Separations analysis fundamentals - Principles of Chemical Separations with Environmental Applications - page 33

3

Separations analysis fundamentals

A journey of a thousand miles starts with a single step.

- ANCIENT PROVERB

As with most engineering evaluations, mass and energy balances must be used as part of the
analysis of a particular separation process. Prior to an understanding of a specific separation
process, an understanding of the basis for evaluation of these processes is required. Since
separation processes involve separation of mass, the focus will be on the use of mass balances
and mass transfer for analysis. This chapter, therefore, focuses both on mass balances,
specifically as applied to separations, and on the fundamental concepts of mass transfer
that are essential to comprehension of equilibrium- and rate-based processes.

3.1 Objectives

1 Write a mass balance in words.
2 Define a macroscopic and microscopic balance.
3 Define an overall and component mass balance.
4 State the basis for equilibrium- and rate-based process analysis.
5 Apply mass balances to analysis of equilibrium- and rate-based processes.
6 For equilateral and right triangle three-component equilibrium diagrams, identify:
(a) the two-phase region;
(b) tie-lines.
7 Be able to apply the lever-arm rule to find:
(a) the mixing point ( M ) on a counter-current cascade;
(b) the flowrates of streams (instead of using a mass balance).
8 Write the equations that describe the Langmuir and Freundlich isotherms and be able
to determine the constants from batch-type adsorption test results.