Hydrogen Compressor Explosion and Fire at a Refinery
An explosion and fire occurred at a reciprocating recycle hydrogen compressor during commissioning of a new Diesel hydrotreatement Unit. It happened during the reactor pre-sulphidisation step, when the recycle gas contained 9000 ppm of H2S (hydrogen sulfide) and the pressure was at 940 psig (65 bar). The failure of retaining bolts on head-end suction valve unloader of recycle cylinder on compressor allowed release of process gas. Investigations revealed that the bolts failed due to material inappropriate to prevent sulfide stress cracking) and inadequate design for the service. The manufacturer did not comply with the company's practice for reciprocating compressors in H2S applications.Estimated at $100,000 (1993). Damage to compressor shelter, instrumentation. Estimated 250 man hours spent on investigation.
Event Date
June 1, 1993
Record Quality Indicator
Region / Country
Event Initiating System
Classification of the Physical Effects
Nature of the Consequences
Cause Comments
The immediate cause was the failure of valve bolts on the hydrogen compressor which recycles the H2S-containing hydrogen coming from the hydrotreater. Contributing causes were an inadequate design, the choice of incorrect material and stress corrosion cracking
Facility Information
Application Type
Application
Specific Application Supply Chain Stage
Components Involved
hydrogen recycling compressor, bolts
Storage/Process Medium
Actual Pressure
65
Location Type
Location description
Industrial Area
Pre-event Summary
A Diesel Hydrotreater Unit removes impurities like sulfur and nitrogen from diesel, in the presence of a catalyst and hydrogen.
Lessons Learned
Lessons Learned
The ICHEME database (see reference) lists the following lesson learned:(1)Standards are essential to the safety of any process plant project. These standards apply to design control, purchasing, construction, and inspection and testing of purchased equipment. (2)Each group involved in a project, whether contractors, suppliers, designers, procurement, manufacture, construction, etc. plays a key role in assuring the equipment's fitness for use. (3)All possible process conditions must be detailed in the specification for the purchase of equipment. (4)HAZOP studies must include all deviations from the design operating conditions such as shutdown, start-up, maintenance, and other activities such as the pre-sulphiding process to check the adequacy of the design.
Event Nature
Emergency Action
Unknown
Release Type
Release Substance
Hydrogen Release Concentration (%)
99.00
Release Pressure (bar)
65.00
Hole Shape
Ignition Source
Detonation
No
Deflagration
No
High Pressure Explosion
No
High Voltage Explosion
No
Flame Type
Source Category
References
References
Event description extracted from the UK database ICHEME in PDF
ICHEME database is no longer available for purchase, but data can be download as PDF for free.
https://www.icheme.org/media/7178/activity-operationalactivities-detail…
(accessed November 2020)