CARILON pellets are manufactured by Shell, and are then melted in an extruder for injection processing, blow molding, and pipe and film extrusions. CARILON cannot sustain very high temperatures for long periods of time during processing because the pellets' physical properties degrade. This results in a shutdown of the production line. Shell engineers observed that during pelletizing, temperature and property differences were indeed occurring, which could adversely affect the process.

Twin-screw extruder temperature contours

"For each plant now producing CARILON, we evaluate savings realized, thanks to numerical simulation, to about $1,000,000 per year, in reduced maintenance and scrap reduction."
Loek Vreenegoor
Shell

Fluent CFD software was used to simulate the flow in the region from the extruder to the pelletizer. A solution proposed from the study was to add mixing capabilities at the screw tip to homogenize CARILON's material properties.

These simulations proved to be accurate and Shell was able to quickly reduce the number of redesigns in the process. Each redesign normally led to a fixed cost of $200,000 plus $100,000 per day of lost production.

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