Recirculating process for preparing ethylene glycol

Patent metadata

Field	Value
Publication number	US-10807928-B2
Application number	US-201916399108-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 an ethylene oxide-water solution stream containing ethylene oxide and water;
combining the ethylene oxide-water solution stream 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, wherein the first reactor inlet stream is cooled to the first inlet temperature, prior to being supplied to the inlet of the first adiabatic reactor, by a heat-exchanger that is located upstream from the first adiabatic reactor;
reacting the ethylene oxide and water contained in the first reactor inlet stream in the presence of a first ion exchange resin catalyst in the first adiabatic reactor to 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 contained in the combined stream 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;
compressing the second reactor effluent stream;
dividing the second reactor effluent stream into a recirculation supply stream and a forward stream;
dividing the recirculation stream into the split recirculation stream and the recirculation supply stream; and
supplying the forward stream to a non-catalytic pipe reactor to produce a product stream wherein the total concentration of diethylene glycol (DEG), triethylene glycol (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 non-catalytic pipe reactor has an inlet temperature from about 130° C. to about 160° C.

3. 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.

4. The liquid phase process according to claim 1 , wherein the first adiabatic reactor has a first outlet temperature and the second adiabatic reactor has a second outlet temperature, wherein each of the first outlet temperature and the second outlet temperature is from about 90° C. to about 120° C.

5. The liquid phase process according to claim 1 , wherein the first reactor inlet stream has a molar ratio of water:ethylene oxide of from 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 reactor inlet stream is from 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 ethylene oxide-water solution stream 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 ethylene oxide-water solution stream 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 a 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 ethylene oxide-water solution stream comprises a combination of an aqueous ethylene oxide feed stream and a water stream, 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 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 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 present in both the first adiabatic reactor and the second adiabatic reactor is a type I strongly basic anion exchange resin.

15. 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.

16. 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.

17. The liquid phase process according to claim 1 , wherein the first reactor inlet stream and the combined stream are substantially free of carbon dioxide.

Assignees

• Scient Design Co

Inventors

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

Classifications

• C07C31/202

  Ethylene glycol · CPC title

• C07C29/106 Primary

  of oxiranes · CPC title

• B01J2219/00452

  Means for the recovery of reactants or products · CPC title

• B01J2219/00306

  Reactor vessels in a multiple arrangement · CPC title

• B01J2219/0015

  by thermal insulation means · CPC title