Quantitative Risk Assessment Study For Conversion Of Tank For Crude Storage In NRMT For Numaligarh Refinery Limited

Numaligarh Refinery Limited is 3 MMT capacity handling refinery which is situated in Golaghat district of Assam. Numaligarh Refinery Limited has planned for converting MS tank to Crude tank at NRMT.  Crude for the facility is received from Rail gantry and transferred to Refinery Crude tanks in NRL. Then the Crude is again transferred from Refinery crude tanks to Tanks at NRMT through pump.

The main objective of this study is to evaluate the potential risk levels for personnel due to accidental release of hazardous materials from loss of containment scenarios from the facilities and to demonstrate that individual risks are within the broadly acceptable regions. The Objectives of QRA are as follows:

  • Identification of the Hazards involved and possible failure scenarios for Conversion of Tank.
  • Calculation of physical effects of failure case scenarios which include Estimation of Jet Fire, Pool Fire heat radiation distances, Flammable gas dispersion distances, and overpressure explosion distances.
  • Failure Frequency evaluation.
  • Societal risk quantification and Potential Loss of Life estimation.
  • Perform a 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 such as Prevention, Detection, Control, Mitigation and Emergency response to ensure that all risks are in ALARP or in Acceptable region.

Risk is the general measure of potential economic loss or human injury in terms of the probability of the loss or injury occurring and magnitude of the loss or injury if it occurs. Risk thus comprises of two variables; magnitude of consequences and the probability of occurrence. The hazards and consideration arises from its tolerability to personnel, the facility and the environment. This involves the identification of initiating events, possible accident sequences and likelihood of occurrence and assessment of the consequences. The acceptability of the estimated risk must then be judged based upon criteria appropriate to the particular situation. This study tries to quantify the risks to rank them accordingly based on their severity and probability.