CASE STUDY

HAZard and OPerability Study (HAZOP) & Safety Integrity Level (SIL) Assessment Study

The focus on technological advancement in Refining Technology is now shifting towards up-gradation of the bottom of the barrel (Vacuum Resid). M/s IOCL has taken a strategic initiative to develop a process for upgrading vacuum resid (VR) to value-added products using a slurry type of reactor. The process, named “indResidH” has been established using an in-house (IOCL) developed catalyst. M/s IOCL and M/s L&T Hydrocarbon Engineering are jointly working for further development, scale-up, and subsequent demonstration of the indResidH technology.

The objective of this Demonstration Plant is to generate kinetic and hydrodynamic data relevant for scaling up the process to a commercial scale and also to be used for performance evaluation/demonstration of the hydro-processing catalyst system and reactor internals.

M/s L&T Hydrocarbon Engineering had engaged M/s iFluids Engineering’s Team of Process Safety experts to conduct Hazard and Operability (HAZOP) and Safety Integrity Level (SIL) study as part of this Project.

The objective of the HAZard OPerability study (HAZOP) was to

  • Identify the hazards inherent to the process
  • Identify the credible equipment/instrument failure likely to lead to accident scenario/hazards/operability issues.
  • Determine the cause(s) and consequence(s) of the process / operational deviation identified and mitigation measure (safeguard) available.
  • Wherever, the safeguard(s) found inadequate, recommendation(s) was proposed.

The Safety Instrumented Function (SIF) identified as a safeguard in the HAZOP, were taken into the Safety Integrity Level (SIL) Assessment to calculate SIL demand of the respective SIF.
The SIL assessment study is a method to establish a “fit-for-purpose” design of (instrumented) safety measures, which are able to mitigate process hazards with respect to safety, environmental impact, and economic loss. It comprises a semi-quantitative assessment of the process equipment and systems to be protected by the Safety Instrumented System (SIS).

The objective of the SIL study was to

  • Determine the SIL requirement for each SIF in order to meet the target mitigated event likelihood defined by M/s IOCL for the project.
  • Take into account the criticality of the SIF with respect to safeguarding personnel, the environment, and the facility itself

The methodology employed for the SIL determination had been a technique that uses a semi-quantitative method – Layer of Protection Analysis (LOPA) as defined in IEC 61511-3.