Sieve-plate design

The fraction of plate area occupied by disengaging and distributing zones ranges from 5 to 20 percent of the cross section. For most sieve-plate designs, these zones are eliminated completely. 

Solvent recovery column plate column, diameter 0.6 m, height 6 m, 10 stainless steel sieve plates, design pressure 2 bar, column material carbon steel. 

This method, in conjunction with standard design recommendations, is both simple and effective in determining the final sieve-plate design. Details of the necessary calculations are presented in Appendix G.3. 

The sieve-plate design is limited by the need for cooling coils. The tray design must ensure that the cooling coils sit easily in the layer of liquid. Therefore, the minimum weir height available was 40 mm. Despite this initial constraint a satisfactory tray design was developed. 

G.3.2 Sieve-Plate Design above the Weak-Acid... 

Sieve trays are used throughout the absorption column, however two distinct hydraulic designs are required. The first sieve plate design is required for trays below the weak-acid feed point. Above the weak-acid feed point, the downcoming liquid flowrate is diminished. The vapour flowrate essentially remains constant throughout the column. Different vapour to liquid ratios above and below the weak-add feed point require a second hydraulic design to be considered. 

G.3.1 Sieve-Plate Design at and below the Weak-Acid Feed Point... 

Liquid-phase back mixing is a serious issue for reactions that have nonzero-order kinetics with respect to the liquid-phase reactant. Sectionalization of bubble column using sieve plates of relatively low free area is an attractive choice in such a case. Although this choice has been mentioned in the literature, its application in solid-catalyzed reactions has not attracted any attention. The sieve plate design must be such that it prevents weeping (Prince 1960). The free area in such sieve plates is... 

Taking all experiments into account, if particles collapse, a churn turbulent flow region already appears at lower gas throughputs. In sieve plate design, this aspect has to be checked additionally. For the determination of the size of the emerging bubbles, well--known methods like that of Ruff (l4) can be used. 

---