Nelius J. Joubert, Sasol, South Africa and Trey W. Walters, Datacor, Inc.(formerly Applied Flow Technology)
Abstract:
This study examines the transient behavior of pump trips and non-return valve closures in a petrochemical plant’s cooling water system. The system consists of five pumps supplying 100 000 m³/h at 450 kPa, with hydraulically actuated non-return valves and surge towers. Water hammer simulations were conducted to evaluate valve closure rates, mechanical integrity and operational stability. Rapid valve closures prevent reverse rotation but increase valve stress, whereas slower closures risk re-energization complications and plant trips. A closure time of 6 – 12 seconds is recommended to mitigate risks. Findings provide insights into balancing several competing factors such as preventing pump damage, preventing valve damage, minimizing overcurrent trips, and ensuring reliable cooling system performance.
