(120f) Induced Draft Fan Reliability Case Study

Induced draft fans are normally installed on top of the furnace and are critical equipment in the operation of Ethylene furnaces as they are susceptible to vibration related and other reliability issues.

This paper discusses a case study involving an ethylene furnace induced-draft (ID) fan that suffered reliability issues resulting in unplanned plant shutdowns leading to estimated $18 million in lost opportunities. We will explain some of the symptoms that the induced draft fan may have experienced that could have resulted in the unplanned furnace shutdown. Finally we will also describe the design changes that were made to the new ID fan using the design features of API-673 fan specification and improved the ethylene furnace overall reliability.