Use of structured packing as a dualflow tray in distillation.

摘要

Dualflow trays, or trays without downcomers, are a type of vapour-liquid contacting device used in mass transfer applications. This type of tray is known for having a higher capacity and lower pressure drop than conventional cross-flow trays.; In this study, a novel dualflow tray design is proposed. This new tray type makes use of a thin slice of structured packing and, as such, is named the structured packing tray (SP-tray). This tray type is compared to the commercially available and widely known dualflow sieve tray using hydraulic and mass transfer characteristics.; The SP-tray was found to have a higher capacity compared to the dualflow sieve tray. However, the stability of the SP-tray is strongly dependent on the liquid density of the system and liquid loading. While the SP-tray out-performs the dualflow sieve tray in high liquid density systems (rhoL = 1000 kg/m3) and operation at high L/V ratios, it appears to be susceptible to spraying in low liquid density systems (rhoL = 788 kg/m3) and, as such, its capacity is decreased. It was found that the efficiency of the SP-tray remains fairly constant over a wide range of vapour loadings which demonstrates a high turndown ratio; whereas for the dualflow sieve tray, the efficiency is strongly dependent on the vapour loading.; Overall, it is the author's belief that the SP-tray is a superior tray when operated under the right conditions. Operation in distillation conditions using high liquid density systems and high liquid loadings as found in absorption columns are thought to be the optimal conditions for operation of the SP-tray. Based on the work presented in this thesis, further studies into the operation of the SP-tray are warranted.