Explosion at the Hydrogenation Tower of a Refinery
the explosion occurred inside the lower hydrogenation tower of a hydrogen peroxide unit, damaging the distribution tray inside the tower. 4 were killed and 2 injured, the direct economic loss was 488.2 million yuan. The hydrogenation tower is part of the hydrogen peroxide plant. Since the catalyst efficiency in the fixed bed of the lower tower decreases, the company decided to replace the catalyst: January 14: the old catalysts was unload of the lower and middle towers; February 8: The middle tower was refilled, the upper and lower towers were not refilled; March 13: Feeding and start-up was initiated, but only partial flow of the fixed bed in the middle tower and an uneven distribution of working fluid were noted; March 16: The leader of the hydrogen peroxide plant replaced the nitrogen inlet pipeline of the middle tower with a pure hydrogen inlet pipeline, but the problems of partial flow of the fixed bed in the middle tower and uneven distribution of working fluid were not resolved; March 17: The technician of the new catalyst supplier suggested adding a few more sieve trays to the middle tower distribution tray; March 18: from 8:00 am to 9:00 am, the leaders agreed to measure the upper part of the lower tower in order to install the middle tower working fluid inlet facility. At 8:40, workshop director and other 5 employees went to the third-floor platform of the device to check the measurement situation. At 9:26, two employees went to the platform on the fifth floor. At 9:32, one employee entered the lower tower at the same time. At 9:47:40, an explosion occurred inside the lower tower. A total of 4 people died in the accident and 2 people were burned by flames.
Event Date
March 18, 2015
Record Quality Indicator
Region / Country
Event Initiating System
Classification of the Physical Effects
Nature of the Consequences
Cause Comments
The immediate cause was the hydrogen inlet line shut-off valve leakage: hydrogen gas leaked internally into the tower and mixed with the air entering from the upper manhole, creating an explosive atmosphere and igniting . A contributing cause was the fact that the personnel of the enterprise did not take effective isolation measures and entered the lower tower of the hydrogenation tower to work. Root cause was a lack of risk management, of effective maintenance procedures, of risk assessment, of preventive and mitigation measures. A possible ignition source was sparks from electrostatic frictions produced by the use of non-explosion-proof tools. Operators were not carrying explosion-proof steel socket spanners when accessed the tower.
Facility Information
Application Type
Application
Specific Application Supply Chain Stage
Components Involved
hydrogenation tower
Storage/Process Medium
Location Type
Location description
Industrial Area
Operational Condition
Currency
Lessons Learned
Lessons Learned
Equipment maintenance and management were not in place. Since the start, of the operations, the have been no operation review and regular maintenance. This, and the absence of proper risk assessment, explains the absence of effective preventive and mitigating measures during the operation of catalyst replacement.
Event Nature
Emergency Action
unknown
Detonation
No
Deflagration
No
High Pressure Explosion
No
High Voltage Explosion
No
Source Category
References
References
Case study
http://3g.k.sohu.com/t/n478449026
(accessed May 2023)