Process Area Event – [I See Now-15] The Power of Dust

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This post was last edited by zdl1966 on 2016-10-24 at 11:23. It was 18 years ago; a dust explosion occurred during material feeding. Di-2-ethylhexyl sebacate is produced using the gap method. Sebacic acid is in powder form and tends to generate dust easily; feeding it in is done by creating a vacuum, but this can lead to blockages inside the tower, as well as in the reflux pipes. Without the use of vacuum, the feeding environment is poor; especially in continuous production, the temperature inside the reactor is high, resulting in octanol vapor mist, which makes it impossible for operators to carry out their tasks. So the boss decided to keep the vacuum valve open at half capacity, which gave good results. However, there was one incident: when the last package of material was being fed in, fire suddenly erupted from the feeding port, burning a worker’s eyebrows and hair. Later, I analyzed the cause and found it to be a dust explosion. It is widely agreed that in high-temperature environments, when the concentration of the mixture of isooctanol vapor and sebacic acid dust falls within the explosive limit range, static electricity generated by friction against the packaging bags can lead to an explosion. Therefore, the feeding method was changed to vacuum suction, with the pipes inside the tank inserted below the liquid level, in order to reduce the dust generated by sebacic acid and lower the concentration of the dust mixture. At the same time, modify the operating procedures by adding a new clause: It is strictly prohibited to start the mixer when the tank is empty, in order to prevent sparks from being generated as a result of wear on the PTFE sleeve of the mixer base.