Sieve-Plate Hydraulic Design

The sieve plates are designed in accordance with the recommendations made in Refs. A3 to A6. The iterative design approach was suggested in Ref. A3 (p.458). The procedure is summarized below. 

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. 

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NORMAL OPERATION OF SIEVE PLATE. A sieve plate is designed to bring a rising stream of vapor into intimate contact with a descending stream of liquid. The liquid flows across the plate and passes over a weir to a downcomer leading to the plate below. The flow pattern on each plate is therefore crossflow rather than countercurrent flow, but the column as a whole is still considered to have countercurrent flow of liquid and vapor. The fact that there is crossflow of liquid on the plate is important in analyzing the hydraulic behavior of the column and in predicting the plate efficiency. 

After selection of the column internal diameter (the fundamental column specification), the sieve plates must then be designed. This involves a trial and error approach. A preliminary plate design is proposed based upon typical tray configurations, then the hydraulic... 

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. 

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