Solvent refining method for producing environment-friendly rubber plasticizer

Abstract

The invention relates to the technical field of petrochemical engineering, in particular to a solvent refining method for producing an environment-friendly rubber plasticizer. The method comprises the following steps: taking solvent extract oil of lubricating oil as a raw material, carrying out extraction in a counter-current extraction tower by adopting a two-tower extraction process to obtain the aryl environment-friendly rubber plasticizer, mixing extract liquids at the bottoms of an extraction tower I and an extraction tower II, and recovering a solvent to obtain secondary extract oil. According to the invention, the content of polycyclic aromatic hydrocarbon in the raw material oil can be greatly reduced, and the content of environment-friendly low-cyclic aromatic hydrocarbon is reserved, so that the yield of the produced environment-friendly rubber plasticizer product is higher, and the CA value of the product is higher.

Description

Technical Field:

[0001] The present invention relates to the technical field of petrochemical engineering, and particularly relates to a solvent refining method for producing an environment-friendly rubber plasticizer. Background Art:

[0002] The oils used in the process of rubber synthesis or rubber processing are collectively referred to as rubber oils, also known as rubber plasticizers. Rubber plasticizers are one of the important raw materials for rubber processing, and are divided into aromatic type, naphthenic type and paraffinic type. Among them, aromatic type oils have the characteristics of high density, high viscosity, good affinity and excellent processing performance, and have excellent properties such as good compatibility with rubber and the ability to endow tires with good wet skid resistance. This type of oil is represented by the extract oil (DAE) refined from lubricating oil solvents, which contains a large amount of polycyclic aromatic hydrocarbon compounds. Polycyclic aromatic hydrocarbons are toxic such as carcinogenic and damaging the reproductive system, so they are limited in use by some developed countries. The European Union issued Directive 2005 / 69 / EC on December 9, 2005, requiring that since January 1, 2010, in all tires and rubber products entering the EU market, the total amount of 8 harmful polycyclic aromatic hydrocarbons listed in the filling oil used shall not exceed 10 mg per kilogram, and the content of benzo[a]pyrene (BaP) shall not exceed 1 mg per kilogram.

[0003] In recent years, the domestic tire industry has developed rapidly. As a major tire manufacturing country, China's tire oil has become the largest application field of rubber oil, and more than one-third of domestic tires are exported overseas. At present, there are mainly two types of domestic environment-friendly rubber plasticizers: aromatic-based mineral oil and naphthenic-based mineral oil. Among them, aromatic-based mineral oil is mainly used in tires and related products and as the filling oil for rubber.

[0004] In terms of the domestic market, with the continuous increase in automobile production, the tire production has also been showing a relatively fast upward trend. With the increase in investment by international well-known tire companies in China, the increase in the export volume of radial tires of domestic large enterprises and the trend of developing environment-friendly green products, the environment-friendly rubber plasticizer, as an environment-friendly rubber filling oil used in oil-filled rubber and tire production, will inevitably attract great attention and its demand will also increase.

[0005] In the production of environmentally friendly rubber plasticizers, some production methods have been proposed at home and abroad. For example, CN200910050832.3 proposes using solvents such as furfural and phenol to extract and remove polycyclic aromatic hydrocarbons in the raw material oil, and then recovering the solvent to obtain environmentally friendly aromatic oil. The problem with this method is that it is difficult to produce products with high yield, high aromatic hydrocarbon content, and quality meeting EU requirements simply by using traditional solvent extraction processes. CN200910088932.5 proposes another refining method, that is, contacting the third-stage reduced crude oil with furfural in a countercurrent extraction column as described above, obtaining refined oil after recovering the solvent, and then subjecting the refined oil to re-extraction. The extracted oil obtained from the secondary extraction is environmentally friendly rubber oil. This technology still has problems such as low yield of environmentally friendly oil and low aromatic hydrocarbon content in the environmentally friendly oil (i.e., low aromatic carbon rate C A low).

[0006] Using existing solvent refining technologies, it is difficult to produce environmentally friendly rubber plasticizer products with a C A value of more than 25%. Therefore, there is an urgent need to develop a production method for high-aromatic environmentally friendly rubber plasticizers. Summary of the Invention:

[0007] The technical problem to be solved by the present invention is to provide a solvent refining method for producing environmentally friendly rubber plasticizers. This method can significantly reduce the content of polycyclic aromatic hydrocarbons in the raw material oil and retain the content of environmentally friendly less-ring aromatic hydrocarbons, thereby achieving a higher yield of the produced environmentally friendly rubber plasticizer products and a higher C A value.

