US4466202A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Energy-efficient evaporation process with means for vapor recovery
Assignee: Bend Research Inc
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Filing: 1983-03-07
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Granted: 1984-08-21
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Expires: 2003-03-07
Abstract
Abstract A process is disclosed for the recovery and reuse of heat contained in the wet exhaust gases emanating from a solids dryer or liquor concentrator, particularly one in which drying or concentration is facilitated by purging the vapor with some noncondensable gas such as air or nitrogen. Water or solvent vapor in the moist exhaust mixture is separated from the noncondensable gas or gases by preferentially passing the vapor through a semipermeable membrane. The water or solvent vapor is then compressed and subsequently condensed in a heat exchanger, permitting recovery of its latent heat of vaporization for reuse in the evaporation process. In a drying process, this recovered energy is conveniently used to reheat the dry gases that exit from the membrane separator, permitting the hot, dry gases to be recirculated through the dryer. Alternatively, an indirect heat exchanger may be used to transfer this heat to the material being dried. In an evaporative process for the concentration of a liquor, the recovered energy may be used either to preheat the dry purge gases or to heat the dilute liquor being concentrated.
Inventors
- 👤 Ulrich Merten
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 19:00
CPC Classifications
F; F28; F28D; F28D21/00; F28D21/0001; F28D21/0014; F26; F26B; F26B21/00; F26B21/20; F26B21/25; F26B21/30; F26B21/33; F26B23/00; F26B23/001; F26B23/002; F26B23/004; F26B25/00; F26B25/005; F26B25/006; Y; Y02; Y02B; Y02B30/00; Y02B30/52; Y02P; Y02P70/00; Y02P70/10
Claims Analysis
Total Claims: 40
Claim 1
Independent Claim
132 words
An energy-efficient process for the recovery of latent heat from a drying process comprising (1) contacting a material containing a volatile liquid with a gaseous drying medium and supplying heat to said drying medium or to said material and thereby producing an exhaust mixture of noncondensable gas and condensable vapor, (2) separating the condensable vapor in said exhaust mixture by passing it through a nonporous nonionic polymeric membrane which is substantially permeable to said condensable vapor and substantially impermeable to said noncondensable gas, (3) transferring said separated condensable vapor, together with the latent heat of condensation contained therein, to a compressor, (4) compressing in said compressor said separated condensable vapor, and (5) condensing said separated condensable vapor by heat exchange, thereby recovering the latent heat of condensation of said separated condensable vapor.
Claim 2
Dependent Claim
132 words
An energy-efficient process for the recovery of latent heat from a drying process comprising (1) contacting a material containing a volatile liquid with a gaseous drying medium and supplying heat to said drying medium or to said material and thereby producing an exhaust mixture of noncondensable gas and condensable vapor, (2) separating the condensable vapor in said exhaust mixture by passing it through a nonporous nonionic polymeric membrane which is substantially permeable to said condensable vapor and substantially impermeable to said noncondensable gas, (3) transferring said separated condensable vapor, together with the latent heat of condensation contained therein, to a compressor, (4) compressing in said compressor said separated condensable vapor, and (5) condensing said separated condensable vapor by heat exchange, thereby recovering the latent heat of condensation of said separated condensable vapor.
Claim 3
Dependent Claim
30 words
The process of claim 1 wherein the noncondensable gas from which said vapor has been separated, together with the sensible heat contained in said noncondensable gas, is recovered and reused.
Claim 4
Dependent Claim
19 words
The process of claim 1 wherein said condensable vapor is water vapor and its heat of condensation is reused.
Claim 5
Dependent Claim
17 words
The process of claim 3 wherein said nonporous nonionic polymeric membrane is prepared from a hydrophilic polymer.
Claim 6
Dependent Claim
47 words
The process of claim 3 wherein said nonporous nonionic polymeric membrane is selected from silicone rubbers, natural rubber, synthetic rubbers, cellulose, cellulose esters, polyvinyl alcohol, polyethyleneimine, arylene oxide polymers, arylene oxide ion-exchange polymers, polystyrene sulfonates, polyvinyl butyral, polyvinylacetate, polyethylmethacrylate, polybutadiene, aliphatic polyamides, aromatic polyamides, polyimides, and polybenzimidazoles.
Claim 7
Dependent Claim
28 words
The process of claim 1 wherein said condensable vapor is an organic solvent vapor selected from chlorinated hydrocarbons, aliphatic hydrocarbons, aromatic hydrocarbons, ketones, ethers, alcohols, and carbon disulfide.
Claim 8
Dependent Claim
37 words
The process of claim 6 wherein said nonporous nonionic polymeric membrane is selected from polyamides, polyethylene, polypropylene, cellulose acetate, silicone rubber, poly(butadiene-acrylonitrile) rubber, polyethylene-styrene copolymers, polyvinylacetate, poly(ethyleneterephthalate), poly(tetrafluoroethylene)-poly(4-vinyl pyridine or N-vinyl pyrrolidone) graft copolymers, and acrylonitrilevinylacetate copolymers.
