North America-based pulp mill equipped with Kraft recovery boiler.
Premature packing wear from normal cycling caused excessive steam leaks in the sootblower feed tubes located in the boiler’s superheater. A solution was needed that would extend the life of the feed tubes and minimize maintenance.
The mill had considered two options:
The customer selected Diamonized® feed tubes from Babcock & Wilcox (B&W).
Diamonized feed tubes provide a surface that is 20% harder than chrome (Rc 66 vs. Rc 52). Unlike chrome or sprayed thermal coatings, Diamonized feed tubes are manufactured using a patented process that creates an abrasion-resistant surface by hardening the metal itself. This process avoids coating or spraying material onto the base metal and, subsequently, prevents coating-related flaking and spawling. Diamonized feed tubes provide a hard surface that can help to extend time between feed tube change-outs, extend packing life and minimize the potential for packing-related steam leaks.
Diamonized feed tubes, installed in April 1997, ran consistently for nearly 10 years. They were removed in February 2007 for inspection, after approximately 70,400 cycles, and were returned to service.
Throughout the life span of the Diamonized feed tubes, savings at the mill were realized in many ways: