Enhanced galvanized corrosion inhibitor

Abstract

The corrosion inhibiting activity of quaternary ammonium compounds is enhanced by the addition of a carbamide, specifically urea. In particular, the arylquinolinium halide corrosion inhibitor's activity with respect to a galvanized surface is significantly enhanced by the addition of the urea.

1 . A method of removing scale on a surface comprising applying to said surface an acidic composition comprising an acid, a quaternary ammonium corrosion inhibitor and a water soluble carbamide.  
     
     
         2 . The method claimed in  claim 1  wherein said quaternary ammonium compound is an arylquinolinium halide.  
     
     
         3 . The method claimed in  claim 2  wherein said aryl quinolinium halide is 1-benzylquinolinium halide.  
     
     
         4 . The method claimed in  claim 1  wherein said carbamide is urea.  
     
     
         5 . The method claimed in  claim 1  wherein said acid is selected from the group consisting of lactic acid, sulfamic acid, glycolic acid, citric acid, hydrochloric acid, phosphoric acid and methane sulfonic acid.  
     
     
         6 . The method claimed in  claim 1  wherein said surface is on a boiler and said acidic composition is circulated through said boiler.  
     
     
         7 . The method claimed in  claim 1  wherein said surface is on a cooling tower and said acidic composition is circulated through said cooling tower.  
     
     
         8 . A corrosion inhibitor comprising an aryl quaternary ammonium compound in combination with urea.  
     
     
         9 . The composition claimed in  claim 8  wherein the ratio of quaternary ammonium compound to urea is from 1:3 to 3:1 by weight.  
     
     
         10 . The composition claimed in  claim 9  wherein said quaternary ammonium compound is an arylquinolinium halide.  
     
     
         11 . The composition claimed in  claim 9  wherein said quaternary ammonium compound is 1-benzylquinolinium halide.  
     
     
         12 . The composition claimed in  claim 8  further comprising an acid.  
     
     
         13 . The composition claimed in  claim 14  further comprising a thickening agent.  
     
     
         14 . The method of preventing corrosion on a galvanic surface comprising applying to said galvanic surface a composition comprising 1-benzylquinolinium chloride in combination with urea.  
     
     
         15 . The method claimed in  claim 1  wherein said ratio of 1-benzylquinolinium chloride to urea is from about 1:3 to 3:1 by weight.  
     
     
         16 . A method of removing white rust from galvanized surfaces of a cooling tower comprising draining water from said cooling tower, applying an acidic gel to said galvanic surfaces for a period of time sufficient to dissolve said white rust wherein said acidic gel comprises a gelling agent, and acid and a corrosion inhibitor.  
     
     
         17 . The method claimed in  claim 16  wherein said corrosion inhibitor comprises a quaternary ammonium compound in combination with urea.  
     
     
         18 . The method claimed in  claim 17  wherein said quaternary ammonium compound is benzylquinolinium halide.  
     
     
         19 . The method claimed in  claim 18  wherein the ratio of urea to benzylquinolinium halide is from 1:3 to about 3:3 by weight.  
     
     
         20 . The method claimed in  claim 19  further comprising rinsing said acidic gel from said galvanic surface.  
     
     
         21 . A gel for removing white rust comprising an acid, an acid thickener, urea and a quaternary ammonium compound.  
     
     
         22 . The composition claimed in  claim 21  wherein said quaternary ammonium compound comprises an arylquinolinium halide.  
     
     
         23 . The composition claimed in  claim 22  wherein said arylquinolinium halide is a benzylquinolinium halide.  
     
     
         24 . The composition claimed in  claim 23  wherein the ration of urea to benzylquinolinium halide is from 1:3 to 3:3 by weight.