Lecture 1-Introduction - Separation Process Engineering...

Separation Process Engineering
CHEN 312
• Instructor: Yousef Salameh, PhD,
Chemical Engineering, FS1 402, ext 3602,
email: [email protected]
• Textbook:
Wankat, Phillip C. Separation Process
Engineering, Third Edition , Pearson
Education, Inc., New Jersey, 2011.
ISBN: 0-13-279021-1

Introduction
• Separations are crucial in chemical engineering. A typical
chemical plant is a chemical reactor surrounded by separators,
where raw materials are prepurified in separation devices and fed
to the reactor; unreacted feed is separated from the reaction
products and recycled back to the reactor.
• Chemical plants commonly have from 40% to 70% of both capital
and operating costs in separations.
• Separation processes can involve two phases (gas and liquid,
liquid and solid, gas and solid or two immiscible liquids)
• Relatively easy to separate two phases due to density difference.
• Difficult to separate components from a single phase.

• Aim of most processes designed to separate a mixture of
components is to get the components into different phases
and then to separate the phases.
Functions of separation processes
• Purification: undesired components in the feed mixture are
removed from the desired species.
• Concentration: higher concentration of the desired
components, which are initially dilute, are obtained.
• Fractionation: two or more components are segregated into
product streams of different composition.

 For a separation to occur there must be a difference in either a
chemical or physical property between the various components of
the feed stream. This difference is the driving force basis for the
separation.
Differences are either:
– Equilibrium based
– Rate based
 If two phases are at equilibrium, the temperatures, pressures and
fractions of them cease to change. Although molecules keep
moving from one phase to another, but in the same rate.

 The equilibrium stage concept is applicable when the process
can be constructed as a series of discrete stages in which the two
phases are contacted and then separated. The two separated
phases are assumed to be in equilibrium with each other.
 This simplifies the design and analysis of chemical engineering
separations and unifies the basic design principles and methods for
a given separation method (unit operation).
Unit Operations is a method of analysis and design of chemical
engineering processes in terms of individual tasks/operations.
- It is a way of organizing chemical engineering knowledge into
groups of individual tasks/operations.

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