Analysis of the reasons why the impeller of rich gas compressor wears out and falls off
Thread Content
Recently, our plant's coking rich gas compressor made abnormal noises. The vibration of the compressor was accompanied by fluctuations, but the amplitude was not large. When the machine was shut down and disassembled for inspection, it was found that the second-stage first-stage impeller mouth ring air seal (material: 2A14) No more, impeller (material: FV520B-S) wears out and falls off. Please help me analyze the reason why the impeller is worn out.
It can be seen from the photo that the rotor is running in a clean environment. Regardless of the factors caused by foreign matter, the damage to this stage of the impeller should be caused by equipment quality problems.
Tips from the Design Institute: If there is only the first stage of the second stage, and if there are no problems with other stages, you should first consider whether the rich gas is carrying liquid (the cooling separation between stages is not completely removed), the speed of the liquid droplets is very high, and the impeller is worn. This caused vibration, causing the cast aluminum air seal to break. After the small droplets pass through the first stage of the second stage, they evaporate after impact and compression and heating, so that this does not happen in the following stages. It's just a guess based on experience. If it is solid particles, there will generally be problems with one section, and there will also be problems with the flow channel of the expansion chamber.
Quality issues are unlikely. The drum sinking machine is made of impellers made of a batch of materials. And this precipitation hardened stainless steel is very corrosion-resistant. The process is also relatively mature. From the picture, there are no problems with other stages, and the first stage looks like wear and tear, not a break due to quality issues.
The machine has been running for 4 years, and it should be due to wear and tear. The air seal teeth at both ends of the shaft have a lot of coke, and there is also a deep groove on the seal shaft at the low pressure end.
From the second picture, it can be seen that the impeller has fallen off from the hub. It is not just a matter of blade and seal wear.
It should be caused by wear, but can the wear of droplets be so severe? Are there any other possible reasons?
If there are particles, it must be caused by wear and tear. But it’s strange, the grinding was so severe, but there was no alarm in the early vibration? The balance piston seal is damaged like this.
A catalytic rich gas compressor of Yanshan Petrochemical has been in operation for 20 years. I can't believe it.