Liquid entrainment issue in the dry gas seal of centrifugal compressors

The oil pressure is too high, while the pressure of the isolation gas and the secondary sealing nitrogen is too low (below the oil pressure); measures should be taken to increase the pressure of these gases.

Firstly, when there is oil present in the vent stream, it is caused by liquid in the primary or secondary sealing gas (also known as buffer gas). This issue with liquid can lead to the failure of the secondary seal, which in turn results in increased leakage at the seal, manifested as an increase in vent pressure. Solution: Add a condenser to the primary seal gas supply, include a liquid separation tank, add a heater as well, and then pass the gas through a filter before it reaches the seal chamber ； There is also a possibility of oil presence in the nitrogen system, so that should be checked as well. If the above tasks are completed, the problem will be solved.

It is necessary to check the pressure difference before and after the isolation gas filter. A low pressure and low flow rate of the isolation gas can cause the bearing lubricant to enter the cavity behind the secondary seal and be discharged into the atmosphere along with the secondary leakage gases. Additionally, before starting the compressor’s lubrication system, it is important to ensure that the isolation gas is supplied and meets the required specifications.

I completely agree with what the guy on the third floor said. Such problems have occurred in our factory as well, and the solution is the same as what was mentioned above. You can take that into consideration

The reasons may be as follows: 1. Liquid in the secondary sealing gas and isolation gas can be addressed by adding buffer tanks, filters, and heat tracing systems to improve condensate removal. 2. If the amount of lubricating oil in the compressor is too high, adjust the oil injection pressure at the bearing shells according to the temperature of those bearings; it is generally between 0.08–0.13 MPa. 3. The injection volume of the secondary sealing gas and isolation gas is too low; it can be increased appropriately. 4. The carbon ring seal at the isolation gas injection point is damaged; increasing the amount of isolation gas injected appropriately can help maintain production. 5. The requirement to introduce isolation gas first and then lubricating oil was not strictly followed ； Start/stop procedure: stop the isolation gas first, then the lubricating oil

It is caused by insufficient flow rate of the isolation gas, or excessive oil and gas pressure in the bearings; it has little to do with the secondary seal gas. This post was last edited by jijhhg on 2008-11-27 20:11]

1. Check the pressure of the isolation gas. 2. Open the bearing housing and check whether the oil return hole on the outermost side of the dry gas seal is blocked. 3. Check that the drainage pipe of the bearing box is unobstructed to ensure a slight negative pressure inside the bearing box

Adjust the isolation gas pressure； Appropriately reduce oil pressure ； Increase the flow rate of the secondary isolation gas ； Check the isolation gas filter.

Isolated nitrogen with low pressure, or nitrogen containing oil and water

It might be due to liquid in the dry gas stream, or the pressure of the dry gas and the sealing oil pressure are not appropriate; adjustments are needed.

The oil contamination issue requires a thorough analysis of the entire system to determine what type of oil is the problem Is it lubricating oil for compressors, oil used to dry the gas being transported (such as triethylene glycol), or the impurities contained in the gas itself? Only then can a solution be determined. If confirmed, I fully agree with the analyses on the 3rd and 6th floors.

I tend to agree with the opinions regarding the 3rd and 6th floors. Additionally, on the 10th floor, \"Open the bearing box and check whether the oil return hole on the outermost side of the dry gas seal is blocked.\" ”This is also a reason that tends to lead to it easily.

It’s normal for a little oil to be present in the vent at the site, right? Bring ours too

3# HOULS71: Is there liquid in the sealing gas? It’s unlikely! Note: it is a dry gas seal! The process includes a fine filter with a filtration precision of 1 UM, which can filter out even water!

8# wlk2000, could you please explain what the exhaust pipe of the bearing housing means? What thing? Is it part of the bearing? How can micro-negative pressure be ensured? Is there an external power source for pumping?

14# peijie_jun – logically speaking, shouldn’t this contain any oil? I’m afraid it will get into the sealing surface and get damaged!

I think your dry gas seal is close to reaching the end of its useful life