US4605427A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cryogenic triple-pressure air separation with LP-to-MP latent-heat-exchange
Assignee: Individual
•
Filing: 1983-06-06
•
Granted: 1986-08-12
•
Expires: 2003-06-06
Abstract
Abstract This invention makes possible a substantial improvement in the distillation column efficiencies of a cryogenic air separation process while still retaining high reboil rates through the argon stripping section of the low pressure column. Those advantages result in a lower energy requirement for separating air while still yielding medium to high oxygen purity. In a triple pressure column arrangement, the medium pressure column efficiency is increased by reboiling it at two or more locations by latent heat exchange with both the high pressure and low pressure columns. The LP column vapor which reboils the MP column is taken from above at least part of the argon stripper, to maintain a high reboil rate through the stripper.
Inventors
- 👤 Donald C. Erickson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:35
CPC Classifications
F; F25; F25J; F25J3/00; F25J3/02; F25J3/04; F25J3/04151; F25J3/04187; F25J3/04193; F25J3/04206; F25J3/04212; F25J3/04006; F25J3/04078; F25J3/0409; F25J3/04248; F25J3/04284; F25J3/04309; F25J3/04333; F25J3/04369; F25J3/04436; F25J3/04448; F25J3/04642; F25J3/04648; F25J3/04654; F25J3/04709; F25J3/04715; F25J3/04763; F25J3/04769; F25J3/04854; F25J3/0486; F25J2200/00; F25J2200/08; F25J2200/50; F25J2200/52; F25J2200/54; F25J2200/90; F25J2205/00; F25J2205/02; F25J2205/60; F25J2235/00; F25J2235/02; F25J2240/00; F25J2240/40; F25J2240/60; F25J2250/00; F25J2250/30; F25J2250/50; Y; Y10; Y10S; Y10S62/00; Y10S62/923; Y10S62/924
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
166 words
A process for producing oxygen of at least about 96% purity comprising (a) feeding at least part of a supply of moisture and CO 2 free air to a high pressure (HP) rectification column; (b) feeding at least part of the oxygen enriched liquid bottom product from the HP column to a medium pressure (MP) column; (c) feeding substantially all of the further oxygen enriched liquid bottom product from the MP column to a low pressure (LP) column comprised of an argon stripping section and at least one rectification section; (d) reboiling both the MP and LP columns by latent heat exchange with HP column vapor; (e) exchanging latent heat between vapor from an intermediate height of the LP column and liquid from an intermediate height of the MP column, and returning reflux to the LP column and reboil to the MP column; (f) withdrawing gaseous N 2 from the MP column overhead (g) withdrawing oxygen of said purity from the bottom of said LP column.
Claim 2
Dependent Claim
166 words
A process for producing oxygen of at least about 96% purity comprising (a) feeding at least part of a supply of moisture and CO 2 free air to a high pressure (HP) rectification column; (b) feeding at least part of the oxygen enriched liquid bottom product from the HP column to a medium pressure (MP) column; (c) feeding substantially all of the further oxygen enriched liquid bottom product from the MP column to a low pressure (LP) column comprised of an argon stripping section and at least one rectification section; (d) reboiling both the MP and LP columns by latent heat exchange with HP column vapor; (e) exchanging latent heat between vapor from an intermediate height of the LP column and liquid from an intermediate height of the MP column, and returning reflux to the LP column and reboil to the MP column; (f) withdrawing gaseous N 2 from the MP column overhead (g) withdrawing oxygen of said purity from the bottom of said LP column.
Claim 3
Dependent Claim
56 words
The process according to claim 1 further comprising refluxing the rectification section of the LP column by latent heat exchange with boiling liquid nitrogen; recycling liquid overhead product from the LP column to an intermediate height of the MP column; and withdrawing substantially all of the gaseous oxygen product from the bottom of the LP column.
Claim 4
Dependent Claim
41 words
The process according to claim 1 further comprising refluxing the rectification section of the LP column at least partly by direct injection of liquid nitrogen; and recycling at least part of the nitrogen rectifier vapor to the MP column by compression.
Claim 5
Dependent Claim
55 words
The process according to claim 1 further comprising withdrawing oxygen of at least 98% purity from the LP column bottom in liquid phase; gasifying the liquid oxygen by latent heat exchange with a vapor from the LP column; and returning at least part of the condensed LP column vapor to the LP column as reflux.
Claim 6
Dependent Claim
30 words
The process according to claim 4 further comprising reducing the pressure of the liquid oxygen prior to latent heat exchange with LP column vapor, and compressing the product gaseous oxygen.
Claim 7
Dependent Claim
53 words
The process according to claim 5 further comprising removing crude argon from the top of the LP column rectification section and refluxing that section by latent heat exchange between overhead vapor and at least one of MP column liquid from an intermediate height and at least part of the said oxygen enriched liquid.
Claim 8
Dependent Claim
44 words
The process according to claim 6 further comprising providing a second rectification section for the LP column; removing a fluid containing at least nitrogen from the LP column using that rectification section; and recycling at least part of that fluid to the MP column.
Claim 9
Dependent Claim
63 words
The process according to claim 4 further comprising removing crude argon vapor of at least 70% purity from the top of the LP column rectification section; warming, compressing, and cooling it; pressurizing the liquid oxygen with a pump; exchanging latent heat between the pressurized liquid oxygen and the compressed crude argon; and returning the condensed crude argon to the rectification column as reflux.
Claim 10
Dependent Claim
26 words
The process according to claim 8 further comprising providing a second rectification section for the LP column for removal of nitrogen-containing fluid from the LP column.
