Adsorption of Flue Gas on Carbonate and Sandstone Rocks at Typical Reservoir Conditions: Influence of Feed Composition.

Flue gas generated by power plants is considered one of the primary sources of CO2 emissions. Flue gas can be injected into depleted gas reservoirs to minimize the impact of CO2 and other pollutants such as sulfur dioxide (SO2) and nitrogen oxides (NOx). This work investigates the impact of gas impurities in flue gas on CO2 enhanced gas recovery in sandstone and carbonate reservoirs. Sorption analysis was conducted using flue gas with and without gas impurities on carbonate and sandstone rock samples at a temperature range between 50 and 100 °C and pressure up to 45 bar. The results showed that low clay content sandstone has the highest adsorption (17.3 mg/g) of purified flue gas (80%N2/20%CO2) compared to about 13 mg/g for clay-rich sandstone at a temperature of 50 °C and a pressure of 45 bar, which is believed to be a result of pore filling mechanism besides the van der Waals forces between the gas molecules and rock surface. Indiana limestone with low permeability revealed about 11 mg/g at similar conditions. The total gas uptake decreased by an average of 56% in sandstone rocks and 31% in limestone by injecting the flue gas that contained SO2 and NOx, which could be attributed to the higher affinity of these gas impurities to rock surface compared to CO2 and N2. The adsorption/desorption hysteresis in sandstone and carbonate rocks showed that the adsorption is physisorption in all cases. Increasing the temperature decreased the flue gas adsorption without any effect on its nature. [ABSTRACT FROM AUTHOR]