Page 32 - Separation process principles 2

Part 1

Fundamental

Concepts

In the first five chapters, fundamental concepts are stagnant, laminar-flow, and turbulent-flow conditions,
presented that apply to processes for the separation by analogy to conductive and convective heat transfer
of chemical mixtures. Emphasis is on industrial wherever possible.
processes, but many of the concepts apply to small- Many separation operations are designed on
scale separations as well. In Chapter 1, the role of sep- the basis of the limit of attaining thermodynamic phase
aration operations in chemical processes is illustrated. equilibrium. Chapter 4 covers mass-balance calcula-
Five general separation techniques are enumerated, tions for phase equilibrium in a single contacting stage
each being driven by energy and/or the addition of that may include vapor, liquid, and/or solid phases.
mass to alter properties important to separation. For Often the degree of separation can be greatly improved
each technique, equipment types are briefly described. by using multiple contacting stages, with each stage
Various ways of specifying separation operations are approaching equilibrium, in a cascade and/or by using
discussed, including component recovery and product a sequence of two or more different types of separation
purity, and the use of these specifications in making methods in a hybrid system. These are of great impor-
mass balances is illustrated. The selection of feasible tance to industrial separation processes and are briefly
equipment for a particular separation problem is briefly described in Chapter 5, before proceeding to subse-
covered. quent chapters in this book, each focusing on detailed
The degree to which a separation can be achieved descriptions and calculations for a particular separation
depends on differing rates of mass transfer of the indi- operation. Included in Chapter 5 is a detailed discus~
vidual components of the mixture, with limits dictated sian of degrees-of-freedom analysis, which determines
by thermodynamic phase equilibrium. Chapter 2 is a the number of allowable specifications for cascades
review of thermodynamics applicable to separation and hybrid systems. This type of analysis is used
operations, particularly those involving fluid phases. throughout this book, and is widely used in process
Chapter 3 is an extensive discussion of mass transfer simulators such as ASPEN PLUS, CHEMCAD,
of individual components in binary mixtures under andHYSYS.

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