Modifications to Structured Packings to Increase Their Capacity
The hydraulic performance of structured packed columns is characterized by parameters such as loading point, flooding point, and dry and wet pressure-drop. These parameters can be positively influenced by optimizing the transition areas between two adjacent packing layers. Tests have been done in a two-phase test rig with a rectangular column made of perspex. The test medium is a liquid hydrocarbon in counterflow to saturated nitrogen gas. The performance of different packing structures at the layer-to-layer transition zone and the addition of vane-type elements between two packing layers was evaluated. Several packing modifications were tested and the results were compared with those of a non-modified packing. The intentions of this work are: to rank the modifications of structured packings with respect to the achieved capacity increase; to determine whether flooding is initiated in the core of the corrugated packing or in the transition area in spite of the modifications made on the lower or top side of the packing sheets; and to find out how the loading point is influenced by the modifications.
Prozessintensivierung in der Fluidverfahrenstechnik
Prozessintensivierung verfolgt im Wesentlichen vier verschiedene Ziele: die Effizienz von intra- und intermolekularen Wechselwirkungen maximieren, den Durchlauf einheitlicher Prozesswege fur jedes Molekul sicherstellen, Triebkrafte und Phasengrenzflachen optimieren und Synergieeffekte zwischen Teilprozessen maximieren. Jedes dieser Ziele kann auf insgesamt vier fundamentalen Ebenen erreicht werden: auf einer raumlichen, thermodynamischen, zeitlichen und funktionalen Ebene. Der vorliegende Artikel gibt eine Ubersicht, wie sich die Ziele der Prozessintensivierung in der Fluidverfahrenstechnik erreichen lassen. Dabei wird jede der vier Ebenen separat uber alle relevanten Zeit- und Langenskalen hinweg von den Molekulen bis hin zur verfahrenstechnischen Anlage betrachtet. 
 
 
 
Process intensification follows four main goals: to maximize the effectiveness of intra- and intermolecular events, to give each molecule the same processing experience, to optimize the driving forces/maximize specific interfacial areas, and to maximize the synergistic effects of partial processes. These goals can be achieved in four domains: spatial, thermodynamic, temporal and functional. The paper shows how these goals can be reached in fluid separation processes. In doing so, each of the four domains are examined separately moving across all relevant time and length scales, from the molecules to the processing unit plant.
Damage initiation and propagation in composite shells subjected to impact
Abstract The paper investigates the impact-induced damage initiation and propagation for laminated composite shells under low-velocity impact. A three-dimensional eight-node non-conforming element is described to analyze interlaminar stress distribution, and progressive failure. The damage analysis is performed by using Tsai–Wu quadratic failure criterion, Tsai’s damage modes and an additional delamination formula at all Gaussian points. The damage modes considered are matrix cracking, fiber breakage and delamination. The progressive failure is expressed by reducing stiffness of the material at all failed Gaussian points. Special attention is centered on curved laminates. Impact energy threshold for the onset of damage and transient damage size are predicted for composite shells. The analyses of the flat and curved laminates are compared for discussing their different damage mechanism. In addition, the influence of the stacking sequence, the thickness and the radius of curvature on damage behavior of composite shells are studied.