Residence time and conversion in the extrusion of chemically reactive materials

Weimin Zhu, Yogesh Jaluria

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


Twin-screw extruders offer improved control of the residence time distribution (RTD) and mixing in materials such as plastics, rubber and food. Based on the flow and the heat transfer characteristics obtained for a self-wiping, co-rotating twin-screw extruder, the residence time and chemical reaction are studied by tracking the particles. For normally starve-fed twin-screw extruders, the length of the completely filled section is calculated as function of the process variables using the coupling of the flow with the die. With a model of the solid conveying section, the RTD for the whole extruder is calculated for corn meal at different screw speeds and flow rates. The calculated variation of RTD with the screw speed and the flow rate yields good agreement with observations from many experiments. The variation of the fully filled section length, chemical conversion and mixing effectiveness are also obtained under different operation conditions. Most of the results are in qualitative agreement with experimental results and may be used as guidelines for extruder design and determination of optimal operating conditions.

Original languageEnglish (US)
Pages (from-to)1280-1291
Number of pages12
JournalPolymer Engineering and Science
Issue number7
StatePublished - Jul 2001

ASJC Scopus subject areas

  • Chemistry(all)
  • Polymers and Plastics
  • Materials Chemistry


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