GD Compressor 8000 Hrs Maintenance - CCI Gujranwala

Maintenance Summary

The compressor was safely taken out of service and isolated using approved Electrical and Mechanical Lockout/Tagout (LOTO) procedures. Prior to the commencement of maintenance activities, the system was completely depressurized, and the cooling water and lubricating oil were fully drained to ensure safe working conditions.

The compressor was then completely dismantled for detailed inspection and overhaul. Valve covers, valve cages, suction and discharge valves, cylinder head covers, pistons, air packing boxes, and oil scraper boxes from all three stages were removed. All dismantled components were thoroughly cleaned and inspected for wear, damage, and overall serviceability.

Job Overview

Maintenance Activities Performed

During the maintenance, the 3rd stage cylinder and 3rd stage connecting rod were replaced with new components. In addition, the bottom-end bearing shells of all three stages were replaced as part of the scheduled overhaul.

All major wear components were renewed, including:

• Air packing rings
• Oil scraper rings
• Piston rings
• Rider rings
• Head cover gaskets for all three stages

As part of the suction valve overhaul, all twelve suction valve diaphragms and twelve suction valve cover seals were replaced. Following inspection, cleaning, and refurbishment, a total of twenty-four suction and discharge valves were reinstalled. All valve cages, valve covers, pistons, and cylinder head covers were then reassembled in accordance with OEM-recommended maintenance procedures and specified tightening requirements.

Additional Maintenance Activities

• Cleaning of the blowdown valve mufflers.
• Replacement of two 1-micron line filters installed downstream of the air dryer.
• Replacement of the panel pressure regulator valve.
• Cleaning of the pressure regulator inlet filter.

The compressor main motor rear cover was also removed for inspection. The motor rotor and stator were thoroughly cleaned, and all power and control terminal connections were inspected, tightened, and verified to ensure reliable electrical operation. Following completion of all maintenance activities, the compressor was reassembled, inspected, and prepared for commissioning and operational performance testing in accordance with OEM standards.

Overhaul and replacement of major wear components as part of the 8000-hour scheduled maintenance.

Testing & Commissioning

Following completion of all maintenance activities, the compressor was commissioned and initially operated under no-load conditions for approximately two hours to verify its mechanical integrity and overall operational performance.

During the commissioning period, all critical operating parameters were continuously monitored and verified, including:

• Lubricating oil pressure
• Cooling water flow and temperature
• Discharge air temperatures
• Motor current
• Compressor vibration
• Operating noise
• Air and oil leakage
• Loading and unloading sequence
• Operation of all safety and protection devices

The compressor started smoothly and operated without any abnormal vibration, unusual noise, excessive temperature rise, or leakage. All monitored parameters remained within the OEM-recommended operating limits throughout the test period, confirming satisfactory performance following completion of the maintenance work.

Safety System Verification

Following successful completion of the No Load test, the compressor was gradually transitioned to Full-Load operation. The compressor operated smoothly and maintained stable performance underload, with all critical operating parameters remaining within acceptable limits throughout the test period.

Recommendations

To ensure reliable operation, maximize equipment life, and minimize the risk of unplanned downtime, the following recommendations are strongly advised:

1. Filter and Oil Changes: Replace the main inlet air filter and lubricating oil after every 4,000 running hours using OEM-approved lubricant.
2. Routine Cleaning: Clean the main inlet air filter, cooling water line strainer, and cooling tower on a monthly basis.
3. Daily Inspections: Inspect the operation of all three stage auto drain valves daily and maintain/update the compressor daily log sheet during every operating shift.
4. Ventilation Improvements: Improve compressor room ventilation by installing additional exhaust fans to remove accumulated heat and maintain recommended ambient temperatures.
5. Cooling System Descaling: Descale the cooling tower and closed-loop cooling system every 4 months to restore cooling efficiency.
6. Adherence to Maintenance Intervals: Adhere strictly to the OEM-recommended 8,000-hour maintenance interval. Procurement of kits should commence well in advance to prevent overdue maintenance running hours.

Conclusion

The scheduled 8,000 running hours preventive maintenance was successfully completed, including the replacement of the 3rd stage cylinder and 3rd stage connecting rod, along with the overhaul and replacement of all designated wear components in accordance with OEM maintenance procedures.

Following completion of the maintenance, the compressor was commissioned and successfully tested under No Load, Half Load, and Full Load operating conditions. The unit demonstrated stable performance throughout the testing period, with all major operating parameters remaining within acceptable limits.