Heat transfer agents, corrosion

Corrosion of iron-base and nickel-base alloys by liquid metals used as heat transfer agents (e.g., liquid sodium, potassium, and lithium)... 

Initially, in spite of its complexity, the Houdry process hardware worked satisfactorily. However, the steam cooling tubes were subjected to severe conditions so that after about two years corrosion was sufficiently severe to allow water to contact the catalyst. The steam reacted with the catalyst during regeneration, resulting in severe declines in activity. To overcome this problem, the water/steam fluid was replaced with molten salt to cool the tubes in the case and to act as an intermediate heat transfer agent from the case to the steam generators. This invention has been credited to Socony-Vacuum (27). 

Use antifouling agents and corrosion inhibitors in heat transfer systems... 

The corrosion rate of nickel in sodium hydroxide is adversely affected by heat transfer by small amounts of oxidisable alkaline sulphur-containing salts, e.g. Na2SOj, NajS Oj, Na S and, at high temperatures, by alkaline oxidising agents, viz. NaClOj and NajOj. In the former circumstance Alloy 600 is more resistant than nickel, but not in the latter. When Alloy 600 is used for service in caustic alkalis, it should be stress relieved after fabrication to minimise the possibility of stress-corrosion cracking. 

Use Corrosion inhibitor in alcohol-base antifreezes and water-cooled reactors. Oxidizing agent for organic material, especially in the presence of light heat-transfer medium. 

Uses Sec. plasticizer for vinyl wire rope lubricant heat transfer fluid solvent for oil-sol. sulfonates such as sacrificial agent corrosion inhibitors specialty lubricants sulfonation feedstock intermediate for agric. emulsifiers, enhanced oil recovery surfactants, dust abatement agents... 

Uses Dispersant and stabilizer for cooling water programs, maintaining exc. heat transfer and low corrosion rates in the system antisealant agent stabilizer for corrosion inhibitors such as phosphate and zinc controls boiler sludge dispersant for particulate matter containing calcium, iron, and kaolin, and prevents their adhesion to heat transfer surfaces prevents precipitation of phosphonates Features U.S. patent4,711,725... 

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