The issue of design pressure for liquid ammonia storage tanks
Thread Content
The design pressure of the liquid ammonia storage tank is 2.16 Mpa, and the design temperature is 50°C. Would it be okay if we use an ammonia compressor with an inlet pressure of 1.6 Mpa and an outlet pressure of 2.4 Mpa? Could the liquid ammonia tank experience overpressure? In other words, if we choose an ammonia compressor with an inlet pressure of 1.6 Mpa and an outlet pressure of 2.4 Mpa, what should be the design pressure of the liquid ammonia tank?
Another question: Is it necessary to install a nitrogen seal for liquid ammonia storage tanks?
The compressor outlet pressure exceeds the design pressure of the storage tank; this should not be allowed. Also, the inlet pressure is 1.6 MPa – shouldn’t it be lower than that? At such high pressure, above 40 degrees Celsius, it becomes liquid ammonia. Such a low compression ratio? A pressure vessel with such a high internal pressure and its own saturated steam does not require nitrogen sealing.
The original poster didn’t explain clearly; if the compressor outlet is connected to the liquid ammonia storage tank, the design pressure will be insufficient. If the compressor inlet is connected to a liquid ammonia tank, the design pressure will be sufficient; meanwhile, the storage tank needs to be checked for negative pressure.
The compressor inlet is connected to the liquid ammonia storage tank, and the outlet is connected to the tank truck. I still don’t quite understand; could it be that the pressure at the compressor outlet is 2.4 Mpa, and after passing through the pipeline in the tank truck, the pressure drops to below 2.16 Mpa?
I think since it’s a liquid and not a gas, there should be no problem
Unloading of liquid ammonia from a tank truck to a storage tank?
It seems the original poster did not explain this operating condition clearly. If it is about unloading liquid ammonia from a tank truck into a storage tank, then an ammonia compressor with an inlet pressure of 1.6 Mpa and an outlet pressure of 2.4 Mpa should be used. This compressor draws air from the liquid ammonia storage tank, compresses the ammonia, and then sends it back to the tank truck, thereby pushing the liquid ammonia in the truck into the storage tank. This should not cause overpressure in the liquid ammonia tank. Nitrogen sealing is typically used in storage tanks at atmospheric pressure; ammonia tanks do not use nitrogen sealing.
If the poster is unloading liquid ammonia, the gaseous stream from the ammonia compressor outlet should be sent to the tank truck. The design pressure for such tank trucks is generally around 17 bar, so the outlet pressure of the ammonia compressor is on the high side. As for the pressure in the storage tank, no other impacts have been detected for now
It’s for unloading liquid ammonia – so what kind of ammonia compressor is this? It’s simply a liquid ammonia pump!