Sandvik Materials Technology supplied its Sandvik Sanicro™ 28 composite tubes to a eucalyptus pulp mill in Uruguay.
An important part of the pulp production process involves the use of superheater panels manufactured from composite steel tubes, which are used with chloride within the pulp bleaching process. Accumulations of the chemical, in conjunction with the high temperatures involved, were having a detrimental effect on the existing carbon steel tubes. Andritz, fabricators of pulp and paper equipment, was brought in to undertake a replacement project of the original superheater equipment. The company carried out a full evaluation of the site and processes and carefully examined the previous carbon steel tube usage. Computer modelling was then used to seek the best solution and to recommend an alternative solution for the mill.
Photo courtesy of Sandvik
Based upon the findings of the evaluation and Andritz’s previous experience with Sandvik products, the decision was taken to select Sandvik Sanicro™ 28 composite tubes for the superheaters. Sandvik SanicroTM 28 is a high alloy, multi-purpose austenitic stainless steel, developed especially for use in highly corrosive conditions. Offering good weldability, its characteristics include high resistance to strong acids, resistance to stress corrosion cracking and pitting and crevice corrosion, as well as intergranular corrosion in certain environments.
One year after the installation, Andritz has reported there are no defects or corrosion damage found in the composite tubes.
