Model-Free Adaptive Control
of Tomato Hot Breaks
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| • Handles wild tomato flow and other process
upsets. |
• Temperature control is improved by at
least a 50% reduction in temperature variability. |
| • Prevents tomato paste overheating. |
• Steam consumption is reduced. |
| • Reduces clogs in
the vessel due to improved temperature consistency. |
• Less cleaning and maintenance are required. |
| • Reduces variation in temperature and product
density. |
• Product quality and production efficiency
is improved. |
| • Improves efficiency & productivity. |
• Full Return-On-Investment is achieved
in less than one season. |
MFA controllers in CyboCon software quickly
and tightly controls temperature (green) by
manipulating steam (red) to compensatefor wild
tomato inflow without using feedforward control.
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Case History:
MFA at Del Monte Foods, Woodland, CA, reported in Food
Engineering Magazine
From July through early October, the
plant operates 24 hours per day as a continuous caravan
of gondola trucks unloads tomatoes into flumes feeding
the hot-break lines. Continuous throughput is critical
to cost efficiency during the short processing season
and the major problem is maintaining optimum temperature
in the hot-break process. Product flow is irregular
between truckloads, causing temperature variations in
the rotarycoil hot-break systems. Hot-break process
variables include tomato flow, steam pressure, condensate
pressure and temperature of the incoming product but
the biggest variable is flow rate which can change from
zero to 50 tons per hour in minutes.
The PID loop controlling the steam valve which regulated
hotbreak temperature was incapable of optimally adjusting
temperature to compensate for the intermittent flow
rate. The plant installed a CyboCon
model-free adaptive (MFA) control software
with nine MFA controllers to control temperature of
the hotbreak lines. CyboCon integrates with a FIX SCADA
software communicating with Allen-Bradley PLC's.
CyboCon was installed in just a few hours. The PID loops
were retained offering the operator a choice of control,
"but since installation the operators have used
CyboCon 100 percent of the time," said Operations
Manager, Rick Fenaroli. Product temperature now typically
varies within less than +/-2 °F. At the end of the
processing season there had been no failures in any
of the nine CyboCon loops and managers were evaluating
further applications with multiple inputs and a single
output such as in boiler control, and reducing solids
variability in evaporator control.
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