Anybody used welded plate heat exchanger in amine system? 1

[qurashifd]

We are in a process of installing a new lean/rich exchangers in our Amine (DGA) units. It was proposed that we use welded plat heat exchangers. However, we have no experince with those whatsoever. Does anyone has an experince with them? Any concerns?

 

[Montemayor]

qurashifd (Chemical):

I've never heard of a "welded plat heat exchanger"; I've used Plate Heat Exchangers (PHE) in MEA service, and I presume you mean a PHE that is welded as opposed to being gasketed.

I don't know why you would specify a welded unit. It's going to be a nightmare when it requires cleaning. With the appropriate gaskets, you should have no problem containing the DGA. I don't consider DGA a "hazardous" solution, so I fail to see the importance of employing a welded unit. The only concern I would have is the correct gasket material. The PHE fabricator can help here, especially if he warrants the service. A 316ss Plate PHE unit should work well, if properly specified and warranted.

Art Montemayor
Spring, TX

 

[flames]

We use welded plates in amine service. The set up is every other gasket is eliminated and replaced with a weld. In this arrangement we have the rich amine between two welded plates (a set) and hot lean amine between the sets of welded plates (contained with a gasket).

What we have is severe service in our amine systems (two different services, MDEA as well as sulfinol). We tried many different types of gasket material and nothing would really stand up to the relatively warm rich amine. We were getting mean time between failures of <6 weeks on eight exchangers that have over 400 plates each. The cost of running the exchangers was killing us.

We got EPDM to work a while and then switched to AFLAS gaskets which worked alot better. We then switch to the welded plates to eliminate the gaskets from the rich amine altogether. The result is that we have mean time between failures of almost 4 years now.

We have relatively few concerns with the welded plates. We got into some problems lately with a flow induced vibration due to our high level of two-phase flow, but we worked with our vender to redesign the plates which will hopefully solve that issue.

If you need more information leave your email.

 

[qurashifd]

Thank you very much both.

Flames, I would like to know what are the few concerns you have with them and why the mean time between failures is only 4 years?

From maintenance and inspection point of views, If you have the choice between welded plat heat exchangers and shell and tube which one would you choose?

e-mail: qurashifd@yahoo.com

 

[NickelMet]

You may want to check out the API document: &quot;API 945 - Avoiding Environmental Cracking in Amine Units&quot;.

~NiM