Regarding liquid feed
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Today, I came across a statement in a HAZOP analysis report that read, “Vacuum feeding of liquid feed is not allowed; positive pressure feeding should be preferred as much as possible.” Let’s discuss the reasons behind this
That sentence is funny – no vacuum, no positive pressure, only feeding under conditions of zero pressure?
Liquid vacuum material suction devices – I’ve seen many of them.
It is for security reasons. The components of the mother liquor should be flammable, explosive, and low-boiling-point liquids. (This proposition is problematic if it involves an aqueous solvent.) Vacuum feeding will vaporize a large amount of the mother liquor solvent, and the flammable and explosive vapors released at the vacuum pump outlet can create an explosive environment. Positive pressure feeding has the same problem. Pumps are generally used to feed the material, which results in the least amount of non-condensable gas being discharged. Additionally: Vacuum pumping can create a full vacuum in the liquid receiving tank at once, allowing the required material to be drawn in all at once; afterward, nitrogen is used to break the vacuum and then the tank is emptied.
Can we expand on this discussion further?
What the original poster is referring to is probably the prohibition against pumping vacuum while feeding material, as well as the prohibition against feeding material when there is positive pressure inside the tank that requires feeding I have indeed encountered situations where vacuum feeding was not allowed, and it was the local environmental protection agency that imposed this restriction.
I’d like to respond to the question about the materials from the floors above. Recently I’ve been studying HAZOP-related topics, and my supervisor gave me a bunch of materials; in one of the analysis reports, there was a sentence stating that since it was company confidential information, the properties of those materials were hidden. That’s why I’m posting this here to get everyone’s opinions on it
It’s because there’s a concern that volatile materials might evaporate, and such evaporation can lead to safety accidents. Whether under vacuum or positive pressure, it’s easy for these materials to evaporate