Bubble trays types

Available in metal only, compared more with tray type performance than other packing materials. About same HETP as Spraypak for available data. Used In towers 24 inches and larger. Shows some performance advantage over bubble cap trays up to 75 psia in fractionation service, but reduced advantages above this pressure or in vacuum service. 

Tray Thickness (Net Required for Bubble Cdps) Type of Flow Split, Cross Inlet Weirs (Y No) ... 

Figure 12.17. Glitsch truss type bubble-tray in stainless steel for a 1.9 m absorption column...

Cooled reaction gases are absorbed in water/weak acid using a sieve tray-type tower. The bottoms from this tower is a so-called red product acid, the colour resulting from dissolved nitrogen oxide impurities. The red product acid is then bleached in a smaller sieve-tray stripping column. Air is bubbled through the red acid to strip out the dissolved nitrogen oxides. Bottoms from this column is the product nitric acid at 60%(wt.) concentration. 

Bleaching Column The bleaching column is a smaller sieve tray-type column. Impure acid runs down the column from the top tray and air is bubbled up through the liquor to remove dissolved nitrogen oxides. The acid from the base of the column is the final desired 60%(wt.) product. 

Only tray-type columns were considered because of the difficulty of incorporating an effective cooling circuit into a packed column. Sieve trays (as opposed to bubble or valve-type trays) were preferred because of the ease of installing cooling coils and also their low unit cost. Details of tray selection are included in Appendix G.l. 

Specifying the need for a tray-type column, the type of tray must be determined. Sieve trays are considered most appropriate for this application. They offer a simple and inexpensive construction with low pressure drop (if the hydraulic design is adequate). Bubble cap and valve-type trays offer advantages in controlling liquid droplet entrainment, but pose significant difficulties for installation of cooling coils. 

Data specific to tray type must be established next, but these inputs will be discussed later. The data inputted for the next six prompts are the same for all tray types and are primarily for tray efficiency calculations. If tray efficiency or tray liquid residence time values are not desired, these inputs may be skipped (i.e., remain as zero values). However, for bubble cap and sieve trays, the SURF TENS DYN/CM prompt is for active area tray flood calculation. This value should therefore be inputted. 

The jet flood equation is also based on the work of Souders and Brown [12]. This equation computes the ratio of the square power of the vapor load (noted in this chapter as Vload) to a constant, 8.75, to derive the tray flood. It has been used for over three decades by tray vendors (Koch and F.W. Glitsch [3]) to design and rate sieve-type trays. In many cases, especially for sieve-type tray design, jet flood governs tray flood and thus is the primary sieve tray design and rating equation. In contrast, Eqs. (3.88) through (3.90) are the principal equations for flood determination for both valve- and bubble cap-type trays. 

Fjj is the cost factor for tray type (valve, grid, bubble cap, sieve) ... 

The discussions in this chapter emphasize sieve and valve trays, as these trays Eire most frequently encountered in industrial practice. Several of the considerations also apply to other tray types (e.g., bubble-cap trays). Considerations unique to bubble-cap trays were excluded from this chapter. The infrequent application of this type of tray in modern distillation practice argnes against a detailed discus-... 

As noted above, a number of equipment parameters must normally be specified so that the mass transfer coefficients can be estimated correctly. For example, the diameter of all columns must be known. For trayed columns, the tray type, weir height, liquid flow path length, and bubbling area must be known for packed columns, the packing type, size, and material must be known. It may also be necessary to allow for different diameters, tray or packing type, or other tray or packing parameters in different parts of the same column. 

Technological details and operating characteristics of various types of plate columns are extensively discussed in textbooks on mass transfer (e.g., see Treybal [44]). The results of extensive research on bubble tray design is reported in the American Institute Chemical Engineers Bubble Tray Manual [45]. Flooding and weeping limits and further aspects of sizing are mentioned in a review by Zenz [5]. 

The devices of contact between liquid and vapour in the distillation and absorption columns which we meet most generally are trays with sieves and with valves and, in a more or less large extent, of trays with bubble caps. The capacity of retention of these trays is mostly limited by the phenomena of entrainment or flooding. In all the distillation columns of trays type, liquid entrainment and flooding can be present. 

Type Spray Bubble Tray column Random... 

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