Vibration in the outlet pipeline of reciprocating compressors
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I’ve been feeling a bit down lately – one of the reciprocating rich gas compressors in our plant is experiencing high-frequency vibrations in its outlet pipeline. This is a tricky issue for those responsible for equipment maintenance, and no cause has been identified from a process perspective. I would really like to ask everyone: what are the common causes of such phenomena? The equipment itself or the process operations
mainly look at the displacement; how about making the outlet larger and the return to the inlet a bit bigger?
Generally, vibration occurs at the inlet; vibration at the outlet is quite rare. But since it does occur, what could be the reason? I sincerely hope everyone can help and solve this mystery for me
Address the vibration first, as prolonged vibration can lead to unexpected issues. Solution: Add support to the outlet pipeline. Note that soft supports should be used for the braces, such as wooden supports. Then quickly find the cause, which can be done in conjunction with the process team. Let’s see by adjusting some operating conditions.
Support Floor 5! Vibration is the most complex issue; could it be that some impurities (such as fragments of valve components) have entered the outlet pipeline, causing knocking noises?
Add a flow restriction orifice plate? ? ? Reduce the flow rate to thereby decrease vibration?
Vibration in reciprocating compressors is truly a troublesome issue; generally, months or even longer after the compressor is put into operation, most of the effort is spent on securing the pipelines. I wonder how long LZ’s unit has been in use? 1. Focus on checking the vibration frequency to determine whether it matches the natural frequency of the compressor. If it doesn’t match, then there could be other reasons for the vibration, but this possibility is very low. 2. Inspect and reinforce the supports for the outlet pipelines. 3. If vibration is caused by significant changes in operating conditions (return to the original operating conditions; if the vibration decreases), it is best to carry out pipeline design calculations based on the new operating conditions.
What is the capacity of the compressor? If the capacity is high, the amount of vibration energy generated is also relatively large; in such cases, acoustic simulation calculations are usually carried out on the piping to determine the appropriate support and suspension arrangements for the pipes, thereby keeping the vibration amplitude within the limits specified by API standards. The areas where vibration is typically most severe are at the bends in the pipelines leading out of the buffer tanks. It’s important to check whether there are adequate support and suspension mechanisms in place. If the compressor’s capacity is low, then it’s necessary to examine the support and suspension arrangements for the pipes, and adjust them as needed to change the pipe’s frequency and prevent it from matching the frequency of airflow fluctuations
Check if there is liquid present; open the outlet return inlet valve
Address the vibration first, as prolonged vibration can lead to unexpected issues. Solution: Add support to the outlet pipeline. Note that soft supports should be used for the braces, such as wooden supports. Then quickly find the cause, which can be done in conjunction with the process team. Let’s see by adjusting some operating conditions.
Has the pipeline been inspected or modified? Since the exhaust gas from reciprocating compressors is pulsatory, it’s easy to cause resonance if the pipeline isn’t designed professionally! It’s best to seek advice from experts in pipeline design!
Solution Summary 1: Increase the diameter of the outlet pipeline. 2. Install a buffer tank on the outlet pipeline; it is preferable to make it as large as possible, provided that space, cost, and aesthetics allow it. 3. Minimize the number of 90° elbows as much as possible. 4. Increase the number and strength of pipeline supports. 5. Orifice plates can be installed at appropriate positions along the pipeline. The most important thing is to eliminate the pulsation of airflow, converting the intense pulsational kinetic energy into static pressure energy; this helps to reduce vibrations in the piping and cylinder bodies, thereby improving the efficiency and safety of the compressor system