Flammable gas dispersion modelling on an offshore platform

Nur Syazni Mohd Suyut; Mohd Fadhil Majnis; Soraya Tamara Abdul Malik

doi:10.37934/progee.28.1.2842

Authors

Nur Syazni Mohd Suyut School of Chemical Engineering, College of Engineering, Universiti Teknologi Mara, Selangor, Malaysia
Mohd Fadhil Majnis School of Chemical Engineering, College of Engineering, Universiti Teknologi Mara, Selangor, Malaysia
Soraya Tamara Abdul Malik Process Safety, Petroliam Nasional Berhad (PETRONAS), Wilayah Persekutuan Kuala Lumpur, Malaysia

DOI:

https://doi.org/10.37934/progee.28.1.2842

Keywords:

Flammable gas, Dispersion modelling, Offshore platform, ALOHA, PHAST

Abstract

Flammable gas dispersed from the vent on an offshore platform can react in an explosive manner by the existence of air or pure oxygen at a certain concentration within its flammability limits. Due to unwanted accidents that might occur, resulting in loss of life and asset damage thus, flammable gas dispersion modelling was conducted to identify any recommendation or mitigation if required. Due to no risk assessment on the offshore platform to perceive the dispersion model based on various perspectives, multiple software was used in assessing recommendations and mitigation. Therefore, the flammable gas dispersion study carried out was to obtain dispersion modelling on the identified offshore platform's vent as an early solution to avoid the occurrence of risk scenario. The model of flammable gas dispersion has been developed by using two notable fire and explosion modelling software: Areal Locations of Hazardous Analysis (ALOHA) and Process Hazard Analysis Software Tool (PHAST). The meteorological conditions consist of wind speed, and atmospheric stability has been used as manipulated variables. Meanwhile, the vent designs (height, diameter, angle, pressure, temperature and flowrate of flammable gas release) and vent composition remain unchanged for all the selected weather conditions. The impairment assessment conducted showed the dispersion contour obtained through ALOHA and PHAST, no risk reduction and recommendations required as the plume dispersed at the highest cloud height, thus both the manned area or escape routes and muster area were not affected by the flammable gas released from the vent.

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