Enhanced CO₂ Gas Storage in Coal

Abstract

We investigate coal’s performance for storing carbon dioxide (CO2) gas molecules in the form of CO2 hydrates when the in situ hydrates-forming method is applied with the use of promoters. Sodium dodecyl sulfate (SDS) and pressure augmentation were adopted as a promoter for the hydrate formation in coal. The use of SDS considerably increased the rate of hydrates-forming reaction in coal. The calculated rates of the reaction in the presence of SDS reached 143.70 cm3/min at 3 MPa, and 50% of the maximum gas storage capacity was attained within 2 h. Pressure also controlled the final gas storage capacity of coal. The maximum gas storage capacity of coal under 3 MPa was 188.65 volume of CO2 gas at standard temperature (273.15 K) and pressure (100 kPa) condition per unit volume of coal, as compared to 136.30 under 2.3 MPa.