Flash fire in the air duct of the reformation furnace

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Accident Name: Flash explosion and fire in the air duct of the reforming heater
Time of Incident: 19:48 on March 25, 2002
Course of the Incident: On March 25, 2002, it was still the startup phase; the reforming process had not yet reached normal operation, and the gas system was extremely unstable. The workshop requested that the personnel on duty check the gas system every half hour instead of every two hours. Four o’clock shift (Fifth shift) 19 ； At 45, it was detected that a large amount of gas contained oil; immediate actions were taken to remove the oil. However, the amount of oil present was substantial, and this caused tank D-3212 to fill up quickly, resulting in oil and gas entering the furnace. At 19:48, an explosion occurred in duct H-3205. The personnel on duty promptly shut down the gas system to halt operations urgently. At 19:49, the fire department was dispatched to deal with the fire, and it was extinguished at 19:52. After that, the gas system continued to deoil for another 4 hours before the process was completed, and feeding was resumed on March 26. Analysis shows that the liquid carried by the gas is the condensate oil from the two dewaxing units. Cause analysis: 1. Errors were made in the design of the technical renovation process for the two dewaxing units, and inadequate oversight led to a large amount of oil being present in the gas. The operators failed to remove this oil in time, which was the main reason for condensed oil entering the furnace and causing an explosion in the heater’s air ducts. 2. The liquid removal port of the vapor separator tank D-3212 is small, and inadequate liquid removal is also one of the reasons. 3. Another reason is that the personnel on duty did not have a clear plan for dealing with the situation of large amounts of oil in the gas, and failed to cut off the source of this oil-contaminated gas in a timely manner. Precautionary measures: 1. The two-stage separation device should be promptly adjusted to eliminate the risk of gas containing liquid, thereby preventing large amounts of liquid from being present. 2. Technical renovation projects should be carefully reviewed at each stage to avoid mistakes in the renovation process. 3. Develop a plan for dealing with large amounts of gas accompanied by liquid, and conduct training sessions and drills. 4. Report technical modification D-3212: add a level indicator. 5. During maintenance, a gas dehydration port was added as an improvement.