Chemical Engineering Considerations in Zeolite Forming

The speed of provision of the feed molecules to the adsorption/catalytic sites must be balanced with engineering issues such as pressure drop in a reactor/ adsorber, so the parhcle size and pore structure of engineered forms must be optimized for each appHcation. A hierarchy of diffusion mechanisms interplays in processes using formed zeoHtes. Micropore, molecular, Knudsen and surface diffusion mechanisms are all more or less operative, and the rate Hmifing diffusion mechanism in each case is directly affected by synthesis and post-synthesis manufacturing processes. Additional details are provided in Chapter 9. 

Zeolite particles are incorporated into a number of different engineered forms, including smaU spherical parhcles for fluidized bed appHcations and smaU granules for powdered detergents. Larger forms include extruded peUets with various cross-sectional shapes and beads made by bead-forming processes. 

Zeolite catalysts and adsorbents have also been incorporated into monolithic contactors by several routes, including extruded zeoHte/binder composites [70], wash-coated ceramic monoliths [71] and corrugated thin-sheet monoliths [72]. 

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