Still to remove water from ammonia refrigerant

[RJVan57]

When constructing a vessel to boil ammonia and separate it from water, IIAR Bulletin 108 specifically recommends against “the use of vessels containing internal coils through which liquid ammonia is circulated”. But the Bulletin does not say why. I presume the problem is that if the coil develops a leak, it will be very difficult to repair. Are there other issues?

Also, what if the coil circulates ammonia vapor? Would the same recommendation apply?

Any thoughts/insights would be appreciated.