Bed layer

A wide variety of complex process cycles have been developed. Systems with many beds incorporating multiple sorbents, possibly in layered beds, are in use. Mathematical models constructed to analyze such cycles can be complex. With a large number of variables and nonlinear equilibria involved, it is usually not beneficial to make all... 

On a larger level, fingering is caused by layered beds with a low k (conductivity) and lenses with a high k... 

On a larger scale, a similar process can occur. Fingering of the tracer is created by layered beds with a low conductivity and lenses with a high conductivity. The tracer that ends up in a lense travels at a relatively high speed. Those tracer molecules will reach the measuring point much sooner than the tracer molecules stuck in the low conductivity beds, thus creating longitudinal dispersion. As the lenses are not all parallel to each other, they will also create a lateral dispersion of the tracer. 

For large columns over about 1.2 m diameter the usual material of construction is mild steel or sometimes stainless steel, with a height diameter ratio of around 2 1 or greater in some cases. Access is via a top or side manway, and often the vessel carries a bottom spigot for resin removal. Windows, whilst not essential, are highly desirable to view resin levels, resin separations in mixed beds and layer beds, bed movement, and resin transfers. Most applications require the vessels to be pressure vessels and therefore are fabricated and tested to strict codes of practice. 

Due to mining of succeeding face, after determining grouting layers, bed separation was continuous, and with the mining of each... 

Because of the wide range of adsorptive properties of the gas molecules in the feed, it was recognized from the early development that more than one sorbent was needed for the separation. Hence, layered beds were used from the beginning. Typically, the first layer (at the feed end) is activated carbon, which is followed by a zeolite (e.g., 5A). The reasoning for such layering becomes obvious from the equilibrium isotherms, shown in Figures 10.21 and 10.22. The most strongly adsorbed components are adsorbed in the activated carbon bed, while the other components are separated in the zeolite bed. 

Numerous studies have been undertaken on the use of layered beds consisting of different sorbents for cyclic adsorption/ion exchange (Klein and Ver-meulen, 1975 Frey, 1983 Wankat and Tondeur, 1985 Chlendi and Tondeur, 1995 Watson et al., 1996 Pigorini and LeVan, 1997). For hydrogen purification using layered activated carbon and zeolite, Chlendi and Tondeur (1995) used the... 

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