The regeneration process of the return of the solvent process of synthetic rubbers

 

(57) Abstract:

The invention relates to the production of synthetic rubbers obtained solution polymerization, in particular to the regeneration of the return of the solvent from the stage of selection of rubbers. The objective of the invention is the treatment of recurrent solvent in the production of synthetic rubber from trace contaminants. To solve this problem is proposed a method of regeneration of a reflexive solvent process of synthetic rubbers obtained from stage water degassing polymer process of synthetic rubber, including separation from condensate water layer and cleanup of hydrocarbon layer containing the reflexive solvent by aqueous-alkaline cleaning, Stripping him of volatile hydrocarbons, drying and distillation return solvent for separation of heavy hydrocarbons, and then return the solvent serves on stage hydrotreatment. Perhaps the Hydrotreating carried out on the catalytic hydrogenation of unsaturated hydrocarbons. Perhaps the distillate distillation of the cubic product of the column separation of heavy hydrocarbons from the return of solvent to submit at stage g of the obtained solution polymerization, in particular to the regeneration of the return of the solvent from the stage of selection of rubbers.

There is a method of regeneration of the hydrocarbon solvent from the return of the solvent in the manufacture of synthetic rubber (U.S. Pat. RF N 2039756, MKI C 08 C 2/06, publ. 20.07.95. Bull. N 20). The method includes sucks solvent from suspended moisture, azeotropic distillation dehydration, distillation of the dried solvent from the high-boiling components, rectification of the bottom liquid in a two-column scheme. But the scheme does not clear solvent to the required degree of purity and impurity unsaturated hydrocarbons contained in the return solvent, purified according to this scheme, prevent stereoregular polymerization.

Closest to the claimed method according to technical essence is a regeneration process of the return of the solvent in the manufacture of synthetic rubbers, as described in the book edited by P. A. Kirpichnikov (Album technological schemes the main production of the synthetic rubber industry /P. Kirpichnikov, A. and others // L.: Chemistry, 1986, S. 161-163.). The method involves the condensation of vapors from the stage degassing the mixture with a 10% solution of alkali diaphragm in the mixer in RA is th. The washed solvent is fed to a distillation to remove volatile and heavy components, and then to azeotropic dehydration and drying of the zeolite, and then fed to the polymerization. But the scheme does not clear the solvent to the desired degree of purity, and impurities unsaturated and aromatic hydrocarbons contained in the return solvent, purified according to this scheme, prevent stereoregular polymerization.

The objective of the invention is the treatment of recurrent solvent in the production of synthetic rubber from the concentration of unsaturated and aromatic hydrocarbons.

To solve this problem is proposed a method of regeneration of a reflexive solvent process of synthetic rubbers obtained by the condensation of the solvent vapor from the stage of water degassing of the polymer, including separation from condensate water layer and cleanup of hydrocarbon layer containing the reflexive solvent by aqueous-alkaline cleaning, Stripping from the return of the solvent volatile hydrocarbons, rectification return of the solvent from the heavy hydrocarbons, drying, and drying is carried out after the distillation from vospetogo solvent from the heavy hydrocarbons, this rectification is subjected cubic liquid from the stage of drying, and then return the solvent serves on stage hydrotreatment. Perhaps the Hydrotreating carried out on the catalytic hydrogenation of unsaturated hydrocarbons. Possibly in addition carry out the rectification of the cubic product from stage rectification bottom liquid from the stage of drying to separate the return of the solvent from the heavy hydrocarbons, distillate rectification above the cubic product also serves on stage hydrotreatment.

The proposed method allows you to clean return the solvent to the desired degree of purity in the production of almost all types of rubbers, such as CDS, qualified electronic signature certificate, SKEPT, SKI and so on, including for the preparation of the catalytic complex. Water-alkaline washing is conducted in a conventional way, for example 10% alkali solution and then desalted water. Dewatering if necessary, may contain multiple stages. For example, sludge from water and azeotropic dehydration or sludge from moisture, azeotropic drying and dehydration of the zeolite and so on. Rectification can be carried out in one or more distillation columns. As hydrogenation catalysts can be used in the th Hydrotreating in one or more areas of hydrogenation.

The proposed method of return regeneration of the solvent allows to clean not only return the solvent from the trace to the polymerization degree of purity, but also part of the spent solvent, which was discussed previously in the waste. Cleaning returnable solvent by hydrogenation in the process of regeneration by us were not found in literature, which indicates compliance with the criteria of patentability.

All of the above is illustrated by the following examples.

Example 1.

Return hydrocarbon solvent I in the production of synthetic rubber, SKEPT using as the third monomer is Dicyclopentadiene (DCPD) and having the following composition, wt.%:

The amount of hydrocarbon, C5- 0,43

Isohexane - 51,17

Normal hexane - 46,50

Cyclohexane - 0,10

Toluene - 0,76

Benzene - 0,20

The cyclopentadiene - 0,08

The amount of C7and above - 0,75

Moisture - 0,01

Bromine number, g Br/100 ml - 0,035

(the content of unsaturated hydrocarbons)

from the Department of degassing comes in 20 t/h to the node from suspended sediment moisture 1, where does also wrap IX column azeotropic dehydration 4. After the return sludge solvent II the settlement of the Oh water. The washed solvent IV enters the distillation column 3, where the separation of light hydrocarbons VII. Waste liquid VI column 3 is fed to the azeotropic dehydration column 4. The temperature of the top of the column azeotropic dehydration 71-75oC, the temperature of the cube in an average of 82oC, the pressure of the top 0.5-0.6 MPa, Cuba 0.7 to 0.8 MPa. Top zipper columns 4, a pair azeotropic mixture of solvent-water" IX arrives at the node from suspended sediment moisture 1. Cube VIII liquid column azeotropic dehydration 4 of 20 t/h is fed to the rectification column 5 for the separation of heavy hydrocarbons.

