Descaling of Plate & Frame Caustic Heat Exchanger

1: Discuss the cooling water treatment regime with the supplier of the treatment chemicals. Discuss the exchanger performance with the original equipment manufacturer.

2: Consider stripping-out the exchanger for a deep chemical and mechanical clean, and then reassemble.

3: Consider increasing the number of plates in the exchanger.

good answer, especially #2, actually all most of them

we have material running through our plate HX's where fouling is a problem and normally CIP just doesn't cut it. We have to wash the plates by hand.

On number #3, by adding more plates, don't you reduce the flow rates through the plate decks where possible creating a laminar flow..?

(ΔP would be reduced some what also)

But also contacting the Chemical Rep. for recommendation would be prudent.

4. Investigate and rectify sources of unexpectedly low flowrate in the cooling water system.

https://www.wcrhx.com/heat-exchanger-plate-cleaning

Thanks for the answer guys.

Lower CW flowrates (at some times) ...hmmm this can be the problem which needs remedy because CW inlet pressures aren't logged at DCS. Thanks

Increasing # of plates cannot be justified because the required performance was being achieved since 2011.

Taking out HXchanger will cause production loss ...which though is an option but not currently when caustic prices in international market are at peak. Thus I am looking for insitu solutions

I did add CW specs to make it comprehensible what may be the kind of fouling we are dealing with.

<... what may be the kind of fouling...>: 3 kinds -

1. Biofouling
2. Chemical deposition
3. Corrosion
4. Some combination of 1-3

If <...Taking out HXchanger will cause production loss...but not currently when caustic prices in international market are at peak...> then one may assume the following:

1. Off-spec product is acceptable, and therefore the production specification needs widening to accommodate that which can be manufactured, thereby removing the concern.
2. There is no justification for installing duty/standby <...HXchanger...> in parallel in readiness for the next time this phenomenon happens.
3. The problem is simply constrained beyond the point where a solution may be applicable.

The problem is simply constrained beyond the point where a solution may be applicable.

PWSLACK, were you writing this comment while reading Mathematics book on Stochastic optimization?

32% NaOH at approx. 75 C is a VERY good way of removing mild silica deposition- that is,if you can think of somewhere to get some.