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Project Planning for CIPable Facility 25
cycle consists of aprerinse, an alkaline wash, apost-rinse, and acid wash (or rinse),
another post-rinse, and afinal rinse to minimum required resistivity of the water
going to waste at the end of the circuit. The circuit will normally be evacuated and
refilled at least four times, following the alkaline wash, the acid wash or rinse, the
last post-rinse, and on completion of the final rinse. The water required to“fill” the
CIP S/R piping, and create aminimum puddle in the vessel being cleaned becomes
greater as the distance between the CIP skid and the vessel increases. The first cost
for asecond CIP skid may be recovered quickly by reduced water cost for daily
operation when the S/R piping contains significantly more water than the piping
actually being cleaned.
Scheduling
Scheduling criteria must address not only the number of circuits, but also the
frequency of cleaning. Consider, for example,
& How many lots are made on adaily basis?
& How many batch operations and transfers will be made daily?
& How many product changeovers occur in agiven period of operation?
& How available are cleaning utilities, especially water?
A major consideration involves the philosophy of CIP to be applied.
Alternatives include:
& Maximum flexibility, and the ability to clean any vessel, or any transfer line or
other equipment item, individually, following each period of use
& Recognition that each vessel isused for abatch process associated with a
subsequent transfer operation. Creative engineering design can makeitpossible
to clean the vessel and all associated piping and downstream equipment involved
in the transfer in asingle circuit, thus reducing the number of circuits by a
factor of as much as three, comparedtothe moreconservative, flexible approach.
The writer recommends consideration of computer simulation of the chosen
method as the means of reaching afinal decision. Computer simulation can provide
design data on which to base the decisions about the number of CIP systems
required,the total time each will operate during a24-hour day,the amount of water
required, and waste to be generated, and the estimated chemical utilization.
Consider also that CIP skids and associated CIP S/R piping used at areasonable
level of activity are less subject to developing contamination during long periods of
nonuse. It is also not advisable to design for aCIP system usage of above 70% to 80%
on average (Fig. 2).
Redundancy
Astate-of-the-art CIP skid is acomplex assembly of equally complex components
which will occasionally fail, and require maintenance and the subsequent testing and
documentation. Downtime considerations are essential, especially if multiple
process areas are dependent on asingle CIP skid. Redundancy can be achieved
by two CIP skids, by routing CIP S/R lines through mix-proof valve arrays or
transfer panels.
Careful consideration of segregation, scheduling, and redundancy needs,
during the conceptual design phase, will enable the design team to define the
system needs. Recognition of the value of the CIP system as a“start-up tool” is also