Environmental concerns have raised public awareness of environmental issues
and are driving forces for regulation; The impact of regulation on the cos
t of production is expected to become important in determining the internat
ional competitiveness of the US chemical industry. In response to cost pres
sures, industry has launched a number of initiatives aimed at improving eff
iciency and reducing environmental impact. Some of these environmental succ
ess stories are receiving increased national attention due to programs such
as the Presidential Green Chemistry Challenge Awards Program. In addition
to traditional metrics for evaluating process performance, such as producti
vity, environmental considerations increasingly are important in process de
velopment.
Chemical processes evolve through life cycle phases, beginning with researc
h, and then moving to process engineering, plant operation, and eventually,
decommissioning. The number of technology options available for reducing e
nvironmental impact are highest early on in the life cycle and then decreas
e drastically. In contrast, costs associated with resolving an environmenta
l problem typically increase exponentially as the process matures and the s
cale of equipment gets larger. There is, therefore, a considerable incentiv
e to address and resolve environmental issues early in the life cycle.
Chemical reactions responsible for producing high value-;added products are
, in most cases, also responsible for generating by-products and pollutants
. New chemical and biochemical approaches are providing new reaction concep
ts. As in the development of traditional chemical and petrochemical process
es, reaction engineering, broadly defined as the field that quantifies the
engineering aspects of chemically reactive systems, is providing enabling t
ools that accelerate the development of environmentally friendly processes.
Core reaction engineering methods are being utilized for kinetic modeling,
reactor selection, scale-up, and design. Meanwhile, the research frontiers
are providing new reaction engineering tools,from computational chemistry
to probe the nature of catalytic active sites to computational fluid dynami
cs modeling for designing the internals of reaction-separation systems.
The long-term goal is to develop processes having 100% raw materials utiliz
ation, or zero waste. The near-term strategy for controlling emissions is t
o institute pollution prevention programs and install cost-effective end-of
-pipe technologies. These technologies typically control generic classes of
air pollutant emissions such as carbon monoxide, volatile organic compound
s (VOCs), nitrogen oxides (NOx) and sulfur oxides (SOx). Technologies for t
reating wastewater are also available. Over time, a shift in focus is expec
ted, from mere compliance to a point where environmentalism, like safety, i
s fully integrated into the corporate culture. The present paper discusses
the role of reaction engineering in the development of environmentally-frie
ndly processes. Select examples of processes, from the author's experience,
that benefit from reaction engineering will be presented. (C) 1999 Elsevie
r Science Ltd. All rights reserved.