Index ◾  131
Maximum process response rate
(MPRR), calculation of,
109
Maximum reflux ratio. See Total
reflux
McCabe–Thiele diagram, 19
Minimum integral of absolute error
(IAE), 88
Minimum reflux ratio, 10
energy consumption and, 18
Most responsive temperature
(MRT), 28, 29, 30
expert system rules and
optimization of, 65–66
optimization of between
distillate and bottoms
quality, 60–62
N
Normal distribution, DNS vs.
frequency of failure rate
for, 59–60
Normal Gaussian error distribution,
59
O
Offset, 75
Open-loop process gain
calculation of, 109
two-point characterization of
FOPDT response, 110–112
Open-loop process response, 106
Ziegler–Nichols rules of thumb
for, 107–110
Open-loop step tests, 114–116
Optimization, 65–69
Optimum gain, control loop
response with, 90–93
Oscillating control loops,
troubleshooting, 84–85
Outlet streams, 9
Overshoot, 85
Overshoot/undershoot ratio, 88, 98
P
Packing efficiency, vapor traffic
and, 46
Parallel algorithm for PID
controllers, 77
Pattern recognition tuning
integrating control loops,
99–102
self-regulating control loops,
86–90
PID controllers. See also Control
loops; Feedback control
loop
algorithms for, 77
Pinch condition, 46
Preact action, calculation of for
feedback control loop, 77
Pressure, control of, 9–10
Pressure drop, 45–46
Process variables
controlled, 9–10
feedback control loops and, 74
process dynamics of, 80
response time for, 99
vapor traffic, 45–46
Process water, heating with steam
injection, 74
Proportional action, calculation of
for feedback control loops,
75–76
Proportional gain, 75
effect of, 90–93
Q
Quality
DNS measurements and, 59
excessive use of steam and,
62–63