Heat exchangers: 'bye to gaskets and welds'
24 Jun 2006
Alfa Laval is stepping up the commercial introduction of its AlfaNova plate heat exchanger technology, which "says goodbye" to gaskets and welds, according to Johan Gunnarsson, marketing manager Alfa Laval Lund AB.
"We are just at the start of a very important development based on this technology," said Gunnarsson, who described AlfaNova as a unique all-stainless steel system employing a heavily patented technology.
The units employ a bonding system called AlfaFusion, in which a chemically-modified steel filler at each contact point of the steel plates is heated to 1,100 degrees C. The bonds can withstand highly aggressive conditions, pressures up to 30 bar and temperatures up to 550 degrees C.
The filler contains a special modified steel that melts below the melting point of the plate steel and chemically fuses into the substrate plate, explained Gunnarsson. The joint, he said, is "similar" to a weld in terms of both its chemical and mechanical properties.
Alfa Laval has already sold the units to major petrochemical companies, said Gunnarsson, who listed BASF, Bayer and Dow Chemical among the early customers. Typical uses include organic solvents, thermal oil, biodiesel, high temperature water, liquid nitrogen and bioreactors, he said.
Gunnarsson also cited how a Korean epoxy resin manufacturer is employing the system on a line containing epichlorohydrin, which eliminated the option of using gaskets. The technology is also suitable for certain food and pharmaceutical industry applications where copper and nickel cannot be used due to health or environmental concerns.
The absence of welding and other fastening requirements mean the Alfa Nova is more cost effective to manufacture, though the capital investment costs of the heating furnace limit the size. The company has supplied units in five sizes, the largest at 200m3/hr, said Gunnarsson.
