An Investigation of a Dryer Can Failure in a Paper Mill

Abstract

The failure of a rotary dryer in a paper manufacturing facility is reported and analyzed. The primary cause of failure is identified as a weakened structure and as a consequence, inlet pressure of the steam into the dryer reaching a critical limit. Post failure, the shell, and the two heads of the dryer were analyzed using characterization techniques such as stereomicroscopy and scanning electron microscopy with energy dispersive analysis. The threads of the shell were found completely chipped off. In the microchemical analysis, silicon in the form of quartz was found inside the shell at the threads. Silica in the form of quartz is theorized as having entered through the steam and becoming entrapped in the gaps of the threaded connections. Although wear between brittle shell and the connecting bolts can potentially develop torsion and lead to the chipping off of the crest regions of the threads over the time, the deposition of silica might have instigated and aggravated the same.