Numerical modeling and investigation on the adsorption kinetics and thermal regulation effects of adsorbent coating for cryogenic storage

Cryogenic storage of liquefied natural gas (LNG) is exposed to environmental heat flux, highlighting the need for thermal regulation of LNG tanks to ensure storage safety and efficiency. Although cold insulation systems are equipped to mitigate heat leakage, auxiliary thermal management measures remain essential. This paper proposes a passive thermal regulation method for LNG tanks, which utilizes adsorbent coatings for thermal control by temperature swing desorption. A numerical model is developed to investigate the adsorption kinetics and thermal regulation effects of adsorbent coating on LNG thermodynamic responses. A coating sub-model is established by incorporating scalar equations of adsorption kinetics and thermal flux into the numerical model. The adsorption isotherms for boil-off gas under cryogenic conditions are established using D-A model based on fitting of cryogenic test data. Simulations indicate that the vapor temperature rise is suppressed by 21.3%, 55.4% and 85.4% when exposed to heat fluxes of 200 W/m 2 , 1,000 W/m 2 , and 10,000 W/m 2 , with a maximum heat adsorption ratio of 50.1%, 78.2%, and 90.1%, respectively. The adsorbent coating exhibits self-adaptive response to external heat flux, effectively suppressing temperature rise and pressure buildup, demonstrating its potential for passive thermal regulation under conventional cryogenic storage and emergency thermal invasion scenarios. • Thermal regulation of LNG storage by adsorbent coating is proposed and investigated. • A numerical model of LNG tank thermodynamic response with BOG desorption is developed. • Adsorption kinetics and thermal flux in adsorbent coating are predicted and analyzed. • Temperature swing desorption inhibits tank thermal stratification and pressurization.