I would like to ask whether the methanol tanks equipped with nitrogen sealing use a breathing valve or a single vent valve.
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I would like to ask whether the methanol tanks equipped with nitrogen sealing use a breathing valve or a single vent valve. If the matching call valve fails and the nitrogen storage tank is still discharging liquid, won’t the tank get collapsed? !
A nitrogen seal valve is generally sufficient when paired with a single exhaust valve. In ordinary nitrogen seal valves, the valve opens fully when the inlet pressure is lost; therefore, air can flow in as long as the inlet is not blocked. If the valve for breathing is integrated, the intake of air into the tank can also pose a safety hazard.
What I mean is that there is a possibility of nitrogen leakage in the main nitrogen pipeline at our facility.
A single call valve will suffice. The nitrogen sealing system will automatically replenish it during discharge.
Is the entire pipeline closed or open after the nitrogen supply is cut off?
The higher requirement is to maintain complete sealing, that is, through nitrogen sealing and overpressure venting systems; even when the nitrogen supply is cut off, the tank remains isolated from the outside environment. The lower requirement involves installing a self-acting control valve along with a breathing mechanism to ensure a slight positive pressure inside the tank. The first approach mentioned is that used by Linde, while the latter relates to uncontrolled emissions, and it depends on local regulations
The nitrogen pipeline is closed, but there are many branches on the main nitrogen pipeline that lead to various workshops, where the nitrogen is used either for sealing circulation machines, as a gas for displacement, or as a raw material for ammonia synthesis. As a result, the nitrogen pipeline is quite complex; if the main nitrogen pipeline is severed, there is a possibility that other substances could enter.