Commercial zeolites drying and recovery in a Vacuum Membrane Dryer (VMDr)

In this work, the use of a Vacuum Membrane Dryer (VMDr) was proposed as alternative to freeze drying for dehydrating engineered zeolites. Experiments on three types of zeolite suspensions (5 wt%) were carried out at lab scale by varying the temperature, the vacuum pressure and the quantity of suspension to treat. In all tests, it was possible to achieve, at different operating times, a final solid content of about 90 wt% together with a permeate solid-free (100% solid recovery). Moreover, preliminary granulometry data were in good agreement with those obtained by freeze drying. Based on the experimental results, the operating time and the membrane area required to dehydrate the typical volumes of slurries produced by the Company were calculated. Finally, next steps needed to further assess the VMDr performance and to move towards its scale-up were reported and discussed.