Performance of combined mesh packing and sieve tray in distillation

Abstract

The hydraulic and mass transfer performance of a combined knitted mesh packing and sieve tray has been measured for the distillation of methanol-water mixtures. It was found that by adding a shallow bed of packing, the Murphree tray efficiency increased by 40-50% over a wide range of concentrations and flow rates. This increase in tray efficiency can be attributed to a much smaller and more uniform bubble formation on the packed tray. Hydraulic measurements have shown that the packed trays have lower weeping and entrainment, as well as slightly higher froth heights and pressure drops.La performance hydraulique et la performance du transfen de matikre d'un garnissage B mailles perfortes et d'un plateau perfort combinks, a ktk mesurke pour la distillation de mtlanges mkthanol-eau. On a trouvt qu'en ajoutant un lit de garnissage peu profond, l'efficacitt de Murphree du plateau augmentait de 40 B 50 % pour une large gamme de concentrations et de debits. Cette augmentation de l'efficacitk du plateau peut &tre attribute B une formation de bulles plus petites et plus uniformes sur le plateau garni. Des mesures hydrauliques montrent que les fuites et I'entrainement des plateaux garnis sont plus faibles et que la hauteur de mousse et les pertes de charge sont lkgbrement plus grandes.

Effects of surface tension on tray point efficiencies

“…The distillation experiments were carried out at total reflux under ambient pressure in a 0.153 m diameter column. Schematic diagrams of the experimental apparatus and a complete description of the facilities as well as operational procedures were given previously (Chen et al, 1990). The dimensions of the column and test trays are shown in Table 1.…”

Fouling of Sieve Trays

“…Numerous studies have been made to better understand tray efficiency, pressure drop, capacity, weeping an entrainment rates. A previous study has shown that a bed of mesh packing on sieve trays can increase the tray efficiency (Chen et al, 1990). However, foulig may occur on the mesh packing, which in turn may reduce the tray lifetime.…”