In the article, presented are sufficient and necessary conditions for a class of functions involving the ratio of two gamma functions to be logarithmically completely monotonic. From this, some inequalities for bounding the ratio of two gamma functions are refined, extended and sharpened readily, and double inequalities on the divided differences of the psi and polygamma functions are derived s...

The successful revamp of a conventional tray Xylenes Distillation Column (3800 mm / 4300 mm diameter) is described. The column takes a xylene side-stream from reformate to feed an aromatics plant to make higher value products. Changing the column configuration to a Dividing Wall Column (DWC) resulted in improved product purity and significant energy savings. The project cycle is detailed includ...

This presentation examines the procedures involved in implementing the divided-wall column technology for processing petrochemical cuts. Special simulation tools have been developed for the design of the overall column configuration and an evolutionary algorithm is used to find the optimum column design based on the total annual costs. Practical operation is verified on a laboratory scale with ...