HAZOP study for Auto Heading and De-heading System in DCU Coke Chamber – Numaligarh Refinery

Numaligarh Refinery Limited is a public-sector oil company set up in the year 1993, with its 3 MMT refinery situated in Morangi, Golaghat district, Assam in India. NRL manufactures conventional petroleum products like LPG, Naphtha, Motor Spirit (Light Distillates), Superior Kerosene, Aviation Turbine Fuel, High Speed Diesel (Middle Distillates), Sulphur, Raw Petroleum Coke, Calcined Petroleum Coke (Heavy Ends). NRL has committed to supply 160 TMT per annum of petrochemical grade Naphtha to the Assam Gas Cracker as feed stock, subject to availability of 3.00 MMTPA of crude oil for processing in the refinery.

Numaligarh Refinery Limited has entrusted iFluids Engineering to carry out Hazard and Operability (HAZOP) study for the Auto heading and de-heading system in DCU Coke Chamber-NRL.

Currently, Numaligarh Refinery Limited (NRL) operates a Delayed Coker Unit with two Coke Drums with the unit commissioned, more than 20 years ago. The process of coke cutting and removal is a manual process after each cycle of coking / coke production. The method of manual operations after every cycle is laborious, cumbersome and requires extensive manual work with extensive safety measures for working in an operating process area at substantially elevated temperatures. Hence a Top Unheading Device (TUD) and Bottom Unheading Device (BUD) on each Coke Drum is facilitated for automatic operation of coke cutting and removal. Each TUD and BUD are essentially a motorized valve, specially designed for the services and integrated in overall control system for cyclic automated operation.

The objective of a HAZOP (Hazard & Operability) study is to aid in managing project risk through early identification of hazards and operability problems and to reduce the probability and consequences of an incident that would have a detrimental impact to the personnel, plant, properties and environment

HAZOP study for any project or modification provides many purposes including

  • Identifying the hazards inherent to the proposal.
  • Identifying the credible human and/or equipment instrument failures likely to lead to accident scenarios/ hazards / operability problems.
  • Qualitatively assessing the risk and provide recommendations to overcome the hazards if required.
  • In addition to these issues, HAZOP occasionally identifies items which could improve unit operations and efficiency.