Quantitative Risk Assessment for Vapour Recovery Unit and Effluent Treatment Plant of HPCL, Secunderabad Terminal

Hindustan Petroleum Corporation Limited has planned to set up Vapour Recovery Unit at Secunderabad Terminal. The unit consists of Knock-out drum, Absorber vessel, Adsorber vessels, Vacuum pumps, Return absorbent pumps, Blower and Nitrogen cylinder. As the vapour pressure of Motor spirit is high, they may flash and produce vapours during loading at TT Gantry.

Vapours collected from loading arms at TT/TW Gantry will flow through pipeline header to battery limit at VRU. Vapours received at battery limit will pass through a Knock out Drum (KOD) to remove liquid droplets. The incoming vapours will be filtered through Basket filter prior to the entry to Activated Carbon Adsorber (ACAD). The two adsorbers (Working/Stand-by) will be filled with activated carbon to adsorb hydrocarbons from vapours. Once the hydrocarbon level in the activated carbon reaches saturation, one vessel will be taken for regeneration and the other for operation. Suction blowers (Working/Stand-by) installed at the upstream of activated carbon bed maintain flow to VRU through headers. Nitrogen may be purged through the bed to transfer maximum amount of hydrocarbons to absorption column. The hydrocarbon – rich vapours pass into absorber and bulk of hydrocarbons get absorbed in a counter flow of Motor spirit. . The enriched Motor spirit from absorber shall be stored in above ground storage tanks / sent to common suction header line of MS TLF pumps to TLF gantry or sent to underground tank to TLF pumps suction header.

Effluent treatment plant consists of Sump, Oil-water separator, Slop tank, Filters and Water Collection chambers in the Terminal.

The Objectives of Risk assessment study are as follows:

  • Identification of Hazards (Fire / Explosion uncontrolled release of Hazardous material / Flash Fire / Jet Fire / Over Pressure Explosion etc.)
  • Identification of Maximum Credible Accident (MCA) scenario.
  • Frequency Analysis using internationally accepted database and Evaluation of the -likelihood of occurrence of possible events.
  • Consequence modelling and analysis for the identified hazard covering impact on people and potential escalation.
  • Perform a risk assessment to confirm that risk can be reduced consistent with the ALARP principle according to the UK HSE risk acceptance criteria.
  • Recommendations
HPCL Secunderabad
HPCL Secunderabad