Impact of Sudden Change in Feed Olefins Content on Furnace Safety

During start-up of an ethylene plant, as part of the start-up sequence, it is typical to route recycle ethane back to the furnaces for cracking. During one such start-up of a Chevron Phillips ethylene plant following an upset, recycle ethane was routed to the furnaces as per normal practice. Soon after, there was a significant high temperature excursion of different furnace components including radiant coil and quench exchangers. The paper will go through the details of the incident and the safety learnings from the incident investigation.