applied with high pressure jet water
pump. Occasionally, the corner point of
the shell and tube heat exchanger is the
toughest one to be cleaned and cleared.
A spiral heat exchanger on the other
hand can only be cleaned via CIP only.
There’s no way of it to be dismantled as it
is constructed in such a way like a spiral.
Each layer of stainless steels is welded and
thus if there is a tiny leak, the spiral heat
exchanger could not be used anymore.
Q4: W hat are some best
practices you can offer
end - users in the areas of
specification , installation and
maintenance of plate heat
exchanger technology to ensure
long - term performance ?
A: There are a few best practices that have
been applied. Among them is to make
a preventive maintenance schedule.
By doing this we can stop the PHE at
certain time and let the process runs on
a standby PHE. CIP can be conducted
if the scale or fouling is not too bad. A
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PECM Issue 30
CIP need to be carried out in a proper
way and the engineer in charge should
design a suitable standard operating
procedure (SOP) especially for the PHE CIP.
Otherwise, a major maintenance service
must be carried out which is to dismantle
the plates and clean them and then install
back the clean plates into the PHE.
Another point is to take the inlet and
outlet temperature and pressure as well
as the flow rate reading of the PHE. This
needs to be done consistently on a daily
basis. From this exercise, an engineer or
supervisor can monitor the trending of
temperature drop and detect whenever
the PHE performance is deteriorating.
For a relatively advanced monitoring,
a process engineer can calculate the
U-value (overall heat transfer coefficient)
of the PHE and assess the performance
of the PHE based on it. To make it more
interesting, this data can be captured
from the PLC/SCADA, program and
formulate it and make the U-value
appear in the SCADA. Supervisors and
plant operators can easily detect the lack
of performance when they notice the
U-value of any operating PHE is not up
to certain value. An alarm or indicator
can also be installed to make notification
automatic, instant and efficient. As soon
as the engineer and his team identified
an underperforming PHE, he or she can
assess and instruct the PHE to undergo
CIP or plate replacement. If there is other
maintenance work to be carried out, it
also can be done at that time.
Q5: W hat are some pitfalls
you see end - users commonly
encounter in plate heat
exchanger applications ? H ow
can end - users best avoid and /
or respond to such applica tion
pitfalls ?
A: There are situations where the hot fluid
and cold fluid flow rates are not balanced.
This situation normally occurs during
plant start up, plant shutting down or
plant failure etc. When this occurs, the
plate’s pressure will not be balanced and
leaking can likely occur. The best way to
overcome this is to have better control of
both fluids’ flow rate. The flow rate need