Nalco Chemical Company

Kenneth P Fivizzani

John E Hoots

Claudia C Pierce

Roy I Kaplan

Cynthia A Soderquist

Barbara E Fair

E H Zeiher

A corrosion inhibitor treatment composition for cooling water systems is disclosed in which no chromate is used and no free orthophosphate is present comprising a combination of a localized corrosion inhibitor in the form of a salt of molybdenum, vanadium, or tungsten, a general corrosion and scale inhibitor comprising zinc or nickel, a pair of organic phosphonates, and a stabilizing agent.

Use of molybdate as corrosion inhibitor in a zinc/phosphonate cooling

A method for inhibiting calcium sulfate scale formation and deposition and/or dispersing iron from a feedstream passing through a reverse osmosis system which comprises the steps of: controlling the pH of the feedstream within the range between about 6.0 to about 7.0; controlling the temperature of the feedstream within the range between about 50.degree. to about 80.degree. F.; and adding a scale inhibitor and/or iron disperant to the feedstream in an amount between about 0.002 ppm per ppm hardness (as CaCO.sub.3) of the feedstream to about 0.005 ppm per ppm hardness (as CaCO.sub.3) of the feedstream, the scale inhibitor comprising a water-soluble organic phosphonate and an N-substituted acrylamide polymer containing an amide structure as follows: ##STR1## where R.sub.2 is hydrogen or methyl, R.sub.1 is a hydrogen or an alkyl, and R is alkylene or phenylene and X is sulfonate, (poly) hydroxyl, (poly) carboxyl or carbonyl, and combinations thereof, with the weight ratio of polymer to phosphonate being within the range of about 0.2:1 to about 2:1; provided that when X is sulfonated then R--X-- is selected from the group consisting of sulfomethyl and 2-sulfoethyl.

Method for inhibiting scale formation and/or dispersing iron in reverse

A corrosion inhibitor treatment composition for cooling water systems at elevated temperatures in which no chromate is used is disclosed, comprising a combination of a localized corrosion inhibitor in the form of a salt of molybdenum, vanadium, or tungsten, a reduced level of a general corrosion and scale inhibitor comprising zinc, nickel or a combination thereof, orthophosphate, an organic phosphonate, and a stabilizing agent.

Use of molybdate as a cooling water corrosion inhibitor at higher

The precipitate species of manganese in the presence of an oxidative condition in the waters of an aqueous system can be diminished by treating such waters with certain amide-containing polymer.

Stabilization of manganese in aqueous systems

The present invention is directed to a process for stabilizing iron hydr(oxide) in aqueous systems which comprises adding to an aqueous system in which the water contains or will contain soluble iron a polymer which contains pendant N-substituted amide functionality, including amide substituted with sulfoalkyl wherein the alkyl is of 1 to 3 carbon atoms, sulfophenyl, or such groups substituted further with (poly)hydroxy.

Growing community of inventors

Naperville, IL, United States of America

Kenneth P Fivizzani