[0008] The technical solution adopted by the present invention is: a solvent refining method for producing environmentally friendly rubber plasticizers, which includes the following steps: using the solvent-extracted oil of lubricating oil as the raw material oil, proceeding in a countercurrent extraction column, adopting a two-column extraction process, using furfural as the solvent. After the raw material oil and the solvent are mixed, they enter the extraction column from the upper solvent inlet of Extraction Column I. The raffinate is obtained at the top of Extraction Column I. The raffinate of Extraction Column I is divided into two parts. One part enters the extraction column from the lower raw material inlet of Extraction Column I, and the other part of the raffinate enters the extraction column as the raw material of Extraction Column II from the lower part of Extraction Column II. The solvent enters the extraction column from the upper part of Extraction Column II. The raffinate is obtained at the top of Extraction Column II. After recovering the solvent, an aromatic-based environmentally friendly rubber plasticizer is obtained. The extracts at the bottoms of Extraction Column I and Extraction Column II are mixed and the solvent is recovered to obtain a secondary extract.

[0009] Further, the solvent-extracted oil of the lubricating oil satisfies an open flash point of not less than 200 °C, a kinematic viscosity at 100 °C of not less than 20.0 mm 2 / s, a C A value of not less than 35.0%, and a freezing point of not higher than 20 °C. If the freezing point is higher than 20 °C, dewaxing treatment can be carried out.

[0010] Further, the top temperature of the extraction tower I is 45°C - 55°C, the bottom temperature is 40°C - 45°C, and the mass ratio of the solvent entering the extraction tower I to the feedstock oil is 0.5 - 1.0:1.

[0011] Further, the mass ratio of a part of the raffinate entering the extraction tower I to the feedstock oil is 0.1 - 0.5:1.

[0012] Further, the top temperature of the extraction tower II is 55°C - 65°C, the bottom temperature is 40°C - 45°C, and the mass ratio of the solvent entering the extraction tower II to the feedstock oil is 0.6 - 1.0:1.

[0013] The beneficial effects of the present invention are as follows: The present invention can significantly reduce the content of polycyclic aromatic hydrocarbons in the feedstock oil and retain the content of environmentally friendly less-ring aromatic hydrocarbons, thereby achieving a higher yield of the environmentally friendly rubber plasticizer product produced and a higher C A value. BRIEF DESCRIPTION OF THE DRAWINGS:

[0014] The following further describes the present invention in detail with reference to the drawings and specific embodiments.

[0015] Figure 1 It is the process flow diagram of the present invention.

[0016] The reference numerals therein are respectively represented as: 1, extraction tower I; 2, extraction tower II; 3, feedstock oil; 4, solvent for extraction tower I; 5, raffinate of extraction tower I; 6, extract of extraction tower I; 7, raffinate of extraction tower II; 8, extract of extraction tower II; 9, solvent for extraction tower II. SPECIFIC EMBODIMENTS:

[0017] As Figure 1 shown, a solvent refining method for producing an environmentally friendly rubber plasticizer, the method comprising the following steps: carried out in a countercurrent extraction tower, adopting a two-tower extraction process, using furfural as the solvent, the feedstock oil 3 and the solvent 4 for extraction tower I are mixed and then enter the extraction tower from the upper solvent inlet of the extraction tower I 1. The raffinate 5 of the extraction tower I is obtained at the top of the extraction tower I 1. The raffinate is divided into two parts. One part enters the extraction tower from the lower feedstock inlet of the extraction tower I 1, and the other part of the raffinate enters the extraction tower as the feedstock of the extraction tower II 2 from the lower part of the extraction tower II 2. The solvent 9 for extraction tower II enters the extraction tower from the upper solvent inlet of the extraction tower II 2, and the raffinate 7 of the extraction tower II is obtained at the top. After recovering the solvent, an aromatic-based environmentally friendly rubber plasticizer is obtained. The extracts obtained at the bottoms of the extraction tower I 1 and the extraction tower II 2 are mixed and the solvent is recovered to obtain a secondary extract oil.

