An Investigation of a Dryer Can Failure in a Paper Mill

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.