Claim 11
Dependent Claim
81 words
The process according to claim 1 wherein the HP column pressure is in the range of 3 to 6 ATA, the MP column pressure is in the range of 1 to 2 ATA, the LP column pressure is in the range of 0.6 to 1.5 ATA, and at least 0.1 ATA lower than MP column pressure, and wherein the MP column intermediate height liquid supplied to exchange latent heat with LP column vapor has a composition of at least 50% oxygen.
Claim 12
Dependent Claim
33 words
The process according to claim 1 further comprising reboiling the MP column by latent heat exchange with at least one of vapor from an intermediate height of the HP column and feed air.
Claim 13
Independent Claim
103 words
An apparatus comprising: means designed for separating from air, oxygen of at least 96% purity by cryogenic distillation including a high pressure rectification column; a medium pressure distillation column which is reboiled in part by the HP column; a low pressure distillation column comprising rectifier and argon stripper which is reboiled by the HP column; a reboiler/reflux condenser which exchanges latent heat between LP column intermediate height vapor and MP column intermediate height liquid; and means for withdrawing oxygen of said purity from the bottom of said LP column And a conduit for withdrawal of gaseous N 2 from the MP column overhead.
Claim 14
Independent Claim
103 words
An apparatus comprising: means designed for separating from air, oxygen of at least 96% purity by cryogenic distillation including a high pressure rectification column; a medium pressure distillation column which is reboiled in part by the HP column; a low pressure distillation column comprising rectifier and argon stripper which is reboiled by the HP column; a reboiler/reflux condenser which exchanges latent heat between LP column intermediate height vapor and MP column intermediate height liquid; and means for withdrawing oxygen of said purity from the bottom of said LP column And a conduit for withdrawal of gaseous N 2 from the MP column overhead.
Claim 15
Dependent Claim
38 words
Apparatus according to claim 12 further comprising means for refluxing an intermediate height of the LP column by exchanging latent heat between liquid oxygen withdrawn from the LP column bottom and vapor from the LP column intermediate height.
Claim 16
Dependent Claim
59 words
Apparatus according to claim 12 in which the LP column overhead fluid is predominantly N 2 and further comprising: a conduit for directly injecting liquid N 1 into the LP column overhead; and at least one conduit and compressor for withdrawing LP column overhead gas for delivery to at least one of the MP column and the ambient exhaust.
Claim 17
Dependent Claim
51 words
Apparatus according to claim 12 in which the LP column overhead fluid is predominantly N 2 and further comprising: a reflux condenser for the LP column which exchanges latent heat with liquid N 2 from the HP column and a means for transporting LP column overhead liquid to the MP column.
Claim 18
Dependent Claim
55 words
Apparatus according to claim 12 wherein the LP column overhead fluid is predominantly argon and further comprising: means for refluxing an intermediate height of the LP column by exchanging latent heat between liquid oxygen withdrawn from the LP column bottom and vapor from the LP column intermediate height; and a compressor for the gasified oxygen.
Claim 19
Dependent Claim
78 words
Apparatus according to claim 12 wherein the LP column overhead fluid is predominantly argon and comprises no more than 30% oxygen and further comprising: a means for increasing the pressure of the LP column overhead vapor; a means for increasing the pressure of the LP column bottom liquid oxygen; a means for exchanging latent heat between pressurized overhead vapor and pressurized liquid oxygen; and a means for transporting condensed overhead vapor back to the LP column as reflux.
Claim 20
Dependent Claim
36 words
Apparatus according to claim 12 further comprising a second rectification section of the LP column wherein the overhead fluid of the first rectification section is predominantly nitrogen and that of the second section is predominantly argon.
Claim 21
Dependent Claim
128 words
In a process for producing oxygen of at least 96% purity in a triple pressure distillation apparatus comprised of a high pressure column, medium pressure column, and low pressure column comprised of an argon stripping section and at least one rectification section, the improvement comprising: providing intermediate reflux to the LP column and intermediate reboil to the MP column by indirect exchange of latent heat from LP column intermediate height vapor to MP column intermediate height liquid; reboiling both the MP and LP columns by latent heat exchange with HP column vapor; transporting substantially all the MP column bottom liquid to the LP column for further purification; withdrawing gaseous overhead nitrogen from the MP column; and withdrawing oxygen of said purity from the bottom of said LP column.
Claim 22
Dependent Claim
128 words
In a process for producing oxygen of at least 96% purity in a triple pressure distillation apparatus comprised of a high pressure column, medium pressure column, and low pressure column comprised of an argon stripping section and at least one rectification section, the improvement comprising: providing intermediate reflux to the LP column and intermediate reboil to the MP column by indirect exchange of latent heat from LP column intermediate height vapor to MP column intermediate height liquid; reboiling both the MP and LP columns by latent heat exchange with HP column vapor; transporting substantially all the MP column bottom liquid to the LP column for further purification; withdrawing gaseous overhead nitrogen from the MP column; and withdrawing oxygen of said purity from the bottom of said LP column.
Claim 23
Dependent Claim
49 words
The process according to claim 19 further comprising withdrawing liquid oxygen bottom product of at least 98% purity from the LP column; exchanging latent heat between the liquid oxygen and a vapor from the LP column; and refluxing the LP column with at least part of the condensed vapor.
Claim 24
Dependent Claim
68 words
The process according to claim 20 wherein the LP column rectification section overhead fluid is predominantly nitrogen and further comprising: directly injecting liquid nitrogen into the LP column overhead; directly injecting part of the oxygen enriched liquid from the HP column bottom into an LP column intermediate height; thermocompressing LP column overhead vapor to the MP column; and thermocompressing LP column intermediate height vapor to the MP column.
References Cited (Backward Citations)
US2699046A
Cited
US3688513A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-08-11 | 1990-02-10 | 1990-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-08-11 | 1994-02-10 | 1994-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-08-11 | 1998-02-10 | 1998-08-12 | $7700.00 | Window Closed / Lapsed |