Turning wasted cold into profit: New study shows how LNG terminals can recover valuable hydrocarbons using seawater
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A technoeconomic analysis of cryogenic recovery of heavy hydrocarbons from LNG using seawater as the heat source
view moreCredit: Shing-hon Wong, Gongkui Xiao & Dongke Zhang
Every day, liquefied natural gas terminals around the world warm ultra cold LNG back into gas so it can be delivered to homes, power plants, and industry. In the process, an enormous amount of cold energy is released and largely wasted. A new study shows that this overlooked resource could be used to recover valuable hydrocarbons such as ethane and liquefied petroleum gas, creating both economic and environmental benefits.
Researchers from The University of Western Australia have developed and evaluated three process designs that capture higher value hydrocarbons during LNG regasification by using seawater as the heat source. Their analysis shows that all three designs are technically feasible and profitable under typical market conditions, with one configuration delivering especially strong economic performance.
“LNG arrives at terminals at extremely low temperatures, and most of that cold energy is simply discarded,” said lead author Shing Hon Wong. “Our work demonstrates that this cold can be put to work to separate ethane and LPG, which are often far more valuable than natural gas itself.”
Ethane and LPG are important feedstocks for petrochemical production and industrial applications. In many regions, particularly those with strong chemical manufacturing sectors, these products command higher prices than pipeline natural gas. Recovering them directly at LNG receiving terminals could significantly increase the overall value of imported LNG.
The research team used advanced process simulation software to model three alternative configurations for hydrocarbon recovery during LNG regasification. All designs rely on ambient temperature seawater, which is already widely used at LNG terminals, eliminating the need for fuel combustion or high temperature heating utilities.
Two of the designs focused on maximizing the use of LNG cold energy by re condensing methane rich gas streams, allowing pumps to be used instead of energy intensive compressors. The third design operated at lower temperatures to recover the greatest possible amount of ethane, but required additional compression and higher operating costs.
The results showed that ethane recovery ranged from about 91 to 96 percent across the three designs, while LPG recovery exceeded 90 percent in all cases. When economic performance was evaluated, the second design emerged as the most attractive option. For a typical LNG receiving terminal with a capacity of about 3.15 million tonnes per year, this configuration generated an estimated annual net profit of approximately 97 million US dollars.
“What surprised us was how robust the economics were,” Wong said. “Even when we tested different LNG compositions, terminal sizes, and market conditions, the systems remained profitable in most realistic scenarios.”
Beyond economic benefits, the study also highlights environmental advantages. By using seawater as the sole heat source, the proposed systems avoid direct combustion and reduce associated carbon dioxide emissions. The discharge of cooled seawater is comparable to existing LNG vaporization systems and can be managed using standard thermal controls.
The authors emphasize that their analysis is intended as a conceptual and comparative study rather than a site specific design. Actual profitability would depend on local energy prices, LNG composition, and infrastructure. However, the findings clearly indicate that cold energy recovery at LNG terminals is an underused opportunity.
“Our study shows that LNG regasification does not have to be just an energy loss,” Wong said. “With the right process design, it can become a platform for producing higher value products while improving overall efficiency.”
The research appears in the journal Energy and Environment Nexus and contributes to ongoing efforts to make LNG supply chains cleaner, more efficient, and more economically resilient.
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Journal reference: Wong SH, Xiao G, Zhang D. 2025. A technoeconomic analysis of cryogenic recovery of heavy hydrocarbons from LNG using seawater as the heat source. Energy & Environment Nexus 1: e013
https://www.maxapress.com/article/doi/10.48130/een-0025-0013
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About Energy & Environment Nexus:
Energy & Environment Nexus is an open-access journal publishing high-quality research on the interplay between energy systems and environmental sustainability, including renewable energy, carbon mitigation, and green technologies.
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Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
A technoeconomic analysis of cryogenic recovery of heavy hydrocarbons from LNG using seawater as the heat source
Article Publication Date
16-Dec-2025
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