Turbogrid, tray

Sutherland [69] reports for air-water entrainment of 0.0001 to 0.1 lb liquid/lb vapor, averaging 0.01 for 15-in. tray spacing at hole velocity Fj values of 3 to 15. Fh = Vq These values are 1-10% of bubble cap plates. Simkin et al., [64] reports a comparison with the Turbogrid tray giving only 3-60% of the entrainment of bubble caps over a wide range of operation. 

These three types of trays have a common feature in that they all have separate downcomers for the passage of liquid from each tray to the one below. There is another class of tray which has no separate downcomers and yet it still employs a tray type of construction giving a hydrodynamic performance between that of a packed and a plate column. Two examples of this type of device are the Kittel plate and a Turbogrid tray(53). Design data for these trays are sparse in the literature and the manufacturer s recommendations should be sought. 

TABLE 13.16. Efficiency Data of Some Operations with Bubblecap, Ripple, and Turbogrid Trays... 

A variation of the normal sieve tray is the Turbogrid tray developed by the Shell Development Company. The Turbogrid tray uses slots instead of circular holes and operates as a counterflow plate unit with no downcomers. A typical tray consists of a flat grid of parallel slots. The slots can be stamped perforations in a flat metal sheet or the open spaces between parallel bars. 

TEMA classification, 200 tube count table, 203 Turbine pumps, 134, 139, 140, 142, 143 Turner equation, leaching, 466 Turbogrid trays, 426 Two-phase fluid flow. 111, 113-117 correlations, 115 granular beds, 118 homogeneous model, 113 Lockhart-Martinelli method, 115, 116... 

The FRI data for dualflow trays have been used to form a tentative design method (Garcia and Fair, 2002). Data for Turbogrid trays have been included in the model. A generalized chart for predicting allowable vapor velocity, similar to that for cross flow trays given in Fig. 13.32(b), is included. 

Zuiderweg and coworkers identihed a segregation effect on turbogrid trays and found that towers in the range of 3- to 4-m diameter have 80% or less of the efhciency of a small (0.5 m) tower, because of phase segregahon and channeling. 

FIGURE 12.40 Efficiency of stamped turbogrid trays, methanol/water system. One-meter column, atmospheric pressure, total reflux. (Kastanek et al., 1969. IChemE Symp. Ser. 32, 5-100.)... 

Turbogrid trays use rectangular slots instead of circular holes no liquid downcomers required have the lowest cost and best operating performance. 

Trays with drilling or slits in the base plate. Liquid flow controlled across the base plate or drops downward through the base plate openings where the vapor flows counterflow upward, e.g., sieve tray, turbogrid tray)... 

Holes are sometimes drilled in side-to-side baffle trays, and the extreme in such a trend results in perforated trays, sieve plates, Turbogrid trays, and Ripple trays. In these, both the down-flowing liquid and the rising vapor pass through the same openings. 

The various perforated or bar-type plates have hi capacities (see curve 2y Fig. 16-13) and appear to produce the same efficiencies as bubble or Kaskade plates. Of even greater importance, they are mechanically very simple compared with bubble plates. In several designs, no downcomers whatever are provided. Turbogrid trays fail to function properly if the actual load is under about 40 per cent of the design load. 

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