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Any industrial experience with TEMA "F-type" shells with condensing service on shell side? What are the disadvantages? For a service with wide boiling/condensing range and temperature cross, can it be used?
 
Answers
11/03/2015 A: Farid Q Q, Indian oil corporation Ltd, faridulqadar@gmail.com
Although theoretically additional shell pass in F- type shell should augment heat transfer ( at the expense of increased pressure drop ) we generally dont go for it because of practical issues such as additional conductive heat transfer via the longitudinal baffle because of thermal gradient existing above and below the baffle, also the seals generally are not effective between the shell and the longitudinal baffle resulting in fluid leakage owing to pressure gradient between the two passes.
These factors reduce the MTD hence it is more prudent to opt for multiple shell in series in the given scenario.
27/02/2015 A: karthik ramesh, indian oil corporation, rameshkarthik810@gmail.com
We at Indian Oil Gujarat refinery also facing problems with the thermal performance of the F type shell in feed effluent exchangers for hydrotrater service. while simualting in HTRI hot end approach is 30 degC. but in the plant we are not getting less than 50 degC.
As per our experience thermal performance is poor for F - type shells and it is better to go for two shells of E type than going for F type exchangers
04/11/2014 A: Nagesh Bejgam, Reliance Industries Limited, nagesh.bejgam@ril.com
Thanks, Eric. I do agree issues of shell side fluid bypassing the bundle if the seal at the longitudinal baffle breaks during insertion or removal which is a major disadvanatage. Could not get why hydroblasting won't be possible if baffle is welded to the shell?
I did a bit of research and came up with following disadvanatages as well:
1. If the longitudinal baffle is not insulated, thermal leakage may happen across the baffle
2. For condensing on shellside , a liquid pool will be created over the baffle,which will act as a insulating medium to heat transfer
3. Chances of phase segregation in the bottom compartment
Could not get why hydroblasting won't be possible if baffle is welded to the shell.
29/10/2014 A: Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
I have seen F shells in hydrotreater feed effluent service. In this case I think that the condensing was on the tube side. The big risk with F shells is that the leaf seal can get damaged pulling the bundle in and out, which can significantly compromise the benefit of the F shell. If you can get away with not pulling the bundle to clean it, a welded in baffle on the F shell is a good choice but you have no way to hydroblast the shell side of the bundle. The example I sited had a mixed feed ranging from C5 through diesel. The exchangers were installed as part of a retrofit and allowed significantly improved heat recovery in a limited space since fewer shells were needed than with traditional E shells