| Case Name |
Eruption due to a runaway reaction from incorrect charging quantity in the preparation of acrylic resin adhesive |
| Pictograph |
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| Date |
October 30, 1991 |
| Place |
Kawagoe, Saitama, Japan |
| Location |
Paint factory |
| Overview |
In a batch reactor at an acrylic resin plant, as the charging quantity of a monomer and a solvent was incorrect due to misoperation of a computer, the reaction ran out of control, and there was a blowout accident. If an operation standard for the computer had been established, misoperation could have been avoided. Besides, if the charging quantity had been checked before the reaction, the error in the charging quantity could have been detected beforehand. In addition, if a HAZOP examination had been carried out at the process design stage or on starting operation, the potential hazard could have been noticed. |
| Incident |
There was a leakage at an acrylic resin plant that performed synthesis in a batch reaction. As the charging quantity of a monomer and a solvent was incorrect due to misoperation of a computer, the reaction ran out of control. A rupture disk (90 KPaG) in the pressure release piping operated, and the reactor contents were discharged into an outdoor receiver. However, some of the reactor contents blew out, destroying a Teflon gasket of a flange of a condenser. |
| Processing |
Manufacture |
| Individual Process |
Charge and feed |
| Process Flow |
Fig2.Unit process flow
|
| Substance |
Butyl acrylate, Fig3 |
| Ethyl acrylate, Fig4 |
| Acrylic resin |
| Type of Accident |
Leakage |
| Sequence |
Resin, an acrylic monomer, and a solvent (ethyl acetate, etc.) were respectively charged into reactors of an acrylic resin plant, and heating started with remote operation from the main control room. It was confirmed that the temperature had reached the set temperature, and the operator went to the site to confirm the condition of the reactor. Liquid leaking from the flange of the condenser was found. Soon after the abnormal reaction was informed to the other workers, smoke blew out of the reactor room. |
| Cause |
As the charging quantity of a monomer and a solvent was incorrect due to misoperation of a computer, the reaction ran out of control. |
| Response |
The fire brigade stood ready to fight the fire. |
| Countermeasures |
Establishment and execution of a computer operation standard manual. Confirmation of raw material compositions in reactors before the initiation of a reaction. |
| Knowledge Comment |
The error in the quantity of charging had a serious potential hazard of causing a runaway reaction. Effects of a charging quantity error must be evaluated beforehand, and then appropriate countermeasures should be taken for plants and operations. |
| Background |
In the process design of a reaction system or on starting operation, a study was not done on what would happen if the feeding quantity was incorrect. If a HAZOP examination had been done, a possibility of misdirection to instruments or their misoperation would have been indicated. Inadequate study of management seems to have been the true cause. About operation management, the system that allowed misoperation, an error in the charging quantity that might cause a runaway reaction, and started the reaction without checking the charging quantity-all were problems. |
| Incidental Discussion |
If an error in the quantity of charging can cause a problem, why were double or triple safety countermeasures not taken? In a batch reactor, installing a measuring drum is a major countermeasure. |
| Reason for Adding to DB |
Example of eruption in a batch reactor caused due to no care about incorrect charging quantity |
| Scenario |
| Primary Scenario
|
Poor Value Perception, Poor Safety Awareness, Insufficient Safety Measure, Organizational Problems, Inflexible Management Structure, Insufficient Check System, Carelessness, Insufficient Precaution, Insufficient Confirmtion, Planning and Design, Poor Planning, Measuring Mangement Planning, Regular Operation, Erroneous Operation, Miss Setting, Bad Event, Chemical Phenomenon, Abnormal Reaction, Secondary Damage, External Damage, Leakage, Loss to Organization, Economic Loss, Manetary Damage 16 million yen
|
|
| Sources |
Fire and Disaster Management Agency. Blowout caused by unusual reaction when manufacturing acrylic resin binding material. Accident cases of dangerous materials, 1991. pp.446-447.
National Dangerous Object Safety Association. Spouting during unusual reaction caused by incorrect charging quantities when manufacturing acrylic resin adhesive. 100 cases of accidents at dangerous facilities. -No.2- pp.119-120(1994)
Masahide Wakakura. Yoshiaki Iizuka. Runaway reaction. Accident prevention techniques. Research 25 on disasters. pp.301-311(1994)
|
| Physical Damage |
About 100 L of an intermediate of acrylic resin adhesive adhered to the area of 25 square meters in a building. Equipment was stained and a gasket of a condenser was damaged. About 33500 L of an intermediate of acrylic resin adhesive was destroyed. |
| Financial Cost |
¥ 16 million. (Fire and Disaster Management Agency) |
| Multimedia Files |
Fig3.Chemical formula
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Fig4.Chemical formula
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| Field |
Chemicals and Plants
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| Author |
DOBASHI, Ritsu (School of Engineering, The University of Tokyo)
TAMURA, Masamitsu (Center for Risk Management and Safety Sciences, Yokohama National University)
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