LNG facility upgrades control system

Edited by the Engineeringtalk editorial team Aug 24, 2007

National Grid's Glenmavis LNG facility is now controlled by Yokogawa's latest Centum CS3000 DCS, which forms the basis of the new integrated control and safeguarding system.

Yokogawa UK has been awarded a contract by AMEC to supply an integrated distributed control and safety system for National Grid's LNG storage facility at Glenmavis, Scotland.

The main project consists of the deconstruction of two liquefaction plants originally commissioned in 1973 and the construction of a new Black and Veatch Pritchard design liquefaction plant on the same site.

The liquefaction plants, part of the overall LNG storage facility at Glenmavis, were originally controlled by a Yokogawa Centum CS1000 distributed control system (DCS).

This system has now been upgraded to Yokogawa's latest Centum CS3000 DCS, which forms the basis of the new integrated control and safeguarding system.

The National Grid storage facility provides deliverability to customers depending on their nominations, which are often 'within day', and is capable of re-gasification of LNG at rates exceeding 800GWh per day.

The high reliability and availability of the Yokogawa Centum CS3000 DCS control system enables National Grid to control the process plants within safe operating ranges and to initiate safety trips in the event of abnormal operation.

The CS3000 achieves a reliability of 'seven nines' (99.99999%).

Yokogawa has extended the upgraded Centum CS3000 DCS to control the new liquefaction plant, and has integrated a Yokogawa ProSafe RS safety system for emergency shutdown (ESD) and gas detection logic plus a plant resource management (PRM) system to form an integrated control and safeguarding system.

The upgraded DCS controls the many of the LNG storage process plants and provides an integrated view of all control functions, safety shutdown and gas detection.

It also monitors field device diagnostics for HART-enabled field measurement instrumentation, generating on-line reports directly to operations and maintenance technicians via the DCS operator and maintenance display screens.

"The use of HART-enabled measurement and control instrumentation along with Yokogawa's plant asset management system integrated with the Centum DCS will streamline maintenance operations and reduce operational expenditure", says Martin Ward, Managing Director of Yokogawa UK.

"This system expansion, with its incorporation of smart instruments, demonstrates Yokogawa's commitment to supporting and strengthening existing DCS installations to underpin National Grid's development of a strategy to evolve to predictive maintenance".

A further extension of the plant control system includes the control of new boil-off gas compressors and six new vapourisers.

All these new plant areas have been incorporated into the integrated control and safeguarding system and share the same control room operator workstations.

The original LNG plant control system supplied by Yokogawa was based on a Centum CS1000 DCS, which has proved its worth by not only streamlining existing production but also allowing National Grid to extend the control system to add additional process plants.

"The fact that Yokogawa was chosen to provide the control system for this new process plants reflects the high reliability of the existing Centum DCS on the LNG plant", says Martin Ward.

"The continuing expansion of the Centum CS3000 DCS at National Grid demonstrates the flexibility of the system to incorporate expanded process demands".