First pre-cooling of the ethylene sphere tank.
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The weather pre-cooling has been completed for the ethylene sphere tank prior to its first operation or after maintenance; it is possible to carry out liquid-phase pre-cooling by repeatedly opening and closing the feed pneumatic valve, with the tank base valve kept slightly open. Is it possible to use pneumatic valves that open and close frequently?
It doesn’t matter how you operate it; what’s important is to use the designed temperature of the ethylene tank as a reference during pre-cooling – this is the only standard. As for how to ensure that the temperature is not too low when the ethylene tank is put into use, it essentially comes down to preventing liquid ethylene from entering the tank and flashing there; therefore, the pressure in the spherical tank should be increased in advance to the operating pressure. When the pressure in the ethylene tank reaches 2.0 MPa, pre-cooling is not necessary; simply opening the valve slowly during material collection is sufficient.
Once the gas phase pressure reaches 2.0, won’t the liquid phase vaporize instantaneously?
We all fine-tune it with manual valves! Also, the temperature difference between the top and bottom should not be too large!
At a pressure of 2.0 MPa and an ethylene temperature of around -35°C, how can it vaporize instantly? If it has all vaporized, how can it be stored in spherical tanks?
I would like to ask the original poster: what temperature can be achieved inside the spherical tank after gas pre-cooling?
-10 degrees Celsius, pressure 1.60 MPa, followed by liquid-phase pre-cooling.
I use a slightly open canister root, with a pneumatic valve for adjustment. Its performance is better than that of a manual valve. The temperature drop curve is also quite stable
This post was last edited by hnan on 2017-10-15 at 11:18. The operating pressure of 1.6 MPa is too low; ethylene will definitely flash when it enters the tank. It is recommended to increase the pressure to 1.9–2.0 MPa.
The designed pressure is 2.20, while the normal operating pressure is 1.65–1.75.:
Liquid-phase pre-cooling is necessary to prevent localized low temperatures that could cause the material to become brittle at low temperatures