Cryogenic carbon capture using efficacious exchange of waste heat energy from flue gas with waste cold energy from LNG

Natural Gas (NG) is chilled to −160 degrees Celsius below its boiling point to generate Liquified Natural Gas (LNG), a liquid suitable for transport or storage. The LNG may then be regasified and delivered via distribution pipelines to different end-users or power generation units. Due to the very low temperature at which it is stored, LNG has a significant amount of exergy, which is released during the regasification process (LNG cold energy). Heat from ocean water and additional gas burners are being used for the regasification of LNG to NG especially in Singapore. This practice of dumping available cold energy causes an aquatic microclimate that has detrimental environmental consequences on marine life and is a negative consequence of LNG facilities. Conversely, excessive CO
2
emissions from flue gas have a substantial impact on the environment and human life. In recent years, there has been a progradation of the necessity to restrict CO
2
emissions in order to protect the environment. Due to its high CO
2
recovery rates and high purity, cryogenic carbon capture (CCC) may emerge as a viable alternative to other CO
2
separation techniques. Producing the cryogenic cold energy required for carbon capture has a downside. The objective of this study is to efficiently use or exchange both waste cold energy from LNG and waste heat energy from flue gas. The cryogenic cold energy from LNG may be utilized to extract CO
2
from flue gas by liquifying it, while the heat energy from flue gas can be used to regasify LNG. In this simulation, CFD simulations of a shell-and-tube heat exchanger was conducted, taking the phase change of flue gas to liquid flue gas and LNG to NG into consideration. To protect environment, it is conceivable to eliminate the utilization of ocean water and extract CO
2
from flue gas. This will contribute significantly to achieving Net Zero Carbon Emissions by 2050. Since it is hard to perform real-time experiments in this project because LNG regasification and flue gas capture need diverse industry collaborations and funds, the proof of concept is shown via the use of virtual CFD modeling.