(41be) Restoring Efficiency and Mitigating Environmental Impact in Ammonia Refrigeration Systems: A Case Study on Condenser Blockage and Maintenance Solutions

Fatimafert is an Ammonia – Urea complex located near Lahore, Pakistan which is operation since 1971. At Fatimafert, operational and safety challenges emerged due to the reduced efficiency of a refrigeration ammonia condenser associated with the refrigerant ammonia vapours compressor. The condenser inefficiency led to the release of ammonia into the atmosphere through purge openings, causing environmental concerns as the purged ammonia was diluted with water and drained into evaporation ponds, causing personal safety concerns. This also limited the ammonia inventory as purged ammonia could not be recovered in the Anhydrous Ammonia storage tank.

The proposed solution involved, pre-evaluation of multiple features during normal plant operation at 117% load capacity, like suitable time slot in which ambient and Cooling water temperature were observed minimum, stoppage of ammonia tankers filling that also contributes additional vapors load in to the system and halting the refrigerant ammonia compressor. Inspection revealed significant blockage in the condenser's shell passes and end cover, restricting cooling water flow. Hydrojetting was employed to clean the tube bundle, with four excessively blocked tubes plugged after cleaning attempts were unsuccessful. Following maintenance, the condenser was returned to service, achieving improved performance metrics—reducing outlet temperature from 47°C to 42°C and compressor discharge pressure from 18 kg/cm² to 16.5 kg/cm². Consequently, no purges were required, mitigating safety risks, and full ammonia recovery was resumed, thereby improving both operational and environmental outcomes.

This episode of ammonia vapor release in to plant operating area was taken as incident and investigated by multi-disciplinary team with valuable recommendations for permanent eradication of root cause.