CASE STUDY

Safety Integrity Level (SIL) Determination Study For LSTK-3 Package For Ethylene Glycol Project

NRP projects Private Limited has awarded iFluids Engineering to carry out SIL Determination study for their LSTK- 3 PACKAGE FOR “ETHYLENE GLYCOL PROJECT”.

The MEG from Paradip refinery complex to South Oil Jetty is transferred via a dedicated 20” pipeline. MEG Product stored in the storage tank (207-TK-003A/B/C/D/E) is pumped using MEG ship loading pump (207-P-010A/B/C) and dispatched via tank trucks and ships. Ship loading is likely once or twice a month. After transferring a batch to a ship, MEG product will remain in the pipeline. It is proposed to remove/ recover the MEG in the pipeline immediately after the shipment or at the earliest.

The pigging system is installed for this 20” line. A piggable pipeline facility comprises of a Pig Launcher (207A-A-006A), Metering Skid (CTMS), Loading Arm at SOJ (207A-Z-006) and Receiver (207A-A-006B) at refinery. The Pig will be launched via a pig launcher (207A-A-006A) in the South Oil Jetty (SOJ). Nitrogen will be used as a kicking fluid for pigging the line to remove the MEG product. A pig receiver (207A-A-006B) at the refinery will trap the pig and the recovered MEG will be transferred to the MEG storage tank (207-TK-003A/B/C/D/E) in the refinery. The drain from Pig launcher (207A-A-006A), Metering Skid (CTMS) and Loading Arm (207A-Z-006) is routed to Drain Drum (207A-V-002) via Closed Drain Header. Drain collected in the Drain Drum will be transferred to Road tanker by Drain Drum Pump (207A-P-013A/B). One Drain Drum pump one will be running for normal level and when there is increase in the level the standby pump will be started. The Pig Receiver (207A-A-006B) is routed to existing Glycol Drain Drum (LSTK 2).

The primary objective of this study was to determine the appropriate level of reliability needed to manage the risks associated with each Safety Instrumented Function (SIF) identified in the HAZOP review completed for the project and as per client discussion. The SIL Determination workshop was held on 18th October 2019 at TOYO Engineering, Mumbai. The meeting included the participation of key representatives from LSTK-3 PACKAGE FOR “ETHYLENE GLYCOL PROJECT”. The meeting was conducted by the Chairman from iFluids engineering and also provided the Scribing service as well. This report documents the discussions held and records the proceedings of the SIL Determination workshop. IEC 61508 Risk Graph method has been used for the assignment of SILs as per SIL Guidelines provided by IOCL.

The SIL class will be determined for all safety functionalities utilizing a personnel safety risk graph, environmental risk graph and economic risk graph separately, then suitable ratings for each category have been provided by the SIL Team.

 Safety Integrity Level (SIL) classification evaluates reliability of the Safety Instrumented Functions (SIF) intended to achieve or maintain a safe state for the process, with respect to a hazardous event. The objective of the study is to classify SIL based on associated hazards. The SIL classification study for subject facility is based on guidelines provided in IOCL Safety Integrated Level (SIL) Study Procedure Vide document no: IPEG-6389-8551-RP-002-0038 Rev D3.