First Name
Andy
Last Name
Piatt
Severity
Incident
Was Hydrogen Released?
Yes
Was There Ignition?
Yes
Incident Date
Jan 09, 2005
Setting
Equipment
  • Piping/Fittings/Valves
  • Piping
  • Heating Equipment
  • Heat Exchanger
Damage and Injuries
Probable Cause
When Incident Was Discovered
Lessons Learned

Based on the results of the company investigation and analysis of an amateur video, the company determined that the incident could have been caused by the failure of one of the following plant components:
· pipes leading to the reactor pressure gauges
· the recycled quench gas pipe at the bottom of the reactor
· the diathermic oil pipe (hot oil) entering or exiting the heat exchanger
· the heat exchanger flanged joints and connection lines.

The company determined that a release from the hot oil circuit could not have triggered the fire, based on the evidence from the pressure data in the circuit, which showed that the failure occurred 30 minutes after the fire started. The video confirms the pipe rupture 30 minutes after the fire began. For the same reason, a release from the hydrogen pipes is not considered likely, as the records demonstrate that the hydrogen pipe failed seven minutes after the fire began. When the heat exchanger flanged joints were dismantled, it was seen that the joint gaskets were not damaged. Thus, the company considers the failure of a pipe from the reactor pressure measurement gauges to be the most likely cause of the accident (although there is no conclusive evidence to identify the specific failure that caused the pipe to rupture). This assumption is supported by the following facts:
· This pipe is located in the area corresponding to the epicenter of the fire.
· The area corresponds to the area visually identified by the witnesses.
· The product release (hydrogen and fuel oil) from one of these pipes can cause a 6-meter long jet flame, as occurred.
· The product supposedly released would have had a high enough temperature and pressure to self-ignite or ignite against a plant hot spot (e.g., the hot oil circuit).
· The damages recorded were caused by overheating (flame exposition) and were not caused by overpressure or explosion. The pressure measurement records confirm no significant pressure changes at the beginning of the event.

The company decided to rebuild the hydrotreatment plant, in compliance with regulations, and to introduce the following process design changes:
· complete separation of the light fuel oil section and the heavy fuel oil section to avoid the possibility of "domino effects"
· lowering the maximum height of the heat exchanger installations from 25 meters to 15 meters to facilitate fire-extinguishing operations
· redesign of the piping system to minimize adjacencies
· relocation of the valves on the hydrogen quench line to enable depressurization
· reduction of the number of measurement gauges
· insertion of valves in a safe area for depressurizing the hot oil circuit.

Key:

  • = No Ignition
  • = Explosion
  • = Fire
Hydrogen Incident Summaries by Equipment and Primary Cause/Issue
Equipment / Cause Equipment Design or Selection Component Failure Operational Error Installation or Maintenance Inadequate Gas or Flame Detection Emergency Shutdown Response Other or Unknown
Hydrogen Gas Metal Cylinder or Regulator   3/31/2012
4/30/1995
2/6/2013
4/26/2010 12/31/1969     3/17/1999
11/1/2001
12/23/2003
Piping/Valves 4/4/2002
2/2/2008
5/11/1999
4/20/1987
11/4/1997
12/31/1969
8/19/1986
7/27/1991
12/19/2004
2/6/2008
10/3/2008
4/5/2006
5/1/2007
9/19/2007
10/31/1980
2/7/2009 1/24/1999
2/24/2006
6/8/1998
12/31/1969
2/7/2009

9/1/1992
10/31/1980

10/3/2008  
Tubing/Fittings/Hose   9/23/1999
8/2/2004
8/6/2008
9/19/2007
1/1/1982 9/30/2004
10/7/2005
  10/7/2005  
Compressor   10/5/2009
6/10/2007
8/21/2008
1/15/2019
    10/5/2009 8/21/2008  
Liquid Hydrogen Tank or Delivery Truck 4/27/1989 12/19/2004
1/19/2009
8/6/2004 12/31/1969   1/1/1974 12/17/2004
Pressure Relief Device 7/25/2013
5/4/2012
1/15/2002
1/08/2007
12/31/1969        
Instrument 1/15/2019 3/17/1999
12/31/1969
2/6/2013
    11/13/73    
Hydrogen Generation Equipment 7/27/1999     10/23/2001      
Vehicle or Lift Truck   7/21/2011         2/8/2011
12/9/2010
Fuel Dispenser   8/2/2004
5/1/2007
6/11/2007
9/19/2007
  2/24/2006
1/22/2009
     
Fuel Cell Stack            

5/3/2004
12/9/2010
2/8/2011

Hydrogen Cooled Generator       12/31/1969
2/7/2009
     
Other (floor drain, lab
anaerobic chamber,
heated glassware,
test chamber,
gaseous hydrogen
composite cylinder,
delivery truck)
  11/14/1994
7/21/2011
7/27/1999
6/28/2010
8/21/2008
12/31/1969
3/22/2018
    6/10/2019
  • = No Ignition
  • = Explosion
  • = Fire