RECIRCULATING PROCESS FOR PREPARING ETHYLENE GLYCOL

• US 20190330133A1
• Filed: 04/30/2019
• Published: 10/31/2019
• Est. Priority Date: 04/30/2018
• Status: Active Grant

• Current Assignee: Scientific Design Company, Inc. (Clariant AG)
• Original Assignee: Scientific Design Company, Inc. (Clariant AG)
• Inventors: McGovern, Shaun, Yamada, Eunice, Billig, Barry Jay, Chan, Chun Chau
• Granted Patent: US 10,807,928 B2
• Time in Patent Office: Days
• CPC Class Codes: C07C 29/106 of oxiranes
• CPC Class Codes: C07C 29/152 characterised by the reactor used
• CPC Class Codes: C07C 29/153 characterised by the catalyst used
• CPC Class Codes: C07C 31/202 Ethylene glycol
• CPC Class Codes: Y02P 20/52 using catalysts, e.g. selective catalysts

Abstract

An improved catalytic hydration process that includes a catalytic hydration reaction section containing adiabatic reactors with ion exchange resin catalyst and which maintains low resin swelling and excellent selectivity while also reducing process complexity and increasing versatility.

Claims

1. A liquid phase process for the production of ethylene glycol comprising:

providing an ethylene oxide-water solution containing ethylene oxide and water;

combining a catalytic hydration feedstream with a recirculation split stream to form a first reactor inlet stream;

supplying the first reactor inlet stream to an inlet of a first adiabatic reactor, the inlet of the first adiabatic reactor being at a first inlet temperature;

reacting the ethylene oxide and water in the presence of a first ion exchange resin catalyst in the first adiabatic reactor to thereby produce an effluent stream containing water, ethylene glycol, and unreacted ethylene oxide;

further combining the effluent stream with a recirculation supply stream to form a combined stream containing water, ethylene glycol and unreacted ethylene oxide;

supplying the combined stream to an inlet of a second adiabatic reactor, the inlet of the second adiabatic reactor being at a second inlet temperature;

reacting ethylene oxide and water in the presence of a second ion exchange resin catalyst in the second adiabatic reactor to thereby produce a second reactor effluent stream containing water, ethylene glycol, and unreacted ethylene oxide;

compressing the second reactor effluent stream;

dividing the second reactor effluent stream into a recirculation stream and a forward stream;

dividing the recirculation stream into a split recirculation stream and the supply recirculation stream;

supplying the forward stream as the pipe reactor feedstream to a non-catalytic pipe reactor to produce a product stream wherein the total concentration of DEG, TEG and higher glycols in the product stream is greater than the total concentration of DEG, TEG and higher glycols in the forward stream.

2. The liquid phase process according to claim 1, wherein the inlet temperature of the pipe non-catalytic pipe reactor is from about 130°

C. to about 160°

C.

3. The liquid phase process according to claim 1, wherein the inlet temperature is about 50°

C. to about 90°

C.

4. The liquid phase process according to claim 1, wherein the outlet temperature is about 90°

C. to about 120°

C.

5. The liquid phase process according to claim 1, wherein a molar ratio of water:

ethylene oxide in the first feedstream is about 40;

1 to about 10;

1.

6. The liquid phase process according to claim 5, wherein said molar ratio of water:

ethylene oxide in the first feedstream is about 30;

1 to about 20;

1.

7. The liquid phase process according to claim 1, conducted continuously.

8. The liquid phase process according to claim 1, wherein a total molar ratio of water:

ethylene oxide in the water stream and the aqueous ethylene oxide feedstream when added together is about 5;

1 to about 15;

1.

9. The liquid phase process according to claim 1, wherein a total molar ratio of water:

ethylene oxide in the water stream and the aqueous ethylene oxide feedstream when added together is about 7;

1 to about 12;

1.

10. The liquid phase process according to claim 1, wherein the concentration of ethylene oxide in the forward stream is no greater than about 1 mol %.

11. The liquid phase process according to claim 1, wherein the conversion percentage of ethylene oxide to monoethyelene glycol in the first adiabatic reactor is at least about 50%.

12. The liquid phase process according to claim 1, wherein the aqueous ethylene oxide feed stream is prepared according to the following steps:

providing a rich cycle water stream containing ethylene oxide, methane, ethylene, and other dissolved light gases;

separating, in a flash drum, a light gas solute vapor from the rich cycle water stream;

directing upwardly the light gas solute vapor through an opening in the flash drum allowing fluid communication to an absorber affixed to the to the top surface of the flash drum to form the absorber vapor overhead;

pumping and heating the rich cycle water from a liquid bottoms of the flash drum to a stripper; and

separating into;

(1) an enriched overhead stripper liquid stream comprising at least about 40 mol %, and (2) a lean cycle water solution in the stripper bottoms containing about 5 to about 50 molar ppm ethylene oxide in the stripper bottoms.

13. The liquid phase process according to claim 12, wherein said enriched overhead stripper liquid stream comprises at least about 50 mol % ethylene oxide.

14. The liquid phase process according to claim 1, wherein the ion exchange resin catalyst is a type I strongly basic anion exchange resin.

15. The liquid phase process according to claim 1, wherein the ion exchange resin catalyst has a bicarbonate or monocitrate functional group.

16. The liquid phase process according to claim 1, wherein the ion exchange resin catalyst includes a linking group.

17. The liquid phase process according to claim 1, wherein the first and second feedstreams are substantially free of carbon dioxide.