System and process for producing glycols
A system and a method for producing ethylene glycol are disclosed. Alkylene oxide and water are flowed into a first reactor unit and subjecting the alkylene oxide and water, in the first reactor unit, to first reaction conditions such that an effluent of the first reactor unit comprises an alkylene glycol, unreacted alkylene oxide, and unreacted water. At least a portion of the unreacted alkylene oxide may be routed to a second reaction unit and subjected to reaction conditions sufficient to produce additional alkylene glycol, wherein the second reactor unit is a reactive distillation column.
1 . A method of producing alkylene glycol, the method comprising:
flowing a feed stream comprising alkylene oxide and water into a first reactor unit;
subjecting the alkylene oxide and water, in the first reactor unit, to first reaction conditions such that an effluent of the first reactor unit comprises an alkylene glycol, unreacted alkylene oxide, and unreacted water;
flowing at least a portion of the unreacted alkylene oxide and unreacted water to a second reactor unit; and
subjecting the unreacted alkylene oxide and unreacted water in the second reactor unit to second reaction conditions sufficient to produce additional alkylene glycol;
wherein the second reactor unit is a reactive distillation column and higher mono alkylene to di alkylene glycol ratio is produced even at lower water to alkylene oxide ratio; and wherein one or both of:
(i) the first reactor unit comprises a plug flow reactor adapted to provide the first reaction conditions therein; or
(ii) the first reactor has a reaction residence time of 0.5 to 8 minutes.
2 . The method of claim 1 , wherein the alkylene glycol is ethylene glycol and the alkylene oxide is ethylene oxide.
3 . The method of claim 2 , wherein the first reactor unit comprises a plug flow reactor adapted to provide the first reaction conditions therein.
4 . The method of claim 3 , further comprising:
flowing a stream of water to the reactive distillation column.
5 . The method of claim 4 , wherein the water enters the reactive distillation column at a temperature in a range of 125° C. to 150° C.
6 . The method of claim 3 , wherein the reactive distillation column is further adapted for reaction and distilling liquids and the method further comprises:
reactive distilling in the reactive distillation column, the effluent of the first reactor unit to produce (1) an overhead stream comprising unreacted water and unreacted ethylene oxide and (2) a bottoms stream comprising unreacted water and mono ethylene glycol; and
recycling at least a portion of the overhead stream back to the reactive distillation column as reflux.
7 . The method of claim 6 , wherein the bottoms stream further comprises diethylene glycol, and/or triethylene glycol.
8 . The method of claim 1 , wherein the first reactor has a reaction residence time of 0.5 to 8 minutes.
9 . The method of claim 8 , further comprising recovering at least a portion of ethylene oxide from the effluent of the first reactor unit for pure ethylene oxide production.
10 . The method of claim 2 , wherein the effluent of the first reactor unit further comprises diethylene glycol and/or triethylene glycol.
11 . The method of claim 2 , wherein the first reaction conditions and second reaction conditions are non-catalytic reaction conditions.
12 . The method of claim 2 , wherein the reaction conditions in the first reactor unit comprise: a reactor inlet temperature in a range of 120 to 160° C., a reaction pressure of 18 to 25 bar, and a residence time of 0.5 to 8.0 minutes.
13 . A method of producing an alkylene glycol, the method comprising:
flowing a feed stream comprising alkylene oxide and water into a first reactor;
subjecting the feed stream and water in the first reactor to reaction conditions sufficient to produce alkylene glycol such that a first effluent stream of the first reactor comprises alkylene glycol, unreacted alkylene oxide, and unreacted water;
separating, in a separation unit, the first effluent stream to produce a first stream comprising primarily unreacted water and unreacted alkylene oxide, collectively, and a second stream comprising primarily unreacted water, and alkylene mono glycol, unreacted alkylene oxide, collectively;
flowing the second stream into a second reactor unit; and
subjecting the second stream, in the second reactor unit, to the second reaction conditions, wherein one or both of:
i) the separating of first effluent stream to produce the first stream and the second stream is performed at an overhead boiling temperature range of 150 to 180° C. and a pressure range of 6 to 20 bar; or
ii) the second reaction conditions in the second reactor unit comprise a reactor inlet temperature in a range of 160 to 220° C. and a reaction pressure of 10 to 20 bar.
14 . The method of claim 13 , wherein the second reaction conditions in the second reactor unit are non-catalytic reaction conditions.
15 . The method of claim 13 , wherein the alkylene glycol comprises ethylene glycol.
16 . The method of claim 15 , wherein the second stream further comprises diethylene glycol and/or triethylene glycol.
17 . The method of claim 13 , further comprising recovering at least a portion of alkylene oxide from the first stream for pure alkylene oxide production.
18 . The method of claim 13 , further comprising:
recycling at least a portion of the first stream to the first reactor for producing additional alkylene glycol.
19 . The method of claim 13 , wherein the separating of first effluent stream to produce first stream and second stream is performed at an overhead boiling temperature range of 150 to 180° C. and a pressure range of 6 to 20 bar.
20 . A method of producing alkylene glycol, the method comprising:
flowing a feed stream comprising alkylene oxide and water into a first reactor unit;
subjecting the alkylene oxide and water, in the first reactor unit, to first reaction conditions such that an effluent of the first reactor unit comprises an alkylene glycol, unreacted alkylene oxide, and unreacted water;
flowing at least a portion of the unreacted alkylene oxide and unreacted water to a second reactor unit; and
subjecting the unreacted alkylene oxide and unreacted water in the second reactor unit to second reaction conditions sufficient to produce additional alkylene glycol;
wherein the second reactor unit is a reactive distillation column and higher mono alkylene to di alkylene glycol ratio is produced even at lower water to alkylene oxide ratio,
wherein the alkylene glycol is ethylene glycol and the alkylene oxide is ethylene oxide, and
wherein the reaction conditions in the first reactor unit comprise: a reactor inlet temperature in a range of 120 to 160° C., a reaction pressure of 18 to 25 bar, and a residence time of 0.5 to 8.0 minutes.