PROCESS FOR THE PRODUCTION OF A POLYMER USING A COMPOUND COMPRISING AT LEAST 2 UNSATURATED CARBON-CARBON BONDS

Abstract

The present invention relates to a process for the production of a polymer using a compound comprising at least 2 unsaturated carbon-carbon bonds, wherein the process comprises a polymerisation section and a purification section, wherein the product from the polymerisation section is subjected in the purification section to a sequence of purification steps comprising: removal of the vapour phase from the product from the polymerisation section by means of flash separation to obtain a first vapour phase and a polymerisation product; subjecting the first vapour phase to a compression and condensation treatment to obtain a second vapour phase and a condensed monomer phase; wherein the purification steps are conducted in this order. Such process allows for the optimal utilisation of raw materials in the polymerisation process.

Claims

1. A process for the production of a polymer using a compound comprising at least 2 unsaturated carbon-carbon bonds, wherein the process comprises a polymerisation section and a purification section, wherein the product from the polymerisation section is subjected in the purification section to a sequence of purification steps comprising: removing the vapour phase from the product from the polymerisation section by means of flash separation to obtain a first vapour phase and a polymerisation product; and subjecting the first vapour phase to a compression and condensation treatment to obtain a second vapour phase and a condensed monomer phase; wherein the purification steps are conducted in this order.

2. The process according to claim 1, wherein the compound comprising at least 2 unsaturated carbon-carbon bonds is selected from a butadiene, a pentadiene, a hexadiene, a heptadiene, an octadiene, or combinations thereof.

3. The process according to claim 1, wherein the compound comprising at least 2 unsaturated carbon-carbon bonds is 1,3-butadiene.

4. The process according to claim 1, wherein the compression step comprises compression of the first vapor phase to a pressure of 400 kPa.

5. The process according to claim 1, wherein the compression and condensation treatment is performed using a positive displacement compressor.

6. The process according to claim 1, wherein the condensed monomer phase is recycled back to the polymerisation section.

7. The process according to claim 1 wherein the second vapour phase is further subjected to an absorption step and a stripping step to obtain a second monomer phase.

8. The process according to claim 7, wherein the absorption step is conducted at a pressure of 300 kPa and 550 kPa.

9. The process according to claim 7, wherein the absorption step is performed in a vertically positioned packed column separator having an inlet positioned above the packed section of the column where a mineral oil having a temperature of 45-55 C. is fed to the column, an inlet where the second vapour phase is entered into the column, and an outlet at the bottom where the mineral oil comprising the absorbed compound comprising at least 2 unsaturated carbon-carbon bonds is removed from the column.

10. The process according to claim 7, wherein the absorption step comprises absorption of the compound comprising at least 2 unsaturated carbon-carbon bonds in a mineral oil, and wherein the stripping step comprises separation of the compound comprising at least 2 unsaturated carbon-carbon bonds from the mineral oil.

11. The process according to claim 9, wherein the mineral oil is a synthetic isoparaffinic hydrocarbon having an aromatic content of 20 wt % and a flash point of 40 C. as determined in accordance with ISO 1523 (2002).

12. The process according to claim 7, wherein the stripping step is conducted at a pressure of 600 kPa and at a temperature of 45 and 70 C.

13. The process according to claim 7, wherein the stripping step is performed in a vertically positioned packed column separator equipped with a reboiler at the bottom of the column.

14. The process according to claim 7, wherein the second monomer phase is recycled back to the polymerisation section.

15. The process according to claim 1, wherein 95 wt % of the monomer comprising at least 2 unsaturated carbon-carbon bonds that is introduced to the polymerisation section is converted into the polymerisation product.

Description

[0050] FIG. 1 presents the process according to the invention comprising a polymerisation section represented by unit I and a purification section represented by units II, III and IV, wherein unit II is a flash separation vessel, unit III is a compressor and unit IV is a condenser, from which a condensed monomer phase F is obtained that is fed back to the polymerisation section.

