Urgent! Urgent! Urgent! Emergency repair for reciprocating compressor failures? ? ?
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There is a nitrogen compressor in my workshop; during normal operation, the outlet pressure suddenly increased, causing the safety valve to activate (at 2.1 MPA), whereas the normal pressure is 1.7 MPA. During the shutdown for maintenance, 4 suction and exhaust valves in the second stage were replaced, and normal operation was achieved after restarting. Around day 5, the outlet pressure began to fluctuate between 1.7 and 2.0 MPa. Today, the primary exhaust valves and the secondary intake valve were removed again for inspection; it was found that both of the primary exhaust valves were leaking. These valves were promptly replaced. The secondary intake valve was a bit dirty, seemingly due to carbon buildup, so it was cleaned before being reinstalled. After restarting the system, the outlet pressure at the primary stage still fluctuated between 1.7 and 2.0 MPa. Could anyone help analyze what might be causing this issue? ? ? ?
The information is incomplete, making it impossible to conduct a proper analysis. It is best to attach the parameters and flowchart of this unit.
Based on the various analyses above, this is my opinion. I. The pressure at the outlet of stage 1 is normally 1.7 Mpa; currently it remains between 1.7 and 2.0 Mpa, which is above the normal level. Therefore, a problem with the valve at the outlet of stage 1 can be ruled out. Even the leak in section 1 of the outlet valve, which was detected for the first time, I think is also a minor leak that doesn’t have a significant impact. Because if there is severe leakage at the outlet of stage 1, stage 1 will not perform any work; and if stage 2 draws fluid in through its inlet, then the pressure at the outlet of stage 1, which is also the inlet pressure of stage 2, should decrease. The outlet pressure at stage 1 is high, so the issue with the outlet valve at stage 1 can be ruled out. II. Consider whether there are any issues with the two-stage inlet and outlet valves; leakage in either of these valves can affect the pressure at the outlet of stage 1. I think this is the main problem. III. There is another issue that needs to be checked. Why is the inlet valve in section 2 a bit dirty? Could it be carbon buildup? How can there be carbon deposits in nitrogen? Perhaps finding out this reason will resolve the frequent leakage of the valve. This is the essence of the handling. That’s how I’m thinking for now; please share more suggestions.
The black carbon buildup is caused by too much lubricant being applied to the O-rings and valve gaskets during valve installation, with dust sticking to them over time. I replaced all the air valves today, but the pressure at the primary outlet still fluctuates. Now, is it only the secondary piston rings that need to be checked?
1. The secondary intake valve can be opened for a third time to check it; if carbon buildup is severe, it is necessary to find and resolve the issue caused by the carbon buildup. Otherwise, even if the fault is not caused by carbon buildup this time, it will definitely occur in the future! If it’s very little, then it’s possible that the initial inspection wasn’t thorough enough! As for the reasons for excessive carbon buildup, it is necessary to consider the process media, but the possibility that oil injection could be the cause cannot be ignored either. 2. The safety valve has activated once – has it been inspected? Is there any internal leakage? 3. If nothing else works, pull out the piston to check the piston rings. That’s about it!
What is the primary inlet pressure? Calculate the pressure ratio; what are the inlet and outlet temperatures?
The analysis is fucking great. I’m done
Learned something new:victory:
Once it is confirmed that the gas valve is in good condition, check the wear of the second-stage piston rings as well as the degree of wear in the second-stage cylinder. From a process perspective, verify whether there are any pipelines leading from the outlet back to the first-stage outlet, and check for internal leakage in the valves. Also check the operation records to see if there are any changes in flow rate, pressure, and temperature at levels 1 and 2 compared to normal conditions Is there any pattern in the pressure changes? Let’s analyze it in more detail
It’s likely that there’s a problem with the two-stage valve. Does the machine have a one-back-one, two-back-two operation mode? Additionally, a stuck outlet check valve can also cause this