QRA for GAIL SKPL Pipeline and Dispersion Module Analysis of GAIL Bangalore City Pipeline

GAIL (India) Ltd was incorporated as a Central Public Sector Undertaking (PSU) under the Ministry of Petroleum & Natural Gas (MoP&NG) in August 1984. The Dabhol – Bengaluru Natural Gas Pipeline was commissioned in February 2013 by GAIL.  It has been designed to carry a gas volume of 16 MMSCMD (Million Standard Cubic Mtrs per day).

In addition to the main trunk lines, the KKBMPL pipeline which starts from Kochi to Mangalore is also interconnected to DBPL at the Singasadra point via Krishnagiri. The Singasandra – Krishnagiri Natural Gas pipeline spans over a distance of 48.4 km. The SKPL Pipeline currently has 2 SV Stations and receiving terminals namely SV 27- Chandapura, SV 26- Attibele and RT- Singasandra respectively.

Gail (India) Limited has entrusted iFluids Engineering to carry out Quantitative Risk Assessment (QRA) study for the Gail 24” RT-Singasandra to Krishnagiri Pipeline and its Stations along with the Dispersion Module analysis of the entire 18” Bengaluru spur line (73 KM) starting from SV-22 to RT-Singasndra which includes 7 SV stations of KKBMPL.

QRA Study

The main objective of this study is to estimate the potential risk levels for personnel due to accidental release of hazardous materials from loss of containment scenarios from the facilities and to exhibit that individual risks are within the broadly acceptable regions.

The Objectives of QRA are as follows:

  • To Identify Hazards and Major Loss of Containment (LOC) events.
  • To Calculate physical effects of failure case scenarios which include Estimation of Jet Fire, Pool Fire heat radiation distances, Flammable gas dispersion distances, BLEVE and overpressure explosion distances.
  • Failure Frequency evaluation.
  • To quantify Societal risk and estimate Potential Loss of Life.
  • To Perform risk assessment to confirm that risk can be reduced consistent with the ALARP principle according to the UK HSE risk acceptance criteria.
  • Recommend risk reducing measures to ensure that all risks are in ALARP or Acceptable region.

Vent Dispersion Study

The Dispersion Study includes the following steps:

  • To estimate quantity of consignment release from the vents to atmosphere
  • To evaluate potential hazards and subsequent effects of fire, explosion, toxicity etc. whichever and wherever is applicable.
  • To identify hazards and how they could materialize.
  • To recommend suitable height for the open vents.

Dispersion modelling was conducted to evaluate the effect distances of the released consignment from vent scenarios and their impact on dispersion.