Abstract:
The Marsden Point Oil Refinery is owned and operated by Refining NZ and supplies 80% of New Zealand's oil product demand. This project investigates the cause of leakage of shell and tube heat exchangers located at the Marsden Point Oil Refinery, with the aim of developing recommendations that will prevent future leakage. To achieve this, a nonlinear finite element analysis has been used to determine the effect which temperature gradients within the tube-sheet have on the sealing performance of the flange joint. In addition, the bolt pre-stress required to seal the flange joint was determined. The analytical results have been used to provide recommendations that will prevent further leakage. It is concluded that a bolt pre-stress of 30% of the ambient temperature bolt yield stress should be applied to the heat exchanger flange joints. The analytical results showed that the application of bolt pre-stress in excess of this value risked causing damage to the flange joint that could lead to sealing problems.