Flammable gases, accidents with

The final state of an accident sequence with a hydrogen release comprises the formation of a flammable gas mixture either inside H2 carrying components or inside the building or outside in the open atmosphere. 

The investigation of a serious event frequently shows that a similar accident had occurred before, but that one item in the chain of events was not in place. For example, at one facility, certain critical safety valves were known not be reliable. If they did not close properly, large quantities of flammable gas would vent to the atmosphere. This event had occurred a number of times over a period of years with no serious consequence. However, one particular release occurred during a lightning storm. The lightning lit off the gas the subsequent fire initiated a train of events that resulted in a serious explosion. 

Technical - Lighter - Other functions can be integrated at lower cost - Better noise dampening - Surface structuring - hunold painting (IMP) possible - Quality variations due to semifinished goods - Flammable with smoke gas formation - Splinters/tears open in accidents - Less absorption of energy... 

Sharing of past major incidents with other oil and gas industries provides useful input data for similar process industries in order to identify the most critical barriers and improve their safety processes. One poignant example highlights this matter. In 1998 there was an accident in the gas compression stage of a Middle East oil and gas plant which caused 7 dead as a result of fuel accumulation and vapor cloud explosion which was very similar to the Texas City Refinery disaster on March 23, 2005 in which a distillation tower was overfilled and an uncontrolled release of hydrocarbons led to a major explosion and fires. Fifteen people were killed and 180 were injured in the worst disaster in the United States in a decade. In both incidents, excess hydrocarbons were diverted into a pressure relief system that included a blowdown stack. In the Iranian case, it was equipped with a flare, but one which the operator didn t ignite in Texas City the blowdown stack was not equipped with a flare to burn off hydrocarbons as they were released. As a result, the flammable overflow from the tower entered the atmosphere. Ignition of the escaped hydrocarbons was enabled by startup of a nearby vehicle resulted in the explosion and subsequent fires (Hopkins, 2008). This example shows the repetitive patterns of accidents, and root causes of events all over the world in this sector. The lesson of this paper is that accidents in one country, where the scenarios are very similar, can and should serve as lessons to prevent the same scenario being actualized in other countries. 

The introduction of a permit-to-work procedure should be considered when the potential consequences of an accident are severe and when communication is required between different organisations. Examples of situations with severe potential consequences are installation and maintenance of high-voltage systems, systems that contain large quantities of toxic or flammable gas and mechanical systems where an accidental start may cause substantial harm. 

Ammonia, when released is a toxic gas with little flammability. It is imported by sea into the 14,(XX) tonnes capacity tank at Shell UK Oil where the refrigeration maintains the temperature below the boiling point of the gas (33° C). Three ways were identified whereby several hundred tonnes of liquid ammonia could be released into the river to vaporize and disperse. The worst accident would have an accompanying explosion or fire on an ammonia carrier berthed at the unloading jetty. Next in order of severity is a ship collision and spillage into the river near the unloading jetty. The consequences of a collision between ships occurring within the area but not near the jetty were also calculated. 

Sometimes two other incidents are attributed to LNG The first one - a construction accident on Staten Island in 1973 - was cited as a LNG accident because work was carried out inside an empty LNG tank. The second - an electrical seal failure on a LNG pump that failed in 1979 - caused an explosion because gas (not LNG) entered an enclosed building. This event gave rise to a thorough revision of the code for electrical seals used with all flammable fluids underpressure [10],... 

A hazardous potential was thought to exist in the AVR HTGR, Julich, with a hydrogen-carbon monoxide-helium-air mixture, which could evolve in a water ingress accident scenario with an estimated 8 % H2 + CO concentration resulting from the corrosive reaction between steam and hot fuel element graphite. Ignition experiments in a combustion chamber were conducted in 1971 to examine the lower combustibility limit in respective gas mixtures. The tests have shown that a mixture with 22 % H2 + CO was not flammable at temperatures up to 120 °C [54],... 

Accidents In the event of skin or eye contact with liquid oxygen, seek medical attention for cryogenic burns. Do not enter areas of high oxygen gas concentration, which can saturate clothing and increase its flammability. Ventilate area to evaporate and disperse oxygen. 

Of the two test carried out, only one produced ignition. The lack of ignition may be explained by "accidents" in concentration referred to in subsection V.B., the ignition source being in contact with a mixture that was, at the moment, non flammable. On the other hand, H is a gas that is appreciably more flammable than CHZ, and spontaneous ignition of the mixture formed in the course of leakage is much more probable. 

Figure 8.20 Icon of a myth. The Hindenburg disaster of 6th May, 1937 put an end to the airship as a means of transport, and it has also been a major public relations disaster for hydrogen, since this was the lifting gas used. The accident led to the widely held myth that hydrogen is a particularly dangerous substance. Although the accident was tragic for those involved, the number of casualties was 37, quite low for an aircraft crash. About 2/3 of those on board survived. Many of those who died were burnt by the diesel fuel for the propulsion system, and in any case the fire did not start with the hydrogen, but with the skin of the airship, which was made of a highly flammable compound (Bain and VanVorst, 1999).

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