Ace Duplex SS vs Cu Ni - Heat transfer efficiency of Duplex SS will be approx 75- 80% less that of Cu NI Hope this helps C.V.Srinivasan Sept 20 Nishi Engineers Pvt Ltd India E-mail; nishi@vsnl.com >Hi Metacomp, > >Sorry first, but I think you misunderstood my question. >We personally select duplex just to combat corrosion (both >from erosion & sulfur) and we are pretty sure that it will >perform well. >The main question for us is how about the thermal >performance? how big it will be affected if there is changes >from copper nickel to duplex? > >Kind regards, > >Ace

ACe If it is a new exchanger I would look at erosion-corrosion effect for the intended service (temp/pressure) and think of metallurgy to suit that first and then think of thermal transfer efficiency. So problem of a higher capacity exchanger with new tube metallurgy but with less heat transfer efficiency would automatically take care of both metallurgy / heat transfer problems with higher cost no doubt. If it is an existing exchanger where already tubes used (CU-Ni) have to be replaced due to problems of corrosion-erosion, then replaced tube metallurgy and its lower heat transfer parameters will be taken into account to consider operating a plant with lower thru put. Duplex cannot work at the same heat transfer efficiency as Cu-NI. So either design to hold more tubes or for the reduced heat transfer number of tubes in the same shell / tube sheet design will affect plant production to some extent. Decide on what is best suited to your plant at this stage Hope this helps C.V.Srinivasan Nishi Engineers Pvt Ltd Sept 20 E -mail nishi@vsnl.com >Thanks a lot Metacomp. >So, based on your explanation, what I have in mind for >solution is that I will add 25% more tubes to compensate the >thermal performance loss. >From your experience, how do you deal with this problem?