Wagon wheels shapes

Katalco), a six-shooter configuration (Topsoe), and a wagon-wheel shape (United Catalysts Inc. Fig. 34). 

Sphere> pellet > trilobe > hollow extrudate > wagon wheel/ minilith The definitive catalyst size selection will be a compromise between high reaction rate (small partiele, exotic shape), low pressure drop (large particle, exotic shape), large crushing strength... 

The carrier can be in the form of a powder used for slurry reactions or a particulate such as a sphere, cylinder, or tablet (typically a few mm in diameter) used in fixed bed reactors. The size and shape depend very much on what is anticipated to be the rate-limiting step. For example, for a reaction limited by pore diffusion it is customary to use a smaller particle in the shape of a star, trilobe, or wagon wheel to decrease the diffusion path while increasing the external geometric surface area. Mechanical strength and solubility... 

Variation of pultrusion producing continuously reinforced products other than profiles. By pulling fibers through a rotation wagon-wheel-type die, curved shapes are formed. Recirculating molds which clamp around the wet fiber package allow continuous forming of various shapes. 

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