Mass transfer analysis absorbers

This is a straight line with a slope of - L/V, and is plotted in Figure 12-16B. At equilibrium, y = 0, and can be found from the operating equation as shown in Figure 12-16B. When equilibrium is not attained, the system can be designed with the mass transfer analysis discussed in Chapter 16. Co-current absorbers are used commercially for irreversible absorption. 

In packed columns, it is conceptually incorrect to use the staged model even though it works if the correct height equivalent to a theoretical plate (HETP) is used. In this chapter we will develop a physically more realistic model for packed columns that is based on mass transfer between the phases. After developing the model for distillation, we will discuss mass transfer correlations that allow us to predict the required coefficients for common packings. Next, we will repeat the analysis for both dilute and concentrated absorbers and strippers and analyze cocurrent absorbers. A simple model for mass transfer on a stage will be developed for distillation, and the estimation of stage efficiency will be considered. After a mass transfer analysis of mixer-setder extractors. Section 16.8 and the appendix to Chapter 16 will develop the rate model for distillation. 

A5. Why is the mass transfer analysis for concentrated absorbers considerably more conplex than the analysis for binary distillation or for dilute absorbers ... 

Jean-Claude Charpentier, Mass-Transfer Rates in Gas-Liquid Absorbers and Reactors Dee H. Barker and C. R. Mitra, The Indian Chemical Industry-lts Development and Needs Lawrence L. Tavlarides and Michael Stamatoudis, The Analysis of Interphase Reactions and Mass Transfer in Liquid-Liquid Dispersions... 

Hydrogen-Absorbing Metals in Electrochemical Environments Analysis of Mass Transfer and Fluid Flow for 32 Electrochemical Processes... 

In some cases, evaluating a global reaction rate based on the total radiation absorbed by the reactor is not equivalent to evaluate rates based on the radiation absorbed locally, especially when mass transfer limitations occur. Thus, appropriate analysis of radiative transfer in reactors can be a valuable tool in making design decisions. 

The development of the design equation for a countercurrent packed tower absorber or stripper begins with a differential mass balance of component A in the gas phase, in a manner similar to that of Example 2.12. However, this time we do not restrict the analysis to dilute solutions or to constant molar velocity. If only component A is transferred (4 G = VA[ = 1.0), considering the fact that the gas-phase molar velocity will change along the column, and that F-type mass-transfer coefficients are required for concentrated solutions, the mass balance is... 

Hence, the liquid-phase resistance controls interphase mass transfer and, for aU practical purposes, yj yji. This is analogous to drawing horizontal tie-lines between the equilibrium and operating lines during graphical analysis of a gas absorber, where vapor-phase mole fraction is plotted on the vertical axis and liquid-phase mole fraction is on the horizontal axis. This assumption allows one to re-express interphase transport on the liquid side of the gas-liquid interface, liquid(C —Cji)aLVL, using the interfacial equilibrium relations given by (24-36) ... 

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