Design, Installation, Operation and Maintenance of Transfer Line Exchanger Feedwater Systems

Ethylene transfer line exchangers, TLE’s, play an essential role in the process of producing ethylene.  It quenches the effluent gas coming from the radiant coils of the ethylene cracking heaters by transferring the heat to the water / steam side of the TLE.  High temperature steam is generated to pressures around 1800 psig that is used in downstream equipment and for process steam.   They operate as and require the same care as high temperature, high heat flux and high pressure boilers.

This paper addresses the importance of proper design, installation, maintenance, and pre-operation (commissioning) steps of the TLE Natural Circulation System to ensure the safe, reliable and long term operation of the equipment.  Following a short review of the TLE system, the paper will address measures to be taken before operation, during start-up, and during operation, and look at exceptional events that can spell doom to these highly critical pieces of equipment.