US3928192A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Buffered, weak ion-exchange water demineralization process
Assignee: Aerojet Rocketdyne Inc
•
Filing: 1974-06-06
•
Granted: 1975-12-23
•
Expires: 1994-06-06
Abstract
Abstract A novel process for water demineralization involving the use of separate beds of weakly acidic cation exchange resin, weakly basic anionic exchange resin and a third column of weakly acidic cationic exchange resin. The first column of cation resin is buffered with a suitable base such as ammonia or an amine. When the saline feed is passed through the system, the cations of the feed are exchanged for the buffer, releasing buffered salts. The buffered salts when passed through the anion exchange column are split, releasing the buffer that is then deposited on the third cation resin column. The latter column is then used as the first separate bed during the next demineralization cycle. Thus, the buffer is internally looped, preventing contamination and also resulting in a saving of feed chemical. This process allows the efficient use of weak cation and anion exchange resins in a separate fixed-bed configuration. The process is adaptable to deionizing brackish water and tertiary waste water from sewage plants, to remove water soluble ions.
Inventors
- 👤 Jr Arthur Katzakian
- 👤 David O Depree
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:16
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/42; B; B01; B01J; B01J39/00; B01J39/04; B01J39/07; B01J47/00; B01J47/10; B01J47/11; C02F1/66; C02F2001/422; C02F2001/425; C02F2103/00; C02F2103/08
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
41 words
A PROCESS FOR DEMINERALIZING WATER COMPRISING THE STEPS OF: PASSING AN AMINE BUFFER THROUGH A BED OF WEAKLY ACIDIC CATION EXCHANGE RESIN IN HYDROGEN FORM TO FORM A FIRST BED CONTAINING AN AMINE SALT OF THE CATION RESIN OF THE FORMULA:
Claim 2
Dependent Claim
41 words
A PROCESS FOR DEMINERALIZING WATER COMPRISING THE STEPS OF: PASSING AN AMINE BUFFER THROUGH A BED OF WEAKLY ACIDIC CATION EXCHANGE RESIN IN HYDROGEN FORM TO FORM A FIRST BED CONTAINING AN AMINE SALT OF THE CATION RESIN OF THE FORMULA:
Claim 3
Dependent Claim
42 words
A process according to claim 1 in which the feedwater contains at least one soluble salt selected from the halides, sulfates, sulfites, phosphates, phosphites, carbonates, bicarbonates, nitrites and nitrates of K, Na, Ca, Br, Mg, Sn, Fe, Zn, Al, N and Cr.
Claim 4
Dependent Claim
23 words
A process according to claim 1 in which the feedwater Contains dissolved salts of Group IA and IIA alkali and alkaline earth metals.
Claim 5
Dependent Claim
16 words
A process according to claim 1 in which the pK of both resins is about 5.
Claim 6
Dependent Claim
16 words
A process according to claim 1 in which the cation exchange resin contains carboxylic acid groups.
Claim 7
Dependent Claim
17 words
A process according to claim 1 in which the anion exchange resin is a weak base polyamine.
Claim 8
Dependent Claim
36 words
A process according to claim 1 in which the amine buffer is selected from dimethylamine, trimethylamine, N,N-dimethylethanolamine, brucine, B-chlorotriethyl ammonium, 2,4-dimethylimidazol, 1-amino-isoquinoline, morpholine, N-methyl morpholine, 2,4,6-trimethylpyridine, strychnine, tyrosine amide, 2,4-lutidine, 2-pyridine methanol and N- Beta -hydroxy-ethylmorpholine.
Claim 9
Dependent Claim
16 words
A process according to claim 1 in which the cation exchange resin contains phosphonic acid groups.
Claim 10
Dependent Claim
15 words
A process according to claim 1 wherein a mixture of amines is utilized as-the buffer.
Claim 11
Dependent Claim
71 words
A process according to claim 1 in which the amine buffer is a weak base capable of being quantatively displaced by the cations of the feed, is sufficiently basic to minimize hydrolysis from the cation exchange resin salt of the buffer, is non-volatile at operating temperature of the cation exchange resin column and is a sufficiently weak base so that the salt thereof is efficiently split by the anion exchange resin.
Claim 12
Dependent Claim
18 words
A process according to claim 10 in which the pK of the buffer is from 5 to 7.
Claim 13
Dependent Claim
18 words
A process according to claim 10 in which the amine buffer has a molecular weight below about 500.
Claim 14
Dependent Claim
42 words
A process according to claim 1 further including the step of passing the second effluent through a third bed of weakly acidic cation exchange resin in hydrogen form and depositing the amine thereon to form an amine salt of the cation resin.
Claim 15
Dependent Claim
24 words
A process according to claim 13 in which the third bed when loaded with buffer is placed in the position of said first bed.
Claim 16
Dependent Claim
25 words
A process according to claim 14 further comprising the step of regenerating said first bed and placing it in the position of said third bed.
Claim 17
Dependent Claim
25 words
A water demineralization system comprising: a first column containing a first bed of amine salt of a weakly acidic cation exchange resin of the formula:
Claim 18
Dependent Claim
25 words
A water demineralization system comprising: a first column containing a first bed of amine salt of a weakly acidic cation exchange resin of the formula:
Claim 19
Dependent Claim
23 words
A system according to claim 16 in which the buffer is a secondary or tertiary amine having a molecular weight below about 500.
Claim 20
Dependent Claim
16 words
A system according to claim 16 wherein a mixture of amines is utilized as the buffer.
Claim 21
Dependent Claim
16 words
A system according to claim 16 in which the cation exchange resin contains phosphonic acid groups.
Claim 22
Dependent Claim
23 words
A system according to claim 16 in which the ion-exchange resins are in the form of particles having a mesh size from 20-80.
Claim 23
Dependent Claim
13 words
A system according to claim 16 further including means for regenerating said columns.
Claim 24
Dependent Claim
53 words
A system according to claim 21 further including a fourth spare cation column and a fifth spare anion column, means connecting said first and second columns to said regeneration means when loaded with ions and means for connecting said fourth column as said third column and said fifth column as said second column.
Claim 25
Dependent Claim
42 words
A system according to claim 21 in which a plurality of at least three pairs of cation and anion columns are alternated as pairs in series and one of the lead cation columns of the first pair contains amine buffered cation resin.
Claim 26
Dependent Claim
46 words
A system according to claim 23 further including a spare pair of cation and anion resin columns and means for connecting the first pair to the regeneration means, the second pair to the feed water, and the spare pair to the last pair in said series.
References Cited (Backward Citations)
US2837488A
Cited
US3679580A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-22 | 1979-06-23 | 1979-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-22 | 1983-06-23 | 1983-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-22 | 1987-06-23 | 1987-12-23 | $7700.00 | Window Closed / Lapsed |