Page 25 - Sustainability in the Process Industry Integration and Optimization

2 Cha p te r O n e

demands have resulted in annual increases in energy consumption.
Furthermore, many nations have accelerated their development in
the last 10 years, and countries (such as China and India) with large
populations have seen significant increases in energy demands.
This growing energy consumption has also resulted in unsteady
climatic and environmental conditions in many areas because of
increased emissions of CO , NO , SO , dust, black carbon, and
2 x x
combustion process waste (Klemeš et al., 2005a; Klemeš, Bulatov,
and Cockeril, 2007). It has become increasingly important to ensure
that the production and processing industries take advantage of
recent developments in energy efficiency and in the use of
nontraditional energy sources (Houdková et al., 2008; Lam,
Varbanov, and Klemeš, 2010). The additional cost is related to the
amount of emitted CO and often takes the form of a centrally
2
imposed tax. A workable solution to this problem would be to
reduce emissions and effluents by optimizing energy consumption,
increasing the efficiency of materials processing, and also increasing
the efficiency of energy conversion and consumption (Klemeš et al.,
2005b).
Although major industry requires large supplies of energy to
meet production, it is not the only sector of the world economy that is
increasing its demands for energy. The particular characteristics of
the other sectors (e.g., transport, residential) make optimizing for
energy efficiency and cost reduction more difficult than in traditional
processing industries, such as oil refining, where continuous mass
production concentrated in a few locations offers an obvious potential
for large energy savings (Al-Riyami, Klemeš, and Perry, 2001). In
contrast, for example, agricultural production and food processing
are distributed over large areas, and these activities are not continuous
but rather structured in seasonal campaigns. Hence, energy demands
in this sector are related to specific and limited time periods, so the
design of efficient energy systems to meet this demand is more
problematic than in traditional, steady-state industries.
This chapter proceeds by first outlining the field of energy
efficiency, including its scope, actors, and main features. The next
step is to describe energy-saving techniques generally and then to
specify an integrated approach: Heat Integration. An increasingly
prominent issue is assessing and minimizing emissions and the
carbon footprint. The carbon footprint (CFP) is defined by the U.K.
Parliamentary Office for Science and Technology as the total amount
of CO and the other greenhouse gases emitted over the full life cycle
2
of a process or product (POST, 2006). There have been numerous
studies (see, e.g., Albrecht, 2007; Fiaschi and Carta, 2007) that
emphasize the “carbon neutrality” of renewable sources of energy.
However, even renewable energy sources make some contribution to
the overall carbon footprint, and assessment studies frequently do
not account for this. The carbon footprint should also be incorporated