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Edward Lowton
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Tube life boosted
27 February 2015
A Caribbean producer of furfural, an organic compound derived from agricultural byproducts, has replaced the tube in its heat exchangers with hyper-duplex stainless steel by Sandvik Materials Technology. As a result, tube lifecycles have extended from two to 15 years, with a profound impact on material costs.
The plant, based in the Dominican Republic, experienced problems with the lifecycles of existing standard stainless steel tube in several of its heat exchangers, used to process untreated seawater as the cooling media. In some cases the tube needed replacing after just two years.
Sandvik SAF 2707 HD tubes were installed in two overhead heat exchangers. Replacement material was installed in a distillation column that condenses furfural acid and low boiling components.
The tubes are a hyper-duplex stainless steel with excellent resistance to pitting corrosion and chloride induced stress corrosion cracking. The material is an alternative to nickel alloys with similar performance, but is said to be more attractive economically in terms of material and life cycle costs.
After two years of successful operation, the heat exchangers were inspected and found to be as good as new, showing no signs of pitting corrosion. The furfural producer will introduce periodic washing of metal surfaces to keep the equipment free from seawater debris.
