stage extraction is 1.3: 1-1.5: 1, and the solvent ratio is the mass ratio of the extracting agent to the material entering the first extraction tower;

2) the tower top temperature of the first extraction tower is 97-105 ℃;

3) the tower bottom temperature of the first extraction tower is 50-60 ℃;

4) the tower bottom pressure of the first extraction tower is 550-650 kPa;

5) the interface of the first extraction tower is 10-70%;

6) the solvent ratio of the second-stage extraction is 1.7: 1-1.9: 1, and the solvent ratio is the mass ratio of the extracting agent to the material entering the second extraction tower;

7) the tower top temperature of the second extraction tower is 99-107 ℃;

8) the temperature of the bottom of the second extraction tower is 50-60 ℃;

9) the tower bottom pressure of the second extraction tower is 600-750 kPa;

10) the interface of the second extraction tower is 10-70%;

11) the outlet temperature of the first heating furnace is 210-200 ℃;

12) the liquid level at the bottom of the first stripping tower is 30-50%;

13) the temperature at the bottom of the first stripping tower is not less than 190 ℃;

14) the mass ratio of the stripping amount of the first stripping tower to the feeding amount of the first stripping tower is 1.6-2.65%: 1;

15) the tower top temperature of the first stripping tower is 100-120 ℃.

Preferably, step 2) further comprises one or more of the following features:

1) the tower top pressure of the first evaporation tower is 40-60 Pa;

2) the tower top pressure of the second evaporation tower is 95-110 Pa;

3) the outlet temperature of the second heating furnace is 215-205 ℃;

4) the temperature of the bottom of the second stripping tower is 150-157 ℃;

5) the mass ratio of the stripping amount of the second stripping tower to the feeding amount of the second stripping tower is 1.17-2%: 1;

6) the tower top temperature of the second stripping tower is 120-140 ℃.

Preferably, step 4) further comprises one or more of the following features:

1) the pressure in the middle of the drying tower is 20-30 Pa;

2) the temperature of the bottom of the drying tower is 150-155 ℃;

3) the temperature of the top of the drying tower is 90-105 ℃.

The invention provides a furfural refining system and a furfural refining process for a low-aromatic hydrocarbon raw material. The furfural refining system comprises a degassing tower, a first extraction tower, a second extraction tower, a first heating furnace, a first stripping tower, a first evaporation tower, a second heating furnace, a second stripping tower, a drying tower and a settling tank, wherein the degassing tower is communicated with the first extraction tower, the top of the first extraction tower is communicated with the second extraction tower, the top of the second extraction tower, the first heating furnace and the first stripping tower are sequentially communicated, the bottom of the first extraction tower and the bottom of the second extraction tower are communicated with the first evaporation tower, the bottom of the first evaporation tower, the second heating furnace and the second evaporation tower are sequentially communicated, the top of the first evaporation tower, the top of the second evaporation tower are communicated with the drying tower, the bottom of the second evaporation tower is communicated with the second stripping tower, the top of the first evaporation tower and the top of the second stripping tower are communicated with the settling tank, the settling tank is provided with an oil phase outlet, a second extraction tower, a second evaporation tower, a drying tower and a drying tower, And the aldehyde phase outlet of the settling tank is communicated with the drying tower, the bottom of the drying tower is communicated with the first extraction tower, and/or the bottom of the drying tower is communicated with the second extraction tower. The furfural refining system and the refining process can treat low-aromatic-hydrocarbon raw materials, the process is stable in operation, and refined oil with qualified quality is obtained.

Drawings

Fig. 1 is a schematic diagram of a furfural refining system for a low aromatic feedstock of the present invention.

1-a degassing column;

2-a first extraction column;

3-a second extraction column;

4-a first heating furnace;

5-a first stripping column;

6-a first evaporation column;

7-a second evaporation column;

8-a second heating furnace;

9-a second stripping column;

10-a drying tower;

11-a settling tank;

12-dehydration column.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

The kinematic viscosity of the low aromatic hydrocarbon raw material is 7-8 mm²S, aromatic content<6 percent and flash point of 155-170 ℃, which are lower than the conventional raw materials, and the specific typical properties are shown in the following table:

index (I)	Low aromatic feedstock	Conventional raw materials
			Kinematic viscosity (40 ℃ C.), mm2/s	7～8	13～15
Kinematic viscosity (100 ℃ C.), mm2/s	2.2～2.5	3～3.5
			Aromatic content,% (mass fraction)	5～6	20～25
Freezing point, deg.C	-24～-18	-24～-18
			Chroma, number (Saishi color comparison)	+15～+19	/
Color number	/	<1.0
			Flash point (closed mouth), deg.C	155～170	170～180

A furfural refining system for low aromatic hydrocarbon raw materials, as shown in figure 1, comprises a degassing tower 1, a first extraction tower 2, a second extraction tower 3, a first heating furnace 4, a first stripping tower 5, a first evaporation tower 6, a second evaporation tower 7, a second heating furnace 8, a second stripping tower 9, a drying tower 10 and a settling tank 11, wherein the degassing tower 1 is communicated with the first extraction tower 2, the top of the first extraction tower is communicated with the second extraction tower 3, the top of the second extraction tower, the first heating furnace 4 and the first stripping tower 5 are communicated in sequence, the bottom of the first extraction tower and the bottom of the second extraction tower are communicated with the first evaporation tower 6, the bottom of the first evaporation tower, the second heating furnace 8 and the second evaporation tower 7 are communicated in sequence, the top of the first evaporation tower and the top of the second evaporation tower are communicated with the drying tower 10, the bottom of the second evaporation tower is communicated with the second stripping tower 9, the top of the first stripping tower and the top of the second stripping tower are communicated with the settling tank 11, the settling tank is provided with an oil phase outlet, a water phase outlet and an aldehyde phase outlet, the aldehyde phase outlet of the settling tank is communicated with the drying tower 10, the bottom of the drying tower is communicated with the first extraction tower 2, and the bottom of the drying tower is communicated with the second extraction tower 3. The bottom of the second stripping tower is communicated with an external sump oil pool. The refining system also comprises a dehydrating tower 12, a water phase outlet of the settling tank is communicated with the dehydrating tower 12, and the top of the dehydrating tower is communicated with the settling tank 11. The oil phase outlet of the settling tank is communicated with the first evaporation tower 6. The top of the drying tower is communicated with the settling tank 11.