SU789467A1 - Method of isolating aromatic hydrocarbons from their mixtures with nonaromatics - Google Patents

Description

The invention relates to the separation of aromatic hydrocarbons from hydrocarbon mixtures and may find application in the oil refining and petrochemical industries. 5

Known methods for the separation of aromatic hydrocarbons from mixtures with paraffinic or naphthenic hydrocarbons by liquid extraction using diethylene glycol (DEG) and triethylene glycol (TEG) as a selective solvent [1].

The disadvantages of such methods are low solubility and, as a result, high energy costs during the process, due to the high temperature (approximately 150 ° C) and a ratio of 20 between the extractant and the feed (3001200 wt.%).

The closest to the described invention in technical essence and the achieved result is a 25 method for the separation of aromatic hydrocarbons from their mixtures with non-aromatic by liquid extraction with a selective solvent based on caprolactam [2 ^ · 30

In the known method as a selective solvent using a mixture containing,%:

N-methylcaprolactam (Ν-MKL) 20-80

E-caprolactam or ethanol amine (E.-CL) 5-40

Ethylene glycol (eg) Else

However, insufficiently high extraction parameters of the solvent (low degree of extraction, selectivity) are the reason for the insufficiently high efficiency of this method.

The purpose of the invention is to increase the efficiency of the extraction process by increasing the degree of extraction of aromatic hydrocarbons, lowering the process temperature and the multiplicity of the solvent to the feedstock, which leads to an increase in the productivity of the applied equipment and, as a result, reduces the size of capital investments and energy costs.

The goal is achieved by the described method for the separation of hydrocarbons from mixtures thereof with non-aromatic liquid extraction using ξ-caprolactam or H-methylcaprolactam as a selective solvent, additionally containing 70-90 wt.% Dimethyl sulfoxide (dmso).

A distinctive feature is the use of N-KP or E-MKL as a selective solvent, additionally containing 70-90 weight. % DDMSO) 1

This method is illustrated by the following examples.

Example 1. A hydrocarbon mixture consisting of 35 wt.% Toluene and 65 wt.% Heptane, i.e. 7 g of toluene and .13 g of heptane are subjected to extrusion at 4 ° C. 20 g of a mixed solvent consisting of 10 wt.% E-CL and 90 wt.% DMSO, i.e. 2 g of E-CL and 18 g of DMSO. Extraction is carried out in one step in the apparatus type mixer sump. The mixture of the solvent with the raw material is first thermostat-controlled for 15-20 minutes, and then the mixer with electric drive-I is intensively mixed for 30 minutes. Then, sedimentation is carried out until the raffinate and extract phases are completely transparent, after which they are separated.

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The extraction of the extract from the extract phase is carried out by atmospheric distillation in the presence of water vapor.

The solvent is removed from the raffinate solution by water washing (300,400% by weight of water per raffinate solution) until the refractive index of the wash water is equal to 1.3333. The resulting raffinate and extract are dried by MsAA zeolite.

The toluene content in the extract and raffinate is determined by chromatographic method.

The results of the experiment are shown in the table.

PRI me R 2. The extraction is carried out according to example 1, but 20 g of solvent contain 20 wt.% E -KL and 80 wt.% DMSO, i.e. 4 g of 8-CL and 16 g of DMSO.

Example 3. The extraction is carried out according to example 1, but 20 g of the solvent contains 45 wt. 30 wt.% E-CL and 70 wt.% DMSO, i.e. 6 g €. -KL and 14 g of DMSO.

PRI me R. 4. The extraction is carried out according to example 1, but 20 g of solvent contain 10 wt.% N-MKL (2 g) and. 90 weight. % DMSO (13 g).

PRI me R 5. The extraction is carried out according to example 1, but 20 g of solvent contain 20 wt.% N-MKL (4 g) and 80 wt.% DMSO (16 g).

Example 6. The extraction is carried out according to example 1, but 20 g of solvent contain 30 wt.% N-MLC and 70 wt.% DMSO, i.e. 6 g of N-MKL and 14 g of DMSO.

The table shows the results of extraction according to examples 1-6, as well as data on extraction by a known device.

The process is carried out at lower temperatures of 40 ° C, instead of 60 ° C.

The most optimal composition is a mixed solvent containing 20 wt.% E-CL or (K-MKL) + + 80 wt.% DMSO, since the use of such a solvent can improve the selectivity of the process by approximately 1.8 times while increasing the degree of retrieving the target component.

The table also shows the results. tats of one-stage extraction before - * _ lagaemm solvent fr. reforming catalysis 62-10! r C, containing 32.3 wt.% aromatic hydrocarbons, including benzene - 10.7 wt.%, (toluene - 20.1 wt.%, xylene 1.5 wt.%.

An analysis of the tabular data shows that the use of the proposed solvent allows to significantly improve the performance of the known method for the allocation of aromatic hydrocarbons. Namely, the temperature of the process is reduced by 20 ° C, the ratio of the solvent to the feed is 3-4 times, the degree of extraction of the target product is increased, the separation selectivity is improved 1.7 times.

