MRC compressor seal air
Thread Content
The MRC centrifugal compressor uses process gas for sealing purposes. In the past few days, it has been observed that the flow rate at the high-pressure side has gradually decreased from 100 NM3/h to 85 NM3/h. The flow rate of the sealing gas on the low-pressure side remains unchanged at 100 NM3/h; all pressures are normal. What could be causing the decrease in the flow rate at the high-pressure side? Are there any risks? How to solve it? Seeking guidance
How can we determine whether there is an external leak?
It shouldn’t be; the pressure difference between the sealing gas and the balance tube remains at 0.2 kPa. A leak on the high-pressure side would likely be due to the sealing gas leaking into that side, right?
There are several possibilities: whether there is a leak at the high-pressure end, whether there have been any changes in the components, whether the measurements are accurate, and whether the dry gas sealing system is functioning properly
A dry gas seal creates a seal through the throttling effect between the gas film, the stationary plate, and the moving plate. You can check the information provided by manufacturers of dry gas seals regarding the range of sealing gas consumption; additionally, it is also related to the pressure difference. Generally speaking, in theory, as long as an air film can be formed between the moving and stationary parts, there should be no problem. However, it is essential that the fit between the moving and stationary parts of the dry gas seal be excellent.
A significant drop in flow rate has little impact on the compressor; however, a large decrease in flow rate greatly affects the stability of the gas film in the dry gas seal, which can lead to damage to the seal. Since the flow rate at the second stage of sealing is normal, it should not have much effect on the compressor. Fluctuations in the flow rate at the first stage may be caused by high back pressure or fluctuations in the pressure at the outlet of the compressor’s second stage
The back pressure is too high, or the sealing air pipeline is blocked