Process for the separation of glycol from an electrolyte-containing aqueous solution

• US 4,427,507 A
• Filed: 10/06/1982
• Issued: 01/24/1984
• Est. Priority Date: 03/22/1982
• Status: Expired due to Term

• Current Assignee: Shell Oil Company (Shell Plc)
• Original Assignee: Shell Oil Company (Shell Plc)
• Inventors: Pedley, Jeffrey B., van Aken, Andreas B., van Diepen, Petrus B. J.
• Primary Examiner(s): Niebling, John F.
• Application Number:
  US06/433,065
• Time in Patent Office: 475 Days
• Field of Search: 204/151, 204/180 P
• US Class Current: 204/522
• CPC Class Codes: B01D 61/44 Ion-selective electrodialysis
• CPC Class Codes: C07C 2/08 Catalytic processes
• CPC Class Codes: C07C 29/74 Separation; Purification; Use of additives, e.g. for stabilisation
• CPC Class Codes: C07C 29/76 by physical treatment
• CPC Class Codes: C07C 31/20 Dihydroxylic alcohols
• CPC Class Codes: C07C 31/202 Ethylene glycol
• CPC Class Codes: C07C 31/207 1,4-Butanediol; 1,3-Butanediol; 1,2-Butanediol; 2,3-Butanediol
• CPC Class Codes: C07C 7/11 by absorption, i.e. purification or separation of gaseous hydrocarbons with the aid of liquids
• CPC Class Codes: C07C 9/04 Methane production by treatment of sewage C02F11/04; natural gas, synthetic natural gas C10L3/06

Abstract

A process is disclosed for separating glycols from an electrolyte-containing aqueous solution comprises electrodialyzing said solution to increase the glycol to electrolyte content and subsequently removing a substantial part of the water.

Claims

1. In a process for recovering a glycol having two OH groups from an aqueous glycol electrolyte-containing solution comprising introducing said aqueous glycol solution as feed into the depletion compartment of an electrodialytic cell, introducing an electrolyte solution into an anode compartment and a cathode compartment of said electrodialytic cell, said cathode compartment being separated from said depletion compartment by a cation selective membrane, said depletion compartment being separated from the anode compartment by an anion selective membrane, passing a current through said electrodialytic cell at a direct voltage in the range between 0 and 4.5 volt and raising the mole ratio of glycol to electrolyte in said aqueous glycol soluton in said depletion compartment, and subsequently removing a substantial part of the water from said aqueous glycol solution, the improvement comprising that in the electrodialysis cell membrane pairs are used the sum of whose electroosmotic fluxes is less than 300 g/F.

2. A process as in claim 1, wherein the current is passed at a direct voltage in the range between 1.5 to about 2.5 Volt.

3. A process as in claim 1 wherein said feed is salt-containing waste water containing glycols formed by hydrolysis of ethylene oxide.

4. A process as in claim 1 wherein said feed is glycol-containing saline water from a process for drying natural gas.

5. A process as in claim 1 wherein said feed is salt-contaminated butanediol originating from a process for the preparation of C₁₀ -C₂₀ alpha-olefins by way of oligomerization of ethene using a catalyst dissolved in butanediol.