Physical absorption material balance

The emergence of chemical engineering as a professional field of specialized knowledge was catalyzed to a major extent by the systematic classification of apparatus in terms of the Unit Operations. With further progress, the design methods evolved for particular apparatus types have proved equally applicable to other unit operations similar in physical arrangement, material and energy balances, rate behavior, and phase equilibrium. Thus there has been a very extensive development of parallel calculation methods for the separation operations conducted under countercurrent flow conditions—the fluid-fluid operations of distillation, absorption, and extraction. 

The thermodynamics of physical absorption are formulated in analogue to distillation. Important qnantities are the minimum demand of solvent (analogue minimum reflux) and the minimum demand of stripping gas (minimum reboil). Both quantities can be formulated via material balances. 

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