US4233120A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Distillation method for solvent recovery
Assignee: John Gladstone and Co Engineering Ltd
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Filing: 1978-04-14
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Granted: 1980-11-11
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Expires: 1998-04-14
Abstract
Abstract An improved solvent recovery process comprising distilling soiled solvent in a main still and conducting hot solvent vapor through a heat exchanger associated with a tank in which an azeotropic mixture of water and soiled solvent is maintained, which mixture boils at a temperature lower than the boiling point of the solvent alone. A series of tanks feed soiled solvent to the azeotropic mixture tank and then to the main still, and heat exchangers fed by the vapor from the main still and the vapor from the azeotropic mixture tank pre-heat the soiled solvent. Automatic control of water injection into the azeotropic mixture tank in dependence upon the temperature of conductivity of the tank contents maintains the composition of the azeotropic mixture, the injected water being taken from separators which separate water from condensate of the main still and azeotropic mixture tank vapors.
Inventors
- 👤 David Finlay-Maxwell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:19
CPC Classifications
B; B01; B01D; B01D1/00; B01D1/26; B01D3/00; B01D3/34; B01D3/36
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
185 words
A solvent recovery process comprising (a) distilling a first volume of a soiled solvent of a type herein described in order to separate solvent vapor from the soiling contaminants; (b) passing the solvent vapor in indirect heat transfer relationship with a second volume of soiled solvent so as to effect heating of said second volume; (c) introducing controlled amounts of water into said second volume such that said second volume comprises an azeotropic mixture of water and solvent having a boiling point lower than that of the solvent, whereby said azeotropic mixture can be heated to boiling by heat transfer from said solvent vapor; (d) condensing the solvent vapor and the vapor arising from boiling of the said azeotropic mixture of water and solvent; (e) separating water from such condensate as is thereby obtained so as to recover the solvent therefrom; (f) transferring and distilling contaminant sludge from the distillation of said first volume out of said first volume; and (g) passing solvent vapor arising from such distillation of said contaminant sludge in indirect heat exchange relationship with said second volume for heating the same.
Claim 2
Dependent Claim
185 words
A solvent recovery process comprising (a) distilling a first volume of a soiled solvent of a type herein described in order to separate solvent vapor from the soiling contaminants; (b) passing the solvent vapor in indirect heat transfer relationship with a second volume of soiled solvent so as to effect heating of said second volume; (c) introducing controlled amounts of water into said second volume such that said second volume comprises an azeotropic mixture of water and solvent having a boiling point lower than that of the solvent, whereby said azeotropic mixture can be heated to boiling by heat transfer from said solvent vapor; (d) condensing the solvent vapor and the vapor arising from boiling of the said azeotropic mixture of water and solvent; (e) separating water from such condensate as is thereby obtained so as to recover the solvent therefrom; (f) transferring and distilling contaminant sludge from the distillation of said first volume out of said first volume; and (g) passing solvent vapor arising from such distillation of said contaminant sludge in indirect heat exchange relationship with said second volume for heating the same.
Claim 3
Dependent Claim
76 words
A solvent recovery process according to claim 1 wherein as the said second volume is boiled off it is replenished by the addition of further soiled solvent and water, the temperature of said second volume being monitored and said water being introduced whenever the temperature of said second volume rises above a predetermined threshold level substantially corresponding to the boiling point of said azeotropic mixture, so as to maintain the azeotropic composition of said second volume.
Claim 4
Dependent Claim
43 words
A solvent recovery process according to claim 1 or 2, wherein said second volume is replenished from a third volume of soiled solvent, and vapor arising from boiling of said second volume is passed in indirect heat exchange relationship with said third volume.
Claim 5
Dependent Claim
43 words
A solvent recovery process according to claim 3 wherein vapor arising from distillation of said first volume is passed in indirect heat transfer relationship with said third volume of soiled solvent after passage thereof in indirect heat transfer relationship with said second volume.
Claim 6
Dependent Claim
156 words
A solvent recovery process which comprises (a) passing a soiled organic solvent of a type herein described through a plurality of tanks in series; (b) adding controlled amounts of water to the soiled solvent in the last of said tanks such that said tank contains an azeotropic mixture of water and solvent which boils at a lower temperature than does the solvent alone; (c) passing soiled solvent to a still in which it is distilled such that the solvent is evaporated to form a vapor at a temperature which is higher than the boiling point of said azeotropic mixture; (d) passing a countercurrent flow of said vapor through said tanks in series in indirect heat transfer relationship in each case with the contents of said tanks whereby said azeotropic mixture boils; and (e) condensing the vapor produced in said still and the vapor produced in said last tank; and (f) recovering condensate formed by such condensation.
Claim 7
Dependent Claim
156 words
A solvent recovery process which comprises (a) passing a soiled organic solvent of a type herein described through a plurality of tanks in series; (b) adding controlled amounts of water to the soiled solvent in the last of said tanks such that said tank contains an azeotropic mixture of water and solvent which boils at a lower temperature than does the solvent alone; (c) passing soiled solvent to a still in which it is distilled such that the solvent is evaporated to form a vapor at a temperature which is higher than the boiling point of said azeotropic mixture; (d) passing a countercurrent flow of said vapor through said tanks in series in indirect heat transfer relationship in each case with the contents of said tanks whereby said azeotropic mixture boils; and (e) condensing the vapor produced in said still and the vapor produced in said last tank; and (f) recovering condensate formed by such condensation.
Claim 8
Dependent Claim
27 words
A solvent recovery process according to claim 5, including the separation of water from the condensate formed by condensation of the vapor produced in said last tank.
Claim 9
Dependent Claim
42 words
A solvent recovery process according to claim 6, wherein said separated water is fed back into said last tank so as to maintain the azeotropic composition of the contents thereof during vaporization thereof and replenishment from the preceding tank in the series.
Claim 10
Dependent Claim
42 words
A solvent recovery process according to claim 7, including monitoring the temperature of the contents of said last tank, and introducing said water when the temperature rises above a predetermined threshold level substantially corresponding to the boiling point of said azeotropic mixture.
Claim 11
Dependent Claim
23 words
A solvent recovery process according to claim 5, wherein said soiled solvent is passed to said still from the last of said tanks.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-11-11 | 1984-05-12 | 1984-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-11 | 1988-05-12 | 1988-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-11 | 1992-05-12 | 1992-11-11 | $7700.00 | Window Closed / Lapsed |