I agree with your colleague - what were you planning for the lower tubesheet - an internal fillet?
Put a step on both sides of the lower tubesheet and weld as per an NEN design (Fig UW-13.2(c)(d)or (e-2)).
It may be possible to get pretty close by hand, using velocity heads. See https://www.chemicalprocessing.com/articles/2012/get-your-head-around-velocity-head/
A repad is not always required. See Fig UG-37.1. The missing material can be replaced in a number of ways - area available in shell, nozzle wall, inward and outward, weld fillet inward and outward.
Trebormech,
You may have uncovered a typo - they may have meant to say "are enclosed within a shell" since they allow higher allowable stresses, and they're referring to Sect 1 applications.
Hello,
Last year DK44 created a thread regarding drying of heat exchangers after fabrication and hydrotest (thread794-436465).
I have this requirement on a job I am currently quoting. I would like to know the solution that was used and any suggestions.
My requirement is 10 ppm of water. My...
DK44 - this is not an easy answer. A few considerations are:
- height under nozzle for distribution (plenum area)
- length
- nozzle size
- flow velocities at various points - in nozzle, in plenum above bundle, through bundle
- is there adequate pressure drop through bundle ("back pressure") to...
Miftahazhar,
Please tell us the fluids on shellside and tubeside. You can consult TEMA book to get recommended fouling factors to use based on this. Another approach is to design with a % clean. This is sometimes used by designers of surface condensers. An 85% clean for instance, would add...
kvbalu2011, you have not told us the tube length or the baffle spacing of this heat exchanger. The UHX calculation that SnTMan mentioned takes both of these into account to determine whether the heat exchanger can absorb the growth of the tubes, relative to the shell (+.179mm) without causing...
did you say that this shell and tube heat exchanger works fine - with a .3 deg C approach temp (cold water out to hot water in)?
I'd like to see that. Please provide details of the unit - tube size, shell size, pressure drop, etc. We don't quote anything closer than a 5 deg F approach, and as...
Is anyone sure what is required for Alberta CRN? The answer seems to depend on the reviewer, wind direction, state of the relationship with client...etc...
I think a more appropriate equation is 13.36 EE-6 mm/mm deg C x (300-21.1 deg C) x length of pipe, and then analyse this growth and see what that does to the pipe - make sure the stresses do not exceed allowable, add hangers, bends, etc, as needed. The pipe itself, if properly designed, can...
Look at the LMTD correction factor charts in your TEMA standards book, and if needed, break up the unit into two sections and calculate the correction factor separately for each section.
I've run into the same issue in the past, and we ended up making flanges, couplings, and plugs out of plate SB-171 C706. All the leads I had for finding 90/10 forged fittings were dead-ends or were not allowed per Code, as you mentioned for the SB-151 bar stock.