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Claims (2)

This invention relates to the isolation of aromatic hydrocarbons from hydrocarbon mixtures and may find application in the petroleum refining and non-chemical industries. Methods are known for separating aromatic hydrocarbons from mixtures with paraffin or naphthenic hydrocarbons using a solvent extraction method using diethylene glycol (DEG) and triethylene glycol (TEG) as a selective solvent. during the process due to high temperature (approximately) and the ratio between the extractant and the raw material (ZOO1200 wt.%). The closest to the described invention according to the technical essence and achievable result is the method of separation of aromatic hydrocarbons from their mixtures with non-aromatic by solvent extraction with a selective solvent based on caprolactam РЗ. In the known method, a mixture containing,%: N-methylcaprolactamfN-MCL} 20-80 E-caprolactam or ethanol amine (E-CL} 5-40 Ethylene glycol (ER)) is used as a selective solvent. However, the extracting indicators are not high enough degree of extraction, selectivity) are the reason for the insufficiently high efficiency of this method. solvent to raw materials, which causes an increase in the productivity of the equipment used and as a result reduces the size of capital investments and energy costs. The goal is achieved using a method of separating hydrocarbons from their mixtures with non-aromatic solvent extraction using selective caprolactam or N-methyl caprolactam as a selective solvent additionally containing 70-90% by weight of dimethyl sulfoxide (DMSO). A distinctive feature is the use of N-CL or t-MCL as a selective solvent, additionally containing 70-90 wt.% :( flMCO. This method is illustrated by the following examples. Example 1. Hydrocarbon consisting of 35 wt.% Toluene and 65 wt.% heptane, i.e., 7 g of toluene and .13 g of heptane are subjected to 20 g of a mixed solvent, consisting of 10 wt.% of E-CL and 90 wt.% of DMSO, i.e. 2 g S-CL and 18 g DMSO. Extraction is carried out in one step in a separator-type apparatus. A mixture of solvent and raw materials at the beginning, thermostatically for 1520 min, and then with an electric stirrer, vigorously stirred for 30 minutes, followed by settling to full transparency of the raffinate and extract phases, after which they were separated.The extraction of the extract from the extract phase was carried out by atmospheric distillation in the presence of water vapor. the raffinate solution was removed by diluting with water (300400 wt.% water per raffinate solution until refractive index Tj was obtained, ° washing water equal to 1.3333. The raffinate and extract obtained were dried with Hs A zeolite. Content oluola in the extract and the raffinate was determined by chromatographic technique. The results of the experiment are shown in the table. PRI mme R 2. Extraction is carried out as in Example 1, but 20 g of solvent contain 20% by weight -101 and 80 weight of DMSO, i.e. 4 GB-KL and 16 g of DMSO. EXAMPLE 3 Extraction is carried out as in Example 1, but 20 g of solvent contain 30% by weight of € -CL and 70% by weight of DMSO, i.e. 6 g-CL and 14 g DMSO. PRI me R, 4. The extraction is carried out as in example 1, but 20 g of the solvent contains 10% by weight of N-SCL (2 g) and 90 weight. % DMSO (13 g PRI me R 5. Extraction is carried out as in example 1, but 20 g of solvent contain 20% by weight of W-SCL (4 g) and 80% by weight of DMSO (16 g). Example 6 The extraction is carried out as in Example 1, but 20 g of the solvent contains 30% by weight of N-μL and 70% by weight of DMSO, i.e. 6 gY-MCL and 14 g of DMSO. The table shows the results of extraction according to examples 1-6 , as well as data on the extraction of a known device. The process is carried out at lower temperatures of 40 ° C., instead of. The most optimal composition is a mixed solvent containing 20 wt.% or (H-MKL) + 80 wt.% DMSO, because such a ra the solvent improves the selectivity of the process by about 1.8 times while simultaneously increasing the degree of extraction of the target component. The table also shows the results of one-stage extraction suggesting "lm solvent, catalytic reforming, 62-10 C, containing 32.3 wt.% aromatic hydrocarbons, including benzene - 10.7 wt.%, | goluol - 20.1 wt.%, xylenes, 1, 5 wt.%. Analysis of tabular data shows that the use of the proposed solvent allows to significantly improve the performance of a known method got it Yeni aromatic hydrocarbons. Namely, the solvent ratio to the raw material decreases by 3-4 times, the degree of extraction of the target product increases, the separation selectivity improves 1.7 times. 778946 Claims of Invention Aromatic hydrocarbons and their mixtures with non-aromatic by solvent extraction with a selective solvent based on caprolactam are also distinguished by the fact that, in order to increase the process efficiency, E-caprolactam or N-methylcaprolactam is used containing 7090 wt.% dimethylsulfoxane. Sources of information taken into account during the examination 1. A. Sulimov. Production of aromatic hydrocarbons and petroleum. M., Himi, 1975. 2. Patent of the USSR 464126, cl. C 07 S 7/10, 1975 (prototype).