Tracking pellet motion in a wurster coater using positron emission

Research output: Contribution to conference (unpublished)Paperpeer-review


External organisations

  • Department of Chemical Engineering
  • Merck Sharp and Dohme Ltd.
  • Positron Imaging Centre


The PEPT technique has been used to study pellet motion within the Wurster coater. Experiments were undertaken to study the effect of batch size, partition gap and fluidising air flow rate on mean particle cycle time, the distribution of particle cycle times, solids circulation rate and pellet trajectories. The results revealed interesting features relating to pellet motion, particularly, the zones of internal solids circulation within the upper and lower regions of the draft tube under certain design and operating conditions, which could potentially contribute to non-uniformity of pellet coating. This study demonstrates that there is a narrow operating window in which the Wurster coater can operate to deliver uniform pellet motion. Changing any one of the parameters of batch size, partition gap and fluidisation air flow alters the distribution of air flow between the draft tube and annulus which consequently alters the magnitude and pattern of solids flow through the partition gap.


Original languageEnglish
Publication statusPublished - 1 Dec 2006
Event2006 AIChE Spring National Meeting - 5th World Congress on Particle Technology - Orlando, FL, United States
Duration: 23 Apr 200627 Apr 2006


Conference2006 AIChE Spring National Meeting - 5th World Congress on Particle Technology
CountryUnited States
CityOrlando, FL


  • Pellet trajectories, PEPT, Solids circulation rate, Wurster coater