US5151190A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for separating a liquid mixture
Assignee: Mitsubishi Chemical Corp
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Filing: 1991-12-27
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Granted: 1992-09-29
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Expires: 2011-12-27
Abstract
Abstract A method for separating water by pervaporation from a liquid mixture comprising isopropanol and water, which comprises (a) heating the liquid mixture, then supplying the heated mixture to a pervaporation membrane module unit using a polyimide-type separating membrane to conduct separation of the liquid mixture, recycling a part or whole of the liquid not permeated through the membrane to a feed liquid mixture, supplying a fresh feed liquid mixture to an optional place in the circulation route, and withdrawing the liquid mixture from an optional place in the circulation route, (b) controlling the amount of the liquid to be recycled among the liquid not permeated through the membrane to a level of at least 10 times by volume the amount of the fresh feed liquid mixture, and (c) controlling the difference between the liquid temperature at the inlet of the membrane module unit and the liquid temperature at the outlet of the membrane module unit to a level of at most 20 DEG C.
Inventors
- 👤 Furuto Seiryo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 12:53
CPC Classifications
B; B01; B01D; B01D61/00; B01D61/36; B01D61/364; B01D61/362; B01D61/3621; B01D63/00; B01D63/02; B01D63/021; B01D67/00; B01D67/0081; B01D67/0093; B01D67/00931; B01D69/00; B01D69/08; B01D69/10; B01D69/107; B01D69/12; B01D69/1213; B01D71/00; B01D71/06; B01D71/58; B01D71/62; B01D71/64; B01D71/641; C; C07; C07C; C07C29/00; C07C29/74; C07C29/76; C07C29/80; B01D2257/00; B01D2257/80; B01D2311/00; B01D2311/10; B01D2311/16; B01D2311/25; B01D2311/252; B01D2311/2523; B01D2325/00; B01D2325/36
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
163 words
A method for separating water by pervaporation from a liquid mixture comprising isopropanol and water, which comprises (a) heating the liquid mixture, then supplying the heated mixture to a pervaporation membrane module unit using a polyimide-type separating membrane to conduct separation of the liquid mixture, recycling a part or whole of the liquid not permeated through the membrane to a feed liquid mixture, supplying a fresh feed liquid mixture to an optional place in the circulation route, and withdrawing the liquid mixture from an optional place in the circulation route, (b) controlling the amount of the liquid to be recycled among the liquid not permeated through the membrane to a level of at least 10 times by volume the amount of the fresh feed liquid mixture, and (c) controlling the difference between the liquid temperature at the inlet of the membrane module unit and the liquid temperature at the outlet of the membrane module unit to a level of at most 20° C.
Claim 2
Independent Claim
163 words
A method for separating water by pervaporation from a liquid mixture comprising isopropanol and water, which comprises (a) heating the liquid mixture, then supplying the heated mixture to a pervaporation membrane module unit using a polyimide-type separating membrane to conduct separation of the liquid mixture, recycling a part or whole of the liquid not permeated through the membrane to a feed liquid mixture, supplying a fresh feed liquid mixture to an optional place in the circulation route, and withdrawing the liquid mixture from an optional place in the circulation route, (b) controlling the amount of the liquid to be recycled among the liquid not permeated through the membrane to a level of at least 10 times by volume the amount of the fresh feed liquid mixture, and (c) controlling the difference between the liquid temperature at the inlet of the membrane module unit and the liquid temperature at the outlet of the membrane module unit to a level of at most 20° C.
Claim 3
Dependent Claim
41 words
The method according to claim 1, wherein the amount of the liquid to be recycled among the liquid not permeated through the membrane is adjusted to a level of 15 times by volume the amount of the fresh feed liquid mixture.
Claim 4
Dependent Claim
43 words
The method according to claim 1, wherein the difference between the liquid temperature at the inlet of the membrane module unit and the liquid temperature at the outlet of the membrane module unit, is adjusted to a level of at most 15° C.
Claim 5
Dependent Claim
16 words
The method according to claim 1, wherein the polyimide-type separating membrane is a hollow fiber membrane.
Claim 6
Dependent Claim
31 words
The method according to claim 1, wherein the polyimide-type membrane is a composite separating membrane comprising a thin layer of an aromatic polyimide, an aromatic polyamide imide or a mixture thereof.
Claim 7
Dependent Claim
37 words
The method according to claim 5, wherein the composite separating membrane has a thin layer of a hydrophilic polymer formed on a finely porous film of an aromatic polyimide, an aromatic polyamide imide or a mixture thereof.
Claim 8
Dependent Claim
77 words
The method according to claim 6, wherein the hydrophilic polymer is selected so that the separation factor of a homogeneous film made solely of the aromatic polyimide or the aromatic polyamide imide is higher by at least 10% than the separation factor of a homogeneous film made solely of the hydrophilic polymer, as measured by a pervaporation method at a weight ratio of water/isopropanol=13/87 at a temperature of 80° C. at a vacuum degree of 5 Torr.
Claim 9
Dependent Claim
32 words
The method according to claim 6, wherein the hydrophilic polymer is selected from the group consisting of a polyvinyl alcohol, an ethylene-vinyl acetate copolymer saponification product, a polyamide and a mixture thereof.
Claim 10
Dependent Claim
21 words
The method according to claim 6, wherein the surface of the finely porous film is treated with a silane coupling agent.
Claim 11
Independent Claim
174 words
A method for recovering isopropanol of high purity by removing water by pervaporation from a liquid mixture comprising water and isopropanol used for cleaning precision parts, which comprises (a) heating the liquid mixture, then supplying the heated mixture to a pervaporation membrane module unit using a polyimide-type separating membrane to conduct separation of the liquid mixture, recycling a part or whole of the liquid not permeated through the membrane to a feed liquid mixture, supplying a fresh feed liquid mixture to an optional place in the circulation route, and withdrawing the liquid mixture from an optional place in the circulation route, (b) controlling the amount of the liquid to be recycled among the liquid not permeated through the membrane to a level of at least 10 times by volume the amount of the fresh feed liquid mixture, and (c) controlling the difference between the liquid temperature at the inlet of the membrane module unit and the liquid temperature at the outlet of the membrane module unit to a level of at most 20° C.
Claim 12
Independent Claim
174 words
A method for recovering isopropanol of high purity by removing water by pervaporation from a liquid mixture comprising water and isopropanol used for cleaning precision parts, which comprises (a) heating the liquid mixture, then supplying the heated mixture to a pervaporation membrane module unit using a polyimide-type separating membrane to conduct separation of the liquid mixture, recycling a part or whole of the liquid not permeated through the membrane to a feed liquid mixture, supplying a fresh feed liquid mixture to an optional place in the circulation route, and withdrawing the liquid mixture from an optional place in the circulation route, (b) controlling the amount of the liquid to be recycled among the liquid not permeated through the membrane to a level of at least 10 times by volume the amount of the fresh feed liquid mixture, and (c) controlling the difference between the liquid temperature at the inlet of the membrane module unit and the liquid temperature at the outlet of the membrane module unit to a level of at most 20° C.
Claim 13
Dependent Claim
22 words
The method according to claim 10, wherein isopropanol of high purity is isopropanol having a water content of not more than 10%.
References Cited (Backward Citations)
US4774365A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-09-29 | 1996-03-30 | 1996-09-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-29 | 2000-03-30 | 2000-09-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-29 | 2004-03-30 | 2004-09-29 | $7700.00 | Window Closed / Lapsed |