Process condenser, tube leak

This is a problem in process plant steam heaters. There are always some residual carbonates in boiler feed water. When the water is turned into steam, some of these carbonates decompose into CO Thus, all steam is contaminated with CO. The CO being far more volatile than water gets trapped and accumulates in the high points of steam heaters. With time, the CO condenses in the water to form carbonic acid. This causes corrosion and tube leaks. To avoid CO accumulation, the exchanger high points can be vented. 

Air-cooled condensers are especially attractive at locations where water is scarce or expensive to treat. Even when water is plentiful, air coolers are frequently the more economical alternative. Elimination of the problems associated with the water side of water-cooled equipment, such as fouling, stress-corrosion cracking, and water leaks into the process, is an important advantage of air-cooled equipment. In many cases, carbon steel tubes can be employed in air-cooled condensers when more expensive alloy tubes would otherwise have been necessary. The use of air-cooled heat exchangers may eliminate the need for additional investment in plant cooling water facilities. 

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