Processing, storing, and transporting LNG requires a host of valves that must perform reliably under very challenging conditions. These valves must deal with cryogenic temperatures, while meeting strict requirements for tight shutoff and low fugitive emissions.
Our article in the July 2025 issue of LNG Industry on pages 20-24, titled “Valve equipment and accessories improve operations,” shows how specially designed control, isolation, and relief valves have proven themselves in LNG applications.
Figure 1. LNG terminals transfer product between oceangoing ships and pipelines. Most terminals are massive in size and include onshore and offshore facilities, and large storage tanks.
LNG terminal service
Pipelines can effectively transport natural gas over land, but LNG is the preferred product state for transport by ship.
LNG terminals serve as the interface between LNG ships and pipelines.
These facilities employ a multitude of valves that must handle extremely low temperatures and very large piping sizes, while maintaining reliable sealing and minimal emissions.
Liquefaction optimization valves
LNG applications often involve cryogenic temperatures at or below the boiling point of LNG, which is -162°C.
Gas liquefaction is made possible by pressurising the gas, cooling it, then quickly reducing the pressure to sub-cool it further via the Joules-Thomson (J-T) effect.
J-T valves fine-tune the liquefaction process, making immediate, precise adjustments to optimize energy usage. In addition to extreme cold, these valves also experience very high pressure drops, high vibration, and extreme vapor velocities.
Because liquefaction operations are highly energy-intensive, poorly performing J-T valves have enormous negative implications in many areas, including total unit output.
At one site, J-T valve replacement not only generated significant operation savings, but it also increased terminal throughput, allowing an additional LNG ship to be loaded per month.
Low-emission isolation valves
Isolation valves in LNG terminal operations face cryogenic temperatures and variable pressures, and they must reliably provide very tight shutoff and fugitive emissions containment.
The critical importance of isolation valves in LNG operations is exemplified by the world’s largest LNG project to date, where over 2000 Emerson Vanessa triple offset valves (TOVs) were installed.
Figure 2. Emerson supplied a number of triple offset valves for the world’s largest LNG plant.
These valves incorporate advanced emissions-capture technologies and are specifically engineered to meet and exceed the most stringent requirements for operability, tightness, and safety in LNG applications. With numerous sizing and customization options available, thousands of these valves are employed in LNG terminals worldwide.
The success of this TOV solution in the world’s largest LNG facility has led to their selection for the facility’s two-train expansion, further validating their performance in critical applications.
High-capacity relief valves
Most LNG terminals include large storage tanks that depend on relief valves to pipe away vast quantities of gas during overpressure emergencies. Many of these tanks use multiple valves to provide the necessary flow capacity.
Very high-capacity pilot-operated relief valves have been designed to provide tight shutoff to within 5% of setpoint, keeping product loss and environmental emissions to a minimum. Their high flow capacity means that far fewer relief valves are required to fully protect each tank, saving money on device and installation costs, with one facility saving over US$260,000 on installation costs alone.
Figure 3. Extremely high-capacity relief valves, like Emerson’s Anderson Greenwood 9300H low pressure pilot operated relief valves, save significant capital since multiple valves are not required for very large LNG storage tanks.
Proven service
As these real-world examples demonstrate, carefully designed J-T control valves, TOVs, and high-capacity tank relief valves provide efficient and dependable service in LNG terminals, resulting in significant savings.
Looking to upgrade your valves? Visit the Anderson Greenwood and the Joule-Thomson Control Valve Solutions, as well as the Triple Offset Valve Technology sections on Emerson.com to find the right valve that will support your LNG operations.
