Gas explosions

Companies which handle, or are exposed to, hydrocarbons or other combustible gases or materials should systematically identify hazards related to possible releases to the atmosphere of these materials. The results of the identification process should be used both to evaluate the consequences of hazardous events and to determine appropriate risk reduction. Risk reduction measures should focus on:

  • preventing incidents (i.e. reducing the probability of occurrence)
  • controlling incidents (i.e. limit the extent and duration of a hazardous event)
  • mitigating the effects (i.e. reducing the consequences)

This is in accordance with e.g. ISO 13702 "Petroleum and natural gas industries - Control and mitigation of fires and explosions on offshore production installations - Requirements and guidelines".
Due to the geometrical complexity of many industrial plants offshore and onshore, gas explosions are complex events that may be accurately evaluated only by performing detailed CFD analyses, e.g. using FLACS. An identification of hazards related to gas explosions should therefore be based on the application of such tools. The figure below illustrates some of the capabilities of FLACS.
 


Several types of analyses can be performed, depending on the circumstances. Examples of these are listed below:

Two major requirements must be satisfied in such analyses:

  • Plant geometries must be represented in sufficient detail, containing all piping down to 2-3 cm diameter
  • In explosion analyses cloud sizes must be realistic, i.e. they should be based on dispersion analyses

If these requirements are not adhered to, the analyses may produce results which are wrong by an order of magnitude! The technical expertise of GexCon personnel would ensure that this is avoided.



The figure above shows flame development and spatial overpressure distribution in an explosion simulation using FLACS. Note the uneven pressure distribution, which is typical of complex geometries and often overlooked when simple predictive tools are applied.



Contact
Ronan Abiven
Phone no: +47 415 04 229
Email: ronan(at)gexcon.com