Scale control in aqueous systems
AssigneeW. R. Grace & Co.-Conn.
InventorDionisio Cuisia
Life of this patent
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Abstract
A composition and process for preventing the deposition of scale and sludge in aqueous systems comprising adding to the system the combination of three or more additives selected from the group consisting of a) polyacrylic acid, copolymer of alkylsulfonate and maleic anhydride and mixtures thereof, b) hydroxy ethylidene diphosphonic acid, amino (trimethyl phosphonic acid), diethylenetriamine pentaacetic acid, and mixtures thereof, and c) copolymer of styrene sulfonate and maleic anhydride, copolymer of acrylic acid and acrylamide, poly(acrylic acid-co-hypophosphite) and mixtures thereof, and wherein the combination contains at least one additive selected from each of a), b) and c).
Claims8
A method for inhibiting the deposition of scale and sludge in aqueous systems comprising adding to the aqueous system a composition containing at least three additives selected from the group consisting of;
- (a) polyacrylic acid (PAA) having a molecular weight from 1,000 to 90,000, copolymer of allyl sulfonate and maleic anhydride (ASMA) having a molecular weight of from 1,000 to 10,000 and a monomer weight ratio of 1:10 to 10:1 and mixtures thereof,
- (b) hydroxyethylidene diphosphonic acid (HEDPA), amine(trimethylene phosphonic acid) (AMP), diethylenetriamine pentaacetic acid (DTPA), and
- (c) copolymer of acrylic acid and acrylamide (AAA) having a molecular weight of from 2,000 to 5,000 and a monomer weight ratio of 1:10 to 10:1, and wherein the composition contains at least one additive selected from each of (a), (b) and (c) supra in ration of a:b:c in the range (6-2):(6-2):(3- 1) respectively on a weight basis, and in an amount effective to inhibit the deposition of scale.
Dependencies are inferred from the claim text.