Claim 9
Dependent Claim
151 words
In an industrial drying process for drying material, said process utilizing hot, dry gas as the drying medium and producing moist or solvent-containing exhaust gas, the improvement comprising: (a) separating the exhaust gas into a warm, dry noncondensable gas component and a condensable vapor component by passing the condensable vapor in said exhaust mixture through a nonporous nonionic polymeric membrane that is substantially permeable to said condensable vapor and substantially impermeable to said noncondensable gas; (b) transferring said separated condensable vapor, together with the heat of condensation contained therein, to a compressor; (c) compressing in said compressor the condensable vapor in said condensable vapor component; (d) condensing the condensable vapor in said condensable vapor component by heat exchange, thereby recovering the heat of condensation of said condensable vapor; and (e) transferring by heat transfer means said heat of condensation to said hot, dry gas-drying medium or to the material being dried.
Claim 10
Dependent Claim
151 words
In an industrial drying process for drying material, said process utilizing hot, dry gas as the drying medium and producing moist or solvent-containing exhaust gas, the improvement comprising: (a) separating the exhaust gas into a warm, dry noncondensable gas component and a condensable vapor component by passing the condensable vapor in said exhaust mixture through a nonporous nonionic polymeric membrane that is substantially permeable to said condensable vapor and substantially impermeable to said noncondensable gas; (b) transferring said separated condensable vapor, together with the heat of condensation contained therein, to a compressor; (c) compressing in said compressor the condensable vapor in said condensable vapor component; (d) condensing the condensable vapor in said condensable vapor component by heat exchange, thereby recovering the heat of condensation of said condensable vapor; and (e) transferring by heat transfer means said heat of condensation to said hot, dry gas-drying medium or to the material being dried.
Claim 11
Dependent Claim
19 words
The process of claim 8 wherein said condensable vapor component is compressed with a mechanical compressor or vacuum pump.
Claim 12
Dependent Claim
20 words
The process of claim 8 wherein said warm, dry noncondensable gas component is recirculated for reuse as the drying medium.
Claim 13
Dependent Claim
34 words
The process of claim 10 wherein said heat transfer means is a vapor-to-gas heat exchanger which effects a transfer of the heat of condensation of said vapor to said hot, dry gas drying medium.
Claim 14
Dependent Claim
17 words
The process of claim 8 wherein said condensable vapor component of said exhaust gas is water vapor.
Claim 15
Dependent Claim
17 words
The process of claim 12 wherein said nonporous nonionic polymeric membrane is prepared from a hydrophilic polymer.
Claim 16
Dependent Claim
47 words
The process of claim 13 wherein said nonporous nonionic polymeric membrane is selected from silicone rubbers, natural rubber, synthetic rubbers, cellulose, cellulose esters, polyvinyl alcohol, polyethyleneimine, arylene oxide polymers, arylene oxide ion-exchange polymers, polystyrene sulfonates, polyvinyl butyral, polyvinylacetate, polyethylmethacrylate, polybutadiene, aliphatic polyamides, aromatic polyamides, polyimides, and polybenzimidazoles.
Claim 17
Dependent Claim
14 words
The process of claim 8 wherein the hot, dry gas is air or nitrogen.
Claim 18
Dependent Claim
33 words
The process of claim 8 wherein said condensable vapor component of said exhaust gas is an organic solvent vapor selected from chlorinated hydrocarbons, aliphatic hydrocarbons, aromatic hydrocarbons, ketones, ethers, alcohols, and carbon disulfide.
Claim 19
Dependent Claim
38 words
The process of claim 16 wherein said nonporous nonionic polymeric membrane is selected from polyamides, polyethylene, polypropylene, cellulose acetate, silicone rubber, poly(butadiene-acrylonitrile) rubber, polyethylene-styrene copolymers, polyvinylacetate, poly(ethylene terephthalate), poly(tetrafluoroethylene)-poly(4-vinyl pyridine or N-vinyl pyrrolidone) graft copolymers, and acrylonitrilevinylacetate copolymers.
Claim 20
Dependent Claim
23 words
The process of claim 8 wherein the relative humidity of the moist or solvent-containing exhaust gas is from about 30% to about 100%.
Claim 21
Dependent Claim
24 words
The process of claim 8 wherein the temperature of the moist or solvent-containing exhaust gas is from about 40° C. to about 125° C.
Claim 22
Dependent Claim
26 words
The process of claim 8 wherein the partial pressure of water or solvent vapor in the moist or solvent-containing exhaust gas is at least 0.1 atm.
Claim 23
Dependent Claim
27 words
The process of claim 8 wherein the heat transfer means is an indirect heat exchanger and the heat of condensation is transferred to the material being dried.
Claim 24
Dependent Claim
167 words
In a process for the concentration of a liquid mixture or solution by evaporation, said process comprising heating the liquid mixture or solution, contacting the liquid mixture or solution with a substantially dry, gaseous stream, and thereby producing a moist, gaseous exhaust mixture, the improvement comprising: (a) separating the moist, gaseous exhaust mixture into a warm, dry noncondensable gas component and a condensable vapor component by passing said exhaust mixture through a nonporous nonionic polymeric membrane that is substantially permeable to said condensable vapor component and substantially impermeable to said noncondensable gas component; (b) transferring said separated condensable vapor, together with the heat of condensation contained herein, to a compressor; (c) compressing in said compressor the condensable vapor in said condensable vapor component; (d) condensing the condensable vapor in said vapor component by heat exchange, thereby recovering the heat of condensation of said condensable vapor; and (e) transferring by heat transfer means said heat of condensation to the gaseous drying medium or to the material being concentrated.
