3.2.3 Downs drill
Jim Downs (1992) of Eastman Chemical Company has insightfully
pointed out the importance of looking at the chemical component balances
around the entire plant and checking to see that the control
structure handles these component balances effectively. The concepts
of overall component balances go back to our first course in chemical
engineering, where we learned how to apply mass and energy balances
to any system, microscopic or macroscopic. We did these balances for
individual unit operations, for sections of a plant, and for entire processes.
But somehow these basics are often forgotten or overlooked in the
complex and intricate project required to develop a steady-state design
for a large chemical plant and specify its control structure. Often the
design job is broken up into pieces. One person will design the reactor
and its control system and someone else will design the separation