Process for preparing ethylene glycol

Patent metadata

Field	Value
Publication number	US-10807929-B2
Application number	US-201916399153-A
Country	US
Kind code	B2
Filing date	Apr 30, 2019
Priority date	Apr 30, 2018
Publication date	Oct 20, 2020
Grant date	Oct 20, 2020

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.

First claim

We claim:

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 equal proportion of the aqueous ethylene oxide feed stream with the water stream to form a first feedstream containing ethylene oxide and water;
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 ethylene oxide and water contained in the first feedstream in the presence of a first ion exchange resin catalyst in the first adiabatic reactor to 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 first inter-stage heat-exchanger located downstream of the first adiabatic reactor to a hydration temperature;
combining the second equal proportion of the aqueous ethylene oxide feed stream and the cooled first reactor effluent 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 hydration temperature; and
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 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 wherein the first adiabatic reactor has an outlet temperature that is higher than the first inlet temperature, and the second adiabatic reactor has an outlet temperature that is higher than the second inlet temperature of the first adiabatic reactor, and wherein the water stream is heated, prior to combining with the first equal proportion of the aqueous ethylene oxide feed, by a non inter-stage heat-exchanger located upstream from the first adiabatic reactor, wherein the non inter-stage heat-exchanger differs from the first inter-stage heat exchanger.

2. The liquid phase process according to claim 1 , wherein each of the first inlet temperature and the second inlet temperature is from about 50° C. to about 90° C.

3. The liquid phase process according to claim 1 , wherein each of the first outlet temperature and the second outlet temperature is from 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 second inter-stage heat-exchanger located downstream of the second adiabatic reactor;
combining the third equal 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 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 third inter-stage heat-exchanger located downstream of the third adiabatic reactor;
combining the fourth equal 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 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 flash drum to form an 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 % ethylene oxide; and (2) a lean cycle water solution in a 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 present in both the first adiabatic reactor and the second adiabatic reactor is a type I strongly basic anion exchange resin.

11. The liquid phase process according to claim 1 , wherein the ion exchange resin catalyst present in both the first adiabatic reactor and the second adiabatic reactor has a bicarbonate or monocitrate functional group.

12. The liquid phase process according to claim 1 , wherein the ion exchange resin catalyst present in both the first adiabatic reactor and the second adiabatic reactor 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.

Assignees

• Scient Design Co

Inventors

• Chan Chun Chau
• Yamada Eunice
• Billig Barry Jay
• Mcgovern Shaun

Classifications

• C07C31/202

  Ethylene glycol · CPC title

• C07C29/106 Primary

  of oxiranes · CPC title

• B01J2219/0072

  Organic compounds · CPC title

• B01J2219/00306

  Reactor vessels in a multiple arrangement · CPC title

• B01J2219/0015

  by thermal insulation means · CPC title