Removal of glycols from a polyalkylene glycol dialkyl ether solution
AssigneeExxon Research & Engineering Co.
InventorsRalph G. Wolfe, Dennis P. Maloney, Robert E. Steele, Constantine Tsonopoulos, Eugene R. Thomas
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Abstract
The removal of a glycol contaminant from a mixture of polyalkylene glycol dialkyl ethers is achieved using a dual solvent extraction process. The process is particularly applicable to removing glycols which accumulate in recirculating solutions of polyalkylene glycol dialkyl ethers used for the absorption of acid gases from feedstocks such as natural gas, synthetic natural gas, refinery gas, and ammonia synthesis gas.
Claims26
A process for the purification of a solution comprising a polyalkylene glycol dialkyl ether or mixtures thereof which comprises:
- (1) contacting in an extraction zone a glycol contaminated polyalkylene glycol dialkyl ether solution with a solvent system comprising an organic solvent and an aqueous solvent;
- (2) dividing the contents of the extraction zone into two phases, a first phase relatively rich in both said organic solvent and said polyalkylene glycol dialkyl ether solution and a second phase relatively rich in said aqueous solvent and said glycol;
- and
- (3) separating said first phase into two streams:
- a first stream relatively rich in organic solvent for recycle to said extraction zone and a second stream relatively rich in polyalkylene glycol dialkyl ether and, with respect to the feed, depleted in glycols.
The process of claim wherein the organic solvent is a compound or mixture of compounds having a solubility parameter ranging from about 6.8 to 9.7.
The process of claim wherein the glycol is selected from the group consisting of triethylene glycol, diethylene glycol, and tetraethylene glycol and mixtures thereof.
The process of claim wherein the glycol content in the contaminated polyalkylene glycol dialkyl ether solution feed is about 3 to about 35 weight percent.
A process for the purification of a solution comprising a polyethylene glycol dimethyl ether or mixtures thereof which comprises:
- (1) contacting in an extraction zone a glycol contaminated solution comprising polyethylene glycol dimethyl ethers with a solvent system comprising an aqueous solvent and an organic solvent selected from the group consisting of compounds having a solubility parameter between about 8 and 9.4 and a boiling point between about 100.degree. and 400.degree. F.;
- (2) dividing the contents of the extraction zone into two phases, a first phase relatively rich in both said organic solvent and said polyethylene glycol dimethyl ether solution and a second phase relatively rich in said aqueous solvent and said glycol;
- and
- (3) separating said first phase into two streams:
- a first stream relatively rich in organic solvent for recycle to said extraction zone and a second stream relatively rich in polyethylene glycol dimethyl ethers.
A process for the purification of solution comprising a polyalkylene glycol dialkyl ether or mixtures thereof which comprises:
- (1) contacting in an extraction zone a glycol contaminated polyalkylene glycol dialkyl ether feed solution with a solvent system comprising an organic solvent and an aqueous solvent;
- (2) dividing the contents of the extraction zone into two phases, a first phase relatively rich in both said organic solvent and said polyalkylene glycol dialkyl ether solution and a second phase relatively rich in said aqueous solvent and said glycol;
- (3) separating in a distillation zone said first phase into two streams:
- a first stream relatively rich in organic solvent for recycle to said extraction zone and a second stream relatively rich in polyalkylene glycol dialkyl ether;
- (4) separating said second phase into two streams:
- a relatively glycol rich stream which is purged from further use in said extraction zone and a relatively glycol depleted aqueous stream form recycle to the extraction zone;
- and
- (5) purifying in a stripping zone the polyalkylene glycol dialkyl ether by contacting the same with a stripping gas to absorb therefrom remaining organic solvent.
Dependencies are inferred from the claim text.