Claim 25
Dependent Claim
167 words
In a process for the concentration of a liquid mixture or solution by evaporation, said process comprising heating the liquid mixture or solution, contacting the liquid mixture or solution with a substantially dry, gaseous stream, and thereby producing a moist, gaseous exhaust mixture, the improvement comprising: (a) separating the moist, gaseous exhaust mixture into a warm, dry noncondensable gas component and a condensable vapor component by passing said exhaust mixture through a nonporous nonionic polymeric membrane that is substantially permeable to said condensable vapor component and substantially impermeable to said noncondensable gas component; (b) transferring said separated condensable vapor, together with the heat of condensation contained herein, to a compressor; (c) compressing in said compressor the condensable vapor in said condensable vapor component; (d) condensing the condensable vapor in said vapor component by heat exchange, thereby recovering the heat of condensation of said condensable vapor; and (e) transferring by heat transfer means said heat of condensation to the gaseous drying medium or to the material being concentrated.
Claim 26
Dependent Claim
32 words
The process of claim 22 wherein said condensable vapor component is compressed with a mechanical compressor or vacuum pump, said compressor or pump being driven by a motor or a steam-driven turbine.
Claim 27
Dependent Claim
21 words
The process of claim 22 said warm, dry noncondensable gas component is recirculated for reuse as the substantially dry gaseous stream.
Claim 28
Dependent Claim
26 words
The process of claim 24 wherein said heat transfer means is a vapor-to-gas heat exchanger which transfers said heat of condensation to said gaseous drying medium.
Claim 29
Dependent Claim
12 words
The process of claim 22 wherein said condensable vapor is water vapor.
Claim 30
Dependent Claim
17 words
The process of claim 26 wherein said nonporous nonionic polymeric membrane is prepared from a hydrophilic polymer.
Claim 31
Dependent Claim
46 words
The process of claim 27 wherein said nonporous polymeric membrane is selected from silicone rubbers, natural rubber, synthetic rubbers, cellulose, cellulose esters, polyvinyl alcohol, polyethyleneimine, arylene oxide polymers, arlene oxide ion-exchange polymers, polystyrene sulfonates, polyvinyl butyral, polyvinylacetate, polyethylmethacrylate, polybutadiene, aliphatic polyamides, aromatic polyamides, polyimides, and polybenzimidazoles.
Claim 32
Dependent Claim
15 words
The process of claim 22 wherein the substantially dry gaseous stream is air or nitrogen.
Claim 33
Dependent Claim
29 words
The process of claim 22 wherein said condensable vapor component is an organic solvent vapor selected from chlorinated hydrocarbons, aliphatic hydrocarbons, aromatic hydrocarbons, ketones, ethers, alcohols, and carbon disulfide.
Claim 34
Dependent Claim
38 words
The process of claim 30 wherein said nonporous nonionic polymeric membrane is selected from polyamides, polyethylene, polypropylene, cellulose acetate, silicone rubber, poly(butadiene-acrylonitrile) rubber, polyethylene-styrene copolymers, polyvinylacetate, poly(ethylene terephthalate), poly(tetrafluoroethylene-poly(4-vinyl pyridine or N-vinyl pyrrolidone) graft copolymers, and acrylonitrilevinylacetate copolymers.
Claim 35
Dependent Claim
16 words
The process of claims 6, 16 or 30 wherein said condensable vapor is recovered after condensation.
Claim 36
Dependent Claim
22 words
The process of claim 22 wherein the relative humidity of the moist, gaseous exhaust mixture is from about 30% to about 100%.
Claim 37
Dependent Claim
23 words
The process of claim 22 wherein the temperature of the moist, gaseous exhaust mixture is from about 40° C. to about 125° C.
Claim 38
Dependent Claim
25 words
The process of claim 22 wherein the partial pressure of water or solvent vapor in the moist, gaseous exhaust mixture is at least 0.1 atm.
Claim 39
Dependent Claim
56 words
The process of claim 22 wherein said condensable vapor component is compressed and condensed on one surface of an indirect heat exchanger, another surface of said indirect heat exchanger being in contact with said liquid mixture or solution whereby the heat of condensation of said condensable vapor component is transferred to said liquid mixture or solution.
Claim 40
Dependent Claim
60 words
The process of claim 22 wherein said heat transfer means is an indirect heat exchanger and said noncondensable vapor component is compressed and used to preheat said liquid mixture or solution by passing said compressed vapor to and condensing said compressed vapor in said indirect heat exchanger, one surface of which is in contact with said liquid mixture or solution.
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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) | 1987-08-21 | 1988-02-20 | 1988-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-21 | 1992-02-20 | 1992-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-21 | 1996-02-20 | 1996-08-21 | $7700.00 | Window Closed / Lapsed |