Plate heat exchanger - pressure surge, damaged seal

[arvert]

Hi,

The seal in the plate heat exchanger we are using got damaged when there was pressure surge on the sea water line. The equipment has since been replaced
and we have installed pressure reducing valve upstream of the cooler that reduces the pressure to 2 bar. The problem is when seawater cooling stops and
pressure drops, the valve opens. When the seawater is started back up the pressure comes so fast it just by passes the reducing valve and hit the cooler.

We are working on some ideas like installing pressure safety valve, re-designing the system with higher operating pressure to account for the unusually high pressure surge, etc..

I was hoping if anyone of you have encountered similar issue with this equipment and if you would be kind enough to share thoughts/ideas regarding this.

Thanks a lot.

 

[BigInch]

Design for the higher pressure certainly works.
Pressure control valves must act very fast, so often they can be too maintenance intensive at shutoff pressures, or too sensitive at operating ranges, or just don't work if you can't make them respond in time.

A relief valve will protect the system, but can be complicated with the problem of handling the relief volume which must be directed to vents, blow downs, or surge tanks.

You could try adding a slow starter to the pumps, or starting the pumps against a partially closed throttle valve (not a ball valve), then open them up slowly until normal flow is established.

 

[arvert]

Thank you BigInch for your insight.

 

[bimr]

In addition to BigInch's comments, you may consider adding a valve with closing speed adjustment.

 

[georgeverghese]

How about switching out to all welded plate heat exchangers - you can use wide plate width option if you need, and add on a guard strainer for all feedstreams going into the HX?