Ammonia Storage Tank – Insulation Type

Forums Process & Operational Ammonia Ammonia Storage Tank – Insulation Type

Viewing 3 posts - 1 through 3 (of 3 total)
  • Author
    Posts
  • #48606
    Participant

      Hi, we are in the early stages of FEED for a new ammonia storage tank (API625 full containment) and are deliberating over insulation type. We’ve received a technical note from our contractor stating the advantages / disadvantages of external foam vs perlite insulation. Reaching out to see if anyone has operational history with a perlite-insulated tank. Specific queries we have are: a) Does the perlite lose its insulating property over time? b) Any known operational issues with perlite condensation / freezing and liquid accumulation in the annulus?

      #49174
      Participant

        Regardless of the insulating duty, perlite needs to stay dry to be effective. So, single wall tanks and cold boxes are purged with high purity N2 to maintain dryness. As long as the purge system is maintained, my understanding is that perlite will maintain its insulating performance for years cum decades of service. I’d expect some top up could be needed to account for some settlement over time but an experienced perlite supplier should be able to answer that question in depth. Plus, I’d expect that the smart move is to load a bit of excess to account for settlement.

        Refer here for one supplier’s explanatory detail:

        Check the video and note the use of an on-site furnace to heat the material and expand it to “switch on” perlite’s insulating properties. Think of corn being heated to become popcorn and its low density, high void:surface area.

        If you can source it, this paper:
        McGrath, P. & Tapp, P., Ice Removal from the Annular Space of an On-line Atmospheric Ammonia Storage Tank, 54th Annual Safety in Ammonia Plants and Related Facilities Symposium, 2009
        reviews the experience of dealing with wet perlite (that then sets solid) in the annular space of a single wall tank.

        If you’re thinking of external foam insulation then one key disadvantage that polyurethane foam (PUF) class of insulation carries is its flammability. Perlite is inert in that regard, so that’s a positive option. Another possibility is to use cellular glass, which from what I know is a better performer in terms of moisture resistance and without doubt, will not go up in flames like PUF. Downside of cellular glass is that it’s comparatively more expensive.

        #49177
        Participant

          Refer here for one supplier’s explanatory detail:

          Check the video and note the use of an on-site furnace to heat the material and expand it to “switch on” perlite’s insulating properties. Think of corn being heated to become popcorn and its low density, high void:surface area.

          For some reason that I can’t fathom, the forum software is not displaying the URL link that I posted (at least for me anyway), even though it shows up when quote the post.

          Just in case I’m not alone, the supplier and product I referred to is Imerys Cryolite 200. FWIW, I’ve got no affiliation with that company and have no idea whether their product is good or bad. However, they have posted a handy video that explains the process for onsite preparation for cold insulation use. That’s why I used it in the reply.

        Viewing 3 posts - 1 through 3 (of 3 total)
        • You must be logged in to reply to this topic.

        [user_registration_form id=”41351″]