Actually you are answering your question. Your concern regards the chloride level at the water boot (100 ppm) so, If I am the corrosion engineer at your plant I will never recommended to install any type of stainless steel at all the crude unit. The crude unit It suffer from chloride contents if you are going a long with this recommendation to install SS ferrules you will face SCC (CHLORIDE CRACKING) . You know because you refinery group think the SS will be provide good resistance h2s and forgot the chloride effect. If your tubes is carbon steel just I recommend you to do the following: • Fabricate tubes insert (cs) • Using the wash water at the fin fan header at least I hr a week to remove deposit. Really amazing thing you have 100 ppm is very strange and difficult to imagine are your overhead line condition is fine. I think you have to give mote attention to the overhead corrosion because this amount of chloride will reduce ph and compete with HS to accelerate the corrosion rate. More help if your interested I will provided to you if you explain your system from the desalter until the overhead (provide the crude salt PTB and the water wash ph at the desalter more and more sure we will reach a proper solution). Note that: chemical injection quill at the overhead and caustic have to be Monel 400. Thanks Mark Mor Refinery Corrosion engineer

Mark Mor/Alex Ferrules help a lot to prevent inlet end corrosion conditions. Under stagnant conditions, galvanic coupling is a possibility. Duplex S.S would address to a great extent and resist Cl- environment problem. You should also recognize possibility of galvanic corrosion in stagnant conditions when system is down. Suggest weigh all possibilities before taking a final decision on material change and ferrule introduction. This includes small increase in velocity increase at the tubes at the inlet end due to ferrule. Suggest to look from this possibility. Suggest to inspect inlet conditions during major turn-around after removing ferrules for erosion -corrosion due to increase in velocity and also under stagnant conditions during down time. C.V.Srinivasan Nishi Enginees Pvt Ltd Chennai India July 06 E-mail: nishi@vsnl.com >Mark thanks to your involvement on this issue, before >explain the whole process on the plant I know the concern >using SS in Cl environment and I totally agree with you , >but I want discuss more about SS ferrules to present that >reasons to my group and convince them that SS ferrules is >not the solution. So I read the NACE 2005 paper 05571 about >the use of Duplex in refining enviroments and relating >API938C publication and presents Duplex SS good perfomance >in Chloride enviroments. What is your opinion? >Also I invite all forum members to get theirs opinions I >want hear from many others users. >Regards >Alex