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Commissioning and Qualification 345
occurred throughout the functional testing, reagent times were simply tweaked. At
one point late in the functional testing, make-up failures started to occur in some
circuits. With little or no accumulated data, the problems were difficult
to troubleshoot.
Arequest was made for help to troubleshoot the problem. Historian data was
first accumulated in aspreadsheet for all previous functional testing (and reagent
pump testing) runs for both alkaline and acid. Average fill volumes were calculated
for circuits based on the alkaline concentrations achieved and the alkaline addition
times. Calculations were then done to determine what the acid reagent addition
times should be. Inconsistencies were found. It was possible to correlate and
attribute the inconsistencies to adjustments made in the acid pumps. It was also
possible to determine the acid conductivity probe for one of the CIP skids
was failing.
Fix Hardware Mistakes
It is very tempting during functional testing to compensate for hardware deficiencies
by developing software workarounds. Trying to outsmart the hardware can
even be very satisfying. This may not cause great difficulties for very simple
systems. However, for complex systems, especially where multiple workarounds
are performed, these patches make the software far more complex and may
ultimately prevent you from having the system operate the way you want.
Early in Project A, aproblem was discovered with the type of flowmeter used
on the CIP skid. If the flow was ever blocked while the pump was running, the
flowmeter did not read “zero.” Instead it actually spiked up to avalue close to its
upper calibrated range value. The flowmeter could have been replaced with amore
suitable flowmeter; however, workarounds were implemented instead. These
workarounds got very complex during Project A. It has not been quite as
complicated for Project B, but the following problems remain:
1. Sequences have to be designed without ever blocking flow, otherwise total
volumes will be way off.
2. The control valve output was limited to a15% minimum to avoid problems
with the flow control loop.
3. Low flow alarms are not useful for detecting closed manual valves or other
setup problem.
CONCLUSION
Complex CIP systems can be the most challenging commissioning task in you
project. Planning the commissioning can be made easier by understanding the
design and design basis, identifying all necessary activities and planning them in
the appropriate order. Using sound scientific principles in your execution will pay
great dividends in reduced commissioning time and robustness of CIP operations.