Fluid Dynamics of Packed Columns

Principles of the Fluid Dynamic Design of Columns for Gas/Liquid and Liquid/Liquid Systems

verfasst von: Jerzy Mackowiak

Verlag: Springer Berlin Heidelberg

Buchreihe : VDI-Buch

Enthalten in: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik"

Inhaltsverzeichnis

Über dieses Buch

The?rstGermanedition of thebook“Fluiddynamicsofpackedcolumns with modern random and structured packings for gas/liquid systems” was published in 1991. It sold out within a few years. Added to this were numerous enquiries, in particular within the industry, prompting me to publish a second, extended edition. A packed column remains the core element of any diffusional separation process. This underlines the need for basic design principles for packed columns, which enhance the design process by making it more accurate and reliable. The SBD (suspended bed of droplets) model introduced in the ?rst German edition of the book was well received by the experts and is now used by a large number of com- nies in the industry, as it offers improved reliability in the ?uid dynamic design of packed columns. For the purpose of facilitating the design process, the SBD model was in- grated into the simulation programme ChemCAD. The software programme FDPAK, which is available for Windows, has certainly contributed to the widespread use of the SBD model. The programme is very user-friendly and the calculation results are p- sented in tabular as well as graphic form, showing ?ood load, pressure drop and hold-up diagrams in the entire operating range.

Inhaltsverzeichnis

Frontmatter

Principles of the Fluid Dynamic Design of Packed Columns for Gas/Liquid Systems

Frontmatter

Chapter 1. Introduction

Abstract

In thermal process engineering, packed columns as well as tray columns are often used for heat and mass transfer processes in rectification, absorption and extraction as well as for the cooling of gases and liquids and wastewater and groundwater treatment. They are mainly used for counter-current gas/liquid flow. Figure 1-1 shows the schematic structure of a packed column with random packing elements.

Jerzy Maćkowiak

Chapter 2. Two-Phase Flow and Operating Range

Abstract

The accurate design of packed columns requires a knowledge of the hydraulic characteristics of the respective packing element throughout the entire operating range. The gas velocity at the flooding point u_V,Fl is a particularly important parameter in this context, as it is required for the calculation of the maximum loading capacity at a given specific liquid load u_L. The higher the loading capacity of the column in the case of counter-current flow of the phases, i.e. the higher the gas velocity at the flooding point u_V, the smaller the required cross-section and diameter of the column.

Jerzy Maćkowiak

Chapter 3. Pressure Drop of Dry Packed Columns

Abstract

In the counter-current two-phase flow of gas and liquid, a pressure drop occurs in the packed column. It is important to know the pressure drop in the gas phase in single- and two-phase counter-current flow through random or structured packings, in order to assess the operating mode of packed columns.

Jerzy Maćkowiak

Chapter 4. Pressure Drop of Irrigated Random and Structured Packings

Abstract

It is important to know the total pressure drop Δp of the irrigated packed bed when designing packed columns for gas/liquid systems in counter-current flow of the phases. In absorption as well as desorption processes, the total pressure drop Δp of the packing determines the blower capacity and thus the major part of the operating costs of the process. In rectification, the sum of the top pressure p_T and the total pressure drop Δp gives the bottom pressure p_W, which determines the bottom temperature t_W. The bottom temperature, in turn, determines the effective temperature difference, at a given heating medium temperature, at which the reboiler in the distillation column must be operated.

Jerzy Maćkowiak

Chapter 5. Pressure Drop of Irrigated Random and Structured Packings Based on the Law of Resistance for Two-Phase Flow

Abstract

Chapter 4 presented a model for determining the pressure drop of irrigated random and structured packings. This model is applicable, if the law of resistance, i.e. function ψ = f(Re_V), for single-phase flow through the packing, is known. There are cases, in which experimental pressure drop data is only available for irrigated packings, which means the model presented in Chap. 4 cannot be applied unrestrictedly. In the case of tube columns and packings with a flow channel angle other than α = 30° or 45°, for which no C_B values for determining the pressure drop, acc. to Eq. (4-45), are available, the calculation of the pressure drop can only be carried out with insufficient accuracy. Here, it is advisable to apply the method developed by Maćkowiak [1, 2], which is based on the law of resistance ψ_VL= f(Re_L) for gas/liquid two-phase flow.

Jerzy Maćkowiak

Chapter 6. Fluid Dynamics of Packed Columns for Gas/Liquid Systems – Summary of Results

Abstract

One the major objectives of this book was to consolidate the extensive research material available on the fluid dynamics of packed columns in counter-current two-phase flow and to extend the application range, compared to the first German edition of this book. This was possible by deriving some generally valid equations for individual packing-specific parameters, such as gas velocity at flooding point u_V,Fl, liquid hold-up h_L at operating and flooding point and pressure drop Δp₀/H of dry and Δp/H of irrigated random and structured packings.

Jerzy Maćkowiak

Principles of the Fluid Dynamic Design of Packed Columns for Liquid/Liquid Systems

Frontmatter

Chapter 7. Basic Principles of Packed Column Design for Liquid/Liquid Systems

Abstract

Extractors used in industry can be operated with or without mechanical energy agitation, by pulsation or rotation [5, 10, 16, 17, 21].

Some of the simplest designs are spray columns without internals and packed columns containing randomly filled and stacked packing elements, tube columns or columns with structured packing, see Fig. 1-2a.

Jerzy Maćkowiak

Backmatter

Titel: Fluid Dynamics of Packed Columns
verfasst von: Jerzy Mackowiak
Verlag: Springer Berlin Heidelberg
Electronic ISBN: 978-3-540-88781-2
Print ISBN: 978-3-540-88780-5
DOI: https://doi.org/10.1007/b98397