THE PLACEMENT POSITION EFFECT OF ADSORPTIVE NATURAL GAS STORAGE TANKS ON THE HEAT-TRANSFER RATE DURING CHARGING; CFD ANALYSES

Abstract

Achieving thermal equilibrium is crucial for optimizing gas adsorption in adsorbed natural gas (ANG) storage tanks. This study shows that flow turbulence can increase the convective heat-transfer coefficient. The results emphasize the importance of the activated carbon monolith configuration and storage tank positioning in influencing flow turbulence. Activated carbon was synthesized through the chemical activation of walnut-shell precursors using caustic potash at a temperature of 800°C and a residence time of 2 h. Polymeric binders are used to fabricate activated carbon monoliths. The results of the Brunauer-Emmett-Teller analysis indicate that the sample has a surface area of 1413 m²·g^-1, a pore volume of 0.69 cm³·g^-1, and an average pore diameter of 19 Å. Gambit software is used to arrange tanks geometrically in both horizontal and vertical orientations. This includes incorporating porous zones such as perforated and simple monoliths, as well as an annulus zone. Laboratory experiments were conducted to determine the physical properties of the monolith, including viscosity and inertial resistance, which are essential for modeling. The Fluent19 software was utilized to model the delivery of methane gas to ANG tanks at a constant mass flow rate of 0.003 kg·s^-1 and a temperature of 283 K. The simulation was conducted using the delayed-detached eddy simulation approach. The porous zone temperature and annulus zone fluid-flow turbulence were observed. The study reveals that using perforated monoliths in a vertical tank increases flow turbulence rate by 39% and lowers the temperature by up to 10°C.