| Case Name |
Rupture of the reactor due to a leak of cooling water during sulfonation reaction of nitrobenzene |
| Pictograph |
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| Date |
October 24, 1963 |
| Place |
Itabashi, Tokyo, Japan |
| Location |
Chemical factory |
| Overview |
Water leaked from the corroded part of the coil when cooling water was fed to the cooling coil in the reactor for sulfonate of nitrobenzene in a m-nitrobenzene sulfonic acid manufacturing plant. Water came in contact with fuming sulfuric acid in the reactor and the temperature of the reaction liquid rose. Therefore, a runaway reaction occurred, and the reactor burst by the rise of inner pressure. It is an accident that happened due to the incompleteness of the check of facilities and equipment for the prevention of reactor explosion, such as pressure release, etc. |
| Incident |
Water was fed in a cooling coil in a reactor of a m - nitrobenzene sulfonic acid manufacturing plant. Then, the temperature of the reactor rose suddenly, and the reactor burst, and 12 operators got injured. |
| Processing |
Manufacture |
| Individual Process |
Reaction |
| Process Flow |
Fig3.Unit process flow
|
| Chemical Reaction |
Sulfonation |
| Chemical Equation |
Fig2.Chemical reaction formula
|
| Substance |
m-nitrobenzenesulfonic acid, Fig4 |
| Fuming sulfuric acid, Fig5 |
| Nitrobenzene, Fig6 |
| Type of Accident |
Burst, leakage |
| Sequence |
The reactor in the m-nitrobenzene sulfonic acid manufacturing plant was charged with 1670 kg of 25 % fuming sulfuric acid . 600kg of nitrobenzene was added into the reactor, stirred, and the reaction started. Cooling water was fed in the cooling coil to keep reaction heat at 30 °C The temperature of the reaction liquid rose suddenly, a runaway reaction occurred, the internal pressure increased suddenly, and the reactor burst. 12 operators got injured. |
| Cause |
Since the bottom of the cooling coil for heat removal was corroded, the cooling water in the coil leaked out in the reactor. Water and sulfuric acid contacted, and the temperature rose suddenly by the heat of dilution. Therefore, a runaway reaction occurred, and the internal pressure of the reactor increased suddenly, and the reactor burst. |
| Countermeasures |
1. Inspection of equipment such as a reactor is strengthened.
2. The design pressure of the reactor should be improved so that the reactor should not burst even if a runaway reaction takes place. Or, the pressure relief device to suppress the rise of inner pressure below the design pressure is mounted.
3. Even if the cooling medium leaks, the equipment that doesn't abnormally generate heat should be made. Or, by restudy of the structure and reselection of the material, the equipment that has no-leakage structure or has the structure which does not allow direct contact should be installed. (the basic countermeasure) |
| Knowledge Comment |
1. The process to the runaway reaction is studied, and elimination of the defects related to runaway reaction is attempted.
2. Safety measures are taken so that a reactor etc. should not break and/or explode even if a runaway reaction occurs. |
| Background |
1. Due to inadequate inspection of the reactor, the corrosion of the cooling coil could not be found.
2. Safety equipment such as pressure relief facilities against a runaway reaction was insufficient.
3. There is a problem in the design of the reactor as heat is generated whenever leakage occurs. Instead of water, safe cooling medium, such as kerosene, should be adopted. Though it costs a great deal, it is worth consideration. Moreover, it is also possible to stick the cooling panel on the wall outside of the reactor, and make it the dual structure. Though it might have been difficult to try these methods at that time (1963), it is possible now. |
| Incidental Discussion |
The accident was caused due to reckless design of the facilities. Water leak may easily occur due to corrosion and cracks, etc. There was only such a poor countermeasure at the time of 1963. |
| Reason for Adding to DB |
Example of accident caused due to inadequate inspection of facilities and countermeasures for the abnormal reaction |
| Scenario |
| Primary Scenario
|
Poor Value Perception, Poor Safety Awareness, Inadequate Risk Recognition, Organizational Problems, Inflexible Management Structure, Insufficient Information Transfer, Sulfonation Reaction, Usage, Maintenance/Repair, Inadequate Inspection, Planning and Design, Poor Planning, Poor Design, Failure, Abrasion, Corrosion, Bad Event, Chemical Phenomenon, Abnormal Reaction, Failure, Fracture/Damage, Failure, Large-Scale Damage, Rapture, Bodily Harm, Injury, 12 person injured, Loss to Organization, Economic Loss, Factory Complete Damage
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| Sources |
Masamitsu Tamura, Masahide Wakakura, Explosion under sulfonation reaction of the nitrobenzene, Reaction danger. -Accident case and analysis -. pp.104-108(1995)
Tokyo Fire Dep., Fire Prevention Div., 6 hazardous object, Disaster case knowledge of the hazardous object business, pp.156-157(1972)
Ministry of Labor Industrial Safety and Health Department safe section, Explosion under sulfonation reaction of the nitrobenzene. Safe of the batch process. pp.64-65(1987)
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| Number of Injuries |
12 |
| Physical Damage |
A factory completely collapsed. |
| Multimedia Files |
Fig4.Chemical formula
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Fig5.Chemical formula
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Fig6.Chemical formula
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| Field |
Chemicals and Plants
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| Author |
OGAWA, Terushige (Graduate School of Environment and Information Sciences, Yokohama National University)
TAMURA, Masamitsu (Center for Risk Management and Safety Sciences, Yokohama National University)
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