1. Amuay UCVE Event Aug 25 2012 (Saturday) around 1:10 AM
Disclaimer: RMG has developed the following material based on detailed analysis of information freely available on the net, our data bases, and from our industry contacts. We believe that an accurate event simulation and fact sheet has been developed, describing to the best of our knowledge the facts and consequences without warranties or judgments of any kind

2. In Amuay olefins are produced in
the cat cracking and in the coking operations

3. Olefins are used to produce alkylate, a motor gasoline component
for octane improvement

4. Olefins are stored in spherical tanks due to its
high vapor pressure and low boiling point

5. If this compound is released to the atmosphere,
a vapor cloud will form
This cloud mass will be about
50% heavier than air
Once released, it will flow in the ground
like a “river of fog”

6. Insiders reported that a olefins pump was leaking…a pump
seal failure perhaps?

7. Olefins pump leak not fixed, last for days
Wind
Olefins pump leak not fixed, last for days
In Amuay the strong prevailing
trade winds
blow there most of the year
These are a key design
and operational factor

8. Olefins pump leak not fixed, last for days
Wind
Olefins pump leak not fixed, last for days
Randomly, during August and September,
and before a downpour
prevalent winds may slow, sometimes
change direction,
from its regular eastward
direction

9. Olefins pump leak not fixed, last for days
Wind
Olefins pump leak not fixed, last for days
In the preceding days, atmospheric conditions
caused showers in the area,
the wind to erratically slow and
change direction

10. An operational decision seems to have been made
Olefins pump leak not fixed, last for days
An operational decision seems to have been made
to maintain the equipment in
operation and keep the production on,
relying on the wind
to disperse the leaked vapors.
Those, in concentrations below 2% in weight
relative to air (LEL), are not flammable
Click to continue

11. The day before leaking vapor had reached the facility perimeter
Wind
The day before leaking vapor had reached the facility perimeter
Amounts exceeding the allowable LEL (explosivity) were detected in the environment
On Friday, a neighboring lube oil manufacturing plant had to be evacuated due to poor air quality
Leak source

12. Weather situation seems to improve later on the day.
Wind
Leak source
Weather situation seems to improve later on the day.
A team of workers at the Lube oil manufacturing plant return, and tries to catch up with production on Friday late night

13. The now stillness does nothing to disperse
Wind
About Friday midnight
The wind slows.
The now stillness does nothing
to disperse
the olefin vapors, which now
begin to accumulate
In a tragic coincidence of events,
the leak suddenly becomes
much larger
Leak source

14. Wind
Leak source

15. Wind
Low points/ path
Leak source
Low points/ path

16. Wind
Low points/ path
Leak source
Low points/ path

17. Wind
Leak source

18. Wind
Leak source

19. Wind
Leak source

20. Wind
Leak source

21. Wind
Leak source

22. here with their families
Wind
National Guards live
here with their families
Leak source
One worker is on the pedestrian overpass, walks away, leaving the area

23. One vehicle southbound approaches the vapor cloud
Wind
One vehicle southbound approaches the vapor cloud
Leak source
One worker is on the pedestrian overpass, walks away, leaving the area
Lube oil plant team is still at work

24. One vehicle southbound approaches the vapor cloud
Wind
One vehicle southbound approaches the vapor cloud
Leak source
One worker is on the pedestrian overpass, walks away, leaving the area
Lube oil plant team is still at work

25. Leak source, now ignited, can be seen in the next photographs
Wind
Likely the car ignites the cloud here. The explosion force pushes it towards the opposite curb as seen in the attached pic
Leak source, now ignited, can be seen in the next photographs
The worker on the pedestrian overpass dies
Many people, houses are affected by the strong shock
Five lube oil plant workers perish while still at work
Many people, houses are affected by the strong shock

26. Olefins pump site

27. Olefins pump site

29. Wind House damage pic 1 Business damage pic 3 Overpass damage pic 2
Lube oil plant damages pic 5
Lube oil plant damages pic 6

30. 1

31. 2

32. 3

33. 4

34. 5

35. 6

36. The operational decision to maintain the equipment in
operation and depend on the wind to
to disperse the leaked vapors
was a tragically poor one
Fifty one lives lost so far
and many more badly burned…

37. "I am living miracle.. it was not my time", said Edino Rafael Muñoz Lambertino (35), a man of Libertad de Barinas, survivor of the blast, who was held imprisoned that night in the 44 National Guard depot located next to the Amuay Refinery. After being arrested on allegedly “soliciting” charges, he was to be released next day. “Why were you not sleeping then?... He was talking with the national guards. "We were then telling tales and the next day they were dead". He said that about 1 am on Saturday, they began to leave the facility since “the smoke was thick”. "Let's go there, need to make several ‘rounds’, the guards told us." Edino was led to the first jeep with 7 guards. The jeep stutter half way, and when they tried restarting the vehicle, there was an explosion. "It seems that it had lifted". "My mind was blank, like a dream, a nightmare". Edino jump the car and ran down the street until a corner where stop to rest. “When I look over there it came as a wave of fire, I laid down and prayed." "It went over and then returned again." After that flash, Edino looked back at the jeep: it was burning with all its passengers as well as another vehicle with military guards and a lady with a 5-month-old girl. "All died. I saw them the next day in the newspaper“. “It is strange that they stay put and did not run away." Scared, Edino resumed his escape and met a family who were evacuating. "Lord, help me that I can barely walk", yelled Edino to them, who then took him to the hospital. "I had glass fragments in my skin.“
On Saturday night, Edino had asked the guards why the strong smell of gas. "The guards said that these are valves that open at times and that it was “normal." "That's to “regulate” the tanks". But the atypical event of that day was that the gas began spreading across the street "as fog", according to him…
Link:

38. Unconfined Vapor Cloud Explosion
UVCE

39. The results seen in the prior pictures suggest a gas phase explosion event, which generated a large overpressure without the presence of confining walls.
This is referred to as Unconfined Vapor Cloud Explosion (UVCE).
When a flame travels through the unconfined gas cloud with high velocity, the gas/air mixture ahead of the flame is unable to move away quickly enough to allow free expansion of the combustion products formed by the flame. As a result pressure wave is formed ahead of the flame front with the destructive forces seen. Edino was a lucky witness to this.
The presence of obstacles (called congestion, observed where buildings may be in the path) within the flow field of the gas cloud produces turbulence which enhances the burning velocity, accelerates the production of combustion products and increases the flame speed. The higher the velocity of the flame, the higher the pressure generated ahead of it. If very high flame speeds are produced, a Transition from Deflagration to Detonation (DDT) can occur.
A detonation involves a very high pressure shock wave that further auto-ignites the gas/air mixture. The combustion of this mixture then provides the energy to sustain the shock wave, which may extend further than the vapor cloud. As a result, a detonation is self-sustaining as long as the concentration of gas is within certain limits. This can be observed in the effects caused on the mostly brick and concrete buildings, which even outside of the cloud, can be seen badly damaged, on support of our modeling of the vapor cloud boundaries.

40. Shock Wave Propagation Path
Update: More detailed aerial pictures, later available, tend to confirm the modeling results. From these, it can be observed a clear delineation resulting from high temperature gradients (as seen in burned vegetation) which results to be different from the shock wave front effects, which is mostly observed by the affected structures and how these are geographically distributed. A more detailed simulation of dynamic type can be derived from these results.
Shock Wave Propagation Path

41. RMG