Heat Transfer & Thermodynamics engineering | Forum profile

P&F's are superior when close approaches are required.  If you don't need a close approach, S&T would be fine. Actually, P&F's came to us from the dairy industry where there was the requirement to take the equipment apart for cleaning daily.  S&T's just couldn't be cleaned to the dairy industries standard. But that said, that doesn't mean I...

If you could provide a drawing of your problem, maybe a we can find an analytical expression for it, a lot cheaper than those "expensive" 'bulldozer' programs.

rmw Thanks!! Super helpful. We've got a separate pump planned for the raw water, and our equipment generally runs continuous (23-24 hr/day) at full speed. So I think we'll be ok. I'm not sure how close we are to being as dirty as the Miss but it would probably be comparable, and with the cyclonic filter we'll get the majority of the particulate.

( The simple solution is to use a convection coefficient compatible with the expected temperature.  The resultant numbers will be "close  enough" since many assumptions that go into the calculations are not always valid anyways.  A 50?C change in the surface temperature should result in about a 6% change in convection coefficient , )

srfish, I agree with you. In my previous post dated 21st December, I suggested the OP to follow 25362's approach. In a broader view the classical method to calculate the LMTD (i.e. that which leads to LMTD = 91.8 ?F) when dealing with complex HX doesn't work.

( IRstuff, Thanks. Rth2, my mistake. Would it be correct to say that you agree that the thermal resistance will change with temperature?  And if so, do you feel \(gut reaction\) that it will influence the calculations enough to pursue?  Typically the temperature rise that I'm reffering to is about 100C. , )

Wish I could help you with stories, but I've never used these types of exchangers with anything other than clean process fluids.  Good luck!

( Schick: P+F = Plate & Frame \(Alfa-Laval, etc.\) Sulfur solids would be those that would typically be picked up by cyclonic separation \(Krebbs etc.\).  Not sure how big they are individually on average, other than they are quite visible to the naked eye. Please be cautious with my advice.  I don't see any real busts in your propose application, but there are several folks on this site who are...

Point taken... thank you. Oh, and the 8% penalty for burning NG should be ~4%.  It's the DIFFERENCE between the LHV/HHV of NG vs oil.

Rod baffles are essentially "no baffles", they are only there to support the tube bundle and not to direct the shellside fluid.  The benefit is low pressure drop, but the danger is maldistribution.  You must take care of the distribution in your design - by putting nozzles on opposite sides of the shell (one up one down, for instance).  The flow is directly countercurrent, but...