Abstract:

The propylene refrigeration system of the 460 kt/a ethylene plant at PetroChina Lanzhou Petrochemical Company had problems of long pipeline, many branches, nested loop and complex pipe routing due to its scattered refrigerant users. During the startup and shutdown of the plant, the purge and replacement of this section was difficult, and dead ends were easily left to cause potential safety hazards. Through optimization, three measures including installing recovery pump to recover the materials in system, positive purging and reverse purging were taken to ensure that the purge and replacement of the system can be completed in 2 to 3 days.

Key words: propylene refrigeration；purge and replacement, optimization