Assignment on Engineering error or accident reporting.Investigate and prepare a summary report on a major engineering project where considerable damage and loss of life has resulted from the way in...

ASSIGNMENT
ACCIDENT REPORTING / ENGINEERING ERROR
THE ESSO LONGFORD GAS PLANT ACCIDENT
    
Introduction of the Explosion
On 25 September 1998 (Friday), a vessel in First Gas Plant broke apart, and a considerable amount of hydrocarbons and gases released out resulting in fire and explosion [1]. Two workers were killed in the accident while eight others injured considerably. After the accident, the domestic and industrial supply of natural gas was ceased for the customers. The vessel in which the fracture occurred initially was a heat exchanger known as Demethaniser Reboiler, GP905. The vessel meant to heat the rich oil at the downside of the equipment known as Rich Oil Demethaniser. Near this vessel, there was another heat exchanger (GP922) which heated the rich oil flowing from Demethaniser to Rich Oil Fractionator. The GP922 had also incurred cracks in its flanges. The workers were trying to repair the leaks of GP922, when GP905 broke up and stopped functioning. In the observations it was found that the temperature of GP905 was very low about -48 C, just before the accident while the temperature in surrounding area was 100 C [2]. The main reason for decreased temperature was the absence of hot lean oil flow through the vessel. The pumps of Gas Plant-I stopped and could not restart. In absence of hot lean oil, the cold oil kept on flowing and its temperature dropped significantly. The fracture at the vessel released a lot of hydrocarbon vapors which ignited to take the form of fire and explosion which was so devastating that it could not be extinguished completely for the next 3 days. All the connected Gas plants were also ceased functioning and the supply of gas completely ceased and the restorstion could resume back on 14 October 1998 [1].
The Causes of Accident
When the pumps of Gas plant I stopped, the loss of lean oil circulation took place in the vessel [2]. The pumps failed to start again and remained nonfunctional until few hours. Consequently, many vessels experienced an immense shortage of hot lean oil which used to heat the vessels. The main function of those vessels was to exchange the heat of hot oil with the cold oil flowing through the absorbers. In absence of hot oil, the cold oil stream reduced the temperature of the vessel to a level of -48C. Due to extremely low temperature, the steel walls of vessel GP905 became brittle. When later the pumps resumed working, and the flow of hot oil poured in this vessel, the vessel developed cracks and fractures, and the oil exploded through the cracks in form of hydrocarbons and vapors. As the fire spread across the pipe racks, led to further explosions, and the operations of the pump failed. The restoration took lot of time until the complete fire was extinguished from all the vessels and the Gas Plant altogether. The Gas Plant I was completely isolated from the other 2 vessels GP2 and GP3.
Possibilities to avert the Accident
The accident would not have happened if necessary and adequate measures would have taken after tripping of pumps. When the employees could not start the pumps, it would have been estimated by the engineers that the cold oil stream will chill up the vessels in absence of hot oil and it would be dangerous for the plant as the vessels are not suited to function at such extremely low temperature. At that time necessary steps would have been taken to isolate the vessels to prevent the development of cold environment.
Inadequate training of Workers
The gas plant workers who were working there on Gas Plant- I on the day of the accident, were unaware of the potential hazards of blocked lean oil flow and did not take required steps to nullify them [2] [3]. The workers in charge of the operations and supervision also had no knowledge of the potential consequences of obstructed oil flow hence they took inappropriate steps. There was lack of proper training of both the operators and the supervisors. No operating procedures were there to guide them in handling the problem.
Interdependent structure of the Gas Plants
The connectivity between the vessels was interdependent to each other. The design of the condensate flash tank to protect it from reduced temperature was not...