1. A R O U N D T H E L O O P
CLIFFTENT For Process Optimization
66 D E C E M B E R / 2 0 0 4 w w w. c o n t r o l g l o b a l . c o m
y first assignment as a newly hired control systems repre-
sentative at IBM in 1961 was to evaluate the work being
done at DuPont’s Repauno Works in southern New
Jersey. Being an IBM test site I was sent to see if the results of
our work there could help us sell our recently announced IBM
1710 Industrial Computer Control System. The process being
studied was a fixed-bed reactor for acrylonitrile synthesis. A prin-
cipal control problem arose from the catalyst activity which
degraded so steeply that parallel reactors were needed, one in
synthesis mode while the other was being
regenerated. Deciding when to switch so
as to maximize productivity was an impor-
tant objective.
A really talented team from IBM
Research (Jack Bertram, Dick Stillman, Dick Koepke plus
others) had modeled the synthesis process in a set of cou-
pled, partial differential equations. Solving these equations
numerically, however, required several minutes on an IBM
7090 to simulate a few seconds of real-time. All went back to
the drawing board and the team reduced the theoretical
model to a set of easily solvable empirical relationships cov-
ering the operating space of interest. Meanwhile, back at
DuPont, researchers were also hard at work trying to identify
an improved catalyst that didn’t degrade significantly.
“Thank you very much,” said Dupont, “it was a great proj-
ect. We learned a lot about our process and how to control
it. On further review we really don’t need the computer con-
trol system as we had initially thought.”
I learned right from the start that process optimization was
a really tough way to sell control systems. We had recently dis-
covered that paper-making was a very complex process that
control computers could facilitate by making key perform-
ance indicators available to the machine tender in real-time.
Without recourse to higher mathematics, the control system
could significantly improve overall machine productivity dur-
ing paper-grade changes, upset recovery (e.g., sheet-break)
and other transient conditions. Process optimization became
a future intangible that could close the deal if necessary.
During ISA/2004 in Houston, I had a long discussion over
lunch with Pierre R. Latour, a recognized authority in
process automation technology and successful entrepreneur
in several process control ventures. Latour began his career
in the early 1960s with DuPont and Shell Oil after receiving
a PhD in Chemical Engineering at Purdue. He worked on
the first Shell computer control project (FCC–Deer Park
Refinery 1966). A two-year tour as a captain in the U.S. Army
followed at NASA’s Manned Space Flight Center managing
the Apollo Docking Simulator development. After mustering
out, Latour co-founded Biles & Associates (later acquired by
Invensys) and Setpoint (later acquired by Aspen Technology).
Latour served in a business development capacity as Vice
President at Aspen prior to launching his current consul-
tancy–CLIFFTENT, Inc. (clifftent@hotmail.com).
Latour is nothing if not passionate about the value of the
CLIFFTENT methodology (http://groups.msn.com/CLIFF-
TENT ). His rapid-fire discourse barely allows for dialog and
I’m certain that I have only a superficial understanding of this
method of selecting the optimal set-points for maximum eco-
nomic yield from a process or operation.
His quarrel with process control as currently practiced
boils down to two points:
1. No consistent, objective method exists for assessing the
economic value of improved dynamic performance.
2. No incentive exists for control systems implementers to
deliver sustained performance improvements.
Latour’s answer to the first is CLIFFTENT–a mathemati-
cal method for optimizing setpoints and measuring the
financial value of reduced variance for any controlled vari-
able or key performance indicator. His answer to the second
is SR2 (Shared-Risk, Shared-Reward)–a method for licens-
ing technology solutions based on their performance as
measured by CLIFFTENT.
This is a guy you ignore at your peril. He has demon-
strated a deep technical knowledge of chemical process con-
trol, as well as the ability to survive and prosper as a business
leader. If I were a chemical process manager, a control sys-
tems technologist or a business entrepreneur in a related dis-
cipline, I’d listen to Pierre Latour quite closely.
Terrence K. McMahon
McMahon Technology Associates
Mcmahontec135@aol.com
C
MM
“CLIFFTENT–a mathematical method for optimizing setpoints
and measuring the financial value of reduced variance for any
controlled variable or key performance indicator.”
Atl
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