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