Diethylenetraiamine Penta Methylenephosphonic Acid As Corrosion Inhibitor for Stainless Steel

Abstract

The protection of metal against corrosion is a major industrial problem. Sulfuric acid newlineis one of the most important industrial chemicals. It has widely used and some part in the newlineproduction of nearly all manufactured goods. The major use of sulfuric acid is in the newlineproduction of fertilizers, e.g., superphosphate of lime and ammonium sulfate. It is largely newlineused in the manufacture of chemicals, e.g., in making hydrochloric acid, nitric acid, sulfate newlinesalts, synthetic detergents, dyes and pigments, explosives, and drugs. It is used in petroleum newlinerefining to wash impurities out of gasoline and other refinery products. Sulfuric acid is used newlinein processing metals, e.g., in pickling (cleaning) iron and steel before plating them with tin newlineor zinc. newlineAll types of seawater desalination plant operate in conditions in which the solubility newlineof calcium carbonate is exceeded with the consequent tendency for precipitation of this newlinecompound as a scale on surfaces such as heat transfer tubes and membranes, it causes newlinesevere corrosion problems which reflect economic loss, loss in efficiency of a machine, newlineshut-down, explosion in pipe lines and so on. To avoid the reductions in performance newlinecaused by scale precipitation, desalination units employ scale control measures which, in newlinerelation to calcium carbonate, take the form of either continuous acid dosing the feed or newlineinvolve the use of scale control inhibitors . The first approach involves removing the newlinecarbonate/bicarbonate ions from the feed prior to entry to the desalination unit. Scale newlinecontrol inhibitors retard the precipitation process and produce a softer deposit which is newlineamenable to removal by mechanical means which include, in multistage flash (MSF) units, newlineperiodic circulation of sponge balls during operation. newlineEven with optimum use of calcium carbonate control measures, the reality is that newlinescale deposits do eventually become established on working surfaces and it is necessary, newlinefrom time to time, to employ a chemical treatment to dissolve the scale. This is done bymeans of an acid cl