The liquid radial spreading coefficient of packings for absorption and rectification columns is necessary to determine the packing height which ensures uniform liquid distribution over the column cross section. The existing calculation methods can be used theoretically only when this coefficient is independent of the liquid superficial velocity, which is often not the case. A tracer method free from this limitation is developed and tested. The spreading coefficients for different sizes of modern, highly effective packings (Raschig Super-Ring, Ralu-Flow, and impulse metal tower packing) are determined. Practically, in the range of the experimental error, the spreading coefficients of these packings are independent of the liquid superficial velocity. For such packings the tracer method is expected to give the same results as the existing single jet method. Some differences between the results of these two methods are discussed and an explanation is proposed.

Determination of Liquid Radial Spreading Coefficients of Some Highly Effective Packings

This chapter discusses the problem of maldistribution of the liquid and gas phase in packed columns. The chapter also reviews the possibility for the reduction of the liquid and gas phase and takes it into account by the calculations of these apparatuses. Strong maldistribution in packed beds with smaller diameter of the particles is carried out using magnetic resonance imaging for visualization of the packing volume. This method allows visualizing the distribution of the random packing elements and helps to obtain the picture of the velocity components of the flow. Another type of investigation showing the maldistribution of the liquid phase is the determination of the holdup distribution using the gamma tomography method. The experiments are carried out with metal Pall ring 24.4 mm in a 600 mm diameter column, and three types of liquid distributors are used. The third (point source inlet) liquid distributor is used to feed the liquid as a single jet in the centre of the column cross-section.

Chapter 8 – Distribution of the liquid and gas phase over the cross-section of a packed bed column

Prevention of the spreading of the liquid to the walls of column equipment with packings

Zusammenfassung Es wurden Untersuchungen zur experimentellen Bestimmung des Spreitungskoeffizienten bei einer horizontalen Streckmetallplattenpackung in Abhangigkeit von der Durchflussmenge eines Einzelstromes und von den geometrischen Abmessungen durchgefuhrt. Eine dimensionslose Gleichung zur Bestimmung dieses Koeffizienten wird angegeben. Der grosse Wert des Spreitungskoeffizienten empfiehlt diese Streckmetallplatten als Elemente zur Flussigkeitsverteilung.

Alexander Boev

Papers

Bestimmung des Spreitungskoeffizienten bei einer horizontalen Streckmittelpackung