Driving resilience in LNG through innovations in boil-off gas compression

As the global energy landscape evolves, resilience and sustainability have become the defining themes in the transition to a low-carbon future, which also extends to the liquefied natural gas (LNG) value chain.

Managing boil-off gas (BOG), which is produced due to heat ingress during the storage and transportation of LNG, is essential to ensure safety, minimise product loss, and lower emissions in LNG facilities. Particularly in recent years, there has been an increased focus on managing BOG efficiently as LNG operators prioritise both operational safety and environmental responsibility.

Innovation in action

Early LNG facilities, which relied on steam turbine-driven refrigeration compressors, treated BOG primarily as a byproduct to be consumed in boilers for steam generation. Safety was the priority; energy efficiency and emissions reduction were historically underemphasised. As the world’s energy demands grew, so did the need for smarter solutions.
The shift to gas turbine-driven main refrigeration trains in the 1970s and 1980s transformed BOG handling strategies. Gas turbines require a continuous supply of fuel and therefore, utilising BOG was a perfect fit. Siemens Energy introduced centrifugal compressors to recover vapor from LNG tanks and deliver it at the right pressure for combustion, boosting efficiency and reducing flaring.

With the introduction of all-electric motor-driven refrigeration trains (e-LNG), modern e-LNG facilities typically apply high-pressure BOG compressors to capture boil-off gas. This gas is then re-liquefied in the main cryogenic heat exchanger. The result? Lower emissions and maximised gas recovery, helping meet both environmental goals and cost-saving targets.

Designing BOG compressors for modern LNG plants

Designing these compressors is no small feat. They must handle extreme temperatures – from a frigid -160°C up to a scorching +240°C. BOG compression presents unique thermodynamic, mechanical, and materials challenges that are often not seen in other oil and gas applications. Our engineers use specialised materials and smart designs to keep everything running reliably. BOG generation rates aren’t always steady during startup or ship loading – the rates can spike or drop fast. Compressors must be flexible, stable at low flows, and adaptable to changing conditions. Robust control strategies and flexible configurations are key. Siemens Energy has developed several innovations, including specialised cryogenic material technologies and unique compressor arrangements, as well as novel design features to ensure compressor reliability in operation.

Real results, real impact

Siemens Energy has installed over 240 single-shaft centrifugal BOG compressors and more than 100 reciprocating BOG compressors at LNG production facilities and export/import terminals worldwide. Our cryogenic compressors range from 1.5 MW to 33 MW, handle design temperatures below -190°C, and reach discharge pressures over 75 bar. Most are equipped with moveable inlet guide vanes for precise capacity control. Our experience spans onshore and offshore facilities, including floating LNG, powered by everything from natural gas to hydro and nuclear energy.

At ADIPEC, Siemens Energy is sharing lessons from real-world projects, such as the Ruwais e-LNG plant in Abu Dhabi and the Woodfibre e-LNG project in Canada. Our experts will present key insights on Wednesday, November 5, at 10:50 AM in Capital Suite 15, and host a Power Hour at the Siemens Energy stand #3550.

Shaping a resilient and sustainable LNG future

Better BOG compression means LNG plants are safer, cleaner, and more flexible. By capturing and reusing every bit of gas, we help the industry meet tough environmental goals and adapt to changing energy needs. As LNG continues to grow, smart and innovative solutions for BOG management will be key to a sustainable future.