Polymers for the treatment of boiler water
AssigneeBetz Laboratories, Inc.
InventorsFu Chen, Scott M. Boyette, Keith A. Bair
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Abstract
A method for controlling the deposition of scale imparting species on the structural surfaces of steam generating systems comprising the use of a water soluble polymer having the structure ##STR1## wherein E is the repeat unit remaining after polymerization of an alpha, beta ethylenically unsaturated compound. This polymer may also be used in concert with topping agents such as phosphoric acids, phosphonic acids, polyvalent metal salts, metal chelating agents and oxygen scavengers.
Claims28
A method of controlling the deposition of scale imparting precipitates on the structural parts of a system exposed to an aqueous medium containing scale imparting precipitates including calcium, magnesium and iron under steam generating conditions comprising adding to the aqueous medium an effective amount for the purpose of a water soluble polymer having the structure ##STR8## wherein R.sub.1 is H or lower (C.sub.1 -C.sub.4) alkyl, R.sub.2 is (CH.sub.2 --CH.sub.2 --O).sub.n, n is an integer of from about 10 to about 15, R.sub.3 is H, lower (C.sub.1 -C.sub.4) alkyl or an acetate, R.sub.4 is H, R.sub.5 is H, M is H or a water soluble cation, the ratio of c:d being from about 3:1 to about 1:1 and with the water soluble polymer having a chelation value below 200.
The method of 6 wherein the phosphoric acid is a member selected from the group consisting of orthophosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, trimetaphosphoric acid, tetrametaphosphoric acid and water soluble salts thereof.
A method of transporting and removing hardness including calcium, magnesium and iron found in an aqueous medium under steam generating conditions comprising adding to the aqueous medium an effective amount for the purpose of a water soluble polymer having the structure ##STR9## wherein R.sub.1 is H or lower (C.sub.1 -C.sub.4) alkyl, R.sub.2 is (CH.sub.2 --CH.sub.2--O).sub.n, n is a integer of from about 10 to about 15, R.sub.3 is H, lower (C.sub.1 -C.sub.4) alkyl or an acetate, R.sub.4 is H, R.sub.5 is H, M is H or a water soluble cation, the ratio of c:d being from about 3:1 to about 1:1 and with the water soluble polymer having a chelation value below 200.
Dependencies are inferred from the claim text.