Hidrodinâmica de diversos tipos de pratos: um estudo comparativo.

Abstract

With the objective of optimizing, in economic and functional terms, the contact between phases in the separation towers, several types of dishes were proposed over the years or bubbling trays. The first and most expensive of the proposed dishes is (BUBBLE - cap Tray), which has the highest efficiency among the others. Then, the perforated plate (Sieve - Tray) appeared, which, despite being the most feasible in terms of economy and design, presents serious disadvantages in its use, such as the phenomenon of drip for the anterior dish and increase of its perforations through corrosion. These phenomena contribute, in addition to others, to a process efficiency. In order to overcome the functional disadvantages of the perforated plates and to reduce the design expenses presented by the bell plates, Valve Tray was launched. It is a modern version of the perforated plates, where the holes are covered by design hoods (valves) which have a variable passage for the gas phase. Recently, the German and Japanese industries have used hybrid plates of perforated plates and valves, that is the mixed plates (Seive - Valve Tray) and have a lower efficiency than the perforated ones, but they allow to work in a wide range of operations and stable. The objective of this research is to study and parallel the hydrodynamics of the last three plates, emphasizing the influence of the liquid layer of the liquid flow, the gas and the weight of the valves and the number of holes on the plate, the gradients pressure through dry and irrigated dishes. Among the numerous configurations studied for the Mixed plates, it was concluded that the mixed models with three holes and with five holes present a better performance in terms of hydrodynamic behavior.