Page 37 - Plant design and economics for chemical engineers

20 PLANT DESIGN AND ECONOMICS FOR CHEMICAL ENGINEERS

of Physical Chemistv, Hydrocarbon Processing, Engineering News-Record, Oil and
Gas Journal, and Canadian Journal of Chemical Engineering.
A large number of textbooks covering the various aspects of chemical
engineering principles and design are available.? In addition, many handbooks
have been published giving physical properties and other basic data which are
very useful to the design engineer.
Trade bulletins are published regularly by most manufacturing concerns,
and these bulletins give much information of direct interest to the chemical
engineer preparing a design. Some of the trade-bulletin information is con-
densed in an excellent reference book on chemical engineering equipment,
products, and manufacturers. This book is known as the “Chemical Engineering
Catalog,“+ and contains a large amount of valuable descriptive material.
New information is constantly becoming available through publication in
periodicals, books, trade bulletins, government reports, university bulletins, and
many other sources. Many of the publications are devoted to shortcut methods
for estimating physical properties or making design calculations, while others
present compilations of essential data in the form of nomographs or tables.
The effective design engineer must make every attempt to keep an
up-to-date knowledge of the advances in the field. Personal experience and
contacts, attendance at meetings of technical societies and industrial exposi-
tions, and reference to the published literature are very helpful in giving the
engineer the background information necessary for a successful design.

FLOW DIAGRAMS
The chemical engineer uses flow diagrams to show the sequence of equipment
and unit operations in the overall process, to simplify visualization of the
manufacturing procedures, and to indicate the quantities of materials and
energy transfer. These diagrams may be divided into three general types: (1)
qualitative, (2) quantitative, and (3) combined-detail.
A qualitative flow diagram indicates the flow of materials, unit operations
involved, equipment necessary, and special information on operating tempera-
tures and pressures. A quantitative flow diagram shows the quantities of
materials required for the process operation. An example of a qualitative flow
diagram for the production of nitric acid is shown in Fig. 2-1. Figure 2-2
presents a quantitative flow diagram for the same process.
Preliminary flow diagrams are made during the early stages of a design
project. As the design proceeds toward completion, detailed information on
flow quantities and equipment specifications becomes available, and com-
bined-detail flow diagrams can be prepared. This type of diagram shows the

tFor example, see the Chemical Engineering Series listing at the front of this,text.,
$-Published annually by Reinhold Publishing, Stamford, (3.