Page 193 - Design of Simple and Robust Process Plants

178 Chapter 5 Process Simplification and Intensification Techniques

Atmospheric
vent
De-aerator
Steam
Boiler

Make-up
Drainage
Water Consumers
Chemical
dosing Condensate

Steam and condensate
Atmospheric
usage/losses
condensate
flash drum
Fig. 5.28. Conventional feed system for steam boiler with consi-
derable make-up to compensate for vent/usage/losses/drain,
and energy losses from the atmospheric flash steam.

L.P steam consumer
Steam
Boiler

Make-up Mim. Drainage
Water Chemical Consumers
dosing Condensate

Low pressure
condensate
flash drum

Fig. 5.29. Feed system for steam boiler with hardly any make-
up to compensate for losses, no de-aerator and condensate
pump nor energy losses.

5.6.1.1 Operation at 100% conversion
This is carried out in order to avoid expensive recycle systems. although it is often
not an option for all reactants, and especially not for equilibrium reactions. This
last point might be exploited by shifting the equilibrium by reactive distillation or
other product removal techniques such as absorption, adsorption, or extraction.
An option for nonequilibrium reactions is to design the reactor system for com-
plete conversion of one of the reactants.