7/27/2019 Case Details _ Ignition of Rubber Remained in the Reactor During Cleaning at a Polybutadiene Manufacturing Plant

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 Scenario 

Case Name Ignition of rubber remained in the reactor during cleaning at a polybutadiene manufacturing plant

Pictograph

Date July 6, 1997

Place Ichihara, Chiba, Japan

Location Chemical factory

Overview

A poly butadiene plant was shut down, a polymerization reactor was opened to the air, and accumulated rubber

inside was removed. All of the rubber was not removed on the first day. It was decided to remove the remaining

rubber on the next day. The polymerization reactor was left open. Residual butadiene rubber generated heat by air

oxidization, and the rubber ignited spontaneously. It is necessary to simultaneously conduct oxygen-shortage

prevention during work and prevention of oxidation by air.

IncidentWhile a polybutadiene plant was shut down, a polymerization reactor was opened to the air, and it was cleaned.

Residual butadiene rubber that had accumulated inside ignited and a fire occurred.

Processing Manufacture

Individual Process Maintenance

Substance1,4-polybutadiene, Fig2

1,3-butadiene, Fig3

Type of Accident Fire

Sequence

The polymerization reactor at a polybutadiene plant was opened to the air, and removal work for residual rubber

inside started. This work was done about once every two months.

About 17:00 on July 6th, 1997. As all of the rubber was not removed completely in the first day, it was decided to

continue the removal work on the next day. The polymerization reactor was left open.

20:13. A fire occurred in the polymerization reactor. One fire engine and five fire fighters of a self fire fighting team

turned out.

20:27. The public fire department was notified. Nine fire engines and 24 fire fighters turned out.

20:43. The fire was extinguished by spraying water.

CauseAs accumulated residual polybutadiene generated heat by air oxidization, it ignited automatically.

In the past, accumulated rubber also caused ignition in a finishing process.

ResponseWater spraying with watering equipment.

Water spraying by self and public fire engines.

Countermeasures

Before stopping a polymerization reactor, adding an oxidation inhibitor.

Sprinkling water on removing rubber in the polymerization reactor.Reeducation by group training for accident prevention organization members.

Knowledge Comment

During work done by hand in an open vessel, because ventilation must be performed to prevent an oxygen-

shortage, air flows in. If there is a substance that generates heat by air oxidization, it will ignite spontaneously.

Although spontaneous ignition is not caused, as oxygen is consumed by the reaction, caution is needed about an

oxygen shortage.

It should be considered that residual substances in a reactor are intermediate semi-finished goods of a reaction or

impurities, not completed goods.

Spontaneous ignition takes place due to accumulation of heat. Therefore, if careful observation is performed,

prevention is not so difficult.

Background

The major cause was considered a mistake in safety management that overlooked the hazard of generating heat by

air oxidization under dry conditions. If a reactor is opened to the atmosphere, naturally air flows in. They did not

 

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.

Incidental Discussion

It is common sense in the butadiene field that high-concentration butadiene generates heat due to a

polymerization reaction if there is oxygen even in a very small quantity. Moreover, it is also common sense that the

polymerization substance generates heat in the presence of air. Many accidents related to butadiene have been

reported.

Reason for Adding to DBExample of fire caused due to opening of a vessel containing polymerized substances with spontaneous ignition

properties

Scenario Primary Scenario

Poor Value Perception, Poor Safety Awareness, Inadequate Safety Measure, Insufficient

Analysis or Research, Insufficient Prior Research, Study Not Grasping the Reaction Property,

Ignorance, Insufficient Knowledge, Insufficient Study, Planning and Design, Poor Planning, Poor

Overhaul Planning, Regular Movement, Careless Movement, No Showering for Safety, Bad

Event, Chemical Phenomenon, Abnormal Reaction, Secondary Damage, External Damage, Fire

Sources

Fire and Disaster Management Agency, Fire in reactor that was shut down and opened to air. Accident cases of 

dangerous material. 1997, pp.290-291.

High Pressure Gas Safety Inst. of Japan, High-pressure gas protection overview. 1998 edition, pp.76-77 (1998).

The Res. Inst. of Industrial Safety material. (closed).

Physical Damage Instrumentation and lighting facilities were destroyed by fire.

Financial Cost ¥ 3 mill ion. (Fire and Disaster Management Agency).

Multimedia FilesFig2.Chemical formula

Fig3.Chemical formula

Field Chemicals and Plants

AuthorITAGAKI, Haruhiko (Japan National Institute of Occupational Safety and Health)

TAMURA, Masamitsu (Center for Risk Management and Safety Sciences, Yokohama National University)

 Scenario