130 ◾  Index
Heavy key impurity, 17
concentration of and quality
measurements, 58
stripping factor values for, 50–53
Hydraulics, 45–46
I
Impurities, 58. See also Heavy
key impurity; Light key
impurity
Individual component material
balance, 24
Inlet streams, 8–9
Integral action
calculation of for feedback
control loop, 76
effect of, 93–99
Integral time constant, 76, 82
relationship with response time,
94
Integrating control loops, pattern
recognition tuning of,
99–102
Integrating process response, 80,
114–116
Integrators, process concept for
modeling of, 114
Internal model control (IMC),
tuning rules, 113–114
Inverse lever–arm rule, 25
K
Key impurity concentrations. See
also Heavy key impurity;
Light key impurity
expert system rules and
optimization of, 65–66
quality measurements and, 58
specification limits and, 19
temperature changes and,
27–29
Key impurity separation power,
17–18
energy consumption required to
double, 20
L
Level controllers, 115
tuning of, 99–102
Lever, 25
Light key impurity, 17
concentration of and quality
measurements, 58
stripping factor values for, 47–49
Lights, weight fraction of, 24–25
Liquid phase mass transfer unit,
48–49
Load change, 94–96
control loop response to, 95
level response to, 101
Low-level constraint control, use of
in reflux control scheme,
37–38
M
Manipulated distillate control
scheme, 34–37
Manual control
manipulated distillate control
scheme, 35
reflux control scheme, 38
Mass transfer
rectification constraint, 50–53
stripping constraint, 47–50
Material balance control schemes,
34
Material balance split, 10, 20, 23
equations for, 24
side draw flow rate control and,
41
temperature change and shift in,
27–29