After 6 years operation the client was experiencing repeated fan blade failure on air coolers operating on their gas production platform located in the South China Sea. Blades experienced catastrophic failure resulting in damage to the lower tube rows of the air cooler bundles and causing repeated unscheduled shutdowns and loss of production. The platform has a total of 8 air coolers (36 fans & drives) with damage affecting 3 units.

Jord was engaged to undertake a comprehensive failure study to determine the cause of fan blade failures and to establish the action & modifications necessary to attain full reliability of the air coolers.

This study included: Full comprehensive review of the original design of the equipment, site condition assessment, drive alignment, fan set‐up & blade angle, maintenance & operation history Vibration analysis of drive bearings, motors and structure and detailed component inspection, Analysis of environmental conditions, history, prevailing wind direction and speeds; Air flow analysis including identification of structural obstructions and impact on air flow to the coolers Metallurgical and mechanical assessment of failed blade components.

Jord determined the repeated fan blade failure on specific air coolers was due to blade overload resulting from gusting cross winds impacting coolers exposed to prevailing seasonal winds along the outer NW side of the of the platform. Under these conditions, the fans experienced disruption to axial flow causing cyclic loading/unloading of the fixed blade shank each rotation, eventually resulting in fatigue cracking of the blade shank.

Jord prepared a plan which included design changes, more resilient fans, modifications to drive components and an integrated maintenance program to ensure the optimum reliability of the air coolers.

Client Benefits

Client attained a comprehensive and integrated solution that provided design modifications , change of fan design and maintenance package that provided increase life of the fans and the optimum reliability of the air coolers.