The three-stage pressure of the reciprocating compressor is high; it’s not just a simple case of high pressure – I need help, urgently! !
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This post was last edited by yuchenchf on 2017-7-26 at 17:02. The compressors we use are Yuanda 4M32-142/0.1-26.5 models; the gas being compressed is CO from the PSA unit, and this gas contains a small amount of adsorbent powder. Recently, high pressure in the third stage caused the safety valve to activate (the normal operating pressure is around 1.26 MPa, while the current pressure at startup is 1.56 MPa). The first time we checked the fourth-stage exhaust valve and found no obvious cause; the pressure remained high even after it was opened. During the second inspection, the third-stage intake and exhaust valves along with their support rings and piston rings, as well as the fourth-stage intake and exhaust valves together with their support rings and piston rings, were checked. It was found that there was a seizing issue in the fourth stage; new piston rings and support rings were installed. New support rings and piston rings were also put in place for the third stage. Even after this, the pressure in the third row remained high, and the pressure in the second row increased as well. During the third inspection of the secondary intake and exhaust valves, as well as the secondary support rings and piston rings, it was found that there was a jamming issue in the secondary components; therefore, the secondary support rings and piston rings were replaced. When checking the air valves, all of them were replaced with new valve discs and springs; yet when they are turned on now, the pressure at stage 2 is still too high, and the pressure at stage 3 is extremely high. Experts who know the reason can contact me.
The powder must be the culprit; it’s easy for powder to get into the gaps of the valve seats and piston rings, which can cause leaks in the valves as well as problems with the retaining rings! During operation, check the external temperature of the valve chamber and compare it to determine whether there is a problem with the gas valve
The design pressures are all in MPa, while the pressures for the next two primary inlet and outlet stages are in kPa
The powder issue has been around for some time now; in the past, after it was properly handled and activated, the pressure in the three stages wouldn’t exceed the limit. This problem only started appearing recently, and the temperature of the air valves isn’t high either
I have encountered this situation before; back then it was due to high resistance in the inter-stage cooler tubes. This can be determined by using the parameters of third-stage discharge and fourth-stage intake to see whether the inter-stage pressure drop is within the normal range. The data you provided is too basic; at least the suction and exhaust pressures and temperatures for each stage are needed in order to make an assessment. Check whether there are any suction valves in stage 4 whose temperatures are abnormally high, as leaks in the valves of stage 4 can also cause high exhaust pressure in stage 3
It’s a level-4 valve; the valve disc spring has been inspected and replaced. Since it has been in operation for a short time, the temperatures at each stage have not yet risen, and the system shuts down due to overpressure in the third stage.
What do you mean by high resistance in the inter-machine cooling pipes?
Third-level exhaust means fourth-level intake
Between stages – when going from stage 3 to stage 4 – aren’t there inter-stage coolers and inter-stage pipelines? Are there no gas-liquid separation tanks or anything of the kind?
You are referring to the situation with no pressure drop, but the key question is: isn’t there any pipe resistance from the third-stage exhaust circuit to the fourth-stage intake? Inter-stage coolers, gas-liquid separators, various elbows, and so on all cause pressure drops
As mentioned on the 5th floor, check whether there is any blockage in the pipes and coolers between stage 3 and stage 4, which could result in a reduced flow area and overpressure at stage 3. Generally, high outlet pressure at the third stage is caused by problems in the lower stage. If there are problems with the third-stage piston rings, valves, etc., it will only result in a low pressure at the third-stage outlet and a high pressure at the second-stage outlet. Therefore, the items to be checked are as follows: 1. For the four-stage piston core puller, check the piston, piston rings, and support rings ； 2. Check the inlet and outlet valves at level 4 ； 3. Check for any blockages in the pipes, valves, and coolers between levels 3 and 4. I hope this can help you!