Insulation for Flanges of Heat Exchangers
Insulation for Flanges of Heat Exchangers
(OP)
The medium through tube side is MP steam and shell side benzene. Channel barrel and shell barrel are insulated but the flanges beween them aren't. I think the flanges should be insulated for heat conservation and even personnel protection. But the equipment engineer said it would be not convenient for maintenance and not easy for finding leak and even increase the external corrosion if they were insulated. It seems a little reasonable and I am a little confused now. Could anyone give some suggestions for me? Thanks a lot.





RE: Insulation for Flanges of Heat Exchangers
Offshore Engineering&Design
RE: Insulation for Flanges of Heat Exchangers
RE: Insulation for Flanges of Heat Exchangers
RE: Insulation for Flanges of Heat Exchangers
Why are most of them uninsulated? Could you provide appropriate reasons for that from the aspect of design? Thanks.
RE: Insulation for Flanges of Heat Exchangers
Another reason that I'm aware of for keeping flanges uninsulated is that if the process fluid contains hydrogen, it will diffuse through the gasket. If there is an insulating cover, hydrogen can build up in the enclosure, leading to the potential of an accident when the cover is removed.
RE: Insulation for Flanges of Heat Exchangers
RE: Insulation for Flanges of Heat Exchangers
1) Process engineering specifies insulation on flanges for heat conservation
2) Heat exchanger is installed and in service with insulated flanges
3) Maintenance is performed that requires breaking of the said insulated flanges- If rigid insulation- it's normally damaged beyond repair at this stage.
4) Maintenance is complete and flanges bolted back up without insulation
5) Some time passes..............
6) Energy efficiency review identifies heat losses - potential to improve plant efficiency by insulating all those nasty hot flanges
7) Insulation is applied to flanges
8) Go to step 3)
RE: Insulation for Flanges of Heat Exchangers
itdepends: what are you claiming is damaged beyond repair: the insulation, or the exchanger?!
RE: Insulation for Flanges of Heat Exchangers
I've collected atmospheric pressure hydrogen (high school experiment with electrolysis), and even a few milliliters will create an unpleasant explosion.
Most of the refineries and upgraders that I've worked at or worked for have specific requirements for NOT insulating flanges in services with high hydrogen partial pressures. In the course of asking about these requirements, I have inevitably found that this has come about because of either a near miss or an injury incident involving hydrogen accumulation in an insulation "box".
RE: Insulation for Flanges of Heat Exchangers
Your insulators are to be commended if their cladding is hydrogen-tight against diffusion losses THROUGH an intact gasket!
I can see the cladding concentrating gross leakage from flanges, but it would need to be quite a large leak, and I trust your normal hydrogen handling procedures would prepare workers to detect such a leak. This sounds like another argument for the sewn removable jackets I suggested to the OP- they're definitely more vapour-permeable than aluminum or stainless cladding. They're also far easier to remove, and far more likely to be correctly re-installed, than clad insulation covers.
RE: Insulation for Flanges of Heat Exchangers
However, given the benefits of a cooler bolt, I would still tend to not want to insulate flanges that operate warm/hot. The additional gasket contact stress caused by the cooler bolts can often negate any gasket creep that may occur.
RE: Insulation for Flanges of Heat Exchangers
RE: Insulation for Flanges of Heat Exchangers
Regards,
Mike
RE: Insulation for Flanges of Heat Exchangers
We build small plants, and if we didn't insulate the flanges you couldn't keep things hot enough to operate properly. Then again, the consequences of a leak are less dire.
RE: Insulation for Flanges of Heat Exchangers
Cheers.
RE: Insulation for Flanges of Heat Exchangers
Has anyone dealt with this before?