Transfer Line Exchanger Analysis Case Study

Problem

A client purchased approximately fifty Transfer Line Exchangers (TLE) valued at $18MM. The equipment was designed to operate for over twenty years. Within twelve months after startup the equipment failed. This equipment is used in ethylene facilities to quench cracked gas exiting out of a furnace. The gas side process conditions were approximately 1650 °F and 1 bar. The shell side conditions were saturated water at 616 °F. Each failure caused approximately $1MM in expense and posed a safety hazard.

Solution

KHE developed detailed waterside computational fluid dynamics (CFD) models to investigate the cooling of the inlet tube sheet. CFD also was utilized to determine the aerodynamic conditions of the flow entering the exchanger. The heat transfer and stresses of the heat exchanger were determined by finite element methods. KHE’s work determined that the root cause was a low flow zone that caused superheating and failure. Our work was verified by the client and vendor of the equipment by experimental investigation. Scale models were built and was determined that KHE’s CFD and FEA work matched the experimental model. KHE utilized the same CFD and FEA methods to redesign the equipment.

Result

A major failure root cause was determined. The client saved several million dollars in lost production. The problem was solved by KHE on the first iteration of design and stands as a model in industry today.