Step 8: Control individual unit operations
Establish the control loops necessary to operate each of the individual
unit operations.
Many effective control schemes have been established over the years
for individual chemical units (Shinskey, 1988), For example, a tubular
reactor usually requires control ofinlet temperature. High-temperature
endothermic reactions typically have a control system to adjust the
fuel flowrate to a furnace supplying energy to the reactor. Crystallizers
require manipulation of refrigeration load to control temperature. Oxygen
concentration in the stack gas from a furnace is controlled to prevent
excess fuel usage. Liquid solvent feed flow to an absorber is controlled
as some ratio to the gas feed, We deal with the control of various
unit operations in Chaps. 4 through 7.