PROCESS FOR PREPARING ETHYLENE GLYCOL

• US 20190330134A1
• 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: Chan, Chun Chau, Yamada, Eunice, Billig, Barry Jay, McGovern, Shaun
• Granted Patent: US 10,807,929 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 a water stream and an aqueous ethylene oxide feed stream;

dividing the aqueous ethylene oxide feed stream into at least a first equal proportion and a second equal proportion;

combining the first proportion and the water stream to form a first feedstream;

feeding the first feedstream into an inlet of a first adiabatic reactor, the inlet of the first adiabatic reactor being at an 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 a first reactor effluent stream containing water, ethylene glycol, and unreacted ethylene oxide;

withdrawing the first reactor effluent stream from an outlet of the first adiabatic reactor;

cooling the first reactor effluent stream through a heat-exchanger located downstream of the first adiabatic reactor to the hydration temperature; and

combining the second proportion and the cooled product stream to form a second feedstream;

conveying the second feedstream to an inlet of a second adiabatic reactor, the inlet of the second adiabatic reactor being at the hydrolysis temperature;

reacting ethylene oxide and water contained in the second feedstream 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,

wherein the first adiabatic reactor and the second adiabatic reactor each contain an ion exchange resin catalyst in a fixed catalyst bed and the outlet temperature is higher than the inlet temperature.

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

C. to about 90°

C.

3. The liquid phase process according to claim 1, wherein the outlet temperature is about 85°

C. to about 120°

C.

4. 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.

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

6. 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 feed stream when added together is about 5;

1 to about 15;

1.

7. The liquid phase process according to claim 1, wherein the aqueous ethylene oxide feed stream is further divided into a third equal proportion and a fourth equal proportion and further comprises the following steps:

withdrawing the second reactor effluent stream from an outlet of the second adiabatic reactor;

cooling the second reactor effluent stream through a heat-exchanger located downstream of the second adiabatic reactor;

combining the third proportion and the cooled second reactor effluent stream to form a third feedstream;

conveying the third feedstream to an inlet of a third adiabatic reactor;

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

withdrawing the third reactor effluent stream from an outlet of the third adiabatic reactor;

cooling the third reactor effluent stream through a heat-exchanger located downstream of the third adiabatic reactor;

combining the fourth proportion and the cooled third reactor effluent stream to form a fourth feedstream;

conveying the third feedstream to an inlet of a fourth adiabatic reactor; and

reacting ethylene oxide and water contained in the fourth feedstream in the presence of a fourth ion exchange resin catalyst bed in the fourth adiabatic reactor to thereby produce a fourth reactor effluent stream containing water, ethylene glycol, and unreacted ethylene oxide.

8. The liquid phase process according to claim 7, further comprising feeding the fourth reactor effluent stream to a non-catalytic reactor.

9. 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 %, preferably at least about 50 mol % ethylene oxide; and

(2) a lean cycle water solution in the stripper bottoms containing about 1 to about 50 molar ppm ethylene oxide in the stripper bottoms.

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

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

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

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

14. The liquid phase process according to claim 10, wherein the type I strongly basic anion exchange resin includes a quaternary ammonium stationary group.

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

ethylene oxide in the first feedstream is about 30;

1 to about 20;

1.

16. 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 feed stream when added together is about 7;

1 to about 12;

1.