Ciencias 12

PROCESS DESIGN TRENDS

Process Intensification:
Transforming
Chemical Engineering
Andrzej I. Stankiewicz,
DSM Research/Delft University
of Technology
Jacob A. Moulijn,
Delft University of Technology

T

Emerging equipment, processing techniques,
and operational methods promise spectacular
improvements in process plants, markedly shrinking
their size and dramatically boosting theirefficiency.
These developments may result in the extinction
of some traditional types of equipment, if not
whole unit operations.

oday, we are witnessing important
new developments that go beyond
“traditional” chemical engineering.
Engineers at many universities and
industrial research centers are working on novel
equipment and techniques that potentially could
transform our conceptof chemical plants and
lead to compact, safe, energy-efficient, and environment-friendly sustainable processes. These
developments share a common focus on “process
intensification” — an approach that has been
around for quite some time but has truly emerged
only in the past few years as a special and interesting discipline of chemical engineering.
In this article, we take a closer look atprocess intensification. We define what it involves,
discuss its dimensions and structure, and review
recent developments in process-intensifying devices and methods.

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American Institute
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22

January 2000

What is process intensification?
One of the woodcuts in the famous 16thcentury book by Georgius Agricola (1) illustrates the process of retrieving gold from gold
ore (Figure 1). The resemblance between some
of the devices shown in the picture (for instance, the stirred vessels O and the stirrers S)
and the basic equipment of today’s chemical
process industries (CPI) is striking. Indeed,
Agricola’s drawing shows that process intensi-

Chemical EngineeringProgress

fication, no matter how we define it, does not
seem to have had much impact in the field of
stirring technology over the last four centuries,
or perhaps even longer. But, what actually is
process intensification?
In 1995, while opening the 1st International
Conference on Process Intensification in the
Chemical Industry, Ramshaw, one of the pioneers in the field, defined processintensification as a strategy for making dramatic reductions in the size of a chemical plant so as to
reach a given production objective (2). These
reductions can come from shrinking the size of
individual pieces of equipment and also from
cutting the number of unit operations or apparatuses involved. In any case, the degree of reduction must be significant; how significant
remains a matter ofdiscussion. Ramshaw
speaks about volume reduction on the order of
100 or more, which is quite a challenging
number. In our view, a decrease by a factor of
two already bears all attributes of a drastic
step change and, therefore, should be considered as process intensification.
On the other hand, Ramshaw’s definition is
quite narrow, describing process intensification exclusively in terms of thereduction in
plant or equipment size. In fact, this is merely
one of several possible desired effects. Clearly, a dramatic increase in the production ca-

s

Figure 1. 16th century technology for retrieving gold from ore (1).

pacity within a given equipment
volume, a step decrease in energy
consumption per ton of product, or
even a marked cut in wastes or
byproducts formation alsoqualify as
process intensification.
Not surprisingly, process intensification, being driven by the need for
breakthrough changes in operations,
focuses mainly on novel methods and
equipment. But, it also encompasses

certain established technologies and
hardware. Usually, these have been
applied on a limited scale (at least in
comparison with their potential) and
have not yet generally...