Internal corrosion

A recently developed drying appHcation for zeoHtes is the prevention of corrosion in mufflers (52,55). Internal corrosion in mufflers is caused primarily by the condensation of water and acid as the system cools. A unique UOP zeoHte adsorption system takes advantage of the natural thermal cycling of an automotive exhaust system to desorb the water and acid precursors. 

P. J. Grobner, D. L. SponseUer, and D. E. Diesburg, Paper No. 40, in CorrosionI78, International Corrosion Eomm, sponsored by the National Association of Corrosion Engineers, Mar. 1978. 

D. Fyfe and co-workers. International Corrosion Forum Corrosion 75, Paper No. 63, Toronto, National Association of Corrosion Engineers (NACE), Houston, Texas, 1975. 

An interesting and novel use of a soHd desiccant, the reduction of cold condensate corrosion in automotive exhaust systems, illustrates a hybrid closed—open system. Internal corrosion occurs in mufflers when the water vapor in the exhaust condenses after the engine is turned off and the muffler cools. Carbon dioxide dissolves in the condensate to form an acidic soup. In an essentially closed static drying step, an acid- and heat-resistant desiccant located in the muffler adsorbs water vapor from the exhaust gas as it cools to prevent formation of corrosive acidic condensate. When the engine is restarted, the system becomes open, and the desiccant is regenerated by the hot exhaust gas to be ready for the next cooldown step (19). 

If it is assumed that localized or internal corrosion is not present or is recorded separately in the report, the corrosion rate or penetration can be calculated alternatively as... 

Internal Corrosion of Water Distribution Systems, Cooperative Research Report, AWWA Research Foundation, Denver, Colorado, DVGW-Forschungsstelle, 1985. 

Internal corrosion Use appropriate materials of construction in mill can occur, Maintain dry or inert atmosphere in mill at all if feed is high in corrosives, such as halogens, and is hygroscopic. CCPS G-1 CCPS G-23 CCPS G-39 Perry 1984... 

Various electromagnetic and mechanical measuring methods are used to investigate the old well casings to determine whether there is external or internal corrosion. 

Materials of construction depend on the metallurgical requirements and pressure of the gas being compressed hut usually the more popular materials include cast iron, cast steel, alloy steel, or forged steel (high pressure). Figure 12-42 illustrates the extent of damage internally when materials of construction are not resistant to possible effects of internal corrosion. 

Borehole waters are generally very hard and cast iron pipes are still used because of the low internal corrosion rates permitted by the scaling which occurs naturally. Acidic waters cause graphitic attack on cast irons. 

Cotton, J. B., Localised Corrosion 676 NACE International Corrosion Conference series NACE-3 (eds R. W. Stable, B. F. Brown, J. Kruger and A. Agrawal) (1974)... 

The ends of pipe specimens should be closed to prevent internal corrosion. 

A considerable catalyst to the corrosion monitoring market has been expansion in the production of oil and gas, not only in the usual oil areas (US and the Middle East), but also the offshore developments in Europe. In addition to the usual uncertainty of the onset or progress of internal corrosion in the operation of plant, the oil industry has to face the considerable problem concerning prediction of field corrosivity and the possibility of the producing field becoming corrosive or more corrosive as depletion progresses. These factors have considerable influence on the installation of corrosion monitoring as oil and gas production is the major user of such equipment. 

Corrosion Monitoring in Industrial Plants Using Nondestructive Testing and Electrochemical Methods , Proc. Symposium Sponsored by ASTM Committee E-7 and G-1, Montreal, Canada, May 1984, ASTM Special Technical Publication 908 Internal Corrosion Control and Monitoring in the Oil, Gas and Chemical Industries Proc. 

Organic Coatings. Organic coatings or lacquers protect the steel or tin from external or internal corrosion. The can interiors are coated to prevent undesirable reactions between the interior metal surface and the product. These reactions involve (1) corrosion of the tin coating caused by oxidants in the product, (2) color or flavor loss by the product because of metal ion pickup, or (3) staining of the metal by sulfur-con-... 

Domestic heating coil internal corrosion. Where naturally soft or lean city water is supplied and the Langelier Saturation Index (LSI) is below -1.0, acid corrosion takes place as a result of the acidic nature of the water. This water often has a high dissolved gas content, which additionally leads to pinhole corrosion. Where water velocities are too high (say, over 6 ft/s 1.8 m/s) the protective oxide layer is stripped off and erosion corrosion takes place. 

Where RW of basic good quality is supplied as MU for HW heating boilers, no other form of pretreatment is usually necessary. However, an internal, corrosion inhibitor treatment-based program should be provided, and periodic boil-outs may still be necessary. 

Where good control over oxygen and overfeed is exercised, boilers are always clean and the rate of internal corrosion is limited (certainly no worse than for other types of programs). 

Frenier, Wayne E. (Hydrochem Industrial Services). 20 Years of Advances in Technology for Chemically Cleaning Industrial Equipment A Critical Review. Paper 338, presented at the NACE International Corrosion Conference, USA 1998. 

Reardon, P. A. Kelly, J. A. New Oxygen Scavengers and Their Chemistry Under Hydrothermal Conditions. Nalco/NACE International Corrosion Forum, 86. NACE International, USA, March 1986. 

Amine salts of ether carboxylates inhibit internal corrosion of oil storage tanks and pipelines [230]. Furthermore it is possible to use ether carboxylates as corrosion and scale inhibitors for industrial recirculating cooling water systems, metalworking fluids, and hydraulic fluids [28,231-233]. 

A. Legat, in I2th International Corrosion Congress, NACE International, Houston, TX, 1993. 

The normal industrial practice for controlling the internal corrosion of petroleum pipelines is to use coatings, nonmetallic pipeline materials, or corrosion inhibitors. Corrosion inhibitors, which are used for the protection of oil pipelines, are often complex mixtures. 

---