Are the three vacuum-evacuated atmospheric legs under positive pressure or negative pressure?
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Are the three vacuum-evacuated atmospheric legs under positive pressure or negative pressure?
Why must it be three? Will two or one work?
I understand the issue you're referring to; your vacuum system is three-stage. The atmospheric leg is under negative pressure; the vacuum created by the pump allows water (or oil) at the corresponding height to be drawn in, thus creating a liquid seal.
Negative pressure is primarily used to maintain a liquid seal and prevent air from entering, thereby avoiding accidents.
The poster can calculate this themselves: find out what the pressure in your water tank is, and also determine how high the atmospheric leg is; with that information, it should be possible to do the calculation
I’m not sure if it’s related to atmospheric and vacuum distillation units; it is said that three-stage vacuum extraction is commonly used in current designs. After the first stage of vacuum extraction, a negative pressure can be considered, while the second and third stages of vacuum extraction can result in a slight positive pressure
Negative pressure; therefore, a water seal tank must be installed below to prevent air from being drawn in
You can imagine what would happen if a part of the atmospheric leg were to rupture Does air go in or does water flow out? Think about it and you’ll understand!
It must be under negative pressure; take a close look at the waste oil tanks in your own refinery and you’ll see. The slight positive pressure mentioned upstairs refers to that inside the vacuum pump; after it comes out, it should still be negative pressure. The water level in the oil waste tank acts as a liquid seal. The three components mentioned by the poster refer to two stages of vacuum extraction; one of them is the condenser. Every time condensation occurs, the cooled liquid must be poured into the sludge tank. To understand this better, it’s sufficient to go to the site or take a look at the flowchart prepared by the design team – it’s easy to comprehend then
That one is an atmospheric leg; I’m not sure. Can you tell me?
It should be negative pressure; our company uses three-stage vacuum pumping, with a condenser after each stage. The oil tank below serves as a liquid seal. Our steam pressure is around -0.1 MPA