Trays layout

Figure 8-67B. For sieve tray layout arrangements typical one-, two-, and four-pass tray flow patterns with clarifying flow markings by this author. Used by permission, Glitsch, Inc., Bui. 4900-5th Ed.

Figure 8-90. Distillation tray layout form. (Use with Figure 8-91, not reproduced to scale.) Used by permission, Wyatt Metal and Boiler Worlds, Inc. (1956).

Some of the details of tray layout are given in Figure 8-67A. The working details can be set by the required performance. 

Assume a tray layout downcomer areas, non-perforat-ed area perforated area. Base downcomer requirements on bubble cap tray information of Figure 8-100. 

From Figure 8-144 or by calculation determine the plate area required for the holes on the pitch selected. Several selections may be tried to be used with the tray layout. These should be checked to agree with the assumed per cent hole area of Step 3. 

Mechanical tray layout details. Allow a total of 3H-in. on diameter for extension of tray ring-type support into the tower. This reduces available tray area. Other support details might make more area arail-able. Each must be examined. 

Sieve or perforated trays. These are much simpler in construction, with small holes in the tray. The liquid flows across the tray and down the segmental downcomer. Figure 11.52 indicates the general form of tray layout. 

For a given tray layout there are certain limits for the flows of vapour and liquid within which stable operation is obtained. The range is shown in Figure 11.54, which relates to a bubble-cap plate. The region of satisfactory operation is bounded by areas where... 

With the same concept for tray layout as in Figure 11.55, relations for Emi and Emi may be derived. Assuming that the vapour concentration does not change in a horizontal plane, a similar analysis to that above gives ... 

Fluid mechanics. Pump heads, rates, and power piping sizes column tray layout and sizing heat-exchanger tube and shell side bafliing and sizing... 

Prepare mechanical design sketches of the absorption tower suitable for submission to a draughtsman, paying particular attention to the tray layout and any associated cooling equipment. 

During the column-sizing phase, a preliminary tray layout is prepared by setting the following ... 

Tray layout. The preliminary tray and downcomer layout is prepared in the column-sizing phase and refined during the hydraulic design phase. In addition to the parameters previously set, such parameters as hole diameter or the type of valve unit are determined. 

As stated in the introduction to Chapter 6, detailed tray layout is performed in the sscondary phase of tray design. A preliminary layout, however, is needed at the primary phase, because the layout influences column size. In the present example, the preliminary layout will be based on tray layout guidelines detailed in a companion book (1). 

Others. Based on Kister s guidelines (1), the following are appropriate preliminary choices for other tray layout parameters. 

Throughout this trial, vapor and liquid loads and physical properties are taken from Table 6.10. Tray layout parameters are taken from Table 6.11. 

Summary. Following the flooding checks, the column diameter remains at 6 ft. The tray layout remains- as specified at the beginning of this section. However, the tray spacing in the top section is extended from 18 to 21 in, so that the tower has 24-in tray spacing in the bottom section and 21-in tray spacing in the top section. 

The check shows that the pressure drop is within the desired range, and no adjustment is needed to tray layout. 

The layout for this trial is the same for the second trial except for the above changes in weir heights and clearances. Also, the tray spacing in the top section changed from 13 to 21 in. Throughout this trial, vapor and liquid loads and physical properties are taken from Table 6.10. Tray layout parameters are shown in Table 6.11. Some variables that remain unchanged from the previous trial are... 

The number of valve caps that can be fitted on a tray is at best an estimate unless a detailed tray layout is prepared. However, a standard has evolved for low- and moderate-pressure operations a 3 x 2 y2 in pattern that is the tightest arrangement available, accommodating about 14caps/ft2 (150 caps/m2). The active area does not take into account liquid-distribution areas at the inlet and outlet, nor edge losses due to support rings, nor unavailable space over tray-support beams. In smaller columns, it is possible that as much as 25 percent of the active tray area may not be available for functioning valves. For this column, which operates at low pressure, select the standard 3 x 2 /2 in pitch. 

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