Analysis of the duration of the low-temperature circulation charging of an adsorption methane storage system using the ANSYS Fluent software package

Abstract

Adsorbed natural gas (ANG) systems are a promising alternative to the high-pressure compressed natural gas and low-temperature liquefied natural gas. ANG systems accumulate methane with lower energy consumption and an increased fire and explosion safety due to the gas-bound state in the pores. However, the charging process is complicated due to the thermal effects of adsorption, which reduce the methods energy efficiency, thus needing an additional thermal control. A study of the duration of low-temperature circulation charging of an elementary adsorption cell of various geometries was conducted under different temperature and pressure modes. The charging completion criterion was achieving 95% limit value of the amount of accumulated methane, which was constant for all considered cases. As a result of modeling, a reduction in the duration of gas accumulation was observed with an increase in the operating pressure. It has been established that the charging time is significantly affected by the gas channel opening diameter, required to reduce the hydraulic resistance of the adsorbent layer as when the channel diameter increased from 4 to 6 mm, the charging time decreased by 138 s or 25% on an average. A twofold smaller effect of ~13% was registered with an increase in the diameter from 2 to 4 mm due to the changing cooling nature.