Cooling water, corrosion inhibitors carbonization

Alkyl or aryl phosphonates, which contain a carbon—phosphoms bond, are comparatively more stable. They are of interest as antiscaling additives and corrosion inhibitors for cooling towers and heat exchangers (see Dispersants Water, industrial water treatment), surfactants (qv), sequestrants, and textile-treating agents. Trialkyl phosphites are usehil as esterification (qv) reagents. 

In our plant, an overhead water-cooled condenser has a shell of carbon steel and tubes of admiralty brass, and handles a sour hydrocarbon stream, in the shell. The tube bundle suffered general corrosion and wear on its outside surface and required replacement every two years, for the past 16 years. This despite the use of a recommended corrosion inhibitor. 

Earlier the standard industrial approach to prevention of calcium carbonate scaling by addition of sulfuric acid was described. Objectives were to reduce bicarbonate alkalinity, convert calcium carbonate to calcium sulfate, and regulate sulfate concentration by bleedoff. Corrosion inhibitors were added to protect system metals. A new approach to industrial cooling system treatment does not require addition of sulfuric acid. It involves application of phosphonate seques-trants, dispersants and special corrosion inhibitors, and provides deposit control equal to that obtainable when using sulfuric acid. Availability of phosphonate sequestrants makes possible combination scale control and corrosion inhibitors that can be used without the necessity of reducing cooling water alkalinity by acid feed. 

C. Piping and Instrumentation. Cooling water piping is usually carbon steel. This fact makes it essential for the plant operator to keep up with the water treatment program. Untreated cooling water is the most corrosive form. Most plants at least add inhibitors. These vary in composition, and it is difficult to generalize other than to say that chromates, once a standard, are now seldom used, because of their toxicity. 

Uses Sequestrant, deflocculant, threshold inhibitor in cooling water treatment stabilizer for biocides such as chlorine and bromine dispersant for scale formation corrosion inhibitor for carbon steel... 

Uses Corrosion inhibitor and deposit control agent in cooling water treatment preventing the development and accumulation of calcium carbonate, sulfate and phosphate scales... 

Uses Dispersant and sequestrant for treatment of boiler feed water and cooling tower water sludge conditioner suspends carbonate and phosphate sludges corrosion inhibitor mild oxygen scavenger scale inhibitor in boiler water treatments, industrial cleaners Features Protects against oxygen corrosion... 

Chem. Descrip. Polyacrylates and polymaleic polymers Uses High performance scale and deposit control agents for boiler and cooling water systems provides effective scale control over wide range of pH, temp., and hardness ranges effective with both hard or soft feedwaters provides protection from calcium carbonate and calcium sulfate exc. dispersant for calcium phosphate, iron oxides, and other inorg. solids designed to be used in conjunction with corrosion inhibitors... 

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