The sieve tray without downcomeris extensively used in industrial chemical processes such as distillation and absorption because it is the simplest and cheapest type of gas-liquid contacting device.Further, the importance of saving energy has recently increased the need for high-capacity gas-liquid contacting devices.In the present study, following the previous work,8j9) experiments were carried out with trays having large free areas for the purpose of clarifying the behavior and characteristics of froth. Pressure drop, liquid holdup and stable operating range were studied.

A bstractExperiments were conducted to investigate pressure drop, liquid holdup and the stable operating range of a low height packed column with regularly packed metal Raschig rings having very a large fractional void space. These factors are important parameters when designing gas-liquid countercurrent flow low height packed columns. Regularl y packed beds considerably reduce the pressure drop compared to that of random packed beds and/or plate columns. The total pressure drop appears to be smaller than the total liquid holdup. Therefore, Major factors causing pressure drop are the contraction and expansion of gas and the friction loss between gas and liquid. A macroscopic model based on the estimation of the total pressure drop was formulated and compared with experimental data of the present study. The model provides a functional way of correlating the pressure drop by using information obtained in this study of the liquid holdup and the correction factor. Furthermore, the stable operating ranges were established by parameters previously investigated by the authors.