Opportunities for Energy Saving from Intensified Process Technologies in the Chemical and Processing Industries - Process Intensification for Green Chemistry - page 373

Table 15.1 Typical processing equipment used in chemical and processing industries.

Process Equipment typically used (frequency)

Process heating Heat exchanger with hot liquid (78%)

Heat exchanger with steam (72%)
Direct steam injection (50%)
Heat exchanger with hot air (22%)

Mixing Stirred tank vessel (72%)

Static in-line mixer (50%)
Mechanical in-line mixer (17%)

Reactions Batch stirred tank reactor (39%)

Continuously stirred tank reactor (CSTR) (22%)
Plug flow reactor (PFR) (6%)

Drying Fluidized bed reactor (17%)

Spray dryer (17%)
Tray dryer (11%)
Tunnel dryer (11%)
Other (33%)

intensified equipment and novel processing methods. The design of novel equipment may
involve the development of multifunctional units, such as reactive distillation (RD)
columns and heat-exchanger reactors, or the development of systems based on more
revolutionary approaches, such as high-gravity-fields technology. Ultimately it is desirable
to combine intensification techniques in order to gain synergistic effects in process
efficiency. A number of such intensification strategies have been established and a few,
such as rotating strippers, rotating packed beds, RD and static mixers, have been fully
developed and implemented, with widely demonstrated resulting benefits, while others are
still in a premature phase and require more research and development [7].
The study carried out by Linnhoff March [3] estimated the potential energy savings in
the UK chemical sector due to investment in a range of PI process unit operations
(Table 15.2). According to these estimates, the UK chemical sector could have cut its
energy consumption in 2010 by more than 21.5% as a result of overall plant intensification.
We present in this section a few potential technologies for the intensification of the
various processes identified in the survey and shown in Table 15.1.

Table 15.2 Potential energy savings in the UK chemical sector due to investment in PI.
Adapted from [ref 3] # 2008, with permission from Elsevier.

Energy saving a
(PJ/annum)

% of energy consumption in the
UK chemical sector in 2010 b

Compact heat exchangers 16 8.6

Separators 6.2 3.3

Reactors 11 5.9

Overall plant intensification 40 21.5

a Savings estimated in Linnhoff March report [3].
b Based on a total of 4439 thousand tonnes of oil equivalent consumed in 2010 [1].