After separation of heavy hydrocarbons return solvent X having the following composition, wt.%:

The amount of hydrocarbon, C5- 0,51

Isohexane - 50,33

Normal hexane - 48,71

Cyclohexane - 0,09

C7+- 0,16

Benzene - 0,20

fed to the Hydrotreating reactor of 6 filled with a heterogeneous catalyst "Nickel on kieselguhr". The process is carried out at a temperature of 50oC, a pressure of 0.34 MPa, the consumption of raw materials 2.8 t/h, the flow rate of hydrogen 25 m3/H. Reversionary solvent before and after Hydrotreating was analyzed by gas chromatography using chromatogram substances by the method of column chromatography. The indicator "bromine number was determined by standard bromate-bromanil method. After Hydrotreating, the content of trace contaminants in regenerated return the solvent XIV is:

Aromatic hydrocarbons, wt.% - 0,001

Bromine number, g Br/100 ml - 0,0006

JRS, wt.% - 0,0025

The results of the experiment are shown in the table.

Example 2.

The experience is conducted under the conditions of example 1 but at a temperature Hydrotreating 120oC. the Results are shown in the table.

Example 3.

The experience is conducted under the conditions of example 1, but as the third monomer used ethylidenenorbornene (ENB). The results of the experiment are shown in the table.

Example 4.

The experience is conducted under the conditions of example 2, but as the third monomer used ethylidenenorbornene. The results of the experiment are shown in the table.

Example 5.

The experience is conducted under the conditions of example 1, but regenerate return the solvent to the production of polybutadiene synthetic rubber (SKD). The results of the experiment are shown in the table.

Example 6.

The experience is conducted under the conditions of example 2, but regenerate return the solvent to the production of polybutadiene manufactured under the conditions of example 1, but as a catalyst for Hydrotreating using a platinum catalyst. The results of the experiment are shown in the table.

Example 8.

The experience is conducted under the conditions of example 2, but as a catalyst for Hydrotreating using a platinum catalyst. The results of the experiment are shown in the table.

Example 9.

The experience is conducted under the conditions of example 1, but the cube column 5 separation of heavy hydrocarbons XI (spent solvent) is fed to the rectification column 5A and the distillate XII of this column then sent to Hydrotreating. The Hydrotreating is carried out at 70oC and a pressure of 0.34 MPa, at a flow rate of the raw material of 2.8 t/h, hydrogen 30 m3/H. the Results of the experiment are shown in the table.

Example 10.

The experience is conducted under the conditions of example 9, but the Hydrotreating is carried out at 140oC and a pressure of 0.34 MPa, at a flow rate of the raw material of 2.8 t/h, hydrogen 30 m3/H. the Results of the experiment are shown in the table.

Example 11.

The experience is conducted under the conditions of example 9, but as the return of the solvent used CBM product column separation taglocity hydrocarbons (spent solvent) with the production of polybutadiene synthetic rubber (SKD), the distillate of the distillation EIA 2.8 t/h, hydrogen 30 m3/H. the Results of the experiment are shown in the table.

Example 12.

The experience is conducted under the conditions of example 11, but the Hydrotreating is carried out at 140oC and a pressure of 0.34 MPa, at a flow rate of the raw material of 2.8 t/h, hydrogen 30 m3/H. the Results of the experiment are shown in the table.

Example 13.

The experience is conducted under the conditions of example 9, but the Hydrotreating is conducted on the platinum catalyst FE-62. The results of the experiment are shown in the table.

Example 14.

The experience is conducted under the conditions of example 10, but the Hydrotreating is conducted on the platinum catalyst FE-62. The results of the experiment are shown in the table.

As can be seen from the presented examples, the return regeneration of the solvent, using the secondary stage Hydrotreating can improve the cleaning solvent from the aromatic and unsaturated hydrocarbons and to regenerate a portion of the spent solvent, previously directed to waste.

1. The regeneration process of the return of the solvent process of synthetic rubbers obtained by the condensation of the solvent vapor from the stage of water degassing of the polymer, including separation from condensate water layer and cleanup of hydrocarbon layer, sterlitech hydrocarbons, rectification return of the solvent from the heavy hydrocarbons, drying, characterized in that the drying is carried out after the distillation, from the return of the solvent, volatile hydrocarbons, and then carry out the above rectification return of the solvent from the heavy hydrocarbons, is subjected to rectification cubic liquid from the stage of drying, and then return the solvent serves on stage hydrotreatment.

2. The method according to p. 1, wherein the hydrotreatment is performed on the catalytic hydrogenation of unsaturated hydrocarbons.

3. The method according to PP.1 and 2, characterized in that it further carry out the rectification of the cubic product from stage rectification bottom liquid from the stage of drying to separate the return of the solvent from the heavy hydrocarbons, distillate rectification above the cubic product also serves on stage hydrotreatment.

 

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