LNG-Coupled Near-Cryogenic Direct Air Carbon Capture Via LNG Regasification and Physisorbents: 300% Cost-Reduction Potential According to Study

     I think this process could put direct carbon capture (DAC) on the map. It could significantly decarbonize LNG and reduce life cycle emissions. If this projected cost reduction is correct, it would make DAC affordable, scalable, and flexible since it could be downscaled for some projects. An LNG construction boom has already started, and this process could lower the carbon intensity of LNG, which some Asian buyers have requested, and projects could be incorporated into carbon offset markets. While DAC tax credits are desirable, especially as demonstration projects begin, they may not be needed after initial commercialization. I believe the 45Q tax credits for carbon capture have been largely left intact at $35-50 per ton of CO2 ($50 if sequestered and $35 if used for EOR or some other purpose), after the “Big Beautiful Bill” was signed into law. This new process may be able to capture carbon as low as $70 per ton of CO2, so with incentives, it could be quite feasible. According to a 2022 article from the World Resources Institute, DAC capture prices range from $250 to $600 per ton of CO2. According to the current paper and article, current DAC capture prices are down to $200 per ton of CO2.

      Researchers at Georgia Tech's School of Chemical and Biomolecular Engineering (ChBE), including members from Oak Ridge National Laboratory in Tennessee and Jeonbuk National University and Chonnam National University in South Korea have developed the new method combining DAC with the regasification of liquefied natural gas (LNG), a common industrial process that produces extremely cold temperatures. During regasification, LNG basically releases or wastes the low temperature energy, often to seawater, a common source of heat for regasification. In this new process, the cold LNG cools the local air, which creates a favorable environment for carbon capture via physisorbents, or porous solids that can adsorb CO2 better than existing methods with amine sorbents. TechXplore explains the advantages of physisorbents:

“Most DAC systems in use today employ amine-based materials that chemically bind CO2 from the air, but they offer relatively limited pore space for capture, degrade over time, and require substantial energy to operate effectively. Physisorbents, however, offer longer lifespans and faster CO₂ uptake but often struggle in warm, humid conditions.”

“The research study showed that when air is cooled to near-cryogenic temperatures for DAC, almost all of the water vapor condenses out of the air. This enables physisorbents to achieve higher CO₂ capture performance without the need for expensive water-removal steps.”

     The result is lower-cost carbon capture that utilizes existing materials and infrastructure. Zeolite 13X and CALF-20 were identified as the leading physisorbents. “Zeolite 13X is an inexpensive and durable desiccant material used in water treatment, while CALF-20 is a metal-organic framework (MOF) known for its stability and CO2 capture performance from flue gas, but not from air.”

     These materials can beat amine-based capture in ambient temperatures by up to three times and also release the captured CO2 with low energy input.

"Beyond their high CO2 capacities, both physisorbents exhibit critical characteristics such as low desorption enthalpy, cost efficiency, scalability, and long-term stability, all of which are essential for real-world applications," said lead author Seo-Yul Kim, a postdoctoral researcher in the Lively Lab.

     The researchers think that the process could potentially capture over 100 million metric tons of CO₂ per year by 2050. While that is only one-tenth of a gigaton, it could still be a significant amount to be captured at a significantly lower cost than conventional DAC. Thus, near-cryogenic DAC can account for approximately 10.6–14.6% of the overall DAC target for 2050 (970 MTPA). The process is limited by the need to have supercooled air, which is only available at these LNG regasification sites and a few other potential cold energy sources. Future research will be focused on refining the process and investigating more physisorbents, including some that have been previously dismissed for ambient temperature DAC.

     Since natural gas liquid (NGL) fractionation also involves cryogenic cooling and cools the local air, I wonder if this DAC process could also be used at NGL fractionation plants. It may be smaller scale, but still effective and economical. Another potential application is in plants that cryogenically remove CO2 from natural gas. There may be other industrial processes where cold energy can be tapped for carbon capture. According to the paper, there are other processes as well that could benefit from the cold energy heat exchange in LNG regasification.

“The regasification process can be integrated by heat exchange with other processes instead, including the Rankine vapor cycle, air separation unit (ASU), adsorbed natural gas, and post-combustion CO2 capture, to provide cold energy to those processes.”

     Most conventional DAC sorbent materials also adsorb significant quantities of water from ambient air, and water removal or desorption is often a major energy penalty. This is not a factor in this new method of near-cryogenic DAC. Water co-adsorption in ambient conditions has been the main limiting factor for physisorbents. This problem is eliminated in a near-cryogenic DAC system. In LNG regasification, the latent heat of vaporization is typically transferred to seawater. Thus, the cold energy is essentially wasted. It can also negatively affect local ecosystems.

“Part of the cold energy provided by LNG regasification or a cooling loop can be used to condense out the water vapor in air during the early stages of heat exchange, resulting in cold air with sub-ppm levels of water vapor. This low water concentration also enables the use of many physisorbents that have previously been ruled out for DAC.”

     Regarding future tweaks to improve the process, they note that better sorbents could be developed. Perhaps AI-machine learning simulations can help find them. They also note:

“…investment in air–air heat exchangers for cold energy recovery is critical to extending the long-term impact of LNG–DAC, which has already been accounted for in the techno-economic analysis”

     The team also notes that further improvements can be achieved by integrating with other cold energy processes:

“Near-cryogenic DAC also offers considerable potential for further energy efficiency improvements through integration with green processes such as Rankine cycles, air separation units (ASU), and hydrogen or ammonia production.”

     Graphics, abstract, and snippets from the paper are given below.

 

    

 

References:

 

Low-cost method can remove CO₂ from air using cold temperatures and common materials. Brad Dixon. TechXplore. July 7, 2025. Low-cost method can remove CO₂ from air using cold temperatures and common materials

Near-cryogenic direct air capture using adsorbents. Seo-Yul Kim, Matthew J. Realff, Akriti Sarswat, Sunghyun Cho, MinGyu Song, Jinsu Kim, David S. Sholld, and Ryan P. Lively. Energy & Environmental Science. June 24, 2025. Near-cryogenic direct air capture using adsorbents - Energy & Environmental Science (RSC Publishing)

One Big Beautiful Bill Act to Scale Back Clean Energy Tax Credits Under Inflation Reduction Act. Holland and Knight. June 30, 2025. One Big Beautiful Bill Act to Scale Back Clean Energy Tax Credits Under Inflation Reduction Act | Insights | Holland & Knight

6 Things to Know About Direct Air Capture. Katie Lebling, Haley Leslie-Bole, Zach Byrum and Liz Bridgwater. World Resources Institute. May 2, 2022. Direct Air Capture: 6 Things To Know | World Resources Institute

Oil & Gas: Natural Gas Processing: NGL Processing. MEI Maverick Engineering. 2016. NGL Extraction & Fractionation

Extracting NGLs Using Cryogenic Processing. Opero Energy. February 23, 2015. Extracting NGLs Using Cryogenic Processing | Blog | Opero Energy

Cryogenic-based CO2 capture technologies: State-of-the-art developments and current challenges. Chunfeng Song, Qingling Liu, Shuai Deng, Hailong Li, and Yutaka Kitamura. Renewable and Sustainable Energy Reviews. Volume 101, March 2019, Pages 265-278. Cryogenic-based CO2 capture technologies: State-of-the-art developments and current challenges - ScienceDirect

Review on cryogenic technologies for CO2 removal from natural gas. Yujing Bi & Yonglin Ju. Frontiers in Energy. Volume 16, pages 793–811, (2022). Review on cryogenic technologies for CO2 removal from natural gas | Frontiers in Energy