They are in association with
coolers, C-1 and C-2, in the process flow sheet. The stream
labeled H3 corresponds to the condenser in the distillation
column. Also, C1 and C2 represent the individual cold streams
that receive heat from the heaters with the labels H-1 and H-2
in the process flow sheet. The cold stream named as C3 refers
to the bottom flow that is pumped into the reboiler of the
column. The heat exchange network design is based on the
objective function of minimizing utility and capital costs. The
minimum temperature interval (DTm) for this process has
been fixed at 10 C.