Discussing the evacuation using a bottom-reduction pump
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Our pressure relief system is equipped with three bottom discharge pumps, two of which are variable frequency while one is at fixed frequency. These pump mechanical seals leak frequently, and they tend to get evacuated easily, resulting in fluctuations in the liquid level at the bottom of the tower. I would like to ask the experts about the reasons for this issue and some good solutions. Thank you!
Finally, it’s possible to build the sofa now, haha. Back to the topic: the temperature at the bottom of the system is relatively high. If there are frequent leaks in the mechanical seals, it would be advisable to consider using seals of better quality and greater durability, such as those from joint venture brands like Borgman. You really get what you pay for – there’s no alternative! Additionally, it’s necessary to consider the reasons for vacuum formation in the pump from the perspective of changes in the raw materials. Unstable properties of the oil are the main cause of vacuum formation in pumps. It’s unlikely that all three pumps have problems; thus, pump-related issues can be ruled out. It’s important to consult with the process engineers to check whether there have been any changes in relevant process parameters and whether there have been significant fluctuations in the properties of the oil.
Problems with the low-pressure pump not being able to deliver fluid in the vacuum distillation tower: http://bbs.hcbbs.com/viewthread.php?tid=197808. Methods and measures to prevent vacuum conditions in the bottom pump of atmospheric and vacuum distillation units during winter: http://bbs.hcbbs.com/viewthread.php?tid=339586&highlight=%BC%F5%B5%D7%B1%C3
The bottom-reduction pump fails to deliver sufficient flow for the following reasons: 1. Design issues: The clearance height from the pump inlet to the vacuum tower is too small, preventing it from overcoming suction resistance and meeting the required suction capacity... 2. Operational issues: Excessively high temperatures at the bottom of the tower, excessively high vacuum at the top of the tower, or unstable operation can all result in a low density of the liquid at the pump inlet; as a result, the pressure generated by the liquid column in the pump inlet is not sufficient to counteract the backflow force caused by the vacuum at the top of the tower, making it difficult for the pump to deliver adequate flow... 3. Equipment issues: Poor-quality mechanical seals can lead to leakage due to high temperatures, thereby reducing the pump’s efficiency... Which in turn prevents it from functioning properly in pumping liquids... :lol 4. Pipeline issues: Blockages somewhere in the inlet or outlet (or clogged filters)... etc. This post was last edited by wangsc on 2009-2-6 00:54
Could the evacuation caused by a bottom suction pump be related to leakage at the inlet seal? Is the pressure in the sealing chamber of the inlet mechanical seal negative? Will air enter through this, resulting in insufficient flow rate in the pump?
It is very likely that the filler has fallen into the filter; please check the filter.
It is recommended to check the address provided on the 3rd floor; it should be able to solve the problem you mentioned
We are currently using the AY type. What I would like to ask is: which side of the sealing chambers at both ends of the pump has negative pressure, and does that have an impact on the vacuuming process? Thank you
1. Please tell us the net distance from the inlet of your bottom suction pump to the normal liquid level at the bottom of the reduction tower. . . To determine whether it is due to design reasons. . . 2. Please tell us the bottom temperature reduction and vacuum level. . . To determine whether it is an operational issue. . . 3. Please tell us the type of mechanical seal and the manufacturer. . . To determine whether it is a pump leak or the general level of actual efficiency. . . 4. Please arrange to check on your own whether the pipelines and their accessories, including automatic control valve assemblies, are unobstructed. . . :lol
1. Vacuum level: 96.7 KPa; temperature at the bottom of the tower: 368°C. 2. Mechanical seal; the manufacturer is Dandong Klon. 3. The pipelines and control valves are in good condition. 4. The liquid is drawn from the bottom of the tower to about 5 meters from the pump inlet. Additionally, the bottom extraction pump sometimes experiences vacuum conditions, but its performance remains good in such situations!
1. The reason is the fourth one. . . The pump installation height must account for the combined resistance of a vacuum of 96.7 KPa, pipeline resistance, as well as the resistance posed by valves and fittings. Typically, the distance is determined by engineering firms to be the length from the tangent line at the bottom of the tower to the inlet surface of the pump (in the case of AY pumps, the pump inlet faces upward); this distance is usually between 13 and 14 meters. Please verify these figures carefully. . . 2. The pump seal is a brand-name product. . . 3. The vacuum level is basically normal. . . 4. The bottom temperature of the tower is basically normal. . . 5. If the distance from the pump inlet to the source meets the requirement of an intake distance of 13–14 meters, then check the diameter of the pipeline leading to the pump inlet. . . Take measures to reduce inhalation resistance as much as possible. . . 6. Next, check the vacuum distillation range of the residue at the bottom of the tower. . . Check to see if any lighter components remain undevaporated. . . This results in the density of the material being too low and too light. . . 7. The inability to pump fluid is closely related to the piping configuration and the internal efficiency of the pump. . . :lol Last edited by wangsc on 2009-2-8 07:53 ]