Two considerations for the construction of liquid ammonia pipelines
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I came across an article that mentioned two points to keep in mind when constructing liquid ammonia pipelines: 1.1.1.1. When connecting tee joints in the ammonia system pipelines, the branch pipes should be bent into an arc following the direction of the ammonia flow before welding. 1.1.1.2. Welding of ammonia system pipelines should be carried out at temperatures above 0°C; if the temperature is below 0°C, care should be taken to remove moisture and frost from the pipelines prior to welding. Let’s discuss the reasons for these two points!
I think the first point mainly takes into account the stress corrosion issue in ammonia media； The second point is that the vapor pressure of ammonia-based media is relatively high, which helps to prevent dew formation and corrosion.
We have never seen such provisions; as for the second point, it makes even less sense – pipelines generally need to be preheated before welding, so that there is no water vapor present