Liquid collector

Figure 11. Liquid collector plate. (Courtesy of Norton Chemical Process Products Corporation.)...

Figure 11 shows a t pical liquid collector plate for a column that uses one side downcomer to withdraw the liquid. The maximum diameter for such a design is about 12 ft, which is limited by the hydraulic gradient necessary for such a liquid flow-path length, For larger diameter columns, two opposite side downcomers or a center downcomer normally is used unless the total amount of liquid collected is relatively small. 

A liquid collector plate must be of gasketed construction so that it can be sealed to the sup-... 

A modified active method was used for collect gaseous metals from soil air (Wang et al. 2008). The sampling device consists of a cone-shaped sampler, a special Millipore filter (0.45 jam), a liquid collector, and a battery-operated pump. The liquid collector comprises a high... 

Figure 7.4 shows a modern, narrow-trough, liquid collector-vapor distributor chimney tray. While the initial vapor distribution through a packed bed is not quite so critical or difficult as the liquid distribution, it is still important. 

Liquid Collector A medium-temperature solar thermal collector, employed predominantly in water... 

Liquid collectors are installed when liquid must be collected for redistribution or drawoff (e.g., for external cooling). The common device used is a chimney tray, which is similar to an orifice redistributor, but without perforations. Another common device is the Chevron-type collector, which is a series of Chevron blades, with liquid being collected at the bottom of the blades. 

Weber R. J., Orsini D., Daun Y., Eee Y. N., Klotz P. J., and Brechtel F. (2001b) A particle-into-liquid collector for rapid measurement of aerosol bulk chemical composition. Aerosol Sci. Technol. 35, 718-727. 

We conducted cold flow model experiments in a air-water/glycerin system to investigate a cause of maldistribution in a catalyst bed. The apparatus used was a 30 cm I.D. acrylic column equipped with a liquid distributor at the top and a liquid collector with 33 compartments at the bottom. Bed depth can be varied by combining the pipes. Liquid distribution at a given depth of the bed was estimated by measuring the liquid flow from each compartment of the collector. We examined effects of gas and liquid velocity, liquid viscosity, particle shapes, and ways of catalyst loading on liquid distribution in the bed. An increase in liquid velocity or viscosity slightly improved liquid distribution. However, gas flow rate did not affect liquid distribution. 

Liquid collectors provide for withdrawal of products, mixing of new feeds with the internal liquid traffic, and remixing to avoid composition gradients after a certain height of packed bed has been traversed. Liquid collectors are often designed as one item to be integral with vapor distributors and liquid redistributors. 

Under normal service conditions, the liquid collector is a separate tray from any liquid distribution device. The basic collector is a chimney tray with a sump (Fig. 9). The chimneys provide passage for vapor rising through the tray. The sump(s) provides for liquid drainage into a draw nozzle (for product draw) or... 

Weir redistributors These are identical to notched-trough distributors. Because weir redistributors cannot collect liquid from the upper section, a liquid collector such as a chimney tray or chevron collector (Chap. 4) or a collecting support plate (e.g., the upper plate in Fig. 3.8c) is usually required above the redistributor. 

Generally, redistributors for large-diameter (> 3-ft) columns are of the orifice or weir type. The orifice type is more popular because it does not require the addition of a liquid collector, which consumes vertical space and increases column cost and complexity. Other pros and cons of orifice and weir redistributors, as well as application guidelines for each type of redistributor, are identical to those described earlier for orifice and weir distributors. The general dos and don ts for distributors and for liquid inlets into distributors also extend to redistributors. Additional guidelines unique for selection, design, and operation of redistributors are presented below. 

In very large columns (>20 to 30 ft), a redistributor may not be sufficient to mix the liquid adequately. In such cases, mixing can be improved by adding a liquid collector, from which the liquid is fed to the redistributor. 

Chimney trays (Fig. 4.10a, 6) are used for withdrawing intermediate liquid streams from the column in a packed tower, they are also used as liquid collectors or vapor distributors. Alternative devices used for liquid withdrawal are downcomer trapouts in tray columns, chevron collectors, and some redistributors in packed columns. Compared to these alternative devices, chimney trays have the following advantages ... 

Chevron collectors are used in packed columns as liquid collectors for partial drawoff or for feeding to a redistributor which is not selfcollecting (e.g., a notched-trough redistributor). They are sometimes also used as total drawoffs, but are less suitable than chimney trays for this purpose. The chevron collector (Fig. 4.13) consists of evenly spaced chevron blades several inches high. Liquid collects at the bottom of the blades and runs into a draw pan. From there it can be taken out or fed to a redistributor. 

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