Packed columns liquid redistribution

Packed columns must be provided with good initial distribution of liquid across the column cross section and redistribution of liquid at various height intei vals that decrease with increasing column diameter. A wide variety of distributors and redistributors are available. Packed columns should be considered when ... 

Internal uniform distribution Properly designed devices to distribute and redistribute liquid entering the column is critical to obtain best performance of these types of packings. 

The height of the column for a packed column needs to allow for liquid distribution and redistribution. As the feed enters the column, the liquid above the feed needs to be collected, combined with the feed liquid and distributed across the packing below the feed using troughs,... 

Liquid redistributors are installed at frequent intervals in a packed column to remix the liquid, thus counteracting the propagation of maldistribution effects and the natural tendency of liquid to migrate toward the wall. A common design practice is to redistribute the liquid every 20 ft (6-7 m). 

Liquid Distribution Good initial distribution is not as essential in a sieve tray extractor as it is in a packed extractor, since the trays provide redistribution. While the same distributors used in packed columns are... 

Liquid redistributors are used wherever an intermediate liquid feed is introduced into a packed column, and between packed sections, wherever liquid redistribution is required. 

In packed columns, chimney trays are the most effective liquid collection devices for high liquid flow rate services, for interreboilers, and for once-through reboilers. They are also sometimes used for collecting liquid from an upper bed for redistribution (when the redistributor is not self-collecting), and as vapor distributors. 

For fast reactions, change in the flow regime has dramatic effects on performance. Prevent foaming. Liquid distributor design is very important. Carefully plan the liquid redistribution along the walls for columns < 2-3 m diameter. For these small columns place redistributors at distances = 8-10 times the column diameter. The critical surface tension of the solid packing should be greater than the surface tension of the liquid to ensure that the liquid film remains intact in a packed contactor. 

A basic requirement for the proper functioning of a packed column is that its diameter should be at least ten times the nominal size of the packing (see Table 5.6) to ensure adequate distribution of the gas and, particularly, the liquid. Redistribution sections, in which the liquid down-flow is collected and redistributed over entire tower cross sections, are often inserted to ensure good performance. On the other hand, the tower cannot be too large for structural and economic reasons. A normal diameter range is 0.5 to 5 m, but diameters as high as 14 m have been reported. 

The one-piece distributor VSTG is us in hi ly corrosive substances. It uses tubes with lateral outlets to distribute the liquM onto the packing. It can be installed in flanged column only. The device can be used to collect and redistribute liquids between packed s ons. Hereafter its specifications are presented. 

Redistributors are used to collect liquid that has migrated to the column walls and redistribute it evenly over the packing. They will also even out any maldistribution that has occurred within the packing. 

Since liquid maldistribution may become a problem unless the flow is periodically redistributed in a tall column, the total packing height must be broken up into a number of individual beds ... 

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