Page 26 - Sustainability in the Process Industry Integration and Optimization

I n t r o d u c t i o n a n d De f i n i t i o n o f t h e F i e l d 3

into any product’s life-cycle assessment (LCA); see, for example,
Masruroh, Li, and Klemeš (2006).

1.2 Energy Efficiency
The task of saving energy—especially at a time of rising energy
costs, demand, and carbon emissions—must be taken seriously by
all communities and industries. Society is driven by the economics
of individual situations, and no section of society worldwide can
be expected to save energy at any cost. Thus, energy-saving
measures must be considered within the context of such issues
as environmental factors, legislatively imposed constraints, and
pressure from conscientious consumers. The simplest and most
obvious technique involves energy auditing and applying good
housekeeping measures. In many cases even these simple measures
are not fully understood or completed in sufficient detail. To
undertake a worthwhile energy audit, correct measurements are
necessary. Also, because in many cases energy demand is not
constant and instead fluctuates considerably, the monitoring of
energy consumption has to be performed over specific (or extended)
periods of time. Recommended monitoring techniques are described
by various sources: utility companies, such as SEMPRA ENERGY
(2009); governmental agencies, such as the U.S. Department of
Housing and Urban Development (2009); and international groups,
such as the International Energy Agency (Mandil, 2005).
Improvements in energy efficiency must often be achieved by
more complex means, such as those associated with improved
design and operation. It is of paramount importance that all
energy-related processes operate with maximum efficiency and
minimum energy input. These systems should also ensure that
they are fueled as much as possible by low-value inputs or recycled
wastes, such as process outputs—for example, “off-gases” and hot-
water waste (AEA Technology, 2000). To ensure that systems are
designed to be as efficient as best practice allows, optimization
methods are frequently employed for grassroots design, retrofit,
control, and intelligent support systems for processes, plants, and
buildings. One technology that has a strong reputation for
improving energy efficiency through better design is Pinch
Technology (Linnhoff and Vredeveld, 1984), which has been in use
for more than 20 years. This technology, through feedback from
practical applications and industry professionals, has been
continuously developed and expanded (Klemeš et al., 1997; Smith,
2005; Klemeš, Smith, and Kim, 2008). Details on the successful
applications of Pinch Technology in various industrial sectors are
described in Chapter 11.
The sustainability of energy systems can also be considerably
improved by making use of renewable energy sources (e.g., biofuels,