Extrusion of Polyethylene Jared Stradley CHEN 4903 December 4, 2006

Extruders

Overview Project objectives Theory Experimental setup and procedures Results Conclusions and Recommendations References Wrap up Q & A

Project objectives Characterize the flow of polyethylene in cylindrical die Estimate the maximum flow rate through a 1” diameter pipe die

Theory Basically, it’s flow through a pipe or an annulus

Theory cont. Major equations Pipe flow:

More theory Annular flow:

Experimental setup

Experimental procedures Ran polyethylene at 155, 160 and 165 °C at 3, 5, 10 and 15 rpm Collected samples of each run Ran polypropylene at 200, 205 and 210 °C at 3, 5, 10 and 15 rpm Also collected samples Calculated Q, and dv/dr

Results

Results cont. Bingham plastic:

Results cont.

Some more results Maximum pressure drop: 6.40 MPa

Final result Maximum velocity possible: cm/s (95% CI)

Conclusion Polyethylene can be extruded at a velocity of cm/s through a 1” cylindrical pipe die (95% CI) This result holds for temperatures between 155 and 165 °C This value compares well with the industrial flow rate of 0.5 m/s

Recommendations Run both Polyethylene and Polypropylene at more temperatures Run both at higher rpm Take samples on same day

References Bird, R. B., W. E. Stewart, E. N. Lightfoot. Transport Phenomena. New York: John Wiley & Sons, Ring, T. A. Fundamentals of Ceramic Powder Processing and Synthesis. San Diego: Academic Press, de Nevers, N. Fluid Mechanics for Chemical Engineers. New York: McGraw-Hill,

Wrap up Project objectives Theory Experimental setup and procedures Results Conclusions and Recommendations References

Questions?