US4118318A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gas scrubber scale and deposit control
Assignee: ECC SPECIALTY CHEMICALS Inc
•
Filing: 1977-09-22
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Granted: 1978-10-03
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Expires: 1997-09-22
Abstract
Abstract Use of a high molecular weight polymer and a scale inhibitor to control deposit build-up in gas scrubbers.
Inventors
- 👤 Gerald Elvin Welder
- 👤 Edward Russell Lang
- 👤 Charles Wilmer Slagle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:46
CPC Classifications
C; C08; C08L; C08L25/00; C08L25/18; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/14; C02F5/145; C09; C09D; C09D133/00; C09D133/24; C09D133/26
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
173 words
A composition useful for controlling deposit build-up in gas scrubbers consisting essentially of a scale inhibitor selected from the group consisting of: a. phosphonates of the general formula: ##STR5## wherein R is ##STR6## M is H, NH 4 , alkali metal or combinations thereof; N is 0 to 6; and x is 1 to 6; b. phosphonates of the general formula: ##STR7## wherein X is -- OH or -- NH 2 and R is an alkyl group of from 1 to 5 carbon atoms; and c. sodium polyphosphates and phosphate esters of the formula: N [ROPO.sub.3 M.sub.2 ].sub.3 wherein M may be -- H, -- NH 2 or a monovalent metal ion and R is an alkylene group having from 1 to 18 carbon atoms; and at least one water-soluble polymer selected from the group consisting of polyacrylamides, poly(2-acrylamido methyl propane sulfonic acid) and sulfonated polystyrenes, said polymer having a molecular weight of at least 25,000 wherein the ratio of scale inhibitor to polymer is from about 1:10 to about 10:1 by weight.
Claim 2
Dependent Claim
173 words
A composition useful for controlling deposit build-up in gas scrubbers consisting essentially of a scale inhibitor selected from the group consisting of: a. phosphonates of the general formula: ##STR5## wherein R is ##STR6## M is H, NH 4 , alkali metal or combinations thereof; N is 0 to 6; and x is 1 to 6; b. phosphonates of the general formula: ##STR7## wherein X is -- OH or -- NH 2 and R is an alkyl group of from 1 to 5 carbon atoms; and c. sodium polyphosphates and phosphate esters of the formula: N [ROPO.sub.3 M.sub.2 ].sub.3 wherein M may be -- H, -- NH 2 or a monovalent metal ion and R is an alkylene group having from 1 to 18 carbon atoms; and at least one water-soluble polymer selected from the group consisting of polyacrylamides, poly(2-acrylamido methyl propane sulfonic acid) and sulfonated polystyrenes, said polymer having a molecular weight of at least 25,000 wherein the ratio of scale inhibitor to polymer is from about 1:10 to about 10:1 by weight.
Claim 3
Dependent Claim
15 words
A composition as in claim 1 wherein the scale inhibitor is amino tris (methylene phosphonate).
Claim 4
Dependent Claim
24 words
A composition as in claim 1 wherein the polymer is a copolymer of acrylamide and 2-acrylamido methyl propane sulfonic acid or its water-soluble salts.
Claim 5
Dependent Claim
12 words
A composition as in claim 1 wherein the polymer is a polyacrylamide.
Claim 6
Dependent Claim
12 words
A composition as in claim 1 wherein the polymer is sulfonated polystyrene.
Claim 7
Dependent Claim
13 words
A composition as in claim 1 wherein the scale inhibitor is a polyphosphate.
Claim 8
Dependent Claim
12 words
A composition as in claim 6 wherein the polyphosphate is sodium hexametaphosphate.
Claim 9
Dependent Claim
44 words
A composition as in claim 1 wherein the scale inhibitor is a phosphonate of the formula: ##STR8## wherein X is -- OH or -- NH 2 and R is an alkyl group of from 1 to 5 carbon atoms, or a water-soluble salt thereof.
Claim 10
Dependent Claim
19 words
A composition as in claim 8 wherein the scale inhibitor is hydroxyethylene-1, 1-diphosphonic acid or a water-soluble salt thereof.
Claim 11
Dependent Claim
53 words
A composition useful for controlling deposit build-up in gas scrubbers consisting essentially of amino tris (methylene phosphonate) and a copolymer of acrylamide and 2acrylamido methyl propane sulfonic acid or its water-soluble salts having a molecular weight of at least 250,000 wherein the weight ratio of phosphonate to polymer is from 1:5 to 5:1.
