Case Ditails

Scenario
Case Name Leakage and fire of naphtha caused due to overlooking of an open drain valve at an ethylene plant
Pictograph
Date May 16, 1989
Place Takaishi, Osaka, Japan
Location Chemical factory
Overview On May 16th, 1989, leaked naphtha ignited and started a fire around a cracking furnace at an olefin manufacturing plant in Osaka. Of 16 cracking furnaces, No.3 furnace was to be decoked. After stopping the supply of naphtha, the naphtha piping was steam-purged, and then steam-purging of ethane piping started. A fire started around the drain valve of the piping.
Incident The piping was purged for decoking a cracking furnace. The drain valve had been open and naphtha leaked from the piping. The naphtha ignited and a fire started.
Processing Manufacture
Individual Process Maintenance
Process Flow Fig2.Unit process flow
Substance Naphtha
Type of Accident Leakage, fire
Sequence Out of 16 cracking furnaces, No.3 furnace was to be decoked. After stopping the supply of naphtha, supply piping was steam-purged. Soon after steam-purging of ethane piping, a fire started around a drain valve.
Decoking: Removal of hard carbonized compounds adhering to the inside wall of a furnace tube. At an ethylene plant, this is usually done with air and steam.
Cause A drain valve of ethane piping had been left open after previously decoking the furnace. Naphtha remaining at a joint of ethane and naphtha lines back-flowed via the ethane line into the atmosphere, and was ignited by a flame in the furnace. The accident resulted from human error at the previous operation and line-up mistakes at the beginning of the operation.
Response An emergency shutdown of the plant.
Countermeasures 1. Removing unnecessary drain valves.
2. Thorough confirmation of valve operations.
3. Re-education on site management.
Knowledge Comment Decoking lines are usually used after long interval, so inappropriate operations may not directly lead to immediate trouble. Line-up operation at reuse after decoking should be done carefully.
Background 1. The drain valve had been left open since the previous decoking. This was a serious mistake in repair and operation management. A drain valve should be closed and capped or equipped with a blind flange when it is not in use to prevent leakage. It was also a serious mistake not to cap the drain valve.
2. The shape of the joint of an ethane line and a naphtha line might have been inappropriate.
Incidental Discussion For piping that joins two liquids, and that requires purging or draining, the drain valve should be downstream of the junction and installed as close as possible to the junction.
Reason for Adding to DB Example of fire caused due to overlooking of small matters of the field management
Scenario
Primary Scenario Carelessness, Insufficient Precaution, As Usual, Organizational Problems, Poor Management, Slackness of Management, Planning and Design, Poor Planning, Inadequate Design, Regular Movement, Wrong Movement, No Action, Secondary Damage, External Damage, Leakage/Fire, Bodily Harm, Injury, 1person injured
Sources Fire and Disaster Management Agency. Naphtha leakage and fire near olefin manufacturing cracking furnace. Accident cases of dangerous materials. pp.314-315
High Pressure Gas Safety Inst. of Japan. High-pressure gas protection overview. pp.153, 164-165(1990).
High Pressure Gas Safety Inst. of Japan. Ethylene manufacturing plant. Raw material naphtha leakage and ignition. Accident Examples of Petroleum Refinery and Petrochemical units. pp.113-116(1995)
Number of Injuries 1
Physical Damage No.3 cracking furnace, ethane piping, insulation and vaives were damaged. Electricity and instrument cables were partially destroyed by fire. About 50 L of naphtha was lost.
Financial Cost ¥2 million (Accident cases of dangerous materials)
Field Chemicals and Plants
Author YOSHINAGA, Jun (Graduate School of New Frontier Sciences, The University of Tokyo)
TAMURA, Masamitsu (Center for Risk Management and Safety Sciences, Yokohama National University)
Scenario