The liquid radial spreading coefficient of packings for absorption and rectification columns is necessary to determine the packing height which ensures uniform liquid distribution over the column cross section. The existing calculation methods can be used theoretically only when this coefficient is independent of the liquid superficial velocity, which is often not the case. A tracer method free from this limitation is developed and tested. The spreading coefficients for different sizes of modern, highly effective packings (Raschig Super-Ring, Ralu-Flow, and impulse metal tower packing) are determined. Practically, in the range of the experimental error, the spreading coefficients of these packings are independent of the liquid superficial velocity. For such packings the tracer method is expected to give the same results as the existing single jet method. Some differences between the results of these two methods are discussed and an explanation is proposed.
The operation efficiency of distillation columns with structured packing is maximal if the distribution of countercurrent vapor and liquid film flows over the column cross-section on the mass transfer surface is most uniform. Various types of structured packing are widely used in distillation columns. Formation of the temperature field maldistribution in the column cross-section is observed in large-scale distillation columns. The sizes of large-scale maldistributions on zones are commensurate with the column diameter. The aim of this work is to obtain experimental data on the separation efficiency in large-scale distillation columns and dynamics of formation of large-scale maldistributions of local parameters of vapor and liquid in a countercurrent flow over a structured packing during mixture separation. Separation of the R114/R21 freon mixture was carried out on a structured Mellapack 350.Y packing with a diameter of 0.9 m and height of 2100 mm. The experiments were carried out under conditions of complete reflux in the range of reduced vapor velocity of 0.017 < K
v < 0.035 m/s. Experimental data were obtained on the efficiency of mixture separation, pressure drop over the structured packing and parameters determining the formation dynamics of the large-scale temperature field maldistribution in the column cross-section. The presented experimental data will be used for the construction and verification of a new model of mass transfer and efficiency of mixture separation in large-scale distillation packed columns.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.