Are low-temperature ammonia tanks generally double-walled or single-walled?
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For one project, the ammonia tank area was initially planned to use 2 spherical tanks with a capacity of 5,000 cubic meters each, or 2 low-temperature double-walled arch tanks of the same capacity; however, it was decided to use 1 single-walled tank with a capacity of 10,000 cubic meters. I would like to ask if there is any technical support available at the moment? Are there any relevant specifications (I can’t find them)?
The use of low-temperature tanks is primarily driven by safety considerations. Of course, ammonia has a higher density at lower temperatures; as a result, for the same amount of ammonia, spherical tanks require significantly more steel for storage. In the past, double-walled tanks were generally used, mainly because the insulation materials did not provide sufficient insulation. With technological advancements, single-walled tanks are now used, as they allow for significant cost savings. Therefore, single-wall tanks are the preferred choice for low-temperature ammonia tanks.
The factories I’ve seen generally use double-walled cylindrical ammonia tanks, mainly for reasons of insulation and structural strength of the tank. If the aforementioned issues can be resolved, single-walled equipment can also be used to reduce initial investment costs.
The safety factor of a double-layer cryogenic tank is higher than that of a single-layer one, and the total investment required for two 5,000-cubic-meter spherical tanks is certainly higher than that for a single cryogenic tank. So when you choose a low-temperature double-wall tank, you must also have made comparisons in these aspects.
It is recommended to use a double-wall, single-volume tank, in accordance with EU standard EN14620 or API620 along with its Appendix R
Atmospheric pressure ammonia tanks are generally double-walled cylindrical tanks, with a perlite filler in the interlayer; two units of 5000 capacity each are designed primarily for cleaning the ammonia tank without shutting it down.
What we plan to build is a low-temperature single-layer tank with a capacity of 10,000 cubic meters. Our management used to think it would be double-layered, but the drawings provided by the design institute showed it as a single-layer tank...
As a supplementary note, the latest standard for double-wall tanks is API625; it is a standard specifically formulated for double-wall tanks and serves as a supplement to API620
What is the insulation performance of single-wall tanks? How is heat preservation achieved?
Do all ammonia storage areas require cryogenic tanks? Do cryogenic tanks need refrigerators to maintain the temperature? Are refrigerators generally made using ammonia or Freon? Is there any use of lithium bromide as well?