Negative pressure airtightness of hydrogenation unit

What does negative pressure airtightness in a hydrogenation unit mean, and what are its functions and purposes? Negative pressure airtightness is also a type of airtightness; it depends on the ability to maintain airtightness under negative pressure. The goal, of course, is to ensure airtightness. Following that, nitrogen is often used to break the vacuum – nitrogen is used for displacement. What are the precautions to take during such operations? Pay attention to the isolation of instruments ； The airtight system is isolated from other systems. What pressure level is appropriate to achieve? (As the name implies, it involves creating a negative pressure seal; by drawing the system to a negative pressure level, wouldn’t that damage the equipment and pipes? I’m really confused about this, so I hope everyone can provide some guidance, preferably in as much detail as possible.) Of course, the lower the negative pressure, the better – generally, it’s set at 660 mm of mercury. Negative pressure airtightness is generally only used in high-pressure systems. If there are no issues with the pipelines and the equipment is designed to handle negative pressure conditions, then there’s no need to worry. If you’re still unsure, check the equipment diagrams for confirmation. It seems you’re a beginner; if you’re unsure about the operations, go and check the design documents.

Negative pressure of seven meters is generally not needed; refineries usually do not have air separation units, and there is a shortage of nitrogen. By creating a vacuum, nitrogen can be replaced more quickly, thus saving resources.