Fired Heaters Hazards of Operating with Fuel-Rich Firebox: Experience Shared and Lessons Learned

Fired Heaters Hazards of Operating With Fuel-Rich
Firebox:

Experience Shared and Lessons Learned

Edwar Jimenez Mogrezutt

The Bahrain Petroleum Company B.S.C. (Closed)

Kingdom of Bahrain

Abstract

Fired heaters are essential equipment in refineries, petrochemical plants
and other process industries. However, due to the nature of their operation,
they carry significant potential hazards. Fired heater related incidents can
cause serious injuries and loss of life, in addition to extensive damage to the
fired heater itself and the surrounding equipment, plus plant downtime and
consequent production losses. Hence ensuring safe operation of fired heaters is
vitally important and it ultimately contributes to the safe and reliable
operation of the process units.

Adequate devices and instrumented functions can be incorporated at the
engineering design stage of fired heaters, to improve overall inherent heater safety.
Useful tools such as hazard and operability studies (Hazops),
as well as layer of protection analyses (LOPA) are always available to
continuously assess, prevent and mitigate the risks associated with fired
heaters. Finally, comprehensive training and operating procedures are also part
of our line of defense. However, incidents can and still do happen for a
variety of reasons e.g. equipment malfunction, ineffective process monitoring
and not following procedures.  It is
mandatory that we learn from such incidents to understand and be aware of the
risks and what went wrong, and prevent them for happening again.

One area that is perhaps poorly understood and the hazards and risks of
which, less well appreciated, is the operation of a fired heater with a fuel-rich
atmosphere in the firebox. This operating condition is known by many names e.g.
“stalling”, “smothering” or, as we call it at Bapco,
“bogging” and it can be extremely dangerous. It can quickly escalate into an
explosion. In 2016 we experienced a bogging incident in a fired heater in crude
service, which was not recognised and misunderstood and could not be brought
under control. The only option was to manually trip the heater and then, after
detailed investigation and analysis, to restart the unit. In
this incident, correction actions were taken and a firebox explosion was prevented.

As a reactive response to this incident, Bapco launched an initiative to
develop a refinery-wide procedure for the operators to identify, prevent and
address a bogging i.e. fuel-rich condition, in any of our 45 fired heaters.
This is a challenging task given that the heaters have different
configurations, different burners and firing orientations, and range in age
from just 5 years to over 80 years.

In our presentation we share our experience, as well as the lessons
learned from the 2016 bogging incident on the crude unit heater and the steps
taken to prevent recurrence on this and other heaters. The presentation also addresses
the importance of reviewing, updating and developing high quality procedures
for the safe startup and operation of fired heaters to mitigate bogging and
other significant process safety events that have occurred in our industry. It
also highlights the vital role of Bapco’s process engineers and operators in
optimising heater operation, and the importance of developing and maintaining
in‑house knowledge, expertise and experience, especially when it comes to
maintaining and improving the safety, reliability, profitability and
environmental performance of fired heaters.

CCPS
Middle East Process Safety Conference (MEPSC), 2017

9-11
October 2017

Track: Lessons Learned & Best Practices

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