(213c) Fired Heater Damage Following Outage Due to Management of Change Problems

During the restart of a fired heater following a unit outage, the heater experienced extensive tube damage from overheating. The heater tubes were damaged because the heater fired without gas flow through the tubes during the reduction step of the platformer catalyst regeneration process just prior to unit startup. Gas flow to the heater had stopped because the gas compressor had shut down as a result of low lube oil pressure. During the unit outage, the platformer compressor instrumentation was cut over to the new distributed control system (DCS). The operators were unaware that the compressor had shut down because the alarms for the newly installed compressor instrumentation were suppressed as part of the phased cutover of the DCS.

After noticing that the heater firing rate increased without a corresponding increase in the process temperature, the operators began investigating the reason for the heater malfunction and noticed that the heater and its tubes were overheated. A short time later, the operators discovered that the compressor had shut down. Limited instrumentation prevented a more rapid diagnosis of the problem. This incident resulted in significant equipment damage to the heater and an extended unit shutdown.

The underlying causes of the incident are related to pre-startup safety review, management of change, procedures, computer displays and alarms, and communications.