Page 20 - Design of Simple and Robust Process Plants

1.1 A New Evolutionary Step 3
The above-mentioned technical developments may form the basis for improved
plant design and operation, but much work still needs to be done. To illustrate this,
the installation of a domestic refrigerator ± an example of a simple and robust design ±
is compared with an industrial refrigerator with an installed spare unit. A compara-
tive list of devices contained in both units is shown in Table 1.1.
This example shows that a reliable unit can be built, but it also shows that there is
a vast difference in the design of a domestic unit and that of an industrial unit (Fig-
ures 1.1 and 1.2). It is also obvious that domestic refrigeration units went in the
direction of robust design, due to customer requirements. Next to the reliability of
the unit, customers also require competitive investment, low operational cost and
simple operation with no maintenance. Thus, the domestic refrigerator as a simple
and robust design is an ultimate example of:
An optimal designed safe and reliable unit, operated hands-off.

The meaning of simple and robust designs will be discussed in Chapter 2.Asan
example, it will be explained why a piping manifold ± which in essence is a simple
piece of equipment ± can be complex to operate (often, we have many line-up possi-
bilities, where operators have much freedom), although such a system is not error-
tolerant. This can be compared with a television set, which although being a compli-
cated piece of equipment is so simple to operate that it can be used easily by people
from 4 till over 80 years of age.
The above example shows the way to go. However, in industry there are also many
examples that point in the direction of simple and robust designs. Currently, in The
Netherlands, there are numerous applications of co-generation energy systems that are

Fig. 1.1. Domestic refrigerator.