Predicting gasket lifetime with Alfa Laval Performance Audit

This major petrochemicals company and long-standing Alfa Laval customer used 39 Alfa Laval plate heat exchangers for critical cooling duties at its plant. The heat exchangers operated for many years without requiring maintenance. However, production reliability is only as good as the quality and operating condition of equipment components.

Why an Alfa Laval Performance Audit?

Many factors affect the operating condition of heat exchangers. Process conditions and heat transfer media, for instance, may change. Opening the heat exchanger frequently also influences heat exchanger performance. These have a direct effect on the mechanical condition of the heat exchanger.

“Even if the gaskets are selected to meet design conditions, they can either last longer or require replacement earlier than expected depending on actual operating conditions,” notes Tyba. “Gasket rubber also ages, which affects the sealing force as well as the service life of the plate heat exchanger.”

“Conventional wisdom says, ‘If it’s not broken, don’t fix it’,” he continues. ”Alfa Laval heat exchangers had delivered solid performance for so long that the customer didn’t see a need to conduct maintenance.”

According to the data in the Alfa Laval database, Tyba noted that it was time to verify gasket condition in order to ensure the operational reliability of the heat exchanger.

The scope of work comprised internal and external inspection of the heat exchanger to determine the current condition of its:

• Channel plates, including detailed plate deformation analysis
• Gaskets, including a prediction of remaining lifetime
• Frame, including connection linings
• Bolts and bearing boxes
• Spare parts inventory

Long-term service for a long-time customer

Based on our experience and knowledge of material properties, Alfa Laval analyzed the data. The data clearly indicated that the gaskets were approaching the end of their service life, and that reconditioning of the plates was necessary. Alfa Laval provided the customer with a report including detailed findings with an explanation of the audit results as well as photographs showing the actual condition of the plates and gaskets. To secure production uptime, Alfa Laval recommended reconditioning these 39 plate heat exchangers operating at the plant. The customer agreed.

“Clearly the reliability of the entire plant was at stake if operations continued with the old gaskets,” he continues. “The risk of an unplanned shutdown was very high considering that each plate heat exchanger has 591 plates. That’s more than 23,000 plates that were at risk.”

With hard facts and the ability to predict gasket lifetime, Alfa Laval is working on a preventive maintenance plan to optimize plant performance.