Claim 12
Dependent Claim
53 words
A composition useful for controlling deposit build-up in gas scrubbers consisting essentially of amino tris (methylene phosphonate) and a copolymer of acrylamide and 2acrylamido methyl propane sulfonic acid or its water-soluble salts having a molecular weight of at least 250,000 wherein the weight ratio of phosphonate to polymer is from 1:5 to 5:1.
Claim 13
Independent Claim
186 words
A method of controlling deposit build-up in gas scrubbers which comprises maintaining in the aqueous scrubbing medium at least 0.01 ppm of a composition consisting essentially of a scale inhibitor selected from the group consisting of: a. phosphonates of the general formula: ##STR9## wherein R is ##STR10## M is H, NH 4 , alkali metal or combinations thereof; n is 0 to 6; and x is 1 to 6; b. phosphonates of the general formula: ##STR11## wherein X is -- OH or -- NH 2 and R is an alkyl group of from 1 to 5 carbon atoms; and c. sodium polyphosphates and phosphate esters of the formula: N[ROPO.sub.3 M.sub.2 ].sub.3 wherein M may be -- H, -- NH 2 or a monovalent metal ion and R is an alkylene group having from 1 to 18 carbon atoms; and at least one water-soluble polymer selected from the group consisting of polyacrylamides, poly(2-acrylamido methyl propane sulfonic acid) and sulfonated polystyrenes, said polymer having a molecular weight of at least 250,000, wherein the ratio of scale inhibitor to polymer is from about 1:10 to about 10:1 by weight.
Claim 14
Independent Claim
186 words
A method of controlling deposit build-up in gas scrubbers which comprises maintaining in the aqueous scrubbing medium at least 0.01 ppm of a composition consisting essentially of a scale inhibitor selected from the group consisting of: a. phosphonates of the general formula: ##STR9## wherein R is ##STR10## M is H, NH 4 , alkali metal or combinations thereof; n is 0 to 6; and x is 1 to 6; b. phosphonates of the general formula: ##STR11## wherein X is -- OH or -- NH 2 and R is an alkyl group of from 1 to 5 carbon atoms; and c. sodium polyphosphates and phosphate esters of the formula: N[ROPO.sub.3 M.sub.2 ].sub.3 wherein M may be -- H, -- NH 2 or a monovalent metal ion and R is an alkylene group having from 1 to 18 carbon atoms; and at least one water-soluble polymer selected from the group consisting of polyacrylamides, poly(2-acrylamido methyl propane sulfonic acid) and sulfonated polystyrenes, said polymer having a molecular weight of at least 250,000, wherein the ratio of scale inhibitor to polymer is from about 1:10 to about 10:1 by weight.
Claim 15
Dependent Claim
12 words
A method as in claim 11 wherein the polymer is sulfonated polystyrene.
Claim 16
Dependent Claim
12 words
A method as in claim 11 wherein the polymer is a polyacrylamide.
Claim 17
Dependent Claim
24 words
A method as in claim 11 wherein the polymer is a copolymer of acrylamide and 2-acrylamido methyl propane sulfonic acid or its water-soluble salts.
Claim 18
Dependent Claim
15 words
A method as in claim 11 wherein the scale inhibitor is amino tris (methylene phosphonate).
Claim 19
Dependent Claim
44 words
A method as in claim 11 wherein the scale inhibitor is a phosphonate of the formula: ##STR12## wherein X is -- OH or -- NH 2 and R is an alkyl group of from 1 to 5 carbon atoms, or a water-soluble salt thereof.
Claim 20
Dependent Claim
19 words
A method as in claim 16 wherein the scale inhibitor is hydroxyethylidene-1, 1-diphosphonic acid or a water-soluble salt thereof.
Claim 21
Dependent Claim
12 words
A method as in claim 11 wherein the polyphosphate is sodium hexametaphosphate.
Claim 22
Dependent Claim
13 words
A method as in claim 11 wherein the scale inhibitor is a polyphosphate.
References Cited (Backward Citations)
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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) | 1981-10-02 | 1982-04-03 | 1982-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-10-02 | 1986-04-03 | 1986-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-10-02 | 1990-04-03 | 1990-10-03 | $7700.00 | Window Closed / Lapsed |