Effect of liquid‐phase properties on separation efficiency in a randomly packed distillation column

Abstract

The effects of the liquid properties on packing efficiency were investigated experimentally. Tests were performed in a column packed with ceramic Intalox® saddles, 7 mm in diameter. The distillation column was operated under total reflux and at atmospheric pressure (94 kPa). Surface tension positive (methanol/water, n‐heptane/toluene), surface tension negative (benzene/n‐heptane), and surface tension neutral (methanol/isopropanol and cyclohexane/n‐heptane) systems were selected to examine the wide range liquid property effects on the height of equivalent to a theoretical tray (HETP). The surface tension gradient was found to be the dominant factor affecting HETP in surface tension positive systems, but had no effect for the surface tension negative system. For the surface tension neutral system, it was found that the liquid diffusivities and viscosities had the greatest effect on HETP. The measured HETP data was also compared with tray results obtained from literature, to determine if packing and tray efficiencies are affected in a similar manner by the liquid properties. It was concluded that the surface tension gradient, liquid diffusivities, and viscosity have similar effects on the efficiency of packed and tray columns.

Local Separation Performance for Distillation Processes in Rotating Packed Beds: Transferability and Applicability

“…Although the chemical properties are in the same range, it cannot be completely excluded that slight differences of one of those have a high impact on the flow trajectories, the breakup of ligaments, and rivulets, as well as the formation of droplets. Comparable phenomena are observed in conventional packing columns as different chemical systems with similar properties or even same chemical systems at different compositions that reach different HETP (height equivalent to a theoretical plate) values under the same operating conditions. , Therefore, the variation of chemical properties due to changes in composition is also likely to influence the fluid dynamics in RPBs. For the investigated systems, the dominant variation of chemical properties occurs for the surface tension, which is rather constant along the radius for the ethanol/1-propanol system.…”

Flow Field Simulation and Measurement in Packed Beds Based on 4D‐X‐Ray Computed Tomography

“…Packed beds are widely used in the chemical and the process industry. Packed bed reactors, for example, are very versatile and used in many chemical processing applications such as absorption, distillation, stripping, separation processes, and catalytic reactions [1][2][3][4][5]. Packed beds have been also proposed for several energy storage applications such as advanced-adiabatic compressed air energy storage [6], liquid-air energy storage [7] and thermal energy storage systems [8,9].…”

Cuboid Packed-Beds as Chemical Reactors?

“…In certain specialized forms of packed-beds, such as monoliths [7,8], the particles are fused together. Packed columns are also used for chemical separation techniques such as adsorption, distillation, extraction and chromatography [9][10][11][12].…”