The vapor equilibrium line of the storage tank? The head is very big
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I would like to ask an expert: For an MMA storage tank, there is one vapor equilibrium line that leads to the ship’s hull at the dock, with a valve at each end. What is the principle behind this setup during loading and unloading? What is the condition of the gaseous medium in the pipeline when operation stops? (If left in the pipeline, as the temperature drops, MMA tends to polymerize after liquefaction.) Is it required that the pressure in the storage tank and on the ship be the same, with nitrogen then being used to fill the tank or ship? (Addition: Nitrogen seal for internal floating roof tank is 140 mmH2O) This post was last edited by Song Qingshan on 2007-12-5 at 16:49.]
This issue applies to all liquefied gas propylene storage tanks; I hope experts can provide an answer.
An vapor equilibrium line from the MMA storage tank is connected to the ship’s hull at the dock, with a valve at each end. What is the principle behind this operation during loading and unloading? This now becomes a meteorological equilibrium line, used to balance the pressure issues in the input and output containers. What is the condition of the gaseous medium in the pipeline when operation stops? (If left in the pipeline, as the temperature drops, liquefied MMA tends to polymerize.) Under normal circumstances, after the equilibrium process is complete, the system must be purged with a protective gas. Is it required that the pressure in the storage tank and on the ship be equal, with nitrogen then being used to fill the tank or the ship? Under normal conditions, the pressure in the output reservoir is slightly lower than that in the input container, which ensures smooth return of the fluid. (Supplement: The nitrogen seal for the internal floating roof tank is 140 mmH2O.) Supplement: There are several other methods available, such as creating a vacuum under atmospheric conditions or using forced balancing to ensure equilibrium in the pressure during material loading and unloading