St Fergus Gas Terminal Furnace Upgrade Project

At a Glance

• Installation of Instrumented systems on the existing furnaces and associated piping to address concerns raised in SIL and HAZOP reviews. Each system was designed to meet commercial and environmental targets. 
• Fuel gas and hot oil pipework and valves to the existing furnaces and associated instrumentation were replaced. 
• A semi-automated start-up sequence was put in place, controlled by a new burner management system (BMS) for each furnace. This reduced the operator interface requirement and ensured compliance with industry standards.
• Installation of new pilot burners on the furnaces. 

Compliance with emission legislation especially pertaining to NOx was ensured
primarily through excess air control using an actuated stack damper. New stacks were also fitted to both furnaces.

Objective & Service

PROJECTS, ENGINEERING & CONSULTANCY

The St. Fergus Gas Terminal (SFGT) processes natural gas extracted from the UK and Norwegian Continental shelves via the FUKA and Vesterled pipelines respectively. The FUKA Pipeline gas is processed through the Phase 3 facilities at the terminal whilst the Vesterled pipeline gas is processed via the Phase 2 facilities. 

The Phase 3 gas processing facilities use hot oil as the heating medium to provide continuous heating for the process and utility heat exchangers. The hot oil is heated using fuel gas in 2-off natural draft API 560 type furnaces each with a design duty of 14MMkcal/hr – issues pertaining to the safety and reliability of the Phase 3 furnaces (F-901 and F-902) were identified following HAZOP and SIL reviews. 

A Furnace Upgrade Project was sanctioned to reduce the risks associated with the start- up, normal operation and shutdown of the furnaces to bring them to ALARP (as low as reasonably practical) status. 

Project Outcome & Results

• Following a number of reviews a detailed design work scope was agreed. 
• Examples of the work scope included but was not limited to: 
  • Installation of instrumented systems on the existing furnaces and associated piping to address concerns raised in
  • SIL and HAZOP reviews: each system was designed to meet commercial and environmental targets. 
  • Fuel gas and hot oil pipework and valves to the existing furnaces and associated instrumentation were replaced. 
  • A semi-automated start-up sequence was put in place, controlled by a new burner management system (BMS) for each furnace. This reduced the operator interface requirement and ensured compliance with industry standards. 
  • Installation of new pilot burners on the furnaces. 
• Compliance with emission legislation especially pertaining to NOx was ensured primarily through excess air control using an actuated stack damper. New stacks were also fitted to both furnaces. 
• This scope was completed in phases with minimum disruption to plant operations, safely and within the Project schedule. This included separate work breakdown structures for the furnace Pre-Outage phase, the outage phase of the furnace F9101, subsequent outage phase of furnace F9102 and Post Outage scope