Amuay UCVE Event Aug 25 2012 (Saturday)around 1:10 AMDisclaimer: 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

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

Olefins are used to produce alkylate, amotor gasoline componentfor octane improvement

Olefins are stored in spherical tanks due to itshigh vapor pressure and low boiling point

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

Insiders reported that a olefins pump was leakinga pump seal failure perhaps?

In Amuay the strong prevailing trade winds blow there most of the year

These are a key design and operational factorWindOlefins pump leak not fixed, last for days

Randomly, during August and September, and before a downpourprevalent winds may slow, sometimes change direction, from its regular eastwarddirectionWindOlefins 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 WindOlefins pump leak not fixed, last for days

Olefins pump leak not fixed, last for daysAn operational decision seems to have been madeto maintain the equipment inoperation and keep the production on, relying on the wind to disperse the leaked vapors.

Those, in concentrations below 2% in weightrelative to air (LEL), are not flammableClick to continue

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 qualityWindLeak 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 nightWindLeak source

About Friday midnightThe wind slows. The now stillness does nothingto disperse the olefin vapors, which nowbegin to accumulate

In a tragic coincidence of events, the leak suddenly becomesmuch largerWindLeak source

Leak sourceWind

Leak sourceLow points/ pathLow points/ pathWind

Leak sourceWindLow points/ pathLow points/ path

Leak sourceWind

Leak sourceWind

Leak sourceWind

Leak sourceWind

Leak sourceWind

Leak sourceOne worker is on the pedestrian overpass, walks away, leaving the areaNational Guards livehere with their familiesWind

Leak sourceOne worker is on the pedestrian overpass, walks away, leaving the areaOne vehicle southbound approaches the vapor cloudLube oil plant team is still at workWind

Leak sourceOne worker is on the pedestrian overpass, walks away, leaving the areaOne vehicle southbound approaches the vapor cloudLube oil plant team is still at workWind

Leak source, now ignited, can be seen in the next photographsThe worker on the pedestrian overpass diesLikely the car ignites the cloud here. The explosion force pushes it towards the opposite curb as seen in the attached picFive lube oil plant workers perish while still at workMany people, houses are affected by the strong shockMany people, houses are affected by the strong shockWind

Olefins pump site

Olefins pump site

Overpass damage pic 2House damage pic 1Lube oil plant damages pic 5WindBusiness damage pic 3Lube oil plant damages pic 6Business damage pic 4

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The operational decisionto maintain the equipment inoperation 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

"I am living miracle.. it was not my time", said Edino Rafael Muoz 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 himLink: http://www.ultimasnoticias.com.ve/Noticias/Actualidad/Sucesos/Testimonio-en-Amuay---Estoy-vivo-de-milagro--no-me.aspx

Unconfined Vapor Cloud Explosion

UVCE

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.

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