[0051] FIG. 2 presents the process according the invention of the embodiment of FIG. 1 further comprising subjecting the second vapour phase G to an absorption step represented by unit V and a stripping step represented by unit VI to obtain a second monomer phase that is fed back to the polymerisation section.

[0052] In FIG. 1: [0053] material stream A represents the reaction mixture comprising a compound comprising at least 2 unsaturated carbon-carbon bonds; [0054] unit I represents the polymerisation section; [0055] material stream B represents the product from the polymerisation section; [0056] units II, III and IV represent the purification section, in which unit II represents the flash separation vessel; [0057] material stream C represents the polymerisation product separated by the flash separation; [0058] material stream D represents the first vapour phase obtained from the flash separation vessel; [0059] unit III represents the compressor; [0060] material stream E represents the compressed first vapour phase; [0061] unit IV represents the condenser; [0062] material stream F represents the condensed monomer phase which is fed back to the polymerisation section; and [0063] material stream G represents the second vapour phase.

[0064] In a more particular embodiment, the process according to the present invention further comprises an absorption step and a stripping step. FIG. 2 presents a disclosure of an embodiment of the invention comprising such absorption step and stripping step, wherein:

[0065] unit V represents the absorption unit;

[0066] material stream H represents the absorbing medium;

[0067] material stream J represents the absorbing medium comprising the absorbed compounds;

[0068] unit VI represents the stripping unit;

[0069] material stream K represents a waste material stream; and

[0070] material stream L represents the second monomer phase which is fed back to the polymerisation section.

[0071] The present invention will now be illustrated by the following non-limiting example.

[0072] In a polymerisation section I comprising polymerisation reactor, a reaction mixture A comprising 16913 kg 1,3-butadiene and 24000 kg water were reacted in a batch operation to obtain a material stream B comprising 16045 kg polybutadiene as polymerisation product and 868 kg 1,3-butadiene. The material stream B was fed to a flash separation vessel II at a temperature of 63 C. and a pressure of 348 kPa. From the flash separation vessel, a material stream C comprising 16045 kg of the polymerisation product and 43 kg 1,3-butadiene at a temperature of 61 C. and a pressure of 376 kPa was obtained, and a material stream D representing the first vapour phase, comprising 825 kg 1,3-butadiene and 16 kg water, at a temperature of 53 C. and a pressure of 121 kPa was obtained.

[0073] The material stream D was fed to a compressor III at a pressure of 121 kPa and a temperature of 53 C. at a rate of 2162 kg 1,3-butadiene and 43 kg water. The material stream E exited the compressor at a pressure of 445 kPa and a temperature of 20 C., and entered a condenser IV at these pressure and temperature conditions, at a rate of 2162 kg 1,3-butadiene and 43 kg water. A material stream F was obtained from the condenser at a pressure of 575 kPa and a temperature of 20 C. comprising 1788 kg/h of recovered 1,3-butadiene which may be recycled to be used in polymerisation section I, and a material stream G representing a second vapour phase, at a temperature of 20 C. and a pressure of 445 kPa, comprising 374 kg/h of 1,3-butadiene and 43 kg/h of water.

[0074] The use of the process according to this example resulted in a reduction of the 1,3-butadiene loss in waste streams to 0.9 wt % of the quantity of 1,3-butadiene that was fed to the polymerisation section, compared to 5.1 wt % without the use of a condenser.

[0075] In a further example, the material stream G was further subjected to an absorbing and stripping step. To an absorber unit V, the second vapour phase G was supplied at a temperature of 20 C. and a pressure of 445 kPa at a rate of 374 kg/h of 1,3-butadiene and 43 kg/h of water, and was brought into contact with a quantity of a mineral oil H. The stream J exiting the absorber unit was supplied to a stripper unit VI resulting in a waste stream K comprising 8 kg/h of 1,3-butadiene and 43 kg/h of water, and a material stream L comprising 366 kg/h 1,3-butadiene, which may be recycled to be used in polymerisation section I.

[0076] The use of the process according to this example resulted in a reduction of the 1,3-butadiene loss in waste streams to 0.02 wt % of the quantity of 1,3-butadiene that was fed to the polymerisation section.