[0018] Example 1

[0019] Using the furfural extract oil of a certain vacuum gas oil from the fourth side stream of crude oil as the feedstock, the properties are shown in Table 1 in the appendix. The refining conditions of Extraction Column I are as follows: the temperature at the top of the column is 50 °C, the temperature at the bottom of the column is 40 °C, and the mass ratio of the solvent furfural to the feedstock is 0.5:1. The raffinate of Extraction Column I is divided into two parts. One part enters Extraction Column from the lower feed inlet of Extraction Column I, and the mass ratio of this part of the raffinate to the feedstock is 0.1:1. The remaining raffinate of Extraction Column I enters Extraction Column II as the feedstock from the lower feed inlet. The solvent furfural enters Extraction Column from the upper solvent inlet of Extraction Column II. The operating conditions of Extraction Column II are as follows: the temperature at the top of the column is 60 °C, the temperature at the bottom of the column is 40 °C, and the mass ratio of the solvent furfural to the feedstock is 0.6:1. After the refined liquid of Extraction Column II recovers the solvent, an environment-friendly rubber plasticizer is obtained, and the properties are shown in Table 1. The bottom extracts of Extraction Column I and Extraction Column II are mixed and the solvent is recovered to obtain a secondary extract oil.

[0020] Comparative Example 1

[0021] The same feedstock, extraction process conditions and extraction column as in Example 1 are used, that is, the temperature at the top of Extraction Column I is 50 °C, the temperature at the bottom of the column is 40 °C, the mass ratio of the solvent furfural to the feedstock is 0.5:1. The solvent enters Extraction Column from the upper part of Extraction Column I, and the feedstock enters Extraction Column from the lower part of Extraction Column I. The raffinate of Extraction Column I enters Extraction Column II as the feedstock from the lower part. The solvent furfural enters Extraction Column II from the upper part. The operating conditions of Extraction Column II are as follows: the temperature at the top of the column is 60 °C, the temperature at the bottom of the column is 40 °C, and the mass ratio of the solvent furfural to the feedstock is 0.6:1.0. After the refined liquid of Extraction Column II recovers the solvent, an environment-friendly rubber plasticizer is obtained, and the properties are shown in Table 1. The bottom extracts of Extraction Column I and Extraction Column II are mixed and the solvent is recovered to obtain a secondary extract oil.

[0022] Example 2

[0023] Using the furfural extract oil of naphthenic vacuum gas oil from the third side stream as the feedstock, the properties are shown in Table 2 in the appendix. The refining conditions of Extraction Column I are as follows: the temperature at the top of the column is 55 °C, the temperature at the bottom of the column is 40 °C, and the mass ratio of the solvent furfural to the feedstock is 1.0:1. The raffinate of Extraction Column I is divided into two parts. One part enters Extraction Column from the lower part of Extraction Column I, and the mass ratio of this part of the raffinate to the feedstock is 0.5:1. The remaining raffinate of Extraction Column I enters Extraction Column II as the feedstock from the lower part of Extraction Column II. The solvent furfural enters Extraction Column II from the upper part. The operating conditions of Extraction Column II are as follows: the temperature at the top of the column is 65 °C, the temperature at the bottom of the column is 45 °C, and the mass ratio of the solvent furfural to the feedstock is 1.0:1. After the refined liquid of Extraction Column II recovers the solvent, an environment-friendly rubber plasticizer is obtained, and the properties are shown in Table 1. The bottom extracts of Extraction Column I and Extraction Column II are mixed and the solvent is recovered to obtain a secondary extract oil.

[0024] Comparative Example 2

[0025] Using the same feedstock oil, extraction process conditions, and extraction column as in Example 2, the refining conditions for Extraction Column I are as follows: the top temperature of the column is 45°C, the bottom temperature is 40°C, the mass ratio of the solvent furfural to the feedstock oil is 1.0:1. The solvent enters the extraction column from the upper part of Extraction Column I, and the feedstock enters the extraction column from the lower part of Extraction Column I. The raffinate of Extraction Column I serves as the feedstock for Extraction Column II and enters Extraction Column II from the lower part. The solvent furfural enters Extraction Column II from the upper part. The operating conditions for Extraction Column II are: the top temperature of the extraction column is 65°C, the bottom temperature of the extraction column is 45°C, the mass ratio of the solvent furfural to the total feedstock oil is 1.0:1. After the refined liquid of Extraction Column II recovers the solvent, an environment-friendly rubber plasticizer is obtained, and its properties are shown in Table 2. The bottom draw of Extraction Column I and Extraction Column II is mixed and the solvent is recovered to obtain an extract oil.

[0026] Comparative Example 3

[0027] Using the same feedstock oil as in Example 2, the same top temperature of the extraction column is 45°C, the bottom temperature is 40°C, the mass ratio of the solvent furfural to the feedstock oil is 1.4:1. The solvent enters the extraction column from the upper part of the extraction column, and the feedstock enters the extraction column from the lower part of the extraction column. After the raffinate of the extraction column recovers the solvent, an environment-friendly rubber plasticizer is obtained, and its properties are shown in Table 2. The bottom draw of the extraction column is mixed and the solvent is recovered to obtain an extract oil.

[0028] Table 1 Properties of the feedstock oil and environment-friendly rubber plasticizer in Example 1

[0029]

[0030] Table 2 Properties of the feedstock oil and environment-friendly rubber plasticizer in Example 2

[0031]

[0032] From the product yields and properties of Examples 1 - 2 and Comparative Examples 1 - 3, it can be seen that in this method, the solvent and the feedstock oil are mixed and then enter the extraction column from the solvent inlet of Extraction Column I. Part of the raffinate of Extraction Column I serves as the feedstock and enters the extraction column from the feedstock inlet of Extraction Column I. The remaining raffinate of Extraction Column I serves as the feedstock for Extraction Column II. After the raffinate of Extraction Column II recovers the solvent, a high-aromatic environment-friendly rubber plasticizer is obtained. Compared with the conventional two-stage extraction, under the same conditions, the product yield and C A value can be increased; compared with the conventional single-stage extraction, the single-stage extraction requires a larger solvent ratio, and the product yield is lower and the C A value is smaller. Therefore, using the lubricating oil solvent extract oil as the feedstock oil, a high-aromatic environment-friendly rubber plasticizer product with a benzo[a]pyrene (BaP) content of less than 1 mg / kg, a PCA content of less than 3%, a total content of 8 harmful aromatic hydrocarbons of less than 10 mg / kg, and a C A value greater than 25% can be produced by this method.

[0033] It is understood that the above specific description of the present invention is only for the purpose of illustrating the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those of ordinary skill in the art should understand that the present invention can still be modified or equivalently replaced to achieve the same technical effects; as long as the use requirements are met, they are all within the protection scope of the present invention.

Claims

1. A solvent refining method for producing an environmentally friendly rubber plasticizer, characterized in that: The method comprises the following steps: using the solvent-extracted oil of lubricating oil as the feedstock, conducting the process in a countercurrent extraction column, adopting a two-column extraction process, using furfural as the solvent. After the feedstock and the solvent are mixed, they enter the extraction column from the upper solvent inlet of Extraction Column I. The raffinate is obtained at the top of Extraction Column I. The raffinate of Extraction Column I is divided into two parts. One part enters the extraction column from the lower feedstock inlet of Extraction Column I, and the other part of the raffinate enters the extraction column as the feedstock of Extraction Column II from the lower part of Extraction Column II. The solvent enters the extraction column from the upper part of Extraction Column II. The raffinate is obtained at the top of Extraction Column II. After recovering the solvent, an aromatic-based environmental protection rubber plasticizer is obtained. The extracts at the bottoms of Extraction Column I and Extraction Column II are mixed and the solvent is recovered to obtain a secondary extracted oil.

2. The solvent refining method for producing an environmentally friendly rubber plasticizer according to claim 1, characterized in that: The solvent-extracted oil of the lubricating oil meets the requirements that the flash point (open cup) is not less than 200 °C, the kinematic viscosity at 100 °C is not less than 20.0 mm 2 / s, the C A value is not less than 35.0%, and the freezing point is not higher than 20 °C. If the freezing point is higher than 20 °C, dewaxing treatment can be carried out.

3. The solvent refining method for producing an environmentally friendly rubber plasticizer according to claim 1, characterized in that: The top temperature of the said Extraction Column I is 45°C - 55°C, the bottom temperature is 40°C - 45°C, and the mass ratio of the solvent entering Extraction Column I to the said feedstock is 0.5 - 1.0:

1.

4. The solvent refining method for producing an environmentally friendly rubber plasticizer according to claim 1, characterized in that: The mass ratio of the part of the raffinate entering Extraction Column I to the said feedstock is 0.1 - 0.5:

1.

5. The solvent refining method for producing an environmentally friendly rubber plasticizer according to claim 1, characterized in that: The top temperature of the said Extraction Column II is 55°C - 65°C, the bottom temperature is 40°C - 45°C, and the mass ratio of the solvent entering Extraction Column II to the said feedstock is 0.6 - 1.0:1.

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