Abstract: Adsorbents and methods for the adsorptive separation of para-xylene from a mixture containing at least one other C8 aromatic hydrocarbon (e.g., a mixture of ortho-xylene, meta-xylene, para-xylene, and ethylbenzene) are described. Suitable binderless adsorbents (e.g., formulated with the substantial absence of an amorphous material that normally reduces selective pore volume), particularly those with a water content from about 3% to about 5.5% by weight, improve capacity and/or mass transfer. These properties are especially advantageous for improving productivity in low temperature, low cycle time adsorptive separation operations in a simulated moving bed mode.

Abstract: A drum has a polygonal shell section and a round shell section interconnected to one another to mutually define a resonant chamber. A drum head connects to the round shell section, such as by seating on a drum wall of optionally adjustable height. Acoustic properties of the drum are enhanced by the polygonal section, and can be further influenced by providing a bass port. The bass port can have an adjustable position relative to the resonant chamber to thereby influence the coupling of acoustic waves and their transmission through the bass port.