How to absorb ammonia gas in front of a vertical reciprocating vacuum pump
Thread Content
Dear teachers, please help. When the system is under vacuum pumping, a significant amount of ammonia enters the vertical reciprocating vacuum pump, causing the oil inside the pump to emulsify. This accelerates the wear of the piston rings and prevents proper vacuum creation. Is there any way to ensure that ammonia is fully absorbed before it enters the pump? If liquid absorption is used, what should be done with the absorbent liquid? What if solid absorption is used? How should it be handled? Thank you!
No reply? Is anyone there to help?
An oil-free piston pump will suffice
Add an absorption tower at the front; water can be used for absorption. Gas-water separation facilities should be installed behind the tower or at its top.
I agree with what was said above; adding a pre-stage absorption unit is an option, and the specific approach depends on your process requirements. Whether adding an absorption tower will affect the vacuum level depends on the circumstances. Generally, vertical reciprocating vacuum pumps are used in processes that require high and stable vacuum levels.
Ammonia is highly soluble in water; 1 volume of water can absorb 700 volumes of ammonia gas. By properly designing the absorption tower, the resistance can be kept within acceptable levels. For packed towers, I have used them for gas washing at a pressure of 1 millimeter of mercury, with a resistance of about a few millimeters of water column
I think it’s better to switch to a vacuum pump; oil-free piston pumps are more mature and widely used. Adding an absorption tower is not just a matter of increasing resistance. Due to the need to maintain a certain pressure in the process system, this inevitably leads to an increase in the vacuum level at the inlet of the vacuum pump. As a result, the load on the vacuum pump changes (with the level of load increasing or decreasing depending on the ammonia content). If the load increases, it may no longer be possible to meet the requirements of the process. Another issue is that the absorption tower may generate mist entrainment, which can enter the vacuum pump and potentially cause the oil in the vacuum pump to emulsify. Adding absorption towers also increases the process and production costs, as well as complicating operations.
Is the vacuum level very high? If it’s not high, considering switching to a water ring vacuum pump is also an option.
The vacuum level required is not very high; generally, the pre-pump of the vacuum unit is sufficient to meet the needs. Currently, 2SK-6A water ring pumps are being used; the water is recycled, which results in an increasing concentration of ammonia. The strong ammonia smell makes it difficult to handle this ammonia solution, and it is also hard to sell. The working conditions for the workers deteriorate, which is harmful to their health, and these conditions do not meet the standards of 18001. When testing the WLW-50 (B) vertical reciprocating vacuum pump, oil emulsification occurred, resulting in no vacuum. I’m ready to hear everyone’s suggestions and inquire with the manufacturer about the performance of oil-free reciprocating pumps. Thank you all!
It would be best to start from the processing perspective: is it possible to degas before distillation, to remove all the ammonia gas before carrying out the distillation? Ammonia is absorbed by sulfuric acid to form a salt, making subsequent processing simpler