Ichthys LNG Project Uses Smith Flow Control Interlocks for Safe Pipeline Processes

A typical pig trap system mounted with interlocks

Onshore processing facilities at Bladin Point, Darwin (Source: INPEX 2014)
The Ichthys LNG Project, one of the most significant oil and gas projects in the world, is using Smith Flow Control’s safety interlocks and valve actuators throughout its facility to protect its people and equipment during hazardous operations.

Located off the coast of Western Australia, the Ichthys LNG Project is effectively three mega-projects rolled into one, involving some of the largest offshore facilities in the industry, a stateof- the-art onshore processing facility and an 889 km pipeline uniting them for an operational life of at least 40 years.

Over 2000 interlocks and portable actuators from Smith Flow Control (SFC) will be installed throughout the onshore processing facility in Darwin. These safety interlocks provide protection against the over-pressurisation of vessels and other valves across the plant by guaranteeing an open path to pressure relief is maintained at all times during maintenance or other work exercises on process equipment. A simple mechanical valve interlock system ensures that no relief valve can be isolated until the spare relief valve has been brought on-stream. A spare relief capacity enables continuous production while maintenance procedures take place, eliminating the need to isolate and shut down the whole process, maintaining efficiencies at all times.

As an additional layer of safety, interlocks were also specified on the facility’s pig trap, serving the main line from offshore. SFC’s vessel closure interlock was fitted to the 42˝ pig trap, connecting to the large subsea pipeline.

Pig traps allow operators to insert and remove pigs (pipeline tools) without interruption to the pipeline product flow. The greatest danger occurs when opening the pig launcher or receiver door as opening the vessel without first correctly isolating, venting and draining, can cause the trap door to fly open and the pig to shoot out at high speed, with potentially fatal consequences. Key interlocks negate this risk by mechanically proving the ‘closed and isolated’ status that enables venting and draining of pig trap vessels before loading or unloading operations. By fitting an interlock (door lock) to the pig trap door, valves and other equipment on the vessel it ensures that only the correct sequence of events can occur.

Pig trap interlocking is invariably nonlinear, as the stages of isolating, venting and draining are typically complex and repetitive. To support this application, Smith Flow Control supplied Sequence Control Units (SCU’s) to the Ichthys Onshore LNG facilities to ensure correct and safe operation. The SCU is a mechanical key issuing device located close to the valve. It differs from traditional key exchange units in that, upon inserting a permit key, a selector knob is rotated to a fixed position before the next key in the sequence is released. In this way, complex sequences can be accommodated, using the same safety principles, and in an ordered and simple fashion.

The Ichthys LNG Project places great emphasis on the safety and wellbeing of its operators, adhering to best practice Human Factors Engineering (HFE) principles to ensure quality, safety and fit for purpose of equipment and facilities. To help ease any valve operating difficulties, SFC is supplying its EasiDrive portable valve actuators throughout the site.

Portable valve actuators are designed to assist in the operation of valves that would otherwise require a high number of turns using excessive, sustained force by several operators at once. With the tool, one operator can efficiently work banks of valves, while reducing fatigue and injury risk. Portable valve actuators can reduce the stress on workers and improve productivity, especially with valves that may be otherwise difficult to operate because of high torque or where adverse climates make operations more challenging. Interlocked valves were also mounted with portable valve actuator kits, to further simplify operations at the plant.

Conclusion
By taking simple steps to integrate safety into valve operating systems, workers are protected and operations proceed in a designated, safe way. Interlocks are versatile building blocks that can be configured to meet almost any simple or complex procedure. In addition, portable or remote valve drive systems are costeffective ways to operate difficult to open and/or hard to reach valves, protecting personnel while increasing efficiency.

Smith Flow Control
Tel: +44 (0)1376 517901
Email: enquiries@smithflowcontrol.com Web: www.smithflowcontrol.com

Published in Valve User Magazine Issue 34


Autumn 2015 